Between a rock and a hard place: Effects of land-use change on rock-dwelling animals of lateritic plateaus in the northern Western Ghats

Abstract

Open natural ecosystems like lateritic plateaus, are undergoing rapid transformation with very poor understanding of these impacts on the threatened and endemic biodiversity. The unprotected, low-elevation lateritic plateaus of the northern Western Ghats are case to the point, as they have high endemicity but remain unprotected under Indian law. We aimed to understand the impact of the conversion of the natural lateritic plateaus to agroforestry and paddy cultivation on biodiversity. We compared the prevalence of two species of endemic herpetofauna of the northern Western Ghats (Gegeneophis seschachari and Hemidactylus albofasciatus) and a widespread snake (Echis carinatus) and the composition of other rock-dwelling animals across 12 undisturbed plateau sites and 10 sites each in agroforestry plantations and abandoned paddies on plateaus using time-constrained searches. We had 5738 encounters with 38 different animal species/groups. We found that the abundance of large rocks, which were the most-preferred size class of rocks by animals, was higher in abandoned paddy compared to plateaus and orchards. However, the prevalence of H. albofasciatus and E. carinatus was highest on undisturbed plateaus. Contrastingly, the prevalence of G. seshachari was significantly higher in abandoned paddy than undisturbed plateau or orchards. Non-metric multi-dimensional analysis showed that the assemblage of rock-dwelling fauna differed significantly across the three land-use types. Despite being adapted to persist in extremely variable climates on lateritic plateaus, we find that multiple species/groups are vulnerable to land-use change. However, G. seshachari and a few other taxa appear to benefit from certain kinds of land-use change, highlighting the context-specificity in species responses. While multiple studies have determined the impacts of forest conversion to other land-uses, this is one of the first studies to determine the impacts of the conversion of rocky outcrops, thereby highlighting the conservation value of habitats that are often classified as wastelands.