Lokale Muster Pflanzlicher Artenvielfalt

Abstract

SummaryPlant species diversity varies in different plant communities over a wide range of spatial scales. In this study the local variation of species richness along gradients of productivity, environmental factors, environmental heterogeneity and disturbance were analysed in different plant communities. The documented patterns were compared to theoretical models and relationships as observed in previous studies. Multiple models to predict plant diversity were developed. The vegetation data was assessed in grassland and decideous forests of Northern Germany using a standardised method. For all study sites productivity level, chemical soil properties, relative light availability in forests, environmental heterogeneity and management intensity in grassland were determined. Furthermore, several studies in forests, grassland, sand meadows and mires were compiled and reviewed on their relationship of pH and species richness. For statistical analysis mainly univariate and multiple regressions were appliedThe following results were documented: 1) Plant diversity peaks corresponded to forests, grassland, mires and sand meadows with intermediate pH. 2) A unimodal model described best the relationship between species richness and productivity in deciduous forests with a large productivity gradient at different scales, while negative linear correlations were predominant in grassland communities. 3) Generally, multiple models explained more of the variation in species richness than univariate models. 4) Models comprising productivity, pH, heterogeneity in light intensity, C/N ratio, soil Calcium content as well as on smaller plots average light availability resulted in the highest predictive abilities for species numbers in forests. 5) In grassland communities the effect of current meadow use and management history in determining species richness dominated, whereas productivity and chemical soil properties had only a weak relationship with plant diversity. 6) Plant diversity increased with heterogeneity in light availability in forests, while intermediate heterogeneity in pH maintained highest species numbers. 7) Peaks of heterogeneity in light availability corresponded to moderately productive deciduous forests. 8) The patterns of plant diversity were scale-dependent with different factors dominating at varying scales.