title: Condition-dependent natal dispersal in a large herbivore: heavier animals show a greater propensity to disperse and travel further.
abstract: Natal dispersal is defined as the movement between the natal range and the site of first breeding and is one of the most important processes in population dynamics. The choice an individual makes between dispersal and philopatry may be condition dependent, influenced by either phenotypic attributes and/or environmental factors. Interindividual variability in dispersal tactics has profound consequences for population dynamics, particularly with respect to metapopulation maintenance. A better understanding of the mechanisms underlying this variability is thus of primary interest. We investigated the ranging behaviour of 60 juvenile European roe deer, Capreolus capreolus, monitored with GPS collars for 1 year prior to their first reproduction, from 2003 to 2010 in South-West France. Dispersal occurs across a spatial continuum so that dividing individuals into two categories (dispersers vs. philopatric) may lead to information loss. Therefore, to investigate condition-dependent dispersal more accurately, we developed an individual-based measure of dispersal distance, which took into account interindividual variation in ranging behaviour. We assessed the influence of body mass, the degree of habitat heterogeneity and sex on dispersal initiation date, dispersal propensity and distance. The overall population dispersal rate was 0·34, with a mean ± SD linear distance between natal and post-dispersal home ranges of 12·3 ± 10·5 km. Dispersal distances followed a classical leptokurtic distribution. We found no sex bias in either dispersal rate or distance. Forest animals dispersed less than those living in more heterogeneous habitats. Heavier individuals dispersed with a higher probability, earlier and further than lighter individuals. Our individual-based standardised dispersal distance increased linearly with body mass, with some suggestion of a body mass threshold of 14 kg under which no individual dispersed. Natal dispersal in roe deer was thus dependent on both phenotypic attributes and environmental context. Our results suggest that population connectivity can be altered by a change in average body condition and is likely higher in the rich and heterogeneous habitats typical of modern day agricultural landscapes.
authors: INRA, UR35 Comportement et Ecologie de la Faune Sauvage, Institut National de la Recherche Agronomique, B.P. 52627, 31326, Castanet-Tolosan, France.
authors: Lucie
authors: L
authors: Debeffe
authors: INRA, UR35 Comportement et Ecologie de la Faune Sauvage, Institut National de la Recherche Agronomique, B.P. 52627, 31326, Castanet-Tolosan, France.
authors: Nicolas
authors: N
authors: Morellet
authors: INRA, UR35 Comportement et Ecologie de la Faune Sauvage, Institut National de la Recherche Agronomique, B.P. 52627, 31326, Castanet-Tolosan, France.
authors: Bruno
authors: B
authors: Cargnelutti
authors: INRA, UR35 Comportement et Ecologie de la Faune Sauvage, Institut National de la Recherche Agronomique, B.P. 52627, 31326, Castanet-Tolosan, France.
authors: Bruno
authors: B
authors: Lourtet
authors: Centre de Recherche sur la Cognition Animale, Université Paul Sabatier - CNRS, 31062, Toulouse, France.
authors: Richard
authors: R
authors: Bon
authors: Laboratoire "Biométrie et Biologie Évolutive", Unité Mixte de Recherche 5558, Université de Lyon, Université de Claude Bernard Lyon 1, 43 boulevard du 11 novembre 1918, FR 69622, Villeurbanne Cedex, France.
authors: Jean-Michel
authors: JM
authors: Gaillard
authors: INRA, UR35 Comportement et Ecologie de la Faune Sauvage, Institut National de la Recherche Agronomique, B.P. 52627, 31326, Castanet-Tolosan, France.
authors: A J
authors: AJ
authors: Mark Hewison
mesh_terms: D063147:Animal Distribution; D000818:Animals; D001835:Body Weight; D003670:Deer / Q000502:physiology*; D004777:Environment; D005260:Female; D005602:France; D040362:Geographic Information Systems; D008297:Male; D011157:Population Dynamics; D012621:Seasons; D012737:Sex Factors