RIFFLE COMMUNITY STRUCTURE IN EIGHT NORTHERN CALIFORNIA STREAMS

by

Jonathan J. Lee

A Thesis

Presented to

The Faculty of Humboldt State University

In Partial Fulfillment

of the Requirements for the Degree

Master of Arts

May, 1990 RIFFLE INSECT COMMUNITY STRUCTURE IN EIGHT NORTHERN CALIFORNIA STREAMS

by

Jonathan Lee

We certify that we have read this study and that it conforms to acceptable standards of scholarly presentation and is fully acceptable, in scope and quality, as a thesis for the degree of Master of Arts.

Major Professor

Approved by the Graduate Dean ACKNOWLEDGEMENTS

I gratefully thank Dr. David Lauck for his help in the field, in the laboratory and fοr having a bit of patience. I also thank Dr. Richard Hurley (Humboldt State University) and

Dr. Ole Saether (University of Bergen) fοr their help in reviewing some of the taxonomic determinations.

Also, thanks to my committee members; Drs. Kenneth Lang,

David Lauck, Mike Messler and Terry Roelofs for their critical review and constructive suggestions leading towards the completion of this thesis.

iii ABSTRACT

Riffle sections of eight streams in Northern California were sampled for aquatic using a kick net. Eleven chemical and physical stream parameters were measured at each riffle sampled. Biological data was analyzed using Simpsons diversity index and Chandlers Biotic Score index. Calculated values were plotted against measured chemical/physical parameters. The resulting scattergrams were examined for relationships between chemical/physical data and the indices values. No relationships were observed.

Biological samples were inspected for trends not apparent in the scattergrams. Insect community structure varied among streams and seasonally within streams. The ten most abundant taxa from each sample were plotted by percent abundance and their cumulative percentage was totaled for each sample. The resultant graphs carry more information on community structure than the diversity or biotic indices. A qualified community structure and a diversity component can be observed.

Streams are separated into "headwater" and middle order streams based primarily on degrees slope and annual temperature range. Notes are made on insect taxa typical of these streams types. Recommendations are made for regional expansion of Chandlers Biotic Score table and further taxonomic and life history research, particularly within the dipteran family .

iv TABLE OF CONTENTS

List of Tables vi List of Figures vii Introduction 1 Study Area 5 Materials and Methods 14 Results 20 Notes on taxa within each order 31 31 Ephemeroptera 34 Trichoptera 37 Coleoptera. 42 Diptera 45 Odonata 51 Lepidoptera 52 52 Discussion 126 Conclusion 141

Literature Cited 144 Personal Communication 154 Appendix A. Taxonomic literature used 155 Appendix B. List of insect taxa collected 160 Appendix C. Insect diversity and biotic indices values vs. chemical and physical stream parameters 168

V LIST OF TABLES

Table Page 1. Chandlers Biotic Score Index 19 2. Water chemistry values at date of sample. 22 3. Stream physical values at time of sampling 24 4. Simpson diversity values, Chandler Biotic Score values, and number of taxa in each sample 28 5. Insect taxa collected (Hatchet Creek) 54 Insect taxa collected (Little Cow Creek) 60 Insect taxa collected (Clear Creek) 65 Insect taxa collected (Weaver Creek) 70 Insect taxa collected (Canyon Creek) 76 Insect taxa collected (Bidden Creek) 80 Insect taxa collected (East Fork Willow Creek) 84 Insect taxa collected (North Fork Mad River) 89

vi LIST OF FIGURES

Figure page

1. Study area 6 2. Percent substrate composition 27 3(a) - 10(g) Percentage of ten most abundant taxa 3. Hatchet Creek 94 4. Little Cow Creek 98 5. Clear Creek 102 6. Weaver Creek 106 7. Canyon Creek 110 8. Bidden Creek 114 9. East Fork Willow Creek 118 10. North Fork Mad River 122 11. Comparison of samples with similar diversity values but dissimilar community structure 132 12(a-b) Seasonal community structure (a) Hatchet Creek 135 (b) Little Cow Creek 135

13(a) Diversity values vs. alkalinity values 168 (b) Diversity values vs. total hardness values 168 (c) Diversity values vs. conductivity values 169 (d) Diversity values vs. pH values 169 (e)Mean diversity vs. mean slope 170

(f)Mean diversity vs. mean substrate composition 170

vii LIST OF FIGURES (cont.)

Figure Page 13(g) Diversity values vs. surface velocity values. ...171 (h) Diversity values vs. temperature values 171 (i) Diversity values vs. turbidity values 172 14(a) Biotic Score values vs. alkalinity values 173 (b) Biotic Score values vs. total hardness values 173 (c) Biotic Score values vs. conductivity values 174 (d) Biotic Score values vs. pH values 174 (e) Mean Biotic Score vs. stream slope 175 (f) Mean Biotic Score vs. mean substrate composition 175 (g) Biotic Score values vs. surface velocity values 176 (h) Biotic Score values vs. temperature values 176 (i) Biotic Score values vs. turbidity values 177

viii INTRODUCTION

Aquatic insects have long been used in attempts to evaluate the relative health of stream ecosystems. Factors contributing to the suitability of insects for stream evaluation include abundance in most lotic systems, a general lack of mobility and uni- or bi-voltinism. Recent stream perturbations of short duration should be indicated by the insect fauna even after physical or chemical stream characteristics have returned to pre-perturbed conditions. An unperturbed stream community would typically have relatively few common species and many species represented by relatively few individuals (Wilhm 1971). Empirical indices based upon the concept of community diversity have become popular in the assessment of environmental stress (Helliwell 1978). Diversity indices attempt to condense data on species abundance within a community into a single number (Washington 1984). Community structure would be reflected by the calculated value. Diversity indices analyses in stream studies have traditionally investigated the effect of organic waste on the community structure, however, no assumptions are made regarding the nature of the stress (Helliwell 1986). Biotic indices are also used in assessing stream water quality (Helliwell 1986). Biotic indices are based on the concept of "indicator organisms", organisms sensitive to or

1 2 tolerant of various environmental conditions. Like diversity indices, values are expressed as numerical units. Unlike diversity indices, community structure is not necessarily represented in biotic indices. Values calculated are usually based on organism tolerance to organic enrichment although values may reflect physical factors such as elevated water temperatures (Helliwell 1986). Biotic indices, however, should be a reliable tool in ranking a streams health using regional indices (Hilsenhoff 1977). An alternate approach to investigating the interaction of environmental conditions and stream community structure is to graphically illustrate the ten most abundant taxa in a benthic invertebrate sample by relative percentage. The data express an evenness component of diversity and an "indicator" community (Wilhm 1970). The resultant graph does not "neatly package" a benthic sample but expresses more information than a single value would and is not as cumbersome as a list of the entire benthos from the sample. Insect community diversity is influenced by a number of physical habitat and/or nutritional resource factors. Important physical factors controlling distribution and abundance include substrate (Cummins and Lauff 1969; Hynes 1970; Kimble and Wesche 1975; Minshall and Minshall 1977; Tolkamp 1980; Reice 1983), temperature (Armitage 1961; Hynes 1970; Vannote 1973; Vannote and Sweeney 1980; Ward and Stanford 1982; Townsend et al. 1987) and current velocity 3

(Hynes 1970; Kimble and Wesche 1975; Minshall and Minshall 1977). Nutritional research has included studies dealing with trophic relationships (Cummins 1973), nutritional ecosystem dynamics (Vannote et al. 1980; Knight and Bottorff 1984) and species and community nutrition, food resources and growth (Anderson and Cummins 1979; Naiman and Sedell 1980; Hawkins 1982; Hawkins et al. 1982; Hawkins 1986; Behmer and Hawkins 1986).

Dissolved substances in running waters are also considered to be important factors controlling stream benthos distribution (Hynes 1970). International Hydrological Decade- World Health Organization (1978) includes dissolved minerals, pH and anion-cation concentrations as baseline data for "water quality" surveys. Townsend et al. (1983,1987) found pH strongly influenced community structure in British streams. Winget and Mangum (1979) used alkalinity and sulfate concentrations as limiting chemical parameters when calculating tolerance quotients for stream invertebrates. Krueger and Waters (1983) found a positive correlation between alkalinity and macroinvertebrate production values in three Minnesota streams. United States Environmental Protection Agency documents have reviewed the literature and compiled checklists for certain chemical and physical parameters at which Chironomidae (Diptera) (Beck 1977), Ephemeroptera (Hubbard and Peters 1978), Plecoptera (Surdick and Gaufin 1978) and Trichoptera (Harris and Lawrence 1978) 4 larvae have been found. In general, there is a paucity of published literature comparing benthic invertebrate community structure and physicochemical parameters of several streams using similar methodologies. Ideally, results would indicate individual taxa and benthic communities associated with measured environmental factors. The present study was undertaken in order to determine if correlations exist between stream benthos and selected physical and chemical data from several streams. Simpsons (1949) Diversity Index was used to interpret community structure and Chandlers (1970) Biotic Score was utilized to investigate the score systems merit in ranking selected streams using selected parameters. The above indices were rated highly by Washington (1984) and Helliwell (1986) when compared to similar indices. Community structure was also examined by graphic illustration of the ten most abundant taxa. STUDY AREA

Eight streams were selected for this study. Selection criteria included geographically separated watersheds, feasibility of year round collecting and easy access from California State Highway 299 (Figure 1). The region is characterized by wet winters and dry summers. Average annual precipitation ranges from 76 to 152 cm. Average annual air temperature approximates 13.3 degrees C. August has the highest average air temperature (26.5' C. at Clear Creek) and January the coldest (0' C. at Hatchet Creek) (Climatological Data 1987). The principle riparian vegetation at each stream site was White Alder (Alnus rhombifolia) and Willow (Salix spp

NORTH FORK MAD RIVER The North Fork of the Mad River is a 4th order stream entering the Mad River at Korbel, California. The North Fork drains an area of 104.9 square kilometers with elevations ranging from 24 to 884 meters. The Franciscan formation dominates the geology of the watershed, lithologically represented by massive graywacke and minor amounts of platy, dark gray shale, thin bedded chert and glaucophane schist (Geologic Atlas of California 1969). Primary vegetation in the watershed includes Redwood (Sequoia sempivirens), Douglas Fir (Pseodotsuga menziesii),

5 6

Figure 2. Map of study area. 7

California Laurel (Umbelluria californica), Madrone (Arbutus menziesii), Willow, Tan Oak (Lithocarpus densiflora) and Blue Blossom (Caenotus thyrsiflorus). Soils of the drainage area belong to the Hugo and Melbourne series and are of moderate erosion hazard (Soil-Vegetation Map 1960a). The study area was located at Camp Bauer, one kilometer north of Maple Creek Road at an elevation of 49 meters. Stream slope at the study site was 1 degree.

EAST FORK WILLOW CREEK The East Fork of Willow Creek is a 3rd order stream located approximately 8.5 kilometers west of Willow Creek, California. It drains an area of 30.82 square kilometers. Elevations range from 472 to 1463 meters. Headwaters originate in mesozoic ultrabasic intrusive rock lithologically characterized by Peridotite, minor pyroxenite and largely serpentinized diurite. The main geologic types in the drainage area are undivided triassic and paleozoic rocks consisting of quartz mica schist, granitic phyllite and metachert. Characteristic soils in the watershed include a Clallum- Hugo-Holland families association featuring a high erosion hazard. A plant community of mixed conifer, Tan Oak, Madrone, Douglas Fir and White Fir (Abres concolor) dominates the watershed (Soil-Vegetation Map 1960b). The study site was located at East Fork campground, one 8 kilometer south of the stream confluence with the mainstem of Willow Creek. The sample site was at an elevation of 488 meters and a slope of six degrees.

BIDDEN CREEK A tributary of the Trinity River, Bidden Creek is a 2nd order stream located 28.5 kilometers east of Willow Creek on California State Highway 299. Bidden Creek drains an area of 3.23 square kilometers. Elevations range from 300 to 900 meters. Undivided triassic and paleozoic rocks characterize the geology of the headwaters. The main drainage features mesozoic granitic horneblende diurite. Soil and vegetation information for the watershed was unavailable. The study site was located at the juncture of Bidden Creek and Highway 299 at an elevation of 320 meters. The section of stream at and immediately above the sample site was a cascade with a slope of 29 degees.

CANYON CREEK Canyon Creek is a 4th order stream which empties into the Trinity River at Junction City, California. Stream elevations range from 450 to 2300 meters. Canyon Creek drains an area of 167.84 square kilometers. Canyon Creek lies in the Central Metamorphic subprovince. The primary metamorphic rock unit is Salmon 9

Horneblende Schist. Lithologic features include amphibolite horneblende schist, amphibolite hornfels and amphibolite migmatite. The headwaters lie in mesozoic granitic rock, mainly horneblende diurite. Also within the watershed is the Rhonerville Formation contributing gravel, sand and clay. Primary soils of lower Canyon Creek include Goulding Schist and Horseshoe series both of which exhibit moderate erosion hazard. Tailings and placer mine diggings occur along the stream. Dominant vegetation includes Canyon Oak (Quercus C. chrysolepsis), Oregon Oak (Q. g. garryazrna), Live

Oak (Q. wislenii frutescens), Douglas Fir, Digger Pine (Pinus sabiniana) and White Alder (Soil-Vegetation Map 1980). The collection site was located directly upstream from the highway 299 bridge at Junction City. Elevation at the study site was 450 meters and slope was 2 degrees.

