Shifts in fine?scale distribution and breeding success of boreal waterbirds along gradients in ice?out timing and habitat structure

Climate change and other anthropogenic stressors affect freshwater ecosystems worldwide. A prominent manifestation of climate impacts on aquatic systems at high latitudes is the advance ice-out date (IOD). Earlier IOD should be advantageous for species such as migratory waterbirds that are dependent open water to initiate breeding; earlier breeding usually means higher reproductive success. However, may induce phenological mismatches have negative involved. This alter habitat dynamics, challenging selection by individuals. An additional challenge imposed changes in quality, particularly if preferred habitats deteriorate. Here, we investigated how fine-scale distribution individuals success changed along gradients structure (richness emergent vegetation) a boreal waterbird assemblage southeastern Finland from 1991 2018. varied considerably between nearby lakes. The common teal (Anas crecca) horned grebe (Podiceps auritus) shifted toward lakes with relatively late while Eurasian wigeon (Mareca penelope) tufted duck (Aythya fuligula) sparse vegetation. Also, showed decreasing trend early IOD, it increased IOD. Success decreased rich vegetation, opposite was true mallard platyrhynchos) only did not show shift or either environmental gradients. findings suggest potentially positive climate-driven impact phenology (earlier IOD) over-ridden quality. results underline need understand complexity effects multiple their successful management.