Environmental predictors of distribution of herbaceous endemic species from lateritic rock outcrops of the Western Ghats and Konkan region, India

Endemism serves as an ecological metric and indicator, informing conservation planning worldwide. Within this context, the Western Ghats emerge as a pivotal biogeographical region, particularly renowned for its rich array of endemic species. Among the various habitats within this region, rock outcrops stand out as a critical habitat for herbaceous endemic species as they support higher endemism as compared to other habitats. Despite their ecological significance, a comprehensive understanding of the environmental factors shaping herbaceous endemic diversity within these habitats remains elusive. Understanding the effect of environmental parameters can give insights into how species would deal with current and future climate. In the present study, we studied the relationship between the distribution of herbaceous endemic species and environmental parameters. In addition to that we also investigated which microhabitats on rock outcrops support maximum endemic species. The study was conducted on 15 lateritic rock outcrops (LRO) in the Goa and Konkan regions of Maharashtra. We recorded a total of 100 herbaceous endemic taxa spanning 25 families and 48 genera. Based on Principal Component Analysis (PCA) the sites were grouped into three groups: high-elevation LROs, low-elevation Konkan LROs and low-elevation Goa LROs. NMDS revealed that this grouping is based on the elevation, annual mean temperature and isothermality. Among the various microhabitats on LROs, shallow soil covered areas emerged as pivotal microhabitats for endemic species richness followed by ephemeral flush vegetation and exposed rock surfaces. This study highlights the intricate relationship between environmental factors, microhabitat characteristics, and herbaceous endemic diversity in the Western Ghats, emphasizing that region focused studies provide crucial insights for conservation efforts.