WEAVER CREEK Weaver Creek is a Trinity River tributary running southeast through the town of Weaverville, California. A 4th order stream, Weaver Creek drains an area of 125 square kilometers with elevations ranging from 490 to 2000 meters. Headwaters originate in Pre-silurian metavolcanic rock of the Salmon Horneblende Schist geological unit. The primary geological feature downstream is Oligocene non-marine sedimentary rock of the Weaverville formation. Lithologic features include fine gravel sandstone, shalt' sandstone, 10

sandy shale, lake beds, lignitic shale, lignite, tuff and coarse stream conglomerate. Pre-silurian metasedimentary rock of the Abrams micaschist geological unit occur further downstream. The dominant soil of the lower watershed is the Weaverville series which exhibits moderate erosion hazard. The lower Weaver Creek floodplain is primarily dredge tailings and placer mined areas. The dominant vegetation in the watershed includes Greenleaf Manzanita (Arctostaphylos p. patula), Whiteleaf Manzanita (A. viscida), Oregon Oak, Digger Pine and Western Yellow Pine (Pinus ponderosa) (Soil- Vegetation Map 1975). The sample site was located 9 kilometers southeast of Weaverville on highway 299. Elevation at the sample site was 500 meters with a slope of 1 degree.

CLEAR CREEK Clear Creek is a 4th order stream which flows into Whiskeytown Reservoir. The stream drains an area of 298 square kilometers. Stream elevations range from 366 to 1400 meters.

The primary geological unit of the Clear Creek watershed is Mississippian marine sedimentary and metasedimentary rocks of the Bragdon formation. Lithologic features include dark greenish-gray to black, thinly bedded meta-shale, interstratified metamorphosed siltstone, sandstone, grit and 11 conglomerate in the upper part. Features of the lower watershed include metamorphosed local thin bedded chert, rhyolitic tuff and malfic volcanic rocks. Featured to a lesser extent are Devonian and pre-Devonian (?) metavolcanic rocks of the Copley Greenstone unit. Dominant soil series for the watershed is a Maymen-Goulding-Stonyford-Los Gatos association exhibiting a moderate to high erosion hazard. The Clear Creek flood plain features gold dredge tailings and mined Horseshoe series soils. The chaparral community is dominated by Brewer Oak (Quercus garryanna breweri), Shrub Interior Live Oak (Q. wislizenii frutescens), Western Mountain Mahogany (Cercocarpus betuloides), California Black Oak (Q. kelloggii) and Manzanita (Arctostaphylos spp.) (Soil- Vegetation Map 1973, 1975). The study site was located 4.5 kilometers south of French Gulch at highway 299. Study site elevation was 390 meters and slope was 1 degree.

LITTLE COW CREEK Little Cow Creek is a 3rd order tributary of Cow Creek. Little Cow Creek flows southwest from an elevation of 1768 meters to 171 meters in Shasta County, California and drains an area of 157 square kilometer. Headwaters originate in Pliocene volcanic basaltic rocks. Geology of the main drainage area includes Eocene non- marine sedimentary rocks of the Montgomery Creek formation, 12

Triassic marine sedimentary and metasedimentary rocks and Jurassic and/or Triassic metavolcanic rocks. The Windy and Cohasset soil series dominate the headwaters of Little Cow Creek (Soil-vegetation Map 1965a). Further soil/vegetation information was unavailable. The sample site was 34 kilometers east of Redding at an elevation of 347 meters. Stream slope at the study site was 1 degree.

HATCHET CREEK Hatchet Creek originates on Hatchet Mountain (Shasta Co.) at an elevation of 1707 meters. Hatchet Creek empties into the Pit River at an elevation of 366 meters. This 3rd order stream drains an area of 65 square kilometers. Hatchet Creek passes under highway 299, 19 kilometers west of Burney, California. The principle geological unit in the drainage area is Pliocene volcanic basaltic rocks. Lithologic features include black to gray flows of aphanatic to medium grained olivine basalt, andesitic basalt, pyroxene basalt and local thin interbedded mudflows. Nanny and Cohasset soil series dominate the watershed and are of slight erosion hazard. Scrub Tan-oak (Lithocarpus densiflora), Deerbush ceanothus (Caenothus interegerrimus), White fir, Sugar pine (Pinus lambertiana), Incense cedar (Libocedrus decurrens), Douglas fir and Pacific dogwood 13

(Cornus nuttalii), make up the forest community within the watershed (Soil-Vegetation Map 1965b). The sampling site was located at Moose Camp Road approximately one kilometer from highway 299. Elevation at the study site was 1146 meters and the slope was 6 degrees. MATERIALS AND METHODS

Insect collections and water quality parameter measurements were to be conducted at approximately bi-monthly intervals for one year beginning November 1983. High rainfall and the resultant road closures in the winter of 1984 prevented a collecting trip for that time period. A collecting trip was added in the winter 1985 to cover this gap in data.

BIOLOGICAL SAMPLING AND PROCESSING

Sampling was conducted in the riffle habitat at each stream. Riffles were chosen due to their greater faunal richness than other stream sections (Hynes 1970). Benthic collections were made in the thalweg of the riffle or as close to the thalweg (centerline of the riffle) as possible during periods of high flow. Sites within the thalweg were selected by eye. "Kick" sampling (reviewed by Resh 1979) was determined to be the most feasible sampling method . An "A" frame kick net was used. Surface area of the face was 1,422.5 square centimeters with a maximum bag mesh size of 1.6 square millimeters. Dr. David Lauck operated the kick net at each site. Substrate was disturbed to approximately eight centimeters. Each sampling approximated one minute.

14 15

The total contents of the net were emptied to a jar of 80% ethanol for laboratory processing. Using white enamel trays, insects were hand picked from the gravel and debris. When two passes were made with a hand held microscope (10X objective) without finding any insects the sample was considered "clean". Insects were keyed to the lowest possible taxonomic level using a stereomicroscope. General taxonomic keys used were Usinger (1956) and Merritt and Cummins (1984). Keys used for taxa within orders are listed in Appendix A. Larvae of the dipteran family Chironomidae were processed by clearing the head capsule in 10% KOH solution for 24 hours and mounting head capsule and body under separate cover slips in Hoyer's solution. Larval determinations were made using a compound microscope (40- 1000x). The primary taxonomic reference for chironomid determinations was Wiederholm (ed.)(1983). Where there was a question of identification in early instars or a lack of regional keys a conservative approach was taken placing the specimen to the higher taxonomic level. Specimens that keyed to a particular genus but did not fit the description for that genus were assigned a question mark (?) after the generic name. Those that did not key to a statement in the dichotomous key were assigned "near" before the name of the closest taxon in the key. Specimens whose characters were significantly different from the taxonomic 16 key or those for which regional keys were unavailable to the species level were assigned an arabic numeral. Taxa collected are listed in Appendix B.

PHYSICAL/CHEMICAL SAMPLING

Physical and chemical stream parameters were measured in the riffles sampled at the same time as the biological sampling. Water chemistry measurements made at the stream site included dissolved oxygen, measured with a portable YSI model dissolved oxygen meter, and pH and nitrate, measured using a Hach water analysis kit. Other chemical measurements were performed in the laboratory. Water samples were taken in glass jars and transported on ice for analysis within 24 hours. Alkalinity (a measure of hydroxide, carbonate and bicarbonate concentrations) and total hardness (a measure of the total concentration of calcium and magnesium ions) were analyzed using Hach reagents and a 100 ml. titration buret. A YSI model 33 S-C-T meter was used to measure conductivity (an approximation of total ionic content). Depth was measured at each site as a range due to the heterogeneous substrate. Velocity was measured using a surface float as described by Lind (1979). Temperatures were taken to the nearest degree Celsius using a standard thermometer. Turbidity measurements were made in the laboratory with a Junior III Spectrophotometer. Slope, 17 substrate and base width were measured on the September 1984 sampling. A Relascope® was used to measure slope in degrees. Riffle substrate composition was determined by measuring boulder and cobble dimensions and estimating percent surface area within a square meter area of stream bottom. Smaller fractions were measured by collecting a substrate sample and wet screening with standardized screens (16mm, 8mm, 4mm, 2mm, lmm, 0.5mm, and 0.25mm.). A volumetric determination was made for each size class down to < .25 mm. A mean psi value was calculated for each stream substrate using relative abundance of size categories.

DATA ANALYSIS

The Simpson Diversity Index was used to determine diversity per sample. Diversity was calculated (from Pielou 1969) :

Where Ν = number of individuals in jth species

Ν = total number of individuals in sample

Comparisons of biotic index values were made between samples using Chandlers Biotic Score (1970). Chandlers Biotic Score is a biotic index which uses a "score" system of assigning 18 numerical values to stream invertebrates. Taxa sensitive to polluted conditions are assigned higher scores with increased abundance, while taxa tolerant to polluted conditions receive lower scores for increased abundance (Table 1). The Simpson Diversity values and Biotic "score" values were plotted against physical/chemical parameters using Macintosh Cricket Graphics software. The resulting scattergrams were examined for relationships between physical/chemical parameters and diversity and biotic index values. 19

Table 1. "Score" system for aquatic invertebrates used in Chandler's Biotic Index (Chandler 1970).

Abundance in standard sample

Groups present in sample Present Few Common Abundant Very Abundant 1-2 3-10 11-50 51-100 100+

POlNTS SCORED Planaria alpina Each species of Taeniopterygidae, Perlidae, Perlodidae, lsoperlidae, Chloroperlidae 90 94 98 99 100 Each species of , Capniidae, Nemouridae (excluding Amphinemoura) 84 89 94 97 98 Each species of Ephemeroptera (excluding Baetis) 79 84 90 94 97 Each species of cased caddis Megaloptera 75 80 86 91 94 Each species of Anchylus 7 0 75 82 87 91 - Rhyacophila (Trichoptera) 65 70 77 83 88 Genera Dicranota, Limnophora 60 65 72 78 84 Genus Simulium 56 61 67 73 75 Genera of Coleoptera, Nematoda 51 55 61 66 72 - Amphinemoura (Plecoptera) 47 50 54 58 63 - Baetis (Ephemeroptera) 44 46 48 50 52 - Gammarus 40 40 40 40 40 Each species of uncased caddis (excluding Rhyacophila) 38 36 35 33 31 Each species of Tricladida (excluding Ρ. alpina) 35 33 31 29 25 Genera of Hydracarina 32 30 28 25 21 Each species of Mollusca (excluding Anchylus) 30 28 25 22 1 8 - Chironomids (excluding riparius) 28 25 21 1 8 1 5 Each species of Glossiphonia 26 23 20 1 6 1 3 Each species of Asellus 25 22 1 8 1 4 1 0 Each species of Leech (excluding Glossiphonia, Haemopsis) 24 20 1 6 1 2 8 - Haemopsis 23 1 9 1 5 1 0 7 - Tubifex sp. 22 1 8 1 3 1 2 9 - C. riparius 21 17 12 7 4 - Nais 20 16 10 6 2 Each species of air breathing species 1 9 1 5 9 5 1 No life 0 RESULTS

Chemical parameters measured were similar for each stream sampled with the exception of Bidden Creek which showed a higher concentration of dissolved substances (Table 2). All stream sites had a seasonal rise in pH and dissolved substance concentration during the summer. Dissolved oxygen concentrations were recorded at saturation for each sample site and therefore will not be considered further as a potential limiting factor. Nitrate concentrations, determined on the September 1984 sampling, showed only trace levels at each stream site and will not be considered as a limiting factor. Water temperature and surface velocity show an inverse relationship attributable to seasonal precipitation. Values measured for temperature, surface velocity, turbidity and slope are listed in Table 3. Percent substrate composition, also similar at each stream sampled, is illustrated in Figure 2. Diversity values obtained were compared with physical/chemical parameters measured. The resulting scattergrams (Appendix C) do not suggest a relationship between diversity values and alkalinity, total hardness, conductivity, pH, temperature or turbidity. Hatchet and Bidden Creeks had the highest average diversity values and the steepest slopes of the streams studied. Diversities did not, however, vary with slope in

20 21 the remaining streams studied (Appendix C, Figure 13(e)). Hatchet and Bidden Creeks also had the largest mean substrate size of the streams sampled (Figure 2). Canyon Creek, with the third largest mean substrate size, also had the lowest mean diversity value (Appendix C, Figure 13(f)). A positive relationship between substrate composition and insect diversity is not suggested by Figure 13(f). A relationship between surface water velocity and diversity values is suggested by Figure 13(g). The lowest diversity values occurred at high water velocities. A strong relationship is not suggested by the remaining points, however. The data do not suggest a strong relationship between the calculated biotic index values and the measured physical/chemical parameters (Appendix C). Lower biotic "scores" did coincide with higher chemical parameter values. Bidden Creek had the lowest mean biotic index values and also had the highest concentration of dissolved substance of the streams studied. Simpson diversity values, Chandler biotic "score" values and number of taxa per sample were highest in Hatchet Creek (Table 4). Though high diversity values (› 0.9) were generally associated with relatively high biotic "scores" and number of taxa per sample this relationship did not always hold true (see Clear and Bidden Creeks, 11-26-83). 22

Table 2. Water chemistry values in eight Northern California streams measured at time of riffle benthos sampling. Alkalinity Conductivity Η Total Hardness (mg/1 as) (µmhos/cm3) (mg/1 as CaCO3) CaCo3 STREAM: (Sample date) HATCHET: 11-26-83 50 50 6.8 30 4-29-84 20 45 6.4 20 7-06-84 40 40 6.9 30 9-14-84 50 47 7.3 35 11-05-84 50 50 7.0 30 1-11-85 35 49 6.9 30 3-31-85 35 34 6.5 30

LITTLE COW: 11-26-83 50 83 6.8 30 4-29-84 40 60 6.5 40 7-06-84 90 68 8.0 110 9-14-84 80 91 8.0 55 11-05-84 80 118 7.5 65 1-11-85 50 91 7.0 50 3-31-85 45 60 6.6 50

CLEAR: 11-26-83 20 50 6.7 40 4-29-84 30 75 6.5 20 7-06-84 45 62 8.0 30 9-14-84 50 67 7.5 45 11-05-84 50 80 6.9 40 1-11-85 35 53 6.8 30 3-31-85 35 50 6.7 30

WEAVER: 11-26-83 70 90 6.8 50 4-29-84 60 90 6.7 50 7-11-84 75 96 7.8 70 9-14-84 120 124 8.2 100 11-05-84 100 132 7.8 80 1-11-85 75 98 7.8 65 3-31-85 65 78 6.9 65 23

Table 2. Water chemistry values in eight Northern California streams measured at time of riffle benthos sampling (cont.) .

