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建立起来的。在海洋生态学中，基础的组成部分是对焦点地点的物种相互作用的分析，这些地点被水流沐浴着，水流运送着营养物质、食物和下一代生物的生殖繁殖体。因此，生活在当地地点的群落在一定程度上通过海洋学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作为智力努力的群落生态学的发展至关重要，对于预测沿海海洋生态系统的当地生物群将如何被日益加快的全球变化所改变也至关重要。后一种情况之所以适用，是因为全球大气过程调节着与局部地点耦合的洋流。虽然扩大海洋研究的空间尺度的必要性已被认识了近二十年，但在发展海洋底栖生物生态学的区域海洋学观点方面进展缓慢，特别是在潮下生态系统方面。本项目通过为加拉帕戈斯海洋保护区（GMR）中生活在岛屿陡峭水下侧面（岩壁）的底栖生物群落开发区域背景来实现这些更广泛的目标（Bustamente et al 2000）。加拉帕戈斯海洋保护区是世界第二大海洋保护区（Bustamente et al 2000）。由于有营养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海底生物的重要性提供了极好的机会。向上（即由食物资源驱动）vs向上？底栖生物群落的向下（掠夺性）调节。项目组的初步研究表明，群落变化的速度特别快，其中水流以迄今为止报道的最高上升流速度（60厘米每秒）涌上岩壁。一个实验设计是用来检验一般假设，即底部？上和上？岩壁群落的向下控制随上升流的变化而变化。在GMR中部8个地点定期测量的上升流、叶绿素a、营养物质和浮游动物浓度，将与查尔斯达尔文研究站新SeaWIFS设施提供的每日高分辨率chl a图像进行比较，置于更大的背景下。测量在不受食草动物影响和暴露于食草动物的处理中藻类的积累，将评估底栖藻类对潜在增强的上涌营养体系的反应。因为epifaunal。以浮游生物为食的无脊椎动物将水柱的生产与更高的营养水平联系起来，提出了实验来测量5种底栖物种及其消费者（蜗牛、海胆）的生长和补充，以检验自下而上和顶部？下行联动。主要捕食者将被围起来，以评估物种相互作用强度在上升流地点最大的假设，而摄像机将提供另一种测量消费者压力的地点变化的方法。最后，理论和观测表明，由于无脊椎动物的快速繁殖和对主要空间占有者的高捕食，上升流地点的多样性和多样性更替最高。通过在群落生态学、海洋学和保护生物学的交叉路口工作，这项研究将增加我们对物种相互作用的生产力和局部变化如何影响海洋保护区物种多样性的理解。该提案的更广泛的优点是，它将直接有助于保护规划，培养博士生，并对本科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.