Habitat suitability modelling of endangered medicinal plant, Aconitum heterophyllum Wall. Ex Royle in the Western Himalaya

Climate change is considered one of the major threats to species extinction. The impact of climate change on the distribution of Aconitum heterophyllum, an endangered species in the northwestern Himalayan state of Himachal Pradesh, remain largely unexplored. In this study, species occurrence data, bioclimatic variables and population distribution data were used to map the current and future distribution (2050 and 2070) of A. heterophyllum. The Species Distribution Modelling (SDM) based on Maximum Entropy (MaxEnt) algorithm driven by climate data from the Global Circulation Model, HadGEM3-GC31-LL, which is statistically downscaled to 1 km spatial resolution was used for species distribution mapping. Here, we consider three future scenarios: Shared Socioeconomic Pathways (SSPs) - SSP126, SSP245, and SSP585. The Bioclimatic variables (Bio 15), which is precipitation seasonality and elevation, were found to positively influence the distribution of A. heterophyllum in the studied locations. Precipitation seasonality ensures adequate water availability at cold and dry habitats. Also, higher elevations corresponded to high suitable habitats in the Himalaya. The SDM predicted a total suitable area of 1863.7 km² A. heterophyllum in Himachal Pradesh. Under SSP126, which represents moderate development with minimal environmental degradation, the suitable habitat is projected to decrease by 51.28%by 2070. Under SSP245, which represents moderate development with more pronounced environmental degradation, the suitable habitat is predicted to decrease by 53.64%in the mean by 2070. Under SSP585, representing fossil-fuelled development and successful mitigation of environmental issues, the suitable habitat is predicted to decrease by 54.61% by 2070. Overall, the species is expected to loose 30.68–58.51% of its current habitat between 2050 to 2070, posing a significant extinction risk in the future. Based on the classified layers, the highly suitable areas were found to be overlaying within the Dhauladhar ranges, alpine regions of Pin Valley National Park, Killar ranges of Chamba, Great Himalayan National Park, Parvati glacier, Gramphu, Indrasan Peak and Inderkilla National Park. These regions were identified as areas for key conservation efforts and are crucial for implementing adaptive management strategies to enhance the protection and sustainable use of A. heterophyllum in Himachal Pradesh in the face of global climate change.

Keywords: Species Distribution Modelling, Northwestern Himalaya, Shared Socioeconomic Pathways, Climate change, Endangered