Alkalinity Conductivity kΙ Total Hardness (mg/1 as) (µmhos/cm3) (mg/1 as CaCO3) CaCO3 STREAM: (sample date)

CANYON: 11-26-83 40 46 6.7 30 4-29-84 30 42 6.4 20 7-06-84 20 14 7.0 20 9-14-84 40 44 7.7 30 11-05-84 30 30 6.7 20 1-11-85 40 52 6.7 35 3-31-85 35 43 6.8 30

BIDDEN: 11-26-83 xx xx 6.8 xx 4-29-84 130 171 7.0 110 7-06-84 160 120 8.2 195 9-16-84 135 141 8.2 135 11-05-84 140 173 8.2 130 1-11-85 135 157 7.7 120 3-31-85 130 138 7.1 135

EAST WILLOW: 11-27-83 50 56 6.7 30 4-29-84 40 68 6.5 40 7-06-84 55 80 7.2 45 9-16-84 70 90 7.5 60 11-05-84 70 88 7.0 60 1-12-85 50 75 6.8 45 3-31-85 50 40 6.8 75

NORTH MAD: 11-27-83 20 40 6.5 20 5-17-84 50 60 6.7 40 7-12-84 50 85 6.8 35 9-16-84 60 92 7.7 60 11-07-84 30 45 6.7 30 1-12-85 35 60 6.9 35 4-04-85 50 35 6.8 30 24

Table 3. Physical measurements in eight Northern California streams at time of riffle benthos sampling. Slope Surface Velocity Temperature Turbidity (m/sec.) ('C) (T. U.) STREAM: (sample date)

RATCHET: 6' 11-26-83 .89 3.0 5.0 4-29-84 1.53 7.0 6.5 7-06-84 .91 12.0 5.7 9-14-84 .73 11.5 10.6 11-05-84 .73 5.0 8.0 1-11-85 1.00 1.5 11.5 3-31-85 .97 4.0 7.5

LITTLE COW:2' 11-26-83 .83 6.0 10.5 4-29-84 .78 12.0 19.0 7-06-84 .60 20.0 8.4 9-14-84 .73 19.0 11.2 11-05-84 .73 8.0 18.0 1-11-85 1.21 4.0 29.0 3-31-85 .92 8.0 120.0

CLEAR: 2 11-26-83 .73 7.0 6.0 4-29-84 1.12 14.0 12.0 7-06-84 .65 21.0 6.6 9-14-84 .65 21.0 11.0 11-05-84 .97 8.5 18.0 1-11-85 1.53 5.5 5.4 3-31-85 1.32 9.5 14.0

WEAVER: 2' 11-26-83 1.45 7.5 12.0 4-29-84 1.08 14.0 12.0 7-06-84 .62 21.0 6.8 9-14-84 .58 18.0 11.3 11-05-84 .97 9.8 19.0 1-11-85 1.04 5.5 15.0 3-31-85 1.38 11.0 185.0 25

Table 3. Physical measurements in eight Northern California streams at time of riffle benthos sampling (cont.). Slope Surface Velocity Temperature Turbidity (m/sec.) ('C) (T.U.) STREAM: (sample date)

CANYON: 2.5º 11-26-83 1.26 6.5 2.0 4-29-84 1.53 11.5 3.4 7-06-84 1.16 17.0 2.8 9-14-84 .76 18.0 3.2 11-05-84 1.53 8.2 5.0 1-11-85 1.38 5.0 4.9 3-31-85 1.38 10.0 4.0

BIDDEN: 29º 11-26-83 xx 9.5 xx 4-29-84 xx 11.5 7.2 7-06-84 xx 14.0 11.8 9-16-84 xx 13.0 10.9 11-05-84 xx 11.0 13.5 1-12-85 xx 10.0 36.0 3-31-85 xx 10.5 9.5

EAST WILLOW:5º 11-27-83 1.50 7.0 3.5 4-29-84 .69 8.0 6.3 7-06-84 .73 14.0 6.8 9-16-84 .97 13.0 2.3 11-05-84 .58 8.5 15.0 1-12-85 .60 4.5 6.0 3-31-85 .88 5.5 10.0

NORTH MAD: 1º 11-27-83 1.67 9.0 22.0 5-17-84 .89 11.0 8.0 7-12-84 .83 17.0 10.0 9-16-84 .73 18.5 5.0 11-07-84 1.40 9.0 70.0 1-12-85 1.61 6.5 27.5 4-04-85 1.38 10.0 54.0 26

Figure 2. Substrate composition of riffle in eight Northern California streams. Figure 2. Substrate composition of riffle in eight Northern California streams (cont.). 28

Table 4. Simpson diversity values, Chandler Biotic Score value: and number of taxa collected in each riffle benthos sample from eight Northern California streams.

Simpson Diversity Chandler Score Number Taxa STREAM: (Sample date)

HATCHET: 11-26-83 .9023 2898 50 4-29-84 .793 2902 45 7-06-84 .9373 3731 79 9-14-84 .9683 3708 76 11-05-84 .9223 3333 73 1-11-85 .9508 3754 73 3-31-85 .8643 3760 75

X .9055 3441 67 LITTLE COW: 11-26-83 .8796 1151 17 4-29-84 .8826 1903 38 7-06-84 .9234 2246 61 9-14-84 .709 1134 41 11-05-84 .8514 829 34 1-11-85 .867 1753 34 3-31-85 .8593 1713 32

X .8532 1533 37 CLEAR: 11-26-83 .9465 1888 47 4-29-84 .8826 1609 41 7-06-84 .9116 1962 48 9-14-84 .8448 1979 61 11-05-84 .7684 1919 45 1-11-85 .8136 1665 34 3-31-85 .874 2120 Α5

X .8631 1877 46 WEAVER: 11-26-83 .7471 1541 30 4-29-84 .8896 2533 49 7-06-84 .908 2124 43 9-14-84 .8757 2251 73 11-05-84 .8511 2136 54 1-11-85 .8509 2156 45 40 3-31-85 .9144 2571

X .8624 2187 48 29

Table 4. Simpson diversity values, Chandler Biotic Score values, and number of taxa collected in each riffle benthos sample from eight Northern California streams (cont.).

Simpson Diversity Chandler Score Number Taxa STREAM: (Sample date)

CANYON: 11-26-83 .8527 1806 28 4-29-84 .8238 1626 35 7-06-84 .8712 1787 36 9-14-84 .9085 2133 45 11-05-84 .4399 798 12 1-11-85 .8445 1759 30 3-31-85 .7933 2019

X .7906 1704 32 BIDDEN: 11-26-83 .9355 1055 20 4-29-84 .8704 1498 32 7-06-84 .8412 1236 28 9-16-84 .8888 1388 28 11-05-84 .8941 1641 36 1-11-85 .8649 1485 43 3-31-85 .8508 1804

X .8779 1444 33 EAST WILLOW: 11-27-83 .7036 741 11 4-29-84 .911 2413 48 7-06-84 .9431 2734 65 9-16-84 .7215 1690 32 11-05-84 .9147 1939 39 1-12-85 .9028 2782 44 3-31-85 .8514 2953 57

X .8497 2179 42 NORTH MAD: 11-27-83 .5256 287 5 5-17-84 .8266 1028 21 7-12-84 .866 2359 57 9-16-84 .9231 1615 47 11-07-84 .8565 1291 24 1-12-85 .8514 1650 28 4-04-85 .7937 2575 54

X .8061 1544 34 NOTES ON ΤΑΧΑ WITHIN EACH ORDER

Eight orders of insects were collected. As would be expected in the riffle habitat, Plecoptera, Ephemeroptera, Trichoptera and Diptera were the dominant taxa. The greatest number of taxa occurred in the Hatchet Creek samples as indicated in Tables 4 and 5.

PLECOPTERA (Stoneflies) Plecoptera richness was highest in the Hatchet Creek samples. The cool water temperature and heterogeneous substrate found in Hatchet Creek favors plecopteran richness (Hynes 1976) . The family Capniidae was represented in all streams except Bidden Creek. Specimens were collected primarily in the November and January samples. Capnids are winter/spring emergers. The timing of the life cycle prevents the larvae from exposure to warm temperatures, as is often the case with plecopterans (Hynes 1976). Unfortunately, without associated adults, larvae were not keyed past family. The Chloroperlidae were represented by six genera. Specimens were found in all streams sampled; however, they were not abundant in any of the collections. Fewer representatives of the family Leuctridae were found than any other plecopteran group. The monotypic species and augusta were among the

31 32 leuctrids collected. Determinations past family of other leuctrid specimen were not made. A hyporheic existence is suggested by the elongate, pale, mostly hairless larvae. As with the chloroperlids the hyporheic habitat results in under collecting by conventional methods (Hynes 1976). Eight taxa of the family Nemouridae were collected. Nemourids were common in samples from all streams with the exception of Little Cow and Clear Creeks. Malenka (probably californica) occurred in the greatest abundance. Zapada was also common and was represented by four species. The other nemourid genera were collected infrequently. Two genera of peltoperlids were collected. The family was represented only in Hatchet, Bidden and East Willow Creeks. Jewitt (1959) indicates peltoperlids are usually found in small streams of moderate flow and cool year round temperatures. Peltoperlids were found at the margins of these streams (not in the thalweg) during heavier flows suggesting lateral migration from areas of strong flow or pre- emergent behavior (Hynes 1976). The family Perlidae was found in all streams sampled. The ubiquitous Calineuria californica occurred in all streams and in most of the samples. Generally speaking Hesperoperla pacifica occurred in the larger, warmer streams while Doroneuria baumanni was present in the smaller, cooler streams. Exceptions were found in Little Cow and East Willow Creeks. Four late instar larvae of D. baumanni were 33 collected at Little Cow Creek in the April 1984 sample. Pre- emergent drifting from a small tributary could explain their occurrence, however Jewitt (1959) and Wilkinson (1986) found D.baumanni to emerge in the summer months. H. pacifica was collected on three sample dates in E. Willow Creek. It was also collected here by Wilkinson (1986). Though not abundant, the habitat here is suitable for H. pacifica. Claasenia sabulosa was found only in Canyon Creek. Specimens were collected on each sample date. Sorer (1987) did not find C. sabulosa in upstream samples and Allan (1982) found it in moderate numbers only at a site of the greatest width and discharge of the sites he collected. Canyon Creek was collected within 200 meters of its confluence with the Trinity River and was the largest stream collected. An exaggerated femoral and tibial fringe of hair was observed on the perlids collected at Hatchet Creek. What adaptive value it has and why it occurs only in Hatchet Creek is puzzling. It may allow for greater stability on the larger rock surfaces within the current. The family Perlodidae was the most diverse of the plecopteran families collected with more than ten species in ten genera. The most common genus was Isoperla. Unfortunately keys to accurately separate larvae have not been developed. Isoperla was collected in all streams except Bidden Creek. Chernokrilus sp. was the sole perlodid collected at Bidden. Oroperla barbara was collected only at 34

Hatchet Creek. O. barbara is reported only from the Sierra Nevada by Jewitt (1956) and may be restricted to higher elevation streams. Although not collected in large numbers the family Pteronarcidae was collected from each stream except E. Willow Creek. Pteronarcys californica was the more common of the two species collected. P. princeps was positively determined only from Hatchet Creek samples. The family Taeniopterygidae was represented by Taenionema. Abundant only in Hatchet Creek this species was also collected from Weaver Creek and the North Fork Mad River. Instar development between November 1984 and March 1985 suggests rapid winter growth in Hatchet Creek.

EPHEMEROPTERA () Ephemeropterans were more abundant than plecopterans in all streams sampled. Fewer species were found, however. Weaver Creek had the richest fauna with 20 taxa followed by Hatchet and East Willow Creek with 19 taxa apiece. Seven families were collected, the majority of individuals belonging to the families Baetidae, and Heptageniidae. The family Baetidae was represented by the genus Baetis. Baetis was one of the most abundant insect groups collected.

An attempt was made to separate the genus into species or species groups but overlap of characters considered prevented 35 this. At least five species were collected. The genus as a whole exists in many lotic habitats. Individual species would have to be determined if Baetis were to have real value as an indicator of stream health. The Ephemerellidae were represented by the greatest number of species and individuals of the ephemeropteran families collected. Fifteen species were collected representing five genera. Drunella spp. (flavilin and/or coloradensis ) and Ephemerella inermis / infrequens (after Hawkins 1982) were the most common groups collected. Early instars of Drunella spp. were very abundant in the March 1985 samples (2 or 3 size classes). Increased larval size at consecutive collection dates suggests rapid larval growth in spring and summer with a late summer/early fall emergence. Larvae were not collected in the November 1984 sample but were abundant in the January 1985 collection. The collection data suggest an egg diapause or early instar period of slow growth.

