Temperature synchronizes temporal variation in laying dates across European hole-nesting passerines

© 2022 The Authors. Ecology published by Wiley Periodicals LLC on behalf of The Ecological Society of America. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

Identifying the environmental drivers of variation in fitness-related traits is a central objective in ecology and evolutionary biology. Temporal fluctuations of these environmental drivers are often synchronized at large spatial scales. Yet, whether synchronous environmental conditions can generate spatial synchrony in fitness-related trait values (i.e., correlated temporal trait fluctuations across populations) is poorly understood. Using data from long-term monitored populations of blue tits (Cyanistes caeruleus, n = 31), great tits (Parus major, n = 35), and pied flycatchers (Ficedula hypoleuca, n = 20) across Europe, we assessed the influence of two local climatic variables (mean temperature and mean precipitation in February–May) on spatial synchrony in three fitness-related traits: laying date, clutch size, and fledgling number. We found a high degree of spatial synchrony in laying date but a lower degree in clutch size and fledgling number for each species. Temperature strongly influenced spatial synchrony in laying date for resident blue tits and great tits but not for migratory pied flycatchers. This is a relevant finding in the context of environmental impacts on populations because spatial synchrony in fitness-related trait values among populations may influence fluctuations in vital rates or population abundances. If environmentally induced spatial synchrony in fitness-related traits increases the spatial synchrony in vital rates or population abundances, this will ultimately increase the risk of extinction for populations and species. Assessing how environmental conditions influence spatiotemporal variation in trait values improves our mechanistic understanding of environmental impacts on populations.

This work was funded by the Research Council of Norway (223257). Malcolm D. Burgess thanks Natural England for its support of the monitoring. Marcel Eens and Rianne Pinxten were funded by the University of Antwerp and FWO Flanders. John Atle Kålås was funded by the Norwegian Environment Agency. Bart Kempenaers was funded by the Max Planck Society. Jesús Martínez-Padilla was funded by ARAID and the Spanish Ministry of Education and Science (PID2019-104835GB-I00). David Canal was supported by the Hungarian Academy of Sciences (MTA Premium Postdoctoral Research Program; ID: 2019-353). Juan Carlos Senar was funded by Project CGL-2020 PID2020-114907GB-C21. Szymon M. Drobniak was funded by the DECRA fellowship (DE180100202). EB was funded by the Ministry of Science and Innovation (Project PID2021-122171NB-I00). The Gotland field work was supported by the Swedish Research Council, the Centre national de la recherche scientifique (CNRS), and the Polish National Science Centre (UMO-2015/18/E/NZ8/00505, UMO-2012/07/D/NZ8/01317). The Pirio and Rouvière field work was funded by the OSU-OREME. The Zvenigorod field work was supported by RSF-FWO (No. 20-44-01005).

Peer reviewed