Five pteropids have gone extinct in the last few decades. P. brunneus has disappeared from Australia, P. pilosus from Palau, P. subniger from the Mascarene Islands, P. tokudae from Guam, and Dobsonia chapmani from the Philippines. All Pteropus spp. and five members of the genus Acerodon are listed in CITES Appendix II (Mohd-Azlan et al., 2001).
Human disturbance, such as hunting and encroachment into fruit bat habitat, and habitat destruction, factor heavily in declines of pteropids in Malaysia. Existing colonies of P. vampyrus, a species particularly susceptible to anthropogenic disturbance, are restricted to areas that are uninhabited, remote, and inaccessible (Mohd-Azlan et al., 2001). In the late 1980s, hunters from peninsular Malaysia reported they had had increasing trouble locating P. vampyrus colonies for the previous ten years and had observed fewer bats in orchards (Fujita, 1988).
Bats are hunted for consumption, protection of crops (including deliberate colony eradication) and sport. Muslims do not eat bats for religious reasons, but many Chinese and Manadonese consider bat meat a delicacy; P. vampyrus is the only pteropid traded to “a significant extent” in Malaysia and Indonesia (Fujita, 1988). Without protective measures, crop losses to bats can be as high as 20%. Squirrels and macaques, which eat ripe and unripe fruit, are considered worse pests by farmers (Fujita,1988). It is apparently common practice for local hunters to wait on roads and shoot bats as they fly overhead. Bounties for P. vampyrus in the flowering and fruiting season can be as high as $2; bats are sold in markets for about $3 (Fujita, 1988). Interviews with residents of Kuala Benet suggest that a local colony of P. vampyrus was either extirpated, or abandoned the site, in the face of excess disturbance. The colony had been at the site since at least 1988 and disappeared in 1999. In 2001, Malay law permitted hunting licenses entitling bearers to kill up to 50 individuals. No limit had been placed on the number of licenses distributed. The Protection of Wildlife Act of 1972, which applies only to peninsular Malaysia, prohibits the shooting of P. vampyrus after midnight or around roost sites (Mohd-Azlan et al., 2001).
In Endau-Rompin State Park, state forestry officers and an aboriginal chief reported rapid declines in P. vampyrus after selective logging and before the area was declared a park. Aquaculture, especially cultivation of the tiger prawn, the woodchip industry, agriculture, port facilities (Kelang, Selangor), airports (Bayan Lepas, Penang), reservoirs (Johor) and industrial estates (Batu Maung, Penang) have contributed to the destruction of 20% of peninsular Malaysia’s mangrove swamps (Mohd-Azlan et al., 2001). Less obvious types of habitat modification, such as changes in plant species assemblage, affect bats’ roosting and foraging opportunities. Comparing bat abundance and diversity between the Bangi Forest Reserve, Selangor, which was selectively logged from 1948 to 1976, and the undisturbed Krau Wildlife Reserve, Pahang, Zubaid (1993) found a significantly greater number of species in the undisturbed habitat. There were also significantly more megachiropterans than microchiropterans in the disturbed versus undisturbed habitat (46% v. 18%). Notably, Eonycteris spelaea was present only in the undisturbed forest, and Scotophilus kuhlii was present only in the disturbed forest. Cynopterus brachyotis was present at both sites; P. vampyrus and P. hypomelanus were not recorded at either. Zubaid suggests that logging heavily influences insect abundance, thereby disproportionately affecting microchiropterans.
Pteropus spp. have been in decline in Australia for at least 90 years (Spencer et al., 1991). The IUCN has declared P. poliocephalus and P. conspicillatus “vulnerable,” and P. macrotis “rare” (Richards, 1995). The conversion of eucalypt forests and rainforests to agricultural land is considered a much greater contributor to the decline of P. poliocephalus than shooting for crop protection; however, the impact of shooting at maternity camps for sport has not been fully assessed (Mickleburgh et al., 1992).
Author: S. Cobey.