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ECOLOGICAL FACTORS INFLUENCING
MACROINVERTEBRATES IN THE PINE RIVER

Thesis for the Degree of Ph. D.
MICHIGAN STATE UNIVERSITY
WILIARD E. BARBER
197D

 

 

 

     
     

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University

This is to certify that the

thesis entitled

Ecological Factors Influencing Macroinvertebrates
of the Pine River

presented by

Willard Eugene Barber

has been accepted towards fulfillment
of the requirements for

Ph.D. . Fisheries 8: Wildlife
degree 1n

 

 

 

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Date 111/20/70

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ABSTRACT

ECOLOGICAL FACTORS INFLUENCING MACROINVERTEBRATES
IN THE PINE RIVER

BY

Willard Ea Barber

Influences of substrate, macrophyte growth and detritus
on macroinvertebrate standing crop distribution, numbers
and biomass (ash—free dry weight), as well as seasonal vari—
ations in standing crop were investigated in a marginal
trout stream.

Seasonal maxima and minima in numbers and biomass are
given for ephemeropterans, chironomids, simuliids, other

dipterans, trichopterans, and trichopteran Helicopsyche

 

borealis, coleopterans, water mites and plecopteranso
Percentage pupae and/or average weight/individual are given
for each group and are discussed in relation to pOpulation
changes. Annual production is estimated, 654 g/m2, by
using Waters' constant turnover ratio 5050

Ephemeropterans show no consistent relationship to large
or small substrates, either numbers or biomass. Numbers of
dipteran larvae do not show a definite relationship to sub-
strate size, reflecting the relationship of chironomids and

simuliids, but a larger biomass is associated with larger

Willard E. Barber

substrates, reflecting the association of larger dipterans.
Higher numbers and biomass of trichopterans are associated
with larger substrates. The trichopteran Helicopsyche
borealis also shows the preceding relationship. Numbers of
coleopteran larvae show no relation to substrate size, but
biomass is greater in large size substrates. Biomass and
numbers of water mites are generally associated with larger
substrates, whereas there is no relationship in plecopterans.

Larger numbers and biomass of ephemeropterans, dipterans
(chironomids and simuliids but no others) and trichopterans
are associated with macrophyte beds; this is attributed to
drifting species and those that have summer generations.
macrophyte growth seems to reduce numbers and biomass of
‘E. borealis, but no differences are observed in coleopterans
or plecopterans.

In a substrate substitution study, ephemeropterans,
chironomids, coleopterans and oligochaetes are significantly
related to smaller substrates, whereas dipterans (less chirono-
mids) and trichopterans are not significantly related to
substrate type. _Significantly higher numbers are related to low
and medium foodlevels rather than high. The relationship to
smaller substrates may be related to a reduction in inter-
stitial Space (as compared to the large substrates) and the
lack of Special heterogeneity in large substrates. Higher

numbers related to low and medium food levels is suggested

Willard E. Barber

due to low oxygen levels below the substrate's surface in
the high food levels or due to detritus being in large
packets with a great deal unavailable to invertebrates.

For the clam Sphaerium striatinum, highest numbers

(1005/m2) and biomass (3.54 g/mg) occur during summer and
Higher

fall, whereas lowest are observed in late winter.
numbers and biomass are generally associated‘with smaller
substrates with no differences between macrophyte and riffle

habitats. The majority of the young are extruded when they

are 3.6 to 5.8 mm in length.
but growth could not be interpreted from length frequency

Maximum size reached is 15.5

nun,
Adults contain as high as four young, but the

histograms .

ma j ority contain two .

ECOLOGICAL FACTORS INFLUENCING MACROINVERTEBRATES

IN THE PINE RIVER

BY :9 .9
. ")3
Willard E3”Barber

A THESIS

Submitted to
Michigan State University
in partial fulfillment of the requirements
for the degree of

DOCTOR OF PHILOSOPHY

Department of Fisheries and Wildlife

1970

isli

(:v‘

ACKNOWLEDGEMENTS

Special thanks are extended to my major professor,

for his support throughout my tenure

Dr. Niles R. Kevern,
I also

as a graduate student at Michigan State University.
wish to thank Drs. William E. Cooper, Eugene W. Roelofs and
Gordon E. Guyer for reading and criticising the manuscript.
Rev. H. B. Herrington identified Sphaerium striatinum and

Drs. John L. Gill and William E. C00per gave advice liberally

concerning statistical analysis. Fellow graduate students

deserve thanks, particularly Frank J. Tesar, who gave

assistance readily and made the field trips interesting.
Without the financial assistance of a grant from the

Dow Chemical Company and funds from the Agricultural Experi—

ment Station, Michigan State University, this study would not

haVe been possible.
Last, but not least, I am particularly grateful to my

wi fe Bonnie for her understanding and help during my graduate

st7-l:l<iies and to Catey for relaxing moments when they were

needed.

ii

TABLE OF CONTENTS

 

Page

INTRODUCTION.................... 1
STUDY AREA, METHODS AND MATERIALS. . . . . . . . . . 4
RESULTS AND DISCUSSION . . . . . . . . . . . . . . . 8
Factors Influencing Standing Crop Distribution. 8

Field Observations . . . . . . . . . . . . 8

Substrate and Food Manipulation. . . . . . 26

Seasonal Variations in Standing Crop. . . . . . 55
Annual.Production Estimate. . . . . . . . . . . 54
Observations of Sphaerium striatinum. . . . . . 55
Standing CrOp and Habitat. . . . . . . . . 56

Growth and Reproduction. . . . . . . . . . 65

GENERAL CONCLUSIONS. . . . . . . . . . . . . . . . . 71
LITERATURE CITED 0 O O O O O O O O O O O O O O O O O 75

iii

LIST OF TABLES

TABLE

1.

Average estimate of individuals/m2 at each time
period (TP) associated with small and large

substrates from a riffle area of the Pine River
(n=number of samples). . . . . . . . . . . . . .

Average estimate of biomass (g/m?) at each time
period (TP) associated with small and large sub-
strates from a riffle area of the Pine River
(n=number of samples). . . . . . . . . . . . . .

Average estimate of numbers/m? and biomass
(g/ma) (in parentheses) in macrophyte beds
(present) and in riffles (absent) during summer
and fall 1968 (n=number of samples). . . . . . .

Particle size distribution by weight of four

samples, two from each size category, from sub-
strates substituted in a riffle area of the Pine
River. . . . . . . . . . . . . . . . . . . . . .

Analysis of variance and orthoganal contrasts on
numbers of organisms in six groups with food
level and substrate manipulations in a riffle
area of the Pine River. Data for Chironomidae
were transformed to common logarithms. In con-
trasts L=large and S=small substrates, 1, m, and
h indicate' low, medium, and high food levels,
respectively . . . . . . . . . . . . . . . . . .

Ninety-five percent confidence intervals on
number/ml of sample of six groups associated
with different treatment combinations placed in
a riffle area of the Pine River. L=large and
S=small substrates, 1, m, and h are low, medium
and high food levels, respectively . . . . . . .

Average estimate of individuals/m? in a riffle

area of the Pine River on each collection date.
Ranges are in parentheses. . . . . . . . . . . .

iv

Page

10

11

15

27

29

50

56

IJST OF TABLES-~continued

TABLE

8.

1CL

11..

.123.

1125.

Average estimate of biomass (g/ma) in a riffle
area of the Pine River on each collection date.
Ranges are in parentheses. . . . . . . . . . . .

Average numbers/m? and grams/m2 of Sphaerium

striatinum on each sampling date. Two standard

deviations in parentheses. . . . . . . . . . . .

Relationship between average numbers/m2 and bio-
mass in grams/m2 of Sphaerium striatinum and sub-
strate type with time. Two standard deviations
in parentheses; none is given when only one
sample is present. . . . . . . . . . . . . . . .

Average numbers/m2 and biomass in grams/m2 of
Sphaerium striatinum associated with habitat
type. Two standard deviations in parentheses.
Only one sample obtained from macrophyte bed on
each date. . . . . . . . . . . . . . . . . . . .

.Relationship between size and frequency of

number of young contained in brood pouches of
adult Sphaerium striatinum . . . . . . . . . . .

Percentage of Sphaerium striatinum population
over 7.4 mm in length containing young by collec-
tion date. 0 C O O O O O O O O O O O O O O :‘ O O

Page

58

59

61

62

68

69

LIST OF FIGURES

FIGURE Page

1. Seasonal changes in 2average estimate of stand—
ing crop, numbers/m2 and biomass (g/m2 ), of
various groups from a riffle area of the Pine
River. . . . . . . . . . . . . . . . . . . . . . 55

2. Seasonal changes in average estimate of stand-
ing crop, numbers/m? and biomass (g/m?), of
various groups from a riffle area of the Pine
River. . . . . . . . . . . . . . . . . . . . . . 46

3. Seasonal changes in average estimate of total
standing crop, numbers/m2 and biomass (g/m2 ),
from a riffle area of the Pine River . . . . . . 58

4. Seasonal changes in standing crop of _phaerium
striatinum, numbers/m2 and biomass (g/mz), in a
riffle area of the Pine River. . . . . . . . . . 58

 

ES. Length frequency distributions for collections
of Sphaerium striatinum, by date, from the Pine
River 0 O O O O O C I O O O O O O O O O O O O O O 67

vi

INTRODUCTION

There has been increasing interest in stream ecology
in recent years, not only because of problems in pollution
but also in an attempt to increase knowledge concerning the
tiynamics of stream ecosystems to better understand natural
idufluences and to predict consequences of human activities.
Ax: understanding of the dynamics of the benthic fauna, in

relation to physical and biological aspects of the stream,

is a prerequisite to this knowledge.
There have been numerous studies on benthic faunas, but

many study a few specific Species, lack information concern-
ing relationships to the biological or physical components

0f the stream or are so broad in scope as to give a general
overview of ecological relationships. Percival and Whitehead

