Kadmon Ronen, Allouche Omri
Department of Evolution, Systematics and Ecology, Institute of Life Sciences, Hebrew University of Jerusalem, Givat-Ram, Jerusalem 91904, Israel.
Am Nat. 2007 Sep;170(3):443-54. doi: 10.1086/519853. Epub 2007 Jul 16.
We present an analytical model that unifies two of the most influential theories in community ecology, namely, island biogeography and niche theory. Our model captures the main elements of both theories by incorporating the combined effects of area, isolation, stochastic colonization and extinction processes, habitat heterogeneity, and niche partitioning in a unified, demographically based framework. While classical niche theory predicts a positive relationship between species richness and habitat heterogeneity, our unified model demonstrates that area limitation and dispersal limitation (the main elements of island biogeography) may create unimodal and even negative relationships between species richness and habitat heterogeneity. We attribute this finding to the fact that increasing heterogeneity increases the potential number of species that may exist in a given area (as predicted by niche theory) but simultaneously reduces the amount of suitable area available for each species and, thus, increases the likelihood of stochastic extinction. Area limitation, dispersal limitation, and low reproduction rates intensify the latter effect by increasing the likelihood of stochastic extinction. These analytical results demonstrate that the integration of island biogeography and niche theory provides new insights about the mechanisms that regulate the diversity of ecological communities and generates unexpected predictions that could not be attained from any single theory.
我们提出了一个分析模型，该模型统一了群落生态学中两个最具影响力的理论，即岛屿生物地理学和生态位理论。我们的模型通过在一个统一的、基于种群统计学的框架中纳入面积、隔离、随机定殖和灭绝过程、栖息地异质性以及生态位划分的综合影响，捕捉了这两个理论的主要要素。虽然经典生态位理论预测物种丰富度与栖息地异质性之间存在正相关关系，但我们的统一模型表明，面积限制和扩散限制（岛屿生物地理学的主要要素）可能会在物种丰富度与栖息地异质性之间产生单峰甚至负相关关系。我们将这一发现归因于以下事实：异质性增加会增加给定区域内可能存在的物种潜在数量（如生态位理论所预测），但同时会减少每个物种可利用的适宜面积，从而增加随机灭绝的可能性。面积限制、扩散限制和低繁殖率通过增加随机灭绝的可能性强化了后一种效应。这些分析结果表明，岛屿生物地理学和生态位理论的整合为调节生态群落多样性的机制提供了新的见解，并产生了任何单一理论都无法获得的意外预测。
