Study area
South Asia covers an area of approximately 3.75 million sq km, and comprises the countries of Afghanistan, Bangladesh, Bhutan, India, the Maldives, Nepal, Pakistan, and Sri Lanka (Figure 1). The region consists of four broad climate zones (Oliver, 2005): dry subtropical in the far North, equatorial in the far South, alpine in the mountainous regions, and tropical (with regional variations) in most of the rest of the subcontinent. According to the Koppen-Geiger climate classification system (Peel et al., 2007), the region comprises 15 different climatic subtypes, dominated by subtropical climates (humid summer, dry winter) in the north and the Indo-Gangetic plain, and tropical savanna climates (wet and dry) in the central, eastern, and peninsular regions. Most of the west and north-west of South Asia consists of arid and desert climates. Due to the large topographical variation in this region, the variety of elevations, soil types, and biomes in South Asia is very complex (Ramankutty et al., 2018). To avoid biases based on political boundaries, the focal area for the analysis was defined by a rectangular extent around the borders of South Asia (Figure 1). Due to the Himalayas and trans-Himalayan regions forming a barrier to bat movement and presence (Ruedi et al., 2008; Thapa et al., 2021), the regions of China that fell under this extent were removed, thus creating a dispersal boundary on the northern border of Nepal, which coincides with the Himalayas. Additionally, due to distance and isolation from most of the study area, a small region of Indonesia (Sumatra) within the study extent was removed (Figure 1). Three of the world’s major biodiversity hotspots (Myers et al., 2000): Himalayas, Indo-Burma, and the Western Ghats and Sri Lanka, are located within the focal area for analysis.