Freshwater managers and conservationists have long known that aquatic ecosystems are affected by a wide range of human activities, but until recently there has been little evidence-based guidance on how to manage for their impacts. Recent multiple stressor research seeks to untangle how different stressors interact, the impacts they can have, and the management actions that are most effective for tackling specific multiple stressor combinations.
Despite the recent upsurge in multiple stressor studies, there are still significant unanswered questions in the field. One key issue is upscaling results from experiments on aquatic biota based on a small number of stressors to larger – catchment and continental – scales which are useful for shaping management and policy decisions.
A new study providing the first overview of how multiple stressors determine ecological status in European rivers aims to address this shortfall. The study, by Jan U. Lemm from the University of Duisburg-Essen and colleagues from the MARS and SOLUTIONS projects, links the intensity of seven stressors to recently measured ecological status data for more than 50,000 river sub-catchments. Using data from the reporting of Water Framework Directive River Basin Management Plans between 2010-2015, the modelling study area covers almost 80% of Europe’s surface area.
The study, published in the Global Change Biology journal, shows that stressors account for an average of 61% of deviance in ecological status across twelve different river types in Europe. In other words, almost two-thirds of the observed variations in European freshwater biota can be directly attributed to human impacts.
Link to paper: https://onlinelibrary.wiley.com/doi/abs/10.1111/gcb.15504