BRARIES ”(MN 3 cmcm s W lllllllll 2”! Will 31 This is to certify that the thesis entitled A COMPARISON OF ACRONEURIA LYCORIAS (PLECOPTERA) PRODUCTION AND GROWTH RATES IN NORTHERN MICHIGAN HARD AND SOFT WATER STREAMS presented by Susan L. Eggert has been accepted towards fulfillment of the requirements for M.S. degrppin Fisheries & Wildlife Major professor Date M 07539 MS U is an Affirmative Action/Equal Opportunity Institution A COMPARISON OF ACBQNEHBIA LXQQRIAS (PLECOPTERA) PRODUCTION AND GROWTH RATES IN NORTHERN MICHIGAN HARD AND SOFT WATER STREAMS BY Susan L. Eggert A THESIS Submitted to Michigan State University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE Department of Fisheries and Wildlife 1992 Z? 0 1’ .. 5 (7/ ABSTRACT A COMPARISON OF AQBQNEHBIA LXQQBIAS (PLECOPTERA) PRODUCTION AND GROWTH RATES IN NORTHERN MICHIGAN HARD AND SOFT WATER STREAMS BY Susan L. Eggert Annual production and growth rates of Acrgnenria lxanrias, a predaceous stonefly, were compared between fourth-order hard and soft water streams in Michigan's upper pennisula from 1988 to 1990. Mean annual production of A. lyggrias, calculated using the size frequency method, was 5.0 times greater at the hard water site. Mean standing crop biomass was estimated from monthly Hess samples, and was 4.9 times greater at the hard water site. Annual P/B ratios were similar between sites. Monthly growth rates of nymphs living in the streams were calculated from changes in mean weight of cohorts. Growth rates of nymphs were similar at each site for comparable age classes and sexes. Individual growth rates of nymphs reared in the laboratory at high and low water hardnesses with unlimited food and space were not significantly different. Low A. lyngrias production estimates at the soft water site resulted from physical, biological or habitat constraints on standing crop biomass, rather than slower growth rates due to low water hardness. Dedicated to the memory of Dr. Willard L. Gross ACKNOWLEDGMENTS I offer my sincere appreciation to Dr. Thomas M. Burton for his suggesting and supervising this study, and for his patience during the writing of this thesis. Special thanks go to the members of my committee, Dr. Darrell L. King and Dr. Richard W. Merritt, for their helpful discussions, comments, and suggestions. I thank Dr. Charles E. Cress and Dr. William E. Cooper for their advice on statistical analyses. Dr. William L. Hilsenhoff of the University of Wisconsin-Madison confirmed the identification of A. lycorias specimens collected in this study. I also wish to thank my fellow graduate students and Dr. Jean Stout for their comments and advice regarding this work. I especially would like to acknowledge the help of Dr. Dennis Mullen, and Dr. Burton in the field. Without their assistance, the winter sampling would have been impossible. Support for this research was provided in part by the Naval Electronic Systems Command through a subcontract to IIT Research Institute under contract number NOOO39~88~0065. Other funding was provided by a Grant-in-Aid of Research from Sigma Xi and the Theodore Roosevelt Memorial Fund of The American Museum of Natural History. iv n- -‘«'---'--'~'-M-‘-.I"ax .1. ‘ ‘ 2:.1‘ ‘ * 2: ' n ; ... TABLE OF CONTENTS Page LIST OF TABLES . . . . . . . . . . . . . . vii LIST OF FIGURES . . . . . . . . . . . . . x INTRODUCTION . . . . . . . . . . . . . . . 1 Background . . . . . . . . . . . . 1 Study Objectives . . . . . . . . . . . . 5 STUDY ORGANISM . . . . . . . . . . 7 Distribution and Habitat . . . . . 7 Morphology . . . . . . . . . 7 Ecology . . . . . . . . . . . 8 DESCRIPTION OF STUDY AREAS . . . . . . . . . 13 Site Locations . . . . . . . . . . . . . 13 Climate . . . . . . . . . . . . . . l6 Geology and Soils . . . . . . . . . . . 18 Riparian Vegetation . . . . . . . . . . 24 Water Quality and Hydrology . . . . . . . . 24 METHODS AND MATERIALS . . . . . . . . . . . 29 Site Evaluation . . . . . . . . 29 Streamwater characteristics . . . . . . . 29 Substrate composition . . . . . . . . . 32 Riparian vegetation . . . . . . . . . . 33 Field Sampling . . . . . . . . . . 34 Life history and growth rates . . . . . . 34 Production estimates . . . . . . . . . 37 Laboratory Stream Study . . . . . . . . . 40 RESULTS . . . . . . . . . . . . . . . . 43 Streamwater Quality . . . . . . . . . . . 43 Physical and chemical parameters . . . . . 43 Nitrogen and phosphorus parameters . . . . 50 TABLE OF CONTENTS - Continued Life History . . . . Life cycle . . Sex ratios . . . Diet . . . . . . . . . . Production . . . . . . . . Density and standing crop biomass Annual production estimates . . Growth Rates . Natural stream growth rates . . Laboratory stream growth experiment DISCUSSION . . . . . . SUMMARY. . . . . . APPENDIX A - Physical and Chemical Water Data Tables APPENDIX B - Annual Production Estimate Data Tables LITERATURE CITED . . . . vi 95 111 113 118 122 10 11 LIST OF TABLES Temperature and precipitation data collected at nearest NOAA monitoring station to the Ford and Peshekee River sites from 1951-1980,1988 and 1989 . . . . . . . . . . Soil classes of townships containing the Ford and Peshekee River study sites . . . . . . Selected physical and hydrologic properties of common soils of the Ford River watershed within Dickinson County, Michigan . . . . . . Selected physical and hydrologic properties of common soils of the Peshekee River watershed within Baraga County, Michigan . . . . . . Calculated importance percentages of riparian vegetation at the Ford River (Fsl) site and the Peshekee River (PSl) site . . Percent composition of substrate particle size at the Ford River (F81) and Peshekee River (Psl) sites . . . . . . . . . . . . . . Summary (mean i S.E.) of selected water chemistry parameters for the Ford and Peshekee Rivers, 1988-1990 . . . . . . . . . . Results of paired t-tests between the Ford (FSl site) and Peshekee (PSl site) Rivers for selected water chemical, physical and nutrient parameters from July, 1988 to June, 1990 . . Gut contents of A. lycorias nymphs of the Ford and Peshekee Rivers, 8/11/90, 10/16/90 and 1/19/91 Mean density (no. ind. /m2) i S. E. ofA _. lycorias collected from the Ford (F81) and Peshekee (PSl) Rivers from June, 1988 to June, 1990 . Mean biomass (g dry wt. /m2) i S. E. of A. lycorias collected from the Ford (F81) and Peshekee (PSl) Rivers from June, 1988 to June, 1990 . . . 17 . 19 . 21 . 23 . 25 27 49 51 . 65 67 69 LIST? 12 13 14 15 16 17 18 19 20 21 22 23 OF TABLES - Continued Results of paired t-tests between the Ford River (F81) and Peshekee River (P81) for A. lycorias density and biomass from June, 1988 to June, 1990 . 70 Results of paired t-tests of A. lygorias densities and standing crop biomass at replicate sites within the Ford and Peshekee Rivers, July, 1989 . . 71 Mean ecological density (no. ind./m2 rock surface area) i S. E. of A. lycorias collected from the Ford (F81) and Peshekee (PSl) Rivers from June, 1988 to June, 1990 . . . . . . . . 73 Mean ecological biomass (g dry wt./m2 rock surface area) i S. E. of A. lycorias collected from the Ford (F81) and Peshekee (PSl) Rivers from June, 1988 to June, 1990 . . . . . . . 74 Annual production of A. lycogias at F81 and P81 calculated using the size-frequency method for 1988-1989 and 1989-1990 . . . . . . . . . .77 Mean dry weight (mg) i S. E. by year class of A. lycorias collected at F51 and P81, 7/1990 - 1/1991 . . . . . . . . . . . . 81 Monthly growth rates (l/day) i S. E. by year class of A. lycorias collected at F81 and P81, 7/1990 - 1/1991 . . . . . . . . . . . 84 Chemical and physical characteristics of hard and soft water treatments of laboratory growth study conducted from June to October 1990 . . . 87 Mean laboratory growth rates (1/day) of A. lycorias for 110 day period 1 S. E. in soft and hard water treatments . . . . . . . . . . . . . 90 Results of three factor unbalanced analysis of variance of A. lycogias growth in a laboratory stream experiment . . . . . . . . . 93 Mean prey and predator densities (no./sample) i S.E. and prey/predator ratios by size class of A. lycorias for the Ford and Peshekee Rivers, 7/15/91 . . . . . . . . . . . 101 Results of riffle and pool fish survey of F51 and P81 conducted during August 1990 . . . . . 108 viii OF TABLES - Continued Physical and chemical water quality of the For River (FSl site), Michigan, 1988-1990 . . . 113 Physical and chemical water quality of the Peshekee River (PSl site), Michigan, 1988-1990 . . . 114 Cation concentrations (mg/L) of the Ford and Peshekee Rivers from 1988-1990 . . . . . . 115 Nutrient water quality of the Ford River (FSl site), Michigan, 1988-1990 . . . . . . . . . 116 Nutrient water quality of the Peshekee River (PSI site), Michigan, 1988-1990 . . . . . 117 Calculation of production of A. 1ycoria§ at the Ford (FSl site) River, 1988-1989 . . . . . . . 118 Calculation of production of A. lycorias at the Ford (FSl Site) River, 1989-1990 . . . . . . 119 Calculation of production of A. lycorias at th Peshekee (PSl site) River, 1988-1989 . . . . 120 Calculation of production of A. lycogias at the Peshekee (PSl site) River, 1989-1990 . . . . 121 ix 10 11 12 13 LIST OF FIGURES Ford River study area and sampling location, Dickinson County, Michigan . . . . . . . 14 Peshekee River study area and sampling location, Marquette County, Michigan . . . . . 15 Length/dry weight regressions for A. lygggigs collected from the Ford (A) and Peshekee (B) Rivers. . . . . . . . . . . . 36 Seasonal variations in water temperature at the Ford (FSl site) and Peshekee (P81 site) Rivers, 1988-1990 . . . . . . . . . . . 44 Mean monthly discharge for the Ford (FEX site) and Peshekee (P81 site) Rivers . . 46 Seasonal variations in pH at the Ford (F81 site) and Peshekee (P81 site) Rivers, 1988-1990 . . . 47 Seasonal variations in total hardness at the Ford (F81 site) and Peshekee (PSl site) Rivers, 1988-1990 . . . . . . . . . . . . . . 48 Cation concentrations (mg/L) for the Ford River (A) and the Peshekee River (B), 1988-1990 . 52 Seasonal variations in orthophosphorus at the Ford (F81 site) and Peshekee (PSI site) Rivers, 1988-1990 . . . . . . . . . . . . . . 54 Seasonal variations in nitrate at the Ford (F81 site) and Peshekee (PSl site) Rivers, 1988-1990 . . . . . . . . . . . . . . 55 Size—frequency distribution by length of A. lycorias collected from the Ford River (A) and the Peshekee River (B), 7/90 . . . . . . . . . . . . 57 Size-frequency distribution by length of A. lycorias collected from the Ford River (A) and the Peshekee River (B), 8/90 . . . . . . . . . . . . 58 Size-frequency distribution by length of A. lycorias collected from the Ford River (A) and the Peshekee River (B), 9/90 . . . . . . . . . . . . 59 LIST OF FIGURES - Continued 14 15 16 17 18 19 20 21 22 23 24 Size- frequency distribution by length of A. lycorias collected from the Ford River (A) and the Peshekee River (B),10/90 . . . . . . . . 60 Size-frequency distribution by length of A. lycorias collected from the Ford River (A) and the Peshekee River (B), 1/91 . . . . . . . . . . . . 61 Mean gut fullness i S.E. of A. lycorias nymphs collected from the Ford (F81 site) and Peshekee (P81 site) Rivers; (A) Young of year, (B) Second year, (C) Third year . . . . . . . 63 Densities (A) and dry weight biomass (B) i S.E. of A. lycorias collected from the Ford (FSl site) and Peshekee (P81 site) Rivers, 1988-1990 . . . 68 Ecological densities (A) and ecological biomass (B) i S.E. of A. lycorias collected from the Ford (F81 site) and Peshekee (P81 site) Rivers, 1988-1990 . 75 Annual production of A. iycorias at F81 and P81 from 1988-1990 . . . . . . . . . . . . 78 Total annual A. lycorias densities (A), dry weight biomass (B), and production (C) by year class for 1988-1989 and 1989-1990 . . . . . . 80 Mean dry weight 1 S.E. by month of young-of-year (A), second year (B), and third year (C) A. lycorias nymphs collected from the Ford and Peshekee Rivers, 7/90-1/91 . . . . . . . . . . . . . . 82 Monthly growth rates 1 S.E. of young-of~year (A), second year (B), and third year (C) classes of A. lycorias collected from the Ford and Peshekee Rivers, 8/90-1/91 . . . . . . . . . . . 85 Mean log weights 1 S.E. of individual nymphs by sex (M or F), strain (F or P) and treatment (H or S) at start, mid-point and conclusion of laboratory growth experiment . . . . . . . . . . . 89 Mean growth rates of male and female A. lycorias nymphs reared in laboratory streams for 110 days . 91 xi LIST OF FIGURES - Continued 25 26 Mean growth rates of female (A) , and male (B) A. lycorias nymphs reared in laboratory streams for 110 days . . . . . . . . . . 94 Flow diagram of factors influencing annual production of A. lycorias nymphs in hard and soft water river systems. .........105 INTRODUCTION W The association between stream water hardness and invertebrate productivity has been investigated by Tarzwell (1938), Egglishaw (1968), Sutcliffe and Carrick (1973). Arnold et a1. (1981), and Collier and Winterbourn (1987, 1990). In each of these studies, greater invertebrate densities were found in streams with higher alkalinities or calcium concentrations. Additionally, Krueger and Waters (1983) reported a positive correlation between alkalinity and both invertebrate production and fish standing stocks in three Minnesota streams. However, none of the studies provided experimental evidence that cation concentrations were the mechanism controlling the observed correlations. Hynes (1970) discussed a variety of factors that have been demonstrated in the literature to influence benthic invertebrate abundances in streams, including current velocity, temperature, substrate type, disssolved oxygen, acidity, food supply, drought, spates, predation and water hardness. Several studies reviewed by Hynes (1970) regarding the relationship between water hardness and invertebrate productivity suggested that there was no relationship for some Ephemeroptera species (Illies, 1952; Armitage, 1958), Simuliidae (Grenier, 1949) or Sisyridae (Jewell, 1939). Many mechanisms responsible for the observed relationship between stream water hardness and secondary production have been suggested in the literature. First, a reduced efficiency of osmoregulation may be related to lower invertebrate production in soft water streams. Fiance’s (1978) study of Ephemerella growth rates in acidic streams indicated that lowered pH might account for significantly slower growth rates of mayfly larvae. He suggested that the osmoregulatory function in mayflies was affected, resulting in a greater energy expenditure for the maintenence of internal ionic balance. The increase in metabolic rate required to supply energy for active transport might tend to slow the organism's growth rate and overall production. Lechleitner et. a1. (1985) also reported an effect on the ionregulatory ability of stonefly nymphs due to acute acidic and alkaline pH. In both cases, osmoregulation was examined under extreme pH conditions for very short periods of time. Possibly, the osmoregulatory functions of invertebrates could also be affected by slightly lowered pH levels under chronic conditions. The difference in allochthonous inputs from one stream to another may also be related to lower production in soft water streams. Generally, hard water streams are located in primarily deciduous watersheds, while soft water streams are associated with more coniferous type watersheds. Both the timing and nutritional quality of the allochthonous inputs g4i13-'Vary in coniferous and deciduous watersheds (Fisher and “LikEDS, 1973). Differences between water chemistry parameters such as nitrate and pH may affect the detrital quality in hard and soft water streams. Higher nitrates associated with deciduous inputs in fall may tend