(1929), Jonasson (1948), Minckley (1965), Cummins (1964a,b),
Cummins and Lauff (1969), Egglishaw (1969), Mackay and Kalff
(1989) have demonstrated influences of substrate and macro-
phEf‘tes on the distribution of standing crop of benthic fauna.
Nelson and Scott (1962), Egglishaw (1964), Minshall (G. W.,
153637), Mackay and Kalff (1969) have demonstrated that detritus

13 also an important factor in distribution and support of

Standing crops. There have also been a number of studies on

seasonal changes of standing crops of benthic organisms in

streams (Hynes, 1961: Minckley, 1965; Egglishaw and Mackay,

1969: and others). But the majority of these studies have

dealt with numbers, ignoring or giving little reference to

biomass, and with numerical estimates being based only on

insects caught in large meshed screens, ignoring young indi-

viduals that may make up 50% or more of the total fauna
hionasson, 1955: Macan, 1958; Maitland, 1966).
This paper is concerned with the influence of substrate,

food (detritus) and macrophytic growth on macroinvertebrate

standing crop distribution. Food manipulations under field

conditions have demonstrated the existence of food limitation
in a number of populations (Eisenberg, 1970); therefore, an
experiment was conducted in the stream to determine the effect
of a food (detritus in the present case) and substrate sub-
Stitution on distribution of numbers to strengthen field data

and determine quantitatively the effects and interaction of

the two factors. This studyis concerned also with seasonal

variations in standing crOp, numerical and biomass, with
e1""iDl'Iasis on estimating the total population of those organ—

isms studied. From this data an attempt is made at estimat-

lng annual production.
These previous objectives evolved from a concern about

the multiple use of rivers for hydroelectric installations,

flood control, and recreation that has become extensive in

the United States, and because there is a need for documen—
tation of biological and physical conditions before a stream
is altered by a dam. Therefore, this work is part of a
series of ecological studies on the Pine River which will
provide information that will lead to a better understanding
of the ecological effects of such alteration of stream

ecosystems.

STUDY AREA, METHODS AND MATERIALS

The study was conducted from June 1968 to October 1969

in the Pine River, Montcalm County, Michigan. The stream

above the study area drains about 259 km2 (100 milea) of

which approximately 70% is agricultural, the rest aspen-oak

hardwoods. The stream is alkaline, averaging about 200 ppm

CaCOa, with summer daytime temperatures ranging from 17-25 C.

It has a gradient of 0.95 m/km (5 ft/mile) . Discharge ranged

from 0.96 ma/sec (54 CFS) to 1.59 ma/Sec (45 CFS) in the

summer but was somewhat larger during Spring runoff.
The sampling site was a riffle area 200 m in length with

an average width of 10 m, downstream from the Tamarack Road

crossing (edge of Secs. 8-17, T-12N, R-5W). Six samples,

selected randomly from a random numbers table, were taken
With a Petersen dredge having an area of 651 cm2 at biweekly

intervals throughout the Spring, summer and fall months.

During the winter months samples were taken only twice, in

late November and early March. Although six samples were

taken on each date, all were not used.
The samples were placed in buckets with 10% formalin

added and taken to the laboratory. Excess liquid was poured

through No. 50 and No. 60 mesh (0.5 mm and 0.246 mm mesh

openings, respectively) Tyler sieves placed in sequence.

The invertebrates were removed by the sugar flotation tech-

nique (Anderson, 1959) . The remaining material was placed in

a white enamel pan and examined for remaining invertebrates.

The material in each sieve was placed in separate jars and

75% ethyl alcohol added. It often was necessary to deal with

only part of a sample because of large amounts of detritus

which floated on the sugar solution; therefore, two or three

subsamples were taken from each (number of ml subsampled

varied depending on the total amount of the sample), picked

under a dissecting microscope, enumerated, and the total

number estimated in each by simple proportion and averaged to

give a mean estimate in the sample. These estimates were

added to give an estimate of the total number of invertebrates
in the sample and expressed as the number/m2 or biomass/m2.
Ash-free dry weights were determined by placing the sub-
samples in small planchets and drying at 105 C for 48 hours.
The subsamples were then placed in a dessicator and allowed

to cool to roomtemperature, weighed to the nearest 0.01 mg,

then ashed at 600 C for one hour, again allowed to cool to

r00m temperature in a dessicator, and reweighed. Errors

introduced by inorganic gut contents are avoided by this

teChnique (Scott and Nelson, 1962) .

In order to determine the various substrate particle
SiZes present, samples of the stream bottom were taken im-

mediately adjacent to the area sampled for invertebrates.

The sampler, a cylinder 8.5 cm in diameter, was pushed into

the substrate to a depth of approximately 7.5 cm. The upper

end was enclosed to prevent the loss of silt and clay. Once

the sampler was in place in the substrate, a thin metal plate

was forced under the end, the sample removed and placed in

a container. In the laboratory, substrate samples were ana-

lyzed for particle size distribution by a combination of two

methods: the settling velocity method for silt and clay, and

dry sieve analysis for the substrate materials 1.16 mm and

greater (Cummins, 1962).
For the settling velocity method, each sample was agi-

tated vigorously after water was added. The resulting silt

and clay suspension was decanted. This process was repeated

three to six times depending on the amount of silt and clay.

The suspension was then placed in gallon glass jars, allowing

the: silt component to settle. The water, still containing the

Clary'suspension, was siphoned through a Foerst centrifuge.

At 'this time the precipitated clay and silt were placed in

Separate porcelain dishes. The remainder, consisting of

coarse substrate, silt and clay fractions were oven dried at

105 c,

Dry sieving of each sample involved the use of a me-

Cfllarrical shaker (Ro-Tap) and nine U. 8. Standard Sieves with

the following openings: 16, 8, 4, 2, 1/2, 1/4. 1/6 mm. In

addition, a single square of heavy wire was constructed with

an Opening of 32 mm. The weights of each of these 12 particle

size fractions were determined for each sample to the near-
est 0.01 9. Following Cummins' technique (1962) the sediment

size classes were converted to the phi scale.

RESULTS AND DISCUSSION

Factors Influencing Standing Crop Distribution

Field Observations
Differences in standing crop and faunal relationships

in respect to substrate (see Cummins, 1964b, and Cummins and

Lauff, 1969, for reviews) and aquatic plants (Percival and

Whitehead, 1929; Whitehead, 1955; Frost, 1942; Jonasson,

194:8; Minckley, 1965) have been observed. In this study in

order to investigate substrate size as a factor in macro-
invertebrate standing crop distribution the median phi value

was used to characterize the substrate from which benthos was

taken (Cummins, 1962) . Samples were divided into two cate-
those that were taken from

gor ies according to phi values:

less--termed small, and those

an area in which phi was 2.7 or

from an area of more than 2.7--termed large. Because either

the large or small category lacked samples in many collections,

data were combined from two consecutive dates (except the last

24 June 1969, which had samples in both cate-

cO llection,
Average standing

gories) giving nine time periods (Tpl-TPQ) .
crop was determined when more than one sample was represented.

Prior studies have compared the faunal composition or

numerical standing crops occurring in macrophytes with that of

‘.

‘s

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v‘.

 

other habitats of the stream. In this study macrophytes

(three species of Potamogeton) were growing in portions of

the riffle area in late May, being sparse at first with little

standing crop (biomass). They became dense, with maximum

standing crop in August, and again reached a low standing

crop in October. As plants grew the current decreased in the

lower portions of the water column with a correSponding
deposition of detrital and inorganic materials through the

summer. To investigate this growth of macrophytes on the

distribution of invertebrate standing crops, on the dates
when samples were taken in macrophytes the average standing
crop was determined for those samples taken in riffle areas
and compared with the standing crops obtained from macrophytes.

As indicated in Tables 1 and 2, there seemingly was a
difference in numbers/m2 and biomass/m2 of ephemeropteran

nyrnphs between the two types of substrates, but neither high

biomass nor numbers was consistently related to either sub-

Strate type. At TP; there were, on the average, more indi—

Vi duals and a larger biomass in the smaller substrates, but at

TPe this association was reversed. T133 showed a higher number

of individuals but a lower biomass associated with the smaller

During TP4 both numbers and biomass were associ-

St3r}3$t:rate .
At TP5 there was a high number

ated with smaller substrates.
of nymphs in larger substrates, and, except for TPe which had

only one sample representing the smaller substrates, this was

maintained through TP9. Biomass also showed the same pattern

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12

from TP5, larger in larger substrates except fbr TPe. These
observations are in contrast to the relationship Pennak and
van Gerpen (1947) found, more nymphs in larger substrates.
Macan (1957) observed that more and smaller nymphs were
generally associated with smaller substrates and observed a
migration in some species when they became large and prior
to emergence. Although the relationship between standing
crops and substrate type, in the present study, was not con-
sistent from TP; through TPe, from TP7 through TP9 numbers
and biomass were higher in the larger substrate at a time
when nymphs would be largest. Thus it may be possible that
there is no definite relationship until nymphs are large, at
which time they move to a larger substrate.

A comparison between macrophyte beds and riffles shows
that on 25 June the number of mayfly nymphs/m2 was higher in
macrophytes (Table 3), but there were more occurring in
riffles on 8 July. On 22 July nymphs occurred in both areas
in about equal numbers. Concurrently the biomass/m2 on the
first date was a little greater in macrophytes, but on 8 and
22 July solid substrates contained a larger amount of biomass.
From 2 September until 6 October the numbers of organisms
inhabiting macrophytes were much higher than in solid sub-
strates. Biomass was greater in macrophyte beds on 2 and 16
September but about equal on 6 October. On the last date both
biomass and numbers were about equal in both types of habitat.

Mayflies have previously been observed to inhabit plants.

