The mammals of Mt. Amuyao: a richly endemic fauna in the Central Cordillera of northern Luzon Island, Philippines

Faunas of old oceanic islands often have extremely high levels of endemism and are considered highly susceptible to anthropogenic disruption. We surveyed the richly endemic small mammal fauna on Mt. Amuyao in the Central Cordillera of northern Luzon Island, Philippines. We tested hypotheses regarding elevational patterns of species richness and community composition, community response to habitat disturbance, and interactions of native and non-native mammals. Our study revealed greater species richness and faunal heterogeneity within the Central Cordillera than previously suspected. We documented 15 native species (14 rodents and 1 insectivore), and two species of non-native rodents. All of the native species are endemic to the Philippines, eight being restricted to the Cordillera. Twelve of the 14 native rodents belong to two ancient endemic clades, indicating that most of the regional diversity is the product of in situ speciation. Native mammal assemblages are ecologically diverse, and include species with varied trophic habits, activity patterns, and climbing ability. Some native species are restricted to relatively pristine habitat, whereas others are highly tolerant of disturbance. Non-native species are restricted to highly disturbed habitats and apparently are displaced by natives where habitat has regenerated from past disturbance.