Effects of environmental factors on the distribution and diversity of aquatic oligochaetes

Abstract

The aim of our study was to detect actual distributions of oligochaete species, and to identify their ecological differentiation with respect to environmental factors, altitude, temperature, Oxygen concentration, conductivity, total organic Carbon, and water body type. Although widespread, differentiation of oligochaeta communities in four waterbody types and altitudinal groups can be observed through alpha and beta diversity. Differentiation of oligochaete communities was analysed using MANOVA, while the ecological preferences of species were presented with logistic Gaussian regression analyses. The highest number of oligochaeta species was recorded in oligochaete communities in medium and large rivers. Total beta diversity decreased with decreasing of waterbody size, increasing of substrate size, river flow velocity, as well as altitude. Communities from small mountain rivers and streams and large and medium rivers with larger substrate were separated from other oligochaete communities. When coarser substrate is prevalent in smaller and medium rivers, a domination of a certain family was observed: Lumbriculidae (> 800 m a.s.l.), Propapidae and Enchytraeidae (500-800 m) and Naididae (<500 m a.s.l.). It is clear that common oligochaeta species, with significantly overlapping ranges in running waters in Serbia, still show a clear grouping with respect to preference for certain types of waterbodies.