Assessing Climate Extremes and Composite Vulnerability in South Asian Key Biodiversity Areas

Key Biodiversity Areas (KBAs) in South Asia are ecologically important, yet many are increasingly exposed to climate extremes and human pressures. Integrated assessments that combine climate extremes, species vulnerability, and anthropogenic pressures remain limited for the Key Biodiversity Areas of South Asia. This study develops a combined framework to evaluate climate hazards and multidimensional vulnerability across more than 800 KBAs.

Species vulnerability scores were calculated using IUCN distribution range maps for threatened birds, reptiles, amphibians, mammals, and plants, which were intersected with KBA boundaries to calculate species vulnerability based on the number of IUCN-threatened species present in each KBA. Anthropogenic vulnerability was calculated using the global human-pressure map, representing pressures from built environments, agricultural areas, population density, transportation networks, and night-time lights. The initial climate analysis includes temperature trends, precipitation trends, and the calculation of ETCCDI indices (such as TXx and WSDI) using ERA5 observational data (1951–2014) and CMIP6 model outputs.

The preliminary results indicate that warming patterns are most pronounced across the Himalayas, northeastern India, and parts of the Western Ghats. Several species-rich KBAs are in rapidly warming or strongly human-modified landscapes, suggesting heightened ecological sensitivity. Extended climate analysis includes precipitation-extreme indices to provide a more complete representation of hydro-climatic variability.

Biological, anthropogenic, and climatic components are combined to form a composite vulnerability index. This index is integrated with climate-extreme hazards to produce a Climate–Biodiversity Risk Index for each KBA. The framework provides a practical and data-driven basis for identifying KBAs where climate extremes and vulnerability factors overlap, supporting improved conservation and climate-adaptation planning across South Asia.