Gaillard J-M, Hewison A J M, Kjellander P, Pettorelli N, Bonenfant C, Van Moorter B, Liberg O, Andren H, Van Laere G, Klein F, Angibault J-M, Coulon A, Vanpé C
UMR 5558 Biométrie et Biologie Evolutive, Bâtiment 711, UCB Lyon 1, 43 boulevard du 11 novembre 1918, 69622 Villeurbanne Cedex, France.
Proc Biol Sci. 2008 Sep 7;275(1646):2025-30. doi: 10.1098/rspb.2008.0393.
It is commonly assumed that the propensity to disperse and the dispersal distance of mammals should increase with increasing density and be greater among males than among females. However, most empirical evidence, especially on large mammals, has focused on highly polygynous and dimorphic species displaying female-defence mating tactics. We tested these predictions on roe deer, a weakly polygynous species of large herbivore exhibiting a resource-defence mating tactic at a fine spatial scale. Using three long-term studies of populations that were subject to the experimental manipulation of size, we did not find any support for either prediction, whether in terms of dispersal probability or dispersal distance. Our findings of similar dispersal patterns in both sexes of roe deer suggest that the underlying cause of natal dispersal is not related to inbreeding avoidance in this species. The absence of positive density dependence in fine-scale dispersal behaviour suggests that roe deer natal dispersal is a pre-saturation process that is shaped by heterogeneities in habitat quality rather than by density per se.
人们通常认为，哺乳动物的扩散倾向和扩散距离应随着密度的增加而增加，且雄性的扩散倾向和距离应大于雌性。然而，大多数实证证据，尤其是关于大型哺乳动物的证据，都集中在表现出雌性防御交配策略的高度多配偶和两性异形物种上。我们以狍子为对象对这些预测进行了测试，狍子是一种轻度多配偶的大型食草动物，在精细的空间尺度上表现出资源防御交配策略。通过对三个经过大小实验操纵的种群进行长期研究，我们没有发现任何证据支持这两个预测，无论是在扩散概率还是扩散距离方面。我们关于狍子两性扩散模式相似的研究结果表明，该物种出生扩散的根本原因与避免近亲繁殖无关。在精细尺度的扩散行为中缺乏正密度依赖性，这表明狍子的出生扩散是一个预饱和过程，它是由栖息地质量的异质性而非密度本身塑造的。
