Lake quality affects waterfowl migratory routes: A joint CanMove project

In a cooperative CanMove project we used long-term databases on fluctuations in regional bird abundances as well as on limnological monitoring to study interactions between migrating waterfowl and stop-over lake ecosystems quality. We show that despite the large amount of migratory waterfowl, our study site L. Krankesjön, was not negatively affected by the waterfowl which removed less than 3% of the macrophyte biomass per year. Moreover, we show that most waterfowl species occured in lower abundances during periods with low density of macrophytes, than when submersed macrophytes flourished and the water was clear. This pattern was not affected by regional fluctuations in abundances. Hence, our study suggest that some migratory waterfowl taxa select stop-over lakes based on stop-over habitat quality, suggesting that migratory routes are not fixed but instead adjusted over time. If you are interested in reading the whole paper go to: http://www.limnol.lu.se/limnologen/publikationer/834.pdf