No abstract

Climate changes have profound effects on the distribution of numerous plant and animal species 1-3 . However, whether and how different taxonomic groups are able to track climate changes at large spatial scales is still unclear. Here, we measure and compare the climatic debt accumulated by bird and butterfly communities at a European scale over two decades (1990)(1991)(1992)(1993)(1994)(1995)(1996)(1997)(1998)(1999)(2000)(2001)(2002)(2003)(2004)(2005)(2006)(2007)(2008). We quantified the yearly change in community composition in response to climate change for 9,490 bird and 2,130 butterfly communities distributed across Europe 4 . We show that changes in community composition are rapid but different between birds and butterflies and equivalent to a 37 and 114 km northward shift in bird and butterfly communities, respectively. We further found that, during the same period, the northward shift in temperature in Europe was even faster, so that the climatic debts of birds and butterflies correspond to a 212 and 135 km lag behind climate. Our results indicate both that birds and butterflies do not keep up with temperature increase and the accumulation of different climatic debts for these groups at national and continental scales.Species are not equally at risk when facing climate change. Several species-specific attributes have been identified as increasing species' vulnerability to climate change, including diets, migratory strategy, main habitat types and ecological specialization [5][6][7] . Moreover, although phenotypic plasticity may enable some species to respond rapidly and effectively to climate change 8,9 , others may suffer from the induced spatial mismatch and temporal mistiming with their resources 10,11 . For instance, species such as great tits and flycatchers have been shown to become desynchronized with their main food supply during the nesting season 12 .However, beyond individual species' fates, climate change should also affect species interactions and the structure of species assemblages within and across different taxonomic groups over large spatial scales [13][14][15] . For instance, ectotherms should be more directly affected by climate warming and taxonomic groups with short generation time should favour faster evolutionary responses to selective pressures induced by climate changes 13 . Yet, whether different taxonomic groups are tracking climate change at the same rate over large areas is still unclear, and methods to routinely assess the mismatch between temperature increases and biodiversity responses at different spatial scales are still missing 16 .Here, we used extensive monitoring data of birds and butterflies distributed across Europe to assess whether, regardless of their species-specific characteristics, organisms belonging to a given group are responding more quickly or more slowly than organisms belonging to another group over large areas. We characterized bird and butterfly communities in 9,490 and 2,130 sample sites respectively by their community temperature index (CTI) for ea...

Rapid reversible changes in organ size as a component of adaptive behaviour Piersma, Theun; Lindstrom, A; Lindström, Åke

db1022.html, respectively. Yearly d 13 C values for individual stations and global annual averages are presented in tables S3 and S4.

Despite an overall advancement in breeding area arrival, one of the latest spring arrivals in northwest Europe since 1950 of several trans-Saharan songbird species occurred in 2011. Year-round tracking of red-backed shrikes and thrush nightingales revealed that the cause of the delay was a prolongation of stopover time during spring migration at the Horn of Africa, which was affected by extreme drought. Our results help to establish a direct link at the individual level between changes in local climate during migration and arrival and breeding condition in Europe thousands of kilometers further north.