15

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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14

Whitehead (1955) found that many parts of the stream were
repopulated from moss areas after the recession of winter
floods, and Frost (1942) found extensive utilizations of
mosses throughout the year. Maitland (1966) found many
nymphs in macrophyte beds but not as high numerically as he
found in riffle areas. In the present study there seemed to
be not consistent numerical relationship with either riffle
or macrophyte habitats from 25 June to 22 July; however,
there was a higher average biomass in the riffle habitat
possibly indicating that smaller individuals were utilizing
the macrophytes. From 2 September to 6 October there was a
large difference in standing crop between the two habitats,
numbers and biomass being greater in the plants. By 24 October
numbers and biomass were nearly equal, undoubtedly due to the
fact that prior to this time plants had begun to die off and
break loose from the bottom; thus areas that were inhabited
by extensive growths of macrophytes were becoming more like a
riffle'habitat.

The disparity between large and small substrate in
average numbers/m? of diptera was great in the first three
time periods (Table 1), more dipterans occurring in the
smaller substrates at TP; and TP3 and more in larger substrates
at TPg. From TP4 to TP9 the differences were not great. At
TP4 and TP5 there averaged more larvae in smaller substrates.
There is a relationship between average biomass/m2 and sub—

strate type (Table 2); the first time period biomass was

15

greater in smaller substrates but associated with larger
types at all other time periods.

Relationship between the number of chironomids and sub-
strate type was identical to dipteran larvae taken as a
whole, which one would expect since chironomids were the
dominant member of the group. Biomass did not follow a simi—
lar pattern. More biomass was associated with smaller
substrate type at the first, third and fourth time periods,
but larger substrates contained more biomass at the other
time periods.

Numbers of blackfly larvae did not Show a constant rela-
tionship to substrate type. At TP; there were more associated
with large substrate, but more were associated with small
substrate in time periods 2, 4, and 5. At TP3 there were no
larvae from the small substrate and very few from larger sub-
strate samples. AT TPe there were more associated with large
substrate whereas more were associated with small substrate
at TP7. At TPB and TP9 more larvae were associated with
large substrates.

Larger numbers of other dipteran larvae, excluding
chironomids and blackflies, were generally associated with
large substrate. At TP; more were associated with the small
Substrate, but higher numbers were in larger substrate from
TP2 to TP4. Again at TPS there were more in small substrate.
At TPe, TP7 and TP9 large substrate contained more larvae,

and at TPa there was a small difference between substrate

16

types with small containing a few more. Larger biomass was
associated with large substrate at all time periods except
the first in which the small type contained a higher biomass.

Numerically dipterans did not Show a relationship to
substrate size nor was there any relationship when chironomids,
simuliids or other dipterans were considered separately.
However, biomass of dipteran larvae as a whole did Show a
relationship, with a larger biomass in larger substrates.
Biomass of chironomid and simuliid larvae did not Show a rela-
tion to substrate type whereas the other dipterans did. Other
dipterans consisted mostly of the large, robust larvae; thus
dipterans taken as a whole reflect the association of biomass
of these large individuals to substrate. Denham (1958) con-
trasted sand and gravel, finding more larvae in gravel but
noted those occurring in sand were much smaller. Pennak and
Van Gerpen (1947) found more chironomids in gravel and sand
than in larger types and more simuliids on bedrock than other
areas. However, they found more other types of dipterans
associated with larger substrates. This association of the
larger dipterans with the larger substrates is undoubtedly due
to growths of algae and moss on the rocks, making refuges
among the growth (Whitehead, 1955; Frost, 1942; Minckley,
1965).

Dipteran larvae as a whole utilized macrophytes exten—
sively as a habitat (Table 5) with both biomass and numbers

generally greater in these beds than in riffles; this

17

association was due to the high occurrence of chironomids

and simuliids. Numbers of chironomid larvae were highest in
riffle areas on the first and third dates but higher in
macrophytes on the second date. Biomass was larger in riffle
areas on the first date, larger in macrophytes on the second
and about equal on the third date. From the fourth date,

2 September, to 6 October greater numbers of chironomid
larvae were associated with macrophyte beds. On 24 October
numbers of these larvae were still higher in macrophytes, but
the disparity between the two habitats was not as great as on
the previous dates. Chironomid biomass was higher in macro—
phyte beds from 2 September until the last date. Simuliids
showed a definite preference for macrophyte beds, both in
numbers and biomass. On all dates, except the second, numbers
were greater and biomass higher in macrophyte beds than in
riffles. In contrast to both chironomids and simuliids,
other dipteran larvae occur in higher numbers and larger bio-
mass in riffle areas; however, the disparity between numbers
of larvae in macrophytes and riffles was not great on 22 July
or 2 September.

The association of dipterans with macrophytes is obvious,
particularly with biomass. This association is due to
chironomid and simuliid larvae while other dipterans are
associated with riffles, both numbers and biomass. Maitland
(1966) found that in macrophytes, dipterans made up a higher

percentage of the fauna than in other habitats. Jonasson

18

(1948) found simuliid larvae in high concentrations in
Cladophora, particularly in early Spring and fall.

Caddisfly standing crop showed a definite relation to
substrate type, both numbers/m2 and biomass/m2 larger in the
bigger substrates in all except the first time periods
(Tables 1 and 2). In comparing macrophytic and riffle hab-
itats in this group, on the first and second dates a higher
number of individuals were associated with riffles (Table 5).
Concurrently, biomass was greater in macrophytes on the first
date but greater in riffles on the second date (Table 5).

On 22 July numbers in both habitats were nearly equal, but
biomass was greater in macrophytes. From 2 September to the
last date there were more individuals and a greater biomass
present in macrophytes than in riffle areas.

Although standing crop numbers of caddisflies showed
variation in relation to substrate for the first three time
periods, from.TP4 until the last more occurred in the larger
substrates. Relationship of biomass is obvious, in all
except the first time period, with more biomass being in
larger substrates. Pennak and Van Gerpen (1947) compared
numerical standing crops of three substrate types and found
more caddisflies associated with the larger stones. Sprules
(1947) found a similar relationship. However, Scott (1958)
found the densest populations on medium-sized stones. An
important factor causing differences between the two investi-

gations could be attributed to the presence of moss and algae

19

cover on particular sizes of stone resulting in a microhabitat
utilized by certain Species (e.g., members of the families
Hydropsychidae, Philopotomidae, Psychomyidae) (Percival and
Whitehead, 1929; Scott, 1958). Another factor that would
influence the relation to substrate type is movement of the
larvae. Scott noted that several species migrated from gravel
to larger stones upon pupation. Cummins (1964a) studied sub-
strate relations in two Pychopsyche Species. He showed that
one species during early larval periods was associated with
Silt bottom habitats, then migrated to gravel-pebble sub-
strates in the terminal instar. The other species Showed no
changes in substrate association as maturation occurred.
Standing crops of caddisflies, numbers and biomass,
follow the same pattern as mayflies and dipterans in relation
to plants; very little difference between the two habitats
in early summer, much higher in plants during late summer and
fall. When plants died off in late October, both habitats
became nearly equal. From observations it was determined
that utilization of macrophytes as a habitat was almost en-
tirely due to Hydropsyghe larvae. This association of
Hydropsyche larvae with macrophytes was noted by Jonasson
(1948), large populations being built up in Elodea beds during

the summer. Minckley (1965) observed that Hydropsyche larvae

 

avoided Myriophyllum beds in pool areas when there was little

or no current.

20

The caddisfly g, borealis showed a similar relation to

size of substrate type as did the group as a whole. TP; had
more individuals and a higher biomass associated with smaller
substrates. There was only one sample representing large
substrates in TPg and this did not contain any Specimens.
In TPs and TP4 there were more larvae in larger substrates
whereas biomass was greater in the smaller substrate in TPa
and greater in the larger substrates in TP4. The TP5 biomass
and numbers were smaller in smaller substrates. In the last
four time periods more nymphs and greater biomasses were
associated with larger substrates. Thus, H, borealis
seemingly demonstrates an affinity for larger substrates,
both in numbers and biomass. Cummins and Lauff (1970) studied
selectivity of substrate of this species in a laboratory
situation and found that there was a tendency to select the
largest substrate (16 mm). They noted that the larvae en-
countered locomotory problems on finer substrates but were
quite mobile on Silted substrates. Cummins and Lauff con-
cluded from their study that substrate size is of secondary
influence on micro-habitat selections and that food organisms
are probably of prime importance. However, a selection of
substrate may be made by the adult female while ovipositing
as it is known that many Species submerge to accomplish this
(Pennak, 1955).

Growth of macrophytes seemingly influences the distribu-

tion of H, borealis; more larvae were associated with riffles

21

than macrophyte beds on all dates except the last (Table 5).
Biomass was also larger in riffles in all cases except 22
July. No larvae occurred in the sample from macrophytes on
16 September. This association with riffles is in contrast
to the caddisfly group as a whole. These larvae, in contrast
to the majority of the larvae found in macrophytes, build
stone cases and are attached to rocks. It is possible that
adverse conditions arise from deposition of silt and detrital
material in macrophytes.

Numbers of beetle larvae/m2 demonstrated no consistent
relation to substrate type (Table 1). More larvae were associ-
ated with large substrate at TP; and TP2, but at TP3 there
were more in small substrates. TP4 and TPS had more larvae
and a greater biomass associated with larger substrates.
Biomass and numbers were greater in small substrate at TPe
as well as TPa and TP9. At TP7 larger biomass and greater
numbers were associated with large substrate. Biomass being
greater in larger substrates while numbers are fewer, indi-
cates larger larvae inhabiting larger substrates. Maitland
(1966) found higher numbers of beetle larvae occurring in areas
of coarse gravel than in the larger stones, whereas Pennak
and Van Gerpen (1947) found more associated with rubble (i.e.,
large stones) than with coarse gravel.

