Land use is considered one of the main stressors on biodiversity patterns of freshwater ecosystems, with up to 80% non-natural regional land cover in Europe. Consequently human impacts on freshwater biodiversity are numerous and wide-ranging. Here, we address the impact of arable and urban landscapes, on the diversity of 11 organism groups encompassing vertebrates, invertebrates and plants, occurring in five freshwater ecosystems: rivers, floodplains, lakes, ponds and groundwater. In addition, nine geo-climatic variables (e.g. latitude, longitude, precipitation) were used to quantify the independent, overlapping and interacting effects of land use and natural descriptor variables. Biodiversity response was computed as taxon richness, Shannon diversity, taxon rareness and taxonomic distinctness.
The four biodiversity metrics were analysed using a variation partitioning scheme based on boosted regression trees (BRT) and subsequently with generalised linear modelling (GLM). The analyses sought: i) to partition the unique, shared and unexplained variation in the metrics explained by both groups of descriptor variables and ii) to quantify the contribution of each descriptor variable to biodiversity variation in the data.