Krizler C. Tanalgo
TropiBats; Landscape Ecology Group, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences (China); Department of Biological Sciences, University of Southern Mindanao (Philippines). *This is a partial portion of the under-review manuscript based on independent research of the author. Tha author welcomes additional information, contribution for the improvement of the report. Corresponding author, tkrizler@gmail(dot)com
- The current state of bat research and conservation in south-central Mindanao is reviewed in this paper.
- The region contains a relatively high species richness of bat fauna with the representation of endemic and globally threatened species.
- However, ecological threats and disturbance are occurring in areas with known bat populations.
- More research is needed to more accurately reflect the status and distribution of bats of the Philippines, and to conserve many ecologically and economically important bat fauna in south central Mindanao.
There are currently 78 species of bats of six families are known from the Philippines (Ingle and Heaney, 1992; Heaney et al., 2010). Numerous studies have provided evidence on the importance of bats in sustaining different ecosystem services (Kunz et al., 2011; Bumrungsri et al., 2013). However, population monitoring and their ecosystem interactions are very limited especially in the Philippines (Mould, 2012). Such data is vital and many bat ecologists and conservationists have demonstrated that bat populations in many tropical regions are declining as a result of continuous human activities matched with the increasing risks to environmental changes. Local bat studies and assessment are important to determine specific issues and knowledge gaps in order to provide a refined conservation approach. Here, we provide a short review of the current status and gaps in bat research in South-central Mindanao, a biodiverse bat region but currently imperiled by various anthropogenic pressures.
1. Bat species diversity in south central Mindanao
Our review resulted into quantifying a total of thirty-one (31) bat species known to occur in the region, predominantly from forests and caves. These species belong to five (5) families and representing the 40% of Philippines bat fauna. Among bat families, Pteropodidae or the Old-world fruit bats are well represented with 14 species compared to Hipposideridae (s=4), Rhinolophidae (s=5), Emballonuridae (s=2) and Vespertilionidae (s=6). On the other hand, there are 19 species of insect bats (under 4 families) recorded from south-central Mindanao, among them is the widespread Hipposiderid Hipposideros diadema, and is the commonly recorded insect bat species. A single species locality was recorded in Pisan caves for H. pygmaeus (Tanalgo and Tabora, 2015), this species is poorly known in the Philippines. There are five species considered threatened from south-central Mindanao, including the large flying foxes Acerodon jubatus and Pteropus vampyrus2
2. Bat Research and conservation in South-central Mindanao
In 2012-2015 bat studies in the region have drastically increased and bat species recorded has doubled. The majority of the bat studies in the region were central themed to diversity and population studies. These studies mainly aimed to provide baseline information, inventory bat species in certain geographic areas and to compare species diversity of different habitat types (Tanalgo and Tabora, 2015; Nuneza et al., 2015). However, fewer studies have explored ecological aspects of bats. However, it is becoming interesting that many young researchers and budding conservationists engaging in bat research initiatives in the region are making small steps forward. Projects to build empirical information and conservation education activities to spread awareness about the importance of bats are growing among networks and institutions.
3. Threats to Bats in South-central Mindanao
Among the commonly noted threats to bats in the south central Mindanao are habitat loss and degradation and other human activities. Continuous habitat alteration is the most significant threat to biodiversity in the region. Deforestation occurs heavily and may impact many important roosting and foraging sites. In Mt. Matatum protected landscape, the continuous illegal logging and the conversion of natural forests to agricultural and plantations are among the highest threats to bats in the area (Nuneza et al., 2015). A very low diversity of bats in highly degraded habitat such as mining sites in the region has been recorded. Additionally, preliminary findings show that loud noises in mining sites caused by dynamite blasting in mining holes have affected bat activities in different sampling periods (Tanalgo et al., 2013). Destruction and unregulated tourism in caves and karst areas threaten many important underground bat sites in the region. The poor and lacking implementation of cave management are considered as important factors that hinder effective protection of many cave bats in the region (Tanalgo and Tabora, 2015; Tanalgo et al., 2016).
