EAPSI: Making Sense of Exceptional Diversity: Coexistence of Many Species in the Mammal Communities

地球上的生命分布并不均匀。尽管物种丰富度往往在热带地区达到顶峰，但生物多样性在全球和局部范围内都非常广泛。印度尼西亚苏拉威西岛的热带海洋岛屿拥有异常高的生物多样性，但鼠类啮齿动物(大鼠和小鼠)的动物群尤其引人注目。一些山地群落包含多达23种共生的小鼠物种，使这些群落成为地球上最丰富的密切相关哺乳动物群落。然而，尽管栖息地难以区分，但一些山地群落只有10个物种。适应性辐射理论预测，为了共存，群落中的物种不能依赖于相同的资源，而是通过饮食、栖息地或两者的变化来划分资源。为了了解资源是如何划分的，这个合作项目将从维多利亚博物馆哺乳动物馆长凯文·罗博士的实验室中的博物馆标本中生成高分辨率的形态和饮食数据。有了这些数据，这个项目将检验这样一种预测，即物种最丰富的群落成员比物种丰富较少的群落的成员存在于来自更广泛栖息地的更多样化的资源上。这个项目为国际合作提供了一个难得的机会，同时提供的证据将阐明一些群落是如何如此多样化的，这个问题自进化思想最早的日子以来就一直困扰着生物学家。适应性辐射理论预测，必须存在足够的生态空间，才能让密切相关的物种共存。计算群落中的生态体积可以解释资源是如何划分的。苏拉威西的小鼠啮齿动物(大鼠和小鼠)区系引人注目，一些山地群落包含多达23个共生物种。然而，这种多样性并不均匀地分布在整个岛屿上，一些山地群落只有10个物种。这种变异为群落组装提供了一个自然的实验，有可能阐明这些高度多样化的群落是如何起源和维持的。这项合作研究将使用维多利亚博物馆的自然历史收藏品来确定苏拉威西各地山地群落填充的生态位体积，以检验当地社区生态位体积将与物种丰富度正相关的预测。生态位体积将使用高分辨率骨骼成像(UCT扫描)、饮食同位素分析和消化道结构的新组合进行量化，提供苏拉威西啮齿动物如何利用现有资源的综合视角。这个合作项目将决定富裕群落是将更多物种放入相同的生态体积中，还是扩大总体积，潜在地解决进化生态学中一个长期存在的普遍问题。该奖项由东亚和太平洋夏季学院计划支持一名美国研究生的夏季研究，由NSF和澳大利亚科学院联合资助。

Life on the planet is not evenly distributed. Though species richness often peaks in the tropics, biological diversity is remarkably wide-ranging at both global and local scales. The tropical oceanic island of Sulawesi, Indonesia contains exceptionally high biodiversity, but the murine rodent (rats and mice) fauna is especially remarkable. Some montane communities containing up to 23 co-occurring murine species, making these the richest communities of closely related mammals on the planet. However, despite indistinguishable habitats, some montane communities contain as few as 10 species. The theory of adaptive radiation predicts that, in order to coexist, species in a community must not rely on the same resource, but instead partition resources through variation in diet, habitat, or both. To understand how resources are partitioned, this collaborative project will generate high-resolution morphological and dietary data from museum specimens in the lab of Dr. Kevin Rowe, Curator of Mammals at Museum Victoria. With these data, this project will test the prediction that members of the most species rich communities are existing on a greater diversity of resources from a wider variety of habitats than the less species rich communities. This project represents an exceptional opportunity for international collaboration while providing evidence that will illuminate how some communities are so diverse, an issue that has puzzled biologists since the earliest days of evolutionary thought.The theory of adaptive radiation predicts that adequate ecological space must exist for closely related species to co-occur. Calculating the ecological volume occupied in a community can explain how resources are partitioned. The murine rodent (rats and mice) fauna of Sulawesi is remarkable, with some montane communities containing up to 23 co-occurring species. However, this diversity is not distributed equally across the island, and some montane communities contain as few as 10 species. This variation provides a natural experiment in community assembly with the potential to illuminate how these hyperdiverse communities originate and are maintained. This collaborative research will use natural history collections at Museum Victoria to determine the ecological niche volume filled by montane communities across Sulawesi, testing the prediction that local community niche volume will be positively correlated with species richness. Niche volume will be quantified using a novel combination of high resolution skeletal imaging (uCT scans), isotopic analyses of diet, and the structure of digestive tracts, providing an integrated view of how Sulawesi rodents exploit available resources. This collaborative project will determine whether rich communities pack more species into the same ecological volume, or expand total volume, potentially resolving a long-standing, general question in evolutionary ecology.This award, under the East Asia and Pacific Summer Institutes program, supports summer research by a U.S. graduate student and is jointly funded by NSF and the Australian Academy of Science.