ANNUAL consumau oscefssmq-iaim: j. mam-so LABEL‘ED mnasaénsfavif z .133; SMALL MAMMALS m AN 0AK‘~-chmmt FOREST if Thesis for the Degree 62911.9 ‘ Q ' MICHIGAN STATEUNWERSHY ’ . JOHN BEMTY NAMES . 1971 ' ‘ LIB RA R Y Michigan State University This is to certify that the thesis entitled ANNUAL CONSUMPTION 0F '37 CESIUM AND 60 COBALT- LABELED PINE SEEDS BY SMALL MAMMALS IN AN OAK-HICKORY FOREST presented by JOHN BEATTY MATHI ES has been accepted towards fulfillment of the requirements for PH. D. degree in FORESTRY Major professor Date JULY 22, I97] 0—7539 | ABSTRACT ANNUAL CONSUMPTION OF CESIUM-137 AND COBALT-6O LABELED PINE SEEDS BY SMALL MAMMALS IN AN OAK-HICKORY FOREST BY John Beatty Mathies Annual and seasonal consumption of eastern white pine seeds was determined radioisotopically in both laboratory and free-ranging populations of small forest mammals within a 2—ha oak-hickory forest 137 in eastern Tennessee. White-footed mice were chronically—fed Cs and 6OCo-labeled pine seeds in the laboratory, and the resultant uptake, equilibrium, and excretion patterns in mice were used to infer food consumption rates. Seed-ingestion rates, of from 2 to 100 seeds per day, were highly correlated with equilibrium levels of 137 Cs. Lowering the ambient temperature resulted in lower equilibria, through a range of 21.1 C to h.h C; equilibria in males was lower than in female mice. Free-ranging mice rapidly acquired radioactive body burdens of both isotopes. The ratio of the body burdens between these two radioisotopes was used to determine the day of excretion for animals trapped in the field. A laboratory—to-field comparison yielded 137 similar excretion rates of Cs, indicating that metabolic stimuli such as temperature or feeding rate did not overtly influence the rate of excretion. Snap-trapped mice from a second chronically-fed 137 field population indicated a similar tissue distribution of Cs in John Beatty Mathies mice from.both the laboratory and field. Based upon these similarities, a direct correlation was made between the laboratory and field to predict equilibrium levels for mice in the field. 137 Field equilibria of Cs were then correlated to the laboratory data to estimate seed consumption rates. Estimates for consumption of this specific food source, by individual white-footed mice, ranged from a maximum of 2.3 g/day in summer, to a minimum of O.h g/day in winter. The drop in consumption coincided with availability of the mast crop in autumn. Yearly average consumption of seeds was 1.6 g/day per mouse, or 7.0 kcal/day. Caloric input of this specific food was approximately 50% of the daily food requirement for this species. Survival of the short-tailed shrew was excellent in the field plot, compared to previous studies. On one plot, only 16 shrews died out of a total of 2A2 captured, with A shrews captured at least 12 times; thus allowing reliable estimates of pine seed consumption by this "insectivorous" species. Shrews were twice as numerous as mice and acquired body burdens of radioisotopes equivalent to or greater than those observed in mice. Insects, mice, and seeds were considered as potential food sources for this shrew; however, seed consumption proved to be the source of radioactivity. Individual shrews consumed a maximum of this specific food of h.l g/day in autumn, and a minimum of 2.1 g/day in summer. Yearly average consumption of seeds was 3.0 g/day per shrew, or 13.2 kcal/day. Of the total pine seed removed from feeders on the field plot, the white-footed mouse pOpulation consumed 17% and the short-tailed John Beatty Mathies shrew population accounted for 6h%, or approximately four times the consumptive importance of the granivorous mouse. These two species accounted for 81% of all seeds removed from feeders. It appeared that sufficient seeds would escape detection by these two species, and that the disappearance of white pine in mixed forests, such as these, was not completely due to their consumption of seeds. From a radioecological and health physics aspect, the results from chronic feeding of radioisotopes in a food base indicated: 137 1. CS was excreted at a faster rate after injection or single-feeding studies than after chronic feeding. 137Cs after chronic feeding could not be used 2. Excretion of to predict chronic uptake adequately in the same animal. 3. Radiation-dose estimates would be higher if body burdens after chronic feeding were used rather than body burdens after injection. Application of this equilibrium technique would be of value in energy flow studies to characterize the total importance of a consumer within an ecosystem. ANNUAL CONSUMPTION OF CESIUM-l37 AND COBALT-6O LABELED PINE SEEDS BY SMALL MAMMALS IN AN OAK-HICKORY FOREST By John Beatty Mathies A THESIS submitted to Michigan State University in partial fulfillment of the requirements for the degree of DOCTOR OF PHILOSOPHY Department of Forestry 1971 ACKNOWLEDGEMENTS I would like to express appreciation to the following individuals who gave valuable assistance during this study: To J. D. Story, C. E. Baker, L. E. Tucker, J. T. Kitchings, III, and C. Guinn for assistance during the seed-tagging procedures and throughout the study. To D. DiGregorio, Dr. D. J. Nelson, J. Phillips, M. Hogland, N. Griffith, Dr. G. E. Cosgrove, Dr. R. A. Goldstein, P. Sollins, and Dr. R. Farmer, Jr. for assistance with particular problems during the course of the work. To Dr. S. I. Auerbach, Dr. R. 1. Van Hook, Dr. J. P. Witherspoon, Dr. L. W. Gysel, and Dr. R. H. Baker for guidance in reviewing the dissertation. To Dr. G. Schneider, who encouraged me to continue my education, gave valuable guidance during the development of the dissertation, and for the thorough review and suggestions for the final format of the dissertation. And to P. B. Dunaway, who was most instrumental in the development of both the thesis and the student. I especially wish to thank Paul for the long discussions which were valuable in the development of the ideas and processes used during the study. ii I am indebted to Michigan State University for financial aid during the course work, and to Oak Ridge Associated Universities for support during both the research and preparation of the thesis. This research was performed at Oak Ridge National Laboratory and was sponsored by the U. S. Atomic Energy Commission under contract with Union Carbide Corporation. iii II. III. IV. TABLE OF CONTENTS Introduction. . . . . . . . . . . . . . . . . . Literature Review . . . . . . . . . . . . . . . Methods and Materials . . . . . . . . . . . . . A. Development of Radioisotopic Techniques. . B. Preparation of the Food Base . . . . . . . C. Laboratory Procedures. . . . . . . . . . . D. Field Procedures . . . . . . . . . . . . . 1. Area Description. . . . . . . . . . . Climate. . . . . . . . . . . . . Soils. . . . . . . . . . . . . . Vegetation . . . . . . . . . . . Animals. . . . . . . . . . . . . 2. Field Plot Preparation and Techniques E. Radioactivity Determinations . . . . . . . F. Statistical Procedures . . . . . . . . . . Results . . . . . . . . . . . . . . . . . . . . A. Seed Consumption and Radionuclide Turnover by White-footed Mice in the Laboratory . 1. Food Base . . . . . . . . . . . . . . 137Cs and 2. Equilibrium Body Burdens of 3. Internal Radiation Dosages. . . . . . h. Parameters for Chronic Ingestion of 137Cs and 60Co. . . . . . . . . . . . . . iv 11 11 12 15 l9 l9 19 2O 2O 21 23 3O 31 33 33 33 36 39 AO 137 60 5. Parameters for Retention of After Chronic Ingestion . . . . . . . . 6. Effect of Mode of Entry on Retention 137 of CS 0 . . O 0 I . . . C . . O . . O 7. "Mirror Image" of Uptake and 137 CS. 0 O O O O O O O O O 137 60 Cs and Co. . . . . . . Retention of 8. Ratio Between 9. Tissue Distribution of Radioisotopes. . . Environmental and Biotic Factors in all Oak-hiCkOI'y Forest. 0 o o o o o o o o o I 1. Climate and Vegetation. . . . . . . . . . 2. Species Trapped on the Field Plot . . . . 3. Disappearance of Pine Seeds from Feeders. Radioisotopic Body Burdens for Small Mammals in an Oakehickory Forest . . . . . . . . . . 1. Body Burdens in White—footed Mice . . . . 2. Body Burdens in Short-tailed Shrews . . . 3. Body Burdens in Miscellaneous Vertebrates Bases for Determining Seed Consumption in the Field 0 O O O O O I O O O 0 I 0 O O 0 1. Correlation Technique Between the Laboratory and Field Data . . . . . . . 2. Conversion of Field Data to Estimates Seed Consumption Rates in White-footed Mice. Estimated Seed Consumption by Small Forest Mammals . . . . . . . . . . . . lo White-fOOLEd Mice o o o o o o o o o o o 0 2o Short-tailed Shrews o o o o o o o o o o o 3. Seasonal Aspects of Seed Consumption by Small Forest Mammals . . . . . . . . Cs and Co hh A7 51 53 55 57 57 58 6h 69 69 76 8h 87 87 91 93 93 95 97 V. Discussion. . . . . . . . . . . . . . . . . . . . . . . . . 101 A. Estimation of Seed Consumption . . . . . . . . . . . . 101 B. Impact of Small Mammals of Forest Regeneration . . . . 107 C. Effect of Mode of Entry Upon 137Cs Uptake and Retention Parameters . . . . . . . . . . . . . . 110 VI. Summary and Conclusions . . . . . . . . . . . . . . . . . . 11h VII. Literature Cited. . . . . . . . . . . . . . . . . . . . . . 118 VIII. Appendix A: Development of Radioisotopic Techniques for Prediction of Seed Consumption. . . . . . . . . . . . 131 A. Isotope Requirements . . . . . . . . . . . . . . . . . 131 B. Isotopic Uptake by Pine Seeds. . . . . . . . . . . . . 132 C. Estimated Seed Supplies Required for the Study . . . . lhl D. Effect of Acid-leached Seeds on Ingestion. . . . . . . 1A3 E. Isotopic Transfer from Seed to Consumer. . . . . . . . lh6 F. Isotopic Retention of Chronic Versus Single Ingestion . . . . . . . . . . . . . . . . . . 150 IX. Appendix B: Figures and Tables . . . . . . . . . . . . . . 15h X. Appendix C: Multichannel Analyzer System . . . . . . . . . 207 XI. Vita. O O O I O O I O O I O O O O O O 0 0 O I O C I O O O 0 21h vi Table 10 LIST OF TABLES Equilibrium of 137Cs and 60Co in Peromyscus leucopus during chronic ingestion of Pinus strobus seeds for hg days I I I I I I I I I I I I I I I I I I I I I I Retention parameters for 137Cs in Peromyscus leucopus after chronic ingestion of Pinus strobus seeds for h9 dws I I I I I I I I I I I I I I I I I I I I I I Retention parameters for 60Co in Peromyscus leucopgs after chronic ingestion of Pinus strqpus seeds for hg daySI I I I I I I I I I I I I I I I I I I I I I I I Effect of mode of entry upon l370s retention in Peromyscus leucopus and the laboratory mouse (Mus mus culus ) I I I I I I I I I I I I I I I I I I I I I I I Distribution of oven-dry weight, 137Cs, and 60Co in organs or tissues of Peromyscus leuggpus after A9 days of chronic feeding of Pinus strobus seeds in the laboratory . . . . . . . . . . . . . . . . . . . . . . Comparison of climatic data during the study with normal data from the ORNL weather station (X-lO site) . . . . Mean vegetational characteristics by size class on the control, live-trap, and snap-trap field plots. . . . . Seasonal trapping summary of Peromyscus leucopus, Blarina brevicauda, and Tamias striatus on the live- trap and control field plots . . . . . . . . . . . . . Percent distribution of trapping effort and captures of Peromyscus leucopus and Blarina brevicauda at various field locations. . . . . . . . . . . . . . . . . . . . Distribution of oven-dry weight, 137Cs, and 60Co in organs or tissues of Peromyscus leucopus after chronic feeding of Pinus strobus seeds on the snap-trap field plot I I I I I I I I I I I I I I I I I I I I I I I I I vii 37 AS A6 50 56 59 6O 61 62 7h Table 11 12 13 B-l Body burdens of 137Cs and 60Co in arthropods collected from feeders on the live-trap and snap-trap field plots I I I I I I I I I I I I I I I I I I I I I I I I I Body burdens of 137Cs and 60Co in miscellaneous vertebrates captured on the live-trap and snap-trap field plots I I I I I I I I I I I I I I I I I I I I I I Estimates of seasonal and yearly consumption of Pinus strobus seeds by Peromyscus leucgpus and Blarina brevicauda populations on a 2-ha field plot. . . . . . APPENDICES Removal of 13705 from Pinus strobus seeds soaked in pure HCl for 1/3 hr and then in 1.0 N HCl for various timeSI I I I I I I I I I I I I I I I I I I I I I I I I Accumulation of 60Co, Sth, and 22Na in Pinus strobus seeds and subsequent removal by 1.0 N HCl acid . . . . Percent retention of 137Cs, 60Co, Sth, and 22Na by Pinus strobus seeds soaked in 1.0 N HCl for various periOds Of timeI I I I I I I I I I I I I I I I I I I I Concurrent accumulation of 137Cs and 60Co by whole Pinus strobus seeds after various times. . . . . . . . Ingestion and retention of 137Cs and 6000 in four Peromyscus leucopus after one-day feeding of nonleached or acid-treated Pinus strobus seeds. . . . . . . . . . . . 137 60 Whole-body accumulation and excretion of Cs and Co in Peromyscus leucopus during and after lh-day chronic feeding of Pinus strobus seeds . . . . . . . . . . . . Fecal excretion of 137Cs and 60Co by four Peromyscus leucopus after consumption of Pinus strobus seeds for one or fourteen days . . . . . . . . . . . . . . . Concurrent accumulation of 137Cs and 60Co in Pinus strobus seeds and subsequent removal by 0.75 N H2SOA . Mean weight per Pinus strobus seed fed to Peromyscus leucopus in each treatment combination in the laboratory I I I I I I I I I I I I I I I I I I I I I I viii 85 98 135 136 137 TAO 1AA 1h7 152 159 160 Table B-7 B-8 B-lO B-ll B-l2 B-l3 B-lh B-lS Three-way factorial analysis of variance for seed weight fed to Peromyscus leucopus during the laboratory study . . . . . . . . . . . . . . . . . . . Four-way factorial analysis of variance of 13703 dpm/g at equilibrium in Peromyscus leucgpus during A9 days of chronic ingestion of Pinus strobus seeds . . . . . . . Four—way factorial analysis of variance of 60Co dpm/g at equilibrium in Peromyscus leucopus during A9 days of chronic ingestion of Pinus strobus seeds. . . . . . Multiple linear regression of 137Cs dpm/g at equilibrium in Peromyscus leucopus . . . . . . . . . . . . . . . . Uptake and equilibrium parameters for 137Cs in Peromyscus leucopus during chronic ingestion of Pinus strobus seedSI I I I I I I I I I I I I I I I I I I I I I I I I Effect of mode of entry upon 137Cs retention in Peromyscus leucopus. . . . . . . . . . . . . . . . . . Mean l37CS/6OCO ratio in Peromyscus leucopus during and after chronic ingestion of Pinus strobus seeds for A9 days I I I I I I I I I I I I I I I I I I I I I I I I I Weights of organs and tissues of Peromyscus leucopus after M9 days of chronic feeding of Pinus strobus seeds in the laboratory. . . . . . . . . . . . . . . . Chi-square test of radioisotopic distribution in organs or tissues of Peromyscus leucopus after A9 days of chronic feeding of Pinus strobus seeds in the laboratory . . . . . . . . . . . . . . . . . . . . . . Distribution of tree species by size class for three field plots I I I I I I I I I I I I I I I I I I I I I I Seasonal captures per 100 trap nights for Peromyscus leuco us, Blarina brevicauda, and Tamias striatus on the live-trap and control field plots. . . . . . . . . Recaptures of small mammals on the live-trap plot and contrOl Plot I I I I I I I I I I I I I I I I I I I I I Weekly Pinus strobus utilization from feeders by small forest mammals on the live-trap and.snap-trap field PlOtSI I I I I I I I I I I I I I I I I I I I I I ix 161 162 163 16h 165 166 167 169 170 171 172 173 172. Table B-16 B-l7 B-18 B-19 B—2O B—26 B-27 B-28 Comparison of visual estimation of feeder utilization to actual utilization. . . . . . . . . . . . . . . . . 176 Mean body burden of 137Cs and 60Co per trapping period for Peromyscus leucopus and Blarina brevicauda on the live-trap field plot containing Pinus strobus seeds. . . . . . . . . . . . . . . . . . . . . . . . . 177 Seasonal captures of individual small forest mammals on the snap-trap field plot. . . . . . . . . . . . . . 178 Weights of organs and tissues of Peromyscus leucopus from the snap—trap field plot. . . . . . . . . . . . . 179 Radioactivity and Cs/Co ratios of individual Peromyscus leucopus for consecutive captures during the same trapping period on the live-trap field plot. . . . . . 180 Radioactivity and Cs/Co ratios of individual Blarina brevicauda for consecutive captures during the same trapping period on the live-trap field plot. . . . . . 181 Accumulation and retention of 137Cs and 6000 by Blarina brevicauda chronically ingesting 10 Pinus strobus seeds per day at 22 C in the laboratory. . . . . . . . 182 Caging trials to observe antagonistic behavior between Blarina brevicauda and mice in the laboratory. . . . . 183 . 137 60 . Retention of Cs and Co 1n Peromyscus leucopus from the field plots . . . . . . . . . . . . . . . . . 185 137 60 . . Mean Cs/ Co rat1os for Peromyscus leucopus, Blar1na brevicauda, and Tamias striatus at various times after beginning of tagged seed placement on the live-trap field plot I I I I I I I I I I I I I I I I I I I I I I 186 Estimation of consumption rates of Pinus strobus seeds by individual Pergmyscus leucopus on the live-trap field plot I I I I I I I I I I I I I I I I I I I I I I 187 Retention of 137Cs and 6000 in Blarina brevicauda from the field plots . . . . . . . . . . . . . . . . . 189 Estimation of consumption rates of Pinus strobus seeds by individual Blarina brevicauda on the live-trap field plot I I I I I I I I I I I I I I I I I I I I I I 190 B-39 B—ho B-hl B-h2 Weights of Peromyscus leucopus ingesting 2 Pinus strobus seeds per day in the laboratory. . . . . . . . . . . . Weights of Peromyscus leucopus ingesting 10 Pinus strobus seeds per day in the laboratory. . . . . . . . . . . . Weights of Peromyscus leucopus ingesting SO Pinus strobus seeds per day in the laboratory. . . . . . . . . . . . Weights of Peromyscus leucopus ingesting lOO Pinus strobus seeds per day in the laboratory. . . . . . . . . . . . Body burden of 137Cs in Peromyscus leucopus ingesting 2 Pinus strobus seeds per day in the laboratory. . . . Body burden of 137Cs in Peromyscus leucopus ingesting 10 Pinus strobus seeds per day in the laboratory . . . Body burden of 137Cs in Peromyscus leucopus ingesting 50 Pinus strobus seeds per day in the laboratory . . . Body burden of 137Cs in Peromyscus leucopus ingesting 100 Pinus strobus seeds per day in the laboratory. . . Body burden of 60CS in Eeromyscus leucopus ingesting 2 Pinus strobus seeds per day in the laboratory. . . . Body burden of 60Co in Eeromyscus leucopus ingesting 10 Pinus strobus seeds per day in the laboratory . . . Body burden of 6000 in Peromyscus leucopus ingesting SO Pinus strobus seeds per day in the laboratory . . . Body burden of 60Co in Peromyscus leucopus ingesting lOO Pinus strobus seeds per day in the laboratory. . . List of scientific and common names for plants mentioned in the text. . . . . . . . . . . . . . . . . List of scientific and common names for vertebrates listed. in the text I I I I I I I I I I I I I I I I I I xi 193 19h 195 196 197 198 199 200 201 202 203 20h 205 206 Fi 10 11 re LIST OF FIGURES Seed-tagging location in an area for disposal of waste radioactive liquids. . . . . . . . . . . . . . . General layout of the live-trapping field plot, indicating trapping patterns and locations of nest boxes and feeders. . . . . . . . . . . . . . . . . . . Nest box, Sherman live-trap in protective metal can, and aluminum stake used on the live-trap area. . . . . . . Feeder used for disbursing pine seeds on the field are as I I I I I I I I I I I I I I I I I I I I I I I I I Flow diagram for location and distribution of 137Cs and 60Co during Pinus strobus seed-soaking procedures; values are mCi . . . . . . . . . . . . . . . . . . . . Mean accumulation of 137Cs in Peromyscus leuc0pus at sixteen treatment combinations of temperature and chronic ingestion of Pinus strobus seeds . . . . . . . Mean equilibrium of 137Cs in Peromyscus leucopus as a function of ingestion rate and temperature in the laboratory I I I I I I I I I I I I I I I I I I I I Retention of 137Cs after intraperitoneal injection and h9 days of chronic feeding of Pinus strobus seedSI I I I I I I I I I I I I I I I I I I I I I I I I "Mirror image" of 137CS uptake and excretion in Peromyscus leucopus during and after M9 days chronic ingestion of Pinus strobus seeds . . . . . . . . . . . Mean 137Cs/6OCo ratio in Peromyscus leucopus during and after h9 days chronic ingestion of Pinus strobus SeedSI I I I I I I I I I I I I I I I I I I I I I I I I Weekly Pinus strobus seed utilization and ingestion in feeders by small mammals on the live-trap and snap- trap field plots I I I I I I I I I I I I I I I I I I I xii 25 26 27 31+ hl h3 h8 52 5h 65 Fi ure Pa e L l2 Tunneling activities of the short-tailed shrew adjacent to a feeder (bottom left) in the live-trap plot. . . . 68 13 Mean wholeébody burden of 137Cs per trapping period for Peromyscus leucopus and Blarina brevicauda on the live- trap field plot containing Pinus strobus seeds . . . . 70 1h Food storage by Peromyscus leucopus in a nest box. . . 72 15 Mean accumulation and retention of 137Cs under laboratory conditions in short-tailed shrews and white-footed mice chronically ingesting lO Pinus strobus seeds at 22 and 2101 C, respeCtiVely o o o o o o o o o o o o o o o o o 78 16 Example of nonantagonistic behavior between short-tailed shrews and white-footed mice . . . . . . . . . . . . . 81 17 Mean retention of 137Cs in Peromyscus leucopus from the laboratory and field . . . . . . . . . . . . . . . . . 89 18 Mean retention of 1370s in Blarina brevicauda from the laboratory and field I I I I I I I I I I I I I I I I I 96 APPENDICES A-l Removal of 13705 from Pinus strobus seeds soaked in pure HCl for 1/3 hr and then in 1.0 N HCl for variable timeSI I I I I I I I I I I I I I I I I I I I I I I I I 13h A-2 Percent retention of 137Cs, 6000, Sth, and 22Na by Pinus strobus seeds soaked in 1.0 N HCl. . . . . . . . 138 A-3 Percent retention of 13703 and 6000 in Peromyscus leucopus after one—day feeding of Pinus strobus seeds. lbs A-h Accumulation of l37Cs and 60Co in Peromyscus leuCOEES through fourteen-day chronic feeding of Pinus strobus seedSI I I I I I I I I I I I I I I I I I I I I I I I I 1248 A-S Retention of 137Cs and 60Co by Peromygcus leucopus after chronic ingestion of tagged Pinus strobus seeds for fourteen days I I I I I I I I I I I I I I I I I I I I I 1’49 A-6 Fecal excretion of 137Cs and 60Co by Peromyscus leucopus after consumption of Pinus strobus seeds for one or fourteen days I I I I I I I I I I I I I I I I I I I I I 15].. xiii C-1 C-2 C-3 Modified latin square design for individual Peromyscus leucopus in each treatment combination . . . . . . . . Whole—body equilibrium in Peromyscus leucopus as in- fluenced by temperature and ingestion rate . . . . . . Whole-body burden of 137Cs for individual Peromyscg§_ leucopus from the live-trap field plot throughout 58 weeks of feeding Pinus strobus seeds . . . . . . . . . Whole-body burden of 137CS for individual Blarina brevicauda from the live-trap field plot throughout 58 weeks of feeding Pinus strobus seeds . . . . . . . . . . 137 . . Comparison of Cs retention by three speCies of mammals I I I I I I I I I I I I I I I I I I I I I I I I Equipment utilized for radioactivity measurements. . . Container used to control geometry of small mammals during radioactivity determinations. . . . . . . . . . Influence of channel drift of the 137Cs peak upon computed radioactivity in the same sample using the RESAP analysis I I I I I I I I I I I I I I I I I I I I Correlation of the computed 137Cs radioactivity to the computed coefficient of variation using the RESAP aI-lalySis I I I I I I I I I I I I I I I I I I I I I I I xiv 15h 155 156 157 158 208 209 211 212 I. INTRODUCTION Estimating rates of food consumption is a major problem in studies of energy or nutrient flow through free-ranging animals in natural environments. Food—consumption rates derived from laboratory studies often form the basis for extrapolation to field situations. While such extrapolations have proven effective with microorganisms and invertebrates, those involving vertebrates are confounded by behavioral and metabolic changes. Consequent effects of such changes on food ingestion are difficult to identify or measure accurately. Both direct and indirect field techniques have been used in range and wildlife research to avoid errors of laboratory—to-field extrapo- lations (USDA, 1970). Examples of direct observations are the feeding- minute, bite—count, and grazed—plant methods employed with ruminants. Chemical methods, such as dyes and chromic oxide, are commonly used indirect techniques. These techniques are primarily concerned with feeding and assimilation estimates for ruminants with high rates of ingestion. While stable chemicals have had widespread application in food consumption and assimilation trials, the use of radionuclides has been limited in forest and range research. Radioisotopes have been used successfully to determine food consumption rates in insects and to follow movements of nocturnal and fossorial species which are difficult 137 to Observe directly. Evidence from human body burdens of Cs suggests a dependence between the acquired body burden and the fallout levels of radionuclides in human foods (ICRP, 1960). This led to a thesis hypothesis that the equilibrium body burden acquired from chronic in- gestion of a "tagged" food base would allow an accurate estimation of food-ingestion rates in secretive species such as small mammals under natural field conditions. Granivorous mammals have long been recognized as a biotic factor limiting the success of both natural and artificial regeneration practices on forest lands. Whereas laboratory studies have estimated consumption rates of rodents, field quantification has rarely been attempted due to the lack of a reliable technique. This study attempted to identify consumers of eastern white pine (Pinus strobus) seeds and to quantify their importance as granivores in an oak-hickory forest ecosystem. Seed consumers potentially have an important role in affecting stand composition and distribution by their seed consumption preferences. The economic value of white pine and the successional disappearance of pine in climax oak-hickory forests prompted the use of white pine in this study. The objectives of this study were twofold: l. to develop a radioisotopic technique for predicting consumption rates of white pine seeds by the white- footed mouse (Peromyscus leucopus) in the laboratory, and, 2. to apply the radioisotopic technique in determining consumption rates of white pine seed by small forest mammals in an oak-hickory forest of eastern Tennessee. II. LITERATURE REVIEW Ecological applications of radioisotopes have been reported in studies of: l) dispersal of organisms, 2) determination of food chains and trophic levels, 3) biological concentration factors of elements within organisms, h) ingestion—excretion rates and equilibrium levels of chemical substances, and 5) tagging of food substances and identi- fication of consumers. Early applications of radioisotopes were primarily dispersal studies of insects (Jenkins and Hassett, 1950; Arnason gt_§1,, 1950). Mammalian studies were also conducted with wild rodents which were either externally tagged with radioactive pellets and their movements traced with Geiger—Muller counters (Griffin, 1952; Godfrey, 195M), or internally tagged and their excreta located on "dropping boards" (Miller, 1957). Studies of animal dispersal using radioactive tags have continued (Kaye, 1961; Tester, 1963; Jenkins, 1963; Lamb gt_al,, 1971). Radionuclides have been successfully applied in determining food chains and trophic levels, primarily in insects. Individual plants were injected with an isotope, and sequential examinations were then made to determine which insects acquired radioactivity (Pendleton and Grundmann, l95h; Wiegert and Lindeborg, 196D; Paris and Sikora, 1965). Radioactive insects were thus part of a food chain based upon the injected plant species. Time delays between plant injection and maximum radioactivity in various insect species were used to in- dicate trophic relationships (Marples, 1966; Wiegert §t_§l,, 1967; Shure, 1970). Animals accumulate body pools of elements, including radioisotopes, and the ratio of the element in the animal to the element in the animals' food is termed the concentration factor. This factor varies consid- erably depending upon the trophic level, organism, and specific activity of the radioisotope (Kaye and Nelson, 1968; Reichle §t_al,, 1970). Concentration factors decrease in terrestrial vertebrate food chains for many radionuclides, but more emphasis has been placed upon those radioisotopes which concentrate as they move through the trophic levels (Odum, 1959). The concentration factor appears to be a consistent parameter for a specific step in a food chain (Reed and Nelson, 1969). Numerous studies indicate that under chronic ingestion regimes, 13703, as in a fallout-contaminated zone, certain isotopes, such as will build up in the body pool to an equilibrium level corresponding to the daily ingestion rate multiplied by this concentration factor (Richmond 93 -a_._]___., 1962; Furchner 333;” 1965; Pendleton 3331., 1965). 