Comparing numbers of beetle larvae in relation to macro-
phyte or riffle habitat shows that there were more larvae

associated with macrophytes on two dates, 8 July and

22

2 September; on all other dates higher numbers were associ-
ated with riffle habitat. On 25 June biomass was nearly equal
in the two types of habitats, but macrophytes had a little
higher biomass. On 8 July a higher biomass was associated
with macrophytes. Higher biomass was associated with riffles
on 22 July and 6 October; at the three other dates it was
associated with macrophytes. There is little difference
between plant and riffle habitats, which is similar to what
Maitland (1965) observed; numbers of beetle larvae in plants
were nearly equal to those in riffle areas. Frost (1942)
and Minckley (1965) found large numbers of beetle larvae,
mostly elmids, inhabiting moss which undoubtedly provides
microhabitats.

Water mites occurred in higher numbers in small sub-
strates at three time periods, TPl, TP3 and TPs (Table 1).
At all other periods there were higher numbers in large sub-
strates. Biomass showed a similar relation to substrate in
that it was higher in small substrates at TP; and TP3 but
associated with large substrates at all other periods (Table
2). Macrophytic habitat had a higher number of water mites
associated with it from 22 July to 6 October (Table 5), whereas
riffle habitat had more associated with it on the first two
and last dates. Large biomass was not consistently associated
with either habitat but alternated between the two types of

habitat (Table 5).

25

There is no relation of water mites to substrate during
the first three time periods, after which numbers and biomass
are larger in bigger substrates. There seems to be no effect
on standing crops of water mites by growth of macrophytes.
Maitland (1966) found more mites occurring in macrophytes and
among large stones than in other areas, and Frost (1942)
found large numbers inhabiting moss. Jonasson (1948) found
in areas adjacent to macrophytes that when the plants died
there was an influx of mites which apparently did not occur
here.

The first two time periods showed more stonefly nymphs
associated with larger substrates with more associated with
smaller substrates the next two periods. Concurrently there
was a larger biomass in small substrates at TP; and TP3 but
larger in large substrates at TP2 and TP4. At TP5 as well
as TPa there were more nymphs in large substrates. At TPe
numbers were nearly equal in the two types of substrates even
though there were a few more in smaller substrate. At TP7
and TP9 more nymphs were in small substrates. In contrasting
riffle and macrophytic habitats, higher numbers occurred in
riffles on 25 June, 22 July and 6 October, with more occurring
in macrophytes on the other dates. Biomass was nearly equal
in the two habitats on two dates, 22 July and 24 October,
greater in macrophytes on 8 July and 16 September and in the

riffle areas on the other three dates.

24

In this study little can be said in regard to substrate
relationships of stoneflies, undoubtedly due to small
numbers present in the stream. Also little can be said in
relation to the effect of macrophyte growth other than that
there is no apparent adverse effect on standing crops by macro-
phytes. However, several studies (Percival and Whitehead,
1929; Pennak and Van Gerpen, 1947) have found more stoneflies
in larger substrates, whereas Maitland (1966) found more
associated with gravel than in a mixture of large and small
particle sizes. Stoneflies have also been shown to utilize
plants as a habitat (Frost, 1942), with large numbers utiliz-
ing moss, but Minckley (1965) found more individuals in riffle
areas without moss or macrophytes than in those with plants.

Total numerical standing crop does not demonstrate a
definite association with substrate type, generally reflect-
ing the association of the major numerical group, dipterans
(Table 1). Standing crop measurements that have been made in
different substrate types in the past have usually been thought
of as a demonstration of production, being higher in a particu-
lar substrate type (Pennak and Van Gerpen, 1947). However,
these studies have usually been over a short period of time,
the summer, and have used numbers as the measure of production
instead of biomass. Present data Show that there is a definite
association of biomass to substrate type, larger at all except
the first time period in the bigger substrates (Table 2).

As mentioned previously, this is probably due to the growth of

 

25

moss and algae on some of the larger rocks diversifying the
habitat, leading to more areas to be inhabited, particularly
by larger dipteran (e.g., Tipulidae, Rhagionidae) and caddis-
fly larvae (e.g., Hydropsychidae).

An effect of macrophyte growth on total standing crop
in numbers and biomass is evident (Table 5). During the
early part of the growth phase of the macrophytes (May and
June) there seems to be no difference in standing crops of
invertebrates. However, when macrophyte standing crop is
high (August to October), there are higher numbers and larger
biomass of invertebrates in the plants. Growth of macrophytes
as it occurred in this investigation brought about changes in
the riffle habitat, changing current velocity and turbulence
which in turn caused deposition of detritus and inorganic
materials. Other studies indicate that in such a situation
there would also be a change in the macroinvertebrate associ-
ations, through changes in abundance of various groups, dis—
tribution and diversity (Chutter, 1969; Cole, in press). As
macrophyte standing crop decreased in fall, there was a removal
of deposited materials and a return to riffle conditions, and
this is indicated in the last collection date (Table 5).
Growth of macrophytes also presents an unoccupied habitat to
be colonized by drifting organisms and those that have a summer
generation. It seems noteworthy that the macrophytes were
colonized by groups of organisms that are noted for drifting

and inhabiting denuded areas: Simuliidae, Baetidae and

26

Hydropsychidae (Waters, 1966; Chutter, 1968). Annual plants
then act as a refugia for drifting organisms preventing the
loss due to drift as presupposed in Situations in which

drifting of organisms occurs.

Substrate and Food Manipulation

Previous discussion focused on the relationship between
macroinvertebrates and habitat types. However, other factors
have been investigated (e.g., food, temperature, current and
others) and have been shown to be important. One factor is
detritus, both allochthonous and autochthonous, acting as a
source of nutrition for primary consumers (Nelson and Scott,
1962; Hynes, 1965; Darnell, 1964; Minshall, G. W., 1967;
Egglishaw, 1964). Therefore, it was decided to manipulate
substrate and amount of detritus under natural conditions to
quantitatively estimate the influence and interaction of these
two factors on macroinvertebrate numbers. In an attempt to
eliminate current as a factor, an area of relatively constant
current and depth, varying between 0.12 m/sec and 0.28 m/sec
(0.4 ft/sec and 0.9 ft/sec), and 15 cm and 27 cm (6 inches
and 11 inches), respectively, was selected. Eighteen loca-

tions of about 0.27 m2

(4 ft2) were selected and the stream
bottom removed to a depth of about 25 cm (9 inches). This was
a 2 x 5 factorial analysis design. Gravel and rock were ob-

tained from a local gravel company and separated into large

and small substrate types (see Table 4 for analysis of two

Table 4.

27

Particle size distribution by weight of four
samples, two from each Size category,

from sub—

strates substituted in a riffle area of the Pine

River.

 

 

Particle Size

Large

 

Weight of Particle
Size in Grams

Weight of Particle
Size in Grams

 

 

range in mm Sample
1 2 1 2
16+ 558.9 518.8 --- ——-
16-8 15.9 65.6 254.9 505.1
8-4 6.5 48.2 197.2 60.4
4-2 0.7 19.6 20.0 11.6
2-1 0.8 17.5 1.6 1.0
1-0.5 1.2 16.2 1.8 0.4
0.5-0.25 5.1 17.0 5.6 0.6
0.25-0.125 0.8 2.5 0.6 0.2
0.125-0.065 0.1 0.4 —-- 0.05

 

 

 

 

 

28

samples of each type). Dried Potamogeton (three Species
that were found in the stream) was added at levels of about
121 g/m2 (11 g/fta), 484 g/m2(44 g/fta) and 847 g/m2 (77
g/fta). In July each sample was placed at random in the
stream according to a random numbers table and sampled with
the Petersen dredge in October. Samples were placed in
buckets, 10% formalin added and returned to the laboratory.
Samples were processed as those taken throughout the year
with the exception that a No. 60 mesh sieve was used and two
subsamples per sample were taken.

Numbers of ephemeropterans, chironomids (data on this
group was transformed to logs due to variance heterogeneity)
and coleopterans were Significantly different between sub-
strate types and food levels; more individuals in each group
were associated with small substrates (Tables 5 and 6).
Orthoganal contrasts (Table 5) Show that numerically there
were Significant differences between food levels within sub—
strate types, for ephemeropterans and chironomids only within
small substrates and for coleopterans in both substrate types.
Oligochaetes were significantly associated with substrates
(Table 5), but orthoganal contrasts Show that within smaller
substrates medium food level was different from high food
level. Other dipterans and trichopterans were associated
Significantly with food levels. Orthoganal contrasts show in
both grOUps that low food level was significantly different

from medium and high with large substrates, and in dipterans

29

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51

medium food level was significantly different from high within
small substrates. Thus, from the preceding and Table 6, it

is clear more individuals are associated with smaller sub-
strates and with low and medium food levels than with high

food levels. If there is no significant relationship, there

is this tendency of higher numbers to occur in small substrates
and in low and medium food levels.

Although there was no consistent numerical relationship
to substrate type in many of the groups, results of substrate
substitution are generally in contrast to the higher numbers
in larger substrates found in other studies. -Food manipula-
tion also resulted in data one might not expect. Nelson and
Scott (1962), Minshall, G. W. (1967), and Mackay (1969) have
attributed the majority of energy utilized by stream benthos
to allochthonous detritus, and Egglishaw (1964) found
that numbers were significantly related to the amount of
detritus present in a stream. He also found the same relation-
ship by placing trays containing various amounts of detritus
in the stream.

Differences in numerical relationships to substrate type
between substituted and undisturbed substrates may be due to
dissimilarities in physical complexity. Natural substrates
are a heterogeneous mixture of large and small particles with
larger particles having an algal or moss covering. Smaller
substrates are less heterogenous in makeup, no moss or algal

covering for insects to inhabit or large rocks present.

52

Substrates substituted were more homogeneous than natural
substrates; large ones consisted mostly of particle sizes
bigger than 16 mm, resulting in relatively large interstitial
spaces and not having algal or moss growths extensive enough
for insects to inhabit. Smaller substituted substrates would
reduce interstitial Space Size, in comparison to larger
substrates, allowing greater numbers of insects to inhabit
the area.

