Consequences of climate change in allopatric speciation and endemism: modeling the biogeography of Dravidogecko

Western Ghats landscape is unique in habitat diversity and endemism, predicted to undergo massive global warming changes. After the Pleistocene, particular micro-climatic conditions prevailed in the Western Ghats, leading to allopatric speciation and endemism. We evaluated this hypothesis by modeling the distribution patterns of endemic ancient reptilian genera, the Dravidogecko using various environmental variables under past, present, and future climate scenarios. We surveyed 58 heterogeneous locations for one year in the Nilgiris (Southern Western Ghats), where the species records are not there. We used environmental variables like diurnal range, isothermality, altitude, precipitation, canopy height, and density to predict the current distribution model. The paleoclimate modeling indicates the presence of species extant throughout the Southern Western Ghats in the Pleistocene. The geographical isolation due to the redress of cooler weather from the lower reaches enclosed the climatic specialist, Dravidogecko, to the upper reaches leading to allopatric speciation. We conclude that climate-oriented speciation is under threat as it may lose all the suitable habitats due to global warming and climate change. We also nominate a new species named Dravidogecko coonoorenis and predict more species of this genus from the Western Ghats.