Department of Anthropology, University of Toronto, Toronto, Ontario, Canada.
Department of Anthropology, University of Texas at Austin, Austin, Texas.
Am J Primatol. 2020 Aug;82(8):e23163. doi: 10.1002/ajp.23163. Epub 2020 Jun 30.
For wild primates, demography studies are increasingly recognized as necessary for assessing the viability of vulnerable populations experiencing rapid environmental change. In particular, anthropogenic changes such as habitat loss and fragmentation can cause ecological and behavioral changes in small, isolated populations, which may, over time, alter population density and demographic structure (age/sex classes and group composition) in fragment populations relative to continuous forest populations. We compared our study population of Endangered black howler monkeys (Alouatta pigra) in 34 forest fragments around Palenque National Park (PNP), Mexico (62 groups, 407 individuals), to the adjacent population in PNP, protected primary forest (21 groups, 134 individuals), and to previous research on black howlers in fragments in our study area (18 groups, 115 individuals). We used χ and Mann-Whitney U tests to address the questions: (a) what is the current black howler demographic population structure in unprotected forest fragments around PNP? (b) How does it compare to PNP's stable, continuous population? (c) How has it changed over time? Compared to the PNP population, the fragment populations showed higher density, a significantly lower proportion of multimale groups, and significantly fewer adult males per group. The population's age/sex structure in the fragmented landscape has been stable over the last 17 years, but differed in a higher proportion of multifemale groups, higher density, and higher patch occupancy in the present. In the context of conservation, some of our results may be positive as they indicate possible population growth over time. However, long-term scarcity of adult males in fragments and associated effects on population demographic structure might be cause for concern, in that it may affect gene flow and genetic diversity. The scarcity of adult males might stem from males experiencing increased mortality while dispersing in the fragmented landscape, whereas females might be becoming more philopatric in fragments.
对于野生灵长类动物，人们越来越认识到，对经历快速环境变化的脆弱种群进行人口统计学研究是必要的。特别是，诸如栖息地丧失和破碎化等人为变化会导致小而孤立的种群发生生态和行为变化，这些变化可能会随着时间的推移改变片段种群的种群密度和人口结构（年龄/性别类和群体组成）与连续森林种群相比。我们比较了我们在墨西哥帕伦克国家公园（PNP）周围的 34 个森林片段中濒危黑吼猴（Alouatta pigra）的研究种群（62 个群体，407 个人）与 PNP 中的相邻种群，受保护的原始森林（21 个群体，134 个人），以及我们研究区域内黑吼猴在片段中的先前研究（18 个群体，115 个人）。我们使用 χ 和曼-惠特尼 U 检验来解决以下问题：（a）PNP 周围未受保护的森林片段中黑吼猴的当前人口结构是什么？（b）与 PNP 的稳定、连续种群相比如何？（c）随着时间的推移它发生了怎样的变化？与 PNP 种群相比，片段种群的密度更高，多雄群体的比例明显较低，每个群体的成年雄性数量明显较少。在过去的 17 年中，该种群在破碎景观中的年龄/性别结构一直保持稳定，但在当前情况下，多雌群体的比例更高，密度更高，斑块占有率更高。在保护方面，我们的一些结果可能是积极的，因为它们表明随着时间的推移可能会出现人口增长。然而，在片段中成年雄性长期短缺及其对人口结构的影响可能令人担忧，因为这可能会影响基因流动和遗传多样性。雄性个体的稀缺可能源于雄性个体在破碎的景观中扩散时死亡率增加，而雌性个体在片段中可能变得更加恋地性。