137 The concentration factor for Cs between two trophic levels has been reported to range from 0.3 to 15.9, with an average of 3 ap- pearing commonly (Pendleton gt E13, 1965; Jenkins §t_§l,, 1969). The basic formula for predicting equilibrium body burdens of radioisotopes has been used successfully in seVeral studies (Davis and Foster, 1958; ICRP, 1960; Kaye and Dunaway, 1962): Q8 = ra/A. where Qe = equilibrium body burden, r = ingestion rate, a = assimila- tion, and A = the elimination rate coefficient. Generally, the elimination rate coefficient (A) is estimated from the whole4body retention curve after a single feeding of radio- active food. Retention curves for nonbone-seeking radioisotopes are characterized as exponentials with one or more components in the form: where Rt = retention at time t, ai = quantity of total isotope par- ticipating in the ith component, 11 = elimination rate coefficient of the ith component, t = time after feeding or injection, and n = number of components (Richmond, 1958). Further refinements of this retention technique have allowed estimates of food consumption in insects (Crossley, 1963; Reichle and Crossley, 1965; Reichle, 1967, 1968, and 1969; Van Hook and Crossley, 1969; Crossley and Reichle, 1969; Crossley and Van Hook, 1970; Van Hook §t_§l,, 1970), and fish (Kolehmainen and Nelson, 1969). There are at least three assumptions made in using this method. One assumption is that a radioisotope behaves identically during uptake as it does during excretion. Another assumption is that a radioisotope mixes thoroughly with stable isotopes of the element and is not discriminated for or against by these same stable isotopes (Robertson, 1957). A third is that radionuclide assimilation and incorporation after single feeding or injection simulates assimilation and incorporation after chronic feeding. Many investigators have examined excretion patterns in mammals after injection of various isotopes (Reichle §t_§l,, 1970; Stara §£_§13, 1971). The major emphasis of such studies was to determine radiation dosages delivered to mammals by long—term retention of 137 radioisotOpes. Reduced retention of injected Cs has been sig— nificantly correlated with lowered temperature (Furchner and Richmond, 1963; Mahlum and Sikov, 1968), lowered body weight (Eberhardt, 1967; Reichle 533211., 1970; Stara 3351., 1971), younger ages (Matsusaka gt_al,, 1967; Lengemann, 1970), higher potassium levels in the diet (Mraz and Patrick, 1957; Mraz, 1959), smaller species (Richmond, 1958), and increased X—irradiation (Kereiakes £31., 1961). Several experiments have utilized an oral method for delivery of the isotOpe into the mammal. The purpose of these studies was to determine whether excretion data derived from investigations with injected animals could be extrapolated accurately to chronic- feeding studies. The animals were provided with contaminated drinking water rather than actual food. The inherent assumption was that drinking simulated the same process as food consumption, with absorption and assimilation occurring in a similar manner and location throughout the gastrointestinal tract. These investigations indicated general agreement between the two methods (Cook 22 21,, 1956; Ballou and Thompson, 1958; Bernard gt_§1,, 1963). Equilibrium level was influenced by age and temperature in laboratory animals (Richmond 3331., 1962; Furchner 33%., 1965). A few studies attempted administration of the isotope directly in a food base (Nold gt_al,, 1962; French gt_al,, 1965; Comar gt_§l,, 1967). The general procedure has been to reduce dry food pellets to a gruel by addition of the isotope in liquid form, reforming the pellets in various ways, and drying (Finkel gt_al,, 1960; Van Hook and Crossley, 1969; Crossley and Van Hook, 1970). Others have soaked vegetable foods with or in an isotopic solution and fed the food after drying (Hubbell gt_§l,, 1965; Kitchings gt_al,, 1969). Seeds have been used as a food base after spraying or painting the isotope on the seed coat (Tagami, 1962; French gt_§l,, 1965; Orr, 1967; Quink g3_21,, 1970). Kitchings 23_21, (1969) found that the mode of ingestion and food type influenced retention of l3th, with chronic ingestion resulting in longer biological half—lives than single feeding. They also observed differences in excretion of l3th between laboratory-born and wild-caught cotton rats (Sigmodon hispidus), presumably due to differences in musculature. French (1967) concluded that the food base influenced the quantity of ingested radioactivity under fallout conditions, with herbivores consuming more radioactivity than granivores. Summaries of excretion in various species, combining all modes of entry, suggested that 137 ruminants excrete Cs faster than other mammals (Reichle §t_al,, 1970; Stara gt_§l,, 1971). A recent study of 60Co in rats indicated a fourfold increased absorption when rats were given 6OCoCl2 by gastric intubation instead of by their drinking water (Smith gt_§1,, 1971). Several investigators suggested a dependence between ingestion rates of radioactivity and equilibrium body burden (Langham and Anderson, 1959; Scott, 196A; Pendleton gt_§l3, 1965; Whicker §t_§l,, 1967). Such a dependence would be of interest in food consumption studies, since the readily-measured equilibrium could be used to predict the ingestion rates of foods. One such application would be a determination of which mammals were consuming seeds used in forest regeneration efforts. While success of regeneration efforts is dependent upon favorable abiotic or environmental conditions, it is also often dependent upon the absence of various biotic stresses. Willis (191A) concluded that rodents "...must be controlled or seeding must be given up." Later studies have also emphasized the same problems (Wahlenberg, 1925; Smith and Aldous, 19h7; Schroeder, 1950; Shaw, 195a; Hagar, 1960; Seidel and Rogers, 1965; Schubert gt_§1,, 1970). Tree seedlings have been a primary means of refor- estation, but high costs have prompted repeated attempts at direct seeding and research into development of mechanical and chemical procedures to enhance these attempts (Keyes and Smith, 19h3; Kverno, l95h; Spencer, l95h; Russell, 1968; Mann, 1970). A few investigators have examined the causative agents of seed loss, but a reliable technique has not been available for determining the ultimate fate of all seeds. Although consumers were identified by examination of seed-coat fragments (Turcek, 1956; Derr and Mann, 1959; Stevenson gt 2&3, 1963), other studies indicated a large percentage of seed missing, for which no causative agent was apparent (Stein, 1957; Abbott, 1961; Boyer, 196A; Graber, 1969)- The difficulty in relocating seeds after dispersal in the environment prompted the use of radioisotopes to assist in determining the fate of individual seeds. Lawrence and Rediske (1960, 1962) were the first to use an isotope to determine the fate of sown seeds. They soaked th Douglas-fir seeds for 1 hr in h6Sc, tagging the seed coat, and placed them in a grid of seed spots within a recently clearcut forest area. After 22 weeks exposure they recovered 96% of the seeds or their remains and estimated an 8% loss to rodents, based upon characteristics of the seed-coat fragments. Total loss to all agents was about h5%. As their study was undertaken con- currently with the aerial seeding of the 16-ha clearcut, using endrin- treated seeds, the low percentages attributed to rodents was probably due to the repellent qualities of such treated seeds on the clear- cut area. Radvanyi (1966) examined the fate of sown white spruce seeds, using seeds soaked for h hr in 146Sc, and recovered 91% of the seeds after 98 to 118 days in the field. Breakdown of seed consumption by granivores was accomplished by comparison of the seed-coat remains with those obtained in laboratory—feeding trials. After examination of the recovered seeds or their fragments, mice and voles were estimated to have destroyed 35% of the seeds, while chipmunks and shrews accounted for another 12%. Total loss to mammals was h7%. Radvanyi (1970) later reported an average of 3h% destroyed by all agents, based upon 7,800 radio-tagged white spruce seeds (6,838 recovered) in seven separate studies. He attributed 2A% of the losses to mice, and h% to shrews. Abbott and Quink (1970) used eastern white pine seeds tagged with L‘6Sc to locate caches of seeds removed from feeders. After 10 mixing uncontaminated seeds with tagged seeds, in a ratio of 38:1, they recovered a maximum of 10% of the tagged seeds. Abbott (1961) determined ad libitum ingestion rates for rodents in the laboratory. White-footed mice and red-back voles consumed 109 and 97 eastern white pine seeds per day, respectively. He then conducted a field test and determined total seed consumption from feeder losses. Trapping on his 0.2-ha field plot produced 22 mice and voles, and by attributing all seed losses to them, Abbott estimated a consumption rate of 260 seeds per day for the white-footed mouse and 232 seeds per day for the red-back vole. Abbott and Quink (1970) used similar methods to determine a con- sumption rate of 37% white pine seeds per day for the white-footed mouse. Apparently no attempt was made in any of these studies to see if the mammals living on the tagged areas contained any radioactivity. Virtually no information exists on chronic food consumption and ingestion-excretion rates of radioisotopes by small forest mammals under both laboratory and field conditions. III. METHODS AND MATERIALS A. Development 9£_Radioisotopic Techniques There was little information in the literature concerning prepa— ration of a radionuclide-tagged natural food base, and the major portion of a developmental study (Appendix A) was directed towards Obtaining a uniform co-distribution of two radioisotopes in seeds. A natural food of the white-footed mouse was desired, with radio- isotOpes incorporated evenly throughout the food. For this purpose, a small seed was desired to enhance the uniformity of isotOpic con- centration throughout the seeds. White pine seeds were selected because of their uniform size, and commercial availability in large quantities. This species is fairly tolerant, economically important, and is found in mixed forests in eastern Tennessee. General procedures were to soak pine seeds for variable periods of time in a solution of distilled water and the chloride form of 137 60 5h 22 one of four radioisotopes: Cs, Co, Mn, or Na. Radio- activity was assayed to determine total uptake as a function of time, and location in the seeds. An acid—leach procedure was employed to remove excess radioisotopes from the seed coats. 137 60 After these single-isotope tests were completed, Cs and Co 137 were selected for use during the study. The first, Cs, would act as a tissue integrator of the animals' periodic food ingestion, whereas the second, 6OCo, would be used as a food tag with very low 11 l2 tissue assimilation. Two tests were made using both isotopes in a dual-soaking procedure, to establish the final techniques (Appendix A). Transfer of radioactivity from seeds to consumer was examined to establish desired radioisotopic levels in seeds. These tests involved feeding pine seeds to white-footed mice to determine what portion of the seed and resultant radioactivity was ingested, and the accumulation factors that could be expected for these radio— 137 isotopes in mice. Equilibrium levels for Cs were h.3 times the first days radioactivity, and 1.7 times for 6000. B. Preparation 2£_the Food Base The white pine seed originated from the Adirondack Mountains of New York, 1967 seed crop, and germination was certified as 73% (Seed Lot A163, Herbst Bros., Brewster, New York). A total of 59 kg of seed was used during both the laboratory and field portions of the study (Appendix A). 137Cs and 55h mCi of 60Co were used for A total of 71 mCi of tagging the 59 kg of pine seed. These radioisotopes were ordered from the Isotopes Division, Oak Ridge National Laboratory (ORNL). Radiation levels were too high to complete this work inside the Ecological Sciences Division facilities, and a field area within a radioactivity liquid waste disposal area (adjacent to Chemical Waste Pit No. 2) was used. A 380-liter stainless steel kettle with a bottom drain was used for the soaking procedure. A drainage line fed into a vertical, 9-m cruShed limestone pit for disposal of waste isotope solutions. The general layout of the area is shown in Fig. 1. 13 .aonmpsoo mcflgmfinw omlpampoo on» Sony coflpwflvwh mcfixomno u u can mmwmow mcfldem pow onMflooe oappox n p mcoflpdaom oQOpOmfl mums: o>oaoh op sflmao u .muwddfia o>fipomow©mh mumm3 mo admomwfiw mow swam 2d CH cowpmooa mcfimwwplcmom mnv’L: ....x.v.z.a Ls» .. ( . A 933a 1h Soaking procedures were supervised by the Health Physics Division (ORNL) and were begun after 183 liters of distilled water and both isotopes had been well mixed in the kettle. The pH of this solution was h.5. A plastic lid, cut to the size of the kettle, was placed over the seeds and forced down until all seeds were submerged in the solution throughout the h8-hr soaking period. A plastic tarp and metal lid were placed on top of the kettle to prevent evaporation. Seed samples were removed periodically to quantify isotopic location and movement throughout the tagging procedures. Temperature of the soaking solution varied from 2h.0 to 29.5 C. Dry ice was placed on top of the kettle to cool the contents during the first day when air temperatures exceeded 32 C. All seeds were dried for 1 1/2 hr, and then stored in refrigerators at 5 C for one week. At the end of this period, the seeds were soaked for 2 hr in 0.75 N H2SOh. Seed samples were removed at l/2—hr intervals for analysis of isotopic loss during this procedure. The seeds were then washed three times using 75 liters of distilled water for each rinse and allowed to drain overnight. 0n the following day, the seeds were spread on blotter paper for 6 hr of air-drying. A11 seeds were then stored in garbage cans lined with blotter paper for four days while moisture content was determined. As the moisture content was still high, all seeds were dried again on the fourth day to reduce moisture content to the desired level of 5%. Aliquots of each isotope were assayed by Analytical Chemistry 137Cs indicated a total of 60 71 mCi had been delivered on an order of 70 mCi. However, the Co Division personnel (ORNL). The assay for assay revealed a serious error in the quantity delivered. A total 15 of 200 mCi was ordered, but the assay indicated that 55h mCi had been delivered. The result of this error was an increase in radiation dosage during the soaking procedures, with two personnel exceeding the weekly maximum specified by the health physicist present. The seeds contained more 6000 than desired, increasing my exposure through- out the study. My dose rate averaged approximately 250 mrad/3 months, or about 50% of the quarterly maximum specified by the Health Physics Division, throughout the data collection period. C. Laboratory Procedures This portion of the study was designed to determine uptake and 137 equilibrium characteristics of Cs and 60Co in white-footed mice fed tagged pine seeds chronically. Variables examined were feeding rate, sex, and temperature. 137 The influence of feeding rate on Cs equilibrium was the primary unknown variable in the study. Earlier studies assumed a high cor- relation between ingestion rate of radioisotopes and body burden, but no positive correlation was explicitly determined under controlled laboratory conditions. Four feeding levels were established to span the expected range of seed consumption during the field portion of the study. These were 2, 10, 50, and 100 seeds per day. Seeds were taken out of refrigeration and kept at room temperature for three days before use. All seeds fed to laboratory animals were individually counted into appropriate seed lots, weighed, and stored in numbered plastic boxes corresponding to the animals' number, feeding rate, and day fed. Radioactivity measurements were made on 100 undamaged 16 whole endosperm, which were shelled by experimental animals, in order to estimate actual ingested radioactivity. Sex has not been shown to be a significant factor in injection studies, but was shown to be significant in humans ingesting fallout 137Cs (Scott, 196A). Consequently, each treatment combination levels of was composed of equal numbers of males and females, to ascertain if sex was a variable in chronic feeding studies. Four temperatures were selected corresponding to the seasonal mean temperatures for this vicinity. Environmental chambers were used to control temperatures at h.h, 10.0, 15.6, and 21.1 :_1 C for winter, autumn, spring, and summer, respectively. Mice were acclimated for one month at the appropriate temperature before initiation of the experiment. White—footed mice used in the study were live-trapped from various locations on the Reservation. Each seasonal study used 2h mice, with 3 males and 3 females randomly assigned to each of the four feeding rates. Mice were housed individually in clear plastic disposable cages (Maryland Plastics, # 21 Econo—cage and # 22 Econo-lid) with an elevated hardware cloth floor above a layer of blotter paper. Each animal was provided with one—half of a soft drink can, secured to the 0.3-cm mesh hardware cloth, which served as a retreat for the mice. Nesting material was three cotton balls (1 to 1 1/2 g) and 'was changed weekly. Cages and hardware cloths were cleaned of urine and feces each counting period, and new blotter paper was provided each week during the uptake phase. Laboratory chow (Purina Laboratory l7 Chow) and water were provided.ad libitum ; tagged pine seeds were fed at 1800 hr each day. Experimental animals were placed in the environmental chamber in a modified Latin Square design (Fig. B-l), which remained the same at all temperatures. In order to control the influence of variables other than temperature as much as possible, all seasonal studies were conducted in the same environmental chamber for the duration of the uptake phase. When the next seasonal study was initiated, the prior season's excretion phase was not complete, and the animals were trans- ferred into a second chamber for the duration of the excretion study. Both chambers were operated on a l2—hr light (0600-1800 hr), 12-hr dark (1800-0600 hr) regime. No humidity control was present for these chambers, and recorded humidities were slightly moderated from ambient relative humidity. Mice were counted for radioactivity 12 times during h9 days chronic feeding of pine seed. The 2h mice in each seasonal study could not be counted on the same day due to time limitations, and 12 mice were counted on each of 2 consecutive days. With few exceptions, counting periods were from 0800 hr to 1130 hr each morning. At the end of the h9-day uptake period, two mice in each treat- ment combination (one male and one female) were sacrificed for tissue analyses. Major body organs were weighed immediately upon removal from the carcass, dried at 50 C for a minimum of AB hr, reweighed, and then counted for radioactivity. Tissue analyses were used to char— acterize isotopic distribution in mice at equilibrium.body burdens of radioisotopes. 18 The remaining four mice in each treatment combination were counted for radioactivity fifteen times during a 100—day excretion period. The animals were transferred into new uncontaminated cages on day A9 of excretion. These new cages contained an absorbent animal bedding, a tin can (8 x 8 x 11 cm) for housing, and three cotton balls for nest material. Sunflower seeds were provided throughout the excretion phase in amounts approximately equivalent to the number of pine seeds each mouse had been fed previously. Short-tailed shrews were not considered for laboratory study until field results indicated that they contained substantial amounts of radioactivity. A single treatment combination was established to ascertain whether short—tailed shrews would consume pine seeds if given a choice of various foods. Four shrews were maintained at 22 C, but in a communal animal room rather than an environmental chamber. These shrews were fed 10 tagged pine seeds per day for a period of M9 days. All shrews were housed in similar plastic cages as were the mice, but with wire mesh tops (Maryland Plastics, # 28 Econo—lid). These cages contained absorbent animal bedding and a piece of grass sod as a retreat, and were changed weekly. Shrews were fed laboratory chow, sunflower seeds, and water ad libitum, and 2-h g of mouse meat daily. Shrews were counted for radioactivity on the same schedule as ndce, but none were sacrificed at the end of the uptake phase. Ex- cretion was examined for h9 days. 19 D. Field Procedures 1. Area Description Climate. The Oak Ridge area lies within the warm temperate rainy climate (Koppen's classification in Petterssen, 1958). As such, the climate is characterized as having moderate winters, hot summers, and no dry season. Normal temperatures at Oak Ridge National Laboratory (X-lO site) range from 31.1 C in July to -O.h C in January with a yearly average temperature of lh.7 C. Extremes range from -22.2 C recorded in January, 1963 to 39.h C recorded in September, l95h. Seasonal mean temperatures were 6.0 C in winter, 19.1 C in spring, 23.5 C in summer, and 9.3 C in autumn. The average growing season is about 200 days. Normal precipitation ranges from a low of 7.16 cm for October to a bimodal maximum of 13.82 cm for March and 13.h9 cm in July. Total precipitation averages 130.86 cm yearly. Mean seasonal pre- cipitation totals h0.82 cm in winter, 27.9h cm in spring, 32.82 cm in summer, and 29.29 cm in autumn. Prevailing winds parallel the valleys in this region, averaging 7.9 km per hr. Spring and summer winds are generally southwesterly, whereas autumn and winter winds are predominately northeasterly. Weather measurements were made on all three plots including weekly maximum-minimum temperatures, and weekly precipitation. Additionally, hygrothermograph measurements were recorded on the live-trapping plot. Rain gauges were placed in pairs in clearings adjacent to each field plot. These gauges were constructed from 3—liter Nalgene bottles with 20 the top removed and a 12.7-cm plastic funnel glued into the top. A hole was melted into the side of each bottle for removal of accumulated precipitation, and was stoppered at all other times. EEEEE: Soils of this region are primarily Utisols (Red-yellow podzolic soils) derived from Knox Dolomite. Ridges generally form similar soils due to geologic folding of the parent material, and the field plots were located along one ridge to reduce variation due to extreme changes in soil type and consequent chemical composition (especially potassium concentrations) of the vegetation. Peters §t_§13 (1970) described the soils of Walker Branch watershed, which is located on the same ridge (Chestnut Ridge) approximately 1.6 km northeast of the nearest field plot used in this study. This 97-ha watershed was intensively surveyed by U. S. Soil Conservation Service personnel in 1967. Seven soil series were classified on this area with 90 to 96% of the total watershed classified as either Fullerton or Bodine soil series. These soils were found along the ridge with Fullerton commonly above Bodine in slope position. As the field plots were located so as to saddle Chestnut Ridge, it is likely that these two soil series predominate on the plots. Vegetation. The field work was conducted in mature hardwood forests of the Eastern Deciduous Forest. These forests originally were of the Oak-Chestnut association (oak-deer—chestnut fasciation), changing to an oak-hickory forest since the disappearance of American chestnut (Shelford, 1963). More commonly, this forest is within the Ridge and Valley Province of the Oak-Chestnut Forest region (Braun, 1950). It was typified as oak-chestnut forests on the ridges, with 21 predominately oak forests in the valleys. Braun (1950) considered "...each ridge is more or less a unit..." which served to increase the uniformity of the forests growing thereupon. The Knoxville area was considered part of the valley floor vegetation, with low relief formed by dissection of the valley floor. Vegetation was classified as very uniform, with white oak predominating in the climax community despite the low ridges. These cherty ridges were considered to be predominately white oakéblack oak-hickory with a scattering of other species. Three field plots were selected during the winter of 1968-69, based upon similarities in the following criteria: basal area (prism estimates), dbh (diameter at breast height, or 1.h m above the ground), total height, species composition, aspect, position on the ridge, number of stumps and logs on the ground, and visible ground cover. Vegetation was subsampled on 10 randomly selected, 10-m square subplots in each field plot. All trees over 2.5 cm dbh were tallied by species and dbh. Trees over 12.7 cm dbh were also measured for total height with a Haga altimeter. Ground cover was visually estimated on each subplot for each of three height classes of vegetation. These classes were: 0-30 cm height, 30-122 cm height, and 122 cm height to 2.h cm dbh. Basal areas were calculated using published tables (Avery, 1967). Animals. Primary mammalian species observed on the field plots were the short-tailed shrew (Blarina brevicauda), white-footed mouse, and eastern chipmunk (Tamias striatus). Numerous other species of vertebrates were present on the plot at various times, but all were typical of the region. Species lists have been prepared for mammals 22 (Howell and Dunaway, 1959), summer birds (Howell, 1958), herpetofauna (Johnson, 196A), and insects (Howden and Crossley, 1961), which inhabit portions of the ORNL Reservation. Trapping was conducted prior to the study to determine normal populations in the forests. Trapping during the autumn of 1968 was very productive. Between August 29th and December 13th, a total of 905 trap nights produced 6A white-footed mice, A6 eastern chipmunks, 26 southern flying squirrels (Glaucomys volans), and 2 golden mice [Peromyscus (Ochrotomyg) nuttalli] for a total of 1A.1A animals/100 trap nights. The traps were located on trees at a height of 1.8 to 2.A m, using wooden shelves supported by metal brackets. A piece of rubber tubing held traps and shelter cans in place. All traps were baited with sunflower seeds and sufficient cotton for nesting material. The large number of white-footed mice captured on these shelves in- dicated that these nocturnal mice have no aversion to limited amounts of climbing, at least to a height of 2 m. This propensity for arboreal activity has been examined by several investigators (Hamilton, 19A1; Taylor and McCarley, 1963; Getz and Ginsberg, 1968). During selection of the potential study plots, a short series of live-trappings were undertaken in 1969 to determine postwinter relative abundance of small mammals. Two of the three field plots were sampled for eight nights using 25 traps placed near stumps, bases of trees, and other areas where small mammal activities were observed. Only 2 white-footed mice and l eastern chipmunk were captured in 399 trap nights during February and March, 1969, for a total of 0.75 animals/ 100 trap nights. The winter of 1968—69 was a poor mast year, and it 23 was Obvious that the granivorous mammals had practically disappeared. Due to the low populations, adults trapped in forested areas the previous autumn were introduced into these three plots in an attempt to restore the mouse populations to levels similar to those prior to the mast failure. Eleven pairs, and any of their unweaned juveniles, were released in nest boxes on each field plot in May, 1969. A total of 36 were released on the control, A5 on the live-trap, and 39 on the snap—trap plot. subsequent trapping revealed that 6 of these released adults were still living on each of the live-trap and control plots at the start of the field work. None of the juveniles were recaptured after their release. 2. Field Plot_Pr§paration and Techniques The three 1AO-m square forested plots were: 1) control; 2) live- trap plot; and 3) snap—trap plot. No additional food was placed on the control plot, which was used to examine only the populational changes in mice and shrews. Both remaining plots each received A35.2 g of radioactive seed at weekly intervals for 58 weeks. The live—trapping plot was trapped periodically to examine uptake, equilibrium, and ex- cretion characteristics of small forest mammals, as well as populational changes. The snap-trap plot was trapped seasonally, using Museum Special snap-traps to obtain animals for tissue analyses. All three plots were located along the crest of Chestnut Ridge in Roane County, Tennessee, on the Atomic Energy Commission Reservation. In relation to Building 2001 at ORNL, the control plot was located 2.96 km on a bearing of S8AOW; the live-trap plot was located 2A 1.35 km on a bearing of N36°W; and the snap-trap plot was located 2.51 km on a bearing of NA9°E. A distance of at least 2 km separated each plot so that movement of small mammals between plots would be unlikely. All plots were located with a transit, and a 10-m grid was established within each plot. Relative elevations were computed for each surveyed point. Forty-eight percent of each grid was established with a maximum allowable closure of :_l m. Remaining grid points were located by taping between previously established transit points. All 225 grid locations on each plot were marked with aluminum stakes and numbered in a two-dimensional array code (e.g., Station 1-1 to 15-15 in Fig. 2). Nest boxes were designed and installed on each plot at stakes with "even-even" numbers (Fig. 2 and 3). The purpose of the nest boxes was to provide ready access to seed caches and to potential litters born on the plot. These nest boxes were constructed of white oak, with two compartments (15.2 x 15.2 x 15.9 cm for the nest compartment and 7.6 x 15.2 x 15.9 cm for an entrance chamber), a marine plywood overhanging roof (30.5 x A0.6 cm and removable), and an 18-kg concrete block to prevent movement or raiding of the boxes by predators. Feeders were installed at "odd-odd" numbered grid locations (Fig. 2 and A). These feeders were constructed from clear plastic boxes (17.1 x 12.1 x 6.0 cm) modified by melting six 2.2-cm entrances in all four sides, with a plastic dish (A.1 cm dia. x 1.3 cm depth) glued near the center of the bottom. Abbott (1961) used wooden 25 O FEEDER AND ALUMINUM STAKE x NESTBOX AND ALUMINUM STAKE O ALUMINUM STAKE 4 3 102 LIVE TRAP ROTATION SEQUENCE 1-1 STATION NUMBER N a N N u-D N ‘ N 9: (i 0‘: 010203040 LIIII meters Figure 2. General layout of the live-trapping field plot, indicating trapping patterns and locations of nest boxes and feeders. Figure 3. I Nest box, Sherman live-trap in protective metal can, and aluminum stake used on the live—trap area. High-density concrete block on cover of nest box used to prevent disturbance by large mammals. .mmmohow mo maflp pm mooom omdoz .mdmoodoa mSUmNEOHom an msflaaoflm powwoflocfi mpsmsmmhm doom cum .nmflw oHpmmHQ opp Sosa Uo>osog ohms mcoom opp mo pmoz .oomam aw pmoa mpoMoHB 09H: can .