Lim, Norman (Norman T-Lon)

The diversity of terrestrial and freshwater, non-avian, vertebrate fauna of Pulau Tekong, an island used almost exclusively by the Singapore Armed Forces, was compiled. Eighteen species of freshwater fishes, 15 of amphibians, 45 species of terrestrial reptiles, and 31 species of terrestrial mammals were recorded. Singapore records of the lizards: Ptychozoon kuhli, Luperosaurus browni, Cyrtodactylus pantiensis and the bat: Murina suilla are known only from Pulau Tekong. The island also has populations of the frogs: Limnonectes paramacrodon and Occidozyga sumatrana; the snakes: Lycodon subcinctus, Boiga jaspidea and Tropidolaemus wagleri; the lizard: Cnemaspis peninsularis, the slow loris: Nycticebus coucang, and the bats: Rhinolophus trifoliatus and Kerivoula hardwickii. These species are locally rare, and otherwise known only from the mature forests of the Central Catchment and Bukit Timah Nature reserves on Singapore Island. Pulau Tekong also supports populations of the leopard cat: Prionailurus bengalensis, the Sunda slow loris: Nycticebus coucang, the Malayan porcupine: Hystrix brachyura and the Sunda pangolin: Manis javanica—small mammals that are regarded to be rare and endangered in Singapore.

Scavenging is a common phenomenon, particularly amongst carnivorous vertebrates. By consuming carrion, vertebrate scavengers reduce resource availability for both pathogenic bacteria and their insect vectors. We investigated the ability of wild vertebrate scavengers to control agents of human diarrheal diseases (specifically Salmonella spp. and Shiga toxin- producing Escherichia coli [STEC]) in oil palm plantations in Sabah (East Malaysia), and the existence of spillover effect whereby additional vertebrate scavengers from adjacent forest patches result in greater disease control in plantation sections near these forest edges. Experimental carcasses were removed by common scavengers (Varanus salvator, Canis lupus familiaris, and Viverra tangalunga) at different time points, and this determined the length of time that the carcasses persisted in the environment. The amount of pathogenic bacteria on the surfaces of filth flies collected above the experimental carcasses was positively correlated to the duration of carcass persistence, and reduction in pathogenic bacterial abundances was largely due to carcass consumption by these vertebrate scavengers. Instead of a predicted positive spillover effect (greater scavenger activity near forest edges, hence reduced pathogen abundance), we detected a weak inverse spillover effect in which STEC counts were marginally higher in plantation sections near forest patches, and human hunting along the forest-plantation boundaries could explain this. We propose that making oil palm plantations scavenger- friendly could yield great human health benefits for the millions of workers employed in this rapidly-expanding industry, without drastically changing current management practices.