Long-term and interactive effects of seaweed diversity and herbivory on intertidal community structure and functioning

海藻多样性和草食性对潮间带群落结构和功能的长期交互影响

• 批准号: 0850707
• 负责人: John Stachowicz
• 金额: $ 52.26万
• 依托单位: University of California-Davis
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-03-01 至 2014-02-28
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0850707&HistoricalAwards=false
• 关键词: Long; term; interactive; effects; seaweed

Stimulated in part by rapid changes in the biological composition and richness of most of Earth's ecosystems, considerable theoretical and empirical research has focused on understanding the effects of species richness on communities and ecosystems. This research has resulted in major advances and has shown that diversity can affect ecosystem processes. However, we are currently limited in our ability to draw generalities regarding these effects that transcend ecosystems and to apply this knowledge to conservation and management efforts because: (1) most experiments are of short duration and relatively few are conducted under field conditions on natural substratum; and (2) most experiments manipulate only diversity and so cannot assess the strength of diversity relative to other known drivers of ecosystem functioning. Previous NSF-funded work found that species diversity of seaweeds does increase the accumulation of producer biomass and the diversity and richness of mobile invertebrates associated with those seaweeds. In this project, the investigator will examine the interactive effects of plant and grazer richness on seaweed productivity and assemblage recovery from disturbance by (a) continuing our ongoing diversity manipulations (b) nesting additional experiments manipulating grazers within these plots, and (c) performing new experiments to examine effects of grazer richness on algal assemblages. The main experiment consists of 72 1.5 m diameter plots in the rocky intertidal at Bodega Bay, California, split into 6 different treatments: a monoculture of each of the 4 algal species that comprise 85% of the algal cover in our system; a 4-species polyculture, and an unmanipulated control plot. The PI created these "diversity" plots by weeding under the auspices of a previous NSF grant. Objectives of this project are: (1) To nest within the diversity plots smaller cleared areas that either allow or prohibit access by grazers in order to test the interactive effects of algal diversity and herbivory on recovery of the algal assemblage from disturbance (or resilience). (2) To conduct a separate combined additive and replacement series experiment to examine the effects of herbivore identity and richness on algal recruitment and succession. (3) While the nested grazer-exclusion experiment is in progress, to continue weeding and collecting data in the uncleared portion of these plots as a continued test of the univariate effect of algal richness on the cover of algae and sessile invertebrates, and on mobile invertebrate abundance, richness, and diversity. Together with previous results, this will produce a 7 year record of the effects of seaweed richness on rocky intertidal communities, which will then be correlated with archived environmental data. (4) After the nested grazer exclusion experiment is complete, to cease weeding plots and track their reinvasion by weeded species in order to evaluate the mechanisms maintaining diversity of perennial algae.Understanding the consequences of simultaneous changes in grazer abundance or diversity and algal diversity as well as the long-term effects of both on the resilience of algal communities in the face of disturbance will provide a better understanding of both the consequences of human encroachment into these habitats and the appropriate management efforts needed to minimize impacts and maintain ecosystem functioning. This is especially critical given that harvesting and trampling by humans are altering the diversity and composition of herbivores and algae in the California rocky intertidal zone. The PI recently briefed legislative and agency staff in California on the results of previous NSF work on the consequences of marine biodiversity, so there is interest from policymakers. The PI will continue to work with outreach groups like COMPASS and the Aldo Leopold Leadership Program to help disseminate the findings of this research as broadly as possible to the general public and decision-makers. In addition, through outreach efforts such as the Bodega Marine Lab Open House and visits to local schools the investigator will continue to foster public understanding of the importance of maintaining biodiversity and more generally of how science works. Finally, this project will develop future scientists including a technician, graduate and undergraduate researchers including those from underrepresented groups.

在地球生态系统的生物组成和丰富程度迅速变化的刺激下，大量的理论和实证研究集中在了解物种丰富程度对社区和生态系统的影响。这项研究取得了重大进展，并表明多样性可以影响生态系统进程。然而，我们目前的能力是有限的，以得出关于这些影响的一般性，超越生态系统和应用这些知识的保护和管理工作，因为：（1）大多数实验是短期的，相对较少的是在野外条件下进行的自然基质;（2）大多数实验只操纵多样性，因此无法评估多样性相对于其他已知生态系统功能驱动因素的强度。以前NSF资助的工作发现，海藻的物种多样性确实增加了生产者生物量的积累以及与这些海藻相关的移动的无脊椎动物的多样性和丰富性。在这个项目中，研究人员将研究植物和食草动物丰富度对海藻生产力和组合恢复干扰的相互作用，（a）继续我们正在进行的多样性操作（B）嵌套额外的实验操纵这些地块内的食草动物，和（c）进行新的实验，以研究食草动物丰富度对藻类组合的影响。主要实验包括72个1.5米直径的地块在岩石潮间带博德加湾，加州，分为6个不同的治疗：单一的4种藻类，包括85%的藻类覆盖在我们的系统，一个4种混养，和一个未操纵的控制地块。PI通过在先前的NSF资助下除草来创建这些“多样性”地块。本项目的目标是：（1）在多样性样地内筑巢，允许或禁止食草动物进入较小的清除区域，以测试藻类多样性和草食动物对藻类组合从干扰中恢复（或恢复力）的相互作用。(2)进行一个单独的组合添加剂和替代系列实验，以检查草食动物的身份和丰富度对藻类补充和演替的影响。(3)虽然巢式放牧排除实验正在进行中，继续除草和收集数据，在这些地块的未清除部分作为一个持续的测试藻类丰富度的单变量影响覆盖藻类和固着无脊椎动物，和移动的无脊椎动物的丰度，丰富度和多样性。加上以前的结果，这将产生一个7年的记录海藻丰富的岩石潮间带群落的影响，然后将与存档的环境数据。(4)在巢式食草动物排除实验完成后，停止对地块除草，并跟踪已除草物种的再入侵，以评估维持多年生藻类多样性的机制。了解食草动物丰度或多样性和藻类多样性同时变化的后果，以及长期的这两个方面对藻类群落在面对干扰时的恢复力的长期影响，将使我们更好地了解人类侵入这些栖息地的后果以及为尽量减少影响和维持生态系统功能所需的适当管理努力。考虑到人类的收获和践踏正在改变加州岩石潮间带食草动物和藻类的多样性和组成，这一点尤为重要。PI最近向加州的立法和机构工作人员简要介绍了NSF以前关于海洋生物多样性后果的工作成果，因此政策制定者对此感兴趣。PI将继续与COMPASS和Aldo Leopold Leadership Program等外展团体合作，帮助尽可能广泛地向公众和决策者传播这项研究的结果。此外，通过博德加海洋实验室开放日和访问当地学校等外联活动，调查员将继续促进公众了解维护生物多样性的重要性，以及更广泛地了解科学如何运作。最后，该项目将培养未来的科学家，包括技术人员，研究生和本科生研究人员，包括那些代表性不足的群体。