DISSERTATION RESEARCH: Linking mechanism to pattern in community assembly: ant-mediated seed dispersal in tropical pioneer trees

生态学的一个中心目标是理解为什么物种生活在它们生活的地方。我们已经知道，不同的物种对生存、生长和繁殖有不同的要求。例如，有些树可以在阴凉处茁壮成长，而另一些树则需要大量的阳光。这些喜光的树木被称为“先锋”物种，因为它们通常是在扰动推翻曾经生长在那里的大树后第一个殖民的物种。它们的种子是如何到达那里的？它们要么在一个地区阳光充足后分散，要么更早分散，埋在土壤中，“等待”上面的树木死亡。在这两种情况下，植物通常依靠动物来运送种子。蚂蚁是最重要的种子传播者之一，因为它们既移动种子，又把种子“种”到土壤里。科学家们对蚂蚁种子传播的了解大多来自于对蚂蚁提供食物奖励的种子的研究。然而，大多数植物的种子，包括那些最重要的商业作物的种子，并不为蚂蚁提供食物奖励。进行这项研究的科学家们发现，蚂蚁可能会移动这些类型的种子，尽管没有奖励。他们认为蚂蚁被化学物质“欺骗”，携带了气味很好但不能吃的种子。这个项目的目标是测试这个想法，并找出气味好的化学物质可能是什么。研究结果将帮助土地管理者了解植物是如何迁移到新的地方的，这是森林恢复的一个重要过程。这项研究将使用一种热带树种和一种常见的地栖蚂蚁来确定可能促进种子传播的化学线索。该方法包括分离、鉴定、合成和实地测试种子提取物，以确定哪些化学物质吸引蚂蚁。种子提取物将在热带和温带环境中进行测试，以帮助确定哪些物种参与了蚂蚁介导的种子传播。研究结果将有助于指导植物保护、恢复和入侵物种管理的策略。此外，研究生将接受实验室技术和实地研究方面的指导。

A central goal of ecology is to understand why species live where they do. We already know that different species have different requirements to survive, grow, and reproduce. For example, some trees can thrive in the shade whereas others need lots of sunlight. These light-loving trees are called "pioneer" species because they are usually the first to colonize open areas after a disturbance topples large trees that once grew there. How do their seeds get there? Either they are dispersed after an area becomes sunny or they are dispersed much earlier, become buried in the soil, and "wait" for trees above them to die. In both cases, plants often rely on animals to move their seeds. Ants are one of the most important seed dispersers because they both move seeds and "plant" them in the soil. Most of what scientists know about seed dispersal by ants comes from studies investigating seeds that provide a food reward for the ants. However, most plant seeds, including those of most commercially important crops, do not provide a food reward for ants. The scientists doing this study have discovered that ants may move these types of seeds, despite the lack of a reward. They think that ants are chemically "tricked" to carry seeds that smell good but can't be eaten. The goal of this project is to test this idea and figure out what the good-smelling chemicals may be. Results will help land managers understand how plants move into new places, which is an important process in forest restoration. This research will use a tropical tree species and a common, ground-dwelling ant to determine possible chemical cues that promote seed dispersal. The approach includes fractioning, identifying, synthesizing, and field-testing seed extracts to identify which chemicals attract ants. Seed extracts will be tested both in tropical and temperate environments to help determine which species engage in ant-mediated seed dispersal. The results will help guide strategies for plant conservation, restoration, and invasive species management. In addition, a graduate student will be mentored in laboratory techniques and field research.