Wintering bird communities are tracking climate change faster than breeding communities

• Published in: The Journal of animal ecology Vol. 90; no. 5; pp. 1085 - 1095
• Main Authors: Lehikoinen, Aleksi, Lindström, Åke, Santangeli, Andrea, Sirkiä, Päivi M., Brotons, Lluís, Devictor, Vincent, Elts, Jaanus, Foppen, Ruud P. B., Heldbjerg, Henning, Herrando, Sergi, Herremans, Marc, Hudson, Marie‐Anne R., Jiguet, Frédéric, Johnston, Alison, Lorrilliere, Romain, Marjakangas, Emma‐Liina, Michel, Nicole L., Moshøj, Charlotte M., Nellis, Renno, Paquet, Jean‐Yves, Smith, Adam C., Szép, Tibor, Turnhout, Chris
• Format: Journal Article
• Language: English
• Published: England Blackwell Publishing Ltd 01-05-2021; Wiley
• Subjects: Annual variations; Biodiversity and Ecology; Biologi; Biological Sciences; Birds; Breeding seasons; Climate change; Community composition; community ecology; Composition; Ecology; Ekologi; environmental change; Environmental Sciences; global warming; Herbivores; long-term monitoring; Mountains; Natural Sciences; Naturvetenskap; population dynamics; Seasons; Summer; Temperature; Weather; Winter; Zoologi; Zoology; community composition; global warming; long-term monitoring; population dynamics; community ecology; environmental change
• ISSN: 0021-8790; 1365-2656
• DOI: 10.1111/1365-2656.13433

Global climate change is driving species' distributions towards the poles and mountain tops during both non‐breeding and breeding seasons, leading to changes in the composition of natural communities. However, the degree of season differences in climate‐driven community shifts has not been thoroughly investigated at large spatial scales.
We compared the rates of change in the community composition during both winter (non‐breeding season) and summer (breeding) and their relation to temperature changes.
Based on continental‐scale data from Europe and North America, we examined changes in bird community composition using the community temperature index (CTI) approach and compared the changes with observed regional temperature changes during 1980–2016.
CTI increased faster in winter than in summer. This seasonal discrepancy is probably because individuals are less site‐faithful in winter, and can more readily shift their wintering sites in response to weather in comparison to the breeding season. Regional long‐term changes in community composition were positively associated with regional temperature changes during both seasons, but the pattern was only significant during summer due to high annual variability in winter communities. Annual changes in community composition were positively associated with the annual temperature changes during both seasons.
Our results were broadly consistent across continents, suggesting some climate‐driven restructuring in both European and North American avian communities. Because community composition has changed much faster during the winter than during the breeding season, it is important to increase our knowledge about climate‐driven impacts during the less‐studied non‐breeding season.
The authors provide compelling evidence that climate‐driven changes in natural communities are much faster during the less‐studied winter season. They found that regional changes in community composition were linked with regional temperatures both annually and over the long term.