Species-area relationships of plant communities and the possibility of predicting plant species diversity – a case study in South-Western Poland

2012-06-25T21:14:39Z (GMT) by Krzysztof Świerkosz
<p>The main aim of this study was to consider the possibility of predicting the number of plant species in areas occupied by many different habitat types. A very simple mathematical model was proposed for this purpose. It is based on two fundamental assumptions: first – every single type of community has its own species-area model relationship, second – the number of species common to various types of habitats allometrically depends on the number of habitats and on their quality. <br>In order to test the proposed model, first the species-area relationships for single community types should be counted. Basic data were obtained from phytosociological tables published for SW Poland in 1960–2002. Each set of patches of a plant community, represented in one phytosociological table, was treated as one, compact habitat island of a size comparable to the joint acreage of the patches. The research covered all literature-documented plant communities from SW Poland – in all 750 phytosociological tables including 223 associations and plant communities. <br>The data on 173 syntaxa compiled in 667 tables were used in the analysis – the remaining tables were represented by insufficient numbers of syntaxa (fewer than five), or by insufficient number of phytosociological releves (three or fewer). The species-area relationship models for 57 types of communities were counted this way.<br>The next step involved substituting the results of the single SPAR models in the previously proposed -diversity allometric model. The model was tested on 13 different-sized and 18 equal-sized areas in SW. Poland using GIS tools. In both cases the differences between the actual and predicted number of plant species does not exceed 12%. <br>The consequences of the obtained results were discussed in the light of the main problems implied in the issue of species-area relationship.</p>