Climate changes faster than animals adapt

In wildlife, the most commonly observed response to climate change is an alteration in the timing of biological events such as hibernation, reproduction or migration (phenological traits). Changes in body size, body mass or other morphological traits have also been associated with climate change, but -- as confirmed by this study -- show no systematic pattern. The researchers extracted relevant information from the scientific literature to relate changes in climate over the years to possible changes in phenological and morphological traits. Next, they evaluated whether observed trait changes were associated with higher survival or an increased number of offspring. "Our research focused on birds because complete data on other groups were scarce," says lead author Viktoriia Radchuk (Leibniz-IZW). She adds: "We demonstrate that in temperate regions, the rising temperatures are associated with the shift of the timing of biological events to earlier dates."

Co-author Steven Beissinger (Professor at the University of California in Berkeley) says "This suggests that species could stay in their warming habitat, as long as they change fast enough to cope with climate change." However, senior author Alexandre Courtiol (Leibniz-IZW) adds "This is unlikely to be the case because even populations undergoing adaptive change do so at a pace that does not guarantee their persistence." Co-author Thomas Reed (senior lecturer at University College Cork, Ireland) explains "These results were obtained by comparing the observed response to climate change with the one expected if a population would be able to adjust their traits so to track the climate change perfectly."

Even more worrisome is the fact that the data analysed included predominantly common and abundant species such as the great tit (Parus major), the European pied flycatcher (Ficedula hypoleuca) or the common magpie (Pica pica) which are known to cope with climate change relatively well. "Adaptive responses among rare or endangered species remain to be analysed. We fear that the forecasts of population persistence for such species of conservation concern will be even more pessimistic" concludes Stephanie Kramer-Schadt (Head of the Department of Ecological Dynamics, Leibniz-IZW). The scientists hope that their analysis and the assembled datasets will stimulate research on the resilience of animal populations in the face of global change and contribute to a better predictive framework to assist future conservation management actions.