Channel stability and the structure of coastal stream aquatic insect assemblages
Markos, Peter D.; Kaller, Michael D.; Kelso, William E.
published: Aug 1, 2016
published online: Jun 23, 2016
manuscript accepted: Jun 10, 2016
manuscript received: Oct 13, 2015
ArtNo. ESP141018803001, Price: 29.00 €
Abstract Human population growth in coastal areas will be accompanied by increasing stress on the low-gradient, fine-substrate streams that often characterize lowland watersheds. Although assessment of anthropogenic influences on these streams is of increasing importance, research on habitat-biota relationships in coastal plain streams has lagged behind research efforts in upland systems. In particular, channel stability and its relationships with stream biota has received little attention, although anthropogenic influences on channel stability from land use changes are well-documented in other systems. We assessed the influence of channel stability and physicochemical stream characteristics on the density, diversity, evenness, and % Ephemeroptera, Plecoptera, and Trichoptera (EPT) of aquatic insect assemblages in sand-substrate coastal plain streams in the Gulf of Mexico, southeastern USA. Of 26 stream habitat and water quality characteristics, 23 were associated with the integrated metric of the Pfankuch stability index (PSI). Additionally, the PSI was significantly related to insect density, diversity, evenness, and % EPT. The PSI was also related to densities of the 17 most abundant insect taxa, including the mayfly Stenonema and adult and larval elmid beetles Ancyronyx and Stenelmis, which occurred at higher abundances in less stable streams, and Hydropsyche caddisfly larvae, which were more abundant in more stable streams. Despite the instability of sand-substrate coastal plain stream channels, the PSI distinguished among study streams. We suggest this index as appropriate for use as a physical habitat and biological assessment tool in lowland coastal streams.