Developing a Regional Context for Rocky Subtidal Communities: Upwelling, Biotic Interactions and Diversity Regulation in the Galapagos Marine Reserve

群落生态学的基础是在相对较小的空间尺度上进行的研究。在海洋生态学中，基础的基石是对焦点区域的物种相互作用的分析，这些区域被输送营养物质、食物和下一代生物生殖繁殖的洋流所沐浴。因此，生活在当地地点的社区在一定程度上通过海洋过程在更大的空间尺度上联系在一起。了解这种联系的范围和规模对于社区生态学作为一种智力努力的发展至关重要，也对于预测沿海海洋生态系统的当地生物群将如何因全球变化步伐的加快而改变至关重要。后一种情况之所以适用，是因为全球大气过程调节着连接当地站点的洋流。虽然近二十年来，人们已经认识到有必要扩大海洋研究的空间范围，但在发展海洋底栖生态的区域海洋学观点方面进展缓慢，特别是对于潮下生态系统。本项目通过为生活在世界第二大海洋保护区加拉帕戈斯海洋保护区(GMR)的岛屿(岩壁)陡峭水下一侧的底栖生物群落建立区域背景，与这些更广泛的目标有关(Bustaente等人，2000年)。由于营养丰富的上升流和几乎完好无损的海洋食物网，GMR潮下生态系统为研究自下而上(即由食物资源驱动)与自上而下(捕食性)调节底栖群落的重要性提供了极好的机会。项目组的初步研究表明，社区变化的步伐特别快，那里的水流以迄今报告的一些最高上升速度(S，高达60厘米)沿着岩壁流动。实验设计被用来检验一般假设：底部？岩壁群落的向上和自上而下的控制可预见地作为上升流的函数而变化。与查尔斯·达尔文研究站新的SeaWiFS设施提供的每日高分辨率Chla图像相比，对GMR中心8个地点的上升流、叶绿素a、营养物和浮游动物浓度的定期测量将被置于更大的背景下。测量受到保护和暴露于食草动物的处理中的藻类积累将评估底栖藻类对潜在增强的上升流营养状况的反应。因为副动物群。无脊椎动物以浮游生物为食，将水柱的产生与较高的营养水平联系起来，建议通过实验测量5种附生动物及其消费者(蜗牛、海胆)的生长和补充，以检验自下而上和自上而下的联系的预测。主要的捕食者将被封闭起来，以评估物种相互作用的强度在上升流地点最大的假设，而摄像机将提供另一种衡量地点消费者压力变化的指标。最后，理论和观察表明，由于无脊椎动物的快速繁殖和对主要空间占有者的高度捕食，上升流地点的多样性和多样性周转率最高。通过在群落生态学、海洋学和保护生物学的十字路口工作，这项研究将增加我们对物种相互作用中的生产力和局部变异如何影响海洋保护区物种多样性的理解。这项提议的更广泛的好处是，它将直接有助于保护规划，培养博士生，并对本科生和研究生教学产生积极影响。

The foundation of community ecology has been constructed from studies conducted on relatively small spatial scales. In marine ecology, the building blocks of the foundation are analyses of species interactions at focal sites that are bathed by currents transporting nutrients, food and reproductive propagules of the next generation of organisms. Thus, the communities living at local sites are linked to some extent on larger spatial scales by oceanographic processes. Understanding the extent and scale of such linkages is essential for the growth of community ecology as an intellectual endeavor and also for predicting how local biota of coastal marine ecosystems will be modified by an increasing pace of global change. The latter situation applies because global atmospheric processes regulate the oceanic currents that couple local sites. Although the need to expand the spatial scale of marine research has been recognized for nearly two decades, progress in developing a regional oceanographic perspective in marine benthic ecology has been slow, particularly for sub-tidal ecosystems.This project herein relates to these broader goals by developing a regional context for benthic communities living on steep underwater sides of islands (rock walls) in the Galapagos Marine Reserve, (GMR) the second largest marine protected area in the world (Bustamente et al 2000). Due to nutritive upwelling currents and marine food webs that are nearly intact, GMR subtidal ecosystems provide an excellent opportunity to investigate the importance of bottom ?up (i.e. driven by food resources) vs top?down (predatory) regulation of benthic communities. Preliminary research by the project team indicates that the pace of community change is especially rapid where currents flow up rock walls at some of highest upwelling velocities reported (to 60 cm s) to date. An experimental design is used to test the general hypothesis that bottom? up and top ?down control of rock wall communities varies predictably as a function of upwelling. Regular measurement of upwelling currents, chlorophyll a, nutrient and zooplankton concentrations at 8 sites in the central GMR will be placed in a larger context by comparison to daily, high resolution images of chl a provided by the new SeaWIFS facility at the Charles Darwin Research Station. Measuring algal accumulation in treatments protected from and exposed to grazers will assess a response of benthic algae to the potentially enhanced upwelling nutrient regime. Because epifaunal. invertebrates feeding on plankton link water column production to higher trophic levels,, experiments are proposed to measure the growth and recruitment of 5 epifaunal species and their consumers (snails, sea urchins) to test the predictions of bottomup and top?down linkage . Key predators will be enclosed to evaluate the hypothesis that the strength of species interactions is greatest at upwelling sites while video cameras will provide another measure of site variation in consumer pressure. Finally, theory and observation suggest that the highest diversity and turnover of diversity occurs at upwelling sites due to rapid invertebrate production and high predation on primary space occupiers. By working at the crossroads of community ecology, oceanography and conservation biology, the research will increase our understanding of how productivity and local variation in species interactions influence species diversity in marine reserves. The broader merits of the proposal are that it will directly contribute to conservation planning, train a PhD student and positively impact undergraduate and graduate teaching.