to speed up decomposition rates within a hardwater stream (Suberkropp and Klug, 1976; Suberkropp and Chauvet, 1991). Likewise, pH and cation concentrations will determine the precipitation rates of dissolved organic matter (Lush and Hynes, 1973; Lock and Hynes, 1975). By increasing the surface area available for microbial colonization of particulates, a higher quality food source would be available to invertebrates. Additionally, differences in nutrient chemistry between streams may also alter autochthonous energy sources. Levels of primary production within a stream will affect grazer and collector- gatherer populations, and perhaps the higher trophic levels (Krueger and Waters, 1983; Fuller et al., 1986; Lay and Ward, 1987; Collier and Winterbourn, 1987, 1990). Finally, physical or biological factors may be influencing invertebrate densities and distributions in hard and soft water streams. The effects of temperature on egg diapause, embryonic development, optimal growth and metabolism of aquatic insects has been well documented in the literature (Vannote and Sweeney, 1980; Brittain, 1983; Sweeney and Vannote, 1986; Sweeney et. al., 1986a, 1986b; Lillehammer, 1986; Mutch and Pritchard, 1986; Hauer and 4 Benke, 1987; Soderstrom, 1988). Differences in water ‘cemperatures or degree-day accumulations will alter invertebrate productivity in a stream regardless of water hardness. Likewise, major differences in dissolved oxygen concentrations could play a role in invertebrate distributions within streams of differing water hardnesses (Knight and Gaufin, 1963, 1965, 1966). A large amount of work has been done regarding the effects of current velocity on invertebrate abundances (Kovalak, 1977; Walton et. al., 1977; Orth and Maughan, 1983). Many studies have suggested that hydrologic disturbances such as spates play a major role in determining invertebrate productivity and distribution (Minshall and Minshall, 1977; Siegfried and Knight, 1977; Stout, 1981; Peckarsky, 1983; Statzner and Higler, 1986; Hauer and Benke, 1987; Graesser, 1988; Power et. al., 1988; Resh et. al., 1988; Statzner et. al., 1988). Invertebrates also demonstrate a distinct preference for certain substrate types (Cummins and Lauff, 1969; Walton, 1978; McElhone and Davies, 1983; Reice, 1983, Brown and Brown, 1984; Minshall, 1984; Clements, 1987). Conceivably, differences between invertebrate production of a particular set of streams could be related to differences in hydraulic conditions or the amount of suitable substrate rather than stream water hardness. Finally, biological factors such as competition for food and space, and predation should be considered as controlling mechanisms in the stream community (Allen, 1951; peckarsky, 1983; Power, 1988; Feltmate and Williams, 1991). study Objectives The goal of this research was to gather quantitative data regarding production and growth of a stream invertebrate predator, Agrgpgggig lygggigs, in matched hard and soft water streams. Specific objectives of the study are the following: . Compare and contrast physical and chemical characteristics of streamwater, substrate composition, and riparian vegetation at stream sites of a hard and soft water stream. - Obtain dry weight production estimates of a invertebrate predator common to a hard and soft water stream. . Determine growth rates of an invertebrate living in its natural habitat, as well as in a controlled laboratory environment at high and low water hardnesses. . Predict the most likely factor(s) controlling the observed production estimates and growth rates in each stream. The physical and chemical characteristics of a hard and soft water stream were documented over a two year period. Production estimates were made, which were based on the null hypothesis of no production difference between sites, versus the alternate hypothesis that production would be positively related to stream water hardness. In this study, production was predicted to be greater in the hard water Ford River than in the soft water Peshekee River. A second set of hypotheses were developed to address the study's third objective. GfOWth rates were determined for organisms living in the natural environment and in the laboratory in hard and soft water treatments. The null hypothesis stated that growth rates would not differ significantly for organisms living in the natural environment or in the laboratory. The alternate hypothesis predicted that growth rates would be significantly higher in hard water streams and treatments due to less osmoregulatory stress. Finally, production and growth rate data were used to predict likely factors influencing production in each stream. STUDY ORGANISM Distribution and Habitat Actoneutia lygotias was chosen for this study because of its abundance in both the Ford and Peshekee Rivers and the organism's tolerance to handling for laboratory experimental purposes. A.lyco:ia§ is distributed over 21 states and provinces throughout the central and eastern United States and Canada (Stark and Gaufin, 1976; Peckarsky, 1979). The stonefly species is commonly found among rubble, and rocks of riffles and rapids in streams of various orders (Knight and Gaufin, 1967). Morphology Agronguria belongs to the family Perlidae, whose diagnostic characteristic is the presence of branched gills on the thoracic segments only. Within the Perlidae family, the genus Acrongggia may be identified by (1) an absence of a setal row on the occiput, (2) a postocular fringe of several thick setae, (3) three ocelli, (4) a basal fringe of setae on the cerci, and (5) a yellow M-shaped mark anterior to the median occellus (Merritt and Cummins, 1984; Stewart and Stark, 1988). Mature female nymphs may be distinguished from males by their larger size of 17-20 millimeters (15-18 mm for males) and the lack of a complete sternal fringe on the ventral posteromesal margin of sternum eight (Stark and Gaufin, 1976; Stewart and Stark, 1988). A. lycotias nymphs collected at each site and adults reared in the laboratory were keyed to species using Classen (1931) and Stark and Gaufin (1976). A positive identification of nymphs and adults was made by Dr. William L. Hilsenhoff of the Department of Entomology, University of Wisconsin-Madison. Museum specimens of the nymphs and adults of A. c ias collected in this study are included in the collection of Dr. Richard W. Merritt of the Department of Entomology, Michigan State University. Ecology Knowledge of the life history, growth patterns, trophic interactions and environmental requirements of a species is required to make accurate estimates of production. Frison (1935), Hynes (1976), Barton (1980) and Stewart and Stark (1988) have reviewed the ecology of the Plecoptera. The ecology of the genus Attoneuria has been reviewed by Peckarsky (1979). Detailed accounts of the life history and growth of A. californica and A. caroligensis have been published by Heiman and Knight (1975), Siegfried and Knight (1978) and Schmidt and Tarter (1985). Despite the widespread abundance of A. lyggrias, a thorough investigation of the life history of the species has yet to be completed. Peckarsky (1980) and Peckarsky and Dodson (1980) have examined the predator-prey interactions of Agronguria in the stream community. The following summary of the ecology of CrO eu ia represents observations from studies examining several different species of the genus. The distribution of Acroneuria is determined by dissolved oxygen concentration, pH, temperature, substrate type and current velocity (Peckarsky, 1979). The genus requires high concentrations of dissolved oxygen. Individuals will become stressed with sharp drops in dissolved oxygen concentrations and exhibit a "push-up" behavior to obtain the necessary oxygen (Knight and Gaufin, 1963, 1965). Because of the requirements for dissolved oxygen, Acroneuria is most abundant in stony substrates associated with riffles and rapids (Walton et al., 1977). Although Kroger (1974) suggested that Hesperoperla, a genus related to Acroneuria, was a strong swimmer, another study indicated that spates can cause the wash~out of Perlidae populations (Siegfried and Knight, 1977). Compared to other stoneflies, A. lycotias is relatively resistant to low pH. Bell and Nebecker (1969) calculated a TLm96 of pH 3.32 for A. lycorias. Water temperature has been shown to affect growth and emergence in Acroneuria. Temperature ranges for optimal growth of A. californica nymphs in the summer were 16° - 22° C, 6° - 12° C in the winter and 10° - 18° C during the spring and fall (Heiman and Knight, 1975). Emergence of A. abnotmis may be delayed up to two weeks due to cold water temperatures (Harper and Pilon, 1970). 10 The life cycle of A. lycotias has not been examined in any detail in the literature. Several authors have suggested a three~year life cycle (Peckarsky, 1979; Barton, 1980). Siegfried and Knight (1978) reported an l8-month life cycle for A. galltgtnigg, while Heiman and Knight (1975) observed a two-year life cycle, and Sheldon (1969) concluded that the same species lived for three years. Other life history studies have documented a 1-year cycle for A. evoluta (Ernst and Stewart, 1985) and a 2-year cycle for A. carolinensis in West Virginia (Schmidt and Tarter, 1985). Growth rates have been investigated for A. californica (Heiman and Knight, 1975; Siegfried and Knight, 1978) and for A. carolinensis (Schmidt and Tarter, 1985). Field studies of A. gatolinensis indicated that female growth was greatest in August, while growth rates for males were highest in October. In this study, as well as in Siegfried and Knight's (1978) study of A. califgtnica, the smallest nymphs exhibited the greatest relative growth rates. Heiman and Knight's (1975) laboratory study of A. galifognica reported a net growth efficiency of 41%. Growth rates for all nymphs were greatest in the summer, lowest in the winter and intermediate in spring and fall. Maximum laboratory growth rates approximated growth rates calculated from field data. Emergence of A. lycorias was reported to occur anytime between mid-April to early August by Peckarsky (1979). Barton (1980) collected A. lycotias adults in low numbers in 11 Alb9rta, Canada in mid-June. Harper and Pilon (1971) found that A. Lycotias in Quebec, Canada emerged for an extremely short period of time in early June. They noted that only a few adults were caught in their traps. Likewise, Narf and Hilsenhoff (1974) mentioned difficulties in collecting adult A. lycorias even though nymphs and exuviae were abundant in Otter Creek, Wisconsin. They suggested that the adults inhabited the tree canopy, making the collection of adults difficult. Adults that were reared in their laboratory at an unspecified temperature emerged in May. Data regarding sex ratios, fecundity, and egg development for A. lyggtigs is non-existent in the literature. The food habits of Acroneugig is well documented in the literature. Shapas and Hilsenhoff (1976) reported that A. lycotias preyed primarily on Chironomidae and Hydropsychidae. Other sources of food for Acroneuria and related species include Simuliidae and Hydropsychidae for A. californica (Heiman and Knight, 1975), Chironomidae, Hydropsychidae, Tipulidae, Elmidae, Leptophelebiidae, Philopotamidae, and Baetidae for A. abnotmis (Johnson, 1981), Baetidae, Chironomidae, Rhyacophilidae, Brachycentridae, Psychomyiidae and Perlidae for A. pacifica (Richardson and Gaufin, 1971), Chironomidae, Capniidae, Leutridae, Nemouridae, Taeniopteryidae, Perlodidae, Baetidae, Ephemerellidae, Glossosomatidae, and Hydropsychidae for A. gatolinensis (Schmidt and Tarter, 1985). There is some evidence that 12 detritus and plant matter makes up a portion of Attoneutia sp. diet. Richardson and Gaufin (1971) found that 11.7 percent of the diet of A. pacifica consisted of plant materials. Siegfried and Knight (1976b) reported that twenty to sixty-two percent of the A. gglifigtnigg foreguts examined contained detritus. Additionally, selectivity of prey items by Agnoneutig sp. depends on prey size and availability. Larger nymphs ingest larger prey items, and the proportion of a particular prey item consumed is related to prey populations in the environment (Sheldon, 1969; Siegfried and Knight, 1976a). - “u d“, _- .I.-. .1- . iv: o-Iam.~unm.\\..1._—s..\s- .. DESCRIPTION OF STUDY AREAS Site Logations The close proximity of the hard water Ford River and the soft water Peshekee River to one another in Michigan’s upper pennisula, along with the fact that both rivers are relatively unimpacted by anthropogenic activities provided a good opportunity for this study. Fourth-order sites on the Ford and Peshekee Rivers were chosen where the physical and chemical water characteristics, riparian vegetation, and land uses were as similar as possible. The headwaters of the Ford River are located near the county line between Iron and Dickinson County. The stream flows eastward, draining the central and southeastern parts of Dickinson County before entering Green Bay of Lake Michigan (Figure 1). The Peshekee River lies north of Lake Michigamme in Marquette and Baraga County. It originates near Mt. Curwood, the highest point in Michigan, and flows in a southeast direction to Lake Michigamme (Figure 2). The primary site on the Ford River is located along County 426, approximately 12 miles west of Ralph, Michigan (T. 43 N., R. 29 W., Sec. 16). The site is referred to as Eord Site 1 (F81) in this report. Peshekee Site 1 (P81) was the primary soft water sampling site (Figure 2). It lies along County 607, approximately 4 miles north of Lake 13 I I \ \ 1 —- = Road ‘Channlng l - augwfli O Q“ r-v .oo ‘\ F52 14 I 0*” S" 3 O E I.’ ".\\ F31 x“ ..o~.. Ralph Ford River Figure 1. Ford River study area and sampling location, Dickinson County, Michigan. '— ‘\ t. \‘ Cunwood . ~ > \\ Baraga ‘ ., - .‘ Creek . \ Peshekee River p32; 1 N '69“ T PS1 o\5““° \\ Lake Mlchlgamme A‘champlon 1 ml. Road Figure 2. Peshekee River study area and sampling location, Marquette County, Michigan. 16 Michigamme (T. 49 N., R. 30 w., Sec. 2). F81 and P81 were fflonitHDIGd from June, 1988 to June, 1990. In addition to the two primary sites in each river, the invertebrate community was sampled at a second pair of matched sites. The second set of sites were sampled during the summer of 1989. 'mat In a comparison study such as this one, it is desirable to keep climatic variables such as air temperature, rainfall, and snowfall as similar as possible. Although the distance between watersheds is less than 65 miles, some climatic comparisons should be noted. Climatic data collected at the nearest monitoring station to the Ford River (Crystal Falls) and the Peshekee River (Champion) are presented in Table 1. Historically, the difference in mean daily air temperature between sites has been small. Mean daily air temperatures at both sites during 1988 were approximately 1° F warmer than the daily mean for the period from 1962 to 1980. Temperatures were normal at Crystal Falls during 1989, but were below normal at Champion. Freeze dates (last date 32° F or below in spring and first date 32° F or below in fall) are different for each of the watersheds. With a probability of five years in ten, the last freeze date in spring is seven days later at the Peshekee than at the Ford River. Likewise, the first freeze in fall is seven days earlier at the Peshekee River. 