Cave Bats

Bats spend the majority of their lives in roosts, which provide shelter from the environment and predators, a secure place to mate, rear young and interact with other individuals. Because of their size, permanency and stable microclimates, caves make excellent roost sites, and are used by at least 40% of Southeast Asia’s bat species. Some species roost in huge aggregations, with numbers exceeding 100,000 individuals (e.g., species of Rhinolophidae, Hipposideridae and Miniopterinae) and congregations of millions of free-tailed bats (Molossidae) are known from caves throughout Southeast Asia. Complex limestone karst systems, with an array of microclimate and light regimes, support the greatest diversity and abundance of bats. These critical “Biodiversity Arks” cover >400,000 km² in Southeast Asia and can serve as crucial population reservoirs for cave-roosting bats, subsidizing diversity levels in forest fragments that might otherwise decline over time.

The threats to cave bats are many-fold. Direct hunting of bats at caves is an immediate pressure on bat populations in many countries, but other human activities, such as tourism, the collection of guano or cave swiftlet nests, if sustained, can have severe consequences for the long-term viability of the bat populations. Regionally, quarrying of karst areas for limestone and basement minerals probably represents the greatest threats to cave-dependent species. Southeast Asia has the highest annual quarrying rates in the tropics (178 million metric tons per year) and the rate is increasing by 5.7% each year.

Research Need and Justification: The significance of caves to bat diversity and the multitude of threats to cave-bat populations are widely recognized (Hutson et al. 2001, Struebig et al. 2009), but there are no national-level cave bat assessments documenting cave bat distribution and threats, relatively few surveys given the extent of karst systems across Southeast Asia, and no standardization of survey methods to facilitate regional assessments. Further, cave resources (cave swiftlet nests, guano, limestone, bats as food, tourism) often make critical contributions to local economies, and the caves themselves may be of cultural/religious significance. Research into management practices that minimize human-bat conflicts and interactions in cave systems is urgently needed, as is research into ecological and economic benefits provided by cave bats.

Model: Bat Conservation International, Nina Ingle (Wildlife Conservation Society of the Philippines, and Jodi Sedlock (Lawrence University) have collaborated with Philippine NGOs (e.g. Philippine Biodiversity Conservation Foundation) for the past three years to enhance protection of caves and cave resources in the Philippines. Extensive training of Filipino conservation biologists and government staff culminated in a workshop on cave bat identification at the Philippine Cave Congress in April 2010 and the production of a guide to the cave bats of the Philippines. In January 2011, 50 participants (bat biologists, cavers, and staff of the Department of Environment and Natural Resources) joined a 4-day workshop on assessing the status of Philippine cave bats.  Cave bat observations from participants and others are being collected through the webpage phcavebats.crowdmap.com.

Global Actions: (1) Develop effective networks of cave and bat conservation researchers and managers (government and non-government) throughout Southeast Asia; (2) Review karst, cave, and bat conservation legislation and management systems and their effectiveness in different Southeast Asian countries; (3) Compile existing information on cave bats in Southeast Asia; (4) Expand the capacity of researchers, managers, and conservationists working with cave bats throughout Southeast Asia; (5) Enhance  cave survey efforts across Southeast Asia to identify and prioritize caves supporting the highest diversity of bats or populations performing key ecological functions in the local context and document management approaches and effectiveness; (6) Develop cave management plans that recognize scientific, cultural/religious and economic values of caves and provide for the protection of bats; and (7) Establish effective outreach and education programs.

Needs Assessment: (1) Identify existing networks and key individuals from cave and bat conservation researchers and managers (government and non-government) throughout Southeast Asia; (2) Assess the effectiveness of karst, cave, and bat conservation legislation and management systems throughout Southeast Asia; (3) Collate existing information on cave bats throughout Southeast Asia from diverse sources including caving groups, government reports, and published information; (4) Systematic survey methods for assessing and monitoring a) bat diversity and population status and population health; b) resource use in and around caves that affect cave bat populations; c) disturbance and stressors at caves and in surrounding landscape; (5) Establish workshops to train bat surveyors in systematic cave bat assessment methods; and (6) Facilitate systematic cave assessments throughout Southeast Asia, including evaluating the impact of current and historical anthropogenic disturbance, collection of bats for food, and risk of disease transmission.

Projected Outputs: (1) National and regional cave bat status reports on the distribution, threats, and management context and approaches for cave bats; (2) Identification of cave systems of greatest importance for bat conservation, and determination of  the major threats and conservation context; (3) Monitoring to assess the success of conservation intervention; (4) Management practices to minimize the impact of human activities; (5) Educational materials and activities for bat conservation in Southeast Asia; and (6) Case studies of effective bat research and management programs.