Historical and recent fragmentation of temperate floodplain grasslands: Do patch size and distance affect the richness of characteristic wet meadow plant species?

摘要: Patch size and isolation are thought to have a large influence on the extinction risk of specialist plant species in grassland fragments modern agricultural landscape. We combined re-sampling study semi-permanent floodplain plots with GIS-based analysis historical (1950s/1960s) recent landscape patterns. Based vegetation maps releves from six areas (plus protected reference area) covering 50–60 years change following intensification, we aimed at analysing importance fragmentation diversity potentially sensitive wet meadows northern Germany. On plot scale, found 30–66 % reductions richness these characteristic meadow over time an associated increase habitats. Distance nearest suitable habitat had modest negative effect plot-scale richness, while other tested metrics (total area, mean patch proximity index distribution) no significant influence. There was also evidence for legacy structure current species. Instead, management intensity its past decades, as indicated by altered Ellenberg indicator values nutrients moisture, strong diversity. The results suggest that is not proximate cause impoverishment point deterioration main driver. conclude conservation measures Central-European should only focus continuous areas, but consider small patches if they remained species-rich.