DISSERTATION RESEARCH: Scaling up From Individual Behavior to Composition of Communities in Tropical Forest Remnants

生境碎片化是指大片连续生境被分割成较小的片断(即“生境岛”或“斑块”)的过程，通常是由于人类活动造成的。理解为什么一些物种不能容忍生境片断化并从孤立的斑块中消失，而其他物种广泛分布并即使在偏远的片断中也存在，这是基础群落生态学研究和保护生物学的中心问题。一个关键的假设是，物种间扩散能力的差异强烈地影响着分布格局。物种在斑块之间移动的容易程度与它们在与世隔绝的群落中的存在之间的联系经常被假设，但很少有实验评估。这个项目的目标是揭示热带林下森林鸟类在一个由森林覆盖的岛屿组成的群岛中的扩散能力和群落组成之间的关系。这将通过评估限制扩散假说来实现，该假说指出：森林林下鸟类物种之间的行为或生理特征的差异，如穿越栖息地缺口的意愿或能力，解释了岛屿占据的生物地理模式。为了评估鸟类的分散能力，我将进行一系列简单的实验，用船将鸟类运送到远离大陆森林的不同距离，并将其放生，以记录它们成功飞回大陆的能力。初步结果表明，放飞试验中的最大飞行距离与每个物种居住的最孤立岛屿的距离之间存在很强的正相关关系。更广泛的科学影响是显而易见的：热带景观中碎片的连通性对于确保整个区域鸟群的持久性至关重要。如果没有栖息地走廊，鸟类可以在斑块之间移动，支离破碎的地貌将缺乏鸟类动物群的子集，而鸟类动物群是糟糕的分散者。

Habitat fragmentation is the process by which large areas of continuous habitat are divided into smaller pieces (i.e. "habitat islands" or "patches"), usually due to human activity. Understanding why some species are intolerant of habitat fragmentation and disappear from isolated patches, whereas other species are widely distributed and maintain a presence even in remote fragments is a central issue in both basic community ecological research and conservation biology. A key hypothesis is that differences in dispersal abilities among species strongly influence distribution patterns. The connection between how easily species move between patches and their presence in isolated communities has often been hypothesized but rarely experimentally evaluated. The goal of this project is to uncover the relationship between dispersal ability and community composition for tropical understory forest birds in an archipelago of forested islands. This will be accomplished by evaluating the Restricted Dispersal Hypothesis, which states: Variation in behavioral or physiological traits among species of forest understory birds, such as willingness or ability to cross a habitat gap, explains biogeographic patterns of island occupancy. To assess dispersal ability, I will conduct a series of simple experiments where birds are transported by boat to various distances away from mainland forest and released to document their abilities to fly successfully back to mainland. Preliminary results show a strong positive correlation between the maximum distance flown in release trials and the distance to the most isolated island inhabited by each species. Broader scientific impacts are clear: connectivity of fragments in tropical landscapes is critical to ensure persistence of entire regional avifaunas. Without corridors of habitat through which birds may move among patches, fragmented landscapes will lack the subset of avifaunas which are poor dispersers.