Ephemerella inermis/infrequens was not collected in the July 1984 samples and was collected in September 1984 samples only at Hatchet Creek. Emergence for these streams is apparently late spring to early summer. Egg diapause or larval aestivation is suggested, apparently temperature dependant.

Of note is the apparent seasonal partitioning of resources within the Ephemerellidae. Serratella tibialis was 36 collected in abundance from Hatchet Creek only in the July 1984 sample. Serratella teresa was collected at Hatchet Creek only on the July 1984 sample date. In the Clear Creek samples, Serratella micheneri was abundant only in July and September, 1984. In Weaver Creek, Ephemerella aurivilli and E. maculata were collected only in the July 1984 sample. S. tibialis was collected from Canyon Creek in July and September, 1984 and S. micheneri only in July. At the East Fork Willow Creek, S.tibialis was collected only in July and September, 1984. Serratella levis and S. micheneri were collected only in the July 1984 sample. The data suggest a long larval stage occurring in cool temperatures for Ε. inermis /infrequens and a short larval stage occurring at warmer temperatures for the other ephemerellids mentioned above. The family Heptageniidae was common in all the streams sampled. Seven genera and nine species were found. Epeorus (Iron) was common in all streams sampled while Rhithrogena was common in all streams except Bidden Creek where it was absent. Ironodes was found in most streams sampled but was common only in samples from Hatchet, Bidden and East Willow Creeks. Edmunds et. al. (1976) report Ironodes habitat as "swiftest mountain streams" equating to near headwater streams here. Epeorus (Iron) sp. 1 (longimanus (?), a heptageniid whose gills form a disc for substrate attachment) occurred primarily in the winter/spring samples. E. (Iron) sp. 2 37

(albertae (?), gills not forming a disc) followed as a summer/fall inhabitant. Collection data suggest a temporal partitioning of resources with obvious morphological adaptations. Another gill disc species, Epeorus (Ironopsis) grandis was collected only from Hatchet, Canyon and East Willow Creeks. E. (Ironopsis) grandis is morphologically similar to E. (Iron) sp.1 and the collections indicate similar seasonal occurrence. They share the same habitat (as clingers) and functional group (scrapers) (Merritt and Cummins 1984). Apparently they share the same niche unless their microhabitat or nutrition source is different. The family Leptophlebiidae was represented by Paraleptophlebia, collected in all streams except Cow Creek but common only in Hatchet and Weaver Creek samples. Isonychia velutina, an oligoneurid, was found at Clear and Weaver Creeks where it was rarely collected. Ameletus, in the family Siphlonuridae, was rare in Hatchet and North Fork Mad River collections but common in collections from East Fork Willow Creek. Collection data from East Fork Willow Creek suggest a summer emergence. Tricorythodes minutes (Tricorythidae) was collected in Little Cow, Clear and Weaver Creeks. A summer/fall emerger (Hubbard and Peters 1978), it was not collected on the April 1984 sampling date, perhaps indicating an early emergence or lateral migration of later instars. 38

TRICHOPTERA () Forty-four taxa representing fifteen families of trichopterans were collected. Greatest richness occurred in Hatchet Creek with 28 taxa followed by Weaver and East Willow Creeks with 20 taxa apiece. The family Rhyacophilidae was represented by eleven species, the most for any trichopteran family collected. All eleven species were found in Hatchet Creek including single specimens of Himalopsyche phryganea and the phytophagous Rhyacophila verrula. Although Rhyacophila spp. show distinguishable characters, keys for the study region are lacking and species were assigned arabic numerals 1 - 9. The hydropsychids were the most abundant family collected, primarily in streams with elevated summer temperatures. Hydropsychids accounted for a third of the insects collected in Little Cow Creek, 43 percent of the total in Clear Creek and 29 percent of the total collected in Weaver Creek. Greatest abundance was reached by Hydropsyche and Cheumatopsyche in the September and November 1984 samples. Some species within these genera display an extreme range of ecological tolerance (Anderson 1976) as suggested by the abundance at elevated summer temperatures. Cheumatopsyche was collected more frequently than Hydropsyche only in Clear Creek (29% to 14%) which had the highest sample date temperatures. Ross (1959) indicates Cheumatopsyche to have the greatest tolerance to elevated water temperatures 39 among the hydropsychid genera. Hydropsyche, and/or Parapsyche were the most common hydropsychids collected at the other study streams. Hydropsyche larvae collected in Hatchet and East Willow Creeks were larger than Hydropsyche larvae found in the other streams (possibly the Morosa group (Alstad 1980). This may be an adaptation of a species or species group to the swift current, coarse detritus and cool temperatures of low order, mountain streams (Wiggens 1977). Arctopsyche and Parapsyche were found in association in Hatchet and East Willow Creeks. Smith (1968) found A. grandis and P. elsis intermixed in the riffles of cool streams in Idaho. Furnish (1979) determined these to be the species found in East Willow Creek, however a positive determination was not made here. Parapsyche was the main hydropsychid collected from Bidden Creek. Larval characters suggest the occurrence of 2 Parapsyche species in Bidden Creek. Parapsyche is characteristic of small, cold, headwater streams (Wiggens 1977). Four genera of the family were collected. Glossosoma was collected in all streams but Bidden Creek. Anagapetus was collected at Bidden, Hatchet and East Willow Creeks. Agapetus was collected only from Hatchet Creek and a single speciman of Protoptila was found in Clear Creek. Wiggens (1977) suggests Agapetus occurs in intermediate sites between the cold water sites frequented by Anagapetus and Glossosoma and the warmer sites where 40

Protoptila occurs. In this study Glossosoma was the dominant glossosomatid genus in the warmer streams and Agapetus was collected only in the coolest. Agapetus was however, collected only in the summer months which is in agreement with the data of Anderson and Bourne (1974) who report an overwintering of eggs and rapid summer larval development of Agapetus bifidus. More than one-third of the Nearctic Trichoptera genera are in the family Limniphilidae (Wiggens 1977), however only five genera were collected in this study. Dicosmoecus and Neophylax, both genera characteristic of streams of varying size (Wiggens 1977), were the only genera collected at more than one site. Apatania was common in Hatchet Creek, Philocasca was collected from Bidden Creek and Ecclisomyia conspersa was collected from East Fork Willow Creek. All three genera characteristically inhabit cool, spring streams. The family Philopotamidae was collected in all streams except Little Cow Creek. Chimarra was collected in Clear and Weaver Creeks, Dolophilodes in Hatchet, Bidden and East Willow Creeks and Wormaldia in all but Bidden Creek. Wiggens and MacKay (1978) suggest Wormaldia to be more characteristic of headwater streams than Dolophilodes, opposite of these results. Four genera of were collected. Brachycentrus was common in Clear and Weaver Creeks. Micrasema was common only in Hatchet but was collected in all 41 streams except Little Cow Creek and North Fork Mad River. aspilus was found only at Clear and Weaver Creeks while Oligoplectrum echo was collected only from Canyon Creek. The Hydroptilidae were collected in the six larger streams, Hydroptila being represented in all six. Stactobiella, occurring primarily in small rapid streams (Anderson 1976), was found only in Little Cow, Clear and Weaver Creeks. Neotrichia was collected only in Weaver Creek and North Fork Mad River. The vast majority of hydroptilids were collected in September 1984, the remainder were collected in July 1984 ( 89% to 11% ). Hydroptilids spend the first four instars as free-living larvae and in most genera the bulk of growth occurs in the final, case building instar (Wiggens 1977). Apparently in the streams sampled fifth instar growth occurs in the summer months. Helicopsyche borealis (Helicopsychidae) and the family Leptoceridae, represented by Oecetis and Mystacides alafimbriata, were collected only in Little Cow, Clear and Weaver Creeks. Both families are known to be prevalent in warmer, lotic waters (Wiggens 1977). H. borealis was extremely abundant in the September and November 1984 Weaver Creek samples. Williams and Hynes (1974) observed a quick succession of generations (May - October) followed by a five or six month egg diapause in an Ontario river. The abundance of larvae in the November sample suggests a late fall 42 emergence or larval diapause (hyperheic ?) through the winter. At least two species of Lepidostoma (Lepidostomatidae) were collected. The genus was common in all streams sampled except Bidden Creek and was collected at each sampling date. Marilia flexuosa, an odontocerid, displayed a seemingly local geographic distribution. It was abundant in Clear Creek, was collected from Little Cow and Hatchet Creeks, but was not collected in any of the other streams. Ross (1956) places Marilia in Ventura and Monteray Counties, California, Wiggens (1977) gives its distribution as Southwest United States and Ontario, Canada, and Anderson (1976) does not list it for Oregon.

A sericostomatid, Gumaga griseola, was common in all streams collected except Canyon and Bidden Creeks. Farula (Uenoidae) was collected only in Bidden Creek where it was common. Farula sp. inhabits small mountain streams (Wiggens 1977).

A single specimen of Heteroplectron californicum () was collected from the North Fork Mad River. Polycentrus sp. (Polycentropidae) was uncommon in Little Cow, Clear and East Willow Creeks.

COLEOPTERA ()

The Coleoptera were represented by nine families, however three of these, Carabiidae, Histeridae and 43

Staphylinidae, are considered semi-aquatic (White et al. 1984). East Willow Creek showed the greatest richness with fifteen taxa, followed by Weaver Creek with thirteen and Clear Creek with eleven. Thirteen taxa representing the family (riffle- beetles) were collected. parvula was collected from each stream, Optioservus and nubifera were collected from each stream except Bidden Creek while Narpus (concolor and/or angustus ) was found in all streams but Hatchet Creek. Optioservus and Z. parvula were the most abundant coleopterans collected, reaching their greatest abundance in the July, September and November 1984 collections. Chapman and Demary (1963) found O. quadrimaculatus adults and elmid larva in general to be reliant on algae, chiefly diatoms. The general summer increase in elmid abundance maybe related to an increase in the algal food source. Ampumixis dispar was collected only in Hatchet and East Willow Creeks. Brown (1972) lists its habitat as rapid, cool mountain streams, suggesting headwater streams. Heterlimnius, also inhabiting rapid mountain streams (Brown 1972), was collected from Hatchet, Weaver and East Willow Creeks and was the only regularly collected elmid in Bidden Creek. Microcylloepus pusillus showed a similar distribution to the caddis- Marilia flexuosa, collected only from Hatchet, Little Cow and Clear Creeks. The second most commonly collected coleopteran group was 44 the family Psephenidae. Psephenus falli and Eubrianax edwardsi were collected frequently in Little Cow, Clear and Weaver Creeks. The family was represented by Acneus sp. in Bidden Creek collections, Acneus quadrimaculatus and E. edwardsi in East Willow Creek and only E.edwardsi in North Fork Mad River. Psephenids were not collected in Hatchet or Canyon Creeks. P. falli was collected in the greatest abundance in the July, September and November 1984 samples suggesting increased numbers with increased temperature and algal food supply. The family Ptilodactylidae was represented by Anchycteis velutina in Bidden Creek and Stenocolus scutellaris in Little Cow and Clear Creeks. A. velutina is an inhabitant of springs while S. scutellaris occurs in streams under 1200 meter elevation entering the Sacramento Valley (Leach and Chandler 1956).

Helichus striatus () was collected from Clear and Weaver Creeks and an undetermined was common in Bidden Creek. The three common beetles (Heterlimnius sp., Anchycteis velutina and Helichus sp.) collected in Bidden Creek displayed no seasonality having been collected in approximately equal numbers at each sampling date. Three genera of were collected from Weaver Creek and two hydrophilid genera were found in East Fork Willow Creek. The taxa determinations made for two Weaver Creek genera are questionable. Enochrus sp., collected 45

November 1984, occurs in a lentic-littoral habitat (White et al. 1984). Hydrobius sp., collected September 1984, is lentic-littoral and an eastern United States genus (White et al. 1984). Tropisternus sp. was also collected in September 1984 from Weaver Creek when flow was at a minimum and mats of dead Cladophora covered the substrate. Ametor scabrosus and Anacaena limbata (?) were collected July 1984 from East Willow Creek. Both belong to genera inhabiting lotic- depositional habitats (White et al. 1984). A single specimen of Oreodytes (Dytiscidae) was collected from Weaver Creek in January 1985. Oreodytes is reported to inhabit fast flowing streams (Leech and Chandler 1956) .

Single specimen of a weevil (Curculionidae) were collected from East Willow Creek in July and November 1984. They were determined to be Lixus however this placement and their aquatic status is questionable.

DIPTERA (True ) The Diptera were the most diverse order collected at all sample sites. More than 123 taxa representing nineteen families were collected. Hatchet and Weaver Creeks displayed the greatest dipteran richness with 64 and 63 taxa collected, respectively.