17 Table 1. Temperature and precipitation data collected at nearest NOAA monitoring station to the Ford and Peshekee River sites from 1951-1980, 1988 and 1989.1 SI l' I |' Crystal Falls Champion Parameter (Ford River) (Peshekee River) Wm (0F) Average Daily (1951-1980) 38.28 38.8 Average Daily (1988) 39.8 39.6 Average Daily (1989) 38.3 37.4 Last Freeze in Springb (32 0F or lower) May 29 June 5 First Freeze in Fallb (32 0F or lower) Sept.17 Sept.10 Precipitation (Inches) Average Total Rainfall 29.8 33.7 (1951-1980) Total Rainfall (1988) 28.8 36.0 Total Rainfall (1989) 22.9 26.4 Average Total Snowfall 70.6 138.0 (1951-1980) Total Snowfall (1988) 79.0 143.2 Total Snowfall (1989) 59.0 162.6 1‘Data from NOAA, 1988 and 1989, Berndt, 1988 and Linsemieer, 1989. aAverage daily temperature at Crystal Falls recorded 1962- 1980. bDate represents a probability of five years in ten. Data recorded at Iron Mountain, MI. (Benerally, the Peshekee River watershed receives greater anmnults of rainfall (Table 1). Average precipitation was below normal during 1988 and 1989 at Crystal Falls and during 1988 at Champion. A large difference between sites is observed when comparing average snowfall totals. The Champion area receives an average 138 inches of snowfall per year, almost twice as much as the amount received in Crystal Falls. During the winter of 1989, the difference in total snowfall between sites increased to almost a three-fold difference. This large difference in snowfall, along with slight differences in freeze dates within each region will directly affect the amount and timing of snowpack runoff each spring. Geo o a d o' s The topography in the Ford River region consists of narrow swampy lowlands with adjacent hills and small areas of exposed bedrock (Table 2). Elevation ranges from 1500 feet above sea level, near the headwaters of the Ford River, to 1100 feet with an average elevation of 1200 feet (Hendrickson and Doonan, 1966). Stream velocities are relatively low, the average drop in elevation is about eight feet per mile (Snider, 1977). Northern portions of Dickinson County are composed of rolling moraines, flatter till plains and outwash plains. The glacial drift consists of sand, limestone fragments, silt, clay, cobbles and boulders (Russell, 1907; 19 Table 2. Soil classes of townships containing the Ford and Peshekee River study sites.T W123). Ford Site 1 Peshekee Site 1 T.43, R.29W T.49, R.30W 8011 Class Swamp and lake 5 5 Rock knobs 5 28 Sandy till 18 -- Sandy gravel 8 3 IData from Leverett, 1911 20 gendrickson and Doonan, 1966) . Portions of the Ford River studied in this project are underlain by Middle Precambrian igneous, sedimentary and metamorphic rocks (gneiss, granite and schist) and slates, dolomites and quartzites of Cambrian and Ordovician age (Hendrickson and Doonan, 1966; Snider, 1977). Soils in the Ford River watershed range from mucks of the Carbondale-Cathro and Waucedah-Cathro complexes to sand, with large areas of Pemene and Emmet sandy loam (Table 3)(Linsemier, 1986). Most soils found in this region were formed from glacial till deposited by retreating glaciers. Slopes are not very steep (0-18%). Soils are generally neutral in pH reflecting the large amount of sandy till in the watershed. Hydrologic soil groups and permeability values, useful in estimating runoff from precipitation and characterizing the soil’s ability to transmit water, are presented in Table 3. Both parameters indicate the rate of downward movement of water within saturated soils. Most Ford River soils are classified as group A or B, having high to moderate infiltration rates. Permeability ranges from 0.2 to 20 inches of precipitation per hour, with most soils demonstrating moderate permeabilities of 0.2 to 6.0 inches per hour. The high percent organic matter (Table 3) also contributes to the high rates of infiltration. The Peshekee River watershed is characterized as a region of "hills and bluffs of gneiss separated by lowlands .‘VQJ‘N 'c (1'. '5’ IL”. .{L‘."" ’ " m a .. a a O ., 4 a . n ., moon coaumuuaflmcfl 30am >Hw> u a mzouw oumu coaumuuaflmca 30am 0 macaw mumu coaumuuafimcw oumumooz n m dsouw oumu c0flumuuaflmcfi coax I 4 ddouwm .mmma .uoafiomcwq Eouu suma+ Hum.o m.wum.c omuo.w m mno m.o one» coofinom NIH m.mnm.¢ omlo.m a one ~.H can» mean omonnsom 8-2 «SAG o.e-~.o o o Tm 63:8 858 unopposmz mam.o m.>nm.¢ o.mnm.o m ore m.m .Eooa Sodom deem mememm muH e.o|w.m o.w|w.o m mic N.> awed moon» 1. mean ocean 2 mum.o m.bum.¢ o.mum.o m warm o.m eaoa moon» Team oedema TH «8-9m 0.8-8.0 m flue m5 53 8:3 mean poeam manoc w.mnm.m o.m|~.o n\¢ o ¢.om axons oununo toamoconumo 3.. mm 1 .8155. «965 3. 3560 052 .. umuumz lavage—moaned camoaouomm macaw sunny“; 30m cacMOHO Amvucouxm e.cmmaa0Hz .mucsoo acmcfixoflo canvas oonmumumz uo>flm onom onu mo mHHOm coeeoo mo mofipuodoud camoHonomn one Andammzm oouooaom .m magma 22 arid swamps" (Seaman, 1944). The bluffs have exposed rock surfaces on several sides with vegetation covering most north slopes as well as the bluff tops. The Peshekee Uplands located in the east-central portions of Baraga and western Marquette Counties range in elevation from 1400 to 1890 feet above sea level. The bedrock of the lower Precambrian age is predominately gneiss and Laurentian granite with lesser amounts of schist (Seaman, 1944; Doonan and Byerlay, 1973). Some portions of the region are covered with a very thin layer of glacial drift. The immediate area surrounding the work site on the Peshekee River consists strictly of exposed rock knobs, swamps and sandy gravel (Table 2). Headwaters of the watershed consist of extensive areas of swamps. Soil types found in the Peshekee Uplands consist largely of nearly level mucks (Carbondale and Tacoosh), hilly Michigamme-Rock outcrop complexes and Champion-Michigamme cobbly silt loams (Table 4)(Berndt, 1983). In contrast with the Ford River soils, the soils associated with the Peshekee River are low in permeability (0-6.0 inches/hour) and belong to hydrologic groups of moderate to very slow infiltration rates. pH of the soil groups are generally acidic (Table 4). The percent organic matter ranges from 0 - 85%, depending on the soil type. 1-1 . «Vet _ . oomu coaumuuawmcfi 30am hum> a a macaw oumu cowumuuawmcfi 30am n O macaw oumu coaumuuawmcw wumuwooz I m ozone moon coauouoflnucfl none n a asouoo .ommfi .uocuwm scum ounce . “1 7’ 7"“ ""|.’~"J|"N“ (1"..“Js‘. ., _ m-o o.o-m.e o.~-o m mmumn «.0 good has» I . w wannoo annex mmnmm m.mnm.m o.mn~.o o\< o m.H named ooozcoouo pom consmo neume m.e-m.e o.m-~.o o\m o m.~ xmaosoo gnooooa Ixownufi3 mun m.o-o.m o.muoo.o o\m mane H.m good uafln adenoo deadmwnowz IcoadEmno m“ muo m.mum.m o.~no O mmuma m.m woadaoo dououoo xoomloeadmfinoflz muH m.mim.m o.~|m.o o\< mmnma m.v Emoa uafln mannoo meadmflcowz Ico«QEmno x mbuov m.>na.m o.mnm.o o\< o H.oH axons cocoons Ioauoconumo Ame rd A.um\.ch omaouw Amy hucsou oEHz umuumz. SuwaflnooEuom” camoaouomm macaw casuflz Hwom oflcoouo .wvuoouxm +.cmmflcofiz .>DGDOO mmmuom canoe: venomoum3 Hm>fim omxonmmm on» no mason coEEoo mo mofiuuodond camoHouoma oco Hmoammnd oouooaom .e manna 24 'Fhe headwaters of the Ford River are located within areas of vegetation dominated by northern white cedar (m occidentalis) and speckled alder (Alnus rugosa). Extensive tamarack and alder swamps, and sedge meadows characterize the upper reaches of the Peshekee River and its tributaries. At the Ford River site the dominant vegetation, calculated as importance percentages, consists of balsam poplar (Populus balsamifera) and speckled alder (Table 5). Ninety-five percent of the Ford River vegetation is composed of deciduous species, while the majority (52%) of the vegetation at the Peshekee site is made up of coniferous species such as balsam fir, white spruce and white cedar. Watet Quality and Hydtology The streamwater characteristics of each river is determined by a combination of climatic, geological and vegetative conditions within their respective watersheds. The Ford River flows through ion-rich, high water capacity soils supporting deciduous type vegetation. The brown water, high alkalinity (~ 133 mg CaCO3/L) stream maintains a stable flow with seasonal fluctuations in spring and fall. Mean annual nitrate concentrations (~ 78 mg NO3/L) in the Ford are slightly higher than those measured in the Peshekee (~ 75 mg NO3/L). Mean annual orthophosphorus concentrations are similar in both streams. The low alkalinity (~ 14 mg 25 rrable 5. Calculated importance percentages of riparian vegetation at the Ford River (F81) site and the Peshekee River (PSl) site. Ford River (%) Peshekee River (%) MW 42 Ahieahalsamea 37 (Balsam Poplar) (Balsam Fir) Alnusrngaaa. 32 Acerrnhmm 16 (Speckled Alder) (Red Maple) Brnnusnensxllanica 9 Betnlananxrifera 16 (Pin Cherry) (Paper Birch) Betnlananxrifera 6 Alnnsrngosa 14 (Paper Birch) (Speckled Tag Alder) Ahieshalsamea 5 Biceadlansa 8 (Balsam Fir) (White spruce) comasiglcnifera 4 Thujadccidentalis 7 (Red-Osier Dogwood) (Northern White Cedar) Illnmsamericana 2 Acersnicatnm 1 (American Elm) (Mountain Maple) 26 CaCOB/L) Peshekee River is influenced strongly by its swampy headwaters, which contribute the tannins and lignins that stain the river a dark brown to black color. The watershed’s thin poorly drained soils and exposed granitic bedrock account for the river's low cation and anion concentrations, as well as it's fluctuating and flashy nature of streamflow. The high spring runoff of a large snowpack can drive a normally neutral pH down to 5.6 (Nancy Fegan, personal communication; Merna and Alexander, 1983). Both rivers maintain the cold water temperatures and high dissolved oxygen concentrations required by sensitive aquatic invertebrate and trout populations. The Ford and Peshekee Rivers have remained relatively free of any anthropogenic disturbances over time. State highway M-95 crosses the Ford River 11 miles upstream of the study site which may be responsible for chloride additions from road salt in the winter. A mink and cattle farm, a possible source of nutrients, is also located near the Ford's headwaters. Both watersheds have been influenced by scattered camps located along the rivers, as well as clearcut logging. The substrate composition at the study sites within each stream is dominated by cobble (Table 6). A greater proportion of the Peshekee River site consists of boulder substrate, while the Ford River site has a larger percentage of pebble and sand. Personal observations of other sites 27 Table 6. Percent composition of substrate particle size at the Ford River (F81) and Peshekee River (P81) sites. Particle sizes based on the Wentworth classification scheme (after Cummins 1962). Percent Composition (%) Substrate Ford River Peshekee River Particle Category (F81) (P81) Boulder 3 10 Cobble 75 74 Pebble 12 8 Gravel 0 3 Sand 10 5 28 along the Ford River indicate that the substrate alternates between runs and pools with sand substrate, and riffles with cobble and pebble substrate. In contrast, the Peshekee River consists of long runs with cobble and boulder substrate and occasional pools with sand substrate. Additionally, the smooth cobble and boulder substrate observed in the Peshekee River appeared to be extremely well weathered. MATERIALS AND METHODS site Eyaluation 1. Streamwater characteristics Chemical and nutrient water data were collected in order to match sites as closely as possible for Agtgneuria production and growth studies. Water chemistry and physical stream data were measured every two weeks during the summer months of June, July, August and September during 1988, 1989 and 1990. Chemical and nutrient samples were collected every six weeks for the remaining months of the year from September 1988 to June 1990. Water samples from each site were collected in polyethylene bottles, placed on ice during transport to the the field laboratory and analyzed within six to eight hours for alkalinity, hardness, pH, conductivity and turbidity. Two 250 mL dissolved oxygen samples per site were collected, immediately fixed and later analyzed in the field laboratory. Nutrient samples, also collected in polyethlylene bottles, were immediately frozen (or refrigerated for silica) and analyzed six months later using a Technicon® AutoAnalyzer II. Specific analytical procedures used are as follows: W Te e ature ° - Temperature was measured to nearest 0.5 °C in the field with a hand thermometer. 29 30 RE - pH was measured using an Oriono Model 407A Ionalyzer. Condugtivity - Conductivity measurements were made using a YSI° Model 31 Conductivity Meter. Values were corrected to 25 °C using the correction factor: Conductivity (umhos/cm) x (1 + 0.02 AT), where AT equals the difference between the observed water temperature reading and 25 °C. Tgrbigity - Determinations were made using a Each0 Model 2100A Turbidimeter. '3 ve x on O - D. O. was measured using the sodium azide modification of the Winkler method (APHA, 1980). Pgtgent Satgration ofi Dissolved Qxygen - Each D.O. value was converted to percent saturation using the formula: [D.O./(468/(31.6 + T))] x 100, where T equals water temperature (°C) at time of sample collection and D.O. equals dissolved oxygen concentration in ppm. A;Agligity - Total alkalinity was determined by the titration method described in APHA, 1980. figgggggg - Total hardness was measured by the EDTA titrimetric method (APHA, 1980) using Hacho powder pillows for indicator. 31 Si;ica - Determinations were made using the automated molybdosilicate method (U.S.E.P.A., 1979). h i e - Chloride measurements were made using the automated ferricyanide method (U.S.E.P.A., 1979). Soluble reactive ‘ L us and Total P“ L u: - Phosphorus was measured using the automated ascorbic acid reduction method (U.S.E.P.A., 1979). Soluble reactive phosphorus samples were filtered through 0.45 pm MilliporeO membrane filters before freezing and analysis. Organic phosphorus samples were digested with sulfuric acid before analysis. Nitratg - Nitrate determinations were made using the automated cadmium reduction technique (U.S.E.P.A., 1979). flittite - The automated sulfanilic acid/NED dihydrochloride method was used to determine nitrite concentrations (U.S.E.P.A., 1979). W - Ammonia was measured using the automated phenate method (U.S.E.P.A., 1979). Organic nitrogen was digested before analysis with sulfuric acid and measured as for ammonia. Concentrations of the common cations Ca2+, MgZ+, Na+ and K+ were measured on a regular basis from 1988 to 1990. Samples were collected in polyethylene bottles, frozen and 32 later analyzed via atomic absorption spectrophotometry at the Michigan State University Soils Testing Laboratory. Discharge was measured periodically at each site during the summers of 1988 and 1989 using a Gurley pygmy current meter. Velocity measurements were made at 0.6 of the depth below the water surface, for a minimum of 20 intervals per transect. Discharge was calculated by multiplying depth by interval width by mean velocity for each interval, and summing across the entire transect. Means 1 standard error for several of the important chemical and physical characteristics of the streamwater at each site were calculated on an annual and seasonal basis. Additionally, these parameters were compared statistically between sites using paired t-tests on the entire data sets using untransformed data. Data were checked for homogeniety of variances using Hartley’s test (Ott, 1988). 