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

Vriend, Stefan J. G. and Grøtan, Vidar and Gamelon, Marlène and Adriaensen, Frank and Ahola, Markus P. and Álvarez, Elena and Bailey, Liam D. and Barba, Emilio and Bouvier, Jean‐Charles and Burgess, Malcolm D. and Bushuev, Andrey and Camacho, Carlos and Canal, David and Charmantier, Anne and Cole, Ella F. and Cusimano, Camillo and Doligez, Blandine F. and Drobniak, Szymon M. and Dubiec, Anna and Eens, Marcel and Eeva, Tapio and Erikstad, Kjell Einar and Ferns, Peter N. and Goodenough, Anne E. and Hartley, Ian R. and Hinsley, Shelley A. and Ivankina, Elena and Juškaitis, Rimvydas and Kempenaers, Bart and Kerimov, Anvar B. and Kålås, John Atle and Lavigne, Claire and Leivits, Agu and Mainwaring, Mark C. and Martínez‐Padilla, Jesús and Matthysen, Erik and van Oers, Kees and Orell, Markku and Pinxten, Rianne and Reiertsen, Tone Kristin and Rytkönen, Seppo and Senar, Juan Carlos and Sheldon, Ben C. and Sorace, Alberto and Török, János and Vatka, Emma and Visser, Marcel E. and Sæther, Bernt‐Erik (2023) Temperature synchronizes temporal variation in laying dates across European hole‐nesting passerines. Ecology, 104 (2): e3908. ISSN 0012-9658

Abstract

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.