Anderson M J
Centre for Research on Ecological Impacts of Coastal Cities and School of Biological Sciences, Marine Ecology Laboratories, A11, University of Sydney, Sydney, NSW 2006, Australia e-mail:
Oecologia. 1999 Jan;118(1):87-98. doi: 10.1007/s004420050706.
The effects of patch size on the colonisation and succession of intertidal invertebrates and algae were investigated in an estuary near Sydney, New South Wales, Australia. The specific aim was to test explicitly for the presence of a species-area relationship, and examine whether this could be explained by the random placement hypothesis (i.e. that the number of species per unit area was the same on patches of different sizes). In addition, I tested the extent to which differences in numbers of species reflected differences in the composition of assemblages. Wooden panels of three different sizes (10 x 10 cm, 20 x 20 cm and 40 x 40 cm) were placed in the field on intertidal oyster leases in each of two different experimental trials: spring (October 1994) and summer (January 1995). Independent replicate measures of the number of colonising species on panels were obtained after different periods of time, up to 25 months. I also obtained measures of abundance of individual species and composition of assemblages on panels of different sizes. This allowed specific tests of the hypothesis that the size of the patch being colonised is important in structuring these assemblages. The strength of the species-area relationship increased through time on panels submersed in October, but the trend was reversed for panels submersed in January. There was a significant interaction between factors of patch size and time of submersion for multivariate measures of differences in composition among replicates. The random placement hypothesis was supported in certain situations, but not in others. When rejected, it was for different reasons on panels submersed in the two different trials. Panels initiated in October tended to have proportionally greater numbers of species per unit area on larger panels, while the panels initiated in January tended to have more species per unit area on smaller panels. There was an identifiable relationship between differences in numbers of species and differences in species composition for panels submersed in October. This was not true, however, for panels submersed in January, where the species-area relationship did not hold after longer periods. The succession of organisms through time was, overall, more important in structuring the assemblages than was the size of the patch being colonised. The species-area relationship should not necessarily be regarded as a truism - it did not always hold in this system. The initial timing of experiments with respect to recruitment and succession influenced the results.
在澳大利亚新南威尔士州悉尼附近的一个河口，研究了斑块大小对潮间带无脊椎动物和藻类定殖及演替的影响。具体目标是明确检验物种 - 面积关系的存在，并考察这是否可以用随机放置假说（即不同大小斑块上单位面积的物种数量相同）来解释。此外，我还测试了物种数量差异在多大程度上反映了群落组成的差异。在两个不同的实验时段（春季，1994年10月；夏季，1995年1月），将三种不同大小（10×10厘米、20×20厘米和40×40厘米）的木板放置在潮间带牡蛎养殖区的野外。在长达25个月的不同时间段后，获得了木板上定殖物种数量的独立重复测量值。我还获得了不同大小木板上单个物种的丰度和群落组成的测量值。这使得能够对被定殖斑块的大小在构建这些群落中很重要这一假说进行具体检验。对于10月浸入的木板，物种 - 面积关系的强度随时间增加，但对于1月浸入的木板，趋势则相反。对于重复样本间组成差异的多变量测量，斑块大小和浸入时间因素之间存在显著的相互作用。随机放置假说在某些情况下得到支持，但在其他情况下则不然。当被拒绝时，在两个不同实验时段浸入的木板上原因不同。10月开始放置的木板往往在较大木板上单位面积的物种数量比例更大，而1月开始放置的木板往往在较小木板上单位面积的物种更多。对于10月浸入的木板，物种数量差异和物种组成差异之间存在可识别的关系。然而，对于1月浸入的木板并非如此，在较长时间后物种 - 面积关系并不成立。总体而言，生物随时间的演替在构建群落方面比被定殖斑块的大小更重要。物种 - 面积关系不一定应被视为一个不言而喻的事实——它在这个系统中并不总是成立。实验相对于补充和演替的初始时间影响了结果。