2. Substrate composition The compostion of substrate particle size was quantified within each site to determine whether substrate differences existed. Approximately 300 meters2 of stream bottom at each site were examined. Ten transects, 4 meters apart, were set up across the width of each stream. General particle sizes at ten equidistant intervals along each transect were identified using Wentworth’s classification scheme (Cummins, 33 1962). The percent composition of boulder, cobble, pebble, gravel and sand present was calculated on a per area basis. Additionally, the surface area of cobble-size rocks per square meter of stream bottom were compared at F81 and P81 using rocks collected during Hess sampling for invertebrates. Two measurements, short-axis circumference and long-axis circumference, were recorded for all rocks with a minimum short axis circumference of 80 millimeters. Calculated rock surface areas were determined by multiplying the short-axis circumference by the long-axis circumference for each rock collected. Actual rock surface areas of 45 foil-wrapped rocks from each stream were measured using a LI-COR® leaf area meter. Total rock surface area per sample was determined using calculated rock surface area/actual rock surface area regressions developed for each stream. These data were used in Acroneuria ecological density and biomass calculations described in the field sampling methods. 3. Riparian vegetation The importance of individual species within the riparian community was estimated by calculating importance values of dominant trees and shrubs at each site (Brower and Zar, 1984). The importance value index is the sum of the relative frequency, density and coverage for a particular species. Five rectangular plots (7 x 14 meters) were randomly chosen along the stream bank up to 150 meters upstream of each 34 invertebrate sampling site. Each tree, shrub and sapling within a plot was identified and counted. Coverage area was determined from measurements of the diameter of the crown of foliage for each individual plant. Relative frequency, density and coverage for each species was summed and divided by three to obtain an importance percentage. While this calculation has the disadvantage of giving similar values for different combinations of the three relative values, it provides a qualitative estimate of riparian species (Brower and Zar, 1984). M439 1. Life history and growth rates Basic knowledge of aspects of A. lygotias life history was critical for accurate production estimates. Since data were not available in the literature, an effort was made to obtain data regarding the cohort production interval (CPI, Benke, 1979) of A. lycgtias found in the northern Michigan geographical region. A series of intensive sampling efforts were made over a six month period, where a minimum of 150 individuals per site were collected using a 1.0 mm mesh kick screen. Individuals larger than 1.0 mm were sorted from debris and other organisms in the field using a white enamel pan and forceps, and were preserved in 90% ethanol. In the laboratory, organisms were measured to the nearest 0.5 mm under 10x power of a dissecting stereomicroscope. The sex of 35 second and third year nymphs were also recorded. All individuals were saved for stomach content analyses. Cohorts were identified by examining the data for peaks in size— frequency distributions. Mean length and standard errors were calculated for each sex and cohort. Mean dry weight biomass was calculated from length-weight regressions developed for A. lycorias nymphs collected from each stream (Figure 3). Growth rates were calculated using the instantaneous rate of growth equation: wt/wo = th where G = instantaneous rate of growth Wt = weight at time t We = weight at t = 0 t = time (Ricker, 1975) In this study Wt and We were represented by the mean dry weight biomass of a cohort on each sampling date. The sex of each mature nymph was determined by examining the posterior fringe of the eighth abdominal segment. The sex ratio of each cohort was calculated by dividing the number of females by the number of males. Gut contents of all three cohorts of A. lygotias were examined from samples collected in August and October, 1990 and January, 1991. The stomach contents were analyzed to provide a cursory look at food habits of various cohorts in each stream. The foreguts of six individuals per cohort per 0.08 i 0.06 - 0.04 - Dry Wt (9) 0.02 - 36 (A) y s 1.29189-5 ‘ x"2.8373 R"2 = 0.971 0.00 0.06 0.05 '1 0.04 - 0.03 -' Dry Wt. (g) 0.02 - 0.01 - trio's-l-uuw'v-uvluuIII-wu-I 5 10 15 20 25 30 Length (mm) (B) y s 1.01859-5 ' x"2.8813 R42 = 0.968 0.00 TIIII‘II'III I'I'II'I'II‘I‘I . . . 5 1o 15 20 25 30 Length (mm) Flgure 3. Length/dry welght regresslons for A. m; collected from the Ford (A) and Peshekee (B) Rivers, 1988. 37 site inere removed by cutting the membrane between the head and tfluorax and pulling the head from the rest of the nymph’s body. The foregut usually broke away from the hindgut cleanly. Each gut was gently teased open with a fine probe under a dissecting microscope. Stomach contents were identified to the order level (in some cases to the family level) and enumerated. Foregut fullness was determined by examination only and recorded as empty, 25%, 50%, 75% or 100% full. Mean gut fullness was calculated for each cohort (n = six individuals) and expressed as a proportion. 2. Production estimates Invertebrate samples were collected with the objective of obtaining a quantitative estimate of A. lycorias production at matched sites in the Ford and Peshekee Rivers. Beginning in the summer of 1988 invertebrate samples were collected with a modified Hess sampler (0.0881 m sample area) at two sites in each stream on an alternating two-week (or once-a-month) schedule. This sampling regime was changed at the end of September to a sample collection at one site per stream every six weeks for the fall, winter and spring seasons of 1988, 1989 and 1990 due to sample processing and ice-cover considerations. Sample collection was increased to a twice-a-month regime at one site per stream during the summer of 1989. 38 1%! limiting the sampling regime to two streams, one hard watEr and one soft water stream, and limiting the sites within each stream to one, this study fell under the definition of a pseudoreplicated study (Hulbert, 1984). Since only one stream of each stream hardness was sampled in this study all conclusions are limited to these particular streams. An additional site in each stream was sampled in July, 1989 to get a general idea of whether F81 and P81 were representative of other fourth-order riffles in the streams. Density and standing crop biomass values for A. lycorias nymphs collected at each of these additional sites were compared to values obtained at F81 and P81 using a paired t- test after testing for homogeniety of variances. Six samples were collected in riffle areas from two stratified random transects per Site. Three points along each transect were randomly chosen for sample collection, with care taken to avoid sampling in places that had been previously disturbed. Individual rocks were first rubbed by hand to dislodge invertebrates clinging to the rock surfaces, and then removed from the stream for substrate analysis. The remaining substrate was stirred up by hand to a depth of five to seven centimeters for a 30 second time period to allow the current to carry organisms into the sampler's 560 micrometer mesh netting. Samples were preserved immediately in 90% ethanol for later sorting. 39 In the laboratory, invertebrate samples were sorted for A. léfliggias nymphs, which were counted and measured using a dissecting stereo microscope equipped with an ocular micrometer. The length from the tip of the head to the end of the abdomen of each individual was measured to the nearest 0.5 mm under 10 x power magnification. Nymphs were divided into 0.5 mm size classes, which ranged from 1.0 mm to 24 mm. No attempt was made to identify instars. Length data were converted to dry weight for biomass and production calculations using length/dry weight regressions developed for each stream (Figure 3). Density and biomass values were compared using a paired t-test after testing for homogeneity of variances with Hartley's F-max test. Differences between sites for density and biomass data were compared with unpaired t-tests. Production was estimated using the size-frequency method (Hynes, 1961; Hynes and Coleman, 1968; Hamilton, 1969). Dry weight biomass losses were summed over the entire sample collection period for each 0.5 mm size class. After multiplying by the total number of size groups, the weight loss of each size group was summed to produce an estimate of total production. Negative weight loss values were included in the final sum. Total production was corrected for the cohort production interval (CPI) by multiplying the estimate by 365/generation time (Benke, 1979). The CPI was determined independently as part of the life history portion of this 40 studéf- The cohort turnover ratio (P/B) was calculated by d1Viding total uncorrected production by the annual dry weight biomass standing crop. The annual turnover ratio (P/B) was calculated by dividing the cohort P/B ratio by the CPI correction (Benke, 1984). Labgratozy Stteam Study Growth studies were conducted in the laboratory to determine growth rates of organisms living in hard and soft water. Transplant experiments were set up in two artificial streams (one stream simulating the Ford River and the other simulating the Peshekee River) in Felch, Michigan during the summer, 1990. The experiment was set up as a three factor factorial design with the strain and sex factors randomized within each treatment. Each stream contained 30 nymphs transplanted from hard water (approximately 15 individuals of each sex) and 30 nymphs taken from soft water (approximately 15 individuals of each sex). Organisms were held individually in cages built from 12 ounce clear plastic cups with screened panels to allow water to flow through the cages. Cages were cleaned and rerandomized within each stream every three days. Each nymph was fed one live waxworm every three days. Nymphs ate the commercially available food source readily in food trials conducted prior to the growth experiment. 41 Stream water from the Ford and Peshekee Rivers was transported to the field laboratory June 22, 1990 and was added to each recirculating stream. The water temperature was set to 15° C. The temperature was kept constant throughout the experiment. Since the artificial streams were located out-of—doors, the light/dark cycle followed natural photoperiods. The water temperature, pH, conductivity, alkalinity, hardness and dissolved oxygen was monitored at the start, at two-week intervals and at the end of the experiment. The stream water in each stream was exchanged with new stream water from the Ford and Peshekee Rivers at the mid-point of the experiment. The experiment was ended on October 10, 1990 when low ambient air temperatures made it impossible for the stream compressors to maintain 15° C. An initial, mid-point (41 days) and final (110 days) wet weight measurement was made for each individual. Measurements were made to the nearest 0.0001 gram using a Mettler® analytical balance after blotting nymphs with a paper towel to remove excess moisture. The error associated with using wet weights of nymphs was calculated by weighing a wet nymph fifteen times to obtain a mean weight and standard error. The sex of each nymph was determined using a dissecting microscope after final weight measurements were taken. Growth rates of each individual were calculated using the instantaneous rate of growth equation. Significant differences of individual growth rates between treatments, 42 sexes, and strains were calculated using a three-way analysis of variance. RESULTS Streamwater Quality 1. Physical and chemical parameters The complete water chemistry data set collected at Eord Site 1 (F81) and fleshekee Site 1 (P81) from July, 1988 to September, 1990 is presented in Tables A-1 and A-2. Air and water temperatures represent an instantaneous measurement of each parameter taken on that date. Continuous data recording instruments such as thermographs or min-max thermometers were not used in this study. Seasonal water temperatures followed similar patterns within each stream over the study period (Figure 4). Typically, temperatures in summer reached 20° C and above at each site. Although water temperatures during the summer, fall and spring of 1989 were higher at each site than those measured in 1988, it is not known whether this reflects true temperature differences, or is merely an artifact of the measurement technique. Discharge measurements made during 1988 and 1989 were inconsistent between sites, a result of an alternate sampling regime and differences in runoff rates for each watershed. To get an idea of the pattern of discharge for the Peshekee River, monthly data were obtained from the U. 8. Geological survey in Lansing, Michigan for the period between 1975 and 1977 (the most recent data available) for a site located 43 g F81 P81 z 44 301 10- O N (9.) umuedmu Jot-M the Ford (F81 she) and Peshekee (Ps1 site) Rlvers, 1988-1990. Figure 4. Seasonal varlatlons (mean i S.E.) In water temperature at 45 downstream of the P81 site. Since the west branch of the PeShekee, a major tribuatary, increases the discharge of the river significantly, mean monthly discharge at the P81 site was estimated using a discharge regression between the sites developed during Summer and Fall 1991 (y = -0.051263 + 0.43101 x; r2 = 0.99; y = discharge in m3/sec at P81 and x = discharge in m3/sec at U.S.G.S. site). Discharge for the Ford River was estimated from 1983-1990 data collected continuously from May to November at the PBX site as part of the E.L.F. monitoring project. No major tributaries flow into the Ford River between PBX and F81. Winter (December through March) discharge data for the Ford River was not available. A plot of mean monthly discharges of the two rivers indicates that the spring and to a lesser extent, fall periods are the most variable (Figure 5). Discharge data plotted for the months of April and May indicate that the snowpack runoff at the Peshekee River is much greater than that at the Ford River. Variations of conductivity, total alkalinity, total hardness and pH data collected over the entire period and on a seasonal basis reflect their close relationship with stream discharge (Figures 6 and 7, Tables 7, A-1 and A-2). During summer low flow periods, measurements of these four parameters all increased and likewise decreased during periods of high flow. Values for the entire data set for each parameter differed significantly (p < 0.05) between 46 .8283 .835 822.5... ......_.m 22. 38 32: Bo“. £3.22 ..m.o.m.= 52. use 32: 69.28.. £258..» 5e 69.28.. o5 .8.» xmue Po“. 2: to. 6928... 25.3.: :8: .m 2.6.“. W \ a a a a a a 1 o . o .. o. . «a j .m 69.28.“. E .. I res“. D -9 um— (ou/sw) cannula 47 P81 U F81 I \\‘ \M M \\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\‘ ... I——t I ' I ' I - I - I O co to V N o ,. Hd Seasonal varlatlons (mean i S.E.) In pH at the Ford (F81 slte) and Peshekee (PS1 she) Rlvers, 1988-1990. Flgure 6. .8288 .225. .2.» 51.8588 ace 6..» em": 20.... 