Species Composition, Emergence, and Habitat Preferences of Trichoptera of the Sagehen Creek Basin, California, USA
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Great Basin Naturalist Volume 49 Number 2 Article 5 4-30-1989 Species composition, emergence, and habitat preferences of Trichoptera of the Sagehen Creek Basin, California, USA Nancy A. Erman University of California, Berkeley Follow this and additional works at: https://scholarsarchive.byu.edu/gbn Recommended Citation Erman, Nancy A. (1989) "Species composition, emergence, and habitat preferences of Trichoptera of the Sagehen Creek Basin, California, USA," Great Basin Naturalist: Vol. 49 : No. 2 , Article 5. Available at: https://scholarsarchive.byu.edu/gbn/vol49/iss2/5 This Article is brought to you for free and open access by the Western North American Naturalist Publications at BYU ScholarsArchive. It has been accepted for inclusion in Great Basin Naturalist by an authorized editor of BYU ScholarsArchive. For more information, please contact [email protected], [email protected]. SPECIES COMPOSITION, EMERGENCE, AND HABITAT PREFERENCES OF TRICHOPTERA OF THE SAGEHEN CREEK BASIN, CALIFORNIA, USA Nancy A. Erman 1 Abstract. —An extensive study of larvae and adult Trichoptera of the Sagehen Creek basin. Sierra Nevada, California, USA, revealed 77 species representing 14 families and 41 genera. Twenty-six species were restricted to small water bodies (spring sources, seeps, spring streams, temporary ponds, and intermittent streams); 27 were restricted to Sagehen Creek, a second-order stream, and the mouths of two large spring streams. Similarity between species caught at black lights and those in emergence traps was 43%. There were two major peaks in adult emergence by species, midsummer and late summer-fall. A few species emerged during winter or throughout most of the year. The species composition of the community showed affinity with Oregon, the Great Basin, and the Rocky Mountains but very little similarity with the California Coast Range. Four of the most abundant species in the basin have very restricted distributions. Ecological separation of several groups of closely related species could be explained by major differences in larval habitats or by different emergence periods. Trichoptera from the Sierra Nevada of Cali- The primary objectives of the present study fornia have been collected and described in were to determine the species composition, papers over the last several decades, but no emergence periods, and habitat preferences comprehensive studies of species abundance of the Trichoptera community of the Sagehen and distribution exist for the Sierra Nevada or Creek basin. As the study progressed, sec- for any part of it. The Sagehen Creek basin on ondary objectives emerged, such as a com- the east side of the Sierra Nevada has been the parison of collecting methods, development site of a University of California field station of emergence collection techniques for re- and of numerous aquatic biology studies since mote areas, and examination of some taxo- 1951. Trichoptera from this watershed have nomic problems. been critical to several svstematic (i.e., Den- ning Wiggins 1970, 1973, 1977, Parker and Study Area Wiggins 1985) and behavioral studies (Erman 1981, 1984, 1986, 1987). Other aquatic inver- Sagehen Creek basin is on the east side of tebrate work in the Sagehen Creek basin is the northern Sierra Nevada, Nevada and extensive. A comprehensive list of the stone- Sierra counties, California, and on the west- flies was published by Sheldon and Jewett ern edge of the Great Basin in the Lahontan (1967) and updated by R. Baumann, W. Shep- drainage. It includes 2,700 hectares from its ard, B. Stark, and S. Szczytko for the first headwaters (elevation 2,256 m) to its end in North American Plecoptera Conference in Stampede Reservoir (elevation 1,804 m). 1985 (unpublished). Plecoptera material from Mean annual precipitation is 93 cm, most of the Sagehen Creek basin has contributed to which falls as snow. Mean annual temperature many systematic (Jewett 1966, Surdick 1981, at the field station measuring station (1,943 m) Szczytko and Stewart 1979, 1984) and ecologi- is 4.9 C, and temperatures below freezing can cal studies (Sheldon 1969, 1972, 1980). occur in any mouth. Within the Sagehen Creek The Turbellaria have been studied (Kenk basin is a wide diversity of aquatic habitats. 