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（至少包含33个局地点）的无底无脊椎动物物种数量（空间尺度为10′~ 1 w km）与局地群落（空间尺度为1′~ 10 m’s）之间的关系。待验证的主要预测是：如果本地群落只是生物地理（区域）物种库中的一个汇，那么在广泛的多样性范围内，本地物种丰富度将与区域物种丰富度呈正线性关系。或者，如果生态相互作用限制了在当地栖息地共存的物种数量，那么当地丰富度对区域丰富度的回归将趋于平稳或饱和。我们建议通过采用定量摄影技术对不同生物地理区域的地表层群落的物种丰富度进行采样来验证这些假设。局部多样性将通过35毫米照片样方（0.25米）进行量化，这些样方沿着横向放置在约10米深的潮下岩壁上的横断面随机地点拍摄。将对样方照片进行分析，直到绘制出每个地点渐近线处的物种累积数量图，这将构成我们对当地物种丰富度的测量。区域物种丰富度将根据公布的物种清单和咨询每个站点的当地专家来估计。本文开发了回归技术来测试区域影响与局部饱和度的预测。此外，还将研究四个相关问题，以增加我们对以下问题的理解：1)体（或群体）大小与局部物种丰富度之间的关系；2)幼虫扩散模式解释局部物种丰富度区域影响程度的能力；3)物种密度、局部物种丰富度和区域物种丰富度之间的关系；4)不同分类群之间局部和区域物种丰富度之间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。准确地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，需要了解形成生物多样性时空格局的力量。拟议的研究结果将大大提高我们批判性地评估区域过程在构建浅海硬基质群落中的重要性的能力。

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.