Local and species contribution of beta diversity of macrophytes in perspective of conservation and restoration of Ganga River, India

The biodiversity of freshwater ecosystems especially macrophytes are threatened by various anthropogenic factors. We performed this study to investigate the beta diversity pattern of macrophyte communities in the Ganga River to find out their relationship with the physio-chemical properties of the habitat and to identify their life forms with conservation priorities and ensuring priority areas for conservation and restoration. We found that the species replacement (Repl) contributes more to beta diversity than similarity (S) and richness difference (RichDiff) component indicating continuous macrophyte turnover along the Ganga river. We found that the local contribution to beta diversity (LCBD) has a significant positive relationship with organic carbon and nitrate. We identified seven sites in the middle and lower reach of the Ganga River whose LCBD values lie within the top 75% indicating that these sites have unique species composition. The species with the highest species contribution to beta diversity (SCBD) values were mostly emergent macrophytes, which have a greater influence on the beta diversity in the studied region. Thus, when developing models and action plans for Ganga River management, which includes both biodiversity conservation and restoration, the middle and lower sections of the river, as well as emergent macrophytes, should be considered.