Occurrence and Habitat Use of Non-native Small Mammals in Upland Urban-Forest Environment in Northern Philippines

In the Philippines, few researches have been conducted about small mammals in urban areas at high elevation, where forests remain and non-native pest species can proliferate. Previous studies in Baguio City, Benguet Province reported three non-native species. This study extended these prior surveys by sampling in 13 localities, employing standard trapping method to document the distribution of species in an urban-forest setting. In 4,711 trap nights, 94 individuals were captured, consisting of four non-native species: Rattus exulans, Rattus tanezumi, Mus musculus, and Suncus murinus. Analysis of occurrence and relative abundance of species showed that small mammal distribution varied among the habitats, and appeared that variation may have been related to differences in vegetation structure or a habitat’s disturbance level. Rattus tanezumi was the most widespread, being especially common in backyard farms and in the public market. Suncus murinus was also widespread but less abundant than R. tanezumi. Rattus exulans was uncommon and restricted to certain area of a given habitat, particularly preferring weed-dominated areas. These suggest that non-native species are common and widespread in urban-forest setting but with apparent habitat preferences. The non-detection of native species is notable, suggesting that thorough studies can be done in the future.