BEE: The Evolution of Fluctuation-Dependent Species Coexistence

了解相似物种如何共存一直是生态学的核心问题。这个问题很重要，因为物种多样性是自然生态系统的一个决定性特征。对这个问题的传统答案集中在物种在非波动环境中使用的资源类型方面的差异。在这种范式下，当进化使物种在资源利用方面不那么相似时，它可以促进物种共存。然而，自然生态系统并不是恒定不变的，最近人们对理解环境中的时间变化以及物种对这种变化的反应差异如何导致有利于共存的条件产生了兴趣。虽然我们在理论上了解这些波动依赖机制，但我们对它们是否能促进自然种群中的物种共存知之甚少。我们对进化如何促进或阻碍这种波动依赖机制的了解更少。本研究利用自然界中的实验进化研究以及人工流中的数学模型和实验来解决这些问题。这项研究将每年吸引38名来自不同背景的年轻科学家参加青年科学家培训计划。青年科学家获得的研究经验，是通过在生态学，进化和统计培训的补充。研究人员还将通过在线推广网站吸引公众参与，并将通过移动的游戏，社交媒体和基于该系统的教师培训模块开发生态学和进化方面的培训。这项工作将为自然群落中依赖波动的共存机制提供多管齐下的测试，并调查它们如何进化。在这样做的过程中，这项工作将综合生态学和进化生物学的思想。这项研究利用了自然实验室提供的结构流社区在特立尼达，西印度群岛的鱼类群落包括特立尼达孔雀鱼和哈特的鳉鱼或哈特的鳉鱼本身。当孔雀鱼入侵只有鳉鱼的群落时，就形成了鳉鱼-孔雀鱼群落。先前的研究表明，在这些入侵之后，孔雀鱼和鳉鱼在生活史和资源利用方面迅速进化出差异。这些溪流也是季节性很强的，有明显的旱季和雨季。鳉鱼和孔雀鱼对这些季节性波动的反应不同吗？孔雀鱼适应旱季条件吗？鳉鱼适应雨季条件吗？如果是这样，那么这种差异为两个物种的共存提供了一条途径。本研究还将讨论这些波动依赖机制相对于传统波动独立机制的重要性，并确定这些贡献如何通过社区的形成而改变。这项研究将利用结构化模型，人工流因子实验和稳定同位素工作在自然生态系统中复制实验进化研究。与此同时，数学模型将提供一个框架，将物种共存理论与进化理论联系起来。该奖项反映了NSF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。

Understanding how similar species coexist has been a central question in ecology since its inception. The question is important because species diversity is a defining characteristic of natural ecosystems. Traditional answers to this question focus on how species differ in the types of resources they use in non-fluctuating environments. Under this paradigm, evolution can facilitate species coexistence when it makes species less similar in their resource use. However, natural ecosystems are not constant, and there has been recent interest in understanding how temporal variation in the environment, and differences in how species respond to this variation, can lead to conditions that favor coexistence. While we know about these fluctuation-dependent mechanisms in theory, we know little about whether they can promote species coexistence in natural populations. We know even less about how evolution either facilitates or impedes such fluctuation-dependent mechanisms. This research attacks these questions by leveraging studies of experimental evolution in nature together with mathematical models and experiments in artificial streams. The research will engage 38 young scientists from diverse backgrounds per year in the Young Scientist Training Program. The Young Scientists gain research experience that is complemented by training in ecology, evolution, and statistics. The researchers will also engage the public through an online outreach website and will develop training in ecology and evolution through mobile gaming, social media, and teacher training modules based on this system.This work will provide a multipronged test of fluctuation-dependent coexistence mechanisms in natural communities and investigate how they evolve. In doing so, this work will synthesize ideas in ecology and evolutionary biology. This research takes advantage of the natural laboratory provided by the structure of stream communities in Trinidad, West Indies where fish communities consist of either Trinidadian guppies and Hart’s killifish or Hart’s killifish by themselves. Killifish-guppy communities are formed when guppies invade communities with only killifish. Prior research has shown that following these invasions, guppies and killifish rapidly evolve differences in their life histories and resource use. These streams are also highly seasonal with pronounced dry and wet seasons. Do killifish and guppies respond differently to these seasonal fluctuations? Are guppies adapted to dry season conditions and killifish to wet season conditions? If so, then this difference provides an avenue for the two species to coexist. This research will also address how important these fluctuation-dependent mechanisms are relative to traditional fluctuation-independent mechanisms and identify how these contributions change through the formation of the community. This research will leverage replicated experimental evolution studies in natural ecosystems with structured models, factorial experiments in artificial streams, and stable isotope work. At the same time, the mathematical models will provide a framework for linking theory on species coexistence with evolutionary theory.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.