Atle Mysterud, Max Kröschel, Nicolas Morellet, Ferdinando Urbano, Robin Sandfort, Johannes De Groeve, Peter Sunde, Leif Sönnichsen, Anders Jarnemo, Mark Hebblewhite, Daniel R. Eacker, John D. C. Linnell, Luca Pedrotti, Benedikt Gehr, Horst Reinecke, Marco Heurich, A. J. Mark Hewison, Stefano Focardi, Petter Kjellander, Francesca Cagnacci, Wibke Peters, Bavarian State Institute of Forestry, University of Montana, University of Oslo (UiO), Unité de recherche Comportement et Ecologie de la Faune Sauvage (CEFS), Institut National de la Recherche Agronomique (INRA), Norwegian Institute for Nature Research (NINA), Consiglio Nazionale delle Ricerche (CNR), Universiteit Gent = Ghent University [Belgium] (UGENT), Fondazione Edmund Mach - Edmund Mach Foundation [Italie] (FEM), Centre d’Ecologie Fonctionnelle et Evolutive (CEFE), Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-École pratique des hautes études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre international d'études supérieures en sciences agronomiques (Montpellier SupAgro)-Institut National de la Recherche Agronomique (INRA)-Université Paul-Valéry - Montpellier 3 (UPVM)-Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro), Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut de Recherche pour le Développement (IRD [France-Sud]), Department of Evolutionary Biology and Environmental Studies, University of Zurich, Department of Conservation and Research, Bavarian Forest National Park, Halmstad University, Grimsö Wildlife Research Station, Department of Ecology, Swedish University of Agricultural Sciences (SLU)-Swedish University of Agricultural Sciences (SLU), University of Freiburg [Freiburg], Forest Research Institute Baden-Württemberg - Forstliche Versuchs- und Forschungsanstalt Baden-Württemberg, Parco Nazionale dello Stelvio, Partenaires INRAE, Georg-August-University [Göttingen], Universität für Bodenkultur Wien [Vienne, Autriche] (BOKU), Leibniz Institute for Zoo and Wildlife Research (IZW), Leibniz Association, Polish Academy of Sciences (PAN), Aarhus University [Aarhus], Harvard University [Cambridge], Vectronic Aerospace GmbH, Autonomous Province of Trento (BECOCERWI) [3479], EU-programme INTERREG IV (EFRE Ziel 3), 'Marie Claire Cronstedts Stiftelse' foundation, Swedish Environmental Protection Agency, Swedish Association for Hunting and Wildlife Management, Region Skane, Stiftelsen Skanska Landskap, Hogestads and Christinehofs Fideikommiss, Ittur Jakt AB, Vira Bruk AB, Holmen Skog AB, Sveaskog, Karl-Erik Onnesjos stiftelse for vetenskaplig forskning och utveckling, Stiftelsen Oscar och Lili Lamms mine, Ericsbergs Fideikommis AB, Agerup and Elsagardens Sateri AB, Kolmardens insamlingsstiftelse/Taby Allmanning, Norwegian Environment Agency, Research Council of Norway [212919, 251112], Buskerud county, Centre for Advanced Study Oslo, Norway, Institute for Zoo and Wildlife Research (IZW), Mammal Research Institute - Polish Academy of Sciences, Polish Ministry of Science and Higher Education [N N304172536], and NASA [NNX11AO47G]
The most common framework under which ungulate migration is studied predicts that it is driven by spatio–temporal variation in plant phenology, yet other hypotheses may explain differences within and between species. To disentangle more complex patterns than those based on single species/ single populations, we quantified migration vari-ability using two sympatric ungulate species differing in their foraging strategy, mating system and physiological constraints due to body size. We related observed variation to a set of hypotheses. We used GPS-collar data from 537 individuals in 10 roe Capreolus capreolus and 12 red deer Cervus elaphus populations spanning environmental gra-dients across Europe to assess variation in migration propensity, distance and tim-ing. Using time-to-event models, we explored how the probability of migration varied in relation to sex, landscape (e.g. topography, forest cover) and temporally-varying environmental factors (e.g. plant green-up, snow cover). Migration propensity varied across study areas. Red deer were, on average, three times more migratory than roe deer (56% versus 18%). This relationship was mainly driven by red deer males which were twice as migratory as females (82% versus 38%). The probability of roe deer migration was similar between sexes. Roe deer (both sexes) migrated earliest in spring. While territorial male roe deer migrated last in autumn, male and female red deer migrated around the same time in autumn, likely due to their polygynous mating system. Plant productivity determined the onset of spring migration in both species, but if plant productivity on winter ranges was sufficiently high, roe deer were less likely to leave. In autumn, migration coincided with reduced plant productivity for both species. This relationship was stronger for red deer. Our results confirm that ungulate migration is influenced by plant phenology, but in a novel way, that these effects appear to be modulated by species-specific traits, especially mating strategies.