Large numbers of insects occurring in low and medium
food levels rather than in high food levels may have two
explanations. At high food levels there may be so much plant
material present as to result in formation of aggregates.
Therefore, material on the inside of the aggregate would be
relatively unavailable to macroinvertebrates as a food source
since the available surface area per unit weight of available
food is decreased. But with low and medium food levels plant
material is more diSpersed and offers a larger surface area
which insects can utilize. Another possibility is that at
high food levels interstitial oxygen can not be maintained due
to decomposition of plant material resulting in interstitial
oxygen concentrations below tolerance levels for stream macro-
invertebrates. Those macroinvertebrates found would,

therefore, inhabit the surface and not interstitial areas.

55

Seasonal Variations in Standing Crop

The life histories of aquatic insects include a wide
array of forms. Some have one brood a year, others several;
some Show rapid growth in fall and Spring with little during
summer or winter; others grow from fall through Spring; some
have overwintering eggs, and others have ova with a long period
of hatching or a very short one (Harker, 1955; Macan, 1957;
Scott, 1958; Hynes, 1961; Hartland-Rowe, 1964; Maitland, 1964.
1966; Minshall, J. N., 1967; Heiman and Knight, 1970; and
others). DeSpite differences in life history forms that
exist in macroinvertebrates, from the analysis of all samples
obtained from the Pine River through the year, general patterns
of standing crop in the various groups can be seen.

Mayflies show two periods of relatively low numbers and
biomass, late spring-early summer (May-June) and late summer,
5-19 August (Figure 1, Tables 7 and 8). The low biomass and
numbers in Spring would be expected following emergence of
Spring emerging Species. During spring, average weight/nymph
ranged from 0.05 mg to 0.05 mg, but during the low period of
late summer, average weight was smaller, ranging from 0.01 mg
to 0.05 mg. Highest standing crop of numbers occurred during
two periods, early fall (16 Sept.-1968) and spring (12 May
1969), whereas highest biomass occurred during Spring (11
April to 12 May 1969); average individual weight ranged from

0.02 mg to 0.05 mg and 0.16 mg to 0.79 mg, respectively.

54

Figure 1. Seasonal changes in average estimate of
standing crop, numbers/m2 and biomass (g/ma),
of various groups from a riffle area of the
Pine River.

 

55

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40

The peak in numbers on 8 July 1968 is believed to be an arti-
fact because earlier collections gave estimates of biomass
and numbers which are believed to be too low.

From the preceding an overall picture of the changes of
the mayfly fauna with seasons may be deduced. In Spring,
emergence results in recruitment of many small nymphs; however,
since there are still large individuals present, average
weight/individual is maintained at a moderate level through
most of the summer. The majority of mayflies in Michigan's
trout streams have emerged by late August (Leonard and Leonard,
1962) at which time there are very few large nymphs in the
stream; nearly all occur in the egg stage or as relatively
small nymphs. As fall progresses biomass and numbers increase
with growth and hatching of dormant eggs.

Maitland (1966) found that mayflies were most abundant in
May to August and decreased throughout fall and winter. In
a productive stream studied by Egglishaw and Mackay (1967)
higher numbers of nymphs occurred during the winter months,
but no significant changes were observed in two relatively
sterile streams during the year. Comparisons among different
authors as done here suffers because of differing methods
(see Jonasson, 1955, and Macan, 1958, for a review of sampling
methods) and differing objectives. But despite this, com-
parisons of the general results can be made and perhaps some
conclusions drawn. In both of these studies the kicking method

was used, catching the floating invertebrates in large meshed

41

nets. The present study used a fine meshed screen which re-
tained many of the very smallest nymphs or larvae. It is
therefore believed that collections in the present study
give a more accurate description of the changes in the fauna.

Highest numerical standing crop of dipteran larvae
occurred in late November, 1968, with another peak occurring
in mid-April, 1969 (Figure 1, Table 7). However, biomass was
largest in early Spring with a lesser peak in late fall.
Lowest numbers were found in late summer (19 August) and late
Spring-early summer (7 June). Biomass was also low at these
times. Minckley (1965) found seasonal changes in abundance
of dipteran larvae, but time of maximum abundance varied with
habitat which changed as he progressed downstream. Maitland
(1966) found the greatest numbers occurring in summer which
undoubtedly is a reflection of his use of a large meshed
screen in collections.

When the order is divided into chironomids, simuliids
and all other dipterans, the trends in biomass, numbers and
average individual weight are similar (Figure 1, Tables 7 and
8), However, it is not surprising that the seasonal varia-
tion of the order as a whole reflects that of the chironomids,
the dominant group. Seasonal changes in chironomid larvae have
been noted by other authors. -Egglishaw and Mackay (1967)
in studying a productive stream, found peak numbers in June
and July with lows in late fall and late winter-early Spring.

Pupae occurred from May to October, but in higher numbers in

42

May, June and July. Allen (1951) found peak numbers in mid-
winter with pupae present at all times. In one area on the
River Susaa Jonasson (1948) found maximum numbers in spring
due to newly hatched and overwintering larvae, with numbers
decreasing appreciably in succeeding months. He found a
smaller peak in numbers during late summer with lows occurring
in fall and winter. At another area on the river he found
that numbers increased from spring to late summer, followed
by an appreciable decline. In the present study, peak numbers
of chironomids occurred in late fall and early Spring. Indi—
vidual dipterans in late fall averaged 0.01 mg each, whereas
in early spring they averaged 0.02 mg, indicating that the
chironomid fauna as a whole consists of larger individuals
which leads to highest biomass at this time. No pupae were
present in late fall collections, whereas in early spring
(11-25 April 1969) 1% to 2% of the chironomids collected were
pupae. During the summer less than 1% were pupae.

Simuliid larvae are well-known for their patchy distribu-
tion and a tendency to drift which results in extreme fluctua-
tions in numbers present in collections (Chutter, 1968;
Ulfstrand, 1968). Perhaps, though, a general description of
standing crops can be made. Maximum numbers and biomass
occurred during early summer (25 June to 22 July 1968 and 25
June 1969). This is undoubtedly from hatching of overwinter-
ing eggs and growth of larvae (Ulfstrand, 1968). There was

another peak in fall (16 September 1968) and at these two

45

peaks average individual weight ranged from 0.01 mg to 0.05
mg. There were minimums during late summer and early Spring
with larvae averaging 0.15 mg to 0.89 mg each. This may be
partially due to sampling error. Pupae made up from 0.2% to
1% of the total p0pulation on collections prior to these low
periods with only a few or none recorded at other times, thus
indicating emergence and reproduction responsible for the lows.
Frost (1942) observed a Similar distribution of numerical
standing crop in her study. Allen (1951) found that pupae
were most abundant during the same seasons observed in this
study but found no seasonal changes in larval abundance.
Jonasson (1948) found high numbers of larvae in the spring
but very few until fall when they were again abundant.

The majority of other dipteran larvae collected were large
specimens of the families Rhagionidae, Empedidae, and Tipulidae
with Dolichopodidae and Tabanidae taken in fewer numbers.

Small larvae of the family Heleidae were also taken. Taken
as a group these larvae demonstrated a low in numbers in late
summer (19 August 1968) and late Spring (12 May 1969) (Figure
1, Table 7). Biomass showed a low at two periods, late
summer (19 August 1968) and late Spring-early summer (25 June
to 24 July 1968) (Figure 1, Table 8). Numbers increased on
25 June 1969 then stabilized, whereas biomass decreased.
These trends are undoubtedly due to emergence of larvae and

recruitment of young.

44

There were four major families represented in trichop-
tera: Hydropsychidae, Helicopsychidae, Glossosomatidae
(Hydropsyche, Helicopsyche and Glossosoma, respectively) and
Limnephilidae, with the latter occurring less frequently than
the first three, while those of other families occurred in-
frequently. Caddisflies, numbers and biomass, showed several
periods of maximum and minimum (Figure 2, Tables 1 and 2).
But the low in both numbers and biomass in late fall (24
October 1968) may be due to sampling bias as biomass seems to
be increasing prior to a winter decrease, and the trend in
numbers is from a high in September to a winter low.

Average weight/individual and the percentage of pupae in
the population showed seasonal trends. Percentage pupae in
summer 1968 increased from 2% at 25 June to a high of 10%»on
5 August after which there was a decrease until none were
present on 6 October. Average weight/individual varied from
0.10 mg to 0.20 mg and dropped in early fall to 0.08 mg (16
September). Average weight then increased as fall progressed
to a high of 0.58 mg on 29 November. By 15 March 1969 this
had dropped to 0.25 mg and to 0.19 mg by 11 April at which
time less than one percent of the population was pupae.
Average weight increased to a high of 0.75 mg by 12 May then
decreased to a low of 0.21 mg on 24 June. After the start of
pupation in April the percentage of pupae increased to a high

of 12%lon 7 June then decreased to 1% on 24 June.

45

Figure 2. Seasonal changes in average estimate of
standing crop, numbers/m2 and biomass (g/m?),
of various groups from a riffle area of the
Pine River.

46

 

 

 

 

 

 

 

 

 

 

 

Figure 2

47

From the above, a general seasonal cycle may be in-
ferred for trichopterans as a whole. Biomass and numbers
are highest in spring prior to emergence due to gains in
weight following winter senesence and the hatching of over-
wintering eggs. Emergence continues through the summer due
to those species which emerge late and species that are
multivoltine. As fall progresses there is less emergence
and growth occurs leading to a high in biomass and numbers
in fall. rNumbers and biomass decrease due to winter mortal-
ity, and as temperatures increase at the end of winter,
growth of larvae resumes and overwintering eggs hatch.
Seasonal variations in trichopterans have been noted
by other authors. Frost (1942) and Hynes (1961) found a
steady decrease in numbers as winter progressed to lows in
late winter and early spring, with highest numbers occurring
from summer to fall. .Jonasson (1948) found no marked seasonal
variation but noted largest numbers occurring from January
to May. Minckley (1965) noted that in riffle areas there
were periods of high populations, but these were different
at various stations in the stream. But all highs occurred
between January and May. Allen (1951) found that in the
families Hydropsychidae and Rhyacophilidae average weight
-varied similarly to the variations noted in the present study:
smallest in late summer-early fall and highest in late winter-
early Spring. Scott (1958) found that there was a common
seasonal pattern to all Species he studied, a summer minimum

and a winter maximum.

