Search

The Philippine mouse deer (Tragulus nigricans) is an endangered ungulate species, endemic to the Balabac Islands in the Palawan Faunal Region of the western Philippines. Despite its conservation importance, it has received little attention from local authorities and conservation biologists, with limited studies conducted on the species. Here we provide a preliminary report on the species distribution, population and conservation status, based on our recently completed surveys. We used a combination of line transect distance sampling, opportunistic searching on targeted habitats, and informal community interviews to assess the species’ status. We recorded a total of 25 sightings of mouse deer during our transect surveys. All records, including recent sightings of mouse deer, were from two islands, mainland Balabac and Bugsuk. No mouse deer were recorded on other islands that we surveyed, suggesting that the populations have been markedly reduced due to a nearly complete conversion of natural habitat, such as Ramos Island, or perhaps some islands are too small to permanently support populations. Our analyses revealed that the species occurs at low density (0.219 ± 0.084/ha), particularly on Balabac. The mean population estimate based on Bayesian analysis is 2525 (95% Highest Density Interval, 1635–3461). However, this number is highly uncertain because of the low probability, highlighting the need for more information on the species’ population. Several conservation efforts are being implemented now, but more intensive in situ conservation programs would benefit the species, along with other threatened endemics found in the region.

Information on species richness and community structure is invaluable for guiding conservation and management of biodiversity, but is rarely available in the megadiverse biodiversity conservation hotspot of Philippines – particularly for amphibians and reptiles. This study provides the first report and characterisation of amphibians and reptile communities across primary habitat types of the Victoria-Anepahan Mountain Range on Palawan Island along the western edge of the archipelago. A total of 41 amphibian and reptile species were recorded throughout our sampling sites (n = 27 species) or in targeted habitat searches (14 species). A species richness estimator predicted that 35 species may be present in our sampling sites, suggesting that a significant proportion of secretive species may continue to be unrecorded, especially for reptiles. Higher species richness was found in secondary growth than in mixed-use agricultural areas or even pristine forest. The low species richness recorded from pristine forest types may be due to these forests now being restricted to higher elevations where species diversity has been documented to decrease. Our results also show that complex community structures (species assemblages) are to be equally expected in both secondary growth and pristine forests. Together, our results show how species richness and community assemblages may vary across habitats, highlighting that old growth forest does not always support higher species richness, particularly in high elevations.