05 «a 30:22. .82 e. and H coo—5 28:25. .9833. .n 952“. .m. M n: my .mo M d m. m m m w m m m % IO low 8 4 I00? . o9 [II 5.1 E f _ _ . a»... D #- oom (“I/80030 0m) caeupmu mo; 49 Table 7.. Summary (two year means i S.E.) of selected water chemical, physical and nutrient parameters for the Ford and Peshekee Rivers, 1988-1990. Parameter Ford River Peshekee River Conductivity 226 i 13 34 :i 3 (umho/cm) Dissolved Oxygen 10.6:t 0.4 9.9 i 0.5 (mg/L) Percent Saturation D.O. 94 i 2 87 i 1 (%) Total Alkalinity 138 i 5 15 :t 1 4mg CaCO3/L) Silicate 8.1 i 0.4 5.1 i 0.5 (mg SiOz/L) Chloride 4.8 i 0.5 0.5 i 0.05 (mg Cl/L) Total Phosphorus 50 i: 18 46 i 18 (H9 P/L) Total Nitrogen 571 i 74 559 i 68 (#9 N/L) Nitrite-N 5.2 i 0.4 6.2 i 0.6 (#9 N/L) Ammonium-N 62 i 8 67 i 9 (H9 N/L) 50 Sites UTable 8). pH values for the Peshekee River (P81 site) never dropped below 6.4, although readings as low as 4.8 have been recorded at the river’s mouth during peak spring runoff periods. Dissolved oxygen concentrations remained high year round at both sites with saturation recorded at or near 100% most of the study period (Table 7). These values also represent an instantaneous measurement of dissolved oxygen which will vary with time of day, water temperature and flow. Silica and chloride concentrations averaged higher at the F81 site than at P81 (Table 7). Chloride concentrations at F81 were much higher during September and October 1989 than they were for the same period in 1988 and 1990 (Tables A-1 and A- 2). Chloride concentrations of 9-12 mg/L, although high, are considered to be within normal ranges for this geographic region. Calcium and magnesium constitute the major cations in each stream (Figure 8, Table A-3). Of the four cations measured throughout the study, only potassium did not differ significantly (p = 0.09) between streams (Table 8). Calcium levels ranged from two to seven times higher in the Ford River than in the Peshekee, while the mean difference in magnesium was three fold. 2. Nitrogen and phosphorus parameters Two year means i standard errors of total and soluble reactive phosphorus, nitrate-N, nitrite-N, ammonium-N and 51 Table 8. Results of paired t-tests between the Ford (F81 site) and Peshekee (P81 site) Rivers for selected water chemical, physical and nutrient parameters from July, 1988 to June, 1990. Paired Parameter df t-value Probability Water Temperature 17 0.078 0.94 pH 17 17.132 0.0001 Total Hardness 17 28.669 0.0001 Calcium 11 4.314 0.001 Magnesium 11 2.990 0.01 Sodium 11 8.519 0.0001 Potassium 11 1.855 0.09 Soluble Reactive Phosphorus 17 -1.398 0.18 Nitrate 17 0.279 0.78 KM Wm ED.- 335 :ozuzeoocoo om hmmm 803< cm .56 om ma? om mg cm 25. mo OD< on 23—. mm ><2 mm mg an mm“. on #00 Cation eoncentratlons (mg/L) tor the Ford Rlver (A) and the Peshekee Rlver (B). 1988 - 1990. Figure 8. 53 total nitrogen analyses are presented in Table 7. Soluble reactive phosphorus and nitrate-N concentrations were not found to differ statistically (p < 0.05) between sites over the entire study period (Table 8). Concentrations of soluble reactive phosphorus throughout the entire period were never greater than 10 ug P/L except for October 1988 at the P81 site (Tables A1 and A-2). On a seasonal basis, mean soluble reactive phorphorus concentrations at P81 were slightly greater than those measured at F81 (Figure 9). Nitrate-N levels were similar in each stream, except for the winter seasons (Figure 10). The higher concentrations of nitrate-N found at F81 each winter are likely the result of higher deciduous leaf inputs each fall to the Ford River. Mean nitrite-N and ammonium-N concentrations were similar at both sites throughout the study period. Total nitrogen and total phosphorus values varied greatly between sites and in some cases appeared to be inaccurate (Tables A-1 and A-2). Since total nitrogen and total phosphorus concentrations represent the sum of each of their respective forms, totals should never be less than the dissolved concentrations. In this study, several total values were not greater than the dissolved forms, i.e. total phosphorus at P81 8/5/88, at FSl 7/23/88 and total nitrogen at P81 3/4/90, at F81 1/21/90 and 3/3/90. Due to technical problems in the laboratory analysis of these two parameters, results should be viewed with caution. 54 E.) I FS1 3 PSI I IIIIIIIIIIIII ('11:! on) ontoudooud Mlle"! OIQI‘IIOS 88:! :I: S.E.) In soluble Wive phosphorus at the Ford (F81 she) and Peshekee (PS1 slte) Rlvers, 1988-1990. Seasonal varlatlons (mean Flgure 9. 55 ”El \osds \ | g . § - § ' 2. (1m 61*) N-OIIJIIN Seasonal varlatlons (mean 1: S.E.) In nltrate at the Ford (F31 slte) and Peshekee (PS1 site) Rivers, 1988-1990. Flgure 10. 56 Life History 1. Life cycle Results from the length length-frequency distributions over a seven month period clearly indicate a three-year life cycle for A. lycorias (Figures 11, 12, 13, 14, 15). Nymphs ranging from 2.5 mm to 22.0 mm were collected. Emergence had already occurred at both sites before the July, 1990 sample collection, as only two peaks in the distribution were apparent (Figure 11). A few individuals who had not emerged yet were still evident in July. The merovoltine pattern as described by Pritchard (1983) became obvious when the young- of-year nymphs appeared in August, 1990 (Figure 12). Neither an egg or nymphal diapause was detected for organisms of either stream in this study. Two patterns were observed after the overall distributions of nymphs were broken down by sex. First, the mean lengths and corresponding dry weights of female nymphs of each cohort are larger than male nymphs of the same age. This trend became more pronounced as the nymphs increased in age from July, 1990 to January, 1991. Secondly, mean lengths of nymphs collected on the same date in each stream indicate that organisms of all size classes from the Peshekee River are slightly larger (Figures 12 and 13). Actual calculations of mean lengths and dry weights are presented later in this section under the heading of natural stream growth rates. Male I Female D Unknown 5'?!“ I: 173 9'83 88 9'33 9'13 13 9'03 03 9'6L GI 9'8) 8|» 9'“. LI 99) SI 9'9) Length (mm) ID V (A) (B) F 30- 10- o 30- 20- 1o~ 91 9'?) VI 9'81 81 9'81 Z) 9'” ll 9'01 IOQIDO Q G'- Nmfi'lflmh PQNQvaQonQNQm P from the Ford Rlver (A) and the Peshekee Rlver (B), 7/90. Size-frequency dlstrlbutlon by length 01A. Mtge collected Flgure 11. V3 9'83 83 9'33 9'13 )3 9'03 03 9'6) GI 9'81 D Unknown @ Male I Female 9'11 Ll 9'9) 9'9) 9t 9'71 9'81 8) 9'3) 3L 9'” 9'01 (A) F'QN F 30 20 quwnu Length (mm) (B) 30- 20- 10- qunu 9'Ll 9'91 9'9) SI 9'?l 9'8) SIze-trequency dlstrlbutlon by length of A. m collected trom the Ford Rlver (A) and the Peshekee Blver (B), 8/90. Flgure 12. 59 as» .8. as: 83.28.. 2.. as 3 as: Eon. 9.. sea 3.00:8 «stoic-a. é. .o 59.». 5 5:22.35 >oeoaooeoum .9 0.59“. L L l L l L l L IISISIWIELZLWIDLS mu .1. .9 9 ”v .8 7.. ”I 9L9999999893919096989499999798939L 8L 0 o— 8. a €958... 7a 79 7.0 7v Ir lo I) Ip Ir It 1- Ir Io Ir zezzalzoasielilelelWlslzlwleLs e 1 e s w t z w .79893919096989l99999V9893919096989L99999V98939) c or 295“. I :26:ch U is a uqumu qunu (A) 30 [j Unknown g Male I Female 20 10 Joqumu Length (mm) 60 O ,— JoquInN 0 FQNWomvmmmehmmm NOVIOCDN '— Slze-lrequency dlstrlbutlon by length of A. chorlas collected lrom the Ford River (A) and Peshekee River (3), 10/90. Flgure 14. 61 9'83 D Unknown a Male I Female Length (mm) (A) 30 20 10 0 Slze-trequency dlstrlbutlon by length at A. M collected Flgure 15. (mm the Ford Rlver (A) and Peshekee Rlver (B), 1/91. 62 2. Sex ratios Female to male ratios calculated for each size class at F81 and P81 varied by size class. Ratios ranged from 0.8:1 for second-year organisms at PS1 and F81 in July, 1990 to a ratio of 3.7:1 for third-year nymphs at FSl in July, 1990. In general, second-year class ratios at both sites were 1:1, while mean ratios for third-year class individuals increased to 2:1 at F81 and P81. 3. Diet Mean foregut fullness of young-of-year size classes in each stream depended on time of year (Figure 16). At the time of sample collection in August and October, 1990, young- of-year organisms at F81 had greater mean gut fullnesses than did those at P81. Young-of-year gut fullness dropped at both sites in January, 1991. Mean gut fullness for second-year classes in both streams was fairly consistent for all dates sampled. A large difference between gut fullness of third- year nymphs at each site occurred on the August, 1990 date. Average gut fullness of P81 individuals was 92%, while that of the F81 nymphs was only 25%. The remaining dates sampled were consistent between sites for the third-year class. Young-of-year organisms in both streams had fuller foreguts on the October, 1990 date than any other year class. Third- Proportlon Proportlon Proportlon 1.0- 0.8 '- 0.6 '- 0.4 0.2 0.0 1.0- 0.8 - 0.6 1 0.4 - 0.2 '1 0.0 - 1.0 - 0.8 d 0.6 - 0.4 ' l 0.2 '1 0.0 '- (A) El F81 PS1 Aug 89 01:89 Jan90 (B) Aug 89 Oc189 Jan90 Flgure 16. Mean gut fullness :1: S.E. A. M nymphs collected from the Ford (F81 slte) and Peshekee (PS1 slte) Rlvers; (A) Young at year, (3) Second year, (0) Third year. 64 year nymphs did the best as far as gut fullness on the January, 1991 date than did the other year classes. A. lycorias nymphs found in both streams were carnivorous as predicted by earlier studies of Actogeuria in the literature. Insect larvae found in the guts include Ephemeroptera (Heptageniidae, Baetidae, Ephemerellidae), Simuliidae, Chironomidae, Tricoptera (Hydropsychidae, Philopotamidae), Plecoptera (Perlidae, Leuctridae, Perlodidae), Odonata (Gomphidae) and Coleoptera (Elmidae) (Table 9). Organisms of most year classes on all sampling dates had detritus or unidentified organic matter in their foreguts. Ephemeropterans and Plecopterans were found in foreguts consistently from August to January. Chironomidae and Tricopterans were important diet components on the August and January sampling dates, while Simuliidae was found in foreguts of organisms from both streams in October. Rare items such as Gomphidae and Elmidae, as well as the seasonal pattern in food items, indicate that A. lyggtias is a opportunist and will eat whatever item is most available. Specific food preferences of A. lycgtias were not analyzed in this project. CW 1. Density and standing crop biomass Mean densities of A. lyggtigg nymphs at F81 ranged from 225 individuals/m2 in July, 1988 to 26 nymphs/m2 in December, x x x x .a ooxmzmoa x x x .m oboe ox. oum x x x .m ooxoomoa x x .m once as new x .m ooxocmom x X .m Uuom MON Hm\mH\H x x .m omxonnoa X X X 5m Uuom Hxfl UHm x .m ooxocmom x x .m upon as com x .m ooxooooa x .m once so» om\mH\OH s. x x x x .m ooxonmoa 6 x x .m 28 a Em x x x .m ooxocmom x x x .m once “a com x x .m moxosnom x x .m once so» om\HH\m 6 ¢ 0 my .uv am a. mu xv %. 9 do one» »»oao mono or. 06 doo do ooo AM 04 and» OD bf 69 9 IO 0) V P a \Y 5 OJ. 00 O Illl 9 .uoom mo mono» I we» .Hm\ma\a one om\ma\oa .om\HH\m .muo>em moxonmom ocm ouch one we made»: udHquNdIId mo mucoucoo usu .m canoe 66 1988 (Table 10, Figure 17). Densities for the P81 site ranged from 125 nymphs/m2 in July, 1988 to 4 organisms/m2 in March, 1989. Mean density for the F81 site over the two year period was 100 individuals/m2 compared to 40 organisms/m2 at P81, or 2.5 times more abundant in the hard water stream. Mean dry weight biomass varied between 2.66 g/m2 and 0.38 g/m2 at F81, and between 0.98 g/m2 and 0.01 g/m2 at P81 during 1988, 1989 and 1990 (Table 11, Figure 17). Mean biomass over the two year period was 1.52 g/m2 at FSl compared to 0.31 g/m2 at P81. This represented a 4.9 fold difference between sites. Differences between sites for untransformed density and biomass data were compared using paired t-tests (Table 12). Yearly and two year comparisons between F81 and P81 for both parameters all were significant at p < 0.05 or less. Paired t-test comparisons between replicate sites for each stream indicate that no significant differences for density and standing crop biomass occurred (Table 13). The general pattern of peak density and biomass during summer months was evident at both sites for the two year period (Figure 17). Numbers and dry weights dropped in the fall and spring months, with a secondary peak occurring during winter. In some cases the monthly sampling regime did not reflect true densities and standing crop biomass for that entire month. Sampling was always constrained by the limits of the Hess sampler. Therefore, a disturbance such as a 67 Table 10. Mean densities (no.ind./m2) :l: S.E. of A. m collected from the Ford (F81) and Peshekee (P31) Rivers from June, 1988 to June, 1990. N in parentheses. Density Ford River Peshekee River Date (FSl) (P81) 7/88 225 :I: 14 (6) 125 :t 10 (6) 8/88 74 i 7 (6) 21 i 2 (6) 9/88 ---- 11 :1: 2 (6) 12/88 26 i 3 (6) 21 :t 3 (6) 2/89 28 i 5 (6) 23 :t 2 (6) 3/89 44 i 8 (6) 4 :t 1 (6) 5/89 68 :l: 7 (6) ---- 6/89 45 :t: 4 (6) 21 :t 3 (6) Mean 88-89 74 i 31 (6) 36 i 18 (6) 7/89 167 :l: 15 (6) 44 :t 5 (6) 8/89 183 i 8 (6) 87 :1: '7 (6) 9/89 130 :l: 10 (6) 72 :t 5 (6) 10/89 100 :t 8 (6) 36 :I: 4 (6) 12/89 114 :t 7 (6) 42 :1: 12 (6) 1/90 144 i 14 (6) 17 :1: 2 (6) 3/90 70 :I: 8 (6) 30 :l: 5 (6) 4/90 83 :I: 5 (6) ---‘ 6/90 49 :t 4 (6) 13 :t 2 (6) Mean 89-90 120 i 19 (8) 42 :1: 9 (8) Mean 88-90 100 :t 17 (14) 40 :1: 9 (14) 68 C] Ford R. Peshekee R. (A) cm 23—. cm En? 8 «22 I oo 25. LIIIEE. some Inllfl mo POO llafl. 8 $5 1.3 8 03 I a 8 5.. mar/I. am 22. on ><2 an E! mm mm... 8 Own r. we .Ewm on .55 no 22. 300-1 3.565 3.2.8 (B) LHIIHM 822. a [Ila E om mm< cm 52 cm 23. an own mm #00 mo mwm mo 03< L 232. 1'1 0'1 fl —. ow 2:5 mm ><2 an S2 Tl-IIIL gmmm 1 mo 80 mo .Emm an 42. . 1E5... 2 cl 6.58 29.3 an 0 collected irom the Ford (F31 site) and Peshekee (P81 site) Figure 17. Densities (A) and dry weight biomass (B) :l: S.E. of A. m Rivers, 1988-1990. 69 Table 11. Mean biomass (g dry wt./m2) i S.E. of A, lycgzias collected from the Ford (F81) and Peshekee (PSl) Rivers from June, 1988 to June, 1990. N in parentheses. Biomass Ford River Peshekee River Date (FSl) (P81) 7/88 1.51 i 0.06 (6) 0.98 i 0.17 (6) 8/88 1.89 i 0.22 (6) 0.12 i 0.03 (6) 9/88 ---- 0.14 i 0.04 (6) 12/88 0.89 i 0.16 (6) 0.15 i 0.04 (6) 2/89 1.10 i 0.20 (6) 0.05 i 0.01 (6) 3/89 1.24 i 0.21 (6) 0.01 i 0.00 (6) 5/89 1.30 i 0.26 (6) ---- 6/89 0.38 i 0.04 (6) 0.13 i 0.01 (6) Mean 88-89 1.17 i 0.21 (6) 0.24 i 0.15 (6) 7/89 1.38 i 0.15 (6) 0.34 i 0.06 (6) 8/89 2.50 i 0.27 (6) 0.65 i 0.10 (6) 9/89 2.66 i 0.27 (6) 0.63 i 0.10 (6) 10/89 1.14 i 0.31 (6) 0.47 i 0.07 (6) 12/89 2.30 i 0.22 (6) 0.35 i 0.09 (6) 1/90 2.39 i 0.22 (6) 0.05 i 0.01 (6) 3/90 1.01 i 0.20 (6) 0.24 i 0.04 (6) 4/90 1.98 i 0.21 (6) ---- 6/90 0.96 i 0.15 (6) 0.13 i 0.04 (6) Mean 89—90 1.79 t 0.26 (8) 0.36 i 0.08 (8) Mean 88-90 1.52 i 0.19 (14) 0.31 i 0.08 (14) moo.o moo.e n ommalmmma mmoeofin HMOfiooHoom Hoo.o moo.» ma ommalwmma Hoo.o mmo.m n ommalmmma Ho.o mH~.v m mmmalmmma mmmEon Hoo.o neo.m b ommaimmma 0 aufimcoo HooaooHoom 7 Hoo.o «ms.m ma ommasmmma Hoo.o Ham.o b ommaimmma mo.o mao.m m mmmalmmma >uflmcoo no.0 A a u mz 2597p mo nouosmumm auwHfinmnoum ooufimm .omma .ocso ou mama .mcoo Eoum mmmeofin coo mufimooo udHHGUNH .d How Aawmv uo>am moxonmom ocm Aammv uo>wm ouom one ooozuon mummulu panama mo muaomom .NH magma Amman .uusm xoou NE\mV m2 m2 mmmEon HooaooHoom ANE\OV wz mz momsofim mouu masocmum Amoum .MMSm xoou ~E\.ocv m2 m2 muflmcoo HoOflmoHoom m2 m2 ANE\.OGV mufimcoo Nmm .m> Hmm Nmm .m> Hmm Houosoumm no.0 A o u mz muflafiomooum .mwma .aaso .muo>fim ooxocmom com chow may canoe: moufim oumofiamou um momeoflo mono ocflocmum poo mofiuwmcoo udfluduud .4 mo mumouuu ooufimm mo muasmom .mH manna 72 Imajor'discharge event would postpone sampling to a later date at which time populations could have differed from pre-flood conditions. Also, density and standing crop values obtained at certain points in the life history such as emergence and the hatching of nymphs were influenced by the sampling regime. Ecological or effective habitat densities (number of individuals/rock surface area) and biomass standing crop values (biomass/rock surface area) (Resh, 1979) were calculated for each riffle due to possible differences in substrate types between the sites. Regressions between known rock surface areas and the product of long and short axis circumferences were calculated for PSl (y = 1.695 + 0.384x, r2 = 0.99; y = rock surface area, x = product of circumferences) and F81 (y = -2.195 + 0.394x, r2 = 0.98) to determine rock surface areas for each sample. Mean differences between sites over the two year period for ecological density and ecological biomass were similar (2.6 and 4.8-fold differences, respectively) to the density and biomass calculations based on stream bottom area (Tables 14 and 15). The pattern of ecological density and biomass at each site for the period from June, 1989 to March, 1990 paralleled the patterns observed earlier (Figure 18). Ecological density and biomass differed significantly, p < 0.001 and p < 0.005 respectively, between sites for the period between June, 1989 and March, 1990 (Table 12). No 73 Table 14. Mean ecological densities (no.ind./m2 rock surface area) i S.E. of A. lxcorias collected from the Ford (F81) and Peshekee (PS1) Rivers from June, 1988 to June, 1990. N in parentheses. Ecological Density Ford River Peshekee River Date (F81) (PS1) 6/89 27 :i: 1 (6) 7 :1: 1 (6) 7/89 61 :l: 6 (6) 19 i 3 (6) 8/89 61 :1: 3 (6) 31 i 2 (6) 9/89 59 i 3 (6) 28 i- 1 (6) 10/89 50 i 5 (6) 27 :i: 5 (6) 12/89 58 :t 2 (6) 13 i 3 (6) 1/90 57 i 6 (6) 18 2t 3 (6) 3/90 31:i 3 (6) 13 i 3 (6) Mean 89-90 51 :i: 5 (7) 20 :i: 3 (7) Table 15. Mean ecological biomass (g dry wt./m2 rock surface area) i S.E. of A. lycorias collected from the Ford (F81) and Peshekee (PSI) Rivers from June, June, 1990. N in parentheses. Ford River Ecological Biomass Peshekee River Date (F81) (P81) 6/89 0.25 i 0.02 (6) 0.05 i 0.01 (6) 7/89 0.53 i 0.06 (6) 0.16 i 0.03 (6) 8/89 0.85 i 0.10 (6) 0.22 i 0.03 (6) 9/89 1.10 i 0.12 (6) 0.26 i 0.04 (6) 10/89 0.47 i 0.08 (6) 0.26 i 0.04 (6) 12/89 1.20 i 0.09 (6) 0.12 i 0.03 (6) 1/90 0.98 i 0.08 (6) 0.04 i 0.01 (6) 3/90 0.40 i 0.06 (6) 0.09 i 0.02 (6) Mean 89-90 0.72 i 0.12 (7) 0.15 i 0.03 (7) Density (noJm2 rock area) Biomass (glm2 rock area) 75 70 - (A) D Ford R. 60 - FT— ; Er- FL ’1‘ Peshekee R. 50 -( 40- 30 20 10 JUN 89 JUL 89 AUG 89 SEP 89 OCT 89 DEC 89 JAN 90 MAR 90 1.4- (B) l r1 :3 g F 0.6 " 0.4 - 0.2 0.0 3 Figure 18. Ecological densities (A) and ecological biomass (B) i S.E. of A. um; collected from the Ford (F81 site) and Peshekee (P81 site) Rivers, 1989-1990. JUL 89 was s: OMS; SEP 89 OCT 89 85: g; 76 Significant differences occurred between replicate sites for ecological density or biomass values (Table 13). 