48

Data were Obtained for an individual species of tri-
chopteran, Helicopsyche borealis (Figure 2, Table 7). Unlike
the order as a whole, maximum numbers occurred in August 1968
with a decline to a low in late winter with a smaller maximum
occurring in Spring. Maximum biomass occurred in early
summer, highest during June and July in both 1968 and 1969.
Percentage pupae and average weight/individual varies seasonal-
ly. Average weight decreased from 0.49 mg on 25 June 1968 to
0.52 mg on 22 July, whereas percentage pupae in the population
increased from 45% to 95%. Pupae were present in the collec-
tion on 2 September and 24 October, being less than one per-
cent of the population, and absent until Spring collections.
Average weight increased from 0.01 mg on 5.August to 0.11 mg
on 29 November then decreased to a low average weight of 0.05
mg on 11 April 1969. From this low, average weight increased
to a high of 0.50 mg on 24 June. Percentage pupae increased
from 1% on 25 April-1969 to 25% on 24 June.

The life history of g, borealis seemingly then is annual
with two broods present. Emergence begins in late spring
reaching a peak in early summer, resulting in a peak recruit-
ment of young larvae in late summer. Ross (1944) states that
there apparently is a continuous succession of generations,
emergence occurring from May to September. This could coin-
cide with embryonic development lasting between 9 and 25 days
for trichoptera (Scott, 1958). Perhaps some larvae are pro-

duced in spring, grow and emerge in the fall, producing ova.

49

Mortality of larvae occurs through winter. Delayed hatching
probably occurs in those ova produced in fall giving another
period of recruitment and reduction of average individual
weight along with the resumption of growth in Spring.

The majority of the beetles collected were of the family
Elmidae. Members of Psephenidae were collected only peri-
odically. Therefore, seasonal variation in standing crops
is mostly a reflection of elmid life histories. Maximum
biomass and numbers occurred in late winter after which there
was a decline (Figure 2, Tables 1 and 2). The extreme low
in numbers on 6 October may be due to sampling error as the
trend from the beginning of collections to winter was toward
an increase in numbers. Pupation in both of these families
occurs on the shores of the streams (Pennak, 1955; Leech and
Chandler, 1956). Therefore, only adults and larvae were
collected. Adult percentage of the population between 25
June and 22 July ranged from 2.5% to 5% and decreased as
summer progressed to fall. No adults were collected from 6
October until the following spring when adults again began to
appear in the population because of pupation, numbers in-
creasing as spring progressed.

Average weight/individual increased due to growth from
0.05 mg on 25 June 1968 to 0.10 mg on 19 August, then de-
creased to 0.05 mg on 16 September probably because of recruit-
ment of young and emergence of adults. Increase in average

weight then occurred as young grew to a high on 29 November

50

of 0.11 mg which was maintained until 15 March 1969, after
which average weight decreased to a low of 0.02 mg on 25 May,
probably due to recruitment of overwintering young, and then
increased to 0.06 mg on the last date, 24.June.

These two families of beetles, Elmidae and Psephenidae,
are thought to have a two-year life cycle (Pennak, 1955;
Leech and Chandler, 1956) and the data presented here seem—
ingly support this thought. Perhaps, then, seasonal changes
occur in the following manner. Pupation results in high
numbers of adults in early summer with the production of ova
which have an extended period of hatching, resulting in a
gradual increase in larvae through summer. Concurrently,
those larvae which will not pupate until the following spring
grow, and as the number of young larvae increase through late
summer, there is a decrease in average weight/individual and
biomass. Growth of the population as a whole leads to an in-
crease in biomass through late fall. (With the advent of Spring,
mature larvae leave the stream to pupate leading to a decrease
in average weight, numbers and biomass. Frost (1942) found
that higher numbers of adults occurred during the winter at
a time when larvae were lowest in numbers. Highest number of
larvae in her study were found in July.

Although there are fluctuations in standing crops (bio—
mass and numbers), there are obvious trends in standing crops
of water mites (Figure 2, Tables 1 and 2). There is an in-

crease from an early summer low to peak numbers and biomass in

51

fall. Following this there is a winter decrease, an increase
in spring, followed by an apparent decrease in early summer.
Maitland (1966) found the highest numbers of water mites in
his samples from May to October, whereas Jonasson (1948)
found the highest numbers in late winter and early Spring;
Jonasson attributed this to the migrations of individuals
from decaying vegetation along the stream to the stony sub-
strates. There is some confusion concerning whether water
mites reproduce throughout the year or during late spring or
early winter (Pennak, 1955). Present data seem to support
the latter.

Stoneflies of the genus Taeniopteryx made up the majority
of plecopterans collected, with Pteronarcys taken periodically.
Nymphs did not occur in high numbers in this study which leads
to obvious sampling errors in estimating standing crops
through the year, and makes it very difficult to discuss sea-
sonal changes. Spring and early summer emergence occurred in
Pteronarcys, but this should not have caused the extreme low
on 19 August 1968 as the majority of stoneflies collected
were Taeniopteryx. This low may be due to two factors: one
is sampling as previously mentioned. Secondly, it has been
observed that benthic organisms may go as deep as 50 cm
(Coleman and Hynes, 1970), presumably to escape particular
rigors of the environment (Maitland, 1964). Possibly summer
temperatures are a form of "rigor" for Taeniopteryx, a winter

emerger (Frison, 1955); large numbers of adults were observed

52

on 15 March 1969. AS temperatures decrease in the fall,
Taenigpteryx emerges from the substrate and resumes growth
leading to a high biomass in the winter. Emergence occurs
in late winter resulting in a low biomass, but oviposition
leads to an increase in numbers during spring.

In this study macroinvertebrates taken as a whole
demonstrated fluctuations seasonally with peak numbers in late
fall-early winter and a lesser maximum in Spring; the largest
biomass occurs in early spring before emergence commences.
Changes in numbers reflect the changes in dipteran larvae
as these were the predominant group numerically. For example,
the extreme low on 19 August was due to few numbers of dip-
teran larvae present. The low estimate of both biomass and
numbers on the first collection date, 25 June 1968, is not
entirely a reflection of the fauna. Because it occurred in
every group on this date, I feel this low is due to sampling
error. The decline through winter may not be due entirely
to winter mortality. Babcock (1954a, b) points out that
insects may be found as deep as 12 cm and Coleman and Hynes
(1970) have Shown that insects may occur as deep as 50 cm in
the substrate. It may be that insects seek the lower strata
of the substrate to escape rigors of winter. As temperatures
increase with the advent of Spring, they return to the sur-
face and, with hatching of overwintering eggs and resumption
of growth, there is a spring increase in both numbers and

biomass. In retrospect then, a general pattern of change may

55

be described. Lowest numbers and biomass are found in early
summer, both increasing through fall. Both decrease due to
winter mortality and possible vertical movement downward,
but with warmer temperatures numbers again increase, due to
hatching and a vertical movement upward, and biomass reaches
a maximum before emergence.

The seasonal change observed in the present study is not
entirely in accordance with that found by other authors.
Maitland (1964) found peak numbers and biomass during summer
months; however, he stated that the streams he studied were
subject to extreme winter conditions and spates which led to
low numbers during winter. Although flooding was observed in
the present study, particularly during spring, there was no
scouring of the bottom, which iS a situation that has been
shown to be an important factor to stream benthos (Minckley,
1965; Maitland, 1964, 1966). Egglishaw and Mackay (1967)
found a maximum biomass in spring, but maximum numbers occurred
in July and December through March. Jonasson (1948) found
that maximum numbers occurred in Spring. All of the above
authors used large meshed screens which allow the loss of
smaller nymphs, whereas I used a fine meshed screen which
retained small nymphs and led to better characterization of

the changes in numbers and biomass.

54

Annual Production Estimate

In past years the production of aquatic plants and
fish has been measured. Recent years have seen an increase
in the measurement of production of invertebrates but limited
to single species and then to those that demonstrate certain
types of life histories (see Mann, 1969, and Waters, 1969,
for reviews). Presently there is particular emphasis on
attempts to determine production of entire benthic faunas and
by a means which is fairly simple. Hynes and Coleman (1968)
have attempted to do this (see Fager, 1969, and Hamilton,
1969, for modifications and criticisms of the technique) by
using length measurements of the fauna collected over a
year's time. Waters (1969) has recently reviewed the litera-
ture concerning turnover ratio in freshwater invertebrates
and found that it ranged from 2.5 to 5, averaging 5.5, which
is comparable to the turnover ratios which Hynes and Coleman
found with their method.

Although the present study was not designed to obtain an
accurate estimate of production, perhaps a gross estimate may
be obtained by using waters' assumed constant, 5.5. It was
felt that the results might be compared to the production
estimate of Hynes and Coleman (1968) as well as eStimates
obtained in future studies. Average ash-free dry weight was
2.52 g. Multiplying by the constant gives an average of 8.0

g/ma/yr. But, as Waters points out, in a fauna which is

55

dominated by multivoltine Species this ratio would be higher

by two-or-threefold. Since the fauna in this study undoubtedly
consists primarily of multivoltine species, mayflies, dip-
terans, and various Species caddisflies, it seems reasonable

to assume that the turnover ratio would be near seven (which
assumes an average of two generations a year) in which case
production of ash-free dry weight would be 17.7 g/ma/yr. It
was determined that dry weight is about 6.7 times greater than
ash-free dry weight. Egglishaw and Mackay (1967) found that
wet weight of insects averaged 5.5 times dry weight. Together
these two factors give an estimate of wet weight as being 57
times greater than ash-free dry weight. Multiplying this
factor by the estimate of ash-free dry weight gives a production
estimate 654 g/mg/yr. This river is high in nutrient and
primary production (Tesar, 1970) and is comparable in secondary
production to that of 620 g/m2 of another hardwater stream as
determined by Hynes and Coleman (1968). Although Waters'
turnover ratio is highly speculative, it would seem that an
estimate of 654 g/mZ/yr may be in the right order of magni-
tude. This is also a method which is much more Simple and

less time consuming than the one proposed by Hynes and Coleman.

