Different components of plant diversity suggest the protection of a large area for the conservation of a riparian ecosystem

Abstract

AbstractRiparian ecosystems host an high level of biodiversity but anthropic activities have deeply altered their naturalness and functionality. The present study was carried out in a protected area along a recently regulated tract of the upper River Tiber (Tuscany, central Italy). The study’s aim is to explore different components of plant diversity (species richness, species composition, β-diversity) in the riparian habitats to determine the most relevant conservation issues. Twelve transects were allocated along the riparian zone and a stratified random sampling was performed on the habitat detected along the transects with 184 plots of 1 x 1 m. Species richness was analysed by the use of set of species-richness estimators. The different patterns of plant diversity were analysed by NMDS, Indicator Species Analysis and SDR with symplex analysis. Five habitat types were detected in the study area. Three well-represented habitats (riparian woodlands, shrublands and dry bars) showed a higher number of species; flooded banks and marshlands were much less common and were also less species rich. Species composition and indicator species analysis showed however that marshlands were the richest in taxa having high conservation value and in indicator species. The habitats differed greatly in species composition; β-diversity analysis showed a low number of shared species between the habitats. High values of species replacement and low similarity values were recorded between the plots within the habitats. The study shows some differences between quantitative and qualitative patterns of biodiversity in the study area. The results suggest that to maintain habitat species diversity, the best conservation strategy for the study area is to protect as large an area as possible