Author/Editor		Boggero, A; Fuereder, L; Lencioni, V; Simčič, T; Thaler, B; Ferrarese, U; Lotter, A F; Ettinger, R
Title		Littoral chironomid communities of Alpine lakes in relation to environmental factors
Type		članek
Source		Hydrobiologia
Vol. and No.		Letnik 562
Publication year		2006
Volume		str. 145-65
Language		eng
Abstract		The results of a study of littoral chironomid communities from 89 lakes in the Alps are presented. The lakes are located on the northern and southern sides of the Alps from the western Bernese to the eastern Julian Alps. Due to the different origins of the data set here considered, different sampling years and sampling methodologies were adopted.All of the lakes were sampled during the ice-free season, but 79/89 lakes were sampled mainly in autumn 2000, while for a few of them the sample dated back to 1996 or the early 90s. Samples were taken by kicking the different substrata or a stretch of lakeshore (10-30m) for at least 2-5 min with a standard net and were then preserved in alcohol. Larvae and pupal exuviae were sampled by skimming the lake surface with the same net, to extend identification to species level. Notwithstanding the large altitudinal gradient, almost all of the lakes are situated above the timberline, and show a wide range of morphological (depth, watershed and lake area) and chemical characteristics. Chironomids were the most abdundant insects represented in these lakes, with highest abundances at pHbetween 6.0 and 7.5. In particular, Orthocladiinae and Chironominae were the two subfanilies with the widest distribution. Altitude and temperature played an important role in determining their distribution, the higher altitudes were dominated by the former, whereas the latter were more numerous in lower lakes. The prevalence of Orthocladiinae and tanytarsini at high altitudes was regarded as a general pattern of taxonomic composition in harsh climatic areas. A reverse condition occurred only in the Julian Alps, where Tanytarsini dominate, followed by tanypodinae and rare Orthocladiinae. (Abstract trunacted at 2000 characters)
Descriptors		FRESH WATER ECOSYSTEM WATER POLLUTANTS CHIRONOMIDAE POPULATION DENSITY SWITZERLAND AUSTRIA ITALY SLOVENIA