COS 92-5
Birds distributions change, but not always in response to climate
Despite an increasing number of studies focusing on the impacts of climate change, large knowledge gaps remain about which species are able to track temperature changes. In this study we utilise a long-term dataset to model distribution changes of 99 common Swedish breeding bird species, whilst accounting for potential sampling bias. We examine 1) whether shifts have occurred in geographic and climatic niche space, and 2) whether these shifts have been consistent in time, using two complementary methods based on direct abundance measurements and model fitting.
Results/Conclusions
We find that i) more than a third of the species considered have significantly shifted their spatial distribution; ii) several species that have shifted have done so in the direction and amplitude expected by niche tracking; iii) most detected shifts cannot be attributed to climate tracking, but rather to other ecological processes. Our results confirm recent studies conducted at the European scale with entire communities, and show clearly the interest of combining temperature and geographic gradients in the study of species’ response to climate change. Our results particularly highlight the risk of using only latitude as a proxy for climate driven range-shifts, as latitude can reflect many other mechanisms than climate.