2. Annual production estimates Mean annual production of A. lyggrias corrected with a CPI factor of 0.333 at PS1 between 1988 and 1990 was 0.43 g dry weight m'2 (Table 16, Figure 19). For the same time period, mean annual production at FSl was 2.18 g dry weight m'z, or 5.0 times the amount calculated at P81. Production estimates at P81 were slightly higher from 1988-1989 than from 1989-1990. At FSl production estimates for 5.;ycogias were greater from 1989-1990. Annual production estimates were calculated from standing stock biomass and biomass turnover rates (Benke, 1984). Mean annual P/B ratios over the two year period were similar; 1.42 yr‘1 for F81 and 1.58 yr'1 for PSl (Table 16). Differences in production estimates between sites, therefore, were the result of differences in standing crop biomass. Mean annual total biomass at F81 was 1.54 g dry weight m'2 (Tables B-1 and B-2). At the soft water site, mean annual total biomass was 5.5 times less, averaging 0.28 g dry weight m'2 (Tables B-3 and B-4). The difference in biomass standing crop between sites accounted for the large difference in production estimates. 77 whee» em.o H mm.H ce.o H ce.e «0.0 H me.o .m.m H cam: mmumc mm.H co.e me.o camaummmfl meumc mm.H ee.m He.o mmmelmmmfi .HHumHIHuHHquumunuum momma «0.0 H ~c.a HH.o H e~.e ev.o H mH.m .m.m H see: mmucc mm.a mH.e Ne.~ cmmfiummma emcee me.H em.e me.H mmmaummmfi z AH>\HV ANE\ov m\m m\m coHuosooum Hooded uuonoo Hmuoa .ommfllmmma coo mmmfilmmmfl How conuoe mucosvoHMIouHm on» mchs ooumaooamo Hmm poo Hmm um udfluduud_.d mo coHuooooum Hmscq< .oH canoe 78 .8282 ES. .5... .2... 8.2.8.. .2... $9.. .2... Be“. 2.. 88.8.2. .m .c 58.52.. .255. .2 2:2“. ooém Home: an. x .m“. D ooém mm-mm rm (JR/alum Mp Ii) uononpoad 79 Further analysis of the production data yielded differences in annual density and biomass standing crop among the year classes. Nymphs were divided into age classes based on total length; young-of-year = 0-6 mm, second year = 7-12 mm, third year = 12-25 mm. Total annual density or biomass for each age class was calculated and plotted (Figure 20). The young-of-year class made up the largest proportion of total nymphs per square meter per year at each site, but contributed only a minor portion of the total biomass per square meter per year. The third year class made up a substantial portion of total annual biomass and production in each stream. Growth Rates 1. Natural stream growth rates Mean dry weights of each year class of A. lyggrias collected on each sampling date between August, 1990 and January, 1991 were calculated from length/weight regressions (Figure 3). Standard errors associated with length measurements and the dry weights were less than 0.05 mg (Table 17). A plot of mean dry weights revealed two trends in the data (Figure 21). First, female nymphs of the second and third year classes weighed more than the male nymphs of their corresponding classes. This difference in weight between the sexes increased with age. Secondly, with the 8,, _ (A) E] Ford R. E Peshekee R. Ii T: 30 .. s s 9 E g T c E 40 " c .. “ d — C s v .2 20 - 0 -l YOY 2nd yr 3rd yr YOY 2nd yr 3rd yr 1988-1989 1989-1990 2.0 (B) 8 E 7: 1 5 2 5‘ ' n s 3 '5 g g 1.0 < 'u 3 9; ,2 0.5 0.0 YOY 2nd yr 3rd yr YOY 2nd yr 3rd yr 19884989 1989-1990 5 r 81 (c) '6 1% i 3 z e 6- < E T- g 2 ‘ ‘6 . '— 0 _ VII/I YOY 2nd yr 3rd yr YOY 2nd yr 3rd yr 1988-1989 1989-1990 Figure 20. Total annual _A. chorlas densities (A), dry weight biomass (B), and production (C) by year class for 1988-1989 and 1989-1990. .FH. o.o H m.cm .vH. o.c H H.om .am. o.o H o.HH .HN. o.o H o.m .mp. c.o H m.H Hmm .mH. o.o H «.mw .HH. c.o H o.mm .ca. 0.0 H N.MH .HH. o.o H m.s .wp. o.o H c.H Hmm Hm\mH\H .Hm. c.o H m.mm .vH. o.o H m.m~ .mu. o.o H H.eH .mm. 0.9 H c.e .we. c.o H p.H Hmm .cc. o.e H e.Hm .eH. o.o H c.m~ .HN. c.c H m.~H .vm. o.o H m.o .oe. o.o H n.c Hmm om\mH\OH .cm. o.o H H.mc .mH. o.o H H.o~ .mv. o.o H p.oa .mm. o.o H p.» .mm. e.o H m.H Hmm .pm. o.o H m.mc .HN. o.o H «.mm .Hq. c.o H m.a .mm. o.o H H.u .mc. 0.0 H m.c Hmm cm\m\mc 1 .mm. o.e H m.om .vm. o.o H o.e~ .Nv. o.o H m.m .Hv. e.o H «.8 .mH. o.o H >.c Ham 8 .mv. o.o H c.ce .NN. o.o H m.m~ .Nm. c.o H ~.a .co. 0.0 H c.w .cm. o.o H m.o Hmm om\HH\o .Nm. o.o H H.ee .em. 0.0 H m.- .He. c.o H >.w .mc. o.o H >.m :1. Hum .mu. 0.0 H H.cm .c. o.o H v.H~ .ce. o.o H m.c .Nm. o.o H o.c nu- Hmm ea\m\h m _ z m _ z ouHm wumo new» cum new» new so» .nwnonucouma GH 2 .mHmem n m .oaoz n z .nnmao new» ouHaa n m .nnmao Moo» ocooom n N .umo>ruoumcoow I No» .HmmH\H r omma\h .Hmm use How um oouooaaoo ddduduad .d mo unmao away an .m.m H Ame. unmfiw: hub coo: .bH wanna 82 [3 Ford R. I Pesh R ) A ( «4:414- uu—u-1q da- 8642086M20 1mmmmmo 00 moonoommmm 0000000000 .3 ...s so :3... Sept 90 Oct 90 Jan 91 Aug 90 s as.“ Sdbm bmae a.uM F MFRR Rahh. 3 mm“... FPP UfifimNew/Aumnfiwwnw/fiw/flfiammfinew.“ ................................................. ) B ( 11H......<.‘..... 6 0 m H w. m m o m a o 0. 0. O. 0 0. O. D 0. D o o o o o 0 O o o .3 .3. so :8: Aug 90 Sept 90 Oct 90 Jan 91 July 90 m) H“Hamwfiwflwflw//¢//,/flwfl%fl .fiwmwwwwfluMW/fi/Afi/flAAV/A .......................................... ......................................... 0.07 - 006'- 005- 0.04-I coal 002- .3 .5. to :8: Aug 90 Sept 90 Oct 90 Jan 91 July 90 Figure 21. Mean dry weight :1: s. E. by month of young-ot-year (A). second year (B) and third year (C) A. lycorias nymphs collected from the Ford and Peshekee Rivers. 7/90-1 I91. 83 enmception of the January date, nymphs of all year classes from the Peshekee River were larger. Monthly growth rates for young-of-year nymphs at both sites were greater than rates of older nymphs (Table 18, Figure 22). Young-of-year nymphs from PSl grew at a faster rate throughout the fall than did their counterparts at FSl. Between the months of October and January, young-of-year nymphs at FSl grew at a slightly faster rate. Some cases of negative growth rates occurred in the data set. Negative growth rates resulted for months where mean weights for a year class did not increase from the previous month. These negative rates are likely the result of sampling biases or the loss of larger, heavier individuals from the population between successive sample collections. Growth patterns varied by month and by sex for older nymphs living in each stream. Second and third year female nymphs at FSl at each site grew faster than male nymphs (Table 18, Figure 22). Growth rates of third year male and female nymphs dropped drastically at both sites between August and September, but rates for second year nymphs differed only slightly between sites for the same time period. Nymphs of both sexes from the PSI site exhibited zero or negative growth for the October to January period, similar to the growth pattern of young-of-year nymphs described above. one. o.~ H oooof mum o... H mooo. onm o... H 38.: o... o4 H 38.. mum o4 H 88.: How mum o6 H «moo. on... o4 H :8. oum o... H oooo. mum o4 H 38. one. oA H oooo. Hmm 88H: mum o.¢ H mmoo. mum o.m H omoo. mum o.m H oooo. mum o.H H oooo. mum o.H H oHoo. Hum mum o.o H Nvoo. mum o.N H «moo. mum o.m H omoo. mum o.N H oHoo. o.o H Hmoo.u Hmm om\wa\ofl 4. 8 ml... o.~ H 38.: on”. o... H mooo. mum o... H 2.8. min o4 H omoo. mum o.~ H ommo. Hmm mum o.o H omoo.u wlm o.m H Hmoo.| mum o.~ H oHoo. mum o.H H mooo. mum o.~ H mono. Hmm oo\m\o mum m.~ H ocoo. on... o.m H mcoo. one o... H «coo. mum «A H omoo. ii Hon. on... HA H 88. one o.~ H «moo. mum m4 H oomo. on... Q; H 58. in- am... 821.. m _ z m _ z 33 33 new» cum use» can Mow .wamfiwh u h .0HM2 I z .nnmao Hook UHHna n m .namao new» ocooow u N .Hmoalwonmcoow I No» .HmmH\H : ooma\o .Hmm can How an oouuwaaoo udduduud .4 mo nomad How» an .m.m H .thno. noumu nusoum hanucoz .oa wanna 85 A 0.04- ( ) g a E O E S E 2 0 -0.01 . . Sept 90 Oct 90 Jan 91 o 03 _ (B) C] Ford R. Males D Ford R. Females ; ‘ I Pesh. R. Males G g 0.02 _ - Pesh. R. Females O E .B E 2 0 -o.o1 . . . a Aug 90 Sept 90 Oct 90 Jan 91 9 C E O E 8 S 2 (5 -0.01 . . . fi. Aug 90 Sept 90 Oct 90 Jan 91 Figure 22. Monthly growth rates :1: S.E. ot young-ot-year (A). second year (B), and third year (C) classes of A. tycorIas collected from the Ford and Peshekee Rivers. 8/90-1/91. 86 Statistical analyses of monthly growth rates were not possible, since rates were calculated from monthly mean weights rather than individual weights. Although growth patterns of nymphs differed between sites from one month to the next, the difference in magnitude of growth rates between sites for the entire sampling period was not greater than expected. 2. Laboratory stream growth experiment The pH, conductivity, alkalinity, and hardness of the streamwater of the soft water and hard water treatments reflected typical water chemistry of the natural streams during low flow conditions (Table 19). The six-fold difference in hardness between the two streams provided a good contrast in water chemistries to test the hypothesis of increased growth rates with increased water hardness. Mean dissolved oxygen concentrations maintained in each stream were high (9.2 mg/L). Even though the temperature controls were set at 15° C for both streams, there was a slight difference in mean water temperature between streams. Water in the soft water treatment averaged 0.5° C warmer than in the hard water treatment. A min-max thermometer in each stream recorded temperatures between 12° C and 16° C. Since growth is affected by water temperature, growth rates could have been biased in favor of the organisms living in the soft water stream. 87 .0 0mm ou oouoounoo none: H .q\mo me. oz .m.o-o.o. e.o H o.o .o.ono.o. o.o H o.o cmosxo .mch .q\moomo o5. Hoo.o v o .omlofi. N H em .oofllomfl. o H mes monsoon: .q\moomo ms. Hoo.o v o .oNIoH. N H ea .ccflnooe. o H NNH suHcHmeHa .moce:.. Hoo.o v o .omimm. o H em .oomumfim. eH H com HuH>Huocccoo Hoo.o v o .m.olfi.o. H.o H v.2 .c.oum.o. o.o H e.o mo AUOV oz .o.ofiuo.NH. o.o H m.eH .o.oHlo.~H. o.o H o.oa mucomumosoe no.0 A a n mz H0>Hm ooxocmom H0>Hm ouom HouoEmumm oocmoHuHcon ummulu monsom Houmz .momonuconmm CH cocoa ..m.m H one: .ommH .uonouoo ou mono Eouu omuosocoo monum cusouo auououonma Mdfiuduad .d mo mucoEumoHu nouns HHOm can onmc no moHumHuouomuoco Hmonch one HmoHEoso .mH wanna 88 Mortality rates for the duration of the experiment were lower than mortality rates experienced during previous attempts to rear A; lycorias nymphs in the laboratory. Three percent of the Ford River nymphs died and 20% of the Peshekee River organisms were lost in the hard water treatment. Twenty-three percent of organisms from both streams died or escaped in the soft water treatment. Nymphs lost during the experiment were not replaced with new organisms. Individual growth rates were measured under conditions of unlimited space and food in the laboratory environment. A log plot of mean weights of each group of organisms by treatment and sex at time zero, day 41 and day 110 demonstrates that growth approximated a straight line or constant rate over the experimental period (Figure 23). Therefore, individual laboratory growth rates over the 110 day period of A.lycorias nymphs may be described using the instanteous growth equation. Hartley’s test for homogeneity of variances of mean growth rates was non-significant at the 0.05 level. Untransformed data were analyzed using 2 x 2 x 2 unbalanced form of analysis of variance. Nymphs taken from both the Ford and Peshekee Rivers grew at a slightly faster rate in the high hardness water than in low hardness (Table 20, Figure 24). Organisms originally from the Peshekee River grew at a slightly faster rate than Ford River nymphs regardless of water hardness. Results from the analysis of 89 .Eofitonxo 5265 E823... .0 5.3.2.8 new 2.8.2:. .2...» s .m .o z. .5an.. 9... .E 3 no 59.». .E ..o .2. new 3 2.9.5.. .3229: .o .m.mH 2:92.. no. :92: .2 959... 7...... 2...... c: we 0 - win. IIIII IE“. IIII min— IInTI. IE". IT wk. 2 1| IE2 IT mi: '0': TE... IT W w (6) tum-M 601 90 Table 20. Mean A. ignoring laboratory growth rates (day'l) for 110 day period i S.E. in soft (20 mg CaCO3/L) and hard (135 mg CaCO3/L) water treatments. N in parentheses. Water Hardness 20 mg CaCO3/L 135 mg CaCO3/L Peshekee River Male .0061 .0006 (14) .0060 .0004 (14) Female .0063 .0007 (15) .0070 .0007 (13) Mean .0062 .0006 (29) .0064 .0004 (27) Ford River Male .0058 .0006 (20) .0056 .0004 (20) Female .0062 .0008 (9) .0073 .0008 (10) Mean .0059 .0005 (29) .0061 .0004 (30) 91 68.. oz. .2 2.3..» >353... ... no.8. 29...... 2......2 ... can. .Ieln m..d...>2.m...oon. Inell . auteu— ..<.. 0.2-.2 0.3 0.05 .0 n38 530.3 2002 .cu 0.59...— ....808 o.o. 88...... .32... 3...... 8 s so... om. no... so. . . meooo . 88o - 88o fin wooed (hp/t) om mums 92 variance calculated from growth data after 110 days indicate that no significant (p < 0.05) differences in growth existed in this experiment (Table 21). Probabilities of the three- factor and two-factor interactions were all highly non- significant. Of the strain, sex and treatment factors, only sex was relatively important in explaining the variance (Table 21). After separating growth data by sex of the nymphs, it became apparent that only the female nymphs grew faster in the hard water treatment (Table 20, Figure 25). Males of both strains grew at nearly equal rates in either treatment (Table 20, Figure 25). Female nymphs of both strains grew at faster rates than male nymphs. oim Hm.m elm «o.o coH HoHHm Ne.o mH.o elm oo.o Hum oo.o H 0mm m~.o me.H elm om.e elm om.e H on Ho.o e~.o elm He.H o-o He.H H om Ho.o oN.o elm om.H elm om.H H .o. “coaummuo % oo.o oH.o o-o mo.H elm No.H H mm Ho.o Ne.m mum Ho.H mum Ho.H H .m. xom mm.o om.o elm mo.H oum oo.H H .a. chuum HHHHHanon m m: mm Ho moucom .mucoaouommoe nusoum Hmch co comma ¢>oz¢ .ucwEHHono Emonum muoumuonma m cH nuzoum “MHHdUNd .4 so oUGMHHm> mo mHm>Hmcm poocmamncs Houomw oouau Mo muHSmom .HN manna 94 0.0085 - (A) —.