eLTER led long-term study shows that recovery of European freshwater biodiversity has stalled since the 2010s

In their paper 'The recovery of European freshwater biodiversity has come to a halt', eLTER researchers, in collaboration with a large international team, examine the state and development of invertebrate biodiversity in European rivers. In their study, published in the renowned journal 'Nature', the authors show that biodiversity in river systems from 22 European countries has increased significantly over a period from 1968 to 2020. However, these increases occurred mainly prior to 2010 and, unfortunately, biodiversity has remained at more or less constant levels since then. While the increases in biodiversity in the 1990s and 2000s likely reflect the effectiveness of water quality improvements and restoration projects, the stagnant trend that followed suggests that past actions have been exhausted. The authors warn that the stagnated trends indicate that many river systems have not been able to fully regenerate. Therefore, they call for additional measures to revive the recovery of biodiversity in inland waters – freshwater ecosystems that are and continue to be exposed to serious pressures such as pollution, invasive species, and climate change.

Starting from > 150 riverine invertebrate time series from 59 eLTER sites across 9 European countries, eLTER scientists reached out to the wider freshwater biodiversity community in Europe by launching a data call in 2020. This resulted in a comprehensive dataset of 1,816 time series, comprising 714,698 individuals of 2,648 taxa from 26,668 samples. The analyses show significant increases in biodiversity over the 53-year period. The number of unique taxa increased 0.73 percent per year, the number of groups of taxa performing different ecological roles increased 2.4 percent per year, and total abundance of invertebrates increased 1.17 percent per year.