Observations on Sphaerium striatinum
M

Three species of fingernail clams were represented in the

collections: Sphaerium striatinum, Pisidium compressum and

56

g. fallax. Pisidium occurred infrequently; therefore, only
.§2 striatinum will be considered in the following discussion.

Clams were picked from the decanted material which re-
mained in the Sieves and from the remaining gravel, then stored
in 75% ethyl alcohol. Numbers and ash-free dry weight were
expressed as for the other invertebrates. Ash-free dry weight
was determined in the same manner as for the other inverte-
brates. Ash-free dry weight was determined in the same manner
as for the other invertebrates. For growth studies the length
of each clam was taken to the nearest 0.2 mm with an ocular
micrometer. Those too large for the microscope's field were
measured to the nearest 0.2 mm with a pair of dividers.

It was observed that after ashing young within the adults
maintained their form and rigidity. Therefore, to determine
numbers of young produced and time of reproduction, adults
and young that they contained were measured from 25 June to
2 September 1968. After 16 September until the termination of
the study the young were counted after ashing but no measure-

ments taken.

Standing Crop and Habitat

Average number/m? was high on the first collection date,
25 June 1968, after which there was a decline followed by an
increase on 5 August to the prior level (Figure 4, Table 9).
Biomass and numbers increased to a high on 22 July but then

decreased to an extreme low on 19 August. This decrease is

57

Figure 5. Seasonal changes in average estimate of total
standing crop, numbers/m2 and biomass (g/m?),
from a riffle area of the Pine River.

Figure 4. Seasonal changes in standing crop of Sphaerium
striatinum, numbers/m? and biomass (g/mf), in
a riffle area of the Pine River.

58

 

 

 

 

 

   

 

 

 

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60

undoubtedly due to sampling error as both numbers and biomass
increased next sampling, reaching high in September. Through
fall and winter there was a decrease in numbers and biomass,
probably because of winter mortality, reaching a low on 11
April 1969. From this time the tendency of both was to in-
crease, probably from spring reproduction. The extreme low
on 25-May is again probably due to sampling error as the
tendency from 25 March until termination of the study was to
increase.

Biomass and numbers were associated with smaller sub—
strates from TP; to TPs (Table 10) and during these periods
the disparity between the average standing crOps associated
with the two substrate types was generally great. At TPe
and TP7 numbers and biomass were higher in larger substrates,
but at the last two periods both parameters were again associ-
ated with smaller substrates. It should be pointed out that
there is extensive overlap of standard deviations in each time
period, thus the differences between standing crops of small
and large substrates are insignificant statistically. However,
perhaps the trend is meaningful in itself.

From Table 11 it can be seen that both highest numbers
and largest biomass were associated with macrophyte and riffle
habitats an equal number of times, both about equal on the
last date. Even though there was only one sample obtained
from macrophyte beds on each date, compared with means of

samples from riffle habitats, I think the comparisons give an

61

 

 

 

 

 

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65

estimate of what effect macrophytes have on sphaeriid dis-
tributions.

The general trends in standing crops shown here, high
during spring, summer and early fall with a general decline
through winter months, are Similar to those found by Foster
(1952). Although he sampled approximately monthly, no com-
parison can be-made with regard to standing crops as he did
not sample a constant area.

The two extreme lows that occurred in the present study
may be caused by high waters or sampling error. Minckley
(1965) and Maitland.(1964, 1966) have discussed the effect
of SpateS in streams which leads to a reduction of the fauna
by washing them away and destroying them. However, in the
present case, even though water levels were about six inches
higher than normal, I believe the lows are due to sampling
because of the later return to prior levels, even though water
levels were still high. Gale (1969) studied standing crops
of sphaeriids in the Mississippi River from June to December,
.fi. striatinum being present in substantial numbers. Highest
numbers and biomass occurred in August, approximately 5,000/m?
and 50 g/m? dry weight. Highest numbers in the present study
were 1,005/m? during September. Highest biomass also occurred
in September, 5.54 g/m? ash-free dry weight. If it is assumed
the conversion factor of 6.7 to convert ash-free dry weight

to dry weight is valid, an estimate here of 24 g/m? is given.

64

Herrington (1962) indicates that this Species, most
common of the genus, has a wide tolerance of habitat type,
being present in sand, sandy-gravel, and muds of creeks,
rivers, and lakes. In the present study the smaller substrate
types seem to be preferred, generally having higher average
standing crops. Gale (1969) comments that substrate type
did not appear to greatly affect the abundance of sphaeriids
(two species) except that fewer occurred in substrates of
bare rock, gravel, or hard clay. It seems plausible that
the relation to substrate type is due to physical effect.
Larger substrate types contain rocks which occupy Space that
would be available if smaller rocks or sand were present.
This would also be a possible reason for the differences
between standing crops of Gale's study (where substrate con-
sisted of sandy silt) and the standing crops of the present
study.

There seems to be no adverse effects on g, striatinum

 

distribution by extensive summer growth of macrophytes. This
might be expected in a species which has a wide tolerance of
habitats. This is in contrast to Gale's (1969) report that
areas associated with vegetation generally supported low
sphaeriid populations. However, it must be pointed out that
he was dealing with very large standing crops, and areas of
vegetation in his study may still have yielded populations

equal to or greater than were found in the present study.

65

Growth and Reproduction

From Figure 5 it seems that the majority of the young
are extruded when they are 5.6 mm to 5.8 mm in length; few
smaller free-living young were found in the collections.
Length measurements of young still contained by adults showed
very few 4.0 mm or larger. The percentage distributions in Fflj\
Figure 5 also show that a bimodal curve is present in a number 2 "&

of samples, 8 July to 5 August, 2 September to 16 September

1968, and 25 May to 24 June 1969. However, no growth can be

 

interpreted from these distributions as there are no changes E
in various size groups through the year. Numerous individuals
reached a Size of between 10 mm and 11 mm, with some being as
large as 15.5 mm.

Table 12 Shows the size of adult and number of young
contained. The largest number of adults examined contained
two young, with a substantial number containing one. A few
adults contained 5 and 4 young. Smallest adults containing
young from 25 July to 2 September were 7.4 mm and of those
equal to or greater than this size the percentage containing
young is shown in Table 15. It can be seen that the greatest
percentage carrying young occurs from late fall to spring
with the least occurring during summer and early fall.

Minimum size of free-living young and maximum sizes of
young still within adults coincide; thus young are released
when they reach a Size of 5.6 to 4.0 mm. This is in accordance

with Foster's (1952) findings. However, maximum size of adults

66

Figure 5. Length frequency distributions for collections
of Sphaerium striatinum, by date, from the
Pine River.

67

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70

in Foster's study was Smaller; the largest specimen was 10
mm with the majority of the largest individuals being 9-9.5
mm.
Gilmore (1917) stated that the majority of adult
lg. striatinum contained two young, one in each pouch, with a
few containing four. Foster (1952) obtained Similar results F“?K
but also found a few adults with one or three young, as 9 '”4

fbund in the present study, and concluded this was due to

I, :V'AN'Ku":

the recent extrusion of young. The bimodal curves (Figure 5)

44"”

 

seem to suggest that these Sphaeriids live two years and E.
from this and Table 12 the majority of reproduction and
nurturing of young seems to occur during colder months with
the majority of young being released in Spring, summer, and
fall. Monk (1928) reached a similar conclusion with this
species. Foster arrived at different conclusions; finding

a bimodal curve in size distributions, he attempted to Show
that it was due to periods of maximum extrusion of young dur-
ing spring, summer and fall. It should be pointed out that
these three studies were conducted in two divergent habitats,
Foster's work in an oxbow lake and Monk's and the present
study in streams, and the differences in conclusions about the
life history of the clam may be derived from differences in

life history response to habitat type.

GENERAL CONCLUSIONS

The effect of substrate Size, macrophyte growth and
detritus distribution was demonstrated in the present study.
As a whole the benthic fauna does not demonstrate a definite
association with either small or large substrates numerically,
but biomass is higher in larger substrate Sizes. Standing
crop, biomass and numbers, is higher in macrophyte beds than
in riffles when they are dense but the habitats are Similar
during early growth phase of the plants and in late fall when
they have died back. Substrate-food substitution experiment
showed that the majority of the groups were related to low
and medium food levels and small substrate Sizes. Although
macro- or microdistribution of invertebrates may be related
to a particular factor, the interaction of many factors is
undoubtedly the most important aspect of the problem.

Most benthic invertebrate studies seem to disregard the
problem of sampling technique, and in this case it was random.
A stratified random sampling design, according to at least
three substrate sizes and macrophyte beds, would have alle—
viated this problem and led to less variation in estimates

of standing crops.

71

72

Coarse screens are normally utilized in benthic studies
and miss many of the younger larvae which were obtained in
this study by the use of a fine meshed screen. Compared to
other studies the present study obtained substantially higher
estimates of numbers of macroinvertebrates/m3, the highest
being 116,000; thus a more accurate estimate of standing

crops and seasonal changes has been given. (

[J

LITERATURE CITED

LITERATURE CITED

Allen, K. R., 1951. The Horokiwi Stream. A study of a
trout population. N. Z. Marine Dept. Fish Bull.
10, 251 pp.

