# Divergent Effects of Climate Change on the Potential Habitats of Two Medicinally Important Aconitum Species in the Hindu Kush Himalaya

## TL;DR

Climate change is expected to reduce suitable habitats for Aconitum spicatum but expand them for Aconitum naviculare in the Hindu Kush Himalaya, affecting conservation strategies.

## Contribution

The study reveals species-specific and divergent impacts of climate change on two congeneric Aconitum species in the HKH using ecological niche modeling.

## Key findings

- Aconitum spicatum is projected to lose suitable habitats due to warming and altered precipitation.
- Aconitum naviculare is expected to expand its suitable habitats with an elevation range shift.
- Overlapping suitable habitats of the two species are predicted to decline in the future.

## Abstract

Climate change is a major driver influencing species survival and distribution, particularly for species endemic to mountainous regions. The Hindu Kush Himalaya (HKH), which is a global biodiversity hotspot and the world's youngest mountain system with a high level of endemism, is particularly vulnerable to climate change impacts. This study investigates how future climate change may affect the potential distribution of two congeneric species, Aconitum spicatum and Aconitum naviculare, both endemic to the HKH and occupying habitats with contrasting moisture regimes. Using machine learning‐based ecological niche modeling, we assessed projected changes in climatically suitable habitats under moderate (SSP2‐4.5) and high (SSP5‐8.5) emissions scenarios for two future epochs. Our results indicate that
A. spicatum
, which prefers moist environments, is projected to experience a decline in suitable habitats across much of its current range without a shift of projected elevation range, particularly in China, India, and Myanmar, due to warming and altered precipitation patterns. Conversely, A. naviculare, which inhabits semi‐arid regions, is expected to exhibit an overall expansion of suitable habitats with a shift of projected elevation range, particularly in China and, to a lesser extent, Nepal, suggesting potential emergence of new ecological niches under future climate conditions. These contrasting responses highlight the species‐specific nature of climate change impacts. Additionally, the overlapped suitable habitat areas of these two species are predicted to decline in future. While future climate change may offer new opportunities for range expansion of the currently range‐restricted A. naviculare, it may simultaneously shrink the habitat range of the more widely distributed
A. spicatum
. Suitable habitat overlaps under current and future climate scenarios of congeneric but allopatric species that we report can have ecological and evolutionary implications. These insights are critical for designing adaptive, species‐specific conservation strategies that integrate both climate projections and socioecological pressures, such as overharvesting.

Mountain endemic plants are likely to be affected significantly by climate change. Using species distribution models, we predicted suitable habitat areas of medicinally important and allopatric Aconitum spicatum and A. naviculare encompassing their entire distribution in the Hindu‐Kush Himalaya and showed that the suitable area will decline without change in elevation range for the species naturally found in wet region (
A. spicatum
) but will expand with elevation range shift for the species found in semi‐arid region (A. naviculare). These allopatric species also have their suitable areas overlapped. These insights are critical for designing adaptive, species‐specific conservation strategies that integrate both climate projections and socioecological pressures.