Landscape ecology of lemurs in Madagascar

对生态学至关重要的一个问题是了解动植物群落如何应对森林砍伐过程(森林损失、森林碎片化和边缘效应)。在世界许多地区，森林正变得越来越支离破碎，这导致边缘生境在每个支离物中所占的比例更大。对于马达加斯加的狐猴来说，这些问题具有特别的生态利益和保护关注，因为人类已经将岛上的大部分原始森林变成了草原。尽管已经开发出概念模型来预测动物群落将如何因森林丧失和碎片化而变化，但很少有人对热带哺乳动物的相关假设进行经验测试，更不用说针对树栖灵长类动物，如狐猴。我和我的学生建议重点研究马达加斯加西北部安卡拉芬西卡国家公园及其周围的两种昼夜食果性动物(Eulemur fulvus和Eulemur mongoz)、一种昼夜食叶/果食性动物(Propithecus Coqueli)、两种夜间食叶性动物(Lepemur edwardsi和Avahi ocsidentalis)以及三种夜间杂食性/果食性动物(Microcebus ravelobensis、Microcebus Murinus和Cheirogaleus medius)的景观生态学。我们将在6个3,000-4,000公顷的破碎森林景观中进行实地研究。首先，我们将检验物种-区域关系、集合种群模型和物种-碎片化区域关系的假设，以确定景观过程如何影响物种丰富度。物种-区域关系预测，更大的区域将包含更多的物种。在集合种群动态中，斑块占有率反映了灭绝速率和定殖率之间的动态关系，灭绝速率随面积的增大而减小，定殖率随隔离度的增大而减小。新提出的物种-碎片化区域关系将集合种群动态与物种-面积关系相结合，以预测物种灭绝风险如何影响高度碎片化景观中的物种丰富度。其次，我们将在景观水平上检验栖息地数量如何影响物种丰富度的另一种假设。该模型认为，无论灭绝-殖民动态如何，相同大小的样本碎片上的物种数量应随着每个样本点“局部景观”中的栖息地总量而增加。我和我的学生进行的研究是更好地理解人类改良景观中狐猴种群生态的基础。我们的研究也将是第一批在景观范围内收集和分析灵长类动物数据的研究之一；大多数研究只针对一个研究地点及其周围的几个物种群体。

A question of fundamental importance to ecology is understanding how plant and animal communities respond to deforestation processes (forest loss, forest fragmentation, and edge effects). Forests are becoming increasingly fragmented in many parts of the world, which result in edge habitats comprising a greater proportion of each fragment. For the lemurs of Madagascar, these issues are of particular ecological interest and conservation concern because humans have transformed most of the primary forests to grassland on the island. Although conceptual models have been developed to predict how animal communities will change due to forest loss and fragmentation, there are few empirical tests of the associated hypotheses on tropical mammals, let alone for arboreal primates, such as lemurs. My students and I propose to focus our research on the landscape ecology of two diurnal frugivores (Eulemur fulvus and Eulemur mongoz), one diurnal folivore/frugivore (Propithecus coquereli), two nocturnal folivores (Lepilemur edwardsi and Avahi occidentalis), and three nocturnal omnivores/frugivores (Microcebus ravelobensis, Microcebus murinus, and Cheirogaleus medius) at the fragment and landscape levels in and around Ankarafantsika National Park in northwest Madagascar. We will conduct our field research in six 3,000-4,000 ha fragmented forest landscapes. First, we will test hypotheses from species-area relationships, metapopulation models, and the species-fragmented area relationship to determine how landscape processes influence species richness. Species-area relationships predict that larger areas will contain more species. In metapopulation dynamics, patch occupancy reflects a dynamic relationship between extinction rates, which decrease with increasing area, and colonization rates, which decrease with increasing isolation. The newly proposed species-fragmented area relationship combines metapopulation dynamics with species-area relationships to predict how extinction risk influences species richness in highly fragmented landscapes.  Second, we will test an alternative hypothesis on how habitat amount influences species richness at the landscape level. This model holds that the number of species across sample fragments of the same size should increase with the total amount of habitat in the `local landscape' of each sample site, irrespective of extinction-colonization dynamics. The research that my students and I conduct is fundamental to a better understanding of the ecology of lemur populations in human-modified landscapes. Our research will also be amongst the first to collect and analyze data from primates at a landscape scale; most research has been on only a few groups of a species in and around one research site.