Effects of water chemistry, land use and climate change on waterbirds in a boreal lake complex

Brownification of freshwater is a global issue with many implications. The high accumulation of organic matter causing the darkening of freshwater is explained by numerous factors including climate and land use. One example of this alteration can be found in the population of waterbirds (fish eaters, diving and dabbling ducks and other species) in lakes Kukkia and Rautajärvi in Finland, where the number of waterbirds has decreased by 40% since the mid-1980s. We run Generalized Linear Mixed Models to determine how climatic, water chemistry and land use factors are interacting with one another and how those interactions impact waterbird density. Our results showed the significance of brownification and climatic factors, as COD (chemical oxygen demand) and turbidity of the water body and wind speed were the most relevant in explaining the decline of waterbirds.