MaxEnt modeling for habitat suitability assessment of threatened Dipterocarpus species in the Indian East Himalayas

The Dipterocarpus forests of the Indian East Himalayas are essential for biodiversity conservation, ecosystem health, and carbon sink management. However, anthropogenic activities and global climate change have posed significant threats to Dipterocarpus species. This study aimed to assess habitat suitability and identify key environmental variables for one endangered species (Dipterocarpus retusus), two vulnerable species (Dipterocarpus gracilis and Dipterocarpus turbinatus), and one near-threatened species (Dipterocarpus tuberculatus). We used MaxEnt model to assess the current and future projected distribution under three climate change scenarios: SSP1-2.6 (low), SSP2-4.5 (moderate), and SSP5-8.5 (high) by 2050 and 2070. Out of the total study area of 268.97 (‘000 km²), 1.62 (‘000 km²) is currently highly suitable for D. gracilis, with projections showing an increase of 6.00–25.51% by 2070. For D. retusus, 15.90 (‘000 km²) is highly suitable under the current climate scenario, but this is projected to decrease by 2.94–5.86% by 2070. Conversely, the highly suitable area for D. retusus is expected to increase by 1.27% under SSP2-4.5 by 2050. Similarly, 1.95 (‘000 km²) is highly suitable for D. tuberculatus now, with an expected increase of up to 17.58% under SSP2-4.5 by 2050. For D. turbinatus currently has 5.82 (‘000 km²) of highly suitable area, projected to increase by 9.11–14.07% by 2050 and 15.96–19.06% by 2070. Key factors influencing Dipterocarpus habitats include anthropogenic land-use changes, forest types, soil water-holding capacity, temperature, and precipitation regimes. Our habitat suitability output can provide baseline information on current and future habitat suitability of studied Dipterocarpus species, which will be helpful to guide formulation of effective forest management policies that are vital for species conservation and forest management in India.