DISSERTATION RESEARCH: Effect of Forest Fragmentation on Seed Dispersal and Forest Regeneration in the Central Amazon

森林碎片化对种子传播和新热带森林更新的影响知之甚少。亚马逊地区的研究表明，与连续森林相比，潜在的种子传播者(灵长类、林下食果鸟类和蝙蝠)在森林碎片中的密度较低。相比之下，潜在的种子捕食者(陆地小型哺乳动物)更多样化，碎片更丰富。这些研究表明，种子的散布程度可能更低，而种子在小碎片中的捕食率更高，然而还没有研究对此进行测试。拟议的项目将第一次评估森林碎片化对亚马逊中部树木更新动态的影响，并将这些影响与植物-动物相互作用的修改量化地联系起来，这些修改被认为会影响树木更新。我们将在森林片断(1、10和100公顷)和连续森林中量化树苗物种丰富度和组成。我们将同时测量种子雨、种子捕食和草食。我们将测试森林碎片化通过果食性动物的损失对森林更新产生负面影响的假设，同时测试种子捕食、草食或边缘效应对树木更新的生物多样性和组成产生负面影响的替代假设。森林更新扩散限度的发现和测量将对新热带地区的土地管理产生重大影响，因为它将有助于估计允许持续更新的最小碎片大小和最大碎片隔离。这项研究还将确定种子传播者、捕食者和碎片大小之间的联系，这些联系可用于预测模型，以确定土地利用做法对本地森林物种的影响。

The effects of forest fragmentation on seed dispersal and neotropical forest regeneration are poorly understood. Research in the Amazon has shown that potential seed dispersers (primates, understory frugivorous birds, and bats) have lower densities in forest fragments compared to continuous forest. In contrast, potential seed predators (terrestrial small mammals) are more diverse and abundant in fragments. These studies suggest that seed dispersal may be lower, and seed predation higher in small fragments, however no studies have tested this. The proposed project will be the first to assess the effect of forest fragmentation on tree regeneration dynamics in the central Amazon and quantitatively relate these effects to modifications in plant-animal interactions that are hypothesized to influence tree regeneration. We will quantify tree seedling species richness and composition in forest fragments (1, 10, and 100 ha) and continuous forest. We will simultaneously measure seed rain, seed predation, and herbivory. We will test the hypothesis that forest fragmentation negatively affects forest regeneration through losses in frugivores and simultaneously test the alternate hypotheses that seed predation, herbivory, or edge effects negatively impact upon biodiversity and composition of tree regeneration. The discovery and measurement of dispersal limitation of forest regeneration will have major implications for land management in the neotropics, as it will contribute to estimates of the minimum fragment size and the maximum fragment isolation that can allow sustained regeneration. The research will also identify links between seed dispersers, predators, and fragment size that can be used in predictive models to determine the effects of land use practices on native forest species.