Hunting and consumption of bats also occur in the region. In Mt. Apo National Park, flying foxes are hunted for subsistence by many indigenous people (Tanalgo and Baleva, 2015). In caves, large fruitbats such as Rousettus amplexicaudatus and Eonycteris spelaea, and large insectivorous bats (i.e Hipposideros diadema) are hunted for food (Tanalgo and Tabora, 2015; Tanalgo et al., 2016). Local communities harvest large bat colonies by making a loud noise using pistols, smoking using coconut torch. Hunted bats are beheaded or skinned alive and sold in households at 2.00 to 3.00 (US $ .06) pesos per bat (Tanalgo et al. 2016).
Locals perceive bats as a pest and a nuisance, by causing imagined damage to orchards and fruiting crops such as durian (Durio), rambutan (Nephelium lappaceum) and lanzones (Lansium domesticum) during the peak fruiting season (June to August). There are observations of using fishnets to capture bats in many orchards and prevent bats from accessing the orchard (pers obs). The authors have personally observed hundreds of fruitbats such as R. amplexicaudatus, C. brachyotis, Eonycteris spelaea are left to die in nets. Some locals believe in the Aswang (a local half human, half bat monster folktales) and bats are associated leading them to exterminate bat individuals and colonies (Tanalgo et al., 2016).
4. Gaps on Knowledge and Research Needs
In south-central Mindanao, more data is needed to develop effective priorities for bat conservation. Despite the positive relationship between a number of studies and species richness, research themes and approaches are still lacking diversity. Accurate taxonomic examination or identification of a species are useful in assessing the state of biodiversity (Dubois (2003). In addition, it is important to properly appropriate conservation measures of the species or of the population in terms of its ecological status and endemism. Consequently, population monitoring should be among the research priorities in the region, especially for highly vulnerable species and habitats (i.e. flying foxes and cave bats).
The elucidation of bat ecosystem services in the region should be another priority. To showcase the ecological values of bats in the ecosystem are among the important keys in protecting the species at the same time maintaining the provision of their services. South central Mindanao harbors a large area of fruit crops and orchard plantation, such as Durian and Rambutan, which is pollinated fruit bats Eonycteris spealaea (Bumrungsri et al., 2013). The impacts of deforestation and other land-use types to bat population and assemblages should also be examined in the region. Oil palm and rubber plantations are currently expanding to most forested areas. Habitat loss is one of the main threats to bats worldwide (Hutson et al., 2001; Racey and Entwistle, 2003). Relative deforestation rates in Southeast Asia are the highest of any tropical region, and as much as 74% of forests may be lost by the end of the century (Sodhi et al., 2004; Miettinen et al., 2011). Additionally, the continuous climate change and land-use change may exacerbate species extinction in Southeast Asia in the near decade.
The interactions of human to bats and its habitat is also an interesting aspect of bat research to explore in the region. Illegal hunting and trade of bats from caves have also become a concern in bat cave conservation, many caves species are exploited for food, bush meat, and trade (Francis et al., 1999; Hutson et al., 2001). For example, some indigenous tribes in the Philippines believed bat meat has special medicinal properties and may cure certain diseases (Mildenstein, 2012). Bat hunting for bush meat and medicine is widespread and affects at least 167 species of bats within the tropics, and most are fruit bats and flying foxes (Mildenstein et al., 2016).
Proposed recommendation for bat conservation in South-central Mindanao
Some important recommendations to address different concerns towards bat conservation was synthesized. The following were recommended for future work and directions.
- Increase bat studies and field surveys in the region with special attention to conservation areas, the forest remains, and in caves and underground habitats.
- Establish bat research networks, collaborative science, and linkages among regional/national researchers and international researchers and organizations.
- Locate and identify areas with possible roosting sites of flying foxes, cave bats, and other large populations.
- Initiate and increase studies on ecosystem service provision, such as pest control services, pollination, and seed dispersal.
- Increase conservation-education programs especially in areas with known high bat diversities.
- Encourage and train young bat researchers in the region to sustain the need for conservationists and advocates in the region.
- Engage partnerships and increase research capacities among the students, academics, Department of Environment and Natural Resources, NGO’s and locals.
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