EAGER: Linking functional traits to coexistence mechanisms in a novel assemblage

生态学提出的最大问题之一是，这么多不同种类的物种如何共存？物种之间以许多不同的方式相互作用。一些物种争夺食物或栖息地等资源，一些物种捕食或寄生其他物种，一些物种需要其他物种才能生存。考虑到所有这些关系，我们如何解释，甚至更好地预测，哪些物种将能够长期共存(即稳定共存)？这个问题在今天尤为重要，因为全球变化正在改变哪些物种正在相遇。生态学家已经设计了几种理论来解决物种如何共存的问题。例如，竞争食物的物种可能会通过同时食用不同类型的食物而共存。或者，物种可能更善于在不同类型的环境中获取食物，因此可能通过利用不同的微生境共存。如果物种在以不同方式利用资源或栖息地的特征上存在差异，那么特征差异可以用来预测物种是否以及如何共存。性状变异是否会以一致的方式预测所有类型的群落是否会以一致的方式共存，这是一个潜在的强有力的假设，如果是真的，研究人员将允许研究人员预测群落将如何随着时间的推移而变化以应对环境变化。原则上，这一假设应该适用于整个生命之树。然而，基本理论的关键方面只在少数几个研究系统中进行了测试，主要是植物和微生物。因此，这些想法的普遍性以及它们的全部影响仍未在动物界得到检验。这项研究将把形态学和生态学结合起来，以测试这些想法是否适用于蜥蜴群落。这项研究将通过为夏威夷大学的本科生提供研究培训，帮助扩大对科学的参与。夏威夷大学是美国最多元化的大学校园之一。研究策略是1)测量特征，2)根据特征差异和假设的共存机制产生对实验结果的预测，3)使用中观实验测试预测。所研究的物种是两种虎(Anolis carolinensis，A.sgrei)和一只日壁虎(Phelsum A Lasicauda)，它们都不是夏威夷原产的。蜥蜴将被引入有两种不同栖息地处理的实验围栏中。每个物种对猎物的消耗程度将在两种生境中作为R*的替代来衡量，R*是支持种群的最低资源水平。这将允许确定竞争能力中资源划分与空间异质性的重要性。对不同栖息地类型捕食造成的死亡率的监测将表明捕食者易感性的空间异质性在驱动共存方面的潜在作用。通过区分这些机制并将它们与特征联系起来，这项研究将具体生成和测试树栖蜥蜴群落中物种相互作用的结果预测，并更广泛地提供案例研究，以指导未来在大型动物中测试共存理论的工作。该奖项反映了NSF的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。

One of the biggest questions that ecology asks is, how can so many different kinds of species coexist? Species interact with each other in many different ways. Some species compete for resources like food or places to live, some eat or parasitize others, some need other species in order to survive. Given all of these relationships, how do we explain, or even better predict, which species will be able to live with each other long-term (i.e. stably coexist)? This question is particularly important today, as global changes are altering which species are encountering each other. Ecologists have devised several theories to address the question of how species coexist. For example, species that compete for food may coexist by eating different types of food when they co-occur. Or, species may be better at acquiring food in different types of environments, and so may coexist by using different microhabitats. If species differ in traits that allow them to use resources or habitats in different ways, then trait differences can be used to predict if and how species can coexist. Whether trait variation predicts coexistence in consistent ways across all types of communities is a potentially powerful hypothesis that if true would allow researchers to predict how communities will change over time in response to environmental change. In principle, this hypothesis should apply across the tree of life. However, key aspects of the underlying theory have only been tested in a handful of study systems, mainly plants and microorganisms. As a result, the generality of these ideas and therefore their full impact remains untested in animal communities. This research will integrate morphology and ecology to test whether these ideas can apply to a lizard community. This research will contribute to broadening participation in science by providing research training to undergraduate students from the University of Hawaii, one of the most diverse college campuses in the country. The research strategy is to 1) measure traits, 2) generate predictions for experimental outcomes based on trait differences and hypothesized coexistence mechanisms, and 3) test predictions using a mesocosm experiment. The study species are two anoles (Anolis carolinensis, A. sagrei), and a day gecko (Phelsuma laticauda), all of which are non-native to Hawaii. Lizards will be introduced to experimental enclosures with two different habitat treatments. The degree to which prey are differentially depleted by each species will be measured in the two habitats as a proxy for R*, which is the minimum resource level that can support a population. This will allow for determination of the importance of resource partitioning vs. spatial heterogeneity in competitive ability. Monitoring of mortality due to predation in the different habitat types will indicate the potential role for spatial heterogeneity in predator susceptibility in driving coexistence. By distinguishing among these mechanisms and connecting them to traits this research will generate and test predictions regarding the outcome of species interactions in arboreal lizard communities specifically, and more generally provide a case study to guide future work testing coexistence theory in macrofauna.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.