©o>osoh Ahopqoo gopv wag .mwohm @Hofiy opp so meowm mafia mcfiwhsnmflc mom wows powwow .2 ohdwflm 28 feeders which concealed mice from view, and recorded 50% consumption of seeds within them. For this study, removal and storage of pine seeds was desirable. It was assumed that these secretive mice would remove seeds rather than consume them within the clear plastic feeders. Seeds were placed in the dish to prevent soaking by precipitation and to reduce the loss expected from larger mammals reaching through the entrances. These entrances were designed to allow access only to animals smaller than about A0 g in whole- body weight. Holes were drilled or melted in the dish and corners of each box to allow for drainage of liquids. All feeders were pinned to the ground with lO-gauge galvanized wire "wickets" to prevent disturbance by larger mammals. This feeder design was field-tested during autumn, 1968. White-footed mice used the feeders, but A of 6 feeders were chewed sufficiently by larger mammals to allow access to chipmunks and gray squirrels (Sciurus carolinensis). This problem occurred only during the mast failure in 1968-69. Seeds were dispersed at 7—day intervals in 6A feeders on the live-trap and snap—trap plots. Total weight of seed per plot was A35.2 g per week, or 6.8 g per feeder. All seeds were weighed the day before being placed on the plot, and were stored in numbered containers (A.A x A.A x 1.6 cm) for transportation to the plots. All unused seeds in feeders were removed from the plots each week, feeders cleaned, the next week's seeds placed in the dish, and then the feeders were repinned to the ground. Records were kept of the estimated percent of seeds completely removed from the feeders, and 29 the percent of seeds eaten in feeders. These percentages were estimated to the nearest 25% for each feeder. Mammal populations were live-trapped periodically on the control and live-trap field plots. Trapping during the winter was restricted to those nights when the predicted minimum temperatures were above 0 C. Sherman live-traps (8 x 9 x 30 cm) protected by shelter cans (11 x 11 x 30 cm) were used, with each trap rotated through one of four locations each trapping period in an attempt to reduce re- captures of trap-prone individuals (Fig. 2). Each trapping period was of two nights duration on each plot, with the second night on the control plot concurrent with the first night on the live-trap plot. Trapping on the live-trap plot was during the two nights prior to the next feeding of pine seeds, and this fixed trapping time served to normalize sampling times for comparison of radioactivity between trapping periods. Traps were baited with a few sunflower seeds on the trap door, with cotton batting and sunflower seeds provided in the rear of the trap. Traps were usually set after 1800 hr and run at about 0700 hr. In an effort to reduce shrew mortality in the live-traps, mouse meat was given to captured shrews as the traps were run in the mornings. Shrews were given water until refusal each time they were handled in the laboratory. All captured animals were brought to the laboratory, identified, counted for radioactivity, weighed, sexed, toe-clipped, reproductive status noted, and, with a few exceptions, returned the same day to the point of capture. 30 E. Radioactivity Determinations All animals were counted for radioactivity in a AOO-channel Packard pulse-height gamma-spectrometer (Fig. C—l), coupled to a single sodium—iodide crystal (7.6 cm dia. x 7.6 cm depth, Tl activated). During counting, animals were confined in plastic vials (3.2 cm dia. x 7.6 cm depth) lined with blotter paper, with air holes melted into both ends of the vials. Each vial was inserted into a second plastic dish (8.A cm dia. x 3.3 cm depth) which was then placed on top of the crystal (Fig. C-2). This procedure was necessary to control geometry of the animals with respect to the crystal during counting and thereby reduce variance of the measure- ments. Animals were counted for up to a maximum of 20 min. depending upon radioactivity levels. Isotopic standards were prepared from aliquots of each isotope saved for that purpose. These standards were contained in 30-ml Nalgene bottles, which were filled with 20 ml of distilled water and placed in vials like those used to hold animals. A11 radio- activity analyses were based upon these standards. Radioactivity of the standards was determined in a gamma ion chamber by the Analytical Chemistry Division (ORNL). Corrections for background and physical decay of the isotopes were made, and all data were converted to disintegrations per minute (dpm). All animal tissues, excretory products, insects, and individual seeds were counted in a similar system, with the following changes. Tissues were oven-dried at 50 C and then placed in test tubes (25 x 31 150 mm) for counting. The Packard analyzer was coupled to an automatic sample changer with a well-type crystal. Standards for these analyses were prepared by drying the isotopic solution onto small sponge cubes, which were then placed in test tubes. Output from both of these Packard systems was in the form of paper tape, which was then converted to magnetic tape for computer analysis by the RESAP program (Brooks gt_§l,, 1970). This program utilized a least squares analysis to reduce gamma spectra to estimates of radioactivity contained in the samples. The computed estimates served as the basic radioactivity data used throughout the study (Appendix C). F. Statistical Procedures Basic statistics were used for obtaining treatment combination means and confidence intervals (Snedecor, 1956). Threeéway or four- way factorial analyses of variance (Hull, 1967) were used to determine significance of the treatments and interactions at isotopic equilibria 137 in the mice. Significant variables from the Cs analysis were em- ployed in a predictive equation using a multiple linear regression program (Van Dyne, 1965) modified by Sollins (1971). Uptake and retention curves are generally considered as reflective of the differential movement of isotopes into and out of various body pools or organs. Thus analyses for these wholeébody curves are combinations of exponential accumulation or decay components using either linear regression analyses for each separated component ("stripping" each linear segment from the curve until the final 32 component is linear), or nonlinear regression analyses of the entire curve. The "stripping" technique has been severely criticized by Van Liew (1962), who found that multicomponent curves would reduce to three-component, and occasionally, four—component models through stripping the curves. The nonlinear approach was used in this study to avoid subjective judgment of each component, although some problems still existed. Uptake curves were analyzed by two-component models of the form: where At = radioactivity at time t, Qe = equilibrium body burden, a1 = radioactivity participating in the first component, A1 = elimination rate coefficient of the first component, a2 = radio- activity participating in the second component, and A2 = elimination rate coefficient of the second component. Retention curves were analyzed by three-component models of the form: A = a e Alt + a e Agt + a e A3t t 1 2 3 ’ where a3 = radioactivity participating in the third component, and A3 = elimination rate coefficient of the third component. Both of these equations were analyzed with a nonlinear least squares program written by Goldstein (1971). Computer analyses were performed on an IBM 360/75 or 91; RESAP computer analyses were performed on IBM 7090 or 7091 models. IV. RESULTS A. Seed Consumption and Radionuclide Turnover by_White-footed Mice ig_the Laboratory 1. Food Base 137 Uptake and distribution of Cs and 60Co in white pine seeds was followed throughout the soaking and leaching procedures (Fig. 5). 137 The seeds acquired 62% of the Cs and 7A% of the 60Co during the soaking procedure. Uptake of 137Cs during the soaking procedures occurred between 5 and 10 hr and decreased after that time; 60Co was primarily taken up between 20 and 30 hr of soaking (Table B-l). 137 The indication of a doubling in Cs radioactivity between A5 and A8 hr had not occurred previously through 96 hr (Appendix A), and probably was a result of sampling error. The acid-leaching and rinsing procedures reduced the concentration in the seeds to r 1370s and 21% for 6000 of the initial soaking solution. 19% fo The acid leach did not remove as much 60Co as expected, but this was thought to be due to the much greater concentration of 60Co in seeds compared to that used earlier. Distribution of isotope between the seed coat and endosperm was determined by counting 100 undamaged endosperm shelled by white- footed mice during the laboratory study. Mean endosperm concentrations 137 A were A.70 :_2.30 x 103 (dpm :_l S. E.) for Cs and 2.99 i_2.17 x 10 33 3A SOAKING SOLUTION WASTE SOLUTION '37Cs 71.007 ’ 1370s 26.944 6OCO 554.346 6006 145.229 SEED UPTAKE AT 46 hr ACID-LEACHED SOLUTION '37Cs 44.063 ’ '3705 26.749 6000 409.117 50011 243.426 ACID-LEACHED SEED AT 2 hr OISTILLEO WATER RINSE 1370s 15.314 ' ””011 1.914 5000 165.691 5°06 46.651 FINAL RINSEO SEEO SEED COAT ‘37Cs 13.400 W ‘3705 52‘s 6000 116.640 5000 70.579 ENDOSPERM ‘37Cs 6.164 6°00 46.261 137 Figure 5. Flow diagram for location and distribution of Cs 60 and Co during Pinus strobus seed-soaking procedures; values are mCi. 35 5 137 6 for 60Co (dpm/g was h.35 :_2.08 x 10 for Cs and 2.76 i 2.00 x 10 for 60Co). Endosperm comprised 59.A% of the seeds' weight, 61.1% 137 60 137 of the Cs, and A0.6% of the Co. The correspondence of Cs to weight does not indicate equal availability of the isotope from both endosperm and seed coat, due to the acid-leaching procedure 137 Cs from the seed coats. The influence 137 removing readily-available of consumed but unassimilated Cs and 60Co contained in seed coats appeared to be minimal due to this acid-leaching procedure (Appendix A). At the end of the field study, a germination check was made using both radioactive and uncontaminated seeds (100 seeds each). In 60 days, 60% of the controls had germinated, compared to 0% for radioactive seeds. The radiation dose received by the radioactive seeds during the study was not determined exactly, but an estimation was made of 30 rads/day for combined beta—and—gamma dose from both in- ternal and external sources. At the end of the study the accumulated dose was approximately 12 krads. The LD5O for seeds of several pine species has been reported to range from 5-15 krads (Osborne and Lunden, 1961) for acute irradiation. Chronically-irradiated seeds apparently have a higher LD50 (Mergen and Johansen, 196A). Thus the nongermination of tagged seeds during the study may in part have resulted from excessive radiation and/or a combination of the procedures used to tag the seeds. No germinated seeds were observed on the field plots during the study. Feeding rates for mice in the laboratory were summarized for 190,A70 pine seeds (mean seed weight = 18.25 mg air—dry) used 36 during the laboratory study (Table B-2). To determine whether numbers or biomass of seeds should be used in further analyses, mean weekly weight per seed was examined in a threedway factorial analysis (Table B-3). Both feeding rate and temperature were significant as well as the interaction between these two variables. Therefore, it was decided that weight of seed fed per unit time would be used in further analyses. Time (or week fed) was not significant, and analyses concerning uptake characteristics for each treatment combination through the A9-day uptake period would not require consideration of weight of seed fed. 137 60 2. Equilibrium Body_Burdens 2£_ Cs and Co 137 Equilibrium body burdens for Cs and 60Co in white-footed mice were highly correlated with the seed ingestion rate (Table 1). Effects of sex and temperature were also observed, with higher equilibria in females and in both sexes at higher temperatures. 137 Equilibrium for Cs occurred within the first 15 days of uptake in mice. Theoretically, equilibrium body burdens should be the asymptote of uptake curves for each radioisotope during chronic feeding. To avoid problems associated with analyses of nonlinear data, the uptake period prior to equilibrium was excluded from this analysis. Data were normalized for variable live-body weights of the experimental animals through use of dpm/g values. The influence of the primary factors (sex, temperature, and feeding rate) and day of uptake were examined in a fourdway factorial analysis with the goal of eliminating day of uptake as a factor. 37 Table l. Equilibrium of 137Cs and 6000 in Peromyscus leucopus during chronic ingestion of Pinus strobus seeds for A9 days.a Ingestion .2 lg_ 59_ 399. Mean Rate:b Temperature Radioactive Equilibrium (dpm X 103/g) (C) 137Cs: Females A.A 0.80 3.97 20.AA 53.56 19.69 10.0 0.9A A.26 21.02 56.32 20.63 15.6 0.79 A.AO 33.16 61.93 25.07 21.1 1.1A 5.98 36.55 81.A1 31.27 Mean 0.92 b.65 27.80 63.30 2A.17 137Cs: Males A.A 0.58 3.3A 18.5A 36.65 1A.78 10.0 0.80 3.69 2A.8A AA.59 18.A8 15.6 0.77 A.50 2h.02 59.98 22.32 21.1 1.36 3.70 28.16 65.52 2h.69 Mean 0.88 3.81 23.89 51.68 20.07 6OCo: Females A.A 0.A8 2.89 15.27 56.39 18.76 10.0 0.53 2.27 18.38 57.A7 19.66 15.6 0.35 3.11 21.83 51.81 19.27 21.1 0.A2 2.8A 29.A1 76.1u 27.20 Mean 0.A5 2.78 21.22 60.A5 21.23 6OCo: Males A.A 0.5A 2.A6 15.79 hh.25 15.76 10.0 0.A6 2.32 17.72 68.68 22.30 15.6 0.36 2.57 15.15 67.0u 21.28 21.1 0.88 2.A3 15.71 A3.60 15.66 Mean 0.56 2.A5 16.09 55.89 18.75 -: - - _____- aStandard errors given for both sexes combined during chronic ingestion in Tables B—33 through B—AO. bIngestion rate = number of seeds ingested per day. 38 The first analysis, including day 8 of uptake, resulted in a significant effect for day of uptake, which indicated that mice were not at equilibrium.by day 8. The data were then run without day 8, but including all data between days 15 and A9 of uptake. Day of uptake was eliminated as a significant variable with deletion of day 8 from the analysis. Subsequent uptake by long—term com— partments (e.g., hair and bone) apparently was minimal compared to the soft-tissue body burden, and prObably was masked by normal variation in the data. 137Cs dpm/g indicated the The four-way factorial analysis for primary importance of feeding rate over any other variable (Table B-A). Other variables which were significant were temperature, sex, and three interaction terms. These interactions were: (sex X temperature), (temperature X feeding rate), and (sex X temperature X feeding rate). Results for 60Co dpm/g confirmed all significant relationships above, 137Cs (Table B-5). One 137 but generally, to a lesser extent than for interaction term, (sex X feeding rate), was significant for Cs but not for 60Co. 137 Variables which were significant in the Cs factorial analysis were used in a multiple linear regression model for later correlation with the field data. To avoid problems with nonindependence of six successive measurements made on the same mouse, only the mean equi- librium body burden was used in this regression. As in usual practice in handling radioactivity data, the variance nonhomogeneity (variance was proportional to count rate) was corrected by transforming all dpm/g data to natural logarithms (1n) before analysis. The overall 39 regression was significant, but individual degree-of—freedom regressions indicated that only the feeding rate and those interaction terms in— volving the feeding rate made significant contributions to the total regression (Table B-6). The r2 for the total regression was 0.98A. Maximum deviations from the model ranged from -0.53 to +0.A8, with a standard error of estimate of i_0.21 (Fig. B-2). In terms of number of seeds, the reliability of this technique at an ingestion rate of 50 seeds per day was :_13 seeds. Thus there was a good 137 correlation between ingestion rate and Cs equilibrium level in white-footed mice under laboratory conditions. 3. Internal Radiation Dosages Potential internal radiation insult from beta— and gamma- 137 emitters was estimated for the maximum Cs and 60Co body burdens in white-footed mice. The maximum radioactivity acquired by mice 137CS from either the laboratory or field was 18A,AOO dpm/g for and 92,0AO dpm/g for 60Co. Based upon computational procedures described by DiGregorio gt_al, (in press), the maximum beta—plus- gamma dose rate experienced was 1.5 rads/day. The maximum time span for contamination at this level was A05 days. Thus the maximum dose should not have exceeded 600 rads during the study. The LD50—3O for an acute gamma—irradiation was 1,070 rads for the white-footed mouse (Dunaway gt_§l,, 1969). A radiation dose is less effective when delivered chronically rather than acutely, and early radiation mortality was not likely in either the field plots or the laboratory. Based upon results of French §t_§l, (1969), possible effects of the A0 radiation doses in this study might have been a shortening of life span and reduction in fertility, but no evidence of such effects was Obtained in this study. 137 60 A. Parameters for Chronic Ingestion.gg: Cs and Co Each 137 Cs treatment combination was averaged for each day of uptake from day 1 through day A9 before analysis using a two-component exponential equation (Fig. 6 and Table B-7). There appeared to be 137 a correlation between equilibrium body burden of Cs and temperature, but only slight changes in the other parameters were observed. The elimination rate coefficient for the first component also appeared to follow a fairly consistent trend with changing temperature, with a more rapid clearance of radioactivity at lower temperatures. There was no obvious trend between the allocation of radioactivity to each component, except for a general statement that the first component was larger than the second. The first component apparently reflected a rapidly-clearing compartment, often considered to be the gastro- intestinal tract contents (Orr, 1967; Kitchings gt_§l,, 1969). But 137Cs has such a high assimilation from the gastrointestinal compartment into the blood (ICRP, 1960), that this first component appeared to be a combination of the unassimilated fraction in the gastrointestinal tract plus some of the more rapidly-clearing body pools. The gastrointestinal tract was essentially clear after 6A hr, based upon the fecal radioactivity analysis (Fig. A-6). This clearance time was converted to a rough estimate of the gastrointestinal clearance rate by assuming that five biological half-lives, or '37Cs WHOLE-BODY RADIOACTIVITY (dpm/q) A1 seeds/day 0 SUMMER A SPRING A AUTUMN 0 WINTER 6 42 18 24 3O 36 42 48 54 TIME (days) Mean accumulation of 137Cs in Peromyscus leucopus at sixteen treatment combinations of temperature and chronic ingestion of Pinus strobus seeds. Each point represents the mean of six mice. Winter = £1.11 0; autumn = 10.0 0; Spring = 15.6 C; and summer = 21.1 C. Data from Tables B-33 through B—36. A2 clearance of 96.9% of the total radioactivity, occurred within this 6A-hr period. By division, this biological half—life should be approximately 12.8 hr and.can be converted to an estimated elimination rate coefficient by the following relationship: _ 0.693 Tb - Ab , where T = biological half-life, and l = biological elimination rate b b coefficient (equivalent to A1 of the uptake equation). Solving for (lb) gave a value of -l.30 for the gastrointestinal compartment. Computer-derived values for the first component averaged -0.A8. Thus the computer—derived first component apparently included more than just the gastrointestinal tract clearance. This component seemed to reflect a continuum of excretion rates from a combination of body pools. Variability of the data was too great to attempt derivation of a three-component model. A main objective of this work was to determine seed consumption 137Cs from the rates by mice. The equilibrium body burdens for laboratory were subsequently plotted against the ingestion rate (Fig. 7). This curve appeared to be leveling out at high ingestion rates, and was subjected to a nonlinear analysis to determine the asymptote of the equilibrium curve. This asymptote should represent the ad libitum ingestion rate under laboratory conditions, and was calculated as 19A seeds per day, or 3.5A g/day. This relationship appeared to be a reliable method for estimating seed ingestion rates 137 from a readily-measured parameter, the body burden of Cs at equilibrium. 1O5 3 \ E 2 Q 3 S 104 a: CD 2 3 5 LIJ (I! .9 12 2 103 5 0 Figure 7. A3 SUMMER (21.I°C) SPRING (156°C) AUTUMN (100°C) WINTER ( 44°C) I5 30 45 60 75 90 105 NUMBER SEEDS EATEN PER DAY Mean equilibrium of 137Cs in Peromyscus leucopus as a function of ingestion rate and temperature in the laboratory. Data are equilibrium values from Table B-7. AA Uptake of 60Co could not be fitted by computer analysis, apparently due to the large variability in the data. The only analysis for 60Co appears in Table l, and represents the mean radioactivity between days 15 and A9 of uptake. Similar trends 137 were apparent for 60Co as were reported for Cs, but there were more exceptions between temperature levels. This was expected due to the mode of excretion of 60Co and the problems associated with fecal excretion as mentioned earlier. 137 60 5. Parameters for Retention 2: Cs and Co After Chronic Ingestion Daily retention means for mice, after cessation of chronic ingestion of radioactive seeds, were analyzed for each treatment 137 combination by a nonlinear three-component model for both Cs dpm/g and 60Co dpm/g (Tables 2 and 3, respectively). Results from 137 the Cs analysis indicated rather consistent but small changes in most of the retention parameters, with the elimination rate coefficients more closely correlated to temperature than feeding rate. Most of the treatment combinations indicated the presence 137 of a small first component for Cs, whereas the elimination rate coefficient for this component was less consistent. Both the second and third components for each feeding rate were generally reduced by lowering the temperature, although the effect was small. The 137 mean biological half—life for Cs was 0.6 days for the first component, 3.5 days for the second, and 20.9 days for the third 137 component. Based upon the whole-body burden of Cs after A9 days of chronic feeding, 1A% was excreted in the first component, 82% in A5 Table 2. Retention parameters for 137CS in Peromyscus leucopus after chronic ingestion of Pinus strobus seeds for A9 days. Ingestion rate number of seeds ingested per day. 1 t 1 t 1 t Equation is At e l + a2 e 2 + a3 6 3 . Ingestion Temp Parameters of the Retention Equation 61 A1 a2 A2 a3 1 Rate (0) (dpm X (day-l) (dpm x (day'l) (dpm x (day‘l) 103/g) 103/s) 103/e) 2 A.A 0.05 -1.268 0.58 -0.28h 0.0A -0.0A15 10.0 0.18 -0.78A 0.85 -0.207 0.05 -0.03A6 15.6 0.23 -0.8A9 0.66 —0.189 0.02 -0.027A 21.1 1.22 -0.271 0.09 —0.089 0.02 -0.0165 10 A.A 1.22 -0.68A 2.63 -0.225 0.11 -0.0267 10.0 1.33 -0.578 3.76 —0.198 0.09 -0.0217 15.6 2.A8 -0.311 1.73 -0.1A7 0.07 -0.0160 21.1 0.30 -2.127 A.73 -O.159 0.13 -0.0221 50 A.A 3.17 -1.911 16.63 —0.219 0.6A -0.0308 10.0 5.29 -1.250 20.96 -0.188 1.61 ~0.0A57 15.6 1.A9 -1.222 25.08 -0.177 1.93 -0.0A11 21.1 3.02 -1.99A 27.A2 —0.155 1.28 -0.0323 100 A.A 1.7A -1.870 5A.83 -0.251 2.59 —0.0A32 10.0 1.99 -2.195 56.06 -0.2A9 1.A2 ~0.03A9 15.6 5.72 —3.2A5 5A.A1 —0.180 1.51 -0.0265 21.1 10.A8 —1.111 63.58 -0.1AA 1.03 -0.0187 Mean: % 1A.00 82.13 3.82 Ti —1.091 -0.198 -0.0332 :,1 S. 3.06 0.3A0 2.76 0.007 0.52 0.0027 A6 Table 3. Retention parameters for 0Co in Peromyscus leucopus after chronic ingestion of Pinus gtrobus seeds for A9 days. Ingestion rate number of seeds ingested per day. Alt lgt 13t Equation is At e 2 e a3 6 . Ingestion Temp Parameters of the Retention Equation Rate (C) al A1 a2 12 a3 13 (dpm X (day-l) (dpm X (day'l) (dpm X (day‘l) 103/6) lO3/g) 103/6) 2 A.A 0.36 -l.718 0.05 -0.099 0.02 -0.007A 10.0 0.A2 —1.338 0.06 —0.076 0.03 -0.00h3 15.6 0.38 —1.785 0.05 -0.115 0.02 -0.0066 21.1 0.38 -2.160 0.06 -0.l51 0.03 -0.0060 10 A.A 2.03 —1.732 0.25 -0.107 0.1A —0.0111 10.0 A.01 -1.A36 0.29 -0.086 0.16 —0.0076 15.6 2.A0 -1.896 0.3A -0.071 0.15 —0.00Ah 21.1 2.69 -1.9A2 0.2A -0.102 0.15 -0.0105 50 A.A 1A.98 -1.571 1.2A -0.11A 0.8A -0.0121 10.0 21.06 -1.635 2.05 -0.188 0.93 -0.0120 15.6 19.52 -l.858 1.00 -0.08A 0.67 -0.009A 21.1 18.36 —2.A1A 1.32 -0.079 0.92 -0.0098 100 A.A 61.85 -2.10A 3.25 -0.139 2.16 -0.0122 10.0 60.AA -1.A26 13.39 -0.299 2.97 -0.0136 15.6 A6.12 -1.9A9 3.73 -0.108 2.A5 -0.0100 21.1 A3.99 -1.801 A.77 -0.16A 3.15 -0.0100 Mean: % 86.65 8.28 A.99 xi -1.795 -0.13A -0.0110 1,1 3. E 2.09 0.090 1.08 0.036 0.6A 0.0021 AT the second, and A% in the third component. Whereas 6OCo could not be fitted to the uptake equation, retention of this radionuclide was readily fitted by a three- component model. But there was little correlation of 60Co retention parameters to either temperature or feeding rate. The mean biological half-life for 60Co was 0.A days for the first component, 5.2 days for the second, and 63.3 days for the third component. The fractions of the total body burden excreted in each component were 87%, 8%, and 5% for each successive component. 137 Thus, it appeared that excretion of Cs and 60Co was not greatly influenced by temperature or feeding rate in white-footed mice following chronic feeding. 137 6. Effect g£_Mode 9: Entry 9Q_Retention 2: CS The lack of an obvious influence of temperature or feeding rate 137 on elimination of Cs prompted a comparison of this data with the results of other investigators. 137 Retention of Cs was examined in white-footed mice by Baker (1970) with no significant differences in retention, for the long-term component, attributable to temperature or confinement. It should be pointed out that he dealt only with day 6 through day 33 of retention, and used intraperitoneal injection of the isotope. He concluded that the early component of excretion, prior to day 10, was significantly correlated to metabolism, based upon projected intercept values for that component. A comparison was made between Baker's data for injected mice and my data for chronically-fed mice (Fig. 8). The 9 C 100 SO 20 10 UI ‘37Cs RETENTION 1%) N 0.5 0.2 0.1 Figure 8. A8 A CHRONIC FEEDING o INJECTION 5 10 15 20 25 30 35 40 TIME (days) Retention of 137Cs after intraperitoneal injection and A9 days of chronic feeding of Pinus strObus seeds. Injection data from Baker (1970), with permission to use unpublished data. Mean temperatures: injection = 22 C; chronic = 12.8 C. Data from Table B-8. A9 difference in temperature should have resulted in faster excretion in the chronically-fed mice, if temperature was the overriding factor. As excretion was slower in the chronically-fed mice, the differences apparently are not an indication of temperature changes, but a reflection of inherent differences in isotOpic behavior between injected and chronically—fed mice. 137 As there was no other comparable information concerning Cs in white-footed mice, or other small cricetids in the literature of which I am aware, data for an extensively studied and similarly-sized murid (the laboratory mouse, Mus musculus), was compared to the data for this study (Table A). Laboratory mice are slightly larger than white- footed mice and, based upon Richmond's (1958) work, should have a 137 greater retention of Cs. In fact, the converse was apparent, with the data for the white-footed mouse indicating a greater retention than observed in the laboratory mouse. One study did approximate my data between days 8 and 22, and was a chronic-intake study which used the tagged drinking water technique. The length of time that a study is conducted affects the resultant values derived by the three—component excretion equation. One laboratory mouse study was of 57 days duration, with the remaining two studies terminating at approximately day 37 and 38 of excretion. Although I extrapolated the data by three-component equations to day 100 (Table A), the data cannot be adequately extrapolated beyond the termination of each experiment. For example, Richmond gt_§l, (1962) Show a consistent divergence after day 27, with the actual data indicating a greater retention than predicted by their equation, 50 Table A. Effect of mode of entry upon l370s retention in Peromyscus leucopus and the laboratory mouse (Mus musculuS). —: L Day of 1370s Retention (%) Excretion P. leucopus M;_muscu1us Chronic Chronic Acute Acute Oral Ora Injection Injectioa Food Water Saline Saline 0 100.00 99.89 100.00 99.90 1 75.67 57.77 53.03 60.59 2 60.h6 Ah.13 35.77 AA 0A 3 A9.72 36.98 27.16 3A.93 5 33.86 27.51 17.6A 2A.02 8 19.57 18.16 10.18 1A.63 15 6.67 7.29 3.61 5.29 22 2.89 3.09 1.55 2.15 29 1.83 1.3A 0.71 0.93 36 1.19 9452? 0.3A 0.111e A3 0.96 0.26 0.16 0.18 A9 0.80 0.13 0.08 0.09 57 0.A5 0.05 0.011e 0.0h 71 0.32 0.01 0.008 0.007 85 0.26 0.002 0.002 0.001 100 0.21 0.000A 0.000A 0.0003 8‘From this study, terminated on day 100 of excretion. bFrom Richmond.gt_gl, (1962), terminated on day 37 of excretion. cFrom Richmond (1958), terminated on day 57 of excretion. dFrom Furchner and Richmond (1963), terminated on day 38 of excretion. eValues after line are extrapolations from authors' data. 51 usually indicative of the presence of another component in the equation. Another difference in retention occurred during the first 8 days of excretion, when chronically-fed white-footed mice had a much greater retention than injected laboratory mice. This difference in retention apparently reflected the mode of entry into the animal. Injected mice showed a more rapid excretion during the first few days than chronically- fed animals. Thus, it appeared that the curves between and within these two species were not consistent, probably due to differences in the mode of entry into the animal. f Uptake and Retention 2£_l37Cs —— _— 7. "Mirror Image" Respective parameters for uptake and retention data varied considerably, even for the same treatment combination. This prompted an examination of the chronic uptake curve superimposed over the inverse of the retention curve (Fig. 9). Although the apparent differences between the two curves were not great, it is clear that the gastrointestinal compartment acquired radioactivity more rapidly than expected from the inverse of the retention data. The differences were more apparent when subjected to computer analysis. Both curves were analyzed by the same two-component uptake equation with the following results: At = 98.69 - 11.08 6"1'SOOt - 87,59 e-O'196t, for excretion, and A = 100.38 _ 69.66 e'O-h75t _ 30.70 e-0.06At, t for uptake. The importance of these differences will be considered in the Discussion. 52 .coflp0hoxo sow : magma was .OMMpQS sow Elm OwaB 80pm Unmasmssdm spam .coprMoxo wcflhdc :w n z csm Oxmpmd mnwhsw mm H z .sowpwhoxo mo o bed 80am coflpcopos & I Sooa moms woman memo OOHpogoxw mwooa u hpfl>flpow0fivwh on how no woman 0>Hso waspmb .mcoom munchpw macaw mo soapmomsfl canoano mhww m: hopmw was mzflndu mmmmmmmw.mmmmxmmmmm sfl sofipohoxw was oxmpmd mopmH mo :mwwsfl hospflzz .m whsmflm .963 £5 .66 we 1. ow on ~n 8 mm ON 9 N. m w o «owm..o '0 ”mm N0 I «000.. '0 V00... Im0.mm H A ZOCVZMHMK o§| 00: ZO_PMKUXM 0 580.016 62.0... 