Cascading effects of predator diversity in a marine food web

知识价值：海洋生物多样性的一般意义已被广泛接受。例如，有几个令人信服的例子说明了遗传、物种和功能群体多样性在调节底栖海洋栖息地的群落生产力、入侵性和稳定性方面的重要性。这样的实证研究和基础生态学理论支持了保护生物多样性应该是保护的重中之重的主张。然而，由于对捕食者多样性影响的实验研究很少，我们无法预测，甚至可能无法识别捕食者灭绝的级联效应。由于过度捕捞和栖息地丧失，几乎所有水生和陆生群落的脊椎动物捕食者的多样性都下降了，有时甚至是急剧下降。这一现象在一些海洋生态系统中得到了充分的记录，在这些生态系统中，过度捕捞使顶级捕食者的生物量减少了85%，物种丰富度减少了10-50%。为了了解这些变化对海洋捕食者组成和多样性的影响，我们显然需要开始在海洋生态系统中进行相关的实验。本研究将通过控制北卡罗莱纳州底栖河口食物网的结构，确定捕食者组成和多样性在低营养水平上的级联效应。研究人员将利用大型藻类、大型无脊椎食草动物、甲壳类和脊椎动物捕食者的多样性和充分研究的群落，在野外和室外中生态环境中进行实验，以回答三个基本问题：问题1：捕食者的身份和丰富度如何直接影响食草动物群落？问题2：捕食者身份和丰富度如何间接影响植物群落和初级生产？问题3：猎物迁徙是否介导了捕食者多样性效应？更广泛的影响：该项目将扩大弗吉尼亚海洋科学研究所（VIMS）和北卡罗来纳大学海洋科学研究所（IMS）的研究人员在海洋植物和食草动物生物多样性与生态系统功能之间关系方面的合作。这项研究将是任何生态系统中同类研究的第一次，并符合美国国家科学基金会生物海洋学计划强调的海洋系统生物多样性特别主题。研究结果将有助于科学家和政策制定者了解捕食者多样性下降的后果，并可能通过帮助保护类似的系统而造福社会。其他更广泛的影响将来自几项外展活动，包括：对中学生和高中生的指导，与莫尔黑德天文馆和科学中心组织的夏季海洋生态儿童营地，以及与州渔业管理人员和当地渔民的密切合作。

Intellectual merit: The general significance of marine biodiversity is widely accepted. For example, there are several compelling examples of the importance of genetic, species, and functional group diversity in regulating community productivity, invasibility, and stability in benthic marine habitats. Such empirical research and basic ecological theory support the assertion that preserving biodiversity should be a top conservation priority. Yet because there have been few experimental investigations of the effects of predator diversity, we cannot predict and may not even recognize the cascading effects of predator extinctions. The diversity of vertebrate predators has declined, sometimes precipitously, in nearly all aquatic and terrestrial communities as a result of over harvesting and habitat loss. This phenomenon is especially well documented in some marine ecosystems where over fishing has reduced top predator biomass by 85% and species richness by 10-50%. To understand the consequences of these changes in marine predator composition and diversity we clearly need to begin to perform relevant experiments in marine ecosystems. This study will determine the cascading effects of predator composition and diversity on lower trophic levels by manipulating the structure of a benthic estuarine food web in North Carolina. Using a diverse and well-studied community of macroalgae, macroinvertebrate herbivores, and crustacean and vertebrate predators, the investigators will perform experiments in the field and in outdoor mesocosms to answer three basic questions: Question 1: How does predator identity and richness directly affect herbivore communities? Question 2: How does predator identity and richness indirectly affect plant communities and primary production? Question 3: Does prey immigration mediate predator diversity effects? Broader impacts: This project will expand ongoing collaboration between researchers at the Virginia Institute of Marine Science (VIMS) and the UNC's Institute of Marine Science (IMS) on the relationships between marine plant and herbivore biodiversity and ecosystem functioning. This research will be the first of its kind in any ecosystem and fits within the Biological Diversity in Marine Systems special theme of emphasis of the NSF Biological Oceanography Program. The results will help scientists and policy makers understand the consequences of declining predator diversity, potentially benefiting society by helping to conserve similar systems. Additional broader impacts will result from several outreach activities including: the mentoring of middle and high school students, summertime marine ecology children's camps organized with the Morehead Planetarium and Science Center, and a close collaboration with state fisheries managers and local fishers.