A majority of the taxa collected (86) were members of the family Chironomidae. Most of the chironomid groups were 46 collected year round suggesting multivoltinism and over wintering as late instar larvae (finder 1986). The subfamily had the highest representation followed by the , and . Within the orthoclads Brillia, Eukiefferiella, Orthocladius, Parametriocnemus, Thienemanniella and Tvetenia occurred in all streams sampled. Cricotopus was common in samples from all streams except Bidden Creek where it was not collected. In the genus Cricotopus the bicinctus, tremelus and trifascia species groups and the subgenus Isocladius were determined. The species of Cricotopus will remain at the generic level in this study. Only Cricotopus (Nostocociadius), a symbiont with the blue-green algae Nostoc parmeloides (Brock 1960), could be diagnosed at the subgenus level for all specimen collected. C. (Nostococladius) was commonly found only in Hatchet Creek. One specimen was collected at Canyon Creek. Eukiefferiella could readily be divided into species groups. Seven species groups were diagnosed. Members of the claripennis and cyanea groups were collected from all streams. Only the brehmi group was collected from less than five streams. Groups of note within the genus Orthocladius are the subgenera O.(Eudactylocladius) and O. (Euorthocladius). Both subgenera were collected at Hatchet Creek only in the January 1985 sample. They accounted for 3.8% and 3.8% ,respectively, 47 of the total sample. Five specimens of O.(Euorthocladius) were collected from East Fork Willow Creek and two specimen were collected from North Fork Mad River in July 1984, the only other collections of either subgenus made in this study. Camptocladius stercorarius, a species reportedly found only in cow dung (Cranston et al. 1983), was found in Bidden Creek. Paraphaenocladius sp. A and B (Saether 1989) were found in Hatchet Creek and apparently represent new species. The Chironominae were well represented by the tribes and Tanytarsini. Within the Chironomini, occurred in all streams sampled. At least two species were collected, mental teeth arrangement being the diagnostic characteristic. The only other Chironomini commonly collected was . The species group rydalensis was collected in each stream except Cow and Bidden Creeks and the North Fork Mad River. The pedellus species group was found only in Clear and Weaver Creeks. A group within the Chironomini of special note was collected only in the September 1984 sample from Weaver Creek. It was diagnosed as near richardsoni by Saether (1989, Personal communication). The genus composed 5.1% of the total sample and most of the specimens were large, apparently late instar larvae.

The Tanytarsini displayed a greater richness than the Chironomini at all streams sampled. Twelve genera were collected. Microspectra, and were 48 collected at each site. Nimbocera was common in Little Cow and Clear Creek samples, rare in Weaver Creek samples and absent in samples from the remaining streams. Nimbocera sp. has been described only from Chile and the Southeast United States (finder and Reiss 1983). The remaining Tanytarsini collected were found infrequently. The genera (?), Lenziella sp., sp. and new type (Saether 1989, personal communication) were collected only from Weaver Creek. Virgatanytarsus had previously been reported only from the Palaearctic and Afrotropical regions (finder and Reiss 1983). The Tanypodinae were represented by nine genera. The subfamily was collected in all streams except Bidden. Pentaneura was the most commonly collected tanypodid being found in six streams, followed by Rheopelopia (5) and Conchapelopia (4). Six genera were found in both Hatchet and Little Cow Creeks. The subfamily was not abundant in the collections and appeared more frequently in the summer than in the winter collections. Brundiniella sp., collected from Hatchet Creek, represents a new type found in California (Saether 1989) . The subfamily Diamesinae was collected in all streams except East Fork Willow Creek. The (gaedii) species group was the diamesid most frequently encountered.

The gaedii group occurred in Little Cow and Clear Creek samples, was common in Weaver Creek and accounted for 8.1% of 49 the total September 1984 North fork Mad River sample. Diamesa was collected in Hatchet, Weaver and Bidden Creeks. A single specimen of Boreoheptagyia was collected at Bidden Creek in July 1984. The specimen does not fit the description given for B. lurida by Saunders (1928). Oliver (1981) does not include California in the distribution for this genus. The family Tipulidae was represented by eleven genera. Antocha monticola and Cryptolabis were collected at each stream except Bidden Creek. Hexatoma was not collected at Canyon or Bidden Creeks and Dicranota was missing only from the Clear Creek samples. Sixteen specimens determined to belong to the Dicranota (Raphidolabina) subgenus were found in the September 1984 Weaver Creek sample. However, Alexander and Byers (1981) list this as a monotypic, Eastern United States subgenus. Hesperocanopa and Limonia were collected only from Hatchet and East Willow Creeks. Pedicia was collected in Bidden Creek and North Fork Mad River. Erioptera was found only in Hatchet Creek, Tipula only in Bidden Creek and Rhabdomastix only in East Willow Creek. With the exception of Tipula, all of the genera collected are placed in the subfamily , a very understudied group (Pritchard 1983). Families collected possessing anatomical structures allowing for stability in swift current include Simuliidae, and Deuterophlebiidae. Simulium was 50 prevalent in all streams collected except Bidden Creek. Prosimulium was collected at all streams except Weaver Creek. Simulium was common in both winter and spring samples. Neither genus displayed a clear seasonal pattern in the samples. Bi- or multi-voltinism (Anderson and Wallace 1984) or the occurrence of more than one species is suggested by the collection data. Blepharicerids were collected from all streams but East Fork Willow Creek and North Fork Mad River. The genus Blepharicera was represented by B. jordani in Little Cow Creek and by B. ostensackeni in Clear, Weaver and Canyon Creeks. An undetermined Blepharicera species was collected from Hatchet and Clear Creeks. Agathon comstockii was collected only from Hatchet Creek while A. doanei was common in Bidden Creek. Single specimens of Philorus and P. californicus were found at Bidden and Hatchet Creeks, respectively. The family Deuterophlebiidae was represented by a lone specimen of the genus Deuterophlebia, collected from Little Cow Creek in April 1984. Specific diagnostic characters for deuterophlebiid larvae are lacking (Kennedy 1960). California records of four deuterophlebiid species have been from elevations above 5000 feet, however specimens have been collected in the general Little Cow Creek region (Kennedy

1958) . Six genera of the family Empidae were collected. 51

Chelifera showed the widest distribution, being collected from each stream, followed by Clinocera, missing only in the Clear Creek, Bidden Creek and North Mad River samples. Questionable determinations include Weidemannia, collected at Canyon Creek but listed as Eastern United States by Teskey (1984), and Oreogeton, a specimen not fitting the description given by Teskey (1984), collected at Little Cow Creek. Other prevalent families include ( variegata), Ceratopogonidae (four genera collected), and Dixidae (two genera apiece). Groups of possible systematic interest include Tanyderidae (Protanyderus, collected in Little Cow and Canyon Creeks), Thaumaleidae (Thaumalea, collected at East Willow Creek) and two undetermined species of Ephydridae collected in the September 1984 Weaver Creek sample.

ODONATA (Dragon and Damselflies) Odonates were regularly collected only in Little Cow and Clear Creeks. Ophiogomphus occidentis (Gomphidae) was collected at each 1984 sampling date in both streams mentioned. It was collected more frequently as flow decreased and temperatures increased. O. specularis was collected only in the November 1983 sample from Clear Creek. Two genera of Libellulidae were collected in Little Cow Creek, Brechmorhoga mendax and Paltothemis lineatipes. B. mendax was common in the September 1984 sample and rare in 52 the November 1984 sample. P. lineatipes occurred in the September sample only. Paulson and Garrison (1977) indicate Calavaras County, California as the northern most record for P. lineatipes . Damselflies (Zygoptera) were represented by two genera in Little Cow Creek. Argia sp. (Caenagrionidae) appeared in the summer samples and a single specimen of Haeterina americans (Calopterygidae) was collected in November 1983. Argia sp. also occurred commonly in the Clear Creek samples of September and November 1984.

LEPIDOPTERA (Butterflies and Moths) The microlepidopteran Petrophila (Pyralidae) was common in the September and November 1984 samples from Little Cow, Clear and Weaver Creeks. Petrophila was not collected at any of the other streams sampled. A lepidopteran larva was collected from East Willow Creek and diagnosed as Cosmopterigidae however its status as an aquatic is questionable.

HEMIPTERA (True bugs) Hemipterans collected were in the families and Gerridae. mormon mormon was collected in Little Cow, Clear and Weaver Creeks primarily in the summer months. Gerrids (water striders) occur on the surface film and were incidentals in the collections. 53

Other orders collected include Megaloptera (Dobsonflies), Orthoptera (Grasshoppers) and Collembola (Springtails). These orders were collected infrequently, the latter two being semi-aquatic at best. 54

Key for table 5. Numbers in parenthesis indicate samples from Bidden, East Willow and/or North Fork Mad. "x" indicates presence in sample.

Table 5. Insect taxa collected (Hatchet Creek). 55

Table 5. Insect taxa collected (Hatchet Creek cont.). 56

Table 5. Insect taxa collected (Hatchet Creek cont.). 57

Table 5. Insect taxa collected (Hatchet Creek cont.). 58

Table 5. Insect taxa collected (Hatchet Creek cont.). 59

Table 5. Insect taxa collected (Hatchet Creek cont.). 60

Table 5. Insect taxa collected (Little Cow Creek). 61

Table 5. Insect taxa collected (Little Cow Creek cont.). 62

Table 5. Insect taxa collected (Little Cow Creek cont.). 63

Table 5. Insect taxa collected (Little Cow Creek cont.). 64

Table 5. Insect taxa collected (Little Cow Creek cont.). 65

Table 5. Insect taxa collected (Clear Creek). 66

Table 5. Insect taxa collected (Clear Creek cont.). 67

Table 5. Insect taxa collected (Clear Creek cont.). 68

Table 5. Insect taxa collected (Clear Creek cont.). 69

Table 5. Insect taxa collected (Clear Creek cont.). 70

Table 5. Insect taxa collected (Weaver Creek). 71

Table 5. Insect taxa collected (weaver Creek cont.) 72

Table 5. Insect taxa collected (Weaver Creek cont). 73

Table 5. Insect taxa collected (Weaver Creek cont.). 74

Table 5. Insect taxa collected (Weaver Creek cont.). 75

Table 5. Insect taxa collected (Weaver Creek cont.). 76

Table 5. Insect taxa collected (Canyon Creek). 77

Table 5. Insect taxa collected (Canyon Creek cont.). 78

Table 5. Insect taxa collected (Canyon Creek cont.). 79

Table 5. Insect taxa collected (Canyon Creek cont.). 80

Table 5. Insect taxa collected (Bidden Creek). 81

Table 5. Insect taxa collected (Bidden Creek cont.). 82

Table 5. Insect taxa collected (Bidden Creek cont.). 83

Table 5. Insect taxa collected (Bidden Creek cont.). 84

Table 5. Insect taxa collected (East Fork Willow Creek). 85

Table 5. Insect taxa collected (East Fork willow Creek cont.). 86

Table 5. Insect taxa collected (East Fork Willow Creek cont.). 87

Table 5. Insect taxa collected (East Fork Willow Creek cont.). 88

Table 5. Insect taxa collected (East Fork Willow Creek cont.). 89

Table 5. Insect taxa collected (North Fork Mad River). 90

Table 5. Insect taxa collected (North Fork Mad River cont.). 91

Table 5. Insect taxa collected (North Fork Mad River cont.). 92

Table 5. Insect taxa collected (North Fork Mad River cont.) 93

Table 5. Insect taxa collected (North Fork Mad River cont.) 94

Figure 3(b). Percentage of ten most abundant taxa. 95

Figure 3(d). Percentage of ten most abundant taxa. 96

Figure 3(f). Percentage of ten most abundant taxa. 97

Figure 3(g). Percentage of ten most abundant taxa. 98

Figure 4(b). Percentage of ten most abundant taxa. 99

Figure 4(d). Percentage of ten most abundant taxa. 100

Figure 4(f). Percentage often most abundant taxa. Figure 4 (g). Percentage of ten most abundant taxa. 1 12

Figure 5(b). Percentage of ten most abundant taxa. 103

Figure 5(d). Percentage of ten most abundant taxa. 104

Figure 5(f). Percentage of ten most abundant taxa. 105

Figure 5(g). Percentage of ten most abundant taxa. 106

Figure 6(b). Percentage of ten most abundant taxa. 10

Figure 6(d). Percentage of ten most abundant taxa. 108

Figure 6(f). Percentage of ten most abundant taxa. 109

Figure 6(g). Percentage of ten most abundant taxa. 110

Figure 7(b). Percentage of ten most abundant taxa. '.11

Figure 7(d). Percentage of ten most abundant taxa. 112

Figure 7(f). Percentage of ten most abundant taxa. 3

Figure 7(g). Percentage of ten most abundant taxa. 114

Figure 8(b). Percentage of ten most abundant taxa. 115

Figure 8 (d). Percentage of ten most abundant taxa. 116

Figure 8(f). Percentage of ten most abundant taxa. 117

Figure 8(g). Percentage of ten most abundant taxa. 118

Figure 9(b). Percentage of ten most abundant taxa. 119

Figure 9(d). Percentage of ten most abundant taxa. 120

Figure 9(f). Percentage of ten most abundant taxa. 121

Figure 9(g). Percentage of ten most abundant taxa. 122

Figure 10(b). Percentage of ten most abundant taxa. 123

Figure 10(d). Percentage of ten most abundant taxa. 124

Figure 10(f). Percentage of ten most abundant taxa. 125

Figure 10(g). Percentage of ten most abundant taxa. DISCUSSION

Species diversity, expressed as a diversity index, has a richness component (number of taxa) and an evenness component (number of individuals per taxa). Cairns (1977) describes a diversity index as a numerical expression that can be used to make comparisons between communities. He feels the diversity index is the best single means of assessing the integrity of freshwater streams. Washington (1984), however, stresses a diversity index reflects community structure and is not a chemical parameter index. Washington states only gross natural water quality changes will be reflected by a diversity index. A correlation was not found between diversity values and individual chemical parameters among the samples taken in this study. Alkalinity, total hardness, and conductivity are all at low levels and would not be expected to have a deleterious affect on the biota (Hynes 1970; Winget and Mangum 1979). pH values measured (6.4 to 8.2) were well within the range of 6.0 to 9.0 which Water Quality Criteria (1968) and Alabaster and Lloyd (1982) found to be non-toxic to aquatic organisms. Turbidity, the presence of suspended solids which reduce the transmission of light, ranged from 2 to 184 T.U. This range had little apparent affect on the benthic diversities of the streams measured (Figure 13(i))-

