Benthic Macroinvertebrates in Arroyo Seco River

(Taken from abstract online.) In the Arroyo Seco watershed, located east of Big Sur in Central California, a study was conducted to assess changes in the environment and their related changes in benthic macro-invertebrate diversities. By comparing differences in substrate to the corresponding diversity levels of insect communities, a relationship between substrate and biological metrics can be formed. To better understand this relationship, macro-invertebrate abundance levels, taxa richness, EPT taxa (number of taxa found in the orders: Ephemeroptera (mayflies), Plecoptera (stoneflies), and Trichoptera (caddis flies)), EPT taxa composition and dominant taxa composition were analyzed given a cobble versus sand dominated substrate. EPT taxa, EPT composition, and taxa richness measures were higher in the upper site and decreased in the lower site. Dominant taxa composition was found to be higher in the sandy substrate than the cobble substrate. Overall, less diversity was found in the sandy substrate (lower site) than in cobble substrate (upper site).