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够在零散的栖息地中稳定共存是理解维持生物多样性的关键。相似物种的共存--它们在食物链中处于同一水平，有着相似的生活史，并拥有共同的捕食者--需要某种形式的权衡，使每一种物种要么受到不同资源或敌人的限制，要么在空间、时间或两者的某些方面都是彼此的优势竞争对手。这个项目将阐明在美国缅因州海岸外一个岛屿上的一个淡水岩石池中，两种食草型浮游动物--巨尾浮游动物和脉动水蚤/幼体的生活史策略的差异。将研究每个物种的休眠和扩散，以确定这些差异是单独促进共存，还是与空间和时间变化结合起来促进共存。这项研究将在实验上测试一种物种是否在保持休眠方面更好，而另一种物种在分散方面是否更好，并将模拟这两种物种是否能够共存。该项目将通过现场助教奖学金和有指导的独立项目来培养一名博士生和多名本科生。这项研究将在附近的生物野外站向公众、K-12学生和来自许多机构的本科生传达。这项研究本身促进了科学的进步，并通过将其应用于零碎生境的生物多样性管理而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够在零碎的栖息地稳定共存是理解维持生物多样性的关键。相似物种的共存--在相同的营养水平下进食，有着相似的生活史，并共享捕食者--需要某种形式的权衡，使每一种物种要么受到不同资源的限制，要么受到不同敌人的限制，或者在空间、时间或两者的某些方面都是另一种物种的优势竞争者。在美国缅因州沿海的一个岛屿上的一个淡水岩池集合群落中，将阐明两种食草型浮游动物--巨尾水蚤和大型水蚤的生活史策略的差异。将审查和使用与每个物种休眠和扩散有关的生活史策略，以确定这些差异是单独促进共存，还是与时空变化结合起来促进共存。这项研究将通过实验测试(1)是否一个物种在保持休眠方面更好，而另一个物种在分散方面更好，以及(2)这是否允许这两个物种在这个元群落中共存，方法是测量必要的关系，将数学休眠-扩散模型参数化，以测试共存的条件。滞育卵的空间和时间分散率及其建立的成功率将通过储存由最初没有该物种的其他池包围的焦点池来衡量。这些数据将与人工中观和人工岩石池中的竞争结果数据结合在一起。除了加深我们对生物多样性维护的理解，该项目还将通过实地援助和有指导的独立项目来培训一名博士生和多名本科生。生物多样性可以应用于自然和人类活动分散的生境的管理。此外，有关该项目的信息将向浅滩海洋实验室的参观者传播，该实验室包括公众、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.