Belmaker Jonathan, Ziv Yaron, Shashar Nadav, Connolly Sean R
The Department of Life-Sciences, Ben-Gurion University of the Negev, Beer-Sheva 84105, Israel.
Ecology. 2008 Oct;89(10):2829-40. doi: 10.1890/07-1464.1.
The size of the regional species pool may influence local patterns of diversity. However, it is unclear whether certain spatial scales are less sensitive to regional influences than others. Additive partitioning was used to separate coral-dwelling fish diversity to its alpha and beta components, at multiple scales, in several regions across the Indo-Pacific. We then examined how the relative contribution of these components changes with increased regional diversity. By employing specific random-placement null models, we overcome methodological problems with local-regional regressions. We show that, although alpha and beta diversities within each region are consistently different from random-placement null models, the increase in beta diversities among regions was similar to that predicted once heterogeneity in coral habitat was accounted for. In contrast, alpha diversity within single coral heads was limited and increased less than predicted by the null models. This was correlated with increased intraspecific aggregation in more diverse regions and is consistent with ecological limitations on the number of coexisting species at the local scale. These results suggest that, apart from very small spatial scales, variation in the partitioning of fish diversity along regional species richness gradients is driven overwhelmingly by the corresponding gradients in coral assemblage structure.
区域物种库的大小可能会影响当地的多样性模式。然而，尚不清楚某些空间尺度是否比其他尺度对区域影响的敏感度更低。我们采用加法划分法，在印度-太平洋地区的多个区域、多个尺度上，将栖息于珊瑚礁的鱼类多样性划分为其α和β组分。然后，我们研究了这些组分的相对贡献如何随着区域多样性的增加而变化。通过使用特定的随机放置零模型，我们克服了局部-区域回归的方法问题。我们发现，虽然每个区域内的α和β多样性始终与随机放置零模型不同，但考虑到珊瑚栖息地的异质性后，区域间β多样性的增加与预测结果相似。相比之下，单个珊瑚礁内的α多样性有限，且增加幅度小于零模型的预测。这与物种在多样性更高的区域内种内聚集增加有关，并且与局部尺度上共存物种数量的生态限制相一致。这些结果表明，除了非常小的空间尺度外，鱼类多样性划分沿区域物种丰富度梯度的变化主要由珊瑚组合结构的相应梯度驱动。
