Key environmental drivers structuring stonefly assemblages in the mid-sized streams on the southern slope of the Western Carpathians

Abstract

Rivers and streams possess many characteristics that result from features of their surrounding landscape, e.g. from climate conditions, superficial lithology, soil profile, topography, vegetation cover, and human activities as well. In this study, we determined the impact of superficial geology and catchment land use, as the key landscape drivers affecting the physico-chemical and biological conditions in stream ecosystems, on the structure and values of selected ecological metrics relating to stonefly assemblages. In order to achieve this goal, we sampled 10 mid-sized submountain Carpathian streams flowing through two different geological bedrocks and draining the catchment areas with different dominant land use. As a consequence, these differences, we analyzed together 16 physico-chemical and biological parameters of stream environment. Our results demonstrate that 4 environmental parameter (particulate organic matter, transported inorganic matter, phosphorus and silicon ions), reflecting difference in superficial geology and landuse of the catchment area, played a significant role in the structuring of stonefly assemblages. We also found that catchment land use had an impact on values of the SAS and Saprobic indices as well as on the proportion of Leuctridae/Nemouridae and Brachyptera species in stonefly assemblages. The difference in catchment geology were reflected in values of total species richness and in the proportion of Leuctridae/Nemouridae and Brachyptera species as well.