Testing scale variance in species–area and abundance–area relationships in a local assemblage: an example from a subtropical boulder shore
Testing scale variance in species–area and abundance–area relationships in a local assemblage: an example from a subtropical boulder shore
复制标题
测试局部组合中物种-面积和丰度-面积关系的尺度变化：来自亚热带巨石海岸的示例
作者：
E. Londoño;M. Tokeshi
物种-面积关系和丰度-面积关系的恒常性或尺度变异很少在局部组合的相对较小的空间域内被考虑。实验研究了亚热带巨石海岸石栖软体动物群落的物种/丰度-面积关系模式。为了系统地研究栖息地面积变化的影响，同时保持其他栖息地特征随时间的变化不变，选择天然形成的石头，并根据表面积将其划分为不同的大小类别，并将其作为移动软体动物群落的栖息地单位进行定期监测。软体动物的物种丰富度和丰度（个体数和生物量）以石面积为尺度，但幂或双对数回归并不总是物种-面积关系的最佳描述。物种-面积关系表现出季节尺度不变性，而丰度-面积关系表现出明显的尺度变异。后一种现象主要是由于巨大的石头不成比例地增加了软体动物的丰度。此外，栖息地面积小对小石头上软体动物的丰度不成比例地减少也有负面影响。观察到的模式也有一定的时间变化，春季的物种丰富度和丰度高于冬季，同样以较大的石头显示出优势。因此，该研究表明，即使在相对较小的局部栖息地空间尺度内，物种/丰度-面积关系的尺度变异/不变性也具有重要意义。
Constancy or scale variance of species–area and abundance–area relationships has rarely been considered within relatively small spatial domains of a local assemblage. Patterns of species/abundance–area relationships were experimentally investigated in a stone-associated molluscan community on a subtropical boulder shore. In order to systematically examine the effects of variation in habitat area while maintaining other habitat characteristics constant through time, naturally occurring stones were selected and divided into different size classes according to surface area and used as habitat units for regular monitoring of a mobile molluscan community. Species richness and abundance (number of individuals and biomass) of molluscs scaled with stone area, but the power or double-logarithmic regression was not always the best description of the species–area relationship. Seasonal scale invariance was shown by the species–area relationship, whereas scale variance was clearly recognizable in the abundance–area relationships. The latter phenomenon was generated mainly by large stones contributing disproportionately to increases in molluscan abundance in particular. Furthermore, there was a negative effect of small habitat area whereby molluscan abundance was disproportionately reduced on small stones. Some temporal variation in the observed patterns was also recognizable, with higher species richness and abundance in spring than in winter, again with larger stones showing preponderant importance. This study thus demonstrates the significance of scale variance/invariance in species/abundance–area relationships, even within relatively small spatial scales of local habitat.