Dissertation Research: Recruitment in a Large-Seeded Tropical Tree

9321553植物招募是植物产生后代(种子)以取代自己从而产生自我更新的生境的过程。种子传播是允许植物通过将种子分布到周围地区来“移动”的过程。大多数植物产生的种子比生存能力多得多，因为在扩散后，老鼠和其他啮齿动物会吃掉(因此会杀死)许多种子。有时，如果种子丰富，啮齿动物可能会储存一些多余的种子，供今年晚些时候食用。其中一些储存的种子可能会被遗忘，并可能发芽，在这种情况下，啮齿类动物扮演着“二级”传播者的角色。那些存活并发芽的种子面临着许多其他危险，如食草性昆虫和哺乳动物、霉菌和疾病以及倒下的树枝和树木。因此，植物更新是一个复杂的多阶段过程，涉及到与许多其他物种的相互作用。在正在迅速遭到破坏的热带雨林中，我们对植物的招募知之甚少，因此我们缺乏必要的信息来提出如何拯救和恢复这些森林的建议。%牛油茶(与鳄梨有关)是哥斯达黎加蒙特韦尔德附近山林中的一种常见树木。大的果实被吃掉，种子被相对较少的鸟类传播。尽管对一些近缘树种的种子散布进行了一些研究，但这些种子散布后的命运还不是很清楚。在这项研究中，我们将通过对玉米草幼苗的招募来确定一次扩散、二次扩散和种子捕食对幼苗建立的重要性。这项研究将提供一些关于种子传播过程中所涉及的复杂程度的第一批信息。这些信息将被证明对希望重建--甚至只是维护--自然栖息地的野生动物管理者很有用。我们将研究一系列复杂的种子散布者和捕食者之间的相互关系。每一个因素都在决定植物生存方面起着作用--问题是，这个作用有多重要？如果知道各种初级和次级播散剂的作用，就可以预测动物灭绝对种子播撒的影响。不断增加的种子传播和植物招募的知识将为理解热带森林如何“工作”提供另一块拼图。*

9321553 lLevey Plant recruitment is the process by which plants produce offspring (seeds) to replace themselves and thus produce a self- regenerating habitat. Seed dispersal is the process that allows plants to "move" by distributing the seeds throughout the surrounding area. Most plants produce many more seeds than can survive because after dispersal, mice and other rodents eat (and therefore kill) many of the seeds. Sometimes, if seeds are abundant, rodents may store some extra seeds to be eaten later in the year. A few of these stored seeds may be forgotten and may germinate, in which case the rodents are acting as "secondary" dispersers. Those seeds that survive and germinate face many other dangers, such as plant-eating insects and mammals, mold and disease, and falling branches and trees. Thus, plant recruitment is a complicated process of many stages and involves interactions with many other species. In tropical forests, which are being rapidly destroyed, we know very little about plant recruitment, and therefore we lack the information necessary to make recommendations about how to save and restore these forests.%%% Ocotea endresiana (related to avocados) is a common tree in the mountain forests near Monteverde, Costa Rica. The large fruits are eaten and the seeds dispersed by relatively few species of birds. Despite several studies on seeds dispersal of some related trees, the post-dispersal fate of these seeds is not well understood. In this study, recruitment of O.endresiana seedings will be examined to determine the importance of primary dispersal, secondary dispersal, and seed predation on seedling establishment.%%% This research will provide some of the first information on the degree of complexity involved in the seed dispersal process. Such information will prove useful to wildlife managers who hope to rebuild -- or even simply to maintain -- natural habitats. The interrelationships among a complex array of seed dispers ers and predators will be examined. Each one plays a role in determining plant survival -- the question is, how critical is that role? If the roles of various primary and secondary dispersers are known, then one can predict the effects of animal extinctions on seed dispersal. Increasing knowledge of seed dispersal and plant recruitment will provide another piece in the puzzle of understanding how tropical forests "work."***