Monday, December 10, 2007 - 9:53 AM

Altitudinal and seasonal zonation of Plecoptera, Trichoptera, and Ephemeroptera along the American Fork River, Utah

Sarah Walker,, Brigham Young University, Department of Biology, 401 WIDB, Provo, UT and C. Riley Nelson,, Brigham Young University, Department of Integrative Biology, WIDB 401, Provo, UT.

Like other insect communities, the riparian corridor demonstrates pronounced altitudinal changes. In the past, the focus of zonation studies has been on aquatic nymphs, so between the years of 2003 and 2005, the adult forms of the orders Plecoptera, Trichoptera, and Ephemeroptera were collected at six sites along the American Fork River from a spring originating on Mount Timpanogos to a site much lower on the valley floor. To compile comprehensive species lists of each site, a variety of sampling methods were employed including malaise traps and lindgren funnels. Abundance and diversity data was tabulated at the sites for each one or two week collecting period to gauge seasonal differences between the sites and to track the dispersal of the adults in the canyon. According to the theory of the mid-domain effect, it was expected that diversity would gradually increase towards the mid-elevation site and then decrease at higher sites. We found that species diversity but not abundance peaks at the mid-elevational site. Diversity and statistical analysis using various indices, with initial emphasis on the Chao-Sorenson index, indicate less similarity between some neighboring sites, rather than a gradual transition of communities. These unique ecotones present interesting community turnover occurences both spatially and temporally. Current field sampling and further data analysis using Multi-dimensional scaling and ANOSIM are being conducted to account for these differences which are thought to be influenced by changes in stream order between sites and human modification of one of the tributary streams.

Species 1: Plecoptera
Species 2: Trichoptera
Species 3: Ephemeroptera