Predicting habitat refugia of the medicinal plant Dolomiaea costus under two climate change scenarios

Assessing the impacts of climate change on the distribution of medicinally important and endangered species is critical for conservation planning. This study focuses on Dolomiaea costus (Falc.) Kasana & A.K. Pandey, a critically endangered and highly valuable medicinal plant found in the fragile climate of Pakistan. Using species distribution modelling (MaxEnt), we evaluated the current and future habitat suitability of D. costus under two climate change scenarios (SSP370 and SSP585) for the periods 2041-2070 and 2071-2100. Occurrence data were collected from field surveys and the Global Biodiversity Information Facility (GBIF), while bioclimatic data were sourced from Climatologies at High Resolution for the Earth's Land Surface Areas (CHELSA). The MaxEnt model achieved a high mean AUC value of 0.967, indicating strong predictive accuracy. Suitable habitats for D. costus span approximately 99,871 Km2 across the western Himalayas, Karakoram, and Hindukush regions. Climate projections revealed that under SSP370, suitable areas decrease from 99,260 Km2 in 2041-2070 to 90,962.5 Km2 in 2071-2100, with high-suitability zones reducing from 13,024.5 Km2 to 11,490.5 Km2. In contrast, the SSP585 scenario showed a modest expansion of suitable habitat from 107,104 Km2 to 111,217.5 Km2, though high-suitability areas declined from 18,208 Km2 to 16,811 Km2. Precipitation-related variables, especially precipitation seasonality, were the most influential drivers of habitat suitability, contributing 64.3% to the model, followed by mean monthly precipitation of the driest quarter (18.8%) and precipitation of the wettest and driest months. Jackknife tests also confirmed their critical importance. These findings underscored the sensitivity of D. costus habitat to the intensity of climate change, particularly under severe warming conditions and highlighted the urgent need for a comprehensive conservation plan. A combination of strategies, including climate-smart conservation, habitat protection, species reintroduction, and cultivation in moderately to highly suitable habitats, is crucial to ensure the long-term survival of D. costus in Pakistan amidst the changing climate.