Original paper

The effects of catchment land-use, near-stream vegetation, and river hydromorphology on benthic macroinvertebrate communities in a south-Swedish catchment

Sandin, Leonard

Abstract

The Emå river catchment in south eastern Sweden has been inventoried for habitat quality (using the Swedish biotope inventory method) along large parts of its course. Benthic macroinvertebrate samples have also been taken at 14 wadable stream sites within the catchment. Here, I quantified the relationship among catchment land-use, near-stream (surrounding area and riparian zone) vegetation, and in-stream hydromorphological variables and also between these variables and benthic macroinvertebrate community composition. Land-use near-stream was the best predictor of variation in the in-stream hydromorphology (explaining 81.4 % of the variation), whereas the catchment land-use explained 22.8 % of the variation in the near-stream zone and 36.7 % of the variation in the in-stream hydromorphology. The benthic macroinvertebrate community composition was most strongly related to the near-stream (surrounding area and riparian zone) vegetation explaining 57.9 % of the lotic macroinvertebrate variation, whereas catchment land-use explained 53.0 % of the variation in the biota, and in-stream habitat features explained 40.0 %. The scale at which a system is observed is important when determining which factor is/are influencing the structure of the ecosystem. The near-stream characteristics were slightly more related in my study to the community composition of the biota than any of the habitat variables were related to (present day) land-use in the catchment. These results imply that the use of a hierarchical organization to manage, assess and predict lotic biotic community process and patterns will enhance both understanding and scientific development in running waters.

Keywords

benthic macroinvertebratescatchment land-usehydromorphologyrunning waterspatial scale