Local and species contribution to the beta diversity and rarity of riparian spider community of the Ganga River, India

A modern approach to understanding biodiversity variation is to deconstruct beta diversity patterns into the local contribution to beta diversity (LCBD-uniqueness in species composition of a site) and species contribution to beta diversity (SCBD-influence of a species in the beta diversity within the region) which is a good approach to improving knowledge of the beta diversity. We carried out this work to understand the pattern and relationship of LCBD, SCBD and the rarity of the spider community in the riparian habitat of the Ganga River. We calculated the correlation between LCBD and species richness of both all the species and rare species. We used the first order and second order terms to find the relationship between SCBD and the number of sites occupied by species and to find the relationship between SCBD and the index of rarity for all the species and three ecological guilds of spiders. We found that the LCBD of the spider community had a significant relationship with total species richness but not with rare species richness. Spider species with intermediate occurrence across the study sites contributed more to SCBD values than species with high and low occurrence. We found that the index of rarity of spider species had a significant relationship with SCBD values. The non-parametric permutational multivariate analysis of variance (PERMANOVA) tests revealed no significant differences in the distribution of different ecological guilds of spiders between the study sites. The integrated LCBD and SCBD approach can be used to carry out effective conservation and restoration programmes that preserve the structural, functional, and ecological diversity of spiders, as well as other biological communities in riparian ecosystems.