Collaborative Research: The effect of inbreeding on metapopulation dynamics of the giant kelp, Macrocystis pyrifera

了解种群在空间和时间上波动的原因是生态学家的极大兴趣，关于这一主题的知识在保护和环境管理方面具有广泛的应用。许多物种生活在高度分散的景观中，这一认识导致了集合种群理论的发展，该理论广泛适用于陆地和海洋系统。集合种群的概念最简单的形式是，适合当地种群的栖息地斑块要么被占用，要么不被占用，斑块之间的连通性可以“拯救”灭绝的当地种群。最近几项关于近亲繁殖的研究挑战了传统的观点，即生态因素是当地人口减少和最终灭绝的主要原因。然而，到目前为止，很少有调查在何种程度上近交衰退驱动当地人口动态的集合种群。巨型海带，Macrocystis pyrifera，是测试集合种群理论的理想系统，因为它发生在离散的斑块中，这些斑块在几年的时间尺度上经历频繁的局部扩张和扩张。研究人员将测试五个相关的假设，旨在确定南加州湾巨型海带的集合种群是否至少部分受到重复和异步的近亲繁殖衰退的影响。这项研究的动机是以前的调查结果，当地人口灭绝和灭绝模式的斑块大小和隔离程度，孢子传播和遗传连接的模式，以及近亲繁殖抑郁症的不良后果海带繁殖。该项目将：（1）评估南加州湾巨型海带种群近亲繁殖的程度和模式;（2）确定通过繁殖减少导致的近亲繁殖衰退对南加州湾巨型海带集合种群斑块动态模式的影响程度。最近的发展将极大地促进研究：（1）高度多态性微卫星标记的群体遗传学特征的巨型海带，（2）高分辨率的海洋学模型估计本地种群之间的连接巨型海带，和（3）一种新的方法，估计有效的人口规模为所有离散补丁的巨型海带在南加州湾使用Landsat卫星图像。更广泛的影响：巨型海藻森林是世界各地温带海洋浅礁的突出特征，也是地球上最具生产力的生态系统之一。巨型海藻本身为各种消费者提供食物和栖息地，其中许多消费者在商业和娱乐方面都很重要。因此，巨型海藻森林被自然资源保护者、资源管理者和决策者作为特别关注的生境，因为它们提供的生态系统服务具有很高的价值。主要研究人员有与政府机构合作制定旨在保护这些系统的管理计划的历史，这项研究的结果将有助于这些正在进行的努力。拟议的研究还将有助于学生培训和指导跨学科研究在本科生，研究生和博士后水平分布在3个不同的机构。主要研究人员将与UCSC和UCSB现有的外展计划合作，将他们的研究成果提供给K-12和中学后机构，教育工作者，社区团体和公众。

Understanding the causes for populations to fluctuate in space and time is of great interest to ecologists and knowledge on this topic has widespread application for conservation and environmental management. The recognition that many species live in highly fragmented landscapes led to the development of metapopulation theory, which is widely applicable to both terrestrial and marine systems. In its simplest form the concept of a metapopulation represents the idea that habitat patches suitable for local populations are either occupied or not and that connectivity among patches acts to "rescue" extinct local populations. Several recent studies on inbreeding have challenged the traditional belief that ecological factors are the primary causes of local population reduction and eventual extinction. However, to date there have been few investigations of the extent to which inbreeding depression drives local population dynamics in a metapopulation. The giant kelp, Macrocystis pyrifera, is an ideal system for testing metapopulation theory because it occurs in discrete patches that undergo frequent local extinctions and recolonizations on time scales of a few years. The investigators will test five related hypotheses aimed at determining whether the metapopulation of the giant kelp in the Southern California Bight is regulated at least in part by repeated and asynchronous episodes of inbreeding depression. This research is motivated by previous findings of the investigators on patterns of local population extinction and recolonization with respect to patch size and degree of isolation, patterns of spore dispersal and genetic connectivity, and the adverse consequences of inbreeding depression to kelp reproduction. This project will: (1) Assess the extent and pattern of inbreeding in populations of giant kelp in the Southern California Bight, and (2) Determine the extent that inbreeding depression via decreased reproduction contributes to the pattern of metapopulation patch dynamics of giant kelp in the Southern California Bight. The research will be greatly facilitated by recent developments of: (1) highly polymorphic microsatellite markers for characterizing the population genetics of giant kelp, (2) a high resolution oceanographic model for estimating connectivity among local populations of giant kelp, and (3) a novel method for estimating effective population size for all discrete patches of giant kelp in the Southern California Bight using Landsat satellite imagery. Broader Impacts: Giant kelp forests are prominent features on shallow reefs in temperate seas worldwide and are among the most productive ecosystems on Earth. Giant kelp itself provides food and habitat for a diverse assemblage of consumers many of which are commercially and recreationally important. Consequently, giant kelp forests are targeted by conservationists, resources managers and policy makers as habitats of special concern due to the high value ascribed to the ecosystems services that they provide. The principal investigators have a history of working with government agencies in developing management plans aimed at protecting these systems and findings from this research will contribute to these ongoing efforts. The proposed research will also contribute to student training and mentoring in interdisciplinary research at the undergraduate, graduate, and post doc levels spread across 3 different institutions. The principal investigators will partner with existing outreach programs at UCSC and UCSB to deliver the results of their research to k-12 and post-secondary institutions, educators, community groups and the general public.