1 Soto Io mom .3 I 9.1091 as 66 S .t main: 6 lNBDHBd 53 137 60 8. Ratio Between Cs and Co An extremely interesting and useful parameter found in this study was the ratio between the radioactivity of these two isotopes. For convenience, this will be referred to as the Cs/Co ratio and is a dimensionless number. This parameter had a characteristic pattern in white-footed mice fed chronically on tagged pine seeds (Fig. 10). 137Cs uptake pattern, During isotopic uptake, this ratio resembled the and increased up to a maximum of about 1.5 after A9 days of chronic feeding. The pattern after the first three days of excretion was more similar to the 60Co excretion curve and was still decreasing at 100 days of excretion. The immediate value of this parameter, for my purposes, was to enable a determination of elapsed time since the last ingestion of pine seeds. The cause of fluctuation in this ratio was the mode of 137 excretion of the two isotopes (Fig. A-5). Decrease of Cs was almost linear for the first 30 days of excretion, compared to a much more rapid decrease in 60Co, which created a very rapid peaking of the Cs/Co ratio during the first few days of excretion. As field animals were fed once weekly, versus the once-daily feeding in laboratory- maintained mice, the rapid fluctuation in this ratio during the first three days of excretion enabled determination of a correction factor for day of excretion in the field animals. Results of the Cs/Co ratio emphasized the differences in mode of 137 excretion for Cs and 60Co, and allowed a determination of the day of excretion for white-footed mice. 5A .mlm OHDOB Sosm sumo .vaOm mSQOMpm mscflm mo :oHpmomCH OflGOHQO 502 . ca 033 mzwo m: hmpmm was wswhdo mdmoOdOH mdomNEOMOm CH owpmn ooow\mo~.mH 1.963 m2: 8. om 8 9. on on 9. 0... ON 0. on on 8 o. 0 V (0 In 011w 0009/50“El mm 27.8 10.28 18.35 16.85 15.16 2.73 A.15 A.28 2.21 'Total 2A.96 29.A0 26.30 26.89 2.50 3.92 3.88 1.98 Number of 2.A—12.6 1,050 950 1,020 1,007 Trees/ha :62 :152 :125 :67 12.6-27.8 360 260 2A0 287 A5 37 37 2A >. 27.8 120 170 170 153 33 26 37 18 Total 1.530 1,380 1,A30 1,Ah7 87 131 125 66 Average > 12.6 22.73 25.83 25.35 2A.56 dbh (cm) :1.0A :1.60 :1.50 £9.79 Average > 12.6 20.A 20.1 22.5 21.0 Height (m) :9.5 :9.9 11.0 :0.5 Ground o-30aa 20.51b 23.57 39.39 27.82 Cover 30-122c 20.31 18.88 35.51 2A.90 (%) 122-2.A 21.8A 19.08 A3.67 28.20 aSize class by height in cm. bReplicated visual estimates of percent cover on 100 plots gave a S. E. of :_1.A% over all size classes. CSize class from 122 cm height to 2.A cm dbh. Tflfle8. Seasonal trapping summary of Peromyscus leucgpus, Blarina brevicauda, and Tamias striatus on the live-trap and control field plots. 61 Period or Total Total Captures Blarina Total Individuals Season Trap P.1. B.b. T.s. Total Mortality P.1. B.b. T.s. Total Nights (%) Live-trap plot Prestudy 2A0 10 6 1 17 0.00 5 6 1 12 Uptakea 8A7 28 37 3 68 5.A1 12 1A 2 28 Autumn 796 13 A8 A 65 10.A2 7 21 A 32 Winter 28A 13 26 1 A0 3.85 6 2O 1 27 Spring A50 20 20 3 A3 10.00 8 15 3 26 Summer A58 27 16 11 5A 0.00 9 11 6 26 Excretionb 512 A0 89 9 138 6.7A 23 37 5 65 Totals: 3,587 151 2A2 32 A25 6.61 A6 78 1A 138 Control plot Prestudy 2A0 6 A 0 10 50.00 A A 0 8 Uptakea 73A AA 23 6 73 27.27 8 12 2 22 Autumn 623 A3 21 1 65 23.81 12 13 1 26 Winter 335 13 1 0 1A 0.00 7 1 0 8 Spring A50 A9 0 0 A9 0.00 17 0 0 17 Summer A50 36 5 2 A3 0.00 8 1 1 10 Totals: 2,832 191 5A 9 25A 2A.53 32 26 3 61 Grand 6,A19 3A2 296 A1 679 9.83 78 10A 17 199 totals aPeriod from July 2A, 1969 to September 25, 1969. bPeriod from September 1, 1970 to December 10, 1970, on the live-trap plot only. 62 Table 9. Percent distribution of trapping effort and captures of Peromyscus leucopus and Blarina brevicauda at various field locations. Data summarized by period or season on the live-trap and control plots. Refer to Table B—l3 for captures per 100 trap nights. Period Live-trap Plot Control Plot or Trapping at: Trapping at: Season Feeder Nest Box Stakea Nest Box Stakea Trapping effort (%) Prestudy 53.33 0.00 A6.67 0.00 100.00 Uptakeb 30.22 20.66 A9.12 20.98 79.02 Autumn 32.16 17.59 50.25 19.10 80.90 Winter 33.80 19.72 A6.A8 25.07 7A.93 Spring 28.AA 21.78 A9.78 21.78 78.22 Summer 3A.9A 15.28 A9.78 21.78 78.22 Total: 33.30 17.53 A9.17 19.53 80.A7 Peromyscus leucopus captures (%) Prestudy 70.00 0.00 30.00 0.00 100.00 Uptakeb A2.86 28.57 28.57 3A.09 65.91 Autumn 7.69 23.08 69.23 39.53 60.A7 Winter A6.15 38.A6 15.39 53.85 A6.15 Spring 35.00 35.00 30.00 A2.86 57.1A Summer 29.63 22.22 A8.15 27.78 72.22 Total: 36.9A 26.12 36.9A 36.65 63.35 Blarina brevicauda captures (%) Prestudy 83.33 0.00 16.67 0.00 100.00 Uptakeb 51.35 2A.32 2A.33 17.39 82.61 Autumn 52.08 18.75 29.17 33.33 66.67 Winter 88.A6 0.00 11.5A 100.00 0.00 Spring 60.00 10.00 30.00 0.00 0.00 Summer 68.75 0.00 31.25 60.00 A0.00 Total: 62.09 13.07 2A.8A 27.78 72.22 aAluminum stake only, no nest box or feeder present. bPeriod from July 2A, 1969 to September 25, 1969. 63 Autumn captures of mice in the live-trapping plot were low despite the relatively large number of trap nights (Table B-13). It was felt that mice became trap-shy during this period, since signs of mouse activity were found on trap doors, but mice did not enter the traps. The trap-shyness hypothesis was supported by the capture locations during autumn, 1969 (Table 9). Mice appeared to be trapped in accordance with the proportional distribution of trapping effort during all seasons except autumn, when captures at feeder locations were much lower than expected. This was probably associated with the abundance of natural foods during this period, or possibly correlated to the increase in human activities on the plot. Trapping effort during the winter season was severely restricted due to low temperatures, and captures were low. The proportional distribution of captures returned to normal during this period. The shrew population on the control plot essentially disappeared during winter and had not returned by the end of the following summer. The cause for the shrew disappearance was not apparent, since I had good success in trapping shrews and keeping them alive. Out of 296 captures of shrews during this study, only 29 individuals were either found dead in the trap, or succumbed before they could be returned to the field (Table 8). Not all of these were victims of their metabolic demands or exposure, as 7 out of these 29 shrews were killed by the trap door closing on them. Four shrews were captured at least 12 times during 13 months of trapping (Table B—lA). And 20 shrews were captured two consecutive days without mortality. Such results were unexpected since many studies have reported high mortality rates 6A among captured shrews. The maintenance of a shrew population through winter appeared to be correlated with the availability of added pine seeds. Both the live-trap and snap—trap plots maintained high populations of shrews, as evidenced by trapping success and fecal remains in the feeders. Shrew captures on the live-trap plot were not in proportion to the trapping effort at various sites, but occurred twice as frequently as the trapping effort at feeder locations. Whatever the reason for the loss of shrews on the control plot, I do not believe that they were eliminated by trapping. No signs of their activity could be found during this period on the control plot. 3. Disappearance p£_Pine Seeds from Feeders The disappearance of seeds from feeders was estimated weekly during the field study (Fig. 11). A total of 18,713 g of seeds was removed or consumed in feeders on the live-trap plot compared to 23,622 g on the snap-trap plot. This represented 7A% utilization of the total available seeds on the live-trap plot and 9A% on the snap-trap plot (mean for both plots was 8A%). Collections of seeds from 330 feeders (containing whole seeds only) were brought to the laboratory after exposure on the plot for 7 days, and weighed to determine the error of visual estimates of feeder usage (Table B—l6). On the basis on each 25% class of feeder usage, estimates were within 0.3 g of actual weight. Offsetting errors in various use classes would reduce the total error of each weekly estimate, as the sum of all visual estimates was within 0.16% a) 0’ a) C) E2 ‘0 C) 8 a 8 E ‘1’ 3 :5 “<3 :9; :8: 3 .- 100) Uptake) Autumn A Winter ) Spring ‘Summer ‘ ./\ ' II . A 2 1. 80 v r: j I Z 9 A 2 60 v ' ' N 2 b\/ 21 p. D 40 _, 1 SNAP-TRAP: TOTAL UTILIZATION ,<_I 2 LIVE-TRAP: TOTAL UTILIZATION ,9 3 SNAP-TRAP: EATEN IN FEEDER 2° 4 LIVE—TRAP: EATEN IN FEEDER E5 a: 1.1.1 o 11.1 1.1.1 LL :2 2 E < 111 0 Figure 11. 13 26 39 52 TIME AFTER INITIATION OF STUDY (weeks) Weekly Pinus strobus seed utilization and ingestion in feeders by small mammals on the live—trap and snap—trap field plots. Data from Table B—l5. 66 of the actual weight. Another check was made during the third week of feeding. All uneaten seeds were separated from fragments of eaten seeds and weighed. The visual estimate of whole uneaten seeds was 235 8 compared to an actual weight of 2A2 g, or an error of 2.9%. It was felt that the visual estimates of weekly seed usage were within 5% of the actual values. Percent utilization of seeds rapidly increased during the uptake portion of the study (July 2A to September 25, 1969). Animals on the snap-trap plot consistently utilized approximately 20% more seeds than did animals on the live-trap plot throughout the year, with less than 100% utilization occurring only in autumn and winter on the snap-trap plot. A sign test was performed on the weekly trend of percent utilization during this period when populations on both plots utilized less than 100% of the available seeds. A (+) was assigned if utilization on both plots either increased or decreased the same week; a (-) was assigned if the trends differed. The result of this test was significant, indicating that both populations were behaving similarly in terms of percent utilization (Fig. 11 and Table B-15). Apparently an exogenous influence, such as weather, was acting on both populations so that if seed utilization changed on one plot, it also changed in a similar manner on the other plot. The overall greater utilization by the snap-trap population, however, compared to the live—trap population, indicated a higher population on the snap-trap plot. Percent of seeds eaten in feeders was also estimated weekly for both plots (Fig. 11). After the first two weeks, the amount of seeds eaten in feeders rarely exceeded 20% of the total amount utilized. 67 One noticeable and abnormally high period occurred during mid-April, 1970 on the snap—trap plot. At this time a new power line right-of—way adjacent to an established power line was being cleared. When the clearing and burning was closest, within a few hundred meters of the plot, the small mammal population was incremented by numerous pine voles, presumably from the old right-of—wayu A snap—trap period in March, 1970 removed more pine voles than any other species, and was the only time that this occurred on any of the field plots. Thus, pine voles apparently were consuming seeds in the feeders. In order to identify consumers, feeder remains were compared with seed coat fragments from granivores fed in the laboratory, using techniques of Fitch (195A) and Kangur (195A). In almost all cases, when a quantity of seeds was eaten in a feeder, the fragments were similar to seeds shelled by mice. In general, shrews apparently removed entire seeds from the feeders (also observed in the laboratory). Mice and voles either removed seeds or consumed them in the feeders (Fig. A). Evidences of shrew activities began to appear around nearly every feeder during the first month of the study. These included excavation of underground tunnels to the vicinity of, or under, feeders; formation of tunnels in the litter layer (Fig. 12); seed fragments similar to shrew shelling, which were detectable in the tunnels with a scintillometer; and fecal remains inside the feeders. The reduction in the amount of seeds eaten in feeders during the first few weeks of the study (Fig. 11) appeared to be correlated with the 68 .poam mwhplo>3 93. am Anita 80303 powwow m on. 206625 36.2% woaflmpnpaonm map mo 833306 wsflaogfi .NH 08mg . v 1‘ .0 . fin“. . .v ‘1 D: 901000 I.- 69 initiation and presence of shrew activities around feeders. The gradual increase in amounts of seeds eaten in feeders during the summer of 1970 reflected an increasing size of the mouse populations. C. Radioisotopip_Body_Burdens for Small Mammals ip_ep_0ak-hickorprorest 1. Body Burdens ip_White-footed Mice Background levels found in white-footed mice prior to the study 137 (sampled from March to July, 1969) averaged 2 dpm/g for Cs and 8 dpm/g for 6000. After feeding of radioactive seeds began on July 2A, 1969, mice rapidly acquired significant radioactivity ranging from 137 60 20 to 50 dpm X 103/g for Cs (Fig. 13). The Co data were more 137 variable than that for Cs in the field animals and were not used to characterize body burdens throughout the year. The seasonal l370s (Table B—17). pattern was similar to that of Mice continued to increase in radioactivity up to the maximum (125 dpm X 103/g) observed during the study near the end of September, 1969. Considering that mice in the laboratory equilibrated within 15 days at a specific feeding rate, it appeared that this 62-day period (from July to September, 1969) in the field would have been more than sufficient for these mice to have equilibrated also. As live-trapped mice continued to increase in radioactivity after the first 15 days, it was assumed that their diet was changing during this period to include an increasingly greater proportion of tagged pine seeds. After the end of September, 1969, mice rapidly decreased to 70 .PHIm Dandy. Sou.“ .6de .9308 cw covdaosw who: was ma swap whoa no.“ psmmoam 0000. 98m 8. nsoqx mfldswfirfiocfl EEO .mooom mdponum mafia wcfigmpaou 90.3 mama mahplonrwa 063 no ddddofironn newsman was a gap“ cornea mqflmmdhp Hum mop?” mo mocha. 3000.10.35? 502 .MH warm Ohm. mmm. w < .2 .3 E < 2 n. q. 0 Z O m < 3 1 S «o O o o O D M I In1 I ON 0 O m“ I o d 0. 3]. S . o 0+» M a Q o H . m n 1 O 1 O 3 o _ I I O@ 8 0 O I. «I 1‘ .A q 3 o I 0 II OW nnU . I I) II In. 0 0 MW e W q 00. W )I‘IIII I m d 4 M 02.0mm“. ommm + II )1) ON_ .D/ w>_.—.U>wmIm om1=<._.1._.mOIm < 4 1) No.5. DMHOOuImtIg o 1)) (I H 1 _ i 1 e . , L $02 71 137Cs, or less than half their approximately 50 dpm X 103/g, for previous equilibrium levels. This was observed for individual mice as well (Fig. B-3). Mean daily temperatures were decreasing during autumn, at the same time that a better-than-average mast crop became available on the ground. The effect of temperature, as determined in the laboratory, was not pronounced and did not appear to be sufficient 137 to create the large decrease in Cs equilibria. The decrease appeared to be correlated more with a change in food habits than to the effect of lowered temperature. A systematic examination of nest boxes was made on December 31, 1969, to determine if pine seeds were being cached on the snap-trap plot. Of A9 nest boxes examined, 2A.5% contained nothing, 1A.3% contained nesting material or mice, 2.0% contained remains of pine seeds, 67.3% contained hickory nuts, and A.1% contained acorns. The average number of hickory nuts was 11.1 per nest box used for storage (Fig. 1A). The prevalence of hickory nuts may have indicated either a preference by mice for these foods over any other available food, or removal of this food to locations where it could be more thoroughly worked. Storage of pine seeds had been expected, as clear plastic feeders were used in an attempt to encourage mice to remove and store pine seeds. It was probable that mice ate pine seeds at feeders or other adjacent feeding sites, rather than returning to nest boxes to consume them. Feeders were located a maximum distance from the nest boxes (1A.A m), and closer and more numerous escape avenues were revealed when mice were released near feeders and ran to nearby hiding places. 72 .mcwsono awowmhp msomm .eemp anus .xon pmm: one 90 pmcaoo pmmfia Momma Cw pmos Hawsm .wooom hmzoamcdm 30% m Sufi: Auscpmxoos 0cm pdsmamv .xop pmo: m cw m5MOozmH msowxmogom an OmSMOpm boom 0>oam :fl was haox0flm we own: who: mcmom amzoawcsm mpd: mp0MOfl£ hflpmoe mam muoom .# u. n... 5v .sa magmas 73 Wholeebody equilibria in mice continued to decline after the September, 1969 peak, to a low of 5 dpm X lO3/g for 137 Cs occurring in January, 1970. By April, consumption began to increase significantly above the winter minimum and had returned to approximately 90 dpm X 103/g for 137 Cs by the end of June, 1970, which was nearly equivalent to the levels of September, 1969. This maximum rate of ingestion continued until feeding was terminated on September 1, 1970. The snap-trap plot was used to sample animals through each season in order to determine distribution of the isotopes at equilibrium levels in mouse tissues. The total population of small mammals apparently was denser on this plot, based upon the 20% greater utilization of feeder contents. Trapping success was low in this plot until traps were placed at feeder locations near the center of the plot (Table B-l8). Thereafter, success was comparable to the live-trap plot, but I felt that the trapping success did not reflect the true population level, even though a total of 51 small mammals were removed from the 2—ha plot over the span of one year. Trapping success may have reflected a difference between the efficiency of live-traps compared to snap-traps. Of the 51 captures on the snap—trap plot, 7 snap-trapped mice were sampled for tissue distribution of radioisotopes to determine whether the contents of their gastrointestinal tracts contained a similar amount of radioisotopes as did mice sacrificed in the labora- tory (Table 10). Although the sample size was small, the agreement 137 of organ weight and Cs tissue distribution between laboratory and field was readily apparent (compare to Table 5). Cobalt-6O differed 7A Table 10. Distribution of oven-dry weight, 137Cs, and 6000 in organs or tissues of Peromyscus leucppus after chronic feeding of Pinus strobus seeds on the snap-trap field plot. Organ or N Weighta Radioactivity in Organ (% :_1 S. E.)b Tissue (%) 137Cs 6OCo Heart 6 0.6A 0.7A :_ 0.08 0.61 :_ 0.10 Liver 6 A.7A 5.02 0.58 11.65 1.56 Spleen 5 0.17 0.26 0.03 0.17 0.03 Kidneys 6 1.16 1.6A 0.1A 2.A6 0.22 Lungs C 6 0.95 1.12 0.18 0.6A 0.07 Muscle 6 0.63 1.09 0.10 0.22 0.06 Femur 6 0.55 0.35 0.0A 0.16 0.03 Brain 6 2.11 2.36 0.A3 0.27 0.0A Testes 2 0.77 1.99 1.67 1.06 0.91 Ovaries 3 0.08 0.06 0.02 0.16 0.11 Epidhbmfis 2 5.02 2.78 0.67 6.95 A.92 Urogenital 3 0.A5 0.31 0.20 0.30 0.06 Bladder 5 0.08 0.17 0.10 0.16 0.06 Skin 6 17.31 9.99 1.58 3.8A 0.37 Carcass 6 5A.38 60.91 2.52 18.9A 3.Al Stomach 6 1.03 0.57 0.15 0.76 0.09 Sm. intestine 6 0.5A 0.50 0.17 0.57 0.11 Lg. intestine 6 0.2A 0.17 0.05 0.A5 0.09 Cecum 6 0.21 0.21 0.06 1.10 0.A3 Gastrointestinal contents: Stomach 6 8.06 2.A9 0.50 11.90 7.A5 Sm. intestine 6 2.AA 3.79 0.61 A.02 0.99 Lg. intestine 6 1.15 3.03 0.78 7.05 1.63 Cecum 6 1.72 3.91 0.79 32.18 8.7A Totals: Tissue 6 86.6A 86.79 1.73 AA.86 6.00 Gastrointestinal contents 6 13.36 13.21 1.73 55.1A 6.00 8‘Body weight percentages from Table B—19. bPercent of Wholeebody radioactivity. cGastrocnemius muscle only. dResidual carcass after removal of the listed organs. 75 considerably in distribution between tissues and gastrointestinal contents. The diminution of 60Co in the gastrointestinal tracts of field animals indicated a dilution of radioactive food with a greater amount of uncontaminated food than found in the laboratory animals. This lower gastrointestinal concentration was also indicated by the Cs/Co ratio, which was slightly higher in the field than in the laboratory (1.99 and 1.50, respectively), meaning that more of the 6000 had been passed through the tract than for a comparable day of excretion in the laboratory. Mice captured from the live-trap plot had been excreting radio- isotOpes for one-half to one day longer than snap-trapped mice, although the interval between feeding and trapping was identical. This conclusion was derived from 15 recaptures of old resident mice on two consecutive days during a trapping period (Table B-20). Mean Cs/Co ratios were 3.A1 on the first day and.5.28 on the second day. This general trend was normally found during the first three days of excretion, and consisted of a decrease in body burdens of both radioisotopes, but an increase in the Cs/Co ratio. Thus, the mice trapped in the field were not at equilibrium, but at some point during the first few days of excretion, and their wholeébody radioactivity required correction before estimating seed consumption rates. To summarize, the white-footed mouse population had varying 137 body burdens of Cs, with a maximum of 125 dpm X 103/g occurring just prior to availability of the 1969 mast crop. Minimal body burdens of 5 dpm X 103/g occurred from January through March, 1970, and then increased to 90 dpm X 103/g through summer, 1970. Tissue 76 137 distribution of Cs was similar to that Observed in the laboratory, whereas 6OCo apparently was diluted in the gastrointestinal tract by consumption of other foods. The Cs/Co ratio indicated that mice were not at equilibrium when captured in the field but had been excreting radioisotopes for about one day. 2. Body_Burdens ip_Short-tailed Shrews A totally unexpected result of the field study was the high body burdens of radioisotopes acquired by the short-tailed shrew. Background 137 levels found in shrews prior to the study averaged 3 dpm/g for Cs 137 and 15 dpm/g for 60Co. Initial uptake of Cs occurred about two weeks later than in mice (refer to Fig. 13). This lag apparently was correlated to the period of time when shrews were extending their tunnel systems and locating feeders. A rapid increase from background levels up to 70 dpm X 103/g for 137 Cs occurred in mid-August, 1969, and body burdens continued to increase up to the maximum of 1A5 dpm X 103/g by the end of October, 1969. Winter levels of radioactivity fluctuated greatly and did not decrease drastically as did radioactivity in mice (Fig. B-A). In general, the body burdens averaged 70 dpm X 103/g for winter, spring, and summer without a great amount of variation. In comparison to the mice, shrews had lower body burdens in late spring and summer of 1970, and higher body burdens during autumn and winter. Cs/Co ratios were examined in 20 shrews captured twice during the two—day trapping periods. The mean Cs/Co ratio was A.OO on the first day and 3.98 on the second day (Table B-2l). These ratios 77 were similar to those Observed in mice (3.A1 on the first day and 5.28 on the second) but were more erratic, and shrews apparently had been excreting radioisotopes for several days. There were three potential sources of radioactivity for shrews: seeds, mice, and insects. To determine whether short-tailed shrews would consume pine seeds in the laboratory, a single treatment combination (22 C and 10 seeds per day) with four shrews was initiated in May, 1970 (Fig. 15). For comparison, mean uptake and.excretion of 137 Cs were plotted with the appropriate mouse data for the same treatment combination. The similarities in the uptake curve indicated that shrews did consume pine seeds. This was also confirmed by direct observation. Initial uptake proceeded more slowly in these shrews, primarily due to only two of the four shrews ingesting any seeds before day 3. By day 5 of uptake, shrews contained more 137 Cs than did mice. Body burdens of shrews continued to exceed those of mice throughout the uptake period. The Cs/Co ratio in shrews was A.00 compared to 1.50 for mice. The higher ratio in shrews was thought to be correlated with the shorter length of the gastrointestinal tract compared to that of mice. Total length in shrews was 273 i_15 mm compared to A16 1.29 mm for mice (Dunaway, 1971). Excretion proceeded at a faster rate in shrews than in mice (Fig. 15), which may reflect a difference in size of the animals, or general differences in metabolic rates between these two species. Thus, shrews did ingest pine seeds, even when offered sufficient volumes of alternative foods in the laboratory. Although these shrews were fed limited quantities of mouse meat, 78 .nmnm was main 8.3.09 Son.“ .0me $32,389.06.“ .0 H78 was mm up 300m mdponpm 35m OH msflpmmmfi” haddoanonno mods 030856.33 can mkmhnm 003.601.2031.“ 5.” 2633000 Repmaoonoa Rooms musmnH Mo 003590.“ was 83035000 502 333 m2: 2. cs 0n 8 o. 0.. on ON 0. mmosmu pmmnv 000 mflnp ca wcflpmms mums awhsm 0 0:0 .quoh 039 Mm: .mmdos mawsmw < .mofla umpoomumpflgz was mampnm cmfiflwplppogm mmwspmp aofl>wswp oapmfinomwpcmzoc m0 mamawxm a. .L. \ .‘ .wa madmfim 82 These findings, combined with the strong evidence of the similarity of Cs/Co ratios in mice and shrews, were sufficient to confirm that the seed-mouse—shrew food chain was not important on the field plot. The last route of radioisotOpic entry examined was through a feces-insect—shrew food chain. While no specific entomological studies were conducted, 73 miscellaneous arthropods found in feeders during each weekly inspection were collected, sacrificed, and measured for radioactivity (Table ll). No insect, except for a single katydid, 137 acquired more than 1,200 dpm of Cs; average radioactivity was 285 lBTCS and 2,075 dpm of 60Co per insect. The Cs/Co ratio in all dpm of . . . . 6O insects was low, only once exceeding 1.0. The high proportion of Co indicated that the insects' food source was either tagged seeds and/or fecal remains. Carabid beetles have been reported as consumers of Douglas-fir seeds (Dick and Johnson, 1958). Feeder examinations revealed few fecal remains in them during either summer of study; whereas remains were commonly found in winter. This was indirect evidence for removal of feces by some organism or organisms active during warm weather. Occasionally, ants (Camponotus pennsylvanicus) were Observed in the act of removing mouse feces. It seemed that shrew feces were removed less often, but this cannot be supported with evidence. It was informative to compare the field radioactivity of shrews with the periods when insects were active. Shrews maintained high body burdens of radioisotopes during winter when insects would prdbably be least available to them. When insects did become available the following spring, the radioactivity levels in shrews decreased 83 cNo S. E. available. Table 11. Body burdens of 137Cs and 0Co in arthropods collected from feeders on the live-trap and snap-trap field plots. Order Family N Radioactivity (dpm i_l S. E.) Cs/Co 13705 6000 Ratio Diplopodaa b 13 175 :_ 28 1,031 :_ 18h 0.17 Araneae b 3 56 22 386 155 0.15 Lepidoptera b 7 213 163 1,137 878 0.19 Orthoptera Tettigoniidae 8 1,281 1,127 10,612 9,63h 0.12 (katydids) Gryllidae 20 212 M1 1,396 257 0.15 (Nemobius) Acrididae 3 9O h9 299 185 0.30 Blattidae 1 669 ---° 8,320 --— 0.08 Hymenoptera Formicidae 8 8h 18 fill 107 0.20 Hemiptera b 2 h 1 83 27 0.05 Coleoptera b 5 32 15 21h 50 0.15 Diptera b 3 9 h 9h 18 0.10 Total: 73 277 125 2,0h6 1,068 0.1h aSubclass. bFamilies combined. 8h rather than increased as would be expected if this food chain were the primary source of radioactivity for shrews. The potential sources of radioactivity for shrews required consideration with the populational data presented earlier. Although the extent of food available from insect and mouse predation sources was unknown, the amount of pine seeds available as a food source was increased on both the live—trap and snap-trap plots by 25.2 kg. The live—trap and snap-trap plots maintained a high shrew population, whereas the control plot population seemingly disappeared. This direct and indirect evidence was sufficient to confirm that shrews on the tagged field plots were ingesting a considerable quantity of seeds. Thus, in both the laboratory and field, it appeared that the short—tailed shrew was an "opportunist" in its eating habits, and consumed white pine seeds when available. Body burdens of shrews in both the laboratory and.field were generally greater than those of 137Cs for shrews in the field mice in the laboratory. Body burdens of increased up to th dpm X 103/g in October, 1969, and decreased thereafter to approximately 70 dpm X 103/g for the remainder of the year. 3. Body Burdens in_Miscellaneous Vertebrates Eastern chipmunks were the only other species with sufficient captures to follow radionuclide levels throughout the study (Table 12). 137 Cs in these mammals never attained the levels of 137 Body burdens of the two primary species on the plot; in fact, Cs dpm/g never 85 .0H00H00>0 .0 .0 oz . Q .mqlm 00009 :0 hammmm 0080: 0000000.0 nu- 000.0 nu- 000.0 nu- 00.0 H 0000000000 0000 000 00\0 00000000 uu- 0H0.0 In- 000.0 nu- 00.0H H 0:00Ha0aa 0:0000H000 000 00\0 In- 0000.0 us- 000.0 sun 0.000 H 000H0000 000000000 000 0H\0 00H0000m In- 0000.0 uu- 0000.0 nu- 0.000 H 00000000000000 00>000 000 0H\0 nu- 000.0 nu: 000.0 nu: 00.0 H 0000000>000H 0H0 00\0 nu: 0H0.0 -1- 000.0 nu: 00.0 H 05000000000 000 HH\0 00>< In- 0H.0 In: H0.0 nun 00.0 H 000 0H\0 00.0 00.0 00.H 00.H 0H.0 00.0 0 00000000000H x0000. 0H0 00\0 00.0 0H.0H 00.0 00.0 00.0 00.H0 0 000 0\0 In- 00.0 -u- 00.0H In- 00.00 H H00 00\0 00.0 00.0H 00.0 0H.HH 00.0 00.00 0 000 0H\0 In- 00.0H uuu 00.0H I.. 00.00 H 0:0000awm.05000002 0H0 00\0 00.0 00.0 00.0 00.0 00.0 0.00 0 000 0\0 00.0 00.0 H0.0 00.0 00.0H 0.00H 0 000 0\0 00.0 00.0 0H.0 00.0 00.0 0.00H 0 000 0H\0 nu- 00.0 In- 0H.0 In- 0.0HH H 000 00\0 nu- 00.0 nu- HH.0 nun 0.00H H 0H0 00\0\0 In: 000.0 In- 000.0 nu- 0.00H H 00H 00\HH In- 000.0 nu: 0H0.0 nu- 0.00 H H0 00\0 In- [.000.0 -I- 1.000.0 nun .u 0.00 H 0H 0H\0 nu- + 000.0 .II + 000.0 00-: + 0.HOH H 000000000 000000 0 00\00\0 .m Hfiwafidz 0000 0000H “.0 .0 H.