Spatio-temporal mapping and climate change impact on current and future expansion of P. roxburghii in the Himalayan Biodiversity Hotspot

Abstract

The global proliferation of Pinus species poses significant threats to biodiversity, ecosystem functioning, and environmental stability. Pinus roxburghii, in particular, has demonstrated a strong potential to encroach upon the indigenous biodiversity of the Himalayan Biodiversity Hotspot (HBH), an area already vulnerable to the impacts of climate change. This study utilized the MaxEnt model, chosen for its robust performance in species distribution modelling, to predict the geographical distribution and actual extent of P. roxburghii for the period 2001–2021 and project its future expansion under two shared socioeconomic pathways (SSP-126 and SSP-585) for 2050 and 2070. The model high predictive accuracy (AUC > 0.9) and metrics (κ and TSS > 0.7) demonstrate its reliability and strong performance. The results reveal a notable expansion of P. roxburghii across the HBH, with a 1.61% spatio-temporal increase (11,142.16 km²) and a 0.65% rise in habitat suitability (4478.47 km²) under future scenarios. Key bioclimatic variables influencing its distribution include BIO6 (minimum temperature of the coldest month) and BIO17 (precipitation of the driest quarter), contributing 69.54% and 85.28% to the model under current and future scenarios, respectively. These findings highlight the urgent need for targeted adaptive management strategies, such as early detection systems and habitat restoration initiatives, to mitigate the encroachment of P. roxburghii and safeguard native biodiversity.