Bethke Raymond W
Department of Zoology, University of Guelph, N1G 2W1, Guelph, Ontario, Canada.
Oecologia. 1993 Feb;93(1):102-108. doi: 10.1007/BF00321198.
Geographical gradients of persistence in community structure have been suggested to be causally related to underlying gradients of species diversity, environmental variability and/or productivity. In order to test whether the persistence of breeding duck communities was dependent on any one of these three factors, thirty-three years of census data from the Canadian prairie and boreal forest regions was examined along geographical gradients of wetland habitat variability and productivity. For breeding ducks, locally derived patterns of persistence were generally independent of local habitat conditions. Persistence appeared to be related more to patterns of emigration and immigration in response to climatic conditions (i.e., drought) in the southern prairies than to local species richness, wetland habitat variability or productivity. It is suggested, therefore, that analyses of community persistence derived at small spatial scales may be of limited value if the structure of communities is not regulated by local conditions.
群落结构持久性的地理梯度被认为与物种多样性、环境变异性和/或生产力的潜在梯度存在因果关系。为了测试繁殖鸭群落的持久性是否依赖于这三个因素中的任何一个，我们沿着湿地栖息地变异性和生产力的地理梯度，研究了加拿大草原和北方森林地区33年的普查数据。对于繁殖鸭来说，本地的持久性模式通常与当地栖息地条件无关。持久性似乎更多地与南部草原地区对气候条件（即干旱）作出反应的迁离和迁入模式有关，而不是与当地物种丰富度、湿地栖息地变异性或生产力有关。因此，有人提出，如果群落结构不受当地条件的调节，那么在小空间尺度上进行的群落持久性分析可能价值有限。
