Spatial and functional components of diversity in tropical mammals

全球各地的热带森林正在转变为人类主导的景观。尽管如此，热带森林仍然具有较高的群落内物种多样性（α多样性）和较高的群落间物种多样性（β多样性）。尽管这些热带群落中的哺乳动物生活在一系列空间尺度上，但大多数生物地理研究都集中在它们的α多样性上，这表明栖息地面积通常是与物种丰富度相关的主要因素（即较大的栖息地比较小的栖息地包含更多的物种）。最近的理论和实证研究表明，α多样性与景观和区域物种池密切相关，哺乳动物的功能特征，如体重，可以影响它们在破碎景观中的持久性。然而，由于对热带哺乳动物多样性的空间和功能成分的研究很少，许多重要的研究问题仍未得到解答。例如：与较小、较不复杂的栖息地相比，较大、较复杂的栖息地是否包含与景观物种群落更相似的物种群落？哺乳动物的某些功能特征是否导致了当地群落组成的变化？与森林破碎化相比，beta多样性是否在更大程度上控制着景观中的整体生物多样性？在接下来的5年里，我和我的学生将研究景观环境如何影响马达加斯加西北部24种非亲和性哺乳动物的多样性模式和过程。尽管从1955年到2014年，这个岛屿失去了44%的森林覆盖率，但它是一个生物多样性的热点，使其成为景观生态学研究的天然实验室。我们的研究目标将是确定：1)在人类主导的景观中，本地和景观物种池之间的关系；2)在破碎化景观中，某些功能特征是否导致某些哺乳动物物种比其他物种更常见；3)本地群落之间的物种多样性差异是否比森林破碎化更大程度上决定了景观多样性。我们将结合使用标准样线调查以及笼，桶和相机陷阱来收集数据以验证我们的假设。我们亦会进行植被采样和遥感数据分析，以更新我们过去10年在研究景观中完成的广泛生境地图。了解空间尺度如何影响生物多样性对保护生物地理学的研究至关重要，但缺乏关于热带非亲和性哺乳动物多样性模式和过程的数据。因此，我们的研究将有助于更好地了解栖息地的空间格局如何影响哺乳动物群落，提高马达加斯加珍稀哺乳动物保护工作的有效性，并为对保护生物地理学感兴趣的加拿大学生提供广泛的培训和研究机会。

Tropical forests are being converted to human-dominated landscapes across the planet. Nonetheless, tropical forests still contain high species diversity within communities (alpha diversity) and high species variations between communities (beta diversity). Although mammals in these tropical communities live across a range of spatial scales, most biogeographic research has focused on their alpha diversity, indicating that habitat area is typically the main factor associated with species richness (i.e. larger habitats contain more species than smaller habitats). Recent theoretical and empirical research indicates that alpha diversity is strongly related to landscape and regional species pools and that mammal functional traits, such as body mass, can influence their persistence in fragmented landscapes. However, many important research questions remain unanswered because the spatial and functional components of diversity have rarely been studied in tropical mammals. For example: Do larger, more complex habitats contain a species community more similar to that of the landscape species community than smaller, less complex habitats? Do certain functional traits of mammals result in variations in local community composition? And does beta diversity govern overall biodiversity across landscapes to a greater extent than forest fragmentation? Over the next 5 years, my students and I will study how landscape context influences diversity patterns and processes in 24 species of nonvolant mammals in northwest Madagascar. This island is a biodiversity hot spot, despite losing 44% of its forest cover from 1955-2014, making it a natural laboratory for research on landscape ecology. Our research objectives will be to determine: 1) the relationship between local and landscape species pools in human-dominated landscapes, 2) if certain functional traits result in some mammal species being more common than others in fragmented landscapes, and 3) if differences in species diversity between local communities determines landscape-wide diversity to a greater extent than forest fragmentation. We will use a combination of standard line transect surveys as well as cage, bucket, and camera traps to collect data to test our hypotheses. We will also conduct vegetation sampling and analysis of remote sensing data to update the extensive habitat mapping we have completed over the last 10 years in our study landscapes. Understanding how spatial scale influences biodiversity is critical for research in conservation biogeography, but there is a lack of data on diversity patterns and processes of nonvolant mammals in the tropics. Thus, our research will contribute to a better understanding of how spatial patterns of habitat influence mammal communities, increase effectiveness of conservation efforts for rare mammals in Madagascar, and provide extensive training and research opportunities to Canadian students interested in conservation biogeography.