“ 0V 00000 0.0 .0 H.H 0\00H x 0000 000>00000000m 000003 0000 2 0000000 00 .0.00 0000 .mpoam 00000 mwhplmdcm 000 manplm>fia 03p so Umhdpmmo mmpwhpmphm> mdowqwafimomwa :0 00 was 00 mo 0200959 hwom .mH maan ow hma 86 exceeded 8% of the mouse levels throughout the study. The Cs/Co ratio fluctuated between 0.0h and 3.0; however, most chipmunks were less than 1.0, indicating a radioactivity source other than seeds. The low levels of radioactivity probably reflected the gradually increasing contamination of the field plot through June, 1970. Possible routes of entry for chipmunks with ratios greater than 1.0 were by secondary consumption of radioactive materials (probably insects), location of seeds occasionally dropped outside feeders by other consumers, or actual raiding of feeders. The last three sampling periods in late summer, 1970, included an individual chipmunk which, based upon the 05/00 ratio, apparently was successful in obtaining seeds from feeders or caches. When this one chipmunk was removed from consideration, 137CS did not exceed 2,000 dpm/g, or approximately the mean values for h% of the body burdens of mice. Several other vertebrate Species were captured at various times throughout the year (Table 12). The only other mammal with significant uptake of radioisotopes was the pine vole, which was small enough to enter the feeders freely. Voles were not commonly trapped in any of the plots except for one period of invasion of the snap-trap plot when a nearby right-ofiway for a power line was cleared. Equilibrium levels in pine voles appeared to be similar to levels in mice and shrews. None of the remaining species trapped on the plots contained body burdens suggestive of seed consumption (Table 12). Three southeastern shrews (Sorex longirostris) were snap-trapped, and two contained some 137 radioactivity. But all contained less Cs than 6000, which would not be expected in animals which were primary consumers of tagged pine 87 seeds. The suSpected entry route was through insects which this genera commonly prey upon (Buckner, 196A). Several species of birds were captured, and none contained more than background levels of radioactivity. Although pine mice and some chipmunks did consume pine seeds, there was insufficient information to determine seed consumption rates or seasonal patterns. None of the remaining vertebrates which were trapped contained radioactivity levels indicative of seed consumption. D. Bases for Determining_Seed Consumption i t e Field 1. Correlation Technique Between the Laboratory_and Field Data It appears necessary to summarize what is already known, and what must be done in order to derive estimates of seed consumption from the field data. The laboratory data are the bases for the following conclusions: 1. ingestion rates may be determined from the equilibrium body 137 burden of Cs in mice, 2. the Cs/Co ratio can be used to predict the day of excretion, 3. excretion rate of 13703 varies minimally with temperature and feeding rate, and maximally with the mode of entry into the mouse. The field data give the following: 137 1. measured body burdens of Cs and 60Co in mice which were not at equilibrium, 2. none of the field data would allow a prediction of seed ingestion rates without correlation to laboratory data. 88 In order to determine seed consumption rates in the field, a cor- 137Cs and the laboratory regres- relation between field body burdens of sion of equilibrium to seed ingestion rates was essential. Direct laboratory-to-field extrapolations have not proven valid for mammals. An alternative method was to derive a correlation between animal metabolism and the rate of elimination of a radioisotopic body burden. The question of whether elimination of injected radioisotopes can be correlated to metabolism has been examined with inconclusive results (Baker and Dunaway, 1969; Baker, 1970; Wagner, 1970). The 18 only method which gave reliable results was the D2 0 method used by MUllen (1971). Differences in elimination of 137 Cs were signi- ficantly correlated to various metabolic parameters in both injection and chronic-feeding studies, as mentioned earlier. Differences due to the mode of ingestion were also emphasized earlier. In contrast to these differences was a comparison between the laboratory and field excretion rates derived during this investigation (Fig. 17). These data were not plotted in terms of percent retention, but in terms of concentrations per gram of liveabody weight. Thus intercepts differed, due to unequal or unknown feeding rates, whereas the slopes did not differ, regardless of the intercept, particularly 137 during the first 20 days of excretion. This indicated that Cs was not responding to the expected changes in metabolism between the laboratory and field, and a direct correlation could be used to correct the field body burden to the equilibrium body burden. Whole4body retention for 8 mice captured alive from the snap-trap plot was followed in the laboratory to compare with retention by animals '37Cs WHOLE-BODY RADIOACTIVITY (dpm/q) Figure 17. 89 LABORATORY (21.1°C) --o-- 50 seeds/day —A— 100 seeds/day —'0— UNKNOWN seeds/day (FROM SNAP- TRAP AREA) FIELD (UNKNOWN °C) --A-- UNKNOWN seeds/day (0N LIVE- TRAP AREA) 10 20 30 4O 50 60 7O 80 90 TIME (dayS) Mean retention of 13703 in Peromysgus leucopus from the laboratory and field. Data from Tables B—2h, B-35. and B-36. 100 90 remaining on the radioactive live-trap field plot. If mice remaining in the field had greater wholeébody retention than that of the laboratory-maintained animals from the snap-trap plot, it would have suggested a delay in initiation of excretion due to consumption of tagged pine seeds from caches available on the plot. The similar ex- 137CS cretion rates for both laboratory and field indicated that both and 60Co were excreted immediately upon termination of feeding tagged seeds in the live-trap plot. Thus it seemed that mice had not cached pine seeds on the plot, or had consumed such caches prior to termination of feeding on September 1, 1970. Another explanation of the similarity between the laboratory and field data was possible. Suppose that the rate of excretion was greater in the field due to an increased metabolism and greater activity. Then the equality between excretion rates would indicate a slightly greater ingestion of contaminated food in the field compared to the laboratory. This was possible in the field, as seeds taken from feeders were not relocated and removed from the plot. Other food sources ingested by the white-footed mouse could have radioactive levels which would maintain the field retention of the mice at a level higher than ex- pected. If such were the case, however, it was highly unlikely that retention would have been similar throughout the 100 days of excretion that were followed in both the laboratory and field. These results indicated that for chronically-fed mice, excretion 137 rates of Cs were not severely influenced by confinement in the laboratory or by temperature differences. The comparison of radio- isotopic tissue distribution, discussed earlier, also suppported this 91 parallelism between the laboratory and field. These similarities allowed a direct correlation to be made for the excretion rates of 137Cs between the laboratory and field. Excretion rates after in- Jection, single-feeding, or chronic ingestion of tagged water would not be as reliable as excretion after chronic feeding for this correlation. 2. Conversion of Field Data to Estimated Seed Consumption Rates ——-—————-—-———— ig_White-footed Mice 137Cs dpm/g body Seed consumption rates were calculated from the burdens, since the 60Co dpm/g data were too variable to be used ex- clusively in determining seed consumption. The field data were cor- rected through use of three empirical calculations between the labora— tory and field data. These calculations were to: 1) determine the day of excretion in the field, 2) estimate the equilibrium body burden in the field, and 3) correlate the field equilibrium with the laboratory equilibrium. The first calculation was to determine day of excretion for the field animals. It was obvious that mice trapped on the live-trap plot were not at day 0 of excretion (Table B-25 and B-9), thus measured equilibrium values (Table B-lT) were actually lower than true field equilibrium by approximately one day of excretion, based upon the Cs/Co ratios. A regression was established between the Cs/Co ratio and the first three days of excretion in the laboratory (Table B-9), which was then solved for time: t = (Y - 2.h07) / 1.6227, 92 where Y = Cs/Co ratio measured in the field animal, and t = day of excretion, with a constraint that (t) was valid only between day 0 and day 3. Any predicted day greater than 3.0 was arbitrarily assigned day 3.0, as this was when the maximum Cs/Co ratio occurred in the laboratory. The r2 of this regression was 0.992. Once the day of excretion was determined, the second calculation was employed using the familiar three-component equation to convert the body burden on the day it was measured to the estimated radio- activity (or equilibrium body burden) on day 0. The retention equation was derived from percent retention data averaged for all laboratory animals (Table 2): -l.091t -O.l98t -0.0332t) A = At / (0.1h00 e 0 + 0.0382 e + 0.8213 e where A0 = equilibrium body burden at time 0, At = radioactivity measured in the field at time t, and t = day of excretion as determined by the Cs/Co ratio. Once this had been determined, the laboratory equilibrium had to be correlated to the field equilibrium by the third calculation. Minimal differences were observed between the laboratory and field excretion rates, particularly during the first 20 days. The nonmetabolic 137 behavior of Cs in these mice formed the basis for using a direct correlation to estimate consumption rates in the field. The regression equation determined for mice maintained under laboratory conditions was applied to estimate the grams of seed consumed per day: 93 10 (A0) = 5.15279 + 0.216386(sex) + 0.01672h(temp) + 1.03h891(1n seed) - 0.00267h(sex x temp) + 0.000096(temp x ln seed) + 0.000SS9(sex X temp X ln seed), where 1n (A ) = natural logarithm of the equilibrium.body burden as 0 determined in the previous equation, sex = 1.0 for males and 2.0 for females, temp = temperature in F, and ln seed = natural logarithm of the total seed weight (g) eaten during the last A2 days in the labora- tory. This equation was solved for the weight of seed eaten, by a process of iterative solutions until the estimate of (1n seed) changed less than 0.0002 g. The derived seed weight was divided by A2, as the values used in the derivation of the equation were the sum of M2 days of ingesting seeds. The average seed weight was 18.25 mg and was used to convert weight to an estimated number of seeds eaten per day. E. Estimated Seed Consumption by_Small Forest Mammals l. White-footed Mice Ingestion rates ranged from h to 390 seeds per day within the same mouse from the field plot (Table B-26). Mean seed ingestion throughout the year was 87 :_8 seeds per day for 101 captures on the live-trap plot. The ingestion rates were only slightly modified, by the effects of temperature, sex, and feeding rate, from the pattern indicated for the body burden of 137Cs (Fig. 13). Thus the mice consumed more pine seeds in summer and autumn than in winter or spring. Predicted values of seed consumption rates are realistic except 9h for those animals at very high ingestion rates. The ad_libitum in- gestion rate in the laboratory was predicted as 19h seeds per day (see Fig. 7 and discussion). If the literature estimates of ap- proximately 50% increased energy expenditure in the field are realistic, then estimates up to approximately 290 seeds per day may be valid for the field data. When the raw data for mice predicted to be ingesting more than 137 290 seeds per day was examined, the Cs body burdens did not appear to be abnormally high. For example, the maximum body burden was found in a dominant male mouse who was trapped on the field plot over a period of 377 days. This body burden was l8h,h00 dpm/g r 137 fo Cs, which would correlate directly to about 200—250 seeds 137 per day without a correction for the Cs/Co ratio. Whereas the Cs levels were within reason, the 6000 values appeared to be extremely low. The reason for this was not clear. Tissue analyses of animals from both the laboratory and field indicated that about 1/3 of the wholeébody 6000 was contained in the cecum contents. Perhaps cecal blockage occurred in these low 6000 animals, but there was no in- dication of such happening in any tissue-sampled animal. More likely, these mice had high ingestion rates of food and passed the 6000 out of their gastrointestinal tracts much more rapidly than did the average animal. An ag_libitum study of pine seed consumption in the laboratory would have been of value for these mice. 95 2. Short-tailed Shrews The importance of the short-tailed shrew as a seed consumer was unsuspected and greatly underestimated before the study began, and equilibrium response in the laboratory was not investigated as thoroughly for this species as for white-footed mice. Shrews acquired 137 approximately twice as much Cs dpm/g and 90% as much 6OCo dpm/g at equilibrium as did mice at the same ingestion rate (Fig. 15). 137 Differences for Cs may be due to ingestion of a greater proportion of the seed coat while shelling seeds, whereas the lower 6OCo body burden may be due to the shorter gastrointestinal tract and/or lack of a cecum in shrews. Therefore, an overestimate of seed con- sumption by shrews would be derived by employing the same computational procedures as were applied for mice. Shrews are purported to be highly active metabolically, but when 137 137 elimination rates of Cs were compared with those of mice, Cs was lost at only a slightly faster rate (Fig. B—5). As with mice, the 137 initial 15 days excretion of Cs was similar for shrews in the laboratory and field (Fig. 18). The similarity in excretion patterns between laboratory and field supported the seed consumption theory for shrews, and also indicated a noncaching behavior. The characteristic Cs/Co relationship differed between mice and shrews, with shrews usually having the higher ratios (Table B—25). The peak Cs/Co ratio occurred on day l of excretion in the laboratory (Table B-22), and.en arbitrary assumption of day l was employed for all shrew calculations. This would serve to underestimate seed 96 105 O LABORATORY: UNKNOWN seeds/day 2 A FIELD: UNKNOWN seeds/day o LABORATORY: IO seeds/day . 104 103 mos WHOLE-BODY RADIOACTIVITY (dpm/g) 102 O 10 20 3O 4O 50 60 TIME (days) Figure 18. Mean retention of 137C8 in Blarina brevicauda_ from the laboratory and field. Data from Table B-27. 97 consumption by shrews in the field, since a majority of shrews had passed the peak Cs/Co ratio (Table B-2l). These assumptions were used to determine seed consumption rates for short-tailed shrews on the live-trap field plot (Table B-28), using the same seed consumption equation as used for mice. Seed consumption varied from 1 to 770 seeds per day with a mean of 158 :_10 seeds per day for 1&9 captures on the live-trap field plot. These estimates appeared to be realistic except for highest rates of ingestion. This same problem was Observed in mice. The seasonal pattern of ingestion was not altered from that for the body burdens (Fig. 13), with high ingestion rates from late summer through winter and lower rates in spring and summer. The results confirmed a greater rate of seed consumption by shrews than for mice. 3. Seasonal Aspects 2£_Seed Consumption py_Small Forest Mammals Employing estimates of seed consumption for these two species, a yearly average of 1.60 g of pine seeds was consumed per mouse- day by white-footed mice, and 3.00 g per shrew-day by short-tailed shrews on the live-trap plot (Table 13). Estimated seasonal rates of food consumption per mouse ranged from 0.38 g/day in winter to 2.26 g/day in summer. The shrews were similarly estimated to be consuming from 2.10 g/day in summer to h.l3 g/day in autumn. The "calendar of captures" method of Petrusewicz and Andrzejewski (1962) was used to determine residence time on the plot for each individual. The method assumed continual residence on the plot between the first and last captures, even if the animal 98 .000\Hwox oa.w n 0.0 x 000\m 650900000 mmo.a n :Om.o x 0w.a "00Q80x0 Mom .Awmoav SpHEm 805% Aw\000 000.0V 00500> 0050000 0H000pcoa 05cwm €059 00>0H00 mmpwewpmmO .005000>059.4M 000 05moo500 4M.op 0095905pp0 pcmoaom Q .Ommfi .mm smnEmemm op @000 .:m 0050 505% 0000559 0009 55059000500 055000 op 00>0w doflhmmm A000\Hwoxv 000 00.0H 00.0 00.0 00.0H 0H.0H 00.0H .5.0 o 000 soap00000 00.0 00.0 00.0 00.H 00.0 0H.0 .H.a oagoH0o 00000>¢ 0000\00 00.0 0H.0 H0.0 00.0 0H.0 00.0 .0.0 sofipass0aoo 00.H 00.0 00.H 00.0 00.H 00.H .H.0 0000 000s0>< 0.H0 0.00 0.00 0.00 0.0HH 0.HOH H00oe 000V 000H000sssooo< 000.0H 000.0 000.0 000.0 000.0 00H.0 H00oe 000.0H H00 000.H 000.0 000.0 H00.H .0.0 000 soapass0soo 000.0 000.H 000 00H 000 H00 .H.0 0000 0000sH000 000.0 H00 o00.H 0H0.H 000.H 000 H00oe 0H0.0 000 000 00H.H 000 000 .0.0 poHa 0H000 000.0 000 000 H00 000 0H0 .H.0 so 0000 000000000 va msmcmmm 0H0.0H 00o.0 000.0 H00.0 000.0 00H.0 H00o0 sopm 00sa0pso 0000 haywmw smEE5m mnflsmm 509003 285p5< 000059: 500% 05p 00 commmm ho uoflpmm mmflommm EmpH .poam 00009 wnlm 0 so 00009005Qom 005000>0an mafiawam 0:0 05m0050H 05owNEopmm 09 00000 0590090 05:0m mo cowpm85mcoo 005000 000 00200000 wo 00pmaflp0m .MH 00009 99 was not captured. Half the time between trapping periods before the first capture and after the last capture was added to the residence time. On a yearly basis, the mouse population spent 2,008 days on the live-trap plot, whereas the shrew population spent h,Ol2 days (Table 13). Mean seasonal consumption of seeds for each species was then multiplied by the seasonal residence time for that species to estimate total seed consumption and ingestion rates for each season. For the year, the mouse population consumed 3.2 kg of seeds, whereas the shrew population consumed 12.0 kg of seeds, for a total con- sumption by both species of 15.2 kg. An independent check of this consumption was derived from the feeder utilization data (Table B-lS). A total of 18.7 kg of seeds was removed from or consumed within the feeders (Table 13). These two species of mammals accounted for 81.h% of the quantity of seeds utilized. This estimate would be closer to 100% if other consumers had been followed more closely. Such potential consumers were transient small mammals, sciurids on the area, birds, and granivorous insects. Seed accountability was lowest during spring and summer and indicated that the problems may either have been due to seasonally active species, such as eastern chipmunks and insects, or caching of seeds. Caloric measurements were not made for the pine seeds used in this study, but a close estimate can be made using 7,h08 cal/g of endosperm in Pinus monticola, a closely-related species (Smith, 1968). Based upon this conversion factor, the yearly average con- sumption of pine seeds by mice was 7.0 kcal/day. McNab (1963) 100 estimated the daily food requirement of Peromyscus maniculatus as 1h.0 kcal/day. Drozdz (1967) reported consumption rates of 12.1 to 13.2 kcal/day for 22-g Clethrionomys glareolus and 12.1 to 17.0 kcal/day for the 29-g Apodemus flavicollis in beech forests of Poland. Pearson (1960) estimated a consumption rate for a 9-g Reithrodontomys megalotis at 8.6 kcal/day in December and 6.6 kcal/day in June. The expected daily consumption rate for white-footed mice should be in the range of l2—1h kcal/day. The ag_1ibitum ingestion rate predicted for mice in the laboratory was 19h seeds/day, which may be converted to an estimate of 15.6 kcal/day for the white-footed mouse. Thus, this single food source of white pine seeds provided approximately h5-50% of the daily food requirement of mice. Shrews apparently were consuming seeds almost exclusively, as their yearly average consumption rate of pine seeds was 13.2 kcal/day. This Ican be compared to laboratory-determined values of 12.7 kcal/day derived by Pearson (19h7), or 9.7 i_0.9 kcal/day reported by Buckner (196%). It appeared that this equilibrium technique provided reasonable estimates of the fate of eastern white pine seeds, and of the con- sumers of these seeds. Mice consumed 17% of the seeds, whereas shrews accounted for 6h%, or approximately 3.8 times more consumption than the mouse. The remaining 19% was unaccounted for but could have been lost in caches or consumed by other species of vertebrates and insects which were active during the summer. V. DISCUSSION A. Estimation 2: Seed Consumption Many parameters affecting seed consumption of free-ranging mammals are difficult to define. Factors such as behavior, daily activity, time of feeding, and climate could influence movement of 137Cs and 6000 through free-ranging mice. The nature of these factors require a synthesis of information from the disciplines of mammalogy, health physics, and radioecology. The goal of this synthesis was an ecological statement concerning seed consumption as determined by radioisotopic techniques. Most mammalogists and ecologists would contend that results for a confined laboratory animal can not be directly correlated with data for a free-ranging wild animal of the same species, and that "...we must extrapolate from laboratory to field conditions" (Golley, 1968). Most studies assume a factor of approximately l.h to 2.0 in correlating the laboratory to the field, whether the variable is food ingestion, respiration, or energy flow (Pearson, 1960; Odum gt_gl,, 1962; Johnson and Maxell, 1966). Darnell (1968) suggested that we simply use the best estimates available for the correlation. Ryszkowski and Petrusewicz (1967) estimated the error at less than 100% if no cor- rection was made, but measured a 320% difference based upon maximum and minimum respiration rates in bank voles (Clethrionomys glareolus). Their conservative estimate was based upon the premise that all 101 102 factors would not be operating to either increase or decrease metabo- lism at the same time, and that each variable acted independently of other variables operating at the same time. Radioecologists and health physicists would contend that excretion of a radioisotope is dependent upon many variables which have been shown to be significant in laboratory studies. These variables include tem- perature, body weight, age, species, and X-irradiation. Sex has not 137 generally been recognized as a variable except for Cs in humans (Hanson gt al., 196M; Scott, l96h). A few radioecological studies have described significant dif- ferences between laboratory and field excretion rates for mammals handled identically (Orr, 1967; Dunaway and Story, in prep.). Such studies generally have been injection studies. The almost universal conclusion of isotope-oriented studies is that there are, or should be, differences between laboratory and field excretion rates. Thus, most mammalogists, ecologists, and health physicists would agree that such laboratory versus field differences are to be expected and perhaps reflect real processes in organisms. For these reasons, the findings of identical excretion rates of 137Cs between mice in the laboratory and field was completely unexpected. In fact, the field study was undertaken with the hope that a correlation 137 could be made between Cs excretion rates and metabolism based upon another study conducted at the same laboratory (Baker 33 gl,, 1970). Such a correlation was not proven for the long-term retention component 137 for free-ranging animals with Cs. Other investigators have ex- perienced difficulties in attempting to establish correlations between 103 137 excretion rates of radioisotopes and metabolism. For example, Cs was purported to be an analog of potassium in mammalian organisms (Davis, 1963). with similar metabolic behavior and location in cells, but has not been readily correlated with oxygen consumption (Baker, 1970). Various laboratory studies with mammals have shown temperature 137 to be an important variable with faster excretion of Cs at lower temperatures, i.e., higher metabolism. Thus some information suggests 137 a metabolic behavior of Cs, where other data have been unable to confirm any correlation between excretion and metabolism. 137 Two results for Cs in this study need to be emphasized. First and most important was the nonsignificant differences in excretion after chronic feeding, no matter what the temperature within the range examined, or whether the animal was maintained in the laboratory or captured from the field. Secondly was the almost uniform distribution 137 of Cs in all tissues of animals that were at equilibrium with their 137Cs, Obtained from radioactive food source. Thus it appeared that a normal food base, moved freely throughout the organism and did not overtly respond to environmental stimuli such as temperature or feeding rate. 137 This conclusion suggested that Cs was an ideal element to use in determining food consumption rates in free-ranging mammals. Equi- 137 librium levels and excretion rates of Cs in mice did not appear to be influenced by metabolic parameters which severely influence the interpretation of such radioisotopic techniques. This equilibrium technique was applied with laboratory and field pOpulations of white-footed mice and short-tailed shrews. The labora- 10h tory study established a highly significant correlation between equi- 137 librium of Cs and its ingestion rate in mice. Extrapolation of the field data resulted in an estimated yearly consumption of 7 kcal/day for mice, or approximately 50% of the ex- pected daily consumption of all foods. Maximum consumption occurred in summer Just prior to the availability of the new mast crop, and decreased to a minimum during winter. Classically, late winter through early spring is thought of as the period of greatest food stress, with overwintering populations dependent upon the amount of available food. The decline in seed consumption rates suggested that mice were not food-limited during the winter period, but that their food habits changed when the mast crop became available. The prevalence of chewed hickory nuts in nest boxes indicated that this food formed a sub- stantial portion of the winter diets in mice. Nonstorage of the readily-available pine seeds, even allowing for a change in food habits, led to a consideration of winter activity, especially food gathering during winter months. The impression Obtained from all evidence was that mice severely reduced all unnecessary activity, and remained in the nest most of the time. Mice perhaps were living off their body reserves, occasionally supplementing their reserves with a hickory nut or acorn. It appeared that the home range was smaller during winter, also an energy-conserving mechanism. This lack of winter activity has also been suggested by Gebczynski (1966). The shrew population was responsible for consuming approximately four times as many seeds as were white-footed mice. That shrews might be more important than mice as seed consumers has not been 105 reported previously. In fact, Campbell (1970) reported that the short—tailed shrew did not damage longleaf pine seeds sufficiently to prevent germination in a laboratory study, in direct contrast to results of this study using the smaller and softer-shelled white pine seed as food. It is of interest that Williams (1936) considered the short- tailed shrew as the most influential mammal, in terms of abundance, activity, and food consumption, in beech-maple forests of Ohio. It appears that this small but numerous mammal is of major importance as a food consumer throughout the Eastern Deciduous Forest. Future studies of seed loss or forest regeneration problems should include this species as an important member of the consumer community. The problems of handling this species in the laboratory and field were numerous, and an explanation of some techniques developed in this work might aid future studies. Shrew mortality is typically high in live-trapping studies. Graber (1969) examined seed loss to rodents in Maine, and observed an 88% mortality and no recaptures of his shrew population (Blarina'brevicauda and Sorex cinereus) by live-trapping. Campbell (1970) trapped 10h shrews (B, brevicauda and Cryptotis parva) in 18,000 trap nights but experienced a 62% trap mortality and an additional 11% mortality "...before they could be Observed in the laboratory." Kangur (195h) also ex- perienced mortality problems with three species of Sorgx_in Oregon, as only 5 animals out of 29 lived as long as four days in captivity, with h0% being found dead in the traps. Rood (1958) trapped 2O short-tailed shrews in a Michigan study, but had 35% die in the 106 traps even though he checked them at h-hr intervals. Differences in mortality between this study and those in the literature cannot be definitive as to cause, but a partial explanation can be offered. Traps were entirely dry, since sunflower seeds were used as bait, as practiced by Blair (l9h0), and cotton batting pro- vided a retreat away from the metallic trap. Shrews are hyperactive, especially when trapped, and I felt that the hygroscopic oatmeal- peanut butter bait often used in other studies fouled the shrews' fur in their attempts to escape from the trap, thereby reducing the insulative qualities of their fur. The practice of setting traps late in the day, running them early, and providing shrews with mouse meat probably contributed to the high survival Obtained. Then, during counting or weighing procedures in the laboratory, every shrew was given water until refusal. I believe that live-trapped short- tailed shrews die more from a loss of insulation and water deprivation than from food starvation. Shrew mortality in the live-trap plot was approximately 27% that of the control plot even though approximately five times more shrews were captured on the live-trap plot. These differences perhaps can be attributed to two factors. The second day of each trapping period on the control was also the first day of trapping on the live-trap plot. With twice as many traps set on this day, the control was the first plot set and the second plot run the following morning. This factor probably contributed to a higher mortality of the control shrews, as they were confined for a longer average time in the trap before being checked. 