Making conservation easy among policy-makers and implementers were among the challenges for successful and sustainable conservation of diverse taxa and across different taxa. Among the strategies practiced by conservation biologists is the use of indices to determine important species or communities to conserve, or to prioritize areas with urgent conservation intervention needs (Borges et al. 2012; Donato et al. 2014).
Among these habitat types are caves and underground habitats. In caves, bats are important keystone species as they facilitate ‘energy’ transfer from the outside environment to the inside. Caves are used by bats for a variety of reasons, including courtship and mating, raising young, and hibernating. Bats seek shelter during the day and disperse from these sites to forage for food at night. In addition, many insectivorous species retreat to caves between feeding bouts, where they may pull the wings and heads of insects that were captured while foraging. Frugivorous species sometimes transport large fruits to caves where they cull soft pulp and where they can reduce the risks of predation. In temperate regions, some species that roost in foliage or tree cavities in the warm months hibernate in caves during the winter. However, human activities and exploitation threaten many cave and karst ecosystems and the endemic species within these systems (Clements et al. 2006; Ball 2002; Niu et al. 2007). For example in Southeast Asia, bat caves including karst areas are among the most threatened ecosystems due to continuous human exploitations. Therefore, it is urgent to identify and protect threatened cave and karst system to circumvent current species declines of many important species (Beyben & Townsend 2005).
Previously Developed Cave Conservation Indices and the Innovations within Bat Cave Vulnerability Index
There were several indices developed to evaluate various aspects of cave biological and geophysical value. To date, the Eurobat scheme is the only index which has been developed to grade caves using bat diversity (Mitchell-Jones, 2000). However, the index does not suggest prioritization and was based only on species diversity (i.e. richness and abundance) and conservation status and fails to incorporate other species attributes (rarity and endemism) or habitat attributes and threats at this point. Additionally, other indices and methodologies have been developed to identify and protect cave sites using various cave taxa but failed to include and consider habitat attributes (see Elliot, 2005; Elliot, 2007; Borges et al., 2008; Gabriel et al., 2008; Donato et al., 2014). Because of this, there is no unified method in the prioritization of caves for conservation and protection in the region or more widely. Therefore, the development and establishment of a standardized method of evaluating caves are necessary as part of an inclusive conservation strategy to improve prioritizing bat caves for conservation. We present a new approach to prioritizing caves including both biotic value and threats, the ‘Bat Cave Vulnerability Index’ (BCVI). This method provides an index specifically tailored for bat cave conservation that encompasses the cave biotic potential and habitat vulnerability as components of an index, as a first step in developing priorities which maximize the effectiveness and efficiency of conservation.