Department of Evolutionary Biology and Environmental Studies, University of Zurich, Winterthurerstrasse 190, Zurich, CH-8057, Switzerland.
Kalahari Research Centre, Kuruman River Reserve, Van Zylsrus, 8467, South Africa.
Ecology. 2018 Sep;99(9):1932-1941. doi: 10.1002/ecy.2433. Epub 2018 Jul 27.
Dispersal is a key ecological process that influences the dynamics of spatially and socially structured populations and consists of three stages-emigration, transience, and settlement-and each stage is influenced by different social, individual, and environmental factors. Despite our appreciation of the complexity of the process, we lack a firm empirical understanding of the mechanisms underlying the different stages. Here, using data from 65 GPS-collared dispersing female coalitions of the cooperatively breeding meerkat (Suricata suricatta), we present a comprehensive analysis of the effects of population density, mate availability, dispersing coalition size, and individual factors on each of the three stages of dispersal in a wild population. We expected a positive effect of density on dispersal due to increased kin competition at high densities. We further anticipated positive effects of mate availability, coalition size, and body condition on dispersal success. We observed increasing daily emigration and settlement probabilities at high population densities. In addition, we found that emigration and settlement probabilities also increased at low densities and were lowest at medium densities. Daily emigration and settlement probabilities increased with increasing female coalition size and in the presence of unrelated males. Furthermore, the time individuals spent in the transient stage increased with population density, whereas coalition size and presence of unrelated males decreased dispersal distance. The observed nonlinear relationship between dispersal and population density is likely due to limited benefits of cooperation at low population densities and increased kin competition at high densities. Our study provides empirical validation for the theoretical predictions that population density is an important factor driving the evolution of delayed dispersal and philopatry in cooperative breeders.
扩散是一个关键的生态过程，它影响着具有空间和社会结构的种群的动态，由三个阶段组成——迁出、过渡和定居，每个阶段都受到不同的社会、个体和环境因素的影响。尽管我们意识到这个过程的复杂性，但我们缺乏对不同阶段背后机制的坚实实证理解。在这里，我们利用 65 只佩戴 GPS 的合作繁殖猫鼬（Suricata suricatta）分散雌性联盟的数据，对种群密度、配偶可用性、分散联盟规模和个体因素对野生种群中扩散的三个阶段的影响进行了全面分析。我们预计密度会对扩散产生积极影响，因为高密度下亲缘竞争会加剧。我们还预计，配偶可用性、联盟规模和身体状况会对扩散成功产生积极影响。我们观察到，在高种群密度下，每日迁移和定居的概率会增加。此外，我们发现，在低密度下，迁移和定居的概率也会增加，而在中密度下，迁移和定居的概率最低。每日迁移和定居的概率随着雌性联盟规模的增加和无亲缘雄性的存在而增加。此外，个体在过渡阶段花费的时间随着种群密度的增加而增加，而联盟规模和无亲缘雄性的存在则会减少扩散距离。观察到的扩散与种群密度之间的非线性关系可能是由于低种群密度下合作的有限收益以及高密度下亲缘竞争的增加所致。我们的研究为理论预测提供了实证验证，即种群密度是推动合作繁殖者延迟扩散和恋地性进化的重要因素。