107 The second factor was part of the study design, and appeared to be an influence of using sunflower seeds as bait. The live-trap plot had white pine seeds distributed over the 2—ha plot each week, whereas the control received no additional food. Sunflower seeds served as trap bait in both plots and was provided in approximately equivalent amounts. Either shrews on the control did not recognize sunflower seeds as food, or shrews on the pine—seed-laden live-trap plot more readily accepted sunflower seeds as food. The snap-trap plot also maintained a high shrew population all year, based upon fecal remains found in feeders. Since a variety of seeds normally form a portion of the shrew diets (Hamilton, 1930; Moore, 19h2), they should have recognized sunflower seeds as food. B. Impact 23 Small Mammals 2n_Forest Regeneration Artificial regeneration of forest lands has a history of repeated failures. Environmental factors are extremely important in seed survival, but loss of seed to rodent consumers seems to have re- ceived much emphasis. Recent studies have examined the effective- ness of various measures to protect seeds against rodents (Lawrence and Rediske, 1962; Graber, 1969), time of sowing (Radvanyi, 1970, 1971), and consumption rates (Abbott, 1961; Abbott and.Quink, 1970). The importance of small mammals as seed consumers can be compared in the following table: 108 Seed Species Loss to Mammals Reference Picea alba 28% Radvanyi, 1970 Pseudotsuga menziesii lh% Lawrence and Rediske, 1962 28% Gashwiler, 1971 h1% Gashwiler, 1970 Pinus contorta 19% Radvanyi, 1971 Pinus strobus 100% Abbott, 1961 61% Graber, 1969 8h% Abbott and Quink, 1970 8h% This study Species with low losses to mammals generally have an increased loss to other factors. Survival of 10% of the seed through the first year would be considered satisfactory. This study examined the potential consumption of pine seeds by natural mouse and shrew populations in a mature oakéhickory forest. A total of 25.2 kg of seed was placed on each of two plots over a 58-week period. Of this amount, an average of 21.2 kg (89%) was removed by the animal populations. Shrews and mice consumed 15.2 kg (81%) of the seeds removed on the live-trap plot, and this consumption was estimated to be 50% of the daily food requirement for mice and approximately 90% for the shrews. An estimated lO—ll kg/ha of seeds would be consumed annually by these two species. Estimates of yearly tree seed production in pure stand of pines range from 10-15 kg/ha (Turcek, 1967; Abbott and Quink, 1970). Hard— wood forests generally produce greater amounts of seed; estimates from Polish forests range from hh to 55 kg/ha (Gorecki and Gebczynska, 1962; Drozdz, 1966). It appeared that there was more than sufficient 109 food available for the mammal population on the live-trap plot. In a natural situation, the influence of other consumers (e.g., deer, sciurids, and insects) would reduce the seed supply for rodents, but could not be quantified in this study. An intrinsic pattern of consumption of pine seeds may be outlined from this study, with the lowest rate of consumption occurring in late autumn through winter, and the highest rates occurring in summer and early autumn. Radvanyi (1970, 1971) reported a low rate of seed destruction during the winter months, and I concur with his recom— mendation that direct seeding, in similar forest ecosystems, should be attempted only in the winter months, in order to avoid the greatest loss to small mammals. A goal of this study was to determine if the disappearance of white pine from mixed hardwood-pine stands might in part be due to the seed-consumption habits of small forest mammals. Based upon one year of field data, mice appeared to prefer white pine seeds during the summer months only. Pine seeds were essentially ignored by mice during winter after the mast crop became available. The shrew popu- lation appeared to increase their consumption of pine seeds during the periods when mice were consuming other foods. Shrews are probably unable to consume the large and thick-shelled hickory nuts and acorns, and presumably were more dependent upon the smaller seeds and insects available on the forest floor. Tunneling of shrews into new areas was restricted during winter, and probably only those seeds landing near tunnels would be discovered by shrews. The ease with which mice and shrews could locate feeders probably overestimated potential seed 110 consumption, in comparison to the dissemination of seeds under natural forest conditions. The importance of the short-tailed shrew in this respect is difficult to evaluate, but potentially, shrews may be more important than mice as consumers of pine seeds, par- ticularly after the hardwood mast crop becomes available. Sufficient seeds should escape detection by shrew and mouse populations however, and the loss of white pine from mixed forests such as these probably is not caused through seed consumption. 37 C. Effect 2£_Mode 2£_Entry Upon l Cs gptake and Retention Parameters 137Cs led to a con- The nonmetabolic behavior of chronically-fed sideration of the metabolically-correlated results observed in other studies. Differences between other studies and this study seemingly were associated with the mode of entry into the animal. Health physics studies usually have been conducted with injected animals to determine excretion parameters. These parameters are then integrated in an uptake equation to predict equilibrium and radiation dosages for that body burden. The reason for using excretion data to predict uptake char- acteristics has been an assumption that the movement of elements is governed by rate constants, whether the movement is incorporation into, or excretion from, the body pool under consideration. Robertson (1957) has criticized extrapolation from injection studies due to the invalid acceptance of assumptions basic to tracer studies. The logic of the practice of integrating data from excretion studies can be questioned due to the processes affecting the mode of entry. There appear to be two offsetting errors in this method, if excretion 111 after chronic feeding is used as the base of comparison. One concerns the "mirror image" comparison of the chronic uptake curve to the sub- sequent excretion curve observed in the same animal; the second compares excretion after injection to excretion after chronic feeding. The first is the "mirror image" comparison. After a period of chronic uptake, all excretion pathways are operating maximally, and excretion will be normal from day 0 on throughout the study. But during the first few days of chronic uptake, a significant change must occur in 137 excretion. The amount of Cs excreted will initially be nearly zero, reflecting only the loss of "background" radioisotopes Obtained through normal diets; but then must undergo an exponential increase up to the maximum which occurs at equilibrium with the ingestion rate. The gastrointestinal tract will act as a "sink" for the first few days, until the radioactivity is evenly distributed through the tract. Thus, 137 retention of Cs, during the first few days of uptake, should be greater than would be expected from use of excretion data. This con- tention was substantiated by the mirror image comparison between mean percent uptake and the inverse of mean percent retention (Fig. 9). If these differences can be observed using the same animal as its control in both uptake and excretion equations, then the widespread use of injection studies to determine excretion parameters can be questioned. And one of the basic assumptions of tracer methodology, that of identical behavior in both uptake and excretion, can be proven invalid. The second error in using excretion to predict chronic uptake was indicated by a comparison between chronic feeding and injection studies. 137 Injected animals excrete Cs faster than in chronically—fed animals 112 (Table A and Fig. 8). The error will be in the same direction as the error observed during chronic uptake and, upon integrating the ex- cretion equation, will create a closer correlation to chronic uptake than will the excretion rate seen after chronic feeding. It seems probable that the rate of isotope movement was involved in these differences. In the acute case of intraperitoneal injection, the entire quantity of isotope competes at the same time to cross a particular membrane (peritoneal or cellular). If the maximum rate of incorporation into tissues has been exceeded in injected animals, the excess would be sloughed off via other pathways. One potential pathway could be a reversal of the uptake from intestinal contents, with more isotope excreted in the fecal material than found in chronically-fed animals. Of the tissues which do incorporate the radioisotope, the short-component, rapidly-cycling tissues are the only body pools which incorporate much of the tag after injection. These short-component tissues will, of course, also excrete the isotope rapidly, resulting in faster excretion curves. Chronically—fed animals have a greater percentage of the total isotope incorporated into long-component body pools, compared to injected animals, and have a greater retention during the first few days of excretion. These theories were not examined during the study, and while admittedly hypothetical, perhaps explain some of the Observed differences. The correlation between the integrated curve derived from injection studies of excretion and the chronic uptake curve may be a coincidental relationship of these two offsetting errors, thereby allowing the close predictability reported by various investigators. 113 The importance of the errors in the present methodology become 137 apparent by reference to Cs excretion curves Observed after single feeding and chronic feeding (Fig. A-3 and A-S). Retention in 137 chronically-fed Cs animals was 2.8 times greater than for single feeding after 20 days of excretion. The importance of this elevated 137 long-term retention of Cs is in determining total radiation dosage. Excretion data from injection studies underestimates the total dose, based upon this reasoning. Whether the processes of food ingestion, digestion, and assimilation can be equated with injection or ingestion of radioisotopes in water, is a subject which needs more investigation. If such a difference does occur, as was found in this study, then radio- ecologists should consider its importance in radionuclide cycling, and health physicists may need to reconsider their estimates of dose rates to man from ingested food stuffs. VI. SUMMARY AND CONCLUSIONS Consumption rates of white pine (Pinus strobus) seeds by white- footed mice (Peromyscus leucgpus) and short-tailed shrews (Blarina brevicauda) were determined in the laboratory and field. Pine seeds 137 were uniformly tagged with Cs and 60Co and then fed chronically to the mammals at specific ingestion rates. An equilibrium technique was then used whereby seed consumption was predicted from the equi- librium body burdens of 137 Cs. Laboratory variables affecting equilibrium levels were the feeding rate, and to a lesser extent, sex and temperature. As ingestion rates were increased (2, 10, 50, 137 60 and 100 seeds per day), equilibrium body burdens of Cs and Co also increased proportionally. Similarly, as temperature was in— creased, between h.h and 21.1 C, the equilibrium body burden at each ingestion rate was also increased. For any temperature-ingestion rate combination, females acquired higher equilibria than males. This equilibrium technique was then applied to a mammal pOpulation in a mature second—growth oak-hickory forest of eastern Tennessee during July, 1969 to September, 1970. This area is characterized as a warm temperate rainy climate, and the soils are primarily Utisols. Principal mammalian species studied in this forest type were the white- footed mouse and short-tailed shrew. The 2-ha field plots were located along the crest of one ridge of this dissected valley floor at elevations of about 300 m. 11h 115 Tagged white pine seeds were dispersed in feeders at a rate of 222 g/ha per week for 58 weeks. Small mammals were live—trapped periodically to determine body burdens of radioisotopes and were then released at their point of capture. Field application of this technique was successful only because (137Cs) a dual-isotope tag was employed, using one isotope which accumulated in tissues, and the second (60Co) as a food tag with low assimilation. The ratio between the two isotopes during ex- cretion in the laboratory was used to determine day of excretion for the field animals. A direct correlation of seed consumption from laboratory to field was indicated, based upon identical excretion 137 rates of Cs in both the laboratory and field. The derived day of excretion, determined from the ratio between the two radioisotopes, was then incorporated in the excretion equation from the laboratory 137 to estimate equilibrium of Cs for mice in the field. The equi— librium level was then corrected for the influences of sex and temperature, and solved for the seed ingestion rate. Seed ingestion rates per mouse varied seasonally with a maximum consumption rate in summer of 2.3 g/day, and a minimum of 0.A g/day in winter. Average yearly consumption rate was 1.6 g/day or 7.0 kcal/day. This was estimated to be approximately h5-50% of the total food consumption for this species. Thus the equilibrium tech- nique provided realistic estimates for consumption of a single food source in a field situation with free-ranging populations of white- footed mice. The importance of the short-tailed shrew as a seed consumer has 116 been underestimated. Numerous studies have indicated that the shrew does consume seeds, but more interest has been shown in this as a curiosity of the species rather than in light of the destructive effect of such consumption. Seasonal seed consumption was maximum in autumn (A.1 g/day), and minimal in summer (2.1 g/day). Average yearly consumption of pine seeds was 3.0 g/day, or 13.2 kcal/day. Relative consumer importance was derived from two factors: the seed consumption rate per individual combined with the population level of each species. Shrews had consumption rates approximately 1.9 times greater than mice and maintained a population about twice as large as the mouse population. Thus, the shrew was reSponsible for approximately four times as much seed consumption as the white- footed mouse. A total of 25.2 kg of seed was placed in each plot, with 21.2 kg (8h%) removed or consumed in the feeders. Mice and shrews consumed 15.2 kg or 81% of those seeds which were utilized. The populations of both mice and shrews were estimated to be able to consume lO-ll kg/ha of seed annually. The disappearance of white pine from mixed forests, such as this oak-hickory type, does not appear to be at- tributable to consumption of pine seeds by the mouse and shrew populations. Another important finding relates to the radioecological and health physics aspects of chronic feeding. Apparently there is a difference between the excretion parameters for injected wild mammals and chronically-fed wild mammals. In general, the present methodology utilizes a determination of excretion parameters from injected animals 117 to establish the characteristics and equations for chronic uptake. This study indicated that: 1. 137 excretion curves of injected Cs do not adequately represent actual excretion curves after chronic feeding, 137 excretion of Cs after single-feeding was faster than after chronic feeding, 137Cs do not excretion curves after chronic feeding of adequately characterize the uptake curve as observed in the same animal, equations derived from excretion curves after injection of 137 Cs prObably predict chronic uptake more closely than actual excretion after chronic feeding due to a coincidental similarity of two separate processes, and estimates of radiation dosages derived from excretion studies after injection are probably lower than those derived from excretion studies after chronic feeding. Further applications of this method could be used to char- acterize total energy flow through a consumer. 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Schnell. 1967. Forb-arthropod food chains in a one-year experimental field. Ecology h8:75-83. Williams, A. B. 1936. The composition and dynamics of a beech-maple climax community. Ecol. Monogr. 6:318-h08. Willis, C. P. 191h. The control of rodents in field seeding. Proc. Soc. Amer. For. 9:365-379. VIII. APPENDIX A This appendix presents the results and discussion of the developmental study, emphasizing the radioisotopic uptake and location in pine seeds, and the transfer of radioisotopes into white-footed mice. VIII. DEVELOPMENT OF RADIOISOTOPIC TECHNIQUES FOR PREDICTION OF SEED CONSUMPTION A. Isotgpe Requirements Measurement of food consumption rates has been attempted using excretion or turnover of specific radionuclides in heterotherms. Excretion rates of radioisotopes in homeotherms have been employed to estimate body burdens, primarily to determine radiation dosages. Excretion of radionuclides has been correlated with many metabolic parameters in homeotherms, but has not been correlated with ingestion rate, and has been critically questioned as an indicator of metabolism in free-ranging mammals. Essentially no information is available on parameters of radioisotopic movement in homeotherms as a function of ingestion rate. Two radionuclide approaches appeared feasible for estimating food consumption in mammals. The first was dependent upon the concentration- factor concept where a readily assimilated isotOpe will build up in the body pool to an equilibrium level during chronic feeding. The second was a radiochemical-indicator technique using an unassimilated food tag and determining ingestion by differences in isotopic concen— trations in the food and feces. The latter technique was not examined, but the first technique was modified to include two isotopes, so that if the first approach did not work, the second could be examined. One isotOpe, with virtually complete assimilation, would be used as an 131 133 attempt was made to reduce this potential error as much as possible by Obtaining seed coats with radioactive levels similar to levels in endosperm. An acid leach was used to determine if seed coat radio- activity could be removed without a substantial loss from the endosperm (Fig. A-1 and Table A—l). The excess seed coat radioactivity was re- moved by a 1 1/2 hr soak in 1.0 N HCl, leaving a concentration equiva- lent to the endosperm. All seed coat radioactivity could not be removed without affecting endosperm concentrations. A 2 1/2 hr leach 137 began removing OS from the endosperm. A second radioisotope was required for the study as a gastro— 65 intestinal or food tag. A literature survey eliminated Zn, due to its immobilization in hair (Rice, 1963; Strain pp_g;,, 1965) and its rapid leaching from seeds (Radvanyi, 1970). The remaining isotopes SA 22 60 were Mn, Na, and Co; all were examined for conformity with 137 the action of Cs in pine seeds (Tables A-2, A-3, and Fig. A—2). As the total radioactivity taken up by seeds differed greatly, all data were expressed in terms of percent retention (Fig. A-2). A 5A high retention was Observed for Mn and was probably due to the very low radioactivity of the soaking solution, which was 0.00h5 uCi/ml compared to the other solutions with 0.5 uCi/ml. Thus, a greater 5h Mn was "bound" to the seeds, in comparison to the SA percentage of other solutions. The high cost of Mn (approximately $125/mCi), combined with a need for mCi quantities of isotope, necessitated re- 2Na) . . . . . . . 2 moval of this isotope from conSideration. Radioactive sodium ( was also removed from consideration due to its erratic behavior in seeds, very low uptake during the soaking procedure at similar specific 13h .Hl.<. 0H0.0.H. 80.5 .0909 .0003 0300.00.- 08 80 z 04 ea 00% 000 an m: 00.H Hum 0.30 00 0000000 00000 0.00.930 035m sop.“ worms” mo 00>080m .HLq 0.060% :5 .01 \< O... z. omx> !/ .A // \Dnul 00. d .0. N v m 135 .0000000 000 00 0000000>0 .m .m 029 .000000000 w0000000 000 00 00003 000 00 000000000 0000 0000 0000000 00000000000 000000 09 000000 .w00p0000 mo 0000000m m00m0000 00 000 0000 00003 x 0000 0000 + 00000000m0 0.o pm 0.0 00 0.0 00 om m m\0 0.0 mm 0.0 000 0.0 000 om 0 m\0 0.0 000 0.0 000 0.0 000 om 0 m\0 u.. In: In- In- 00 000.0 00 o m\0 -u:.H 000.0 bwuu.H 000 00 .0 000.0 00 o o z 0.0 00:0 00000000m 80000000m 0000 00003 000d 00m 00 0.0 .0 0.0 000 x sa0v 0000 000 000>0000o0000 z 0000o0 0000 .00000 000000> 000 00m 2 0.0 00 0000 000 00 M\0 000 00m 0000 00 000000 00000 0090000 00000 0000 00>m0 00 00>080m .0I< 00009 136 .00 :m 00 000090 8000 000080000 h00>00000000m0 .0000900 00000 0000 000000 00000 0003 0000800 00000 000 .000 00 00000 00030000 0000003 00000000 0000000 0000000 8000 00>0800 00000 00000 50000000880 008000000 0000 0000 .800000000 000 0000 0000 0000 000000000 000 0000mm u- -u -- -u 00.0 00.0:0 00 0 mm n- u- -- -- ::.o 00.:0 00 m\0 0 0: -- -- -- -- 00.0 00.00 00 0 0: -- -- -n u- 0:.0 00.000 00 0\0 0: -- -- -- -u- 00.0 00.0: 00 pm\0 0: -- -n -- -- 00.0 00.00: 00 o 0: -n -- -- -- 00.0 00.000 00 o :0 00 00 -u -- -n -- 00.0 00.00 00 m\0 0 0: 00.0 00.00 00.0 mm.m0 0:.0 :m.mm 00 0 0: 00.0 00.000 00.0 00.00 0c.o 00.0:0 00 m\0 0: m0.c m0.00 mc.o 0m.0 00.0 00.00 00 pm\0 0: 0:.0:0 0- o 0: -- n-u -- -- 00.0 mo.000 00 o :0 02:0 -u- -- n- -n 00.m mm.wom.m 00 o 00 00.0 00.000 00.0 m:.:m 00.0 00.000 00 m\0 0 0: 00.0 00.000 00.0 :0.000 00.0 00.0:: 00 0 0: -- -- n- -- 00.0 :0.000 00 m\0 0: -- -u -- -- 00.0 00.:00 00 pm\0 0: -- -- -- -- 00.0 mm.0mm.m 00 o 0: -- .I -n -u- I. -- 0m.c :m.0:m m 0 :0 00.0 + 00.0mm 00.0 + cm.mm 00.0 1.00.000 m m\0 :0 -- u-u -u 0-- 00.0 + 00.mmm.0 00 o :0 0000 :0 7:: A05 0000 0000 800Q0o00m 0000 00003 0000 00000 000000 0.0 .0 0 0 000 0 0000 0000 000 000>0000O000m 000000 0000 0000 0000000 .0000 000 z 0.0 00 0030800 0000000000 000 00000 0000000 00000 00 0000 000 .020m .0000 00 000000080000 .ml< 0000B 137 Table A—3. Percent retention of l37Cs, 6000, Sth, and 22Na by Pinus strobus seeds soaked in 1.0 N HCl for various periods of time. Time Soaked Retention (%) in Acid (hr) lBTCSa 60CO 5th 22Na Pure 1.0 N 0 0 100.00 100.00 100.00b 100.00 1/3 0 h3.62 ———C -—- ——- 0 1/2 —-— 39.28 59.3h 31.8h 0 1 —-- 18.70 3h.72 13.02 1/3 1 10.70 _-_ ___ ___ 0 1 1/2 --— 10.02 20.55 17.81 1/3 2 9.79 --- --- --— 1/3 3 3.33 --- --— --- aSeeds soaked only 28 hr in the 137 soaked for h8 hr. b 5h Value for time 0 was estimated from 2h hr uptake of 'Mn. CNot sampled. Cs solution, all others were 138 100 \Q 80 \\\ \ \‘ so \\ \ \\\ \ \ \ ‘ \ \ \ \ 1 4o \ -. §:° \ s \\ \~ x \ \ \54 20 Mn \\ 22 \ \ / Na \ ‘ / \/ \ \ \/ \\ \ 137 so ‘0 CS \J Co > 1/2 1 We TIME SOAKED IN 1.0 N HCI (hr) Figure A-2. Percent retention of 13703, 6000, Sth, and 22Na by Pinus strobus seeds soaked in 1.0 N HCl. Data from Tables A—2 and A-3. 139 activities, faster leaching during the acid soak, and high cost (ap- proximately $300/mCi). 137 Behavior of 6000 was similar to that of Cs in pine seeds. Both radioisotopes were absorbed and/or adsorbed by seeds at similar rates during both uptake and leaching procedures. The only apparent difference was a greater loss of 60Co from endosperm during the acid leach. Comparison of isotope retention between seeds which were dried before acid leaching and those which were subjected immediately to the acid leaching (Table A-2) indicated that seeds should be dry before the acid-leaching procedure. The HCl acid leach was changed to a H280LL leach in order to approximate normal pretreatment procedures for breaking seed-coat dormancy (USDA, l9h8). 137 Two trials of concurrent Cs and 60Co uptake were conducted (Table A-h). The first soaking solution contained 279,500 dpm/seed 137 of Cs combined with 20l,h00 dpm/seed of 60Co in 200 ml of distilled water. Concentrations of both isotopes increased in seeds through time. The Cs/Co ratio in seeds declined with increasing time, in- dicating a preferential uptake of 60Co. A problem with this trial was the changing concentration of both isotopes in the soaking solution as seeds were removed through time. The second trial was conducted while attempting to maintain a constant radioisotopic concentration per seed in the soaking solution. 137 This solution contained 87,200 dpm/seed of Cs combined with lSO,h00 dpm/seed of 6000. In this instance the seeds gradually de- 137 . . . 6O . creased in Cs concentration while Co increased; a reversal of 137 the Cs pattern observed in the first trial. Combined radioactivity 1h0 .moamamm cfl woosaosfl mommm manmfl>coc ow map mpw>flpowoficmh ooom swamp .pcmamhdmwmfi .m .w oz .cofipSHOm 8099 mommm Cw oxmpms pcoogmm O .HmbpopCfl mafia nomm pm ©o>oSmh mommm hog UmpoohAOo was mcowpdppcmocoom mH.mH mm.nu mm.om om.mm :;.o mm.wma mm.mm mm.o m:.0mfl sm.~m cm as mm.OOH mo.mm sm.o wom.sea aa.om mm.o m:.omH mm.~m OH ms 0:.mm om.om m:.o mm.mma :H.mm mm.o m2.0ma om.sw OH m: sm.wafl mm.Hw c2.o c:m.msa mm.o~ mm.o m;.oma :m.»m OH gm 1.. o--- mm.ms mc.mo as.o :m.maa sm.om mm.c m:.oma mm.am ca ma flashy emmmuooom mm.mu w>.mu mm.ms sm.sfi :m.o mm.mwm m:.mma os.m :m.mmm :w.mo~ om ms mp.m+ wm.w+ mm.m® m~.mm am.o oo.mmH sm.flma 0:.H mm.wmm aa.amm cm as mm.m+ mm.m+ mm.mm om.mm mm.o mo.maa mm.mm om.a mm.aom mm.m~m on gm aways emmwncom ooom moama 000m mosma Aggy capam A.m .m H + capmm coco mosma oo\mo emmm\mOH x easy 00\mo Aemmm\mOH x eaev emxmom QAwV mxmpm: COHpmhpcmocoo comm wQprwhpcmosoo Sofipsaom 2 mafia .moEHp mSOHhm> hmpmm mommm mSQthm mdcflm macs: up ooom cam mowmH mo coflpwasafioow pcmshSocoo .:I< candy 1A1 of both isotOpes at h8 hr was within 1% of the combined radioactivity at 18 hr, but the Cs/Co ratio decreased from 0.71 to 0.hh. This result also indicated a greater affinity of seeds for 60Co, with a gradual replacement of 13705 by 60Co. 137 On the basis of these findings, Cs and 60Co were selected for use in the study, provided that they would transfer into the white— footed mouse. All seeds were to be soaked at the same time in the dual-tagging solution for a period of MB hr, followed by air-drying for one afternoon. After one week of cold storage, all seeds were to be soaked in 1.0 N H2SOh for 2 hr, followed by air—drying of the seed down to 5% moisture content before subsequent storage at 5 C. C. Estimated Seed Supplies Required for the Study Quantities of seed desired for the study were based upon supplying one-third of the daily food requirement for an average population of small forest mammals on M ha of land. Reliable density estimates for white-footed mouse populations range from 7 to 27 per ha (Snyder, 1956; Stickel and Warbach, 1960). The extra food would support a higher population, and 30 mice/ha was used as the population estimate. To determine the seed weight consumed per mouse, a single white- footed mouse was fed 3,600 uncontaminated seeds over a 2l-day period. Periodically, uneaten seeds, seed-coat fragments, and excreta were collected, separated, and weighed. Remains of entire seeds could be identified in the fragments, and accounted for 98% of the seeds which were eaten. Of 2,037 fresh seeds consumed by this white-footed mouse, 63.5% was endosperm. Air-dry weight of 100 undamaged endosperm shelled 1h2 by white-footed mice was 10.83 mg, or 59.h% of the mean whole seed weight. It appeared that approximately h% of the seed coat was con- sumed by white-footed mice engaged in shelling white pine seeds. The percentage of endospermous tissue determined from this study agreed favorably with Abbott and Quinks' (1970) value of 66% for the same species from Massachusetts. Other studies with the same genera have resulted in values of 71% (Turcek, 1956), and 73% (Grodzinski and Sawicka—Kapusta, 1970; using oven-dry weights). This same 2l-day feeding study with the white-footed mouse was used to determine a daily ingestion of 97 seeds/day in the laboratory. Abbott (1961) reported an average of 109 seeds/day ingested by five white-footed mice during lhO days of laboratory feeding. Conversion of these ingestion rates to percent of body weight ingested per day gave 7.6% for the 21-day feeding trial, and 10.5% for Abbott's (1961) study (a 20 g mouse assumed for this case). These values are com- paratively lower than published values of 10-29% (Gorecki and Gebczynska, 1962), or A.7-31% (Turcek, 1956) of body weight ingested per day by European mice and voles of similar size. The average food ingestion rate from the latter two studies was 15% of wholeébody weight and was used to estimate a yearLy average of 3 g of food consumed per day by 20-g white-footed mice under field conditions. To supply a popu- lation of 30 mice per hectare, on two 2-ha field plots, with l/3 of the total food requirement, or 1 g per mouse-day, I estimated that the one-year study would require hh kg of pine seeds. This quantity was increased to 59 kg to allow for adjunctive feeding trials in the laboratory. 1113 D. Effect 2£_Acid-leached Seeds 2n_Ingestion This feeding trial was to determine how important the acid-leaching procedure was in contributing to the total consumed radioactivity by white-footed mice. Four male mice were each fed 50 dual-tagged seeds during a single feeding (Table A-5 and Fig. A-3). Two mice were fed acid—leached seeds; the remaining two were fed seeds without the acid 137 leach. Mice fed nonleached seeds, with 6.0h times as much Cs, in- 137 gested 1.53 times more Cs than mice fed acid-leached seeds. Simi- larly, 60Co, with h.35 times as much radioactivity in nonleached seeds, was 1.5% times greater than in mice fed acid-leached seeds. As the endospermous radioactivity was not changed by the acid-leach procedure (Fig. A—l), the increased radioactivity ingested by mice fed nonleached seeds indicated the importance of the ingested seed coat radioactivity. Although mice fed nonleached seeds did consume approximately 50% more radioactivity, it was not in proportion to the amount available. The delay in 60Co excretion, exemplified by the abrupt change in slope at day 1, indicated that some of the excretion pathways had not achieved normal rates of excretion (Fig. A-3). As 60Co was excreted primarily in the feces, in contrast to the urinary excretion of 137Cs, it was assumed that the delay was due primarily to the gastrointestinal turnover rate. In this case, the turnover took more than one day, which was the sampling interval. This assumption was supported by the inversion of the acid-leached versus nonleached groups of mice at day 2 (Fig. A-3). The cause appeared to be the ingestion of seed coat fragments with a lower assimilation than the endosperm. Higher .cmmm Umpmohplcwomuwwmw omnowwacoc mo 033mm.mW no.0 mH.H mo.m mH.o Ho.H mm.mH .o mm.o Jam No.0 HH.H mm.om NH.o me.m Hm.mm .o Ho.m gm: Hs.H H:.H mm.mw mm.o mm.mm mm.mm .o :H.om mmH mH.H Hm.H mo.mOH m:.o :®.mm mm.mHH .o ms.mm mHH mH.H mm.H mo.mw mm.o mm.me ms.mOH .o 0:.sm mm mm.H om.H mm.mm mw.o PH.sm mm.Hw .o mm.se so ms.o om.H Hm.mH mm.s mm.mm mm.Hm .m mo.om o; mm.H os.H mm.H em.mm :p.mm mm.H :m.~m e:.ms mH :m.H mm.H dH.H oo.OOH oo.ooH mm.H oo.ooH oo.ooH o Aggy esHe ARV coflpcopom H.mH w.mm :.m :.ma A&V soflpmmmcH AmOH x amev mm 2m.H mm.H mH.H 0mm HHm mm.H mos was eoHpmemeH OH x emev teem eH mm.e so.m Hm.o sme.H amm m:.o me.s :mH.m spH>HpodOHeem Hepoe ampH coHpmwmsH oprm eneem doom moemH 00\mo ooom mosmH 00\mo doom mosmH eanz co oHpem eetm eepdegpueHo< eeem edgeeeHeoz .momom mSQOMpm mdcflm oopmopplwwom no vmzowoasos mo mafiommw hmoImco hmpwm msmoodma mSszEOMmm hsom cw 00 was mo mo coflpcopmh was COHpmoqu .ml¢ magma ow 100 50 20 IO RETENTION (%) .0 U1 0.2 0.1 0.05 0.02 0.01 1h5 — ACID LEACH -- NO LEACH 4 8 12 16 20 24 28 TIME (days) Percent retention of 137Cs and 60Co in Perogscus leucopus after one-day feeding of Pinus strobus seeds. Comparison between mice fed with seed leached by 1.0 N HCl or with unleached seed. Data from Table A-5. 