Role of anthropogenic transformation and environmental gradients in tree composition, stand structure and biomass carbon stock in Chinnar Wildlife Sanctuary of Western Ghats, India

This study assessed the tree species composition, stand structure, biomass, and carbon stocks across an anthropogenic transformation gradient comprising undisturbed (UD), mildly disturbed (MD), and highly disturbed (HD) zones in Chinnar Wildlife Sanctuary, Western Ghats, India, through the inventory of 30 plots (0.1 ha each). Species richness declined significantly with increasing anthropogenic transformation, and clear shifts in community composition were observed. HD sites were characterised by higher stem density and greater representation of disturbance-tolerant and plantation-associated species, particularly Eucalyptus grandis, whereas UD sites supported structurally complex stands with larger trees and greater basal area (BA). Although BA, biomass, and carbon stocks showed declining trends with increasing anthropogenic transformation, these differences were not statistically significant. Generalised linear models identified BA as the strongest predictor of total carbon stock, while elevation showed no significant independent effect after accounting for multicollinearity among climatic variables. Redundancy analysis indicated that species composition was associated with anthropogenic transformation history, stand structure, and environmental gradients, particularly elevation and precipitation. Overall, the strongest patterns were observed in species richness and community composition, whereas carbon storage was more closely associated with stand structural attributes, especially BA, than with anthropogenic transformation intensity alone.