Fenchel Tom
Department of Ecology, University of Aarhus, Århus.
Oecologia. 1975 Mar;20(1):1-17. doi: 10.1007/BF00364318.
The distribution patterns of four species of mud snails (Hydrobiidae) in a complex, estuarine environment are described. The species show habitat selection with respect to salinity but the tolerance ranges of the species overlap and it is shown that this factor alone cannot predict the distribution in the field. The found patterns show that the species are subdivided into many, more or less isolated sub-populations. It is conjectured that the distribution of the species results from the interaction of habitat selection, dispersal rates, colonizations, interspecific competition and extinctions. This interpretation explains features of the distribution patterns; e.g., the boundaries between two species in salinity gradients occur at different salinities in different areas, the species with an intermediate position with respect to salinity preference is the least frequent one, and that coexistence between two, and sometimes three species may occur under certain conditions. The possibility that the species may sustain populations within some areas as "fugitive" species is also discussed.The interpretations are compared with the theory of island biogeography and many parallels are found. The findings are also contrasted to the concept of communities as "natural units".Finally, in an appendix, a simple mathematical model is described. It treats the possibility of coexistence between competing species as a result of migrations between different habitats.
本文描述了四种泥螺（椎实螺科）在复杂河口环境中的分布模式。这些物种表现出对盐度的栖息地选择，但物种的耐受范围存在重叠，并且表明仅这一因素无法预测其在野外的分布。所发现的模式表明，这些物种被细分为许多或多或少孤立的亚种群。据推测，物种的分布是栖息地选择、扩散速率、定殖、种间竞争和灭绝相互作用的结果。这种解释说明了分布模式的特征；例如，盐度梯度中两个物种之间的边界在不同区域出现在不同盐度处，在盐度偏好方面处于中间位置的物种是最不常见的，并且在某些条件下两个物种有时甚至三个物种可能共存。还讨论了这些物种作为“逃亡”物种在某些区域维持种群的可能性。将这些解释与岛屿生物地理学理论进行了比较，发现了许多相似之处。研究结果也与将群落视为“自然单位”的概念形成对比。最后，在附录中描述了一个简单的数学模型。它探讨了由于不同栖息地之间迁移导致竞争物种共存的可能性。
