Sunda clouded leopard Neofelis diardi densities and human activities in the humid evergreen rainforests of Sumatra

Projected development in Borneo and Sumatra will greatly reduce connectivity for an apex carnivore

The islands of Borneo and Sumatra are strongholds for biodiversity and home for many endemic species. They also have experienced amongst the highest deforestation rates globally. Both islands are undergoing massive, rapid infrastructure development, leading to further deforestation and habitat fragmentation. Here, we identify priority areas for continued functional forest connectivity across Borneo and Sumatra, using spatial models of clouded leopard (Neofelis diardi, a forest indicator species) movement, and impacts thereto from existing and future infrastructure development. We specifically measure and map the anticipated impacts on forest functional connectivity of three major infrastructure development projects (Pan Borneo Highway, Trans-Sumatran Toll Road, and the new Indonesian capital city of Nusantara). We found that core clouded leopard habitats are already highly fragmented in Sumatra, constituting only ∼13 % of the island, with potential dispersal corridors still linking some habitat fragments. In Borneo, clouded leopard core habitats cover 34 % of the island, with one large central core area and several much smaller satellite cores, which are largely unprotected (15 % protected, compared to 42 % in Sumatra). The largest negative effect on habitat connectivity was predicted for Nusantara (66 % of the total connectivity loss predicted for all three infrastructure projects), reverberating across the entirety of Borneo with the strongest effects in East Kalimantan. The Pan Borneo Highway accounted for 28 % of the total connectivity loss, affecting every province in Borneo and Brunei, with 6 % of this decrease located within protected areas. The Trans-Sumatran Toll Road had the smallest negative effect on connectivity (6 %) but only when excluding the already built segments, which, when included, produce a total negative impact similar to that of the Pan Borneo Highway.

A Camera-Trap Survey of Mammals in Thung Yai Naresuan (East) Wildlife Sanctuary in Western Thailand

The Thung Yai Naresuan (East) Wildlife Sanctuary (TYNE), in the core area of the Western Forest Complex of Thailand, harbors a diverse assemblage of wildlife, and the region has become globally significant for mammal conservation. From April 2010 to January 2012, 106 camera traps were set, and, in 1817 trap-nights, registered 1821 independent records of 32 mammal species. Of the 17 IUCN-listed (from Near Threatened to Critically Endangered) mammal species recorded, 5 species listed as endangered or critically endangered included the Asiatic elephant (Elephas maximus), tiger (Panthera tigris), Malayan tapir (Tapirus indicus), dhole (Cuon alpinus), and Sunda pangolin (Manis javanica). The northern red muntjac (Muntiacus vaginalis), large Indian civet (Viverra zibetha), Malayan porcupine (Hystrix brachyuran), and sambar deer (Cervus unicolor) were the most frequently recorded species (10-22 photos/100 trap-nights), representing 62% of all independent records, while the golden jackal (Canis aureus), clouded leopard (Neofelis nebulosa), marbled cat (Pardofelis marmorata), and Sunda