How Important are Regional Processes in Determining the Local Species Diversity of Marine Communities

本研究调查了11个生物地理区域(至少33个地点)生物地理区域(空间尺度为10‘~1W Kms)中的物种数量与当地群落(空间尺度为1~10’m)中固着的附生无脊椎动物数量之间的关系。需要检验的主要预测是：如果当地社区仅仅是生物地理(区域)物种池中的一个水槽，那么当地物种丰富度将与广泛多样性的区域物种丰富度成正比和线性关系。或者，如果生态相互作用限制了共存于当地栖息地的物种数量，那么当地丰富度对区域丰富度的回归将持平或饱和。我们建议用定量摄影技术对不同生物地理区的附生动物群落的物种丰富度进行采样，以检验这些假说。当地的多样性将从35 mm的照片样本(0.25米)，沿着横跨潮汐下岩壁水平放置在大约10米深的横断面上的随机位置进行量化。样本照片将被分析，直到每个位置的物种累积数量的曲线图渐近线，这将构成我们对当地物种丰富度的衡量。区域物种丰富度将从公布的物种名单中估计，并通过咨询每个地点的当地专家来估计。这里开发了回归技术来检验区域影响相对于局部饱和度的预测。此外，还将探讨4个相关问题，以加深我们对以下问题的理解：1)个体(或群体)大小与当地物种丰富度的关系；2)幼虫扩散模式解释区域影响程度与当地物种丰富度的能力；3)物种密度、当地物种丰富度与区域物种丰富度之间的关系；4)不同类群之间当地和地区物种丰富度关系的性质如何变化。保护生物多样性是当前和下个世纪最紧迫的环境问题之一。准确确定对地球生物多样性的威胁的性质，并设计和实施合理的保护战略，需要了解影响生物多样性时空格局的因素。拟议的研究结果将极大地提高我们批判性地评估区域进程在构建浅海硬基岩群落方面的重要性的能力。

This study investigates the relationship between the number of species in biogeographic regions (spatial scale of 10' to 1W kms ) and the number occurring in local communities (spatial scale of 1 to 10'm's) of sessile epifaunal invertebrates from 11 biogeographic regions comprising at least 33 local sites. The main predictions to be tested are: if local communities are simply a sink from the biogeographic (regional) species pool, then local species richness will be positively and linearly related to regional species richness over a broad range of diversities. Alternatively, if ecological interactions limit the number of species coexisting in local habitats, then regressions of local richness on regional richness will level off or saturate. We propose to test these hypotheses by sampling the species richness of epifaunal communities in different biogeographic regions with quantitative photographic techniques. Local diversity will be quantified from 35 mm photo quadrats (0.25m ) taken at random locations along transects placed horizontally across subtidal rock walls at approximately 10 m depth. Quadrat photos will be analyzed until a plot of the cumulative number of species at each location asymptotes, which will comprise our measure of local species richness. Regional species richness will be estimated from published species lists and by consulting local experts at each site. Regression techniques are developed herein to test the predictions of regional influence vs. local saturation. In addition, four related questions will be investigated to increase our understanding of 1) the relationship between body (or colony) size and local species richness 2) the ability of larval dispersal mode to explain the degree of regional influence an local richness, 3) the relation between species density, local species richness and regional species richness and 4) how the nature of the relationship between local and regional richness varies among different taxa. The preservation of biological diversity is one of the most pressing environmental issues of the present and next century. Accurately identifying the nature of threats to Earth's biotic diversity and designing and implementing sound conservation strategies requires an understanding of the forces that shape spatio temporal patterns of biodiversity. The results of the proposed research will greatly enhance our ability to critically assess the importance of regional processes in structuring shallow marine hard substrate communities.