Anderson, R. O., 1959. A modified flotation technique for
sorting bottom fauna samples. Limnol. and Oceanogr.,
4:225-225.

Babcock, R. M., 1954a. Studies of the benthic fauna in
tributaries of the Kavling River, southern Sweden.
Inst. Freshwater Res., Drottningholm, Rept., 55(1955):
21-57 0

, 1954b. Comparative studies in the populations of
streams. Inst. Freshwater Res., Drottningholm, Rept.,
55(1955):58-50.

 

Chutter, F. M., 1968. On the ecology of the fauna of stones
in the current in a South African river supporting a
very large Simulium (Diptera) population. J. Applied
Ecol., 5:551-561.

, 1969. The effects of silt and sand on the inverte-
brate fauna of streams and rivers. Hydrobiol., 54:
57-77.

Cole, Richard A., 1971. Variations in community response
to enrichment of a spring—tempered stream. Limnol. and
Oceanogr. In Press.

Coleman, M. J., and H. B. N. Hynes, 1970. The vertical
distribution of the invertebrate fauna in the bed of a
stream. Limnol. and Oceanogr., 15:51-40.

Cummins, K. W., 1962. An evaluation of some techniques for
the collection and analysis of benthic samples with
special emphasis on lotic waters. Amer. Midl. Nat.,
67:477-504.

, 1964a. Factors limiting the microdistribution of
the caddisfly larvae Pycnopsyche lepida (Hagen) and
Pycnopsyche guttifer (Walker) in a Michigan stream.
Ecol. Monogr., 54:271-295.

75

74

Cummins, K. W., 1964b. A review of stream ecology with
special emphasis on organism-substrate relationships.
In: Organisms-Substrate Relationships in Streams.
K. W. Cummins, C. A. Tryon, Jr., and R. T. Hartman
eds., pp. 2-51. Edwards Bros., Inc., Ann Arbor, Mich.

Cummins, K. W., and G. H. Lauff, 1969. The influence of
substrate particle Size on the microdistribution of
stream macrobenthos. Hydrobiol., 54:145-181.

Darnell, R. M., 1964. Organic detritus in relation to
secondary production in aquatic communities. Verh. Int.

Denhalm, S. C., 1958. A limnological investigation of the
West Fork and Common Branch of White River. Invest.
Ind. Lakes & Streams, 1:17-71.

Egglishaw, H. J., 1964. The distributional relationships
between the bottom fauna and plant detritus in streams.

Egglishaw, H. J., and D. W. Mackay, 1967. A survey of the
bottom fauna of streams in the Scottish Highlands.
Part III. Seasonal changes in the fauna of 5 streams.
Hydrobioln 50:505-554.

Eisenberg, R. M., 1970. The role of food in the regulation
of the pond snail, Lymnaece elodes. Ecol. 51:680-684.

Eriksen, C. H., 1965. A method for obtaining intestitial
water from shallow aquatic substrates and determining
the oxygen concentration. Ecol., 44:191-195.

Fager, E. W., 1969. Production of stream benthos: a critique
of the method of assessment proposed by Hynes and
Coleman (1968). Limnol. and Oceanogr., 14:766-770.

Foster, T. D., 1952. Observations on the life history of a
fingernail Shell of the genus Sphaerium. J. Morph.,
55:475-496.

Frison, T. H., 1955. The stoneflies, or Plecoptera, of
Illinois. Bull. Ill. Nat. Hist. Surv., 20:1-471.

Frost, W. E., 1942. River Liffey Survey. IV. The fauna of
the submerged "masses" in an acid and an alkaline
water. Proc. R. Irish Acad., R. 47:295-569.

75

Gale, W. F., 1969. Bottom fauna of Pool 19, Mississippi
River, with emphasis on the life history of the finger—
nail clam, Sphaerium transversum. Unpublished Ph.D.
thesis, Iowa State University.

Hamilton, A. L., 1969. On estimating annual production.
Limnol. and Oceanogr., 14:771-782.

Harker, J. E., 1955. An investigation of the mayfly fauna
of the Lanceshire stream. J. Animal Ecol., 22:1-15.

Hartland-Rowe, R., 1964. Factors influencing the life-
histories of some stream insects in Alberta. Verh. Int.

Heiman, D. R., and A. W. Knight, 1970. Studies on growth and
development of the stonefly, Paragnetina media Walker
(Plecoptera: Perlidae). Amer. Midl. Nat., 84:274—278.

Herrington, H. B., 1962. A revision of the Sphaeriidae of
North America (Mollusca: Pelecypoda). Misc. Publ. Mus.
Zool., Univ. Mich., No. 118, 74 pp.

Hynes, H. B. N., 1961. The invertebrate fauna of a Welsh
mountain stream. Arch. Hydrobiol., 57:544-588.

, 1965. Imported organic matter and secondary pro—
ductivity in streams. Proc. 16 Internat. Congr. Zool.,
5:524-529.

Hynes, H. B. N., and M. J. Coleman, 1968. A Simple method
of assessing the annual production of stream benthos.
Limnol. and Oceanogr., 15:569-575.

Jonasson, P. M., 1948. Quantitative studies of the bottom
fauna. In: Berg, K., Biological studies on the River
Susaa. Folia Limnol. Scand., 4:204-285.

, 1955. The efficiency of sieving techniques for
sampling freshwater bottom fauna. Oikos., 6:185—207.

'Leech, H. B., and H. P. Chandler, 1956. Aquatic Coleoptera.
In: Aquatic insects of California with keys to North
American genera and California species. R. L. Usinger
ed., pp. 295-571. Univ. Calif. Press, Berkeley and
Los Angeles.

Leonard, J. W., and F. A. Leonard, 1962. Mayflies of
Michigan trout streams. Cranbrook Inst. Sci. Bull.,
45:1-159.

76

Linduska, J. P., 1942. Bottom type as a factor influencing
the local distribution of mayfly nymphs. Can. Entom.,
74:26-50.

Macan, T. T., 1957. The life-histories and migrations of
the Ephemeroptera in a stony stream. Trans. Soc.
Brit. Ent., 12:129-156.

, 1958. Methods of sampling the bottom fauna in
stony streams, Mitt. Int. Ver. Limnol., No. 8, 21 pp.

Mackay, R. J., 1969. Aquatic insect communities of a small
stream on Mont St. Hilair, Quebec. J. Fish Res. Ed.
Canada, 26:1157-1185.

Mackay, R. J., and J. Kalff, 1969. Seasonal variation in
standing crop and species diversity of insect communi-
ties in a small Quebec stream. Ecol., 50:101—109.

Maitland, P. S., 1964. Quantitative studies on the inverte-
brate fauna of sandy and stony substrates in the River
Endrick, Scotland. Proc. R. Soc. Edingurgh., B. 68:
277-501.‘

, 1966. Studies on Loch Lomond. II. The Fauna of
the River Endrick. Blackie and Son Limited, London.

Mann, K. H., 1969. Dynamics of Aquatic Ecosystems. Advan.
Ecol. Res., 6:1-81.

Minckley, W. L., 1965. The ecology of a spring stream,
Doe Run, Meade County, Kentucky. Wildl. Monogr., 11:
1-124.

Minshall, G. W., 1967. Role of allochthonous detritus in the
trophic structure of a woodland springbrook community.
Ecol., 48:159-149.

Minshall, J. N., 1967. Life history and ecology of Epeorus
pleuralis (Banks( (Ephemeroptera: Heptageniidae).
Amer. Midl. Nat., 78:569-588.

Monk, C. R., 1928. The anatomy and life history of a fresh-
water mollusc of the genus Sphaerium. J. Morph. and
Physiol., 45:475-505.

Pennak, R. W., 1955. Fresh-water invertebrates of the United
States. Ronald Press, New York, 769 pp.

77

Pennak, R. W. and E. D. Van Gerpen, 1947. Bottom fauna pro-
duction and physical nature of the substrate in a
northern Colorado trout stream. Ecol., 28:42-48.

Percival, E., and H. Whitehead, 1929. A quantitative study
of the bottom fauna of some types of stream bed. J.
Ecol., 17:285-514.

, 1950. Biological survey of the River Wharfe. II.
Report on the invertebrate fauna, J. Ecol., 18:286-502.

Ross, H. H., 1944. The Caddisflies, or Trichoptera, of
Illinois. Bull. Ill. Nat. Hist. Surv., 25:1-526.

Scott, D., 1958. Ecological studies on the trichoptera of
the River Dean, Cheshire, Arch. fur Hydrobiol., 54:
540-592.

Sprulee, W. M., 1947. An ecological investigation of stream
insects in Algonquin Pard, Ontario. U. of Toronto
Stud., Biol. Ser. No. 56.

Tesar, Frank J., 1970. Primary production in a central
Michigan stream. Unpublished Masters' Thesis, Michigan
State University.

Thorup, J., 1965. Growth and life-cycle of invertebrates
from Danish springs. Hydrobiol., 22:55-84.

Ulfstrand, S., 1967. Microdistribution of benthic species
(Ephemeroptera, Plecoptera, Trichoptera, Diptera:
Simuliidae) in Lapland streams. Oikos, 18:295-510.

, 1968. Benthic animal communities in a Lapland
stream. A field study with particular reference to
Ephemeroptera, Plecoptera, Trichoptera, and Diptera
(Simuliidae). Oikos, suppl. 10, 116 pp.

Waters, T. F., 1969. The turnover ratio in production ecology
of freshwater invertebrates. Amer. Nat., 105:175—185.

Wene, G., and E. L. Wickliff, 1940. Modification of stream
bottom and its effects on the insect fauna. Canad.
Ento., 72:151-155.

Whitehead, H., 1955. An ecological study of the invertebrate
fauna of the chalk stream near Great Driffield,
Yorkshire. J. Animal Ecol., 4:58-78.

 

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