1116 radioactivity of mice fed untreated seeds indicated that a combination of assimilated and unassimilated radioisotopes were contained in the seed coats. Presumably, for mice fed acid-leached seeds, very little seed- coat radioactivity was removed by the 0.5% HCl digestive juices of the mouse (Prosser and Brown, 1950). After the seeds passed through the 1.8% acid-leaching solution, most of the remaining seed coat radioactivity would not have been readily removed by the lesser acidity of the digestive tract of the mouse. For mice fed nonleached seeds, the higher radioactivity was apparently due to the amount of radioactivity leached by the digestive fluids, combined with an additional quantity of unavailable radioisotopes which just passed through the digestive tract. This unassimilated portion was the quantity which would have been removed by the acid-leach procedure, but was not removed by the 0.5% digestive fluids of the mouse. Ex- cretion in mice fed nonleached seeds paralleled that of mice fed acid-treated seeds except for higher quantities of radioisotopes in the whole body during day 0 and day 1. Thus, in order to minimize the potential influence of seed-coat radioactivity and to reduce the total amount of radioactivity released into the environment, the acid leach was applied to all seeds prior to the start of the study. E. Isotopic Transfer from Seed.tg_Consumer Another test was conducted with four male mice chronically fed lOO dual-tagged pine seeds per day for 1h days and subsequently ex- amined for 106 days during excretion (Table A-6, Fig. A-h and A-5). 1h7 Table A—6. Whole-body accumulation and excretion of 137Cs and 60Co in Peromyscus leucopus during and after lh—day chronic feeding of Pinus strobus seeds. Day Radioactivity (dpm X 103 :_1 S. E.) Cs/Co Retention (%) 137Cs 6OCo Ratio 13705 60Co Uptake phase 1 168.72 :_ 23.08 1hh.h3 1, 2.32 1.17 ---a --- 2 290.53 15.h6 190.23 15.81 1.53 —-- --- 3 hoh.o3 35.80 182.61 32.6h 2.21 --— --- h h97.11 50.3h 201.55 37.58 2.h7 --— -—- 6 602.88 36.69 217.3h 36.hh 2.77 —-- --- 8 695.05 5h.7h 269.1h h5.33 2.58 --- --- 10 725.57 52.13 223.h8 31.h6 3.25 --- --— 12 729.23 80.80 261.15 h6.28 2.79 --- ——- 1h 722.12 79.8h 2h1.96 33.90 2.98 --- --- Excretion phase 0 722.12 :_ 79.8h 2h1.96 :_ 33.90 2.98 100.00 100.00 1 577.82 76.02 6h.33 28.02 8.98 80.02 26.59 2 508.98 70.52 27.02 8.81 18.8h 70.h8 11.17 3 h11.39 60.59 13.55 3.21 30.37 56.97 5.60 t 363.25 58.06 9.5h 1.20 38.07 50.30 3.9h 5 317.78 5h.77 8.30 0.53 38.30 hh.01 3.h3 8 191.09 36.32 8.21 1.02 23.27 26.h6 3.39 9 168.97 3h.2u 5.12 0.35 32.97 23.h0 2.12 12 115.73 2u.83 5.38 0.53 21.53 16.03 2.22 15 80.7h 19.50 7.67 3.39 10.53 11.18 3.17 22 28.51 7.38 3.32 0.32 8.57 3.95 1.37 29 12.37 2.96 2.83 0.29 h.37 1.71 1.17 36 7.52 1.55 2.38 0.10 3.16 1.0h 0.9a M3 5.31 1.0h 1.88 0.16 2.82 0.7h 0.78 57 2.83 0.52 1.55 0.0u 1.83 0.39 0.6h 106 1.08 0.30 0.85 0.05 1.26 0.15 0.35 8Not applicable during isotope uptake. 1h8 106 8 M 6 t/ 43%35 4 60 Co a””” WHOLE— BODY RADIOACTIVITY (dpm) o 105 O 2 4 6 8 IO 12 I4 TIME (days) Figure A-h. Accumulation of 137Cs and 60Co in Peromyscus leucopus through fourteen-day chronic feeding of Pinus strobus seeds. Data from Table A-6. 1h9 .mn¢ mewB scum spam .mhwu smmphdom Mom momma mapoupm macaw ommwdp Mo sowpmmwna oHcouno nmpMd mSNOOSmH macawaonmm an 00 and worm:H mo sofipsmpmm .m|< mhswwm om 363 m2: 0:. 00.. 0m 0m Ox. 00 00 CV Om ON 0.. o to 0/ / Nd / CI 1 I Iiily /I/. no I." / I.,! r '0’”. / H / iooow m H. ‘v. / ,1 N. ,. m. l Th1 nlu .. m N Sharer " Wm a : 0. ON .u. / 3. F on d _ 00.. 150 137Cs after 1h days was h.3 times the daily ingeStion (predicted by the day l radioactivity), and 1.7 times for 60Co. Accumulation of Equilibrium, when ingestion was equal to excretion, occurred after 137 10 days for Cs. Equilibrium probably was not attained for 60Co in this experiment, Judging from the results of Smith §t_al, (1971), but the body burden did not appreciably change after day 8. As- 137 similation was nearly complete for Cs, and.epproximately 2% for 6000. Fluctuations in the 60Co radioactivity during uptake were primarily due to the mode of excretion. It would have been necessary to count mice for radioactivity at the same time, relative to their digestive processes, in order to smooth out the 60Co curves. Al- though mice were fed at 1800 hr each evening, and counted from 0900 hr to 1130 hr each morning, individual variability in eating habits and rates of digestion of the mice created the problems in determining OCo equilibrium after the first day of ingestion. This problem did 137 not occur with Cs due to its high assimilation by mice. The soft 137 tissues effectively integrated the Cs body burden and smoothed the resultant curves. Results of these feeding tests indicated a favorable 137 transfer and accumulation of Cs in the soft tissues of mice. The food tag, 6000, also appeared to transfer satisfactorily. F. Isotopig_Retention pf Chronic Versus Single Ingestion Fecal excretion was examined to determine the pattern of excretion after single-feeding and at the end of the uptake portion of the chronic- feeding test (Fig. A—6 and Table A-7). After termination of chronic 137 feeding, fecal excretion of Cs was constant through the first few 10" 103 RADIOACTIVITY PER FECAL PELLET (dpm) 151 SINGLE FEEDING FEEDING ’ 10' 16 4O 64 88 112 16 4O 64 88 "2 TIME OF FECAL COLLECTION (hr) TIME OF FECAL COLLECTION (hr) . . 137 60 Figure A-6. Fecal excretion of Cs and Co by Peromyscus leucopus after consumption of Pinus strobus seeds for one or fourteen days. Data from Table A—7. 152 137 60 Table A—7. Fecal excretion of Cs and Co by four Peromyscus leucopus after consumption of Pinus strobus seeds for one or fourteen days. Time of Number of Fecesa Radioactivity per Fecal Pellet Fecal (total :_1 s. E.) (dpm :.1 s. E.) 3333:3333 One day 16 72 :_ 12 209 :_ 11h 1,h10 :_ 395 no 127 19 79 29 1,567 h08 6h° 109 21 70 2h 56 1 88 106 8 66 8 i 11 1 112 120 8 53 16 12 6 Fourteen day 16 250 :_ 20 217 :_ 3h 2,528 :_ 550 ho 126 in 181 21 1,590 268 6h 179 2h 170 37 256 120 88 138 23 190 MB 1ho 57 3Number of feces collected per period. bTime after last feeding of tagged seeds. N=3o 153 days, while 60Co was initially much higher (11 times greater than 137Cs) 137 and then rapidly decreased to a level consistent with Cs. This de- crease had occurred by 6h hr and was indicative of the gastrointestinal clearance of radioactive foods. An hourly collection of feces would have been necessary to determine this parameter more accurately. How- ever, this turnover time was similar to that of another cricetid, Sigmodon hispidus, with a 66-hr turnover (Kitchings g§_§l,, 1969). Wholeébody retention of both radioisotOpes was greater after chronic feeding than single feeding (Figs. A-3 and A-5). Differences, by day 137 22 of excretion, amounted to 2.8 times more Cs retention and 8.5 times more 6OCo retention in mice fed chronically compared to those fed once. These wholeébody retention differences may reflect the im- portance of various uptake compartments in the body. Those compartments which cycle elements slowly would not acquire significant radioactivity during the short period of access during single-feeding experiments. Thus, if these slowly—cycling compartments have not acquired a pro- portional share of the wholeébody radioactivity, the excretion must reflect those faster-cycling compartments which did acquire a significant amount of radioactivity. Excretion curves for single-feeding experiments with mice should reflect faster excretion rates than excretion curves for chronically-fed mice, as was shown for these feeding eXperiments. IX. APPENDIX B The following series of tables and graphs were deemed of sufficient importance to include in the thesis as an aid to the explanation of text figures and tables. 15h .mamgm mop hound uwuwpsmo Macaw aoppom p .hwv pom wow mvomm mo nonadzO thmmm SOBfiom mdmmm mOB Hoapaoo I OH 6H6: I Om “6an I OOH can I m cHnsca I OH cHnscm I Om cHnaca I OOH Honpsco I m cHnacm I OH can I Om 6an I OOH 6H6: I m .3an I OH cHdscm I Om Honpsoo I OOH cHsacm I m 6H6: I OH 6H6: I Om cHssca I OOH 6H6: I m 6H6: I OH Hoapaoo I Om 6H6: I OOH Shana I m cHnsca I OH cHeaca I Om cHnsca I OOH cHnscm Ism .nmnamno HspcmaqonH>nc map sH sofipsooq .GOHpscHnEoo pstpwmsp mode cm mmmmmmMfl.mmmmxmmMMM asswfi>fldnfl How :mHmmw whdfidm :prH Omfimfldoz .Hlm mhdmfim 155 12- I L seeds/day E H 100 O. !. r 13 ___ :c. 50 2 I0 _ 2 a: ‘2 _J 55 9 8 1*? H 10 >.. !— ——i o f C) 8 II: III _J ‘1’ g 7{ H— 2 6 4O 50 60 70 Figure B-2. TEMPERATURE (°F) Whole-body equilibrium in Peromyscus leucopus as influenced by temperature and ingestion rate. Data from Table 1. .mmIm chna scam 33 .83 Co moowumm wsoa you Ummgshp pom mack Sumss mawafiqs pomscoo momma cognac .mwmmm_mmmmmmm mssflm wswcmmm mo mxmmk mm pSOQwsonsp scam OHme mahplm>HH onu aonm_mmmmmmMfl mSUmhaopmm Hadombfiwsfi How mommaH mo sounds hoonImHosz .mnm mhsmfim Ohm. amm— < H. a .2 < .2 n. 1 o z O m <1 7 156 (b/wdp) All/\IIOVOICIVU mos-310m 50,3, M/Il o I... IIIIIIINIT km I \\ I1/M¢/x\\ MI I . a \ < a \ WI 8. \.\ > K 0 m8 0 9 4\ \ //O vb 08 d x .M “Woo m 09 o .b moo o . _ _ Amo_xv .wmlm OHQBH. 80h.“ damn .mEHB mo mvowhmm maoa no.“ @9395 #0: who: £9.53 3.25:8 vowcsoo mos: @0593 .303 a 3ch wagon.“ mo mxmms mm 93085083 podm can: mauplmar: map Eon.“ wusmofemho. g stwflaficnw no.“ wormH mo Gouge. 80033”an .zlm mafia Em. mmm . < a _.. .2 < .2 m H. o z O m < .1 /‘ L\ I I/ \% I I O 157 .INIWIIIJIIE/ (IlselllelH 1W. dawns. /7 / \ .... \ax \\/ )1/ x. / \ \ .7 On \m .I.\ p/ /V\/_ a o BI / \ a/ was a a 1I \L\ w L.O ml 00’ i .00 mo vampmcfl 2 >80 mdwmm .HO .HmDhH—AQ " .omamadm p020 .mH moo 6o omopmsH mH ammo Q mpwn compmmmsHm 0H.0 0H.0 0H.0 mm.0 02.0 02.0 02.0 00.0 H0.0 mm.H 20.0 m2.m 00.0 H0.0 mm.2 0m.H 0.mH ado: mH.0 2H.0 0H.0 0m.0 00.0 00.0 00.0 00.0 mm.H 02.m mo.m mm.0 00.0 00.0 mH.2 m2.H H.Hm 2H.0 Hm.0 0H.0 0m.0 mm.0 «0.0 02.0 mm.0 H0.0 mm.H >>.m 22.m 02.0 00.m 00.0 0H.H 0.0H No.0 00.0 00.0 mH.0 mm.0 0m.0 00.0 00.0 00.0 20.0 0m.m m0.m 00.0 Hm.m m0.a >~.0 0.0H 0H.0 HH.0 0H.0 >H.0 00.0 0m.0 02.0 02.0 >0.0 mm.H 20.0 No.2 00.0 0H.0 mm.m 00.0 2.2 00H 0m.0 mm.0 Pm.0 H0.0 >2.0 00.0 0m.0 00.H 00.H No.0 m0.m 02.» m~.0 00.0 00.0 2m.H H.Hm mm.0 mm.0 00.0 mm.0 00.0 Hm.0 m0.0 0H.H 00.H 00.0 0>.0 2m.m mm.0a 0m.0 00.m 2m.H 0.mH 0H.0 NH.0 2H.0 00.0 22.0 2m.0 00.0 20.0 mH.H 2H.m 2m.2 0m.m 00.0 mm.2 0H.0 0H.H 0.0H 2H.0 SH.0 NH.0 0m.0 00.0 m2.0 00.0 02.0 0m.0 2H.H mm.m 00.2 00.m 0m.2 00.0 0m.H 2.2 0m 0m.0 0m.0 00.0 H2.0 mm.0 20.0 0H.0 0m.H 2m.H 00.m NH.0 m0.» 00.0 mm.0 mm.m m0.H H.Hm 0H.0 0H.0 NH.0 0m.0 0m.0 mm.0 H0.0 00.0 mm.0 00.H ~2.m m>.m 20.m mm.m 00.2 02.H 0.ma NH.0 PH.0 0H.0 0H.0 00.0 H0.0 00.0 02.0 H0.0 00.H NH.m 0m.2 m0.m 0m.2 00.m 0H.H 0.0H Hm.0 mm.0 mm.0 0m.0 02.0 0m.0 m2.0 S2.0 0m.0 No.0 2m.m H0.0 H0.2 Hm.2 no.0 00.H 2.2 0H PH.0 mm.0 mm.0 00.0 02.0 00.0 02.0 00.0 00.0 00.H 00.2 H0.0 00.0 00.0 00.0 m0.m H.Hm 0H.0 Hm.0 0H.0 mm.0 20.0 m2.0 20.0 00.0 00.0 0m.H 00.0 m0.m H0.» 00.» 0H.0 20.m 0.mH 0H.0 0III 0m.0 mm.0 02.0 0m.0 2m.0 20.0 mm.0 00.H 00.0 0m.m 00.0 00.0 20.2 0H.m 0.0H HH.0 2H.0 0H.0 HH.0 00.0 m2.0 2m.0 mm.0 H0.0 00.0 00.m 0H.0 2m.2 0m.2 00.0 2m.H 2.2 m 00H m0 H» mm 02 02 0m mm mm ma 0 m m m H 0 on mopmm soapopoxm mo 000 @809 sowpmomsH Ao.psoov OIm oHnms 169 Table B-lO. Weights of organs and tissues of Peromyscus leucopus after M9 days of chronic feeding of Pinus strobus seeds in the laboratory. Organ or N Wet Weight N Oven-dry Weighta Tissue (g :_1 S. E.) (g + 1 S. E.) (%)b BloodC 16 0.58 :_ 0.03 16 0.12 :_ 0.007 l.h8 Heart 31 0.16 0.007 31 0.0M 0.002 0.5h Liver 31 1.26 0.05 31 0.37 0.01 h.81 Spleen 31 0.03 0.002 31 0.007 0.000h 0.09 Kidneys 31 0.32 0.01 31 0.09 0.003 1.1h Lungs 31 0.21 0.02 31 0.06 0.005 0.72 Muscle 31 0.11 0.00M 31 0.03 0.002 0.h0 Femur 31 0.06 0.002 31 0.0a 0.001 0.h6 Brain 31 0.60 0.008 31 0.1h 0.002 1.79 Testes 16 0.h2 0.03 16 0.07 0.00h 0.92 onudes 13 0.02 0.00h 13 0.008 0.002 0.10 Epidmmmns 13 0.58 0.06 13 0.23 0.02 2.98 Urogenital 15 0.18 0.02 15 0.06 0.01 0.8M Bladder 15 0.02 0.00h 15 0.006 0.001 0.07 Skin 31 2.79 0.09 31 1.61 0.07 20.7h Carcass 17 10.1h 0.32 31 h.26 0.18 55.02 Stomach 30 0.u1 0.02 30 0.07 0.002 0.88 Sm. intestine 31 0.29 0.02 31 0.0h 0.002 0.51 Lg. intestine 31 0.15 0.006 31 0.02 0.001 0.32 Cecum 31 0.15 0.007 31 0.02 0.0005 0.23 Gastrointestinal contents: Stomach 20 0.59 0.05 31 0.25 0.02 3.21 Sm. intestine 19 0.83 0.0h 31 0.13 0.006 1.68 Lg. intestine 20 0.38 0.03 31 0.13 0.01 1.69 Cecum 19 0.6M 0.05 31 0.15 0.009 1.87 Totals: Tissue 17 18.0h 0.52 31 7.09 0.26 91.53 Gastrointestinal contents 19 2.h3 0.1h 31 0.66 0.03 8.h7 Whole body 31 21.95 0.h8 31 7.7h 0.27 100.00 aDried for a minimum of h8 hr at 50 0. Organ or tissues percentage of total oven-dry weight. Sample of blood, not total amount. Gastrocnemius muscle only. c d e Residual carcass after removal of listed organs and tissues. 170 Table B—ll. Chi-square test of radioisotopic distribution in organs or tissues of Peromyscus leucopus after h9 days of chronic feeding of Pinus strobus seeds in the laboratory. Organ or 137Cs Chi-square 6OCo Chi-square Tissue Observed Contribution Observed Contribution Ratioa Ratioa Bloodb 0.A3 0.33 0.38 0.39 Heart 1.50 0.25 O.hl 0.35 Liver 1.07 0.01 0.82 0.03 Spleen 1.33 0.11 1.h2 0.18 Kidneys 1.86 0.7h 1.53 0.28 Lungs 1.06 0.003 0.38 0.38 Muscle 2.71 2.92 0.30 0.50 Femur 0.57 0.18 0.32 0.h6 Brain 1.10 0.01 0.08 0.85 Testes 3.10 h.u1 0.h6 0.30 Ovaries 0.92 0.007 1.21 0.0h Epididymis 0.h6 0.29 0.16 0.71 Urogenital 0.81 0.0h 0.29 0.51 Bladder 6.38 28.92 2.5h 2.36 Skin 0.38 0.38 0.08 0.8h Carcass 1.16 0.03 0.10 0.80 Stomach 0.93 0.005 1.0h 0.001 Small intestine 0.88 0.02 1.hh 0.20 Large intestine 0.88 0.01 2.00 1.01 Cecum 0.7M 0.07 2.92 3.68 Gastrointestinal contents: Stomach 0.80 0.0h 16.1h 229.1h Small intestine 1.72 0.52 1.81 0.65 Large intestine 1.75 0.56 22.72 h7l.9l Cecum 1.13 0.02 32.6h 1,001.20 Total: 39.86 1,716.77 Total without bladder: 10.95 Total without gastrointestinal contents: 13.87 aRatio is (percent of isotope in sample/percent of total body weight in sample). bSample of blood, not total amount. 0 . Gastrocnemius muscle only. dResidual carcass after removal of listed organs and tissues. 171 .H2Im 0Hp0e 0H umpmfla 050 0050: owmmps0fiom .poam 0H0H0 m0nplm0c0 u pl0 000 mm0hpu0>fia u pIq ”HOMQGOO u 500” H} II “H0poe 820 50030 p5sa03 xo0am hhoxofin 25090030 200 005 550£p5o0 550:02059 0QHH0500 EH0 xoom 5H0 c0oflh0a< hhh0thQ0z S00pchongom 0QHQ mpfins G50p00m 059005 550pr0 000 900m 0Hmm0n050 055050 Mo0am coaaw050m >550QH5E 00m 005000000 00050 uawz 00o 55050030 0QHQ m00pro30 hpoxOHn p5sp0xoo2 :00 0pH£3 voosmom 00o Mo0Hm 0HQOS 00m aaoaoHs pscmHm 0Hm0a 50050 00ozh500 0H 200 05Hn3 00 OH Om an m 0H smHaoa soHHmw 0MI 0H 0H 0 0H NH 850 200Hm Hopoe pIm pIq ooO Hmpos pIm pIa coo Hanoe pIm pIq soO anoa pIm pIq soO H0poa 0.>m A 0.Nm Op 0.0H 0.0H Op 2.m A60 Ga npwv 000H0 0NHO D002.5000 I m H U\ H O\ mom m .3 .d' H ,d' H H (\I H 0 (\J (\J on O H O\U\(‘OCI)NNmm—II’Or—IOOI—Ir—Ir-IOI-IOOOOOOOOI—IOOOOW O H QCDb-mfimmmmmmr-Ir-II—Ir-Ir—II-Ir-II-IHHJ NNNONONNr—IMONI—IHI—IHHOOOOOM [‘OOWNMNNMONHr—IHI—IHI—IOOOr—I I—I 0H .3 H H .3" (\J (\I H H (DJ (\I CD!‘ (\IN LAN H H H U\ (\I JONNNOONONI—Ir—IO’IONr-Ir-II—II-II-IOOOOON H mm 0H mm m 00 MH ms HH 01 c>::Oxuxq>aluerc>oIrIc>rIrIc>rIc>c>c>c>c>c>c>rIrIc>rIww qu>ww «loIm raxora H .4 0: OJCDSzd)U\QDOJ£TC)C)0JFIC)r1C)CDCDC)CDCDCJCDCDCDCDCDCDF4U\ r—I \OLflJMOOmI—Ir-I(\IONOr—IHOOOOOOOOOr—IHI—IOW I—I 2H 00 ma CON C\IC\I (I) H OOMNOWOOONI—IFWOOOOOONOOOOOOOOOOOW I—I \Ol"\O(\J\OU\.:I'mJONmb-HMI—IOI—IOI—IOOOOOOr-IOOI—IOCI) O[‘OOOt—IOLflO(\IOQJOOOOOOOOOOOOOOOOOOON OOI—Ir—IOmOr-IOOI—IJLROOOOOOr—IOOOOOOOOOOOP— Ommr—IOr-IOMOOOr—IOOOOOOOt—IOOOOOOOOOOO ONMNI—I—dr-IOIOMOOOOOOr—IOOOOOOOOOOOOOO-d' NNNMJOI—Ir—IOOOt—INONOOOOOOOOOOOOOOI—IOW I—ILAP-HO0HFOOHOOOOOOHOOOOOOOOOl—It-Ioom m (\I H \O I 0.0poam 020wm 005:5 pom 000Ho 0Nfl0 hp 00fio0gm 0055 0o soflp5pwhpmwm .mHIm 0HQ0B Table B—l3. 172 Seasonal captures per 100 trap nights for Peromyscus leucopus, Blarina brevicauda, and Tamias striatus on the live-trap and control field plots. Period or Live—trap Plot Control Plot Season B._l_._._ 2.3;; _T_._s___ M 3.1.1:. §_._b_ T.s . Total Total captures Prestudy h.17 2.50 0.A2 7.08 2.50 1.67 0.00 h.l7 Uptakea 3.31 h.37 0.35 8.03 5.99 3.13 0.82 9.95 Autumn 1.63 6.03 0.50 8.17 6.90 3.37 0.16 10.h3 Winter h.58 9.15 0.35 1A.08 3.88 0.30 0.00 n.18 Spring h.hh A.AA 0.67 9.56 10.89 0.00 0.00 10.89 Summer 5.90 3.A9 2.h0 11.79 8.00 1.11 0.Ah 9.56 Excretionb 7.81 17.38 1.76 26.95 ---c --- --- --- Total: h.21 6.75 0.89 11.85 6.7A 1.91 0.32 8.97 Total individuals Prestudy 2.08 2.50 0.u2 5.00 1.67 1.67 0.00 3.33 Uptakea 1.h2 1.65 0.2A 3.31 1.09 1.63 0.27 3.00 Autumn 0.88 2.6h 0.50 h.02 1.93 2.09 0.16 h.17 Winter 2.11 7.1h 0.35 9.51 2.09 0.30 0.00 2.39 Spring 1.78 3.33 0.67 5.78 3.78 0.00 0.00 3.78 Summer 1.96 2.h0 1.31 5.68 1.78 0.22 0.22 2.22 Excretionb h.h9 7.23 0.98 12.70 ---° --- --- --- Total: 1.28 2.17 0.39 3.85 1.13 0.92 0.11 2.15 aPeriod from July 2h, 1969 to September 25, 1969. bPeriod from September 1, 1970 to December 10, 1970. 0No trapping conducted during this period. 173 Table B-lh. Recaptures of small mammals on the live-trap plot and control plot. Number Peromyscus leucopus Blarina brevicauda Tamias striatus Cagiures L—ta Con L—t Con L-t Con 1 25 8 30 1h 7 0 2 5 5 l6 5 2 1 3 5 2 l3 2 l 1 II 2 0 5 l 2 l 5 2 3 3 2 1 O 6 0 0 2 0 0 0 7 2 3 3 0 1 0 8 O l 1 0 0 0 9 l 2 2 0 O 0 10 0 1 O l 0 0 ll 1 l O O 0 0 12 0 2 3 O 0 0 13 0 l l 0 0 0 1h 1 2 O 0 O O 15 O 0 O O O 0 16 1 O 0 0 0 O 17 0 0 O O 0 0 18 1 0 O 0 0 0 19 0 1 O 0 0 O aL-t = live-trap plot; Con = control plot. 17h Table B-15. Weekly Pinus strObus utilization from feeders by small forest mammals on the live-trap and snap-trap field plots. Weekly seed weight fed = h35.2 g/plot. Week Date Total Utilization Eaten in Feeder Examined (%) (%) Live-trap Snap-trap Live-trap Snap-trap Uptakea b 1 7/31/69 12.27 h2.65 --— --- 2 8/7 26.95 85.55 -—- --- 3 8/1h hh.26 100.00 -—- 50.39 A 8/21 5h.69 100.00 --- 30.h7 5 8/28 66.ul 100.00 22.08 21.88 6 9/h 53.91 100.00 12.89 28.12 7 9/11 73.hh 100.00 16.02 22.27 8 9/18 88.28 100.00 22.27 19.15 9 9/25 66.80 100.00 12.11 15.23 Autumn 10 10/2 68.75 95.31 5.h7 10.55 11 10/9 78.52 97.65 6.25 8.20 12 10/16 59.38 92.58 7.03 5.08 13 10/23 70.70 90.2h 5.h7 3.91 in 10/30 69.1h 87.89 h.30 3.91 15 11/6 79.30 9h.53 3.13 h.30 16 11/13 81.6h 92.19 1.17 3.52 17 11/20 71.h8 89.h5 0.78 3.90 18 11/27 56.25 73.83 0.39 1.17 19 12/h 58.98 76.95 0.00 3.90 20 12/11 53.91 88.67 0.00 h.30 21 12/18 h7.27 7A.61 0.00 3.12 22 12/25 66.02 90.23 0.00 6.6M Winter 23 1/1/70 83.20 9h.53 3.12 h.30 2h 1/8 67.19 76.56 0.00 3.51 25 1/15 85.9h 92.19 7.A2 3.91 26 1/22 71.09 87.11 0.00 h.69 27 1/29 80.08 90.63 3.52 3.91 28 2/5 81.25 95.31 1.95 h.69 29 2/12 77.73 92.19 0.00 3.52 30 2/19 81.25 95.31 0.39 5.h7 31 2/26 70.70 91.80 0.39 h.30 32 3/5 67.19 9h.53 0.39 h.69 33 3/12 66.h1 92.58 0.39 h.30 3h 3/19 69.53 88.28 1.17 7.h2 35 3/26 63.67 80.08 0.00 7.03 Spring 36 h/2 72.65 91.h1 1.17 9.77 37 h/9 57.03 95.31 1.17 18.75 38 h/16 69.53 97.66 1.17 23.05 175 Table B-15 (cont'd) Week Date Total Utilization Eaten in Feeder Examined (%) (%) Live-trap Snap—trap Live-trap Snap-trap Spring 39 A/23 82.81 100.00 1.95 16.02 A0 A/30 83.20 100.00 A.69 6.6A A1 5/7 82.81 100.00 A.30 12.11 A2 5/1A 81.6A 100.00 10.16 1A.8A A3 5/21 85.16 100.00 11.72 8.59 AA 5/28 90.23 100.00 15.23 7.81 A5 6/A 95.70 100.00 9.37 10.9A A6 6/11 98.05 100.00 11.33 A.69 A7 6/18 9A.1A 100.00 12.11 3.52 A8 6/25 92.58 100.00 11.72 8.20 Summer A9 7/2 9A.53 100.00 1A.06 10.55 50 7/9 95.31 100.00 18.36 13.67 51 7/16 92.19 100.00 9.38 12.11 52 7/23 92.19 100.00 17.97 16.02 53 7/30 87.89 100.00 16.02 9.38 5A 8/6 91.A0 100.00 1A.8A 10.9A 55 8/13 9A.92 100.00 20.31 10.55 56 8/20 80.08 100.00 18.75 12.89 57 8/27 92.97 100.00 19.1A 1A.8A 58 9/3 79.30 100.00 19.1A 17.97 ExcretionC 1 9/10 9A.63 A.55 2 9/17 9A.7A 2.83 3 9/2A 92.56 6.61 A 10/1 98.1A 2.23 5 10/8 95.39 1.5A 6 10/15 95.A1 1.53 7 10/22 98.A9 1.50 8 10/29 95.88 0.00 9 11/5 96.90 3.10 10 11/12 96.23 5.66 11 11/19 91.73 A.35 12 11/26 95.83 A.52 13 12/3 91.23 6.32 1A 12/10 97.19 9.13 aPeriod from July 2A, 1969 to September 25, 1969. No data collected. .Nonradioactive sunflower seed used in feeders during the excretion phase in amounts equivalent to Pinus strobus seeds. No seed used on the snap-trap plot as the population of small mammals was removed at the end of feeding pine seed. Table B-16. 176 Comparison of visual estimation of feeder utilization to actual utilization. Estimated N Estimated Actual Utilization Remaining Remaining Class (g) (g :_1 S. E.) 0 Removal 195 6.8 6.60 :_ 0.02 1/A Removal 63 5.1 5.37 0.09 1/2 Removal 33 3.A 3.66 0.12 3/h Removal 39 1.7 1.97 0.1h 177 .00559000 0H0EH50 oz .wHoanHwbd HO.H.Hm UHwUQde OZ“. H0.0 00.H0 00.0 00.20 0 00.0 00.00 00.0H 20.00 m 002I202 H\0 mm.H 05.0H 0m.» 0O.m0 2 05.0 0H.00 m0.O0 2m.mm 0 msmI050 2\0 H0.0 2H.m0 H2.0 00.05 2 0H.0 m0.0H 00.0H 00.H0 m 0mmImmm 2H\m III III III . O 0m.mH 00.02 0H.20 m0.Hm 2 mmmI2mm m0\0 III 00.00 III 02.00 H mm.H 22.0H mm.HH OO.m2 2 2HmI0Hm 0\0 0>.m m0.m0 00.0 00.00 m 00.0 00.0 20.0 HH.om 2 000I000 0H\m H2.0 00.00 HO.H0 20.22 2 III 0m.HH III sm.mm H 0m0IHm0 H0\2 III 00.00 III 00.00 H H0.H 00.0 0H.HH 00.00 m 000Ihm0 0\2 00.2 0m.mm 05.00 22.0OH 0 0m.O 20.0 0H.0 00.0 m 000I000 m\m H0.0 H0.0 02.0H H0. 0 00.0 00.0 00.0 20.0 0 000 . 0H\0 III III III I 0 00.0 20.0 00.0 00.0 m 00HI~0H 0~\00\H H2.m 02.20 2O.m0 00.00 2 III III III III O mmHI0mH m\0H III 00.0H III Om.0m H III III III III O m0HI20H m0\HH H0.0 00.00 0H.0H 00.00 2 III 00.0 III 00.0 H HHHI0HH HH\HH 00.m 00.H0 00.0m 52.02H 2 m2.H O0.0 0m.m mm.20 m MOI00 00\OH Hm.m 00.20 00.H0 HO.00H m mm.O 02.0 m0.mH 5m.0m m 00I00 2H\OH H0.0 00.00 m0.m0 00.0HH m 0O.m 00.0H 00.0 00.02 0 0mImm 5\OH mH.m 00.5H mm.02. mH.mmH 0 Hm.m 5H.0H 00.02 0m.m0H 0 00IH0 m0\m 00.0 00.0H 00.H0 00.0HH 2 00.H 00.20 00.0H 00.00 0 02Ih2 0\0 00.0 H0.0H 00300 02.00 0 III 00.00 III 00.00 H H2I02 0\0 0H.2 00.0 20.00 00.00 m 00.0 00.0 00.0 00.00 0 mm 00\0 00.2 00.0H mm.H0 00. 0 III 00.2H III 00.00 H 00I00 0H\0 .III III III pI O 20.0 mm.HH 02.0 HO.22 2 O0ImH 0H\0 20.0 00.0 00.0 00.0 0 00.0 00.0 00.0 00.00 m 0HI0H m\0 III 0m0.0 mIII O2.O H m2.HH 5O.0H 0O.2 Hm.50 m OHIm 0\0 200.0 .I 000.0 000.0 .I 000.0 0 HO.H .I 00.H 00.2 I. 00.2 0 0 00\m 000.0 + 0H0.0 0000.0 + 000.0 0 0000.0 + 000.0 2000.0 + 000.0 m 0 00\20\> oOO0 mONmH z oOO0 mONmH z 50520 2.0 .0 H.“ m\mOH 5 0500 mosmoa>msp.qm 2.0 .0 H.H m\mOH 5 0000.0000000H.dm 0o 5mm 0560 .00000 0590590 055Hm 05H5H09500 90Hm 0H0H0 Q059I0>HH 099 50 00500H>059 05H50Hm 050 0590050H 0500080500 50% 00H50m 05H00059 50m 0000 050 00>0H 00 500559 0009 5002 .NHIm 0H908 178 Table B-18. Seasonal captures of individual small forest mammals on the snap-trap field plot. Period or Trap Capturesa Season Nights P.1. B.b. M.p. S.l. T.s. Total b Prestudy 380 2 O O 0 l 3 Autumn 38 0 2 O O 0 2 Winter 87 1 0 1 2 0 A Spring 58 l 0 5 l 0 7 Summer 58 5 6 0 0 0 11 Autumn 192b 8 13 2 0 1 2h Total: 813 17 21 8 3 2 51 Captures per 100 trap nights: 2.09 2.58 0.98 0.37 0.25 6.27 aSpecies are P.1. = Peromyscus leucopus; B.b. = Blarina brevicauda; M.p. = Microtus pinetorum; 8.1. = Sorex longirostris; and T.s. = Tamias striatus. bLive-traps used instead of Museum Special snap—traps. 179 Table B-19. Weights of organs and tissues of Peromyscus leucopus from the snap-trap field plot. Organ or N Wet Weight N Oven—dry Weighta Tissue (g i.1 S. E.) (a 1.1 S. E.) (%)b Heart 7 0.15 :_ 0.01 7 0.0A :_ 0.00A 0.6A Liver 7 1.06 0.20 7 0.30 0.06 A.7A Spleen 6 0.05 0.01 6 0.01 0.002 0.17 Kidneys 7 0.28 0.0A 7 0.07 0.01. 1.16 Lungs 7 0.22 0.02 7 0.06 0.00A 0.95 Muscle 7 0.1A 0.02 7 0.0A 0.006 0.63 Femur 7 0.06 0.01 7 0.03 0.00A 0.55 Brain 7 0.55 0.05 7 0.13 0.01 2.11 Testes 2 0.30 0.23 2 0.05 0.0A 0.77 Ovaries 3 0.02 0.00A 3 0.00A 0.001 0.08 Epididymis 2 1.11 0.15 2 0.33 0.08 5.02 Urogenital A 0.13 0.03 A 0.03 0.01 0.A5 Bladder A 0.03 0.01 A 0.005 0.001 0.08 Skin 6 2.A7 0.30 7 1.03 0.12 17.31 Carcass 5 9.68 1.21 7 3.25 0.30 5A.38 Stomach 7 0.3A 0.06 7 0.06 0.01 1.03 Sm. intestine 7 0.18 0.02 7 0.03 0.01 0.5A Lg. intestine 7 0.10 0.01 7 0.01 0.003 0.2A Cecum 7 0.09 0.02 7 0.01 0.003 0.21 Gastrointestinal contents: , Stomach 7 1.25 0.A0 7 0.50 0.15 8.06 Sm. intestine 5 0.98 0.26 7 0.15 0.03 2.AA Lg. intestine 6 0.33 0.10 7 0.07 0.02, 1.15 Cecum 5 0.59 0.21 7 0.10 0.02 1.72 Totals: ' . “ Tissue 5 15.32 1.92 7 5.21 0.AA 86.6A Gastrointestinal contents 5 3.2A 1.12 7 0.82 0.20 13.36 Whole body 7 19.89 2.13 7 6.03 0.59 100.00 8'Dried for a minimum of A8 hr at 50 C. bOrgan or tissues percentage of total oven-dry weight. c . Gastrocnemius muscle only. dResidual carcass after removal of listed organs and tissues. 180 00.0 H2.0 500: mmmmsocH m0.0 mm.mH 25.O2 00.0 05.0m 05.52 mO2I2O2 H\0 0000505H H0.2 00.0 00.00 00.0 00.0H 00.00 002I202 H\0 0000505H 00.0 00.2H 00.00 22.0 20.00 02.0HH 000I000 2H\0 00005005 02.H 00.00H 00.02H 00.H 20.00 00.0mH 000I200 00\0 0000505H 00.0 00.HH 00.00 00.0 20.00 H0.20 000I200 00\0 0000505H 02.0 00.0 00.00 00.0 00.0H 00.00 2H0I0H0 0\0 0000505H 00.2 02.2 02.0H H0.0 00.0 00.00 2H0I0H0 0\0 00005005 00.0 00.0 m0.0H 00.0 00.0 02.0H 000I000 0H\m 0000505H 2H.0H H0.0 20.02 00.0H H0.0 H0.02 000I000 0\2 00005005 00.0 00.H0 00.HH m2.H 00.0 00.0 000I000 0\0 0000505H 02.0 00.0 0H.H 00.0 00.0 20.H 00HI00H 00\00\H mmmm5oeH 00.2 20.0H 20.0m 00.0 O0.m0 0O.50 02I52 0\0 0000505H 00.0 0H.0 00.02 00.0 00.2H 00.00 00I00 0H\0 0000505H H0.0 00.0 00.00 22.0 H0.0H 00.00 00I0H 0H\0 0000505H 0H.0 00.0 00.H0 00.0 2H.02 H0.00 0HI0 00\0\0 oHDom 2H o5pmm 20\mOH 5 aaOV oapmm Am\mOH 5 5500 02095: maspamo 005050 00\00 0000 0000H 00\00 0000 0000H 50 905H5 0559500 050000 0559500 905H5 0505 50 0905 .90H5 0H055 5059I0>HH 059 50 005505 05555059 0500 059 055550 00559500 0>H95o00500 505.mmmmmmww 0550580505 H0505>H05H 50 00H905 00\00 050 59H>H900OH00m .00Im 0H90B 181 00.0 00.2 5002 00005000 00.0 00.05 50.50 00.5 00.05 00.05 mmm-mmm 55\5 00005000 50.0 05.05 05.00 02.0 00.00 00.05 0001000 25\5 00005000 50.2 05.05 20.00 50.2 00.05 55.00 0001000 05\m 00005000 00.0 05.05 02.55 05.2 00.50 00.005 050-550 50\2 00005000 00.0 05.05 00.50 05.0 50.55 05.50 050-550 50\5 00005000 05.2 mm.50 00.005 20.0 50.0m oo.m05 mmmlmmm M\m 00005000 50.0 00.05 00.50 00.0 50.00 00.50 000I000 0\0 00005055 55.2 02.20 05.025 05.0 00.22 00.005 000I000 0\0 00005000 00.0 05.00 05.05 02.0 50.00 00.05 050-000 05\05\0 00005000 50.0 05.55 00.2 02.0 00.05 00.0 555-055 55\55 00005005 05.0 00.00 00.00 55.0 00.50 00.00 555-055 55\55 00005055 20.2 05.05 55.50 20.2 05.00 00.005 50100 00\05 00005000 50.0 00.05 52.05 00.0 50.25 22.20 00I00 25\05 00005005 00.0 55.00 00.555 55.5 55.00 00.005 00-00 55\05 00005000 00.2 05.05 00.00 20.0 00.05 00.00 05Im5 5\05 00005055 m2.m m0.05 55.00 m2.m 00.2 00.25 05lm5 5\OH 00005005 50.0 00.00 05.505 05.0 55.00 05.005 05-05 5\o5 00005000 00.0 2m.05 mm.m5 00.5 m0.05 00.0w 00l50 mm\m 00005005 50.0 05.55 00.055 55.0 00.50 00.005 05-55 0\0 00005055 00.0 00.0 00.0 50.0 00.0 50.5 05-05 00\m\0 05500 05 05500 50\005 x 5000 05000 50\mo5 5 5000 050050 0505500 005050 00\00 0000 00505 00\00 0000 00505 00 90555 0559500 050000 0559500 90555 0500 00 0900 .9055 05050 505930>55 059 50 005505 05555059 0800 059 055550 00559500 0>595000500 505 005005>050 0055050 5000555005 50 005005 00\00 000 5555550005000 .50Im 0500B Table B-22. 182 Accumulation and retention of 137 Cs and 0Co by Blarina brevicauda chronically ingesting lO Pinus strobus seeds per day at 22 C in the laboratory. Day N Weight Radioactivity (dpm X 103/g) Cs/Co (g :.1 s. E.) 13705 60Co Ratio Upt ake ph as e 1 u 21.08 :_ 1.55 0.29 i. 0.19 0.57 :_ 0.52 0.51 2 A 21.36 1.h5 0.82 0.6u 0.23 0.13 3.58 3 h 21.5h 1.36 1.56 1.38 0.h6 0.hh 3.h2 5 A 21.11 1.h9 5.30 1.37 1.70 0.87 3.12 8 M 21.90 1.h0 5.52 1.37 0.7M 0.30 7.h7 12 h 21.22 1.h0 5.33 1.35 0.h5 0.19 11.79 15 h 21.37 1.33 5.93 2.21 0.h1 0.16 1h.50 22 h 21.57 1.51 5.96 2.00 1.26 0.59 h.72 29 h 19.52 2.3M 8.65 3.36 1.75 0.h8 n.9u 36 h 20.1h 2.3M 9.3h h.22 0.93 0.u1 10.08 h3 h 19.90 1.95 9.38 3.50 2.32 1.11 h.0h h9 3 19.16 2.06 10.08 2.91 2.52 1.87 h.00 Retention phase 0 3 19.16 i. 2.06 10.08 :_ 2.91 2.52 1. 1.87 h.00 1 3 18.72 2.2M 7.89 2.18 0.89 0.51 8.85 2 3 19.03 1.96 5.85 1.39 0.7h 0.39 7.93 3 3 19.00 2.2h u.uu 0.88 0.6h 0.31 6.91 5 3 18.h9 2.57 2.88 0.78 0.60 0.30 u.au 8 3 18.69 2.75 1.71 0.51 0.53 0.27 3.22 15 3 17.86 2.h1 0.53 0.18 0.h0 0.16 1.3h 22 3 18.68 2.86 0.12 0.03 0.32 0.12 0.37 29 3 19.28 3.hh 0.03 0.005 0.27 0.09 0.12 36 2 20.51 h.39 0.02 0.00h 0.15 0.06 0.11 h3 2 20.05 h.76 0.012 0.005 0.1h 0.07 0.08 h9 2 19.17 h.92 0.011 0.00u 0.1h 0.06 0.08 Table B—23. 183 Caging trials to observe antagonistic behavior between Blarina brevicauda and mice in the laboratory. Trial Duration Mouse Animal Fooda Remarks (days) N Speciesb Age Dying 1 l l P.1. 25—d shrew AB No food for 7 hr. 2 1 5/6 1 P.1. 28—d mouse B No antagonism until shrew shelter (sod) placed in corner occupied by mouse. Death within h hr. 3 l/2 l P.1. 30-d mouse B Same shrew as in trial 2. Killed mouse overnight. h l/h l P.1. 8—d mouse B No antagonism until lights turned off, then shrew killed mouse within 10 min. 5 20 l P.1. Ad. None BCDE Mouse with bloody feet and tail for first few days. 6 102 2 P.1. Ad. shrew BCDE Same as trial 5 but second mouse added. Both mice with shortened tails (h cm), chewed by shrew. 7 l6 1 P.1. Ad. None BCDE No antagonism 8 16 2 P.1. Ad. shrew BCDE Same as trial 7 but second mouse added. Obesity was probable cause of death. 9 l3 5 P.1. Juv. shrew BCDE No mouse meat provided for 2 days before death. 10 12 l P.1. Ad. mouse BCDE Mouse immobilized by author, shrew killed mouse in 5 min. ll 12 2 P.1. 2l-d Ad. BCDE Mouse immobilized by author, Ad. mouse shrew killed mouse in 10 min. 12 86 l P.1. Ad. None BCDE Pregnant mouse gave birth to litter of two on day l, separated litter on day 85. Shrew and three mice nesting in same 8 X 8 X 13 cm tin can. 18h Table B—23 (cont'd) Trial Duration Mouse Animal Fooda Remarks (days) N Speciesb Age Dying 13 h l P.1. Ad. None BCE 1h 5 5 P.1. Ad. h juv. BCE Mother attacked shrew on lh-d sight, but shrew killed one Juvenile each day. 15 3 2 P.1. Ad. juv. BCE Same as trial 1A. 2l—d mouse 16 2 2 P.1. Ad. shrew BCE Same as trial 1h. Shrew very obese at death. 17 l l/2 l P.1. Ad. shrew BCD Mouse in poor health and mouse died 7 hr after shrew. 18 5 l P.1. Ad. Shrew BCD 19 2h 1 P.1. Ad. shrew BCD 20 h l P.1. Juv. mouse BC Two shrews in cage. 21 h l P.1. Ad. mouse BC Same as trial 20. 22 l/6 l M.m. Juv. mouse BCD Same as trial 20. Mouse evaded shrews until wetted with water. aFood code: A = no food; B = sunflower seed; C = laboratory chow; D = frozen laboratory mice; and E = cockroaches. bSpecies code: P.1. = Beromyscus leucopus; M.m. = Mus musculus. 