Medicinal plants in peril due to climate change in the Himalaya

Abstract

Climate change is causing many irreversible changes in the Himalayan ecosystems. In this study, an attempt was made to understand the ecological response of medicinal plant species to changing climate conditions in the Sikkim Himalaya, a part of the Eastern Himalayan biodiversity hotspot. Maximum Entropy Species Distribution Modelling (SDM) approach was used to analyze the potential habitat distribution of 163 medicinal plant species in current and future climates (2050, 2070). An attempt was also made to identify the most suitable areas for conservation and test the effectiveness of the existing Protected Area (PA) network in conserving medicinal plant species in current and future climate scenarios through the Habitat Suitability and Overlap Analyses. SDM analyses revealed that the majority of the medicinal plant species are found in the tropical and sub-tropical regions in the Sikkim Himalaya (300–2000 m) at present. In future climates, however, most of the species are likely to show an upward and northward shift in their distributions. Maximum species-rich regions are likely to shift by 200 m and 400 m in 2050 and 2070, respectively. A total of 13–16% of medicinal plant species currently found in the region are likely to lose their existing potential habitats by 2050 and 2070. The results highlight that species that are restricted to specific localities and have a narrow elevational distribution are the most vulnerable species and likely to go extinct due to climate change in the Himalaya. Habitat suitability analyses indicated that elevations ranging from 860 to 2937 m serve as highly suitable habitats for medicinal plant species in Sikkim Himalaya. Consequently, these areas can be focused for conservation actions in order to mitigate the effect of climate change. The results of Overlap Analysis indicated that out of 8 PAs in Sikkim Himalaya, only 5 PAs are effective in the conservation of medicinal plant species in current and future climates. The boundaries of existing PAs need to be expanded in order to accommodate the upward shifts in the spatial distribution of species, especially in the case of those PAs that are located in the lower elevations or tropical regions. This study provides a novel integrated framework for use of ecological informatics in assessing the species vulnerability to climate change and planning conservation priorities.