Local adaptation of freshwaters to global-driven environmental changes

Background/Question/Methods: Synergies between simultaneous changes in climate warming and runoff of humic substances (brownification) may lead to non-intuitive, detrimental effects on ecosystem function and services of freshwaters. Yet we lack adaptive management to counteract these negative effects and secure the provision of freshwater to a rapidly growing human population. Here we combined data from mesocosm experiments and lake monitoring, and explored management strategies capable of buffering such global-driven environmental impacts on the quality of freshwater resources.

Results/Conclusions: We show experimentally that predicted climatic warming and brownification will interact synergistically to reduce freshwater quality by exacerbating cyanobacterial growth and toxin levels. Furthermore, in a model, based on long term data from a natural system, we demonstrate that local food web management (via fish removal) has the potential to increase the resilience against such changes, and therefore that such local efforts offer an opportunity to secure our freshwater resources under global environmental change. This emphasizes the important role of local-scale policy action to buffer anthropogenic-driven impacts on freshwaters and provide a temporal buffer period until climate mitigation strategies are effectively established.