Dissertation Research: Neighborhood Effects on Seed Dispersal of a Neotropical Mistletoe

依赖食果鸟类进行种子传播的结果植物可能会经历重要的适应性后果，这是由于邻近环境对鸟类觅食运动的影响。鸟类对水果资源可用性空间格局的响应因此，这些模式将影响种子沉积模式。邻域效应对种子传播的影响尚未得到研究。本研究考察了这些对哥斯达黎加Monteverde牧场树上热带槲寄生物种的影响。从单株角度看三个扩散阶段的邻域效应利用一系列高密度和低密度宿主和槲寄生社区（约1公顷）来确定鸟类的访问、访问期间的行为和访问后的运动。槲寄生为检查种子传播提供了很好的系统，因为鸟类的种子沉积可以直接观察到，而且作为寄生虫，它们有独特的传播要求。该研究系统提供了一个独特的机会来检查这些影响，因为宿主和槲寄生在现场的安排。这项研究还将提高对这些很少被研究的热带物种的一般认识。随着森林的不断消失，受干扰的栖息地，如提议的地点，在新热带地区变得越来越重要，对这些栖息地中生态相互作用的理解也同样变得越来越重要。在森林被砍伐的地区，槲寄生可能是严重的害虫，那里大多数易感的树木都没有倒下；因此，本研究既有基础意义又有应用价值。

Fruiting plants that rely on frugivorous birds for seed dispersal may experience important fitness consequences resulting from neighborhood influences on bird foraging movements. Birds respond to spatial patterns of fruit resource availability; thus these patterns will influence seed deposition patterns. Neighborhood effects on seed dispersal have not been studied. This research examines these effects on a tropical mistletoe species in pasture trees at Monteverde, Costa Rica. Neighborhood effects from the individual plant perspective, on three stages of dispersal; bird visitation, behavior during visits, and post- visitation movements, using an array of high and low density host and mistletoe neighborhoods (ca. 1 ha) will be determined. Mistletoes provide good systems for examining seed dispersal because bird deposition of seeds can be observed directly, and, as parasites, they have unique dispersal requirements. The study system provides a unique opportunity to examine these effects because of the arrangement of hosts and mistletoes at the site. The study will also enhance general knowledge of these little-studied tropical species. Disturbed habitats, such as the proposed site, are of increasing importance in the neotropics with the continuing loss of forests, and an understanding of ecological interactions in these habitats is likewise of increasing importance. Mistletoes can be serious pests in deforested areas where mostly susceptible trees are left standing; thus, this study is of both basic and applied interest.