Relationship between species richness, taxonomic distinctness, functional diversity, and local contribution to β diversity and effects of habitat disturbance in the riparian spider community of the Ganga River, India

Abstract

Abstract Background In the riverine riparian ecosystem, particularly in India, the knowledge of the effects of habitat disturbance on taxonomic distinctness, functional diversity, and local contribution to β diversity (LCBD) of spider community is elusive. The present study examined the relationships between the index of taxonomic distinctness (Δ+), index of variation in taxonomic distinctness (λ+), functional evenness (FEve), functional divergence (FDiv), functional dispersion (FDis), and LCBD of spider community of the Ganga River and the effects of habitat disturbance on these indices. A total of 27 sampling sites were selected along the bank of the Ganga River. Based on the rating of the disturbance scores, the sites were classified into lowly, moderately, and highly disturbed sites. To understand the relationships between species richness, Δ+, λ+, FDis, FDiv, FEve, LCBD, and habitat disturbance score, Pearson’s correlation was calculated, followed by the linear regression model. The one-way multivariate analysis of variance was used to find differences in taxonomic distinctness and functional diversity in the different disturbed sites. Results Significant relationships were found between λ+ and Δ+, FDis and Δ+, FDis and λ+, FDiv and species richness, FEve and species richness, FEve and λ+, FEve and habitat disturbance, LCBD and FEve, and LCBD and habitat disturbance. A significant difference was present in the indices of functional diversity between the lowly, moderately, and highly disturbed sites. Agriculture, garbage dump, human settlement, and created embankment influenced the spider community's λ+, FEve, and LCBD. Conclusion Unrestrained anthropogenic activities exacerbate habitat disturbance by affecting ecological processes. Thus, understanding linkages between ecosystem disturbance, taxonomic, functional, and β diversity can be fundamental to managing and conserving natural resources. This work highlights the importance of including taxonomic and functional diversity to comprehend the impact of habitat disturbance on riverine riparian spiders beyond just the number of species. An integrated taxonomic and functional diversity approach coupled with β diversity can be used to support environmental assessment, restoration, and conservation planning of the biological resources of the Ganges River.