Predicting Potential Habitats of Nilgiri Tahr (Nilgiritragus hylocrius) in Periyar Tiger Reserve under Current Landscape Conditions Using MSTrIPES and GIS
Abstract
The Nilgiri Tahr (Nilgiritragus hylocrius), an endangered mountain ungulate endemic to the Western Ghats of India, is a flagship species of the montane ecosystems, yet its habitat preferences and spatial ecology remain insufficiently explored. This study employed Species Distribution Modelling (SDM) using the Maximum Entropy (MaxEnt) algorithm integrated with Geographic Information System (GIS) to predict the potential distribution of Nilgiri Tahr in the Periyar Tiger Reserve (PTR), Kerala. Presence data were obtained from MSTrIPES field surveys (April 2024 to September 2025) and correlated with 24 environmental variables, including elevation, slope, aspect, NDVI, rainfall, temperature, land cover, and distance to water sources. Model performance was evaluated using the Area Under the Receiver Operating Characteristic Curve (training AUC = 0.923, test AUC = 0.922) and jackknife tests to determine the relative contribution of predictor variables. Habitat suitability was classified into three probability categories: Unsuitable, moderately Suitable and Highly Suitable. The model revealed that highly suitable habitats covered approximately 134.97 km², moderately suitable habitats spanned 249.52 km², and unsuitable areas accounted for 540.51 km². The most suitable habitats were concentrated along Ponnambalamedu, Mangaladevi, Palkachimala, Medhakanam, Pachamudi, Kumarikulam, Vaikolpadappu, and Manamuttymala, extending towards Circle Road, Uppupara, Zero Point, Venkalapara, Ottamaram, and Churulipara. These zones are characterized by steep grassland-Shola mosaics and rugged high elevation cliffs, providing ideal foraging, resting, and breeding environments for the species. Conservation management should emphasize the maintenance of high-altitude grassland connectivity, protection of Shola grassland ecotones, and integration of Nilgiri Tahr habitats into PTR’s conservation and monitoring framework to ensure long-term population persistence under changing climatic conditions.