185 .hmo mesa so ooamswm pom mawafis.H III om.o H mw.o mm.m m0.0 m0.0 b 00H III III III III e ma.o sm.m mo.o HH.0 a we mm.o H>.m m0.0 0H.0 m III III III III 0 m» III III III III 0 Hw.o mo.m m0.0 mH.o P Pm mw.H >m.m :H.o mm.o m om.o >m.m :o.o mH.o w 0m III III III III 0 m0.0 mm.m m0.0 :m.o N m: eH.H mm.s mo.o em.o a III III III III 6 am III III III II 0 mm. o mahm HH.0 ~m.o a. mm III III III III 0 m0.0 HH.: mm.o mm.o N am III III III III 0 mo.H ow.: >:.o w:.a N mm Pm.m w:.w 2:.m m0.0 : III III III III 0 ma III III III III 0 mm.H mm.m mm.o m:.m N ma III III III III 0 mH.H m®.m mm.H Ha.m w NH Hm.m Hm.m nm.:a om.:m m mH.H mm.m mm.H ww.w w m III III III III 0 om.H oo.w Hm.m >:.ma N m III III III III 6 mm.H me.e em.m He.aa a m III III III III 0 mm.H Fm.w mm.m mm.mm w m III .I III III I.eIII o mm.H I.mm.o mo.s I.se.am mo a mo.w + mo.®m mm.ma + :>.mm m H:.m + mw.ma om.m + mm.o: m o ooom moama z ooom hoama z Ampom coflpmomcH ozochDv camflm Aopom cofipmowsH skocxcbv zMOpopopmq gem A.m .m H.H m\moa x aaov aeeeaeoooaocm .vaowm ozp ca kHHmOfiooHpom commopp soflpwadmom ocooom mhhopwhonwa onp Opsfi camwm mzp Sonm pnwdopn coflpwadmom moo .mpoam oaofla map anm mom005mH mdomwaoaom ca 00 was mo om Nma so cohesoeom .smIm cache 186 Table B—25. Mean 137Cs/6OCo ratios for Peromyscus leucopus, Blarina brevicauda, and Tamias striatus at various times after beginning of tagged seed placement on the live-trap field plot. N for each ratio appears in Tables 11 and B-l6. Date Day Of 137Cs/6OCo Ratio Uptake P.1. B.b. T.s. 7/2h/69 0 0.20 0.21 --—a 7/26 2 h.65 0.23 0.62 8/2 9-10 1.52 10.99 _-_ 8/5 12-13 3.37 2.96 __- 8/12 19-20 3.88 ___ 1.h2 8/19 26-28 3.72 5.h7 ___ 8/26 33 7.16 7.3h ___ 9/2 ho-Al 2.71 5.92 __- 9/9 h7-h8 3.33 5.82 ___ 9/23 61—62 10.32 7.85 0.00M 10/7 75-76 3.56 A.36 __- 10/1h 82—83 h.58 5.18 ___ 10/28 96-97 3.00 h.69 ___ 11/11 110-111 1.27 1.67 ___ 11/25 12h-125 -—— 1.82 2.85 12/9 138-139 -—- 3.02 __— 1/27/70 187—188 1.51 -__ -__ 2/18 209 2.68 1.60 ——— 3/3 222-223 2.81 3.01 ___ h/T 257-258 A.72 2.66 __- h/21 271—272 n.6h 1.87 -__ 5/12 292-293 b.75 2.0h -__ 6/2 313—31h 3.A6 2.75 1.3M 6/23 338-335 1.8h __- 3,h8 7/1h 355-356 n.25 3.06 0.97 8/h 376-377 3.58 A.31 1.23 9/1 h0h-h05 2.28 2.50 1.88 Mean 3.59 3.80 1.53 aNo mammals of this species trapped during this period. 187 H.:: om.o mm.Hm m:.o :.w ma.m mm.m hm.wa mm m.»@ mm.H 2m.oz mm.o m.:H Ho.: mm.b Hw.om mm :.mm mm.H Hp.zm Hm.o w.ma :>.w m~.wa mm.Hm w» >.H~H ma.m w.oma mH.H m.mH mm.m wo.:a Fm.mw mm w.mma mm.m mm.mw Mm.a m.ma mm.: :m.ma 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Hwaflsd AU.pc00v 0NIm mHQmB 193 Table B-29. Weights of Peromyscus leuc0pus ingesting 2 Pinus strobus seeds per day in the laboratory. Means are for six mice during uptake and four mice during excretion. Day Weight (g :_1 s. E.) Winter (A.A C) Autumn (10.0 C) Spring (15.6 C) Summer (21.1 C) Uptake phase 1 21.17 :_ 0.91 21.A1 :_ 1.13 21.78 :_ 1.01 19.27 :_ 1.05 2 21.19 0.9A 22.55 1.01 21.7A 1.18 19.08 1.00 3 20.89 0.79 22.25 0.83 21.77 0.99 19.A7 1.00 5 21.52 0.89 22.53a 0.70 22.39 1.16 19.1A 1.02 8 21.3A 0.83 22.91 0.88 22.68 1.08 19.29 0.97 12 21 61 0.77 22.16b 0.81 22.80 0.99 19.71 1.03 15 21.50c 0.96 22.8A 0.98 22.33 0.82 19.62 0.99 22 22.31 0.86 22.99 0.91 22.89 0.81 19.86 0.95 29 21.93 0.96 23.0A 1.06 23.15 0.8A 20.16 1.08 36 22.70 1.0A 22.60 0.80 23.19 0.79 20.AA 1.15 A3 22.2A 0.79 23.21 1.00 23.13 0.89 20.A7 0.99 A9 22.96 1.02 23.30 1.16 23.15 0.77 20.6A 1.11 Excretion phase 0 23.07 i. 1.60 23.13 :_ 1.81 23.66 :_ 1.08 19.73 :_ 1.A3 1 22.93 1.76 22.05 1.3A 23.66 1.A1 19.31 1.26 2 22.62 1.6A 22.0A 1.36 23.50 1.28 19.23 1.30 3 22.35 1.61 21.81 1.28 23.A1 1.3A 18.77 1.15 5 22.98 1.55 22.06 1.A9 23.53 1.32 18.96 1.2A 8 22.86 1.51 21.A2 1.29 23.62 1.28 19.18 1.31 15 22.60 1.57 21.2A 1.56 23.6A 1.30 19.2A 1.30 22 22.A3 1.5A 21.A5 1.33 23.57 1.2A 18.96 1.A1 29 22.16 1.3A 21.68 1.63 23.76 1.21 19.38 1.38 36 21.7A 1.6A 21.68 1.62 23.95 1.33 19.26 1.39 A3 22.26 1.A8 21.A1 1.76 23.25 1.31 19.22 1.35 A9 21.83C 1.2A 21.10 1.A3 23.0A 1.28 18.81 1.37 57 19.A0 1.81 21.08 1.66 21.A5 1.A7 17.93 0.97 71 21.AA 1.53 21.03 1.59 21.39 1.37 18.2A 0.91 85 22.38 1.37 —-- --— 21.28 1.30 18.A3 1.11 100 22.7A 1.5A 20.A9 1.50 21.60 1.A2 18.27 1.20 8‘Day A instead of day 5. bDay 13 instead of day 12. COne animal died. dNot sampled. 19A Table B-30. Weights of Eeromyscus leucopus ingesting lO Pinus strobus seeds per day in the laboratory. Means are for six mice during uptake and four mice during excretion. Day Weight (g :.l S. E.) Winter (A.A 0) Autumn (10.0 C) Spring (15.6 0) Summer (21.1 c) Uptake phase 1 20.76 :_ 2.05 23.99 :_ 0.58 20.A6 :- 1.59 17.55 :_ 0.97 2 20.53 1.87 23.63 0.51 20.76 1.A1 17.72 0.90 3 20.52 1.83 23.06 0.8A 20.30 1.70 17.75 0.93 5 20.99 1.81 23.7Aa 0.A1 20.96 1.26 18.01 0.93 8 20.90 1.69 23.9A 0.AA 21.11 1.39 18.A8 0.9A 12 20.98 1.7A 2A.18b 0.6A 21.A7 1.32 18.A6 0.85 15 21.15 1.60 23.82 0.A9 21.16 1.28 18.83 0.85 22 21.37 1.58 2A.35 0.65 21.79 1.33 19.18 0.73 29 21.55 1.51 2A.32 0.66 21.9A 1.A1 19.27 0.79 36 21.20 1.A3 2A.87 0.78 21.75 1.35 19.A9 0.80 A3 21.52 1.36 2A.80 0.8A 21.81 1.23 19.99 0.82 A9 21.63 1.33 2A.83 0.81 21.90 1.52 19.79 0.83 Excretion phase 0 22.39 :_ 1.96 2A.16 :_ 1.08 23.32 :_ 1.92 19.19 i. 1.1A 1 22.32 2.02 23.31 0.98 22.70 1.76 18.58 1.17 2 22.16 1.89 23.27 1.0A 22.61 1.56 18.5A 1.29 3 21.9A 1.91 22.95 0.89 22.33 1.80 18.23 1.30 5 21.99 1.96 22.68 0.83 22.39 1.91 18.2A 1.35 8 21.33 1.83 22.23 0.99 22.00 2.00 18.28 1.A0 15 22.06 1.89 22.53 1.12 22.79 2.36 18.71 1.52 22 22.32 2.02 22.80 1.16 22.A7 2.1A 18.52 1.77 29 22.38 1.88 23.15 0.91 22.89 2.06 17.20 2.30 36 22.63 2.12 22.86 0.9A 23.00 1.87 19.12 1.60 A3 21.53 2.12 22.16 1.01 23.78 2.11 19.26 1.6A A9 22.16 2.00 21.90 1.33 23.58 1.95 18.52 1.6A 57 20.59 1.81 22.61C 0.82 20.97 1.38 19.29 2.22 71 20.65 1.78 22.82 0.67 20.53 1.A5 20.06 2.82 85 20.80 1.82 22.28 0.85 20.A5 1.23 21.05 3.32 100 22.65 2.23 23.21 1.09 20.A3 1.20 21.26 2.87 aDay A instead of day 5. bDay 13 instead of day 12. COne animal died. 195 Table B-31. Weights of Peromyscus leucopus ingesting 50 Pinus strobus seeds per day in the laboratory. Means are for six mice during uptake and four mice during excretion. Day Weight (g :_1 S. E.) Winter (A.A 0) Autumn (10.0 0) Spring (15.6 0) Summer (21.1 c) Uptake phase 1 23.83 i. 0.A7 22.07 :_ 1.31 21.39 :_ 1.63 18.A6 :. 1.85 2 23.57 0.39 21.60 1.38 21.05 1.60 18.55 1.7A 3 23.81 0.A2 21.93 1.36 20.59 1.A9 18.2A 1.67 5 23.67 0.39 21.91a 1.27 20.A7 1.51 18.17 1.52 8 23.7A 0.37 21.97 1.23 20.62 1.5A 18.16 1.A7 12 2A.01 0.39 21.95b 1.13 20.69 1.50 18.13 1.A3 15 23.81 0.39 21.79 1.36 20.6A 1.51 17.83 1.33 22 23.80 0.27 22.53 1.27 20.90 1.56 17.92 1.2A 29 23.65 0.37 21.62 1.16 20.72 1.58 18.69 1.A1 36 23.28 0.A0 21.51 1.17 20.79 1.56 18.88 1.60 A3 23.50 0.31 21.82 1.19 20.98 1.66 19.A0 1.58 A9 23.38 0.50 21.91 1.19 20.88 1.70 19.35 1.67 Excretion phase 0 23.87 :_ 0.35 20.63 :_ 1.37 20.99 :_ 2.A5 19.12 i. 2.16 1 2A.0A 0.31 20.60 1.61 20.51 2.62 19.13 2.15 2 23.70 0.27 20.8A 1.66 20.39 2.A9 19.17 2.26 3 23.25 0.33 20.A9 1.5A 20.06 2.53 18.97 2.30 5 23.02 0.3A 20.3A 1.66 19.83 2.A6 19.55 2.81 8 22.62 0.20 19.70 1.32 19.38 2.25 19.68 3.33 15 23.55 0.11 19.A7 1.35 19.83 2.33 19.76 3.60 22 23.75 0.31 20.37 1.09 19.71 2.13 19.00 2.83 29 23.A9 0.30 20.55 1.31 19.69 1.78 18.93 2.63 36 23.57 0.30 20.2A 1.02 20.12 1.62 19.09 2.53 A3 22.86 0.53 20.20 1.00 20.37 1.67 19.3A 2.82 A9 22.8A 0.A6 20.32 1.05 20.26 1.90 19.20 2.97 57 22.38 0.10 20.70 1.0A 19.53 1.8A 20.78 A.32 71 23.16 0.50 20.95 0.99 19.39 1.55 20.16 3.09 85 22.71 0.5A 20.32 1.27 19.860 1.86 21.76 A.89 100 23.93 0.62 19.90 1.03 19.76 1.92 19.80 2.95 3Day A instead of day 5. bDay 13 instead of day 12. cOne animal died. 196 Table B-32. Weights of Peromyscus leucopus ingesting lOO Pinus strObus seeds per day in the laboratory. Means are for six mice during uptake and four mice during excretion. Day Weight (g :.l S. E.) Winter (A.A 0) Autumn (10.0 0) Spring (15.6 0) Summer (21.1 c) Uptake phase 1 19.75 :_ 0.97 2A.65 :_ 1.67 19.36 :_ 1.09 20.86 :_ 2.08 2 19.88 0.96 2A.15 1.72 19.3A 1.13 21.37 1.90 3 19.87 0.96 23.89 1.72 19.22 1.06 20.71 2.10 5 20.0A 0.87 23.A6a 1.65 19.30 0.9A 20.29 1.96 8 19.91 0.95 23.59 1.61 19.31 0.83 20.22 2.03 12 20.A1 1.01 22.A7b 1.7A 19.51 0.71 20.A5 1.95 15 19.82 1.25 22.55 1.80 20.23 0.33 20.32 1.99 22 20.61 1.05 23.27 1.67 19.A5 0.58 20.60 2.09 29 20.57 1.0A 22.89 1.58 19.A7 0.66 21.01 2.08 36 20.78 0.96 22.71 1.63 19.A5 0.63 21.69 2.17 A3 20.77 1.10 22.99 1.73 19.A0 0.67 21.3A 2.02 A9 20.95 1.10 22.57 1.5A 19.5A 0.78 21.A0 2.06 Excretion phase 0 20.95 :_ 1.61 20.99 :_ 1.82 20.05 :. 0.A3 21.33 :_ 3.26 1 20.92 1.5A 20.28 1.8A 19.78 0.A3 21.77 3.33 2 20.33 1.56 20.53 1.79 19.78 0.A8 21.72 3.A5 3 19.89 1.58 20.82 2.0A 19.52 0.50 21.7A 3.51 5 20.39 1.61 20.17 2.03 19.32 0.35 21.79 3.69 8 20.17 1.63 20.60 1.A9 18.86 0.35 21.70 3.83 15 20.A2 1.67 22.16 1.72 18.90 0.31 21.22 2.91 22 19.86 1.63 20.98 1.81 19.89 0.30 20.69 2.57 29 19.96 1.65 21.89 1.66 20.56 0.30 21.05 2.50 36 19.68 1.63 21.26 1.23 20.A8 0.22 20.92 2.69 A3 19.39 1.55 20.90 1.21 20.01 0.65 20.68 2.A8 A9 19.71 1.63 21.08 1.A8 19.76 0.72 20.8A 2.A7 57 19.06 1.65 20.96 1.69 19.15 0.7A 20.56 2.87 71 20.13 1.A2 20.61 1.66 19.60 0.78 21.22 3.13 85 20.86 1.79 20.98 1.33 19.77 0.75 21.23 3.01 100 19.51 1.62 20.88 1.A9 19.5A 0.A5 19.19 2.70 aDay h instead of day 5. bDay 13 instead of day 12. 197 Table B—33. Body burden of 13705 in Peromyscus leucopus ingesting 2 Pinus strobus seeds per day in the laboratory. Means are for Six mice during uptake and four mice during excretion. Day 137CS Radioactivity (dpm X l03/g :_l S. E.) Winter (A.A C) Autumn (10.0 C) Spring (15.6 C) Summer (21.1 c) Upt ake phase 1 0.27 :_ 0.0A 0.31 :_ 0.07 0.18 + 0.07 0.32 :_ 0.02 2 0.A0 0.05 0.50 0.0A 0.AA 0.06 0.51 0.03 3 0.A9 0.06 0.58 0.06 0.51 0.05 0.61 0.03 5 0.61 0.07 0.698 0.05 0.60 0.05 0.81 0.07 8 0.61 0.0A 0.75 0.06 0.72 0.08 0.91 0.10 12 0.62 0.02 0.83b 0.10 0.72 0.05 1.10 0.05 15 0.68 0.10 0.8A 0.10 0.79 0.07 1.10 0.08 22 0.66C 0.06 0.86 0.0A 0.75 0.03 1.09 0.09 29 0.7A 0.06 0.82 0.07 0.77 0.06 1.12 0.13 36 0.73 0.08 0.85 0.07 0.81 0.10 1.21 0.13 A3 0.70 0.05 0.88 0.07 0.7A 0.05 1.62 0.30 A9 0.6A 0.07 0.96 0.1A 0.83 0.07 1.35 0.10 Excretion phase 0 0.67 :_ 0.10 1.08 :_ 0.16 0.91 :_ 0.08 1.3A :_ 0.16 1 0.A9 0.09 0.82 0.12 0.66 0.05 1.02 0.15 2 0.36 0.07 0.6A 0.10 0.52 0.0A 0.79 0.15 3 0.28 0.06 0.52 0.09 0.A1 0.03 0.6A 0.13 5 0.17 0.0A 0.3A 0.07 0.28 0.03 0.39 0.08 8 0.09 0.02 0.20 0.0A 0.16 0.02 0.20 0.0A 15 0.03 0.01 0.08 0.01 0.05 0.007 0.05 0.01A 22 0.02 0.00A 0.03 0.006 0.02 0.003 0.03 0.005 29 0.012 0.002 0.027 0.003 0.01A 0.002 0.017 0.003 36 0.011 0.002 0.016 0.002 0.011 0.001 0.011 0.002 A3 0.007 0.001 0 013 0.002 0.008 0.001 0.009 0.002 A9 0.00Ac 0.001 0.012 0.003 0.006 0.001 0.011 0.002 57 0.002 0.0005 0.006 0.002 0.00A 0.001 0.006 0.001 71 0.002 0.0005 0.00A 0.001 0.003 0.0003 0.005 0.001 85 0.002 0.000A ---d --- 0.003 0.0003 0.00A 0.0002 100 0.001 0.0001 0.002 0.001 0.002 0.0003 0.003 0.0003 aDay A instead of day 5. Day 13 instead of day 12. b cOne animal died. dNot sampled. 198 Table B-3h. Body burden of 137CS in Peromyscus leucopus ingesting lO Pinus strobus seeds per day in the laboratory. Means are for six mice during uptake and four mice during excretion. Day 1370s Radioactivity (dpm X 103/g :_1 S. E.) Winter (A.A 0) Autumn (10.0 0) Spring (15.6 0) Summer (21.1 c) Uptake phase 1 1.35 + 0.22 1.2A :_ 0.16 1.7A :_ 0.16 1.66 :_ 0.17 2 2.07 0.20 1.99 0.17 2.7A 0.1A 2.57 0.22 3 2.A8 0.25 2.6A 0.35 3.A0 0.33 3.10 0.35 5 2.95 0.2A 2.86a 0.37 3.99 0.28 3.70 0.A5 8 3.11 0.20 3.26 0.5A A.16 0.31 A.52 0.37 12 3.33 0.26 3.52b 0.A6 A.65 0.22 A.91 0.A7 15 3.38 0.33 3.51 0.A5 A.78 0.17 A.A0 0.A9 22 3.6A 0.32 3.87 0.A0 A.67 0.21 A.79 0.56 29 3.53 0.38 3.73 0.35 A.30 0.19 5.12 0.53 36 A.08 0.33 A.17 0.39 A.32 0.13 5.22 0.68 A3 3.A5 0.26 A.00 0.A1 A.A3 0.07 A.A6 0.57 A9 3.85 0.A2 A.58 0.66 A.21 0.12 5.05 0.67 Excretion phase 0 3.95 :_ 0.6A 5.19 :_ 0.8A A.30 :_ 0.13 5.16 :_ 0.85 1 2.86 0.56 3.88 0.7A 3.35 0.17 A.05 0.82 2 2.06 0.A2 3.03 0.72 2.6A 0.12 3.51 0.81 3 1.61 0.38 2.A7 0.60 2.18 0.16 2.9A 0.73 5 0.99 0.26 1.A9 0.A0 1.A2 0.12 2.A0 0.66 8 0.53 0.1A 0.90 0.28 0.80 0.10 1.A6 0.A0 15 0.17 0.0A 0.25 0.08 0.26 0.02 0.51 0.17 22 0.08 0.01A 0.11 0.03 0.12 0.005 0.20 0.07 29 0.06 0.006 0.07 0.011 0.06 0.007 0.18 0.07 36 0.0A 0.00A 0.0A 0.007 0.05 0.007 0.08 0.02 A3 0.06 0.012 0.0A 0.006 0.0A 0.006 0.06 0.013 A9 0.03 0.006 0.0A 0.007 0.03 0.006 0.06 0.013 57 0.02 0.002 0.025C 0.005 0.026 0.00A 0.03 0.007 71 0.015 0.003 0.018 0.007 0.020 0.00A 0.02A 0.006 85 0.013 0.002 0.015 0.007 0.016 0.00A 0.018 0.00A 100 0.010 0.002 0.012 0.006 0.015 0.003 0.015 0.005 aDay h instead of day 5. bDay 13 instead of day 12. COne animal died. Table B-35. Body burden of 137 199 CS in Peromyscus leuc0pus ingesting 50 Pinus strobus seeds per day in the laboratory. Means are for six mice during uptake and four mice during excretion. Day 137Cs Radioactivity (dpm X 103/g :_l S. E.) Winter (A.A 0) Autumn (10.0 C) Spring (15.6 0) Summer (21.1 c) Uptake phase 1 6.08 :_ 0.A3 A.A0 :_ 0.70 8.33 :_ 0.80 10.75 :_ 1.20 2 10.30 0.AA 8.79 0.75 10.56 2.19 16.35 1.80 3 12.A6 0.62 12.55 1.30 16.65 0.68 19.78 1.66 5 15.68 1.26 13.98a 1.56 21.9A 0.93 25.75 2.A8 8 16.88 1.08 18.A8 2.27 23.71 1.12 28.52 2.8A 12 17.70 1.22 20.0Ab 2.7A 25.67 1.32 30.A3 2.70 15 17.55 1.36 22.66 3.38 27.05 1.69 31.A1 2.50 22 18.32 1.A1 20.21 2.79 27.31 2.75 31.31 2.38 29 19.01 1.13 22.28 2.57 29.86 2.55 30.91 1.85 36 22.AA 1.75 2A.7A 3.99 29.60 3.25 37.1A A.68 A3 19.59 1.27 22.37 2.53 29.02 2.6A 31.AA 2.A2 A9 20.03 1.5A 25.3A 2.77 28.72 2.39 31.95 1.58 Excretion phase 0 20.AA :_ 2.20 27.85 :_ 3.59 28.A3 :_ 2.69 31.71 1.30 1 1A.A3 1.73 20.56 3.5A 23.A2 2.93 25.25 2.11 2 11.AA 1.33 15.86 3.30 19.38 2.63 20.9A 2.07 3 9.21 1.18 1A.02 3.31 16.92 2.65 18.50 1.91 5 6.07 0.82 9.12 2.20 12.09 1.98 1A.21 1.85 8 3.39 0.53 5.92 1.59 7.16 1.05 8.60 1.A5 15 1.05 0.15 2.06 0.77 2.97 0.62 3.A8 0.36 22 0.AA 0.05 0.88 0.38 1.35 0.30 1.50 0.21 29 0.28 0.025 0.57 0.21 0.70 0.18 0.86 0.08 36 0.21 0.020 0.29 0.10 0.A8 0.15 0.50 0.05 A3 0.2A 0.019 0.30 0.12 0.3A 0.10 0.37 0.06 A9 0.15 0.010 0.22 0.06 0.29 0.09 0.29 0.05 57 0.08 0.005 0.08 0.02 0.15 0.03 0.17 0.02 71 0.06 0.003 0.05 0.011 0.08 0.007 0.11 0.015 85 0.05 0.005 0.0A 0.007 0.07c 0.00A 0.09 0.015 100 0.0A 0.002 0.03 0.003 0.06 0.006 0.07 0.010 aDay h instead of day 5. b Day 13 instead of day 12. COne animal died. 200 Table B—36. Body burden of 137Cs in Peromyscus leucopus ingesting 100 Pinus strobus seeds per day in the laboratory. Means are for six mice during uptake and four mice during excretion. Day 137CS Radioactivity (dpm X 103/g i_l S. E.) Winter (A.A C) Autumn (10.0 C) Spring (15.6 C) Summer (2l.l C) Uptake phase 1 15.16 :_ 1.17 13.59 :_ 1.A0 17.78 :_ 1.A2 18.97 :_ 1.71 2 2A.6A 2.11 18.68 1.81 29.30 2.67 31.8A 2.72 3 31.71 2.88 23.17 2.89 38.51 3.28 A1.97 3.50 5 36.55 A.11 28.5Aa A.15 A7.26 2.10 57.0A A.30 8 37.70 A.66 3A.69 5.20 53.72 2.50 70.00 A.83 12 A0.08 5.15 A0.A8b 6.30 57.29 3.09 71.26 A.58 15 A1.38 5.59 A8.10 8.1A 58.09 3.33 75.33 3.69 22 A2.78 A.30 A6.92 7.51 62.7A A.8A 75.1A 5.A7 29 A7.75 7.03 50.98 7.1A 62.10 A.10 69.92 5.03 36 A3.15 5.A3 50.26 6.78 61.78 3.86 70.19 A.67 A3 AA.06 6.27 53.09 9.72 60.66 2.63 75.93 A.A3 A9 51.52 7.80 53.38 9.35 60.35 2.67 7A.28 5.61 Excretion phase 0 59.09 :_ 9.68 59.A6 :_13.21 61.6A :_ 2.82 75.16 :_ 5.68 1 A3.6A 7.19 AA.15 10.A9 A6.85 2.A7 59.18 A.A3 2 35.05 6.0A 35.A5 8.9A 39.62 2.73 50.3A 3.73 3 28.18 5.A3 26.86 7.19 32.78 2.22 A2.A0 2.28 5 17.72 3.61 18.A8 5.A0 23.33 1.65 31.9A 2.88 8 9.06 1.99 8.3A 2.63 1A.A6 1.26 20.81 1.58 15 2.72 0.63 2.26 1.00 A.55 0.A5 8.11 1.37 22 1.27 0.38 0.78 0.30 1.85 0.A6 3.A6 0.76 29 0.69 0.16 0.66 0.18 1.03 0.36 1.50 0.32 36 0.69 0.15 0.39 0.09 0.68 0.23 0.87 0.16 A3 0.37 0.06 0.32 0.06 0.52 0.16 0.60 0.10 A9 0.33 0.0A 0.A0 0.08 0.A5 0.13 0.A7 0.06 57 0.18 0.02 0.16 0.03 0.30 0.07 0.3A 0.03 71 0.11 0.012 0.09 0.016 0.20 0.05 0.2A 0.02 85 0.08 0.009 0.07 0.015 0.16 0.05 0.19 0.02 100 0.07 0.011 0.06 0.012 0.13 0.0A 0.20 (LOT aDay h instead of day 5. bDay l3 instead of day 12. Table B-37. Body burden of 60 201 Co in Peromyscus leucopus ingesting 2 Pinus strObus seeds per day in the laboratory. Means are for six mice during uptake and four mice during excretion. Day 60 Co Radioactivity (dpm X 103/g :_l S. E.) Winter (A.A C) Autumn (10.0 0) Spring (15.6 C) Summer (21.1 C) Uptake phase 1 0.A3 :_ 0.1A 0.21 0.0A 0.15 :_ 0.05 0.19 i. 0.05 2 0.A7 0.11 0.20 0.03 0.33 0.09 0.36 0.09 3 0.A2 0.11 0.27 0.06 0.A1 0.09 0.36 0.08 5 0.A2 0.07 0.25a 0.05 0.37 0.09 0.32 0.06 8 0.55 0.22 0.A6 0.15 0.30 0.0A 0.63 0.22 12 0.36 0.08 0.28b 0.02 0.28 0.03 0.A1 0.11 15 0.A1 0.07 0.35 0.0A 0.32 0.0A 0.A3 0.03 22 0.50C 0.05 0.A5 0.08 0.3A 0.07 0.A9 0.06 29 (L59 0.08 0.A3 0.07 0.28 0.03 0.32 0.05 36 0.57 0.10 0.38 0.06 0.A1 0.09 1.58 1.06 A3 0.A8 0.09 0.90 0.21 0.37 0.02 0.70 0.2A A9 0.52 0.07 0.AA 0.06 0.A1 0.10 0.A0 0.06 Excretion phase 0 0.AA 0.02 0.50 0.08 0.A5 :_ 0.16 0.A7 0.05 1 0.13 0.006 0.19 0.025 0.13 0.03 0.13 0.008 2 0.08 0.007 (L11 0.01A 0.07 0.013 0.08 0.011 3 0.06 0.007 0.08 0.01A 0.06 0.0M) 0.07 0.013 5 0.05 0.007 0.06 0.009 0.05 0.007 0.06 0.0M) 8 0.0A 0.007 0.06 0.009 0.0A 0.005 0.05 0.009 15 0.032 0.00A 0.0A6 0.007 0.031 0.00A 0.032 0.008 22 0.026 0.00A 0.036 0.005 0.025 0.00A 0.03A 0.007 29 0.023 0.003 0.032 0.00A 0.022 0.002 0.028 0.006 36 0.021 0.003 0.029 0.003 0.020 0.002 0.026 0.006 A3 0.018 0.002 0.025 0.003 0.018 0.002 0.023 0.005 A9 0.0110 0.002 0.026 0.003 0.018 0.002 0.02A 0.005 57 0.019 0.002 0.023 0.003 0.017 0.002 0.02A 0.005 71 0.013 0.002 0.021 0.002 0.017 0.002 0.020 0.00A 85 0.012 0.002 ---d --- 0.01A 0.001 0.018 0.003 100 0.012 0.002 0 019 0.003 0.012 0.001 0.019 0.00A aDay h instead of day 5. Day 13 instead of day 12. b COne animal died. dNot sampled. Table B-38. Body burden of 60 202 C0 in Peromyscus leucopus ingesting lO Pinus strobus seeds per day in the laboratory. Means are for six mice during uptake and four mice during excretion. Day 60 Co Radioactivity (dpm x 103/g 1.1 S. E.) Winter (A.A C) Autumn (10.0 C) Spring (15.6 C) Summer (21.1 C) Uptake phase 1 2.82 :_ 1.18 1.3A :_ 0.33 2.AA :_ 0.51 2.52 i. 0.39 2 2.82 0.5A 1.85 0.30 1.76 0.21 3.05 0.27 3 3.A9 0.61 3.57 0.87 1.96 0.22 2.A0 0.38 5 3.06 0.A2 2.20a 0.67 2.57 0.36 3.13 0.59 8 3.79 0.68 1.51 0.28 3.68 0.81 A.13 0.75 12 3.10 0.37 2.66b 0.50 2.86 0.2A 3.88 1.03 15 2.AA 0.31 1.76 0.37 2.A9 0.32 2.52 0.A3 22 2.73 0.30 1.88 0.29 3.08 0.55 2.A3 0.25 29 3.28 0.77 2.26 0.2A 2.A0 0.36 2.56 0.28 36 2.35 0.30 2.16 0.36 3.10 0.63 3.10 0.32 A3 2.68 0.2A 2.12 0.33 2.7A 0.29 2.AA 0.27 A9 2.57 0.32 3.63 0.85 3.22 0.A0 2.75 0.A2 Excretion phase 0 2.A3 :_ 0.39 A.A7 :_ 1.03 2.89 :_ 0.50 3.09 :_ 0.56 1 0.72 0.13 1.3A 0.28 0.82 0.11 0.76 0.07 2 0.A2 0.08 0.66 0.12 0.51 0.09 0.A1 0.03 3 0.3A 0.06 0.AA 0.07 0.A3 0.09 0.33 0.03 5 0.28 0.05 0.33 0.05 0.38 0.09 0.31 0.0A 8 0.2A 0.0A 0.28 0.0A 0.32 0.08 0.2A 0.03 15 0.18 0.03 0.23 0.0A 0.26 0.07 0.18 0.021 22 0.13 0.025 0.18 0.03 0.21 0.05 0.15 0.020 29 0.12 0.02A 0.16 0.02 0.18 0.0A 0.1A 0.016 36 0.10 0.021 0.13 0.012 0.15 0.036 0.11 0.015 A3 0.10 0.021 0.12 0.013 0.1A 0.033 0.09 0.009 A9 0.08 0.017 0.12 0.016 0.12 0.027 0.10 0.01A 57 0.08 0.015 0.10C 0.010 0.13 0.03A 0.08 0.013 71. 0.06 0.015 0.09 0.008 0.12 cu03A 0.07 0.012 85 0.06 0.01A 0.09 0.007 0.10 0.033 0.07 0.013 100 0.05 0.011 0.07 0.006 0.09 0.030 0.06 0.011 aDay h instead of day 5. Day 13 instead of day 12. b COne animal died. 203 Table B-39. Body burden of 60Co in Peromyscus leucgpus ingesting 50 Pinus strobus seeds per day in the laboratory. Means are for six mice during uptake and four mice during excretion. Day 6OC0 Radioactivity (dpm X 103/g :_l S. E.) Winter (A.A 0) Autumn (10.0 0) Spring (15.6 0) Summer (21.1 c) Uptake phase 1 13.A9 :_ 1.A5 7.A3 :_ 1.55 16.10 :_ 3.56 27.A2 :_ 5.65 2 17.26 2.79 1A.03 0.37 16.58 1.99 18.05 2.90 3 17.89 1.A3 18.57 1.79 1A.A7 1.86 17.39 2.A5 5 15.79 1.07 12.97a 0.80 15.69 1.52 18.61 2.9A 8 1A.15 1.53 1A.15 1.66 17.03 2.16 17.75 2.85 12 1A.5A 1.50 13.77b 1.37 17.53 2.A3 18.39 3.32 15 15.16 1.61 15.A1 1.12 16.A3 1.A2 22.38 A.66 22 1A.36 1.A5 1A.82 2.27 15.57 1.92 21.1A 3.50 29 13.61 0.83 18.63 2.9A 20.32 2.78 18.9A 3.00 36 16.A3 1.63 17.05 1.81 19.8A 2.A6 3A.5A 1A.62 A3 16.AA 1.23 19.1A 1.A6 18.65 1.78 19.72 3.2A A9 17.18 0.97 23.25 2.69 20.12 2.85 18.6A 2.A8 Excretion phase 0 17.07 :- 1.A9 2A.06 :_ 3.23 21.21 :_ A.31 20.58 :_ 2.78 1 5.02 0.67 6.6A 1.03 A.63 0.7A 3.09 0.69 2 2.A9 0.26 3.20 0.A2 1.98 0.25 2.10 0.A3 3 1.83 0.21 2.20 0.33 1.57 0.26 1.90 0.37 5 1.A8 0.18 1.6A 0.29 1.31 0.23 1.92 0.5A 8 1.25 0.1A 1.25 0.18 1.05 0.17 1.53 0.38 15 0.92 0.11 0.96 0.1A 0.88 0.18 1.15 0.2A 22 0.76 0.08 0.76 0.10 0.72 0.1A 0.93 0.18 29 0.65 0.07 0.68 0.10 0.62 0.11 0.86 0.1A 36 0.58 0.06 0.58 0.08 0.55 0.09 0.72 0.12 A3 0.50 0.0A 0.56 0.08 0.A8 0.08 0.66 0.12 A9 0.A6 0.05 0.50 0.05 0.A2 0.05 0.62 0.11 57 0.A2 0.05 0.A3 0.05 0.A0 0.05 0.5A 0.12 71 0.3A 0.0A 0.37 0.05 0.32 0.02 0.A2 0.06 85 0.31 0.0A 0.35 0.05 0.31C 0.02 0.A0 0.07 100 0.26 0.03 0.31 0.0A 0.28 0.01 0.37 0.06 aDay h instead of day 5. bDay 13 instead of day 12. COne animal died. 20h Table B-AO. Body burden of 60Co in Peromyscus leucopus ingesting 100 Pinus strobus seeds per day in the laboratory. Means are for six mice during uptake and four mice during excretion. Day 60Co Radioactivity (dpm x 103/g :_1 S. E.) Winter (A.A 0) Autumn (10.0 0) Spring (15.6 0) Summer (21.1 c) Uptake phase 1 32.07 :_ 3.83 32.0A :_ 3.A8 A3.00 :- 7.2A 5A.20 :_ 9.19 2 55.70 3.A6 33.99 6.A9 53.8A 6.79 50.20 7.08 3 52.50 A.82 28.71 5.91 51.75 6.05 A9.A9 8.63 5 56.21 5.21 37.11a 5.26 A3.76 5.55 6A.18 10.58 8 A9.98 6.56 A5.31 5.36 A5.A9 5.85 57.10 7.22 12 A6.61 3.88 AA.95b 8.A1 A7.00 A.A7 52.68 8.92 15 A3.79 A.12 61.37 21.09 58.1A 6.58 56 29 5.18 22 A9.37 5.36 50.30 9.10 60.00 6.60 72.03 1A.91 29 A7.A8 6.92 68.16 18.19 67.61 6.08 62.25 11.59 36 A5.92 3.80 57.6A 11.75 58.52 5.56 53.A3 10.52 A3 5A.06 A.A6 72.65 15.05 58.08 6.66 6A.31 12.17 A9 61.30 9.1A 68.32 13.87 5A.18 A.03 50.92 5 A5 Excretion phase 0 67.29 :_12.65 76.83 :_20.21 52.36 :_ 5.99 51.96 :_ 7.5A 1 12.A0 A.12 27.27 11.35 12.15 2.71 1A.27 5.A1 2 5.72 1.37 1A.12 6.15 6.72 1.3A 7.99 2.3A 3 A.23 0.82 8.70 3.80 5.10 0.91 6.23 1.60 5 3.60 0.75 6.26 2.73 A.29 0.65 A.88 1.01 8 2.98 0.50 3.66 0.85 3.8A 0.56 A.12 0.86 15 2.21 0.A2 2.68 0.55 2.98 0.53 3.26 0.59 22 1.89 0.37 2.37 0.A3 2.29 0.37 2.83 0.A8 29 1.61 0.32 1.99 0.AA 1.97 0.30 2.39 0.A2 36 1.A1 0.28 1.79 0.3A 1.72 0.28 2.23 0.A1 A3 1.30 0.25 1.58 0.31 1.63 0.30 2.00 0.3A A9 1.1A 0.18 1.A8 0.28 1.53 0.29 1.78 0.30 57 1.05 0.17 1.30 0.30 1.AA 0.30 1.72 0.32 71 0.86 0.1A 1.12 0.27 1.2A 0.27 1.A9 0.29 85 0.76 0.13 0.95 0.21 0.76 0.23 1.32 0.26 100 0.71 0.09 0.8A 0.18 0.96 0.18 1.32 0.25 8'Day A instead of day 5. bDay 13 instead of day 12. Table B-Al. List of scientific and common names for plants mentioned in the text.a Scientific Name Common Name Acer rubrum Acer saccharum Carya glabra Carya ovata Carya tomentosa Cercis canadensis Cornus florida Crataegus spp. Diospyros virginiana Fraxinus americana Juglans nigra Liquidambar styraciflua Liriodendron tulipifera Morus rubra Nyssa sylvatica Ostrya virginiana Oxydendrum arboreum Pinus echinata Pinus monticola Pinus strObus Prunus serotina Quercus alba Quercus falcata Quercus prinus Quercus stellata Quercus velutina Rhamnus caroliniana Sassafras albidum Ulmus americana Ulmus thomasii Viburnum lentago Vitis spp. Red maple Sugar maple Pignut hickory Shagbark hickory Mockernut hickory Eastern redbud Dogwood Crabapple Persimmon White ash Black walnut Sweet gum Yellow poplar Red mulberry Black gum Hophornbeam Sourwood Shortleaf pine Western white pine Eastern white pine Black cherry White oak Southern red oak Chestnut oak Post oak Black oak Carolina buckthorn Sassafras American elm Rock elm Nannyberry Wild grape aFrom Little, E. L. Jr. Checklist of Native and Naturalized Trees of the United States. U.S.D.A., Forest Service, Agr. Handbook A1, A72 pp. Table B-A2. List of scientific and common names for vertebrates listed in the text. Scientific Name Common Name Blarina brevicauda Glauc omys volans Microtus pinetorum Peromyscus leucopus Peromyscus nuttalli Sciurus carolinensis Sorex longirostris Tamias striatus Corvus brachyrhynchos Thryothorus ludovicianus Sceloporus undulatus Terrapene carolina Bufo americanus Mammalsa Short-tailed shrew Southern flying squirrel Pine vole White-footed mouse Golden mouse Gray squirrel Southeastern shrew Eastern chipmunk Birds Crow Carolina wren Reptiles Fence lizard Eastern box turtle Amphibians American toad aFrom Hall, E. R. and K. R. Kelson. 1959. The Mammals of North America. Ronald Press, New York, 1,083 PP. bGeneric name of Ochrotomys also accepted. X. APPENDIX C Multichannel Analyzer System X. APPENDIX C To assist future studies using a multichannel analyzer system (Fig. C-l), a description of some of the potential errors is desirable. The procedures are applicable to samples containing two or more radio- isotopes. The desirability of using two distinct radioisotopes was emphasized in this study where the ratio between two radioisotopes (Cs/Co ratio) was used to determine the day of excretion for mice trapped on the field plot. A single-isotope study would not have allowed correlation to the field study. Unknown samples were counted for variable lengths of time, at- tempting to Obtain total counts in the maximum channel (normally 0.66 Mev, the 137Cs peak channel) of between 25,000 and the maximum of 99,999 counts. The counts in each channel were punched on paper tape and subsequently analyzed by a least squares regression program (Brooks _e_t_ 21;, 1970). The counting geometry was critical with this system, due to a very low counting efficiency. For the crystal used to count animals, the efficiency in the maximum channel was approximately 1% of the total dpm. Lateral or vertical movements by the animals during counting were undesirable, and a set of containers (described in Methods and Materials) were used to restrict movement as much as possible without harming the animal (Fig. C-2). Mice and shrews with- stood the restrictions of this small vial satisfactorily. 207 208 "P VIII YYYVVV (VVI .npmoshwcqs mep $.70me up.» £0250 093 .8000 M33 . 80m 005305» Hmcnmnofipasz 0.80300 213 ma ohm: 05p “”26.Hmwawsmmnwflaswrwmomahwqmww so.“ a E: ofimeOpdm Gm ma 3:: mac . . . . cammmewmm MOMwawow pmppacb .mpnmamhdmoms zpfifipowogwh HO.H 005:8 €080“:me En : .: 'III.I .A Iu\.II .HIo magmas 209 a 7 Figure C—2. Container used to control geometry of small mammals during radioactivity determinations. Container is on top of the NaI crystal and is contained within a copper-sheathed lead shield. White-footed mouse is in container. 210 To reduce the potential error due to count rates of less than 20,000 dpm, the time each sample was counted was increased from 5 min. up to a maximum of 20 min./samp1e. The most serious error appeared to be an inherent amount of changing sensitivity within the analyzer. A slight change in the voltage resulted in the 137 Cs peak drifting from one channel to an adjacent channel while a series of samples were being counted. The analyzer was maintained on a voltage-regulated source of power, but this was not sufficient to prevent this error from appearing. In a test case, the amplification of the input signals was purposefully 137 varied to create shifting locations of the Cs peak, and the out- 137 put was subsequently analyzed by comparison to a single Cs standard, whose peak occurred in channel 65 (Fig. C-3). A shift of one complete channel, between the standard and the unknown sample, created an error of 8% in estimating the radioactivity of the unknown sample; a two channel Shift resulted in up to a 16% error. Although a 10% or greater error is accepted by some investigators, there does appear to be a solution to this problem of shifting channels, if refined estimates are desired. The RESAP program (Brooks gt a1), 1970) computed the concentration of the radioisotope and a standard deviation of the concentration regard- less of Where the peak of the unknown occurred. A coefficient of varia- tion is calculated and printed with the output for each sample. If the predicted radioactivity is correlated to the coefficient of variation, a typical bell-shaped curve can be produced (Fig. C-A). If a mathe- matical expression of this correlation could be built into the computer 211 (x103) /\\ // 60C0 160 / \ COMPUTED 600o RADIOACTIVITY (dpm) 120 r \ 100 \. (x103) 50 1/\\ 40 \ .0 / \ / \ 20 \ 10 COMPUTED 137Cs RADIOACTIVITY (dpm) 60 62 64 66 68 70 72 CHANNEL WITH ‘37Cs PEAK IN UNKNOWN SAMPLE Figure C-3. Influence of channel drift of the 137Cs peak upon computed radioactivity in the same sample using the RESAP analysis. 212 .mwmzfimqm m Mo pcmfiowmmmoo wmpsaaoo 03p op hpfi>fipomOH00p mopma wmpsmEoo map mo :oflpmamnpoo 207—.040... 0.0 0.0 Nd to O IIIIIIILII liar o/i .IIIIO Int/Ill O III/T / / OI. /. OIIIII. /0l .sIo magmaa 0* ON 00 00 C) In (Ludp) All/\llOVOIGVH 031000100 931.9 ”A $2 X 213 analysis, a much more SOphisticated and accurate analysis might occur. The correlation, however, differs for each radioisotope counted, and 137 appears to differ for varying concentrations of Cs. Thus, the logical correction of this error would be the employment of a gain- Shift correction (already used in a portion of the computer program) to shift the spectrum of the unknown sample until the isotopic peak is coincident with the standard for that isotope, and then calculate the radioactivity. The present gain-shift corrects only once and assumes that the remaining samples have the same error as the first. XI. VITA John Beatty Mathies Candidate for the Degree of Doctor of Philosophy Final Examination: May 26, 1971 Dissertation: Annual consumption of cesiumrlBT and cobalt-60 labeled seeds by small mammals in an oakéhickory forest Major Subject: Forest Ecology Minor subject: Biometrics Biographical Items: Born August 2, 1939 in Seattle, Washington Undergraduate Forest Management, University of Studies: Washington, B. S. Degree: 1962 Graduate Forest Ecology, Michigan State Studies: University, M. S. Degree: 1967 Title: Influence of the eastern cottontail on tree reproduction in sugar maple- beech stands of southern Michigan Experience: Forestry Aid, U.S.F.S., 1960 Forestry Technician, U.S.F.S., 1961 Forester, U.S.F.S., 1962-1965 Graduate Teaching Assistant, Michigan State University, 1965-1968 Graduate Fellow, Oak Ridge Associated Universities, 1968-1971 Member: Society of American Foresters Xi Sigma Pi Ecological Society of America American Institute of Biological Sciences 21A