Collaborative Research: BEE: Niche evolution and the assembly of replicate island lizard faunas

为什么有些物种在群落中占主导地位，而另一些却很罕见？是什么决定了这样的生态成功是生物学中的一个基本问题。物种专门化的差异经常被用来解释成功。物种可以专注于几种资源（例如，一种食物），或者采用通才策略，并尝试使用多种资源。然而，一个单一的物种可能只专注于一种食物类型，但就它所处的栖息地而言，它是一个通才。由于这种复杂性，专家策略何时是有益的尚不清楚。这个项目试图通过研究西印度群岛上的蜥蜴群落来了解有利于专家的条件。西印度群岛社区的遗址包含一到八个物种，每个岛屿上都有不同的物种。首先，研究人员将通过量化蜥蜴的丰度来衡量物种的成功程度。其次，他们将根据蜥蜴的饮食、耐受的温度和栖息地来衡量它们的专业化程度。第三，研究人员将研究物种之间的进化关系，以评估专家进化的速度。最后，他们将测量食物资源、温度和栖息地的共同程度。该研究项目将支持本科生和研究生的培训，并促进高中的科学教育。此外，它将通过与艺术家合作，以研究为基础创作艺术，探索新的科学交流方式。专业化在决定生态和进化成功方面的作用一直备受争议。权衡是否会让通才“样样通，样样不精”——沦落为生态社区的脚注？或者，专家是否局限于稀有或不太理想的资源，以至于通才在数量上占主导地位？同样，专家是如何进化的也不清楚。生态位的扩张和收缩在宏观进化时间内是不稳定的吗？还是动物进化的阶段很重要，比如在适应性辐射中，早期的物种形成事件更有可能产生通才，而专才只在物种饱和的晚期形成？为了回答这些问题，本研究考察了大安的列斯群岛的蜥蜴适应辐射。研究人员使用标记再捕获法来量化牙买加、波多黎各和伊斯帕尼奥拉岛上两种地理上截然不同的动物群的当地群落结构。每个岛屿的动物群在进化上是独立的，但却反复进化出许多具有相似生态质量的物种。研究人员将通过测量每个物种的生态位位置（如最常使用的资源）和宽度（如使用资源的跨度）来量化生态相似性，这些生态相似性沿着热、植被结构和饮食轴。这样做可以让研究人员检验生态位宽度与生态群落优势相对应的假设。通过将生态位信息与系统发育关系结合起来，研究人员将解决生态位宽度在宏观进化时间内的不稳定性。最后，研究人员将量化每个群落和岛屿中可用的热、结构和饮食生态位空间，以评估通才是否在年轻、多样性较低、有充足未使用生态位空间的群落中更成功。该项目将为专业化进化的生态基础提供新的见解，测试长期存在的假设，并为这些假设在进化复制动物群中的普遍性提供见解。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Why do some species dominate communities while others are rare? What determines such ecological success is a fundamental question in biology. Differences in species’ specialization are often used to explain success. Species can either specialize on a few resources (e.g., one type of food), or employ a generalist strategy, and try to use many. However, a single species might specialize on one food type, but be a generalist in terms of the habitats that it’s found in. Because of this complexity it’s still unclear when a specialist strategy is beneficial. This project seeks to understand the conditions that favor specialists by examining lizard communities on islands in the West Indies. Sites in the West Indies communities contain one to eight species, with different species on each island. First the researchers will gauge how successful species are by quantifying lizard abundances. Second, they will measure lizard specialization with regards to their diets, the temperatures they tolerate, and the habitats they use. Third, the researchers will look to the evolutionary relationships between species, to assess how fast specialists evolve. Finally, they will measure how common food resources, temperatures, and habitats are. The research program will support undergraduate and graduate student training and promote science education in high schools. Further, it will explore new ways to communicate science by working with an artist to create art based on the research. The role of specialization in determining ecological and evolutionary success has been long debated. Do trade-offs render generalists ‘jacks-of-all-trade but masters-of-none’—relegated to footnotes in ecological communities? Or, are specialists restricted to rare or less desirable resources, such that generalists are numerically dominant? Likewise, it is unclear how specialists evolve. Is niche expansion and contraction labile over macroevolutionary time? Or does the stage of a fauna’s evolution matter, such that during adaptive radiations early speciation events are more likely to produce generalists, with specialists only forming in late-stage, species-saturated communities? To answer these questions this research examines the Anolis lizard adaptive radiation in the Greater Antilles. The researchers use mark-recapture to quantify the structure of local communities on Jamaica, Puerto Rico, and two geographically distinct faunas on Hispaniola. Each islands’ fauna is evolutionarily independent, but has nevertheless repeatedly evolved many species with qualitatively similar ecologies. The researchers will quantify ecological similarities by measuring the niche positions (e.g. most frequently used resource) and breadths (e.g. span of resources used) of each species along thermal, vegetation structural, and dietary axes. Doing so allows the researchers to test the hypothesis that niche breadth corresponds to dominance in ecological communities. By combining niche information with phylogenetic relationships, the researchers will then address how labile niche breadths are over macroevolutionary time. Lastly, the researchers will quantify available thermal, structural, and dietary niche space availability in each community and island to assess whether generalists are more successful in younger and less diverse communities with ample unused niche space. This project will provide novel insights into the ecological underpinnings of the evolution of specialization, testing long held hypotheses and offering insights into the generality of these hypotheses across evolutionarily replicated faunas.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.