Complementarity of species assemblages between communities retains high species richness in a region consisting of these communities. If intertidal zones have the complementarity against subtidalzones, which is mainly consisted in port area, we can increase the species richness in port areas by restoring intertidal zones. In this study I focused on species richness, the number of taxonomic groups, and developed a method for fi nding a community that have complementarity of species assemblages against other community. In addition, I analysed the data of benthic marine animals obtained in Matsunaga Bay to test whether intrtidal zones have the complementarity against subtidal zones or not.
Numbers of taxonomic groups shared between two communities and taxonomic groups occurring in a community but not in another community are important parameters for assessing complementarity of species assemblages. However, because the number of observed taxonomic groups depends on sampling effort, we cannot compare these numbers without understanding the response of these numbers to sampling effort. In this study I proposed a method for finding these numbers. First, we confirm the validity to compare communities at same or similar sampling effort by checking the response curves of number of taxonomic groups against sampling effort, rarefaction curves, in the communities. Second, the expected numbers of taxonomic groups shared between two communities and taxonomic groups occurring in a community are extracted by using a Monte Carlo technique. The method could work for data obtained in a natural fi eld. As the fi rst application of the developed method, the complementarity of speces assemblages between these zones was found by using the data sets that have been obtained in a subtidal zone and an intertidal zone, in Matsunaga Bay, by past projects. This finding means that restoring intertidal zones in ports can contribute to increase biodiversity; that is, to increasing biodiversity initiative proposed in the national biodiversity strategy in Japan.
Key words:Species richness, Complementarity of species assemblages, Number of observed species,Rarefaction curve, Benthic marine animals, Effective use of data