— Posh. R. Nymphs H. —1n— Ford R. Nymphs >~ G '13 0.0075 - O E 5 0.0065 - i 2 0 0.0055 - 0.0045 . r Low High (20 mg/L) (135 mg/L) Water hardness (mg oacoa/L) 0.0085 - (3) “>7 1:: 0.0075 - o I ‘5 I = 0.0065 - T E 2 0 o.m55 . H 0.0045 1 u Low High (20 ins/L) (135 mall) Water Hardness (mg CacoalL) Figure 25. Mean growth rates of female (A) and male (B) A. chorlas nymphs reared in laboratory streams tor 1 10 days. DISCUSSION The first objective of this study was to compare and contrast physical and chemical characteristics of stream water at the Ford and Peshekee River sites. Values obtained for conductivity, pH, total alkalinity, total hardness and cation concentrations varied significantly, as expected, between the two study sites. Water temperatures and dissolved oxygen concentrations, although not monitored on a continuous basis, varied only slightly between sites over the course of the study. Current velocities within each study riffle were similar at sample collection times. Discharge data, climatic data and personal observations of discharge response at each site provided some evidence that large snowpack runoff, topography and soil type contributed to a more variable, less stable flow regime at P81. Future work at these two sites will require a closer examination of differences in flow regimes within each stream. Both streams were relatively nutrient-poor. Mean orthophosphorus and nitrate concentrations were similar between sites over the two year period. Burton et. a1. (1991) reported higher orthophosphorus and nitrate concentrations along a continuum in the Peshekee River as compared to the Ford River. These data reflected nutrient levels during the month of August only. Data collected thoughout the year from 1988 to 1990 in 95 96 the present study suggested that no mean differences existed with regard to nutrient availability. However, seasonal variability in nutrient concentrations between sites did occur and might have influenced primary productivity during certain seasons of the year. Substrate composition was described at the F81 and P51 sites only. The substrate was predominately cobble at both sites which was one of the criteria examined when site selection took place. However, substrate composition at the sites may not necessarily reflect that of the entire stream channel. Although substrate composition along the stream continuum was not quantified, personal observations indicated that large areas of cobble substrate were common along fourth-order sections of the Peshekee River. In contrast, a greater portion of the Ford River consists of sand substrate, a poor habitat for most invertebrates. Other factors that would play an important role in invertebrate distribution and were not considered in this study include substrate stability, heterogeneity, texture and pore size (Minshall, 1984). Riparian vegetation surveys suggested that immediate vegetation surrounding FSl was dominated by deciduous species, while coniferous species were more common at P81. Terrestrial vegetation, like substrate, varied along a continuum at each river. A complete riparian survey has not been conducted for either stream. Differences betwen the 97 Ford and Peshekee Rivers along this continuum would be expected to influence invertebrate densities downstream in the form of differential allochthonous inputs, shading and dissolved organic material concentrations. Life history characteristics such as nymphal development length and emergence periods of A. lycorias living in each stream were similar to those reported in the literature for other Acroneuria species. The three-year life cycle reported by Peckarsky (1979) and Barton (1980) was consistent with data collected for A. lycorias in this study. This three- year cycle is one year longer than those found for Acroneuria species observed in California and West Virginia (Heiman and Knight, 1975; Schmidt and Tarter, 1985). Emergence was observed for A. lycorias during growth studies in the laboratory, but not at either field site. Narf and Hilsenhoff (1974) mentioned difficulties in collecting emerging A. lycorias nymphs in the field. It is assumed that the emergence period in the present study was extremely short, synchronous and occurred sometime between May and July, the months of final presence of mature nymphs and first appearance of young-of-year nymphs. The switch from a 1:1 sex ratio to a 2:1 ratio favoring mature female nymphs may be related to some unknown mortality factor following the second year. The deviation in sex ratios has not been reported in the literature before for A. lycorias nymphs and will require more research to fully explain the observed ratios. 98 The pattern of greater mean weights of female nymphs over male nymphs in both stream is not unusual. Sexual dimorphism in size has been documented in the literature (Pritchard, 1976; Sweeney, 1978; Vannote and Sweeney, 1980). In most cases, the extra weight achieved by female nymphs is associated with eggs in the abdomen (Butler, 1984), but data from the present study indicated that this sexual dimorphism in size appeared early in nymphal development. Butler (1982) offered one hypothesis based on studies with Chironomus that male nymphs stop feeding and growing much earlier than female nymphs do, but still continue with development. This hypothesis was not supported by foregut content data of A. lycorias of the Ford and Peshekee Rivers. All third-year nymphs, male and female, contained prey items of some sort during the month of January, only four months before emergence. The fact that nymphs of all size classes collected from the soft water stream were slightly larger in size than hard water organisms is important in that positive correlations between size and fecundity has been reported in the literature (Sweeney and Vannote, 1981). Implications of the size/fecundity correlation to this study suggest that mature female nymphs of the Peshekee River could produce more eggs per adult nymph than those nymphs reproducing in the Ford River. In theory, potential recruitment per individual female nymph is greater in the Peshekee River. Overall 99 recruitment, however, is probably balanced by the fact that fewer mature nymphs exist within the Peshekee River population. Unfortunately, fecundity data is not available to support or refute this idea. Food items found in the foreguts of A. Aygggigg collected from the Ford and Peshekee Rivers were very similar to diets reported for other species of Agrgnguria collected within North America (Heiman and Knight, 1975; Shapas and Hilsenhoff, 1976; Johnson, 1981; Schmidt and Tarter, 1985). Additionally, the types of prey items taken by A. lyggrigg in each stream were similar for each of the size classes. Although prey availabity and selectivity was not examimed, seasonal trends in foregut contents indicated that the diets of A. lycorias nymphs, like the Acroneuria nymphs studied by Sheldon (1969) and Siegfried and Knight (1976a), were quite flexible. By having diets which can vary with changes in prey densities, A. lycorias nymphs were able to maintain mean gut fullnesses of at least 25%. The exception to this was observed in the month of January when young-of-year nymphs at both sites, the largest size class by numbers, were found to have empty to near empty foreguts. One of the hypotheses for lower productivity in soft water rivers was described in the introduction as being food quantity or quality related. Two studies, one conducted in the Ford and Peshekee River watersheds and the other in New Zealand streams, suggested that this may indeed be a valid 100 'hypothesis. Burton et. al. (1991) found that diatom densities and chlorophyll A standing crops were greater at sites along the Ford River than along the Peshekee River, suggesting that the algal food base is stronger during the month of August in the hard water stream. Data from separate unpublished studies by T. M. Burton and R. J. Stout at unrelated sites at the Ford and Peshekee Rivers in July, 1985 indicate that A. lycorias prey densities were similar at both sites (Table 22). Prey/predator ratios (prey items available to each size class of A. lycorias divided by the number of A. lycorias nymphs of each size class) were very different however, because of the low A. lycogias densities found in the soft water stream. In a set of New Zealand hard and soft water streams, Collier and Winterbourn (1990) concluded that higher grazing rates by Qeleatidium reflected lower quality of epilithic food in the soft water streams. Clearly, the question regarding food quality or quantity differences between the Ford and Peshekee Rivers for the various trophic levels will require further research. The second objective of this research was to estimate as accurately as possible, the annual production of A. lycorias nymphs in each study stream. At the start of the study, I predicted as an alternate hypothesis that annual A. lygorias production would be positively related to stream water hardness. Greater production should be found in the Ford River than in the Peshekee River. This prediction was true 101 .mwmo mm How ooNHcoHoo on ow oesoHHm mums coHns oumuumnsm nqu ooHHHu muoxmmn HoocHHwOImHmc 60 onmmme mo ooumHmcoo moHdEom HH4H .mmmH .couuom .2 .9 >9 mooHHm uooua onEHoooz um oouooHHoo mpoo Ho>Hm moonmomN .mmma .usoum .o .m wn xmm um oouooaaoo mumo Ho>Hm ouomfi o.~mom N.o H o.o o.mmH m.mooa Hoow oum o.omm o.o H o.m m.mmH o.oooH Homw com o.omH o.H H o.o o.ova o.on wow 3% o.omoH m.o H o.o o.omH N.>N¢H Hoow cum m.mmHH m.o H ~.H o.omH N.omva Hoow com o.mo H.~ H o.oH m.ooH o.moHH wow a oHumm .oHdEom\.ocv Hoaosom\.oc. mmoau Hmow Houmoonm\woum ddHHduwH;4 mEoHH woum .umowlmolmcsow n wow .ddduduwd .4." Houmooum .mmoHHHsEHm can .omoHnomonuowm .oooHHcoomuoo: .omoHEocouHco n mEmHH woum .muo>Hm Nooxonmom one Houom on» How uufluduwd .4 mo mmmHo ouHm wn moHuoH Houmoouo\woud can .m.m H .HoHaEmm\.oc. moHuHmcoo Houoooud can wand coo: .Nm canoe .mmma\ma\b 102 for: the period between 1988 and 1990 at the Ford and Peshekee River sites. Mean annual production of A. lyggrigg was 5.6 times greater at the F81 site than at the PS1 site. The difference in standing crop biomass between sites, rather than biomass turnover was the major factor responsible for the observed production estimates. The difference in production levels of a stream invertebrate between the Ford and Peshekee Rivers is higher than those reported in several other studies of this kind. Krueger and Waters (1983) reported a 2.3 fold difference in annual production by invertebrate carnivores and a 4.4 fold difference in herbivore-detritivore production in a hard and soft water stream. They presented production values for an Acrgneuria species found in the Blackhoof River (mean alkalinity = 83 mg CaCO3/L) of 0.2 g/m2 as wet mass. This value was less than dry weight production values obtained for the Peshekee River with a mean alkalinity of 14 mg CaCO3/L. The Acrgnegria species was not present in the other two Minnesota streams studied by Krueger and Waters, so correlations between stream water hardness and Acroneuria production could not be made. Annual production of Deleatidium larvae was 4.2 times greater in an alkaline stream than in an acid stream (Collier and Winterbourn, 1990). Results from their study also reflected higher standing crop biomass in the alkaline sites, with relatively constant P/B ratios across all sites. Populations of 103 Exaleatidigm at the least productive sites were characterized as having very few late larval instars, a pattern similar to that found for the A. lycgrias population structure at the Ford and Peshekee River sites. The study’s third objective was to determine natural stream growth rates of A. lygorias nymphs in hard and soft water as well as growth rates under controlled conditions in the laboratory at high and low water hardnesses. Growth rates were expected to be lower for organisms living in the soft water stream and the low hardness laboratory stream, since low cation concentrations would require the nymphs to divert more energy towards osmoregulatory functions than towards growth (Fiance, 1978). Growth rates of nymphs collected from the hard and soft water sites between July, 1990 and January, 1991 were similar at each site for comparable age classes and sexes. Laboratory growth rates of A. lycorias nymphs reared at high and low water hardnesses with unlimited space and food were also not significantly different. While these results reflected the annual P/B ratios calculated from production estimates, they were not predicted by the osmoregulation hypothesis. When laboratory growth rates of second-year nymphs were compared to field growth rate data for the same age class, a slight difference in rates was observed. Mean stream growth rates for the June to October period of 1990 were calculated by averaging available monthly growth rates data collected 104 frcnn July, 1990 to October, 1990 (Table 18). Mean laboratory growth rates for female and male nymphs removed from the Ford River and reared in hard water laboratory streams were lower than those caculated from field data; 0.0061 day’1 in the laboratory, compared to 0.0070 day'1 in the field. Peshekee River organisms grew slightly better in the laboratory stream (0.0062 day'l) than in the field (0.0050 day'l). Since the laboratory stream water temperatures were maintained at a constant temperature unlike that in the field, it is not possible to determine whether differential intraspecific or interspecific competition for food or space exists for second year nymphs in each stream. A method for measuring growth rates for individual nymphs living in the streams would have to be developed before any conclusions regarding competition could be made with certainty. Other growth rate data for Acroneuria species in the literature are limited. Other published studies dealing with Acroneuria growth rates used methods that were not comparable to those used in this study (Heiman and Knight, 1975; Siegfried and Knight, 1978; Schmidt and Tarter, 1985). In a growth study of a pleurocerid snail conducted in six Alabama streams of different alkalinities, Huryn (1991) found that natural stream growth rates were not correlated with alkalinity. Within the context of this study’s hypotheses and results, possible factors regulating secondary production at the F81 and PS1 sites can be examined (Figure 26). The first $2.2m? .2... .29... tom 0.... o.o: E «5.8.... moron». .4 .o 5.8.69... .355 3.2.3.2.. 2202 Ho Egon... 26.". .8 2:9“. e ooou. mo“. _ 20:55:00 . 6 e mmozmcmuua 32355... oz e muozummta — 8.. _ «taxman... _ .EozooE _ _ $5.85 _ 800.5 025285 — o mmozmmmu—u—E . - 9 202.435: 105 2 e 8055...... - - «2.... 55$. 8.. «Summon... 9 2053005. h >Ozu_OEn—m ZOFSDGNEOEmO oz ”mks..— ¢m>Oz¢=h 20:52.8 _ £5.30. h mmozmmmmma mcahémafim... _ e ooou. co“. 