Roadmap for identifying priority areas to monitor the effects of climate change on European rivers

There is an urgent need for planning actions to mitigate biodiversity loss worldwide, which involves developing assessment methods to help decision-makers identifying areas most at risk and prioritizing action.  This requires robust data and analyses but it also implies thinking about realistic and cost-effective measures. Fresh waters host an important part of global biodiversity but freshwater organisms are expected to be profoundly impacted by the predicted increase in water temperatures and discharge alterations associated with climate change. However, available models focus mostly on changes in air temperature, potentially failing to incorporate these impacts. Given that freshwater biodiversity is declining at an alarming and exponentially increasing rate, there is an urgent need to monitor the potential effects of climate change. Here, we modeled the distribution of freshwater macroinvertebrates across Europe for present and future conditions including recently available data on water temperature and discharge. We also included other environmental variables that might be relevant in understanding the current spatial distribution of invertebrates (e.g. geology, adjacent land use). We used 40 datasets of standardized monitoring protocols of freshwater invertebrates spanning 23 years. Then a score of the vulnerability to climate change was attributed to each taxon based on the models. Finally, the average community indicator calculated for all European rivers allowed us to identify relevant regions for monitoring climate change using a planning conservation tool.