FLYING FOXES OF THE NORTHERN SIERRA MADRE NATURAL PARK, NORTHEAST LUZON Merlijn van Weerd, Jessie P. Guerrero, Bernard A. Tarun and Dominic G. Rodriguez 1 ABSTRACT Giant fruit bats are spectacular animals that are popularly called flying foxes. Flying foxes are important pollinators and seed dispersers and are considered key-stone species in tropical forest systems. Most flying fox species are threatened because of over-hunting and habitat destruction. Four species can be found in the Northern Sierra Madre Natural Park (NSMNP): the Mottle-winged flying fox (Pteropus leucopterus), the Large flying fox (Pteropus vampyrus), the Golden-crowned flying fox (Acerodon jubatus) and the Common island flying fox (Pteropus hypomelanus). P. leucopterus and A. jubatus are endemic to the Philippines and both are classified as endangered in the IUCN Red List 2000. P. leucopterus is a poorly known species but seams to be uncommon though widespread in the Northern Sierra Madre in ultra basic and disturbed lowland forest. P. hypomelanus was not observed by us but it was recorded in the park during earlier surveys. A. jubatus and P. vampyrus live in roost sites that historically could number hundreds of thousands of animals. Two roost sites are located within the NSMNP: one in the municipality of Divilacan with an estimated number of one hundred twenty thousand bat, and the other in the municipality of Dinapique with an estimated twenty-five thousand. Both roost sites are situated in ultra basic forest near the Pacific Ocean. Ultra basic forest is a rare forest type characterized by inhibited tree growth with a low canopy, small trees and high tree density on basic soils. Hunting pressure is moderate in Divilacan and very high in Dinapique. Both roost sites are situated in a protected area but effective law enforcement or hunting agreements do not exist at the moment. The roost site in Dinapique was deserted in April 2002. Periodic transfer of bats to other roost sites is being observed in Divilacan and in other countries as well. Still, it seems that the Dinapique roost site needs additional protective measures. The ecological role of the flying foxes within the ecosystems of the NSMNP should be studied further. Flying foxes, if hunted on a sustainable level, offer additional protein and cash for local hunters. The roost site at Divilacan could become an eco-tourism destination. INTRODUCTION Flying foxes are fruit bats belonging to the family Pteropodidae. Formally, all species within the genus Pteropus are called flying foxes, including the smaller species within this group (Nowak 1999). Giant Fruit Bats (including species of the genus Acerodon) with a wingspan of more than a meter are often called flying foxes. In this paper "flying fox" refers to these giant fruit Bats. Some flying fox species roost in colonies that can reach up to hundreds of thousands, and in historical times millions, of individuals. Other species are solitary (Nowak 1999). Fruit bats are important seed dispersers and pollinators (Kalko et al. 1996, Marshall 1983, Banack 1998) and are often identified as key stone species in tropical forests: species that play a pivotal role in ecosystem functioning (Power et al. 1996, Cox et al. 1991). Most flying fox species are nocturnal (Nowak 1999) and are capable of making foraging flights of many kilometers (Shilton et al.1999). One can imagine the impact of thousands of Giant fruit bats feeding on fruit each night and dispersing the seeds over a wide area. 1 Paper presented at the 4th Regional Conference on Environment and Development in Cabagan, Isabela in 2002. Cite as: Van Weerd, M. et al. 2003. Flying foxes of the Northern Sierra Madre Natural Park, Northeast Luzon. In: Van der Ploeg, J., E.C. Bernardo and A.B. Masipiquena (eds.), The Sierra Madre mountain range: global relevance, local realities. CVPED and Golden Press, Tuguegarao, the Philippines, pp. 54-62.