DISSERTATION RESEARCH: Do mesoherbivores drive Neotropical rainforest understory insectivorous bird declines by limiting availability of preferred foraging microhabitat?

热带鸟类非常容易受到森林碎片化的影响，其数量的减少往往归因于栖息地面积减少的直接影响。然而，这些鸟类几乎从一些大型森林碎片中消失了，但仍在附近较小的保护区中生存。栖息地大小提出的解释这些下降的其他机制(食物限制、扩散限制和鸟巢捕食)也无法解释在几个热带森林中观察到的令人费解的模式。这项拟议的研究调查了一个新的替代假说，以解释大片栖息地鸟类的下降，该假说有三个关键组成部分：(1)林下食虫鸟类更喜欢在被称为藤本植物的茂密的木质藤本植物上觅食；(2)有衣领的刺果抑制了藤本植物的密度，以及(3)失去合适的栖息地，因此，鸟类种群与杂果类密度相对应。这项研究将在巴拿马中部检验这一假设的三个组成部分，在那里，焦点鸟类和藤本植物的数量都有所增加，而珍稀鸟类的密度仍然很低。该项目的结果立即在中美洲的保护区得到了应用。参与该项目的研究生会说两种语言，并计划让巴拿马当地的土地所有者和管理者参与该项目。对当地社区的外展将包括鸟类鉴定和鸟类环志示范。来自通常在科学领域代表性较低的群体的本科生也将通过参与这项研究进行培训。

Tropical birds are highly vulnerable to forest fragmentation, and declines are often attributed to the direct effects of decreased habitat size. However these birds have nearly disappeared from some large forest fragments, but persist in smaller nearby reserves. Mechanisms other that habitat size proposed to account for these declines (food-limitation, dispersal-limitation and nest predation) also fail to explain the puzzling patterns observed in several tropical forests. The proposed research investigates a new, alternative hypothesis to account for bird declines in large habitat patches that has three key components: (1) understory insectivorous birds prefer to forage in dense woody vines called lianas; (2) collared peccaries suppress liana densities, and (3) loss of suitable habitat and, consequently, bird populations correspond with peccary densities. The study will test the three components of this hypothesis in central Panama, where both focal bird populations and lianas have increased while peccary densities remain low.Results from this project have immediate conservation applications in reserves across Central America. The graduate student involved is bilingual and plans to engage local land owners and managers in Panama in the project. Outreach to local communities will include bird identification and bird banding demonstrations. Undergraduate students from groups typically underrepresented in science will also be trained through participation in this research.