1970, 1972) as has the amphipod genus Stygo- In addition to the second-order, spring-fed bromas (Holsinger 1974); and the Cricotopus- Sagehen Creek, there are many permanent, Nostoc relationship was first described in constant-temperature springs (3.5-9 C) and Sagehen Creek (Brock 1960). The aquatic in- spring streams of various sizes and physical- vertebrate community and secondary produc- chemical conditions, several minerotrophic tion in peatlands have been examined (Erman peatlands (fens) in different stages of evolution and Erman 1975). (Erman 1976, Bartolome et al. in press), a Department of Forestry and Resouree Management. Universitj ol < ialifornia, Berkeley. California 91720 186 April 1989 Erman: California Trichoptera 187 small cirque pond at the head of the basin that solved have been or will be sent to the Royal dries completely about two out of three years, Ontario Museum, Toronto, Canada. and temporary streams that exist each year for varying time periods. Results and Discussion Species Habitats and Distribution Methods A total of 77 species representing 14 families and 41 genera were collected in the Adults were collected with emergence basin (Table 1). Limnephilidae was the most traps, black lights, hand nets, and fish traps. abundantly represented family with 32 spe- Emergence traps were of two types: one, a cies, followed by Rhyacophilidae with 13 spe- 1 X 1-m base pyramidal trap with collecting cies. Larval habitats were determined for bottle (80% alcohol) that was emptied at one- most species and are given in Table 1. Habi- or two-week intervals; the other, a smaller tats could not be determined for 12 species folding trap that could be easily moved to caught only by black light and for whom larvae more remote sites. During the six years of the were unknown. study over 800 one- or two-week emergence Twenty-six species occurred in one small trap samples were collected in 22 locations in water body or a combination of spring the basin, including spring sources, spring sources, spring seeps, spring streams, tempo- streams (first-order streams), an intermittent rary ponds, and intermittent streams but not stream, and Sagehen Creek. Fish traps, used in Sagehen Creek. At least one-third of the in other studies, were closed screen boxes, species in the basin, then, were restricted to open only on the ends. They extended above smaller aquatic habitats. Conversely, at least the water and were emptied from the hinged 27 other species, approximately another one- top (see Erman and Leidy 1975). They were third, were confined to Sagehen Creek and/or useful for collecting both larval and adult cad- near the mouths of the two largest spring disflies. Black lights were used in the vicinity streams only. Twelve species were found in of the U.C. field station. One black light was both general habitat groups, though they may run intermittently in the same location (about have shown a preference for one or the other. 30 m from the nearest water) at the field sta- Fifteen species from six families showed a tion from as early as April to as late as October variety of adaptations for life in variable habi- from 1980 to spring 1987. This light was not a tats at the land-water interface and are dis- trap; specimens were sampled at approxi- cussed in more detail elsewhere (Erman 1981, mately half-hour to one-hour intervals on 111 1986, 1987). Larvae of Clostoeca disjuncta nights. Other portable black lights were used were never found in permanent water. Adults in remote areas. Hand-netting and sweep- of Hesperophylax designatus and Wormaldia netting of vegetation were done at many pachita emerged from an intermittent stream aquatic sites in the basin. just days before it dried completely. Lim- Larvae were collected with kick screens, nephilus peltus left permanent spring streams Surber-type samplers, and scoops. They were and pupated in damp moss; in laboratory rear- also collected by hand-picking. The objective ing studies it could not emerge if left in per- of the combination of sampling techniques manent water. A few species (i.e., Goeracea was to collect, if possible, all Trichoptera spe- oregona, Allomyia cidoipes, Lepidostoma er- cies in the basin and to determine the larval manae) were limited to one or a few springs. habitats of all species collected. To that end, The distribution of the species in springs and many larvae were also reared. Quantitative their requirements will be discussed further sampling was not an objective; however, for in a future paper, the result of a separate study comparative purposes, the emergence traps on Sierra Nevada springs. provided data on relative abundance of spe- Species Abundance cies. A reference collection of most species will Relative abundance of species given in be placed in the California Academy of Sci- Table 1 is based roughly (a) on number of ences, Golden Gate Park, San Francisco. adults caught during the study, (b) on distri- Some of the more rare species and those for bution in numbers of habitats based on emer- which taxonomic questions have yet to be re- gence trapping, and (c) on an assessment of 188 Cheat Basin Naturalist Vol. 49, No. 2 larval abundances. The ratings shown are, of emergence, and attraction to light, affect trap- necessity, somewhat subjective. The 10 spe- ping success and could be considered on a cies designated as abundant were either species-by-species basis. The objective of this caught in very high numbers at black lights study, however, was not to study reasons for and were present as larvae in large numbers in trapping success but to collect all species pos- Sagehen Creek (7 species), or were caught in sible, and no attempt was made to quantify high numbers in emergence traps and in trapping effort for each technique.