126 127

Stream slope, when graphically compared with average species diversity for each stream, showed the strongest positive correlation of the parameters measured. Hatchet and Bidden Creeks, with respective slopes of 6 and 29', showed the greatest average species diversities. Stream gradient is important in helping maintain stream substrate quality. An eroding stream section during low stream discharges will normally have a higher percentage of rubble and gravel while a depositing stream section during low stream discharges will have more sands and silts (Winget and Mangum 1979). In general a larger, heterogeneous substrate allows more area for colonization, hence a more diverse invertebrate fauna (Hynes 1970). This relationship, however, did not hold true for all streams measured as indicated by Figure 13(e) in Appendix C. Mean "psi" values were determined for each stream in order to compare substrate composition with mean species diversity indices (Figure 13(f)). Values for substrate composition are similar to stream slope values. Hatchet and Bidden Creeks had the highest percentage of "large" substrate and the highest mean diversity values. As with slope, however, substrate size did not correlate with species diversity values at all streams. Since only riffle habitats (erosional) were sampled, substrate composition at each stream was similar (Figure 2). No significant correlation is suggested by the data. 128

Temperature is an important controlling factor in regulating the distribution and life history patterns of aquatic insects (Hynes 1970; Vannote and Sweeney 1980; Sweeney and Vannote 1986). Although temperatures varied considerably from winter to summer, species diversity index values were not correlated with temperature (Figure 13(h)). Possible explanations for the lack of a correlation include: 1. The confounding effect of high stream velocities associated with low winter temperatures (e.g., hyporeal and lateral migration of benthos). 2. A lack of diel and/or maxima temperature measurements which might influence species diversity. 3. Similar diversity indices values can be obtained for dissimilar communities. A negative correlation between surface water velocity and diversity values is suggested by Figure 13(g). Low diversity values reflect high seasonal rainfall and stream discharge (the primary perturbation in the study area). High stream velocities create difficulty in collecting insects and affect insect movement as mentioned above. The negative correlation most likely illustrates a problem with the sampling method and stream sampling in general, and is probably not a meaningful correlation. In general an association of mayfly, stonefly and caddisfly species in a stream indicates clean water 129 conditions. Reduced numbers of these groups and an increase of species more tolerant to low dissolved oxygen concentrations may indicate the presence of pollution (Chandler 1970; Gaufin 1973). The number of species will not necessarily change but the species community will be greatly changed. If pollution (perturbation) is severe the total number of species will be reduced (Patrick 1977). Chandler (1970) developed a biotic index using a "score" system (Table 1). Based on tolerance to organic pollution, scores were assigned by Chandler to aquatic insect groups. Tolerant groups receive low scores. Scores increase as the pollution tolerance of a taxonomic group decreases. The concept uses the benthic fauna as a monitor of both present stream conditions and those of the recent past. Balloch et al. (1976) give Biotic Score values of 45-300 for moderate pollution levels and scores of over 3000 for unpolluted conditions. Stream biotic index scores compared to physical and chemical parameters measured are presented in Appendix C (Figures 14 (a-i)) . Chandlers Biotic Index is based primarily on tolerance to organic pollution. Streams with high organic pollution levels and low dissolved oxygen concentrations did not occur in this study. In order to establish a biotic index for the Northern California region, Chandlers Biotic Score table should be expanded. Hilsenhoff (1977) successfully applied this concept in evaluating stream conditions in Wisconsin. 130

Tolerance limits of the regional aquatic taxa to physical and chemical stream characteristics could be established and "scores•" assigned. Possibilities include: 1. Inclusion of the and Pteronarcyidae (Plecoptera). The peltoperlids are most commonly collected in cool headwater streams and a high score would be assigned if they were present. The pteronarcids, though occurring in larger, often warmer streams, are sensitive to degraded conditions and would be assigned scores slightly lower than the peltoperlids. 2. Splitting the Chironomidae (Diptera) beyond the family taxonomic level. (The Orthocladius species groups eudactylocladius and euorthocladius were abundant only in the January 1985 sample from Hatchet Creek. The sample site on this sample date was characterized by cold water (1.5 C) of low alkalinity, hardness, conductivity, turbidity and a pH near neutral. A high score would be assigned to these groups). 3. Inclusion of the tipulid (Diptera) genera Cryptolabis and Hesperocanopa as intolerant taxa. Both genera are considered inhabitants of clear, cold, depositional streams (Byers 1984). As taxa intolerant of polluted conditions these genera would be assigned high scores. 131

4. Include the odonate Ophiogomphus occidentis and the lepidopteran Petrophila as taxa tolerant to warm stream conditions and low oxygen tension. Each taxa was abundant at elevated temperatures in Little Cow Creek. If abundant, a middle score would be assigned. Obviously much work would be required to develop environmental tolerance limits for many groups. Such work would be necessary to biologically assess regional stream water quality. As suggested by Cairns (1977), the biological community should be monitored in assessing environmental stress rather than relying solely on the individual organism.

Diversity indices describe community structure but similar values can be found for vastly different communities. The Weaver Creek sample of 9-14-84 has a similar diversity index value as the East Willow Creek sample of 3-31-85 (Figure 11), however, completely different communities are represented. The Weaver Creek sample is dominated by warm water taxa (hydropsychids, Helicopsyche borealis, Hydroptila, Optioservus) while the East Willow Creek sample is dominated by cool water species (primarily ephemeropterans). An approach more informative than the diversity index value is to consider the dominant taxa within a sample. Graphic illustration of the ten most abundant taxa by relative 132

Figure 11. Comparison of samples with similar diversity values but dissimilar community structure. 133 percentage allows for a clearer picture of the community involved (Figures 3 (a) -10 (g)) . The data for the streams considered here suggest two primary community structures within each stream. A "winter" community and a "summer" community. In general the winter community is dominated by insects exhibiting a "cold water" preference and the summer community by insects with a "warm water" preference (Vannote 1973). Little Cow Creek illustrates the varied community structures (Figures 4(a-g)). Winter/spring collections are dominated by Ephemeroptera, Plecoptera, Lepidostoma and Simulium. The summer/fall collections are composed principally of free-living trichopterans, Coleoptera, Diptera, Ophiogomphus and Petrophila. Species components of these groups optimize use of the seasonal habitat. Communities have evolved to take advantage of resources under varying conditions. As a species completes its growth, the species is replaced by species within the same microhabitat, differing principally by the season of growth (Vannote et al. 1980). Major factors influencing life history and the resultant community structure include temperature and nutritional resources (Sweeney 1984). Low winter and high summer temperatures have allowed for the development of dormancy mechanisms at both extremes creating a temporal segregation and decreased competition for a resource (Ward and Stanford 1982). Although temperature is 134 the easier factor to measure and visualize, food resources play an important part in community dynamics. Allochthanous materials provide a winter food base while an autochthanous food base dominates in summer (Vannote et al. 1980). Minshall (1978) feels autotrophic input to streams can be a "viable driving force in the maintenance of community structure." In contrast to Little Cow creek, Hatchet Creek has a more stable annual temperature regime. Temperatures ranged from 1.5' C. to 12' C. at the times benthos were sampled. The resultant collections are dominated primarily by "cold water" forms throughout the year (figures 3(a-g)). "Warm water" forms which occur during summer collections include chironomids and the free-living trichopteran Dolophilodes. Each "warm water" group mentioned is functionally classified as a collector (Merritt and Cummins 1984). Increased phytoplankton growth (Hynes 1970), increased diatom diversity and biomass (Patrick 1970), and flocculation of dissolved organic matter to fine particulate organic matter (Lush and Hynes 1973) occur with increased temperature. Each of these is a nutritional source for collectors. Figures 12(a and b) compare "winter" and "summer" communities for Little Cow and Hatchet Creeks considering dates and temperatures at the times the collections were made. The interaction of temperature and food value as control parameters (Anderson and Cummins 1979) as well as 135

Figure 12(b). Seasonal community structure. 136 other interacting biotic and abiotic factors influence the observed community dynamics. The collection data suggest stream slope to be a major factor determining species composition at the various stream sites. Headwater streams (orders 1-3 (Vannote et al. 1980), considered here to have a slope > 5º) include Hatchet, Bidden and East Fork Willow Creeks. Headwater streams typically exhibit a heterogeneous substrate with a high percentage of boulder and rubble, a relatively narrow temperature range and a high percentage of allochthanous input (see Hawkins 1982). The remaining streams (fourth order except Little Cow (third)) have a lesser gradient, greater annual temperature fluctuation and increased importance of autochthanous input of organic matter. Zonation of stream taxa can be observed when comparing streams of lower order to streams of higher order.

Bidden Creek (second order, 29' slope) is characterized by fauna typical of smaller headwater streams (Table 5). Bidden Creek shares the following taxa with Hatchet Creek (third order, 6 slope) and East Fork Willow Creek (third order, 5' slope): Peltoperlidae; the hydropsychid Parapsyche; Agapetus (Glossosomatidae) and Dolophilodes (Philopotamidae). These streams also displayed the greatest Rhyacophila (Rhyacophilidae) richness and were the only sites where Ironodes (Heptageniidae) was collected frequently. 137

Canyon Creek (fourth order, 2.5' slope) appears to be transitional between the "headwater" and "medium" sized streams considered here. Annual temperature range is relatively low, however the canopy shading effect is lesser than in the "headwater streams". Taxa shared with Hatchet and East Willow Creeks include Epeorus (Ironopsis) grandis (Heptageniidae) and Arctopsyche (). Taxa more typical of larger, warmer reaches include Atherix variegate (Athericidae) and Hesperoperla pacifica (Perlidae) . Little Cow Creek (third order, 2 slope), Clear Creek (fourth order, 2' slope) and Weaver Creek (fourth order, 2' slope) had similar insect communities. Groups collected only in these streams include the naucorid Ambrysus mormon mormon (Hemiptera), Petrophila sp. (Lepidoptera), Argia sp. (Coenagrionidae) and various other odonates. Also represented in these streams were Tricorythodes minutus (Tricorythidae), Helicopsyche borealis (Helicopsychidae), Oecetis (Leptoceridae) and Antocha monticola (Tipulidae), all of which exhibit a warm water preference (Vannote 1973). Of note is the increased abundance of the hydropsychids; Hydropsyche spp. and Cheumatopsyche spp., and the elmid Optioservus spp. in summer/fall collections. Higher water temperatures and increased autochthanous production probably had a significant influence on the increased numbers collected. 138

Four taxa reported only from warmer regions were found in Clear and Little Cow Creeks. These include the odonates Brechmorhoga mendax and Paltothemis lineatipes (Libellulidae) and the trichopteran Marilia flexuosa () (also collected in Hatchet Creek), all reported to have a southwest United States distribution (Merritt and Cummins 1984). P. lineatipes was found as far north as Calavaras Co., California in 1974 (Paulson and Garrison 1977). The fourth taxa is a chironomid larva diagnosed as Nimbocera sp., a genus recorded only from Florida and Chile (Pinder and Reiss 1983). Assuming the taxa determinations to be correct the data suggest a northern dispersal route up the Sacramento valley for these groups reportedly restricted to warmer climates. Perhaps the most interesting sample was collected at Weaver Creek in September 1984. Fourteen taxa were found in this and in no other sample. Of the fourteen, three were Coleoptera larvae and eleven Diptera, six of these in the family Chironomidae. The sample also contained the greatest number of insects of the collections made. The probable reason for this abundance was the alga Cladophora which blanketed the rock substrate. Hynes (1970) indicates certain groups are confined to vegetation covered stones. Hynes also reports Cladophora covered stones show a greater abundance of stream organisms than bare stones. The filamentous algae allow an attachment site, protection (the chironomids formed 139 tubes of the algae) and a nutrition source. Seven of the fourteen taxa determinations are questionable. Either the larvae did not fit diagnostic descriptions or the taxa have not been reported from Northern California. The larvae in question, particularly the dipterans, may undergo rapid growth at high temperatures and a presumed nutritious food supply. Opportunistic rapid development may result in consequent lack of collecting or under collecting by biologists. The North Fork Mad River (fourth order, 1 slope) exhibited similar taxa to the other fourth order streams sampled, however the abundance varied. Large numbers of Optioservus and Hydropsyche and/or Cheumatopsyche appear to be indicative of elevated temperatures and reduced flows for the streams of this study. North Fork Mad River had abundant Optioservus but low numbers of hydropsychids. A large number of chironomids were collected, particularly Polypedilum, Microspectra, Potthastia (gaedii gp.) and Cricotopus, a different assemblage than found in the other streams sampled. The Ephemeroptera, also abundant in the North Mad, were similar to those collected from Hatchet Creek, however, certain groups abundant in Hatchet Creek collections were missing or few in samples from the North Fork of the Mad River. A general faunal zonation occurs among the streams. Many similarities of faunal communities occurred in streams 140 of similar order, slope, temperature and flow regimes. Unexplained variations also occur. The chemical parameters measured in this study did not vary enough from stream to stream to account for the observed differences of benthos. These faunal variations may be attributed to unique physical, chemical and biotic interactions at each stream. Interaction of all components of the habitat ultimately structure the observed community. CONCLUSION

The original intent of this study was to investigate possible correlations between stream insect diversity and physical/chemical stream characteristics. There were no apparent correlations with chemical water properties as measured. The streams sampled showed similar values for selected water chemistry parameters. Values were within tolerance limits for aquatic organisms in general. Taxa intolerant of recorded values would not be expected. Diversity values did not vary with temperature, turbidity, degree slope and substrate composition values as measured. Surface velocity appeared to correlate negatively with diversity values. Possible explanations include the removal of organisms by high flow, downward and lateral migration of the benthos, decreased efficiency of sampling method at high flow and the life history patterns of the insects. In the study region high precipitation coincides with decreased temperatures. A confounding effect may result. In order to measure the effects of stream alkalinity, conductivity, hardness, pH and turbidity on insect diversity major controlling factors should be similar for the streams sampled. Major factors include stream slope, order, velocity, temperature and substrate type. Large variation in controlling factors would tend to mask the probably subtle

