Synthesis of Local Demography and Regional Connectivity in a Marine Fish Metapopulation

大多数大型海洋物种，包括大多数海底无脊椎动物和鱼类，都有两个阶段的生命史，其中成虫产卵，幼虫随洋流分散到新的地点。因此，生活在海底或海底附近的物种分布在集合种群中，集合种群是由幼虫扩散联系在一起的空间隔离的成年种群群。要深入了解海洋集合种群的动态，就需要了解以下方面的时空模式和联系：（1）当地种群之间幼虫连接的程度，（2）幼虫自我补充回到其出生种群的程度，（3）补充幼虫的生理条件，（4）相对人口统计率，（5）直接密度依赖的来源，即随着人口规模的增加，人均出生率下降和/或死亡率上升，（6）当地种群之间丰度变化的同步水平;（7）当地种群的环境，包括捕食者、竞争者和栖息地结构。本项目将调查巴哈马埃克苏马海峡双色雀鲷的这些现象。这一制度已成为许多相关研究的主题。该项目历时3年（研究物种的整整一代），包括五个相隔200公里的核心研究岛屿，以及相隔1000公里的外围采集点。五个中心问题，专注于相对于集合种群动态的模式和过程将得到解决：（1）什么是集合种群，包括埃克苏马声音的空间边界？(2)每个当地种群内的自我招募水平和当地种群之间幼虫连接的模式是什么？(3)当地人口之间的人口动态和人口比率有多同步？(4)幼虫连接和人口统计率之间的关系，包括密度依赖的任何模式？(5)当地种群之间的人口统计率差异与幼虫的生理条件、捕食者丰度、竞争者丰度和栖息地结构有何关系？这些问题将使用基于微卫星的遗传分配方法来测量幼虫的连接性和自我招募（分配测试，聚类方法，和亲子分析）;新定居者的条件和差异条件的人口后果相结合的实地和实验室分析;人口监测，以衡量当地招聘，增长，生存和生殖输出;当地居民和短暂的捕食者丰度，干扰竞争对手密度和珊瑚礁结构的生态措施;和矩阵人口建模，将这些因素连接到一个连贯的和预测的框架，以了解影响，驱动和调节人口动态的关键因素，在当地和集合种群规模。智力优势：了解集合种群的动态对以下方面很重要：（1）渔业生物学和管理，因为它提供了关于鱼类种群的空间明确动态和可持续性的详细信息;（2）防止海洋捕捞，因为它提供了有关机制的知识，使当地灭绝的种群可以通过同一物种的可生存的当地种群重新建立，和（3）一般的海洋养护，因为它提供了海洋保护区网络可能有效的生态机制的信息。教育和推广：本项目将资助4名研究生的博士研究，并涉及至少12名本科生。参与该项目将直接通过PI和研究生的教学活动，间接通过本科生现场助理的经验，促进海洋生态学和保护生物学的教育。

Most larger marine species, including most bottom-oriented invertebrates and fishes, have a two-stage life history, in which adults spawn larvae that disperse in ocean currents to new locations. Species that live on or near the seafloor are thus distributed in metapopulations, which are groups of spatially isolated adult populations linked by larval dispersal. Insight on the dynamics of marine metapopulations requires knowledge of spatial and temporal patterns of and linkages among: (1) the degree of larval connectivity among local populations, (2) the extent of self-recruitment of larvae back to their natal populations, (3) the physiological condition of recruiting larvae, (4) the relative demographic rates (including recruitment [= birth], growth, reproductive output, and death) of local populations, (5) sources of direct density dependence, whereby the per capita birth rate decreases and/or the death rate increases as population size increases, (6) the level of synchrony of variation in abundance among local populations, and (7) the environments of local populations, including predators, competitors, and habitat structure. This project will investigate these phenomena for the bicolor damselfish, Stegastes partitus, in the Exuma Sound, Bahamas. This system has been the subject of numerous relevant studies. The project spans 3 years (a full generation of the study species), and includes five core study islands separated by up to 200km, and peripheral collection sites separated on the scale of 1000km. Five central questions that focus on both pattern and process relative to metapopulation dynamics will be addressed: (1) What is the spatial boundary of the metapopulation that includes Exuma Sound? (2) What are the levels of self-recruitment within each local population and the patterns of larval connectivity among local populations? (3) How synchronous are population dynamics and demographic rates among local populations? (4) What are the relationships among local populations between larval connectivity and demographic rates, including any patterns of density dependence? (5) How are differences in demographic rates among local populations related to the physiological condition of settling larvae, predator abundance, competitor abundance, and habitat structure? These questions will be addressed using microsatellite-based genetic assignment methods to measure larval connectivity and self-recruitment (assignment tests, clustering methods, and parentage analysis); combined field and laboratory analyses of the condition of new settlers and the demographic consequences of differential condition; demographic monitoring to measure local recruitment, growth, survival, and reproductive output; ecological measures of local resident and transient predator abundance, interference competitor density, and reef structure; and matrix population modeling to link these factors into a coherent and predictive framework to understand the key factors that affect, drive, and regulate population dynamics at both local and metapopulation scales. Intellectual Merit: Understanding the dynamics of metapopulations is important to (1) fisheries biology and management because it provides detailed information regarding spatially explicit dynamics and sustainability of fish stocks, (2) prevent marine extinctions because it provides knowledge of the mechanisms whereby locally extinct populations can be re-established by viable local populations of the same species, and (3) marine conservation in general because it provides information on the ecological mechanisms whereby networks of marine protected areas may be effective.Education and outreach: This project will fund the PhD research of 4 graduate students, and involve at least 12 undergraduates. Participation in this project will promote education in marine ecology and conservation biology directly via the PI's and graduate students' teaching activities, and indirectly via the experiences of undergraduate field assistants.