Department of Biological Sciences, Florida International University, North Miami, FL, USA.
Oecologia. 2011 Sep;167(1):157-68. doi: 10.1007/s00442-011-1959-3. Epub 2011 Mar 16.
Habitat variability at multiple spatial scales may affect community structure within a given habitat patch, even within seemingly homogenous landscapes. In this context, we tested the importance of habitat variables at two spatial scales (patch and landscape) in driving fish community assembly using experimental artificial reefs constructed across a gradient of seagrass cover in a coastal bay of The Bahamas. We found that species richness and benthic fish abundance increased over time, but eventually reached an asymptote. The correlation between habitat variables and community structure strengthened over time, suggesting deterministic processes were detectable in community assembly. Abundance of benthic fishes, as well as overall community structure, were predicted by both patch- and landscape-scale variables, with the cover of seagrass at the landscape-scale emerging as the most important explanatory variable. Results of this study indicate that landscape features can drive differences in community assembly even within a general habitat type (i.e., within seagrass beds). A primary implication of this finding is that human activities driving changes in seagrass cover may cause significant shifts in faunal community structure well before complete losses of seagrass habitat.
在多个空间尺度上的生境变异性可能会影响给定生境斑块内的群落结构，即使在看似同质的景观中也是如此。在这种情况下，我们使用在巴哈马沿海湾的海草草甸覆盖梯度上建造的实验性人工礁石，测试了两个空间尺度（斑块和景观）上的生境变量对鱼类群落组装的重要性。我们发现，物种丰富度和底栖鱼类丰度随时间增加，但最终达到一个渐近线。生境变量与群落结构之间的相关性随时间增强，表明在群落组装中可以检测到确定性过程。底栖鱼类的丰度以及整体群落结构都可以通过斑块和景观尺度的变量来预测，而景观尺度上的海草覆盖率则成为最重要的解释变量。本研究的结果表明，即使在一般的生境类型（即海草床内）中，景观特征也可以驱动群落组装的差异。这一发现的主要意义是，导致海草覆盖率变化的人类活动可能会在海草生境完全丧失之前，导致动物群落结构发生重大变化。