141 142 effects of water chemistry (obviously gross variation in water chemistry, i.e. very low pH, would have a major effect on the biota). Graphically viewing the ten most abundant taxa in each sample indicated changes in community structure within a stream both seasonally and among streams. This approach illustrates community dynamics not obvious from diversity index values. Effects of insect life cycle, water temperature and stream slope on community structure become apparent. Biotic indices have been developed to assess "organic enrichment" in streams. Chandlers biotic index was used to investigate its utility in evaluating stream conditions. Though inappropriate for use in the region considered here, development of a regional biotic index could prove valuable in assessing stream conditions. To approach a better understanding of lotic community dynamics further research is needed. Taxonomic and life history research should be stressed. When sampling benthos, terrestrial adults should also be collected for possible adult-larval associations. Time permitting, late instar larvae collected in the field should be reared to maturity for species identification. Ecotypic variation within a genus can reflect different environmental conditions (Hellenthal 1981). Diptera larval in general, the family Chironomidae in particular, should be pursued. Over 143

80 chironomid genera were collected in this study, obviously an important component of the stream ecosystem. Though usually lumped together at the familial systematic level (Chandler 1970, Helliwell 1986) different genera (species) are associated with varied stream habitats (Hynes 1970). Inclusion at the generic or specific level would affect biotic or diversity index values. Knowledge of regional life history patterns is important in evaluating stream communities. A group could be considered missing from a collection due to perturbation when in reality the group was in the egg stage. Obviously a confounding set of data would result. As water resources decline, knowledge of the stream ecosystem will increase in importance. Aquatic insects are an integral part of that system. Continued research leading to positive management plans can help alleviate the stress of greater demand on natural waters. Literature Cited

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Lush, L.L. and H.B.N. Hynes. 1973. The formation of particles in freshwater leacheates of dead leaves. Limnology and Oceanography. 18(6):968-977. Minshall, G.W. 1978. Autotrophy in stream ecosystems. Bioscience. 28:767-771. Minshall, G.W. and J.N. Minshall. 1977. Microdistribution of benthic invertebrates in a Rocky Mountain (U.S.A.) stream. Hydrobiologia. 55:231-249. Naiman, R.J. and J.R. Sedell. 1980. Relationship between metabolic parameters and stream order in Oregon. Canadian Journal of Fisheries and Aquatic Sciences. 37:834-847. Oliver, D.R. 1981. Chironomidae, pp. 423-458. In J.F. McAlpine, B.V. Peterson, G.E. Shewell, H.J. Teskey, J.R. Vockeroth, and D.M. Wood (coords.). Manual of Nearctic Diptera, Vol. 1. Research Branch Agriculture Canada Monograph 27, Ottawa. 674 pp. Patrick,P. 1971. The effects of increasing light and temperature on the structure of diatom communities. Limnology and Oceanography. 16:405-421. Patrick, R. 1977. Identifying integrity through ecosystem study, pp.155-162. In R.F. Ballentine and L.J. Guarraia (eds.). The Integrity of Water. EPA Publications, New York. Paulson, D.R. and R.W. Garrison. 1977. A list and new distributional records of Pacific coast Odonata. The Pan- Pacific Entomologist. 53:147-160. Pielou, E.C. 1969. An Introduction to Mathematical Ecology. John Wiley and Sons, New York. 286 pp. Pinder, L.C.V. 1986. Biology of Freshwater Chironomidae. Annual Review of Entomology. 31:1-23. 150

Pinder, L.C.V. and F. Reiss. 1983. The larvae of the Chironominae (Diptera:Chironomidae) of the Holarctic region-Keys and diagnosis, pp. 293-435. In T. Weiderholm (ed.). Chironomidae of the Holarctic Region. Keys and Diagnosis. Part 1. Larvae. Entomologica Scandinavica Supplement No. 19:1-457. Pritchard, G. 1983. Biology of Tipulidae. Annual Review of Entomology. 28:1-22. Reice, S.R. 1983. Predation and substratum: factors in lotic community structure, pp. 325-345. In T.D. Fontaine and S.M. Bartell (eds.). Dynamics of Lotic Ecosystems. Ann Arbor Science, Michigan. Resh, V.H. 1979. Sampling variability and life history features: basic considerations in the design of aquatic insect studies. Journal of the Fisheries Control Board of Canada. 36:290-311. Ross, Η.Η. 1959. Trichoptera, pp. 1024-1049. In W.T. Edmondson (ed.). Freshwater Biology, John Wiley and Sons, New York. 1248 pp. Saunders, L.G. 1928. The early stages of Diamesa (Psilodiamesa) lurida Garrett (Diptera: Chironomidae). Canadian Entomologist. 60:261-264. Sheldon, A.L. and R.A. Haick. 1981. Habitat selection and association of stream insects: a multivariate analysis. Freshwater Biology. 11(5):395-403. Simpson, E.H. 1949. Measurement of diversity. Nature. 163:688. Smith, S.D. 1968. The Arctopsychinae of Idaho. Pan-Pacific Entomologist. 44(2): Soil-Vegetation Map. 1960a. Blue Lake Quadrangle, N.E., N.W. Quarters, 26 B-2, 26 B-3, Humboldt Co. California. Pacific Southwest Forest and Range Experiment Station, Berkeley, California. 151

Soil-vegetation Map. 1960b. Willow Creek Quadrangle, N.W., S.W. Quarters, 26 A-2, 26 A-3, Trinity Co., California. Pacific Southwest Forest and Range Experiment Station, Berkeley, California. 1965a. Whitmore Quadrangle, N.W. Quarter, 22 C-2, Shasta, Co. California. Pacific Southwest Forest and Range Experiment Station, Berkeley, California. 1965b. Montgomery Creek Quadrangle, S.E. Quarter, 22 B-4, Shasta Co., California. Pacific Southwest Forest and Range Experiment Station, Berkeley, California. 1973,1975. French Gulch Quadrangle, N.E., N.W. Quarters, 24 D-1,24 D-2, Shasta and Trinity Counties and Schell Mountain Quadrangle, S.Ε. Quarter, 24 A-4, Shasta Co., California. Pacific Southwest Forest and Range Experiment Station,. Berkeley, California. 1975. Weaverville Quadrangle, N.W. Quarter, 24 C-2, Trinity Co., California. Pacific Southwest Forest and Range Experiment Station, Berkeley, California. 1980. Hayfork Quadrangle, N.E. Quarter, 25 D-1, Trinity Co., California. Pacific Southwest Forest and Range Experiment Station, Berkeley, California. Sourer, W.L. 1987. Impacts of Suction Dredge Gold Mining on Benthic Invertebrate in Canyon Creek, Trinity County, California. Masters Thesis. Humboldt State University, Arcata, California. 89 pp. Stanford, J.A. and J.V. Ward. 1983. Insect species diversity as a function of environmental variability and disturbance in stream systems, pp. 265-278. In J.R. Barnes and G.W. Minshall (eds.). Stream Ecology. Plenum Press, New York. Surdick, R.F. and A.R. Gaufin. 1978. Environmental Requirements and Pollution Tolerance of Plecoptera. Environmental Monitoring and Support Laboratory, U.S.E.P.A., Cincinnati, Ohio. 417 pp. 152

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Vannote, R.L., G.W. Minshall, K.W. Cummins, J.R. Sedell and C.E. Cushing. 1980. The river continuum concept. Canadian Journal of Fisheries and Aquatic Sciences. 37:130-137. Ward, J.V. and J.A. Stanford. 1982. Thermal response in the evolutionary ecology of aquatic insects. Annual Review of Entomology. 27:97-117. Washington, H.G. 1984. Diversity, biotic, and similarity indices. Water Resources. 18(6):653-694. Water Quality Criteria. 1968. Report of the National Technical Advisory Committee to the Secretary of the Interior. Federal Water Pollution Control Administration, Washington, D.C. 234 pp. White, D.S., W.J. Brigham and J.T. Doyen. 1984. Aquatic Coleoptera, pp. 361-437. In R.W. Merritt and K.W. Cummins (eds.). An Introduction to the Aquatic Insects of North America. Kendall/Hunt, Dubuque, Iowa. 722 pp. Wiggens, G.B. 1977. Larvae of the North American Caddisfly Genera. University of Toronto Press, Toronto, Canada. 401 pp. Wiggens, G.B. and R.J. McKay. 1978. Some relationships between systematics and trophic ecology in Nearctic aquatic insects, with special reference to Trichoptera. Ecology. 59:1211-1220. Wilhm, J.L. 1970. Range of diversity index in benthic macroinvertebrate populations. Journal Water Pollution Control Federation. 42:R221-224. Wilkinson, P. 1986. The Spring Emergence of Plecoptera (Stoneflies) in the Willow Creek Drainage, Humboldt County, California. April-July, 1984. Masters Thesis. Humboldt State University, Arcata, Ca. 100 pp. Williams, D.D. and H.B.N. Hynes. 1974. The occurrence of benthos deep in the substratum of a stream. Freshwater Biology. 4(3):233-256. 154

Winget, R.N. and F.A. Mangum. 1979. Biotic Condition Index:Integrated biological, Physical and chemical stream parameters for management. U.S. Department of Agriculture, Forest Service, Intermountain Region, Ogden, Utah. 51 pp.

Personal Communication:

Saether, Ole A. 1989. University of Bergen, Museum of Zoology. Muséplass 3, N-5007 Bergen, Norway. Appendix A. Taxonomic literature used.

General:

Merritt, R.W. and K.W. Cummins (eds.). 1984. An Introduction to the Aquatic Insects of North America. Kendall/Hunt, Dubuque, Iowa. 722 pp. Usinger, R.L. (ed.). 1956. Aquatic Insects of California. University of California Press, Berkeley, California. 508 pp.

Coleoptera:

Brown, H.Ρ. 1972. Aquatic Dryopoid Beetles (Coleoptera) of the United States. Biota of Freshwater Ecosystems Identification Manual No. 6. Water Pollution Conference Resource Service, E.P.A., Washington, D.C. 82 pp. Brown, H.P. 1983. A Catalog of the Coleoptera of America North of Mexico. Family: Elmidae. United States Department of Agriculture Handbook No. 529-50. Agricultural Research Service. 23 pp. Brown, H.P. and C.M. Murvosh. 1974. A revision of the genus Psephenus (waterpenny beetles) of the U.S. and Canada (Coleoptera, Dryopoidea, Psephenidae). Transactions of the Entomological Society of America. 100:289-340. Hilsenhoff, W.L. 1973. Notes on Dubirapha (Coleoptera: Elmidae) with descriptions of five new species. Annals of the Entomological Society of America. 66:55-61.

Diptera:

Alexander, C.P. 1967. The Craneflies of California. Bulletin of the California Insect Survey No. 8. 269 pp.

155 156

Appendix A. Taxonomic literature used (cont.).

Hogue, C.L. 1973. The Net-winged or Blephariceridae of California. Bulletin of the California Insect Survey No. 15. 82 pp. Hynes, C.D. 1963. Description of the immature stages of Cryptolabis magnistyla Alexander. The Pan-Pacific Entomologist. 36(4):255-260. Knight, A.W. 1964. Description of the tanyderid larva Protanyderus margarita Alexander from Colorado. Bulletin of the Brooklyn Entomological Society. 58:99-102. Mason, W.T. Jr. 1968. An Introduction to the Identification of Chironomid Larvae. Division of Pollution Surveillance, Federal Water Pollution Control Administration, U.S. Department of the Interior, Cincinnati, Ohio. 89 pp. McAlpine, J.F., B.V. Peterson, G.E. Shewell, H.J. Teskey, J.R. Vockeroth and D.M. Wood (coords.). 1981. Manual of Nearctic Diptera. Volume I. Biosystematics Research Institute, Ottawa, Canada. 674 pp. McFadden, M.W. 1967. Soldier Fly Larvae in America North of Mexico. Proceedings of the U.S. National Museum No. 121. 72 pp. Rose, R.H. 1963. Supposed larva of Protanyderus vipio (Osten Sacken) discovered in California. The Pan-Pacific Entomologist. 36(4):273 -274. Saether, Ο.Α. 1980. Glossary of chironomid morphology terminology (Diptera:Chironomidae). Entomologica Scandinavica Supplement No. 14:1-51. Wiederholm, T. (ed.) 1983. Chironomidae of the Holarctic Region. Keys and Diagnoses. Part 1. Larvae. Entomologica Scandinavica Supplement No. 19:1-457. 157

Appendix A. Taxonomic literature used (cont.).

Ephemeroptera:

Allen, R.K. and G.F. Edmunds. 1961. A revision of the genus Ephemerella (Ephemeroptera:Ephemerellidae) II. The subgenus Caudatella. Annals of the Entomological Society of America. 54:603-612. 1961. A revision of the genus Ephemerella (Ephemeroptera:Ephemerellidae) III. The subgenus Attenuatella. Journal of the Kansas Entomological society. 34:161-173. 1962. A revision of the genus Ephemerella (Ephemeroptera:Ephemerellidae) V. The subgenus Drunella in North America. Miscellaneous Publications of the Entomological Society of America. 3:147-179. 1963. A revision of the genus Ephemerella (Ephemeroptera:Ephemerellidae) VI. The subgenus Serratella in North America. Annals of the Entomological Society of America. 56:583-600. 1965. A revision of the genus Ephemerella (Ephemeroptera:Ephemerellidae) VIII. The subgenus Ephemerella in North America. Miscellaneous Publications of the Entomological Society of America. 4:243-282. Edmunds, G.F. and R.K. Allen. 1964. The Rocky Mountain species of Epeorus (Iron ) Eaton (Ephemeroptera:Heptageniidae). Journal of the Kansas Entomological Society. 37:275-288. Edmunds, G.F. Jr., J.L. Jensen and L. Berner. 1976. The Mayflies of North and Central America. University of Minnesota Press, Minneapolis. 330 pp. Morihara, D.K. and W.P. McCafferty. 1979. The Baetis larvae of North America (Ephemeroptera:Baetidae). Transactions of the American Entomological Society. 105:139-221. 158

Appendix A. Taxonomic literature used (cont.).

