The recovery of European freshwater biodiversity has come to a halt

Owing to a long history of anthropogenic pressures, freshwater ecosystems are among the most vulnerable to biodiversity loss. Mitigation measures, including wastewater treatment and hydromorphological restoration, have aimed to improve environmental quality and foster the recovery of freshwater biodiversity. Here, using 1,816 time series of freshwater invertebrate communities collected across 22 European countries between 1968 and 2020, we quantified temporal trends in taxonomic and functional diversity and their responses to environmental pressures and gradients. We observed overall increases in taxon richness (0.73% per year), functional richness (2.4% per year) and abundance (1.17% per year). However, these increases primarily occurred before the 2010s, and have since plateaued. Freshwater communities downstream of dams, urban areas and cropland were less likely to experience recovery. Communities at sites with faster rates of warming had fewer gains in taxon richness, functional richness and abundance. Although biodiversity gains in the 1990s and 2000s probably reflect the effectiveness of water-quality improvements and restoration projects, the decelerating trajectory in the 2010s suggests that the current measures offer diminishing returns. Given new and persistent pressures on freshwater ecosystems, including emerging pollutants, climate change and the spread of invasive species, we call for additional mitigation to revive the recovery of freshwater biodiversity

Species Content and Distribution of the Macrozoobenthos along Rilska River, South-West Bulgaria

Rilska River is one of the left tributaries of Struma River and it is a substantial source of drinking water for the capital city of Sofia. In spite of that the hydrobiological data are quite poor, especially these concerning bottom invertebrate fauna. This study presents the results from research on the macrozoobenthos species composition carried out in 2007-2008 at six sites along the river. During the study period totally 192 benthic taxa were found. The relatively high taxa richness and the presence of species sensitive to pollution at all investigated sites are indicative of stable low-saprobic conditions in the river. It was determined that the species composition along the river continuum differed significantly in the upper and lower part of the river and a tendency of increasing species richness downstream the river was observed