Finnish Environment Institute, Natural Environment Centre P.O. Box 413, FI-90014, Oulu, Finland ; Department of Biology, University of Oulu P.O. Box 3000, FI-90014, Oulu, Finland.
Ecol Evol. 2014 May;4(10):1931-42. doi: 10.1002/ece3.1076. Epub 2014 Apr 19.
The regional occupancy and local abundance of species are affected by various species traits, but their relative effects are poorly understood. We studied the relationships between species traits and occupancy (i.e., proportion of sites occupied) or abundance (i.e., mean local abundance at occupied sites) of stream invertebrates using small-grained data (i.e., local stream sites) across a large spatial extent (i.e., three drainage basins). We found a significant, yet rather weak, linear relationship between occupancy and abundance. However, occupancy was strongly related to niche position (NP), but it showed a weaker relationship with niche breadth (NB). Abundance was at best weakly related to these explanatory niche-based variables. Biological traits, including feeding modes, habit traits, dispersal modes and body size classes, were generally less important in accounting for variation in occupancy and abundance. Our findings showed that the regional occupancy of stream invertebrate species is mostly related to niche characteristics, in particular, NP. However, the effects of NB on occupancy were affected by the measure itself. We conclude that niche characteristics determine the regional occupancy of species at relatively large spatial extents, suggesting that species distributions are determined by environmental variation among sites.
物种的区域占有率和局域丰度受各种物种特征的影响，但这些相对影响的理解还很有限。我们使用小粒度数据（即多个局部溪流站点）和较大的空间范围（即三个流域）研究了溪流无脊椎动物的物种特征与占有（即占有位点的比例）或丰度（即占有位点的平均局域丰度）之间的关系。我们发现，占有与丰度之间存在显著但较弱的线性关系。然而，占有与生态位位置（NP）密切相关，但与生态位宽度（NB）的关系较弱。丰度与这些基于生态位的解释变量的关系最多只是微弱的。生物特征，包括摄食模式、生活习性、扩散模式和体型类别，在解释占有和丰度变化方面通常不太重要。我们的研究结果表明，溪流无脊椎动物物种的区域占有主要与生态位特征有关，特别是 NP。然而，NB 对占有率的影响受到测量方法本身的影响。我们得出结论，生态位特征决定了物种在相对较大的空间范围内的区域占有，这表明物种的分布是由站点之间的环境变化决定的。