Needham, J.C., J.R. Traver and Y.Hsu. 1935. The Biology of Mayflies. Comstock Publishing, New York. 759 pp.

Plecoptera:

Baumann, R.H., A.R. Gaufin and R.F. Surdick. 1977. The Stoneflies (Plecoptera) of the Rocky Mountains. Memoirs of the American Entomological Society. 31:1-207. Frison, T.H. 1937. Descriptions of Plecoptera. Bulletin of the Illinois Natural History Survey. 21(3):78-98. Jewitt, S.G.Jr. 1959. The Stoneflies of the Pacific Northwest. Oregon State Monograph Studies in Entomology. Corvalis, Oregon. 3:1-95. Stewart, K.W. and B.P. Stark. 1984. Nymphs of the North American Perlodinae genera (Plecoptera:Perlodidae)• Great Basin Naturalist. 44:373-415. Surdick, R.F. 1985. Nearctic Genera of Chloroperlinae (Plecoptera:Chloroperlidae). University of Illinois Press, Urbana. 146 pp. Szczytko, S.W. and K.W. Stewart. 1979. The genus Isoperla of western North America:holomorphy and systematics, and a new stonefly genus Cascadoperla. Memoirs of the American Entomological Society. 32:1-120.

Trichoptera:

Anderson, N.H. 1976. The Distribution and Biology of the Oregon Trichoptera. Technical Bulletin 134. Agricultural Experiment Station, O.S.U., Corvalis, Oregon. 152 pp. 159

Appendix A. Taxonomic literature used (cont.).

Schuster, G.A. 1984. Hydropsyche ?-Symphitopsyche ?- Ceratopsyche ? : A taxonomic enigma, pp. 339-345. In J.C.Morse (ed.) Proceedings of the Fourth International Symposium on Trichoptera. Dr. W. Junk, Publisher, The Hague. Smith, S.D. 1968. The Rhyacophila of the Salmon River Drainage of Idaho with special reference to larvae. Annals of the Entomological Society of America. 61:655-674. Wiggens, G.B. 1977. Larvae of the North American Caddisfly Genera. University of Toronto Press, Toronto, Canada. 401 pp. Wiggens, G.B., J.S. Weaver and J.D. Unzicker. 1985. Revision of the caddisfly family Uenoidae (Trichoptera). Canadian Entomologist. 117:763-800. Yamamoto, T. and G.B. Wiggens. 1964. A comparative study of the North American species of the caddisfly genus Mystacides (Trichoptera:Leptoceridae). Canadian Journal of Zoology. 42(6):1105-1126. Appendix Β. List of insect taxa collected in eight Northern California streams. Coleoptera Carabiidae spp. Curculionidae Lixus sp. (?) Dryopidae Helichus striatus Dytiscidae Oreodytes sp. Elmidae Ampumixis dispar Cleptelmis spp. C. ornata Dubaraphia sp. (?) Η. Koebelei Lara sp. Microcylloepus pusillus similus Narpus angustus Ν. concolor Optioservus quadrimaculatus Ο. seriatus Rhizelmis nigra Histeridae sp. Hydrophilidae Ametor scabrosus Anacaena limbata (?) Enochrus sp. Hydrobius sp. (?) Tropisternus sp. Psephenidae Acneus quadrimaculatus Eubrianax edwardsi Psephenus haldemani Ptilodactylidae Anchyteis velutina Stenocolus scutellaris Staphylinidae spp. Collembola spp. Diptera Athericidae Atherix variegata Blephariceridae Agathon comstocki A. doanei

160 161

Appendix Β. List of insect taxa collected in eight Northern California streams (cont.).

Diptera (cont.) Blepharicera sp. Β. jordani Β. ostensackeni Dioptosis sp. Philorus californicus Ceratopogonidae Culicoides sp. Dasyhelea sp. Forcipomyia sp. Palpomyia sp. Chironomidae Chironominae sp. Corynocera sp. sp. (?) sp. californicus Lenziella sp. Microtendipes (pedellus gp.) sp. Μ. (rydalensis gp.) sp. Nimbocera sp. Paratanytarsus sp. Polypedilum spp. Pseudochironomus near richardsoni Rheotanytarsus sp. sp. sp. sp. Sublettea sp. Tanytarsus spp. Virgatanytarsus sp. Chironominae sp. 1 Chironominae sp. 2 Diamesinae Boreoheptagyia sp. Diamesa spp. Pagastia sp. Potthastia (gaedii gp.) sp. Sympotthastia sp. (?) Orthocladiinae Brillia sp. Camptocladius stercorarius Corynoneura sp. Cricotopus spp. C. (Cricotopus) (bicinctus gp.) sp. C. (Cricotopus) (nostococIadius gp.) sp. C. (Cricotopus) (tremelus gp.) sp. 162

Appendix Β. List of insect taxa collected in eight Northern California streams (cont.) Diptera (cont.) Cricotopus (Cricotopus) (trifascia gp.) sp. C. (Isocladius) sp. Near Doncricotopus sp. Eukiefferiella (brehmi gp.) sp. Eukiefferiella (claripennis gp.) sp. Ε. (coerulescens gp.) sp. Ε. (cyanea gp.) sp. Ε. (devonica gp.) sp. Ε. (gracei gp.) sp. Ε. (rectangularis gp.) sp. Heterotrisocladius subpilosus Hydrobaenus sp. (?) Krenosmittia sp. Near Krenosmittia sp. Lopescladius sp. Mesocricotopus sp. Nanocladius sp. Orthocladius S. str. sp. Ο. (Eudactylocladius) sp. Ο. (Euorthocladius) sp. Paraphaetocladius sp. Paracricotopus sp. Parakiefferiella sp. Parametriocnemus sp. Paraphaenocladius sp. Paraphaenocladius sp. A Paraphaenocladius sp. Β Paratrichocladius sp. Phaenospectra sp. Pseudorthocladius sp. Rheocricotopus sp. R. fuscipes Stilocladius sp. Symposiocladius lignicola Synorthocladius sp. Thienemanniella sp. Τ. fusca Tokunugaia sp. Tvetenia sp. Tvetenia (paucunca gp.) sp. Orthocladiinae sp. 1 Orthocladiinae sp. 2 Orthocladiinae sp. 3 Tanypodinae Brundiniella sp. Conchapelopia sp. Helopelopia sp. 163

Appendix Β. List of insect taxa collected in eight Northern California streams (cont.) Diptera (cont.) Larsia sp. Nilotanypus sp. Pentaneura sp. Procladius sp. Rheopelopia sp. Zavrelimyia sp. Deuterophlebiidae Deuterophlebia sp. Dixidae Dixa (Dixa) sp. Meringodixa sp. Dolichopodidae Empididae Chelifera sp. Clinocera sp. sp. Hemerodromia Oreogeton sp. Weidemannia sp. (?) Ephydridae sp. 1 Ephydridae sp. 2 Muscidae Limnophora sp. Glutops sp. Psychodidae Maruina sp. Pericoma sp. Sepedon sp. Simuliidae Prosimulium sp. Simulium sp. Euparyphus sp. Tabanidae Sylvius sp. Tabanus sp. Tanyderidae Protanyderus sp. Thaumaleidae Thaumalea sp. Tipulidae Antocha monticola Near Antocha sp. Cryptolabis sp. Dicranota sp. 164

Appendix Β. List of insect taxa collected in eight Northern California streams (cont.).

Diptera (cont.) D. (Rhaphidolabina) sp. Erioptera sp. Hesperocanopa sp. Hexatoma spp. Limonia sp. Pedicia sp. Rhabdomastix sp. Tipula sp. Ephemeroptera Baetidae Baetis spp. Ephemerellidae Attenella delantala Caudatella edmundsi C. heterocaudata heterocaudata C. hystrix Drunella spp. D. doddsi D. pelosa D. spinifera Ephemerella aurivilli (?) Ε. inermis Ε. maculata Serratella levis S. micheneri S. teresa S. tibialis Heptageniidae Cinygma sp. Cinygmula sp. Epeorus (Iron) sp. 1 Ε. (Iron) sp. 2 Ε. (Ironopsis) grandis Heptagenia sp. Ironodes sp. Rhithrogena sp. Leptophlebiidae Paraleptophlebia sp. Oligoneuridae Isonychia velutina Siphlonuridae Ameletus sp. Tricorythidae Tricorythodes minutus 165

Appendix Β. List of insect taxa collected in eight Northern California streams. (cont.).

Hemiptera Gerridae Trepobates sp. Naucoridae Ambrysus mormon mormon Veliidae Microvelia cerifera Lepidoptera Cosmopterygidae Pyroderces sp. Pyralidae Petrophila spp. Megaloptera Corydalidae Neohermes californica Oreohermes crepusculus Odonata Calopterygidae Haeterina americana Coenagrionidae Argia sp. Gomphidae Octogomphus specularis Ophiogomphus occidentalis Libellulidae Brechmorhoga mendax Paltothemis lineatipes Orthoptera Gryllidae sp. Tridactylidae Ellipes minuta Plecoptera Capniidae spp. Chloroperlidae Alloperla sp. Haploperla chilnualna Kathroperla perdita Plumiperla sp. Suwallia sp. Sweltsa sp. Leuctridae spp. Moselia infuscata Nemouridae Malenka sp. Nemoura spiniloba Podmosta sp. Visoka cataractae 166

Appendix Β. List of insect taxa collected in eight Northern California streams. (cont.).

Plecoptera (cont.) Zapada cinctipes Ζ. columbiana Ζ. frigida Ζ. (oregonensis gp.) sp. Peltoperlidae Sierraperla cora Yoraperla brevis Perlidae Calineuria californica Claassenia sabulosa Doroneuria baumanni Hesperoperla pacifica Perlodidae Cascadoperla trictura Chernokrilus sp. Cultus sp. Isoperla spp. Oroperla barbara Osobenus yakimae Perlinodes aurea Rickera sorpta Skwala parallela Pteronarcyidae Pteronarcys californica Ρ. princeps Taeniopterygidae Taenionema sp. Trichoptera Brachycentridae BraChycentrus americanus Micrasema sp. Oligoplectrum echo Calamoceratidae Heteroplectron californicum Glossosmatidae Agapetus sp. Anagapetus sp. Glossosoma sp. Protoptila sp. Helicopsychidae Helicopsyche borealis Hydropsychidae Arctopsyche sp. Cheumatopsyche spp. Hydropsyche spp. Parapsyche spp. 167

Appendix Β. List of insect taxa collected in eight Northern California streams (cont.). Trichoptera (cont.) Hydroptilidae Hydroptila sp. Neotrichia sp. Stactobiella spp. Lepidostomatidae Lepidostoma spp. Leptoceridae Mystacides alafimbriata Oecetis sp. Limnephilidae Apatania sp. Dicosmoecus sp. Ecclisomyia conspersa Neophylax sp. Philocasca sp. Odontoceridae Marilia flexuosa Namamyia plutonis Philopotamidae Chimarra sp. Dolophilodes spp. Wormaldia sp. Polycentropidae Polycentropus sp. Rhyacophilidae Himalopsyche phrygaena Rhacophila verrula Rhyacophila spp. 1-9 Sericostomatidae Gumaga griseola Uenoidae Farula sp. Appendix C. Insect diversity and biotic indices values vs chemical and physical stream parameters.

Figure 13(b). Sample diversity values vs. sample site total hardness values. 168 169

Appendix C. Insect diversity and biotic indices values vs. chemical and physical stream parameters (cont.).

Figure 13(d). Sample diversity values vs. sample site pH values. 170

Appendix C. Insect diversity and biotic indices values vs. chemical and physical stream parameters (cont.).

Figure 13(f). Mean stream sample diversity vs. mean stream substrate composition. 171

Appendix C. Insect diversity and biotic indices values vs. chemical and physical stream parameters (cont.).

Figure 13(h). Sample diversity values vs. sample site temperature values. 172

Appendix C. Insect diversity and biotic indices values vs. chemical and physical stream parameters (cont.).

Figure 13(i). Sample diversity values vs. sample site turbidity values. 173

Appendix C. Insect diversity and biotic indices values vs. chemical and physical stream parameters (cont.).

Figure 14(b). Sample Biotic Score vs. sample site total hardness values. 174

Appendix C. Insect diversity and biotic indices values vs. chemical and physical stream parameters (cont.).

Figure 14(d). Sample Biotic Score vs. sample site pH values. 175

Appendix C. Insect diversity and biotic indices values vs. chemical and physical stream parameters (cont.).

Figure 14(f). Mean stream biotic score vs. mean stream substrate composition. 176

Appendix C. Insect diversity and biotic indices values vs. chemical and physical stream parameters (cont.).

Figure 14(h). Sample Biotic Score vs. sample site temperature values. 177

Appendix C. Insect diversity and biotic indices values vs. chemical and physical stream parameters (cont.).

Figure 14(i). Sample biotic score vs. sample site turbidity values.