INRA, UR35 Comportement et Ecologie de la Faune Sauvage, Institut National de la Recherche Agronomique, B.P. 52627, 31326, Castanet-Tolosan, France.
Centre de Recherche sur la Cognition Animale, Université Paul Sabatier - CNRS, 31062, Toulouse, France.
J Anim Ecol. 2012 Nov;81(6):1327. doi: 10.1111/j.1365-2656.2012.02014.x. Epub 2012 Jul 30.
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.
就地扩散是指在出生地范围和首次繁殖地之间的运动，是种群动态学中最重要的过程之一。个体在扩散和恋地性之间的选择可能取决于条件，受到表型属性和/或环境因素的影响。扩散策略的个体间可变性对种群动态具有深远的影响，特别是对复合种群的维持。因此，更好地理解这种可变性的机制是首要关注的问题。我们研究了 2003 年至 2010 年在法国西南部，60 只幼年期欧洲狍（Capreolus capreolus）的活动范围，这些狍在首次繁殖前用 GPS 项圈进行了为期一年的监测。扩散发生在一个连续的空间范围内，因此将个体分为两类（扩散者与恋地者）可能会导致信息丢失。因此，为了更准确地研究条件依赖型扩散，我们开发了一种基于个体的扩散距离测量方法，该方法考虑了个体间的活动范围变化。我们评估了体重、栖息地异质性程度和性别对扩散起始日期、扩散倾向和距离的影响。总的种群扩散率为 0.34，出生和扩散后家域之间的平均线性距离为 12.3 ± 10.5 公里。扩散距离遵循经典的偏态分布。我们没有发现性别对扩散率或距离的偏差。森林动物的扩散距离小于生活在异质性较大的栖息地的动物。体重较重的个体比体重较轻的个体更有可能、更早和更远地扩散。我们的基于个体的标准化扩散距离与体重呈线性增加，并且有一些迹象表明，在 14 公斤以下的体重阈值下，没有个体扩散。因此，欧洲狍的就地扩散取决于表型属性和环境背景。我们的研究结果表明，种群连通性可能会因平均身体状况的变化而改变，在现代农业景观中典型的丰富和异质栖息地中，这种连通性可能更高。
