Dissertation Research: Linking coexistence at local and regional scales by assessing a dormancy-dispersal tradeoff

了解物种如何以及是否能在一个分散的栖息地中稳定共存是理解生物多样性维持的关键。相似物种的共存？那些在食物链中处于同一层次的动物，有相似的生活史，共享捕食者？需要某种形式的权衡，比如每个人都受到不同资源或敌人的限制，或者每个人在空间和时间上都是另一个人的竞争对手。本项目将阐明两种食草浮游动物Moina macrocopa和Daphnia pulex/pulicaria在美国缅因州海岸附近岛屿的淡水岩石池中的生活史策略差异。每个物种的休眠和扩散将被检查，以确定这些差异是单独促进共存还是与空间和时间变化相结合。这项研究将通过实验测试一种物种是否更擅长保持休眠，而另一种物种是否更擅长分散，并将模拟这是否允许这两个物种共存。该项目将通过实地助教奖学金和指导独立项目培养一名博士生和多名本科生。该研究将在附近的生物野外站向公众、K-12学生和许多机构的本科生进行宣传。研究本身促进了科学的进步，并通过应用于破碎生境的生物多样性管理对国家福利产生影响；该项目还支持教育和多样性。了解物种如何以及是否能在一个破碎的栖息地中稳定共存是理解生物多样性维持的关键。相似物种的共存？在相同的营养水平上捕食，有相似的生活史，共同的捕食者？需要某种形式的权衡，比如每个人都受到不同资源或敌人的限制，或者每个人在空间和时间上都是另一个人的竞争对手。本文将在美国缅因州海岸外的一个岛屿淡水岩池元群落中阐明两种食草浮游动物Moina macrocopa和Daphnia pulex/pulicaria的生活史策略差异。与每个物种的休眠和扩散有关的生活史策略将被检查并用于确定这些差异是单独促进共存还是与空间和时间变化相结合。本研究将通过实验检验(1)一个物种是否更擅长保持休眠而另一个物种更擅长分散；(2)这是否允许这两个物种在这个元群落中共存，通过测量必要的关系来参数化一个数学的休眠-分散模型，以测试共存的条件。滞育卵的时空扩散率及其建立成功将通过在最初没有该物种的其他池周围放养焦点池来测量。这些数据将与人工中生态系统和人工岩石池中竞争结果的数据相结合。除了进一步加深我们对生物多样性维护的理解，这可以应用于自然和人为破碎的栖息地的管理，该项目将通过实地助教奖学金和指导的独立项目培养一名博士生和多名本科生。此外，有关这个项目的信息将传播给浅滩海洋实验室的参观者，其中包括公众、K-12学生和来自许多机构的本科生。

Understanding how and if species can coexist stably in a fragmented habitat where patches are connected by dispersal is key to understanding the maintenance of biodiversity. The coexistence of similar species?ones that feed at the same level in a food chain, have similar life histories, and share predators?requires some form of tradeoff such that each is either limited by different resources or enemies, or each is a superior competitor to the other at some points in either space, time, or both. This project will elucidate the differences in life-history strategies of two grazing zooplankton, Moina macrocopa and Daphnia pulex/pulicaria, in a freshwater rock-pools on an island off the coast of Maine, USA. The dormancy and dispersal of each species will be examined to determine if these differences promote coexistence either alone or in combination with spatial and temporal variation. This study will experimentally test whether one species is superior at remaining dormant while one species is superior at dispersing, and will model whether or not this allows these two species to coexist. This project will train one Ph.D. student and multiple undergraduate students through field-assistantships and mentored independent projects. The research will be communicated to the public, K-12 students, and undergraduates from many institutions at a nearby biological field station. The research itself promotes the progress of science and has implications for national welfare through application to the management of biodiversity of fragmented habitats; the project also supports education and diversity.Understanding how and if species can coexist stably in a fragmented habitat is key to understanding the maintenance of biodiversity. The coexistence of similar species?ones that feed at the same trophic level, have similar life histories, and share predators?requires some form of tradeoff such that each is either limited by different resources or enemies, or each is a superior competitor to the other at some points in either space, time, or both. The differences in life-history strategies of two grazing zooplankton, Moina macrocopa and Daphnia pulex/pulicaria, will be elucidated for a freshwater rock-pool metacommunity on an island off the coast of Maine, USA. Life history strategies relating to dormancy and dispersal of each species will be examined and used to determine if these differences promote coexistence either alone or in combination with spatial and temporal variation. This study will experimentally test (1) whether one species is superior at remaining dormant while one species is superior at dispersing, and (2) whether or not this allows these two species to coexist in this metacommunity by measuring the necessary relationships to parameterize a mathematical dormancy-dispersal model to test the conditions for coexistence. The spatial and temporal dispersal rates of diapausing eggs and their establishment success will be measured by stocking focal pools surrounded by other pools in which the species are initially absent. These data will be combined with data on competition outcomes in both artificial mesocosms and manipulated rock pools. In addition to furthering our understanding of the maintenance of biodiversity, which can be applied to the management of naturally and anthropogenically fragmented habitats, this project will train one Ph.D. student and multiple undergraduate students through field-assistantships and mentored independent projects. Furthermore, the information about this project will be disseminated to visitors to Shoals Marine Laboratory, which includes the public, K-12 students, and undergraduates from many institutions.