8.. _ e Summit... (maestion, asking whether production was really different between the two sites, was clearly answered. Production at FSl was greater than that at P81. By separating the production estimates into the components of standing stock biomass and turnover ratios, it was evident that differences in standing stock biomass between sites were greater than the differences in turnover ratios. This lack of inter-site difference in turnover ratios was substantiated by growth rate data collected in the field and in the laboratory. Therefore, factors such as stream water temperature differences, competition differences and osmoregulatory efficencies are not strongly affecting growth rates. The next logical step would be to determine what factors are influencing the standing stock biomass at each site (Figure 26). Several of these factors were given a cursory examination in the present study. The ratios of effective habitat area to bottom area were determined to be similar at each site. This determination was made for the riffle habitat at each site and may not be extended to the entire stream continuum. A greater predation risk for A. lycorias by other invertebrates and fish at the PSI site is an alternate explanation. Fish predation was found to significantly reduce Paragnetina densities (Feltmate and Williams, 1991). An electofishing survey conducted at each site in August, 1990 indicated that on the sampling date, fish predation would likely have a greater impact on A. 107 lazzggigg standing stocks at FSl rather than PSl (Table 23). This conclusion, based on fish density data collected on one sampling date is weak, but consistent with personal observations made over the entire study period. Fecundity of third-year nymphs in each stream, as discussed earlier, is a trade—off between nymphal size and total number of reproducing nymphs. Before this factor can be eliminated, fecundity data will have to be collected. Differences between sites concerning disturbance and competition for food were not determined in this study. However, these two factors represent the most likely route towards answering the question of why the stream productivity/water hardness correlation exists. Seasonal disturbances will reduce abundances of Agrogeuria species (Siegfried and Knight, 1977) and determine the distribution of stream invertebrates (Stout, 1981; Peckarsky, 1983; Reice, 1985; Statzner and Higler, 1986; Marmonier and Creuze’ des Chatelliers, 1991). The quantity and quality of food has been proposed as the "single most important factor limiting animal abundance" (White, 1978). Algal standing crops and production have been shown to limit secondary production (Benke and Wallace, 1980; Lamberti and Resh, 1983; Huryn and Wallace, 1985). Densities of filter feeding invertebrates have been correlated with fine organic particulate matter (Wallace and Merritt, 1980; Wotton, 1987). Shredder populations were shown to be food limited (Richardson, 1991), 108 Table 23. Results of riffle and pool fish survey of F51 and P31 conducted during August 1990. qualitatively only. Pool habitat sampled Density Density FSl (no./m2) PSl (no./m2) Rim: Bifilfi Rhinichthys cataractae 0.66 Rhinichthys atratulus 0.06 (Longnose dace) (Blacknose dace) Cottus bairdi 0.18 Cottus bairdi 0.02 (Mottled sculpin) (Mottled sculpin) Rhinichthys atratulus 0.12 Phoxinus neogaeus 0.01 (Blacknose dace) (Finescale dace) Etheostoma flabellare 0.07 Micropterus dolomieui 0.004 (Fantail darter) Percina maculata 0.04 (Blackside darter) Salvelinus fontinalis 0.01 (Brook trout) Etheostoma nigrum 0.003 (Johnny darter) Lota lota 0.003 (Burbot) Ecol Catostomus catostomus (White sucker) Rhinichthys atratulus (Blacknose dace) Rhinichthys cataractae (Longnose dace) Semotilus atromaculatus (Creek chub) Lota lota (Burbot) Etheostoma nigrum (Johnny darter) Etheostoma flabellare (Fantail darter) (Smallmouth bass) Emil Semotilus atromaculatus (Creek chub) Cottus bairdi (Mottled sculpin) Micropterus salmoides (Largemouth bass) 109 and fish.production has been limited by food resources (Cada et. al., 1987). Disturbance and competition may also act together to limit production in streams. Peckarsky (1983) proposed the harsh-benign model to explain the role of biotic and abiotic factors in stream community structure. The model predicts the relative importance of abiotic factors, competition and predation on community structure over a gradient of environmental conditions ranging from harsh to benign. Initial research has shown that the model is a good predictor of predator impact on prey species (Peckarsky et. al., 1990). Recently, Hemphill (1991) demonstrated experimentally that seasonal disturbances, along with competition, played roles in regulating flydropsyche and simulium abundances in a California stream. Collier and Winterbourn (1990) reported lower production of Qeleatigm in acid streams compared to alkaline streams, and concluded that lower quality epilithic food in the acid stream was responsible for the lower production values. However, evidence presented in their paper of differential flow regimes and stream channel stability were not factored into their conclusions. The final objective of this study was to narrow the scope of the problem for future research regarding the stream productivity/water hardness correlation. From data presented in this study, it is clear that the lower production estimates of A. lycgrias at the soft water site are a result 110 0f physical, biological or habitat constraints on standing crop biomass, rather than slower growth rates due to cation concentrations. These constraints, particularly disturbance and competition for food and habitat, will form the basis of future hypotheses developed to determine specific factors regulating secondary production in a hard and soft water stream. SUMMARY The life history, density, standing crop biomass, production and growth of a stonefly, Acroneuria lycorias were compared between fourth-order hard and soft water streams in Michigan’s upper pennisula from 1988 to 1990. Conductivity, pH, total alkalinity and total hardness, and Ca2+ MgZ+, Na+ concentrations varied significantly between the hard water Ford River (~ 133 mg CaCO3/L) and the soft water Peshekee River (~ 14 mg CaCO3/L). Water temperature, dissolved oxygen, soluble reactive phosphorus and nitrate concentrations were similar at sites in each stream. Discharge was found to fluctuate more during spring and fall seasons in the soft water stream than in the hard water stream. A. lycorias nymphs exhibited a three-year life cycle in each stream. Mean weights of female nymphs of second and third year cohorts were greater than male nymphs of the same age. Nymphs of all size classes at the soft water site were slightly larger than those at the hardwater site. Foregut contents of nymphs from both streams indicated that A. lycorias was a predator, and an opportunist type feeder. 111 112 Mean densities of nymphs were higher (100 ind./m2) at the hard water site than at the soft water site (40 ind./m2). Mean standing crop biomass for organisms at the hard water site over the two year period was 1.52 g dry weight 111‘2 compared to 0.31 g dry weight m'2 for nymphs at the soft water site. Mean annual production of A. lycorias was 5.0 times greater at the hard water site (2.18 g dry weight m‘Z) between 1988 and 1990 than that at the soft water site (0.43 g dry weight m'Z). Growth rates of A. lycorias nymphs collected from the hard and soft water sites between July 1990 and January 1991 were similar at each site for comparable age classes and sexes. Laboratory growth rates of A. lycorias nymphs reared at high and low water hardnesses with unlimited space and food were not significantly different. Low A. lygorias production estimates at the soft water site were a result of physical, biological or habitat constraints on standing crop biomass, rather than slower growth rates due to low water hardness. APPENDIX A PHYSICAL AND CHEMICAL WATER DATA TABLES w.v o.o mm. FMH ~.m om o.oH o.H pmm m.HH o.HN >~\m m.m m.m omH no. m.m moa H.0H o.H mmw o.mH m.- mm\m o.v H.> msfl mmH v.m «m m.m H.H wmm o.mH o.om a~\> m.m h.w mva vNH m.m «OH h.m o.o mnm o.n~ o.>n owxw v.m o.m OMH wOH ~.m mm m.HH 5.0 now o.m o.m~ Hm\v m.v >.w wwH mwa o.o mm o.mH o.~ How m.o o.o: n\m m.v n.0H mma wnH m.> hm >.~H F.H Haw m.o H.o: waa add m.v In hmH mmH w.> FF ~.HH a.H New m.o n.01 oa\~H m.~H o.m mwa Hva v.o ma o.oa ~.H wmm o.HH n.mH o~\oa H.a v.m mm. mva v.m hm m.m v.H mam o.wH m.- «\m m.« m.> omH nod n.w MOH 0.0H v.H mmw m.wH o.Hn maxo m.« w.. aha me m.m Hoa o.o m.H oww m.v~ o.on mxo o.m v.w mp. owe «.m HOH H.m ~.H omw m.o~ m.w~ n~\> o.m o.o NwH mvH m.m om m.> H.H omm o.m~ m.mH w\> o.m m.m mNH woa w.» an v.o m.H mwa o.oa m.n~ -\w m.m o.v ONH mu ~.o mm w.~H >.o ONH m.n m.H w\m ¢.v H.m aha mma o.> am ~.nH o.o mma n.o m.Hu owxn 1. m.v >.m med wvH h.h om m.HH o.H now o.H o.n| aflxw 1 «a 1 H.v m.m omH «ma w.> mm m.NH o.o vaw o.H o.m| mwxwa o.v o.o moH mp m.n Na o.nH w.H ow. m.H o.~ awxofl m.m m.m ova NNH m.w woe H.0H o.H oo~ m.mH m.>~ hxm ~.o ~.m wwH hma v.m Hm a.m m.H oaw m.wfl o.wa on\m o.v v.a me NmH v.a mm v.w m.H cow o.- o.m~ ma\m II In va «Ha ~.m mm H.m H.~ omw n.a~ o.mn wxm w.m m.> «ma onH m.o NOH >.m o.H new o.m~ m.mn mw\> ad 33.... 33.... 33.... 33.... 3. 33.... 233...... 6.. 8.. tau Noam mun: >uacax mm .uuaumm =om>xo aua >ua>au .QEOH .mea span Icnmm .H umxa¢ .9 ucouumm .mman updnusa nospcou “was: uam .oamalmmma .cmoasoaz .Amuwm Hmm. u0>am puom onu uo huaamsu noun: HMUHEwco pan Huoanazm .HI< wanna 0.0 m.v «m HH >.w 00 «.0 0.0 «m 0.MH 0.m~ wm\m m.0 0.0 mm vw 0.0 Nm «.0 m.H me 0.a~ 0.>~ v~\0 v.0 v.0 0m 0H 0.p Hm H.0 0.H mm 0.H~ 0.0m H~\> 0.0 p.~ mm ma ~.> we m.> 0.0 an 0.- 0.mm mwxw «.0 I: 0H m 0.0 00 o.aH >.0 Hm 0.n m.w~ waq ~.0 5.0 pm 0H 0.0 u: I: 0.0 Mg m.0 n.0n v\m ~.0 m.> mm ma F.w v0 m.~a 0.0 pm m.0 m.0: H~\H ddfld 0.0 0.0 FN NH p.w he ~.HH 0.0 mm m.0 n.0u oaxwa w.o ~.N mm N... 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Calculation of production of A. lxcorias at the Ford (831 site) River, 1988—1989. Length N W B Wt at loss Wt loss X 25 (mm) (no./m2) (g) (g/m2) No. loss/m2 Ave W Ave WAN (g/mZ/yr) 0 - 1 0.27 0.0000 0.0000 1 - 2 0.54 0.0001 0.0001 -0.2714 0.0000 0.0000 -0.0003 2 - 3 5.67 0.0002 0.0014 -5.1286 0.0001 —0.0008 -0.0189 3 — 4 17.58 0.0006 0.0099 -11.9086 0.0004 -0.0047 -O.1169 4 - 5 9.21 0.0011 0.0096 8.3658 0.0008 0.0068 0.1710 5 - 6 3.26 0.0019 0.0058 5.9571 0.0015 0.0087 0.2186 6 - 7 4.06 0.0029 0.0124 ~O.8000 0.0024 —0.0019 —0.0478 7 - 8 2.99 0.0043 0.0130 1.0714 0.0036 0.0039 0.0971 8 - 9 2.71 0.0061 0.0165 0.2715 0.0052 0.0014 0.0354 9 - 10 0.54 0.0083 0.0045 2.1714 0.0072 0.0156 0.3902 10 - 11 1.63 0.0109 0.0181 -1.0857 0.0096 —0.0104 -0.2606 11 — 12 2.17 0.0141 0.0304 -0.5429 0.0125 -0.0068 -O.1695 12 — 13 1.89 0.0177 0.0348 0.2857 0.0159 0.0045 0.1134 13 - 14 1.90 0.0219 0.0437 —0.0143 0.0198 -0.0003 -0.0071 14 — 15 3.53 0.0268 0.0972 -1.6285 0.0244 -0.0397 —0.9917 15 - 16 0.81 0.0323 0.0265 2.7143 0.0295 0.0801 2.0026 16 - 17 2.44 0.0384 0.0938 —1.6286 0.0353 -0.0575 -1.4384 17 - 18 2.71 0.0453 0.1223 -0.2714 0.0418 -0.0114 -O.2839 18 - 19 2.99 0.0529 0.1588 -0.2715 0.0491 -0.0133 -O.3331 l9 - 20 1.90 0.0613 0.1153 1.0857 0.0571 0.0620 1.5493 20 - 21 1.36 0.0705 0.0959 0.5429 0.0659 0.0358 0.8942 21 - 22 1.63 0.0806 0.1349 -0.2715 0.0755 -0.0205 -0.5126 22 - 23 1.09 0.0915 0.1144 0.5429 0.0860 0.0467 1.1677 23 - 24 0.27 0.1034 0.0288 0.8143 0.0975 0.0794 1.9839 24 - 25 0.00 0.1162 0.0000 0.2714 0.1098 0.0298 0.7451 1.1880 5.1880 Total Production - 5.1880 x 0.333 (CPI correction) - 1.728 g/m2/yr 119 Table B-2. Calculation of production of _A_. lxcorias at athe Ford (F81 site) River, 1989-1990. Length N W B Wt at loss Wt loss X 25 (mm) (no./m2) (g) (g/m2) No. loss / m2 Ave W Ave WAN (g/mZ/yr) 0 - 1 0.00 0.0000 0.0000 1 — 2 1.42 0.0001 0.0001 -1.4188 0.0000 -0.0001 -0.0013 2 - 3 14.30 0.0002 0.0036 -12.8812 0.0001 —0.0019 -0.0475 3 - 4 . 12.65 0.0006 0.0075 1.6500 0.0004 0.0006 0.0162 4 - 5 25.41 0.0011 0.0291 -12.7563 0.0008 ~0.0104 -0.2607 5 - 6 10.19 0.0019 0.0183 15.2188 0.0015 0.0223 0.5583 6 - 7 3.21 0.0029 0.0096 6.9812 0.0024 0.0167 0.4171 7 — 8 2.61 0.0043 0.0113 0.5938 0.0036 0.0022 0.0538 8 - 9 1.31 0.0061 0.0081 1.3062 0.0052 0.0068 0.1701 9 - 10 1.78 0.0083 0.0155 -0.4750 0.0072 -0.0034 -0.0854 10 - 11 2.73 0.0109 0.0305 -0.9438 0.0096 -0.0091 -0.2265 11 - 12 3.44 0.0141 0.0489 -0.7187 0.0125 -0.0090 -0.2243 12 - 13 2.14 0.0177 0.0389 1.3063 0.0159 0.0207 0.5187 13 - 14 3.56 0.0219 0.0792 -1.4250 0.0198 -0.0283 -0.7064 14 - 15 5.11 0.0268 0.1378 -1.5438 0.0244 -0.0376 -0.9401 15 - 16 6.06 0.0323 0.1988 -0.9500 0.0295 -0.0280 -0.7009 16 - 17 4.63 0.0384 0.1796 1.4250 0.0353 0.0503 1.2585 17 - 18 5.69 0.0453 0.2560 -1.0625 0.0418 -0.0444 -1.1112 18 - 19 3.92 0.0529 0.2075 1.7750 0.0491 0.0871 2.1776 19 - 20 1.54 0.0613 0.0960 2.3750 0.0571 0.1356 3.3891 20 - 21 1.66 0.0705 0.1184 -0.1187 0.0659 -0.0078 -0.1955 21 - 22 2.49 0.0806 0.1972 -0.8313 0.0755 -0.0628 -1.5696 22 - 23 1.78 .09151.5 0.1766 0.7125 0.0806 0.0574 1.4350 23 - 24 0.00 0.1034 0.0000 1.7813 0.1034 0.1842 4.6044 24 - 25 0.24 0.1162 0.0316 -0.2375 0.1098 -0.0261 -0.6520 1.9000 7.8775 Total Production - 7.8775 x 0.333 (CPI correction) = 2.623 g/m2/yr 120 Table B-3. Calculation of production of £9 lvcorias at the Peshekee (P51 site) River, 1988-1989. Length N W B Wt at loss Wt loss X 25 (mm) (no./m2) (g) (g/mZ) No. loss/m2 Ave W Ave W‘N (g/mZ/yr) 0 - l 0.00 0.0000 0.0000 1 - 2 1.63 0.0001 0.0001 -1.6285 0.0000 -0.0001 -0.0013 2 — 3 4.33 0.0002 0.0010 -2.7001 0.0001 -0.0003 -0.0083 3 - 4 8.91 0.0005 0.0041 -4.5857 0.0003 -0.0015 -0.0375 4 - 5 4.61 0.0009 0.0042 4.3001 0.0007 0.0030 0.0742 5 - 6 1.09 0.0016 0.0017 3.5286 0.0012 0.0044 0.1100 6 — 7 1.09 0.0025 0.0029 -0.0001 0.0020 0.0000 0.0000 7 - 8 1.09 0.0037 0.0038 0.0000 0.0031 0.0000 0.0000 8 - 9 1.36 0.0053 0.0070 -0.2714 0.0045 -0.0012 -0.0306 9 — 10 1.09 0.0072 0.0078 0.2715 0.0063 0.0017 0.0424 10 — 11 1.63 0.0096 0.0162 -0.5429 0.0084 -0.0046 -0.1138 11 - 12 0.27 0.0123 0.0031 1.3571 0.0110 0.0149 0.3716 12 - 13 1.36 0.0156 0.0209 -1.0857 0.0140 -0.0152 -0.3795 13 — 14 0.27 0.0194 0.0050 1.0857 0.0175 0.0190 0.4755 14 - 15 0.27 0.0238 0.0067 0.0000 0.0216 0.0000 0.0000 15 - 16 0.54 0.0287 0.0155 -0.2714 0.0262 -0.0071 -0.1780 16 - 17 1.09 0.0343 0.0386 -0.5429 0.0315 —0.0171 -0.4274 17 - 18 0.27 0.0405 0.0105 0.8143 0.0374 0.0304 0.7612 18 - 19 0.54 0.0474 0.0256 —0.2714 0.0440 -0.0119 -0.2983 19 - 20 0.54 0.0551 0.0298 0.0000 0.0513 0.0000 0.0000 20 - 21 0.00 0.0635 0.0000 0.5428 0.0593 0.0322 0.8047 21 - 22 0.27 0.0727 0.0203 -0.2714 0.0681 —0.0185 —0.4622 22 - 23 0.00 0.0828 0.0000 0.2714 0.0778 0.0211 0.5276 23 — 24 0.00 0.0937 0.0000 0.0000 0.0883 0.0000 0.0000 24 - 25 0.00 0.1055 0.0000 0.0000 0.0996 0.0000 0.0000 0.2249 1.2302 Total Production - 1.2302 x 0.333 (CPI correction) = 0.410 g/m2/yr 121 Table B-4. Calculation of production of A. lxcorias at athe Peshekee (P51 site) River, 1989-1990. Length N W Wt at less Wt loss X 25 (mm) (no./m2) (g) (g/m2) No. loss/m2 Ave W Ave WAN (g/mZ/yr) 0 - 1 0.54 0.0000 0.0000 1 - 2 2.57 0.0001 0.0002 -2.0286 0.0000 -0.0001 -0.0016 2 - 3 3.12 0.0002 0.0007 -0.5499 0.0001 -0.0001 —0.0017 3 - 4 8.51 0.0005 0.0041 -5.3929 0.0003 -0.0018 -0.0442 4 - 5 7.98 0.0009 0.0070 0.5357 0.0007 0.0004 0.0092 5 - 6 7.31 0.0016 0.0118 0.6648 0.0012 0.0008 0.0207 6 - 7 0.81 0.0025 0.0020 6.4995 0.0020 0.0133 0.3319 7 - 8 1.90 0.0037 0.0073 -1.0857 0.0031 —0.0034 -0.0845 8 - 9 1.22 0.0053 0.0063 0.6785 0.0045 0.0031 0.0764 9 - 10 0.54 0.0072 0.0040 0.6786 0.0063 0.0042 0.1060 10 — 11 1.09 0.0096 0.0103 -0.5428 0.0084 -0.0046 -0.1138 11 - 12 0.95 0.0123 0.0118 0.1357 0.0110 0.0015 0.0372 12 — 13 0.95 0.0156 0.0149 0.0000 0.0140 0.0000 0.0000 13 - 14 1.22 0.0194 0.0246 -0.2715 0.0175 -0.0048 -0.1189 14 - 15 0.81 0.0238 0.0190 0.4072 0.0216 0.0088 0.2198 15 - 16 0.41 0.0287 0.0118 0.4071 0.0262 0.0107 0.2670 16 - 17 0.27 0.0343 0.0093 0.1357 0.0315 0.0043 0.1068 17 - 18 1.09 0.0405 0.0451 -0.8143 0.0374 -0.0304 -0.7612 18 - 19 0.81 0.0474 0.0399 0.2714 0.0440 0.0119 0.2983 19 — 20 0.68 0.0551 0.0364 0.1358 0.0513 0.0070 0.1740 20 - 21 0.00 0.0635 0.0000 0.6785 0.0593 0.0402 1.0059 21 - 22 0.41 0.0727 0.0292 —0.4071 0.0681 -0.0277 -0.6933 22 - 23 0.27 0.0828 0.0294 0.1357 0.0778 0.0106 0.2638 23 - 24 0.00 0.0937 0.0000 0.2714 0.0883 0.0240 0.5988 24 - 25 0.14 0.1055 0.0147 -0.1357 0.0996 -0.0135 -0.3380 0.3396 1.3587 Total Production 1.3587 x 0.333 (CPI correction) = 0.452 g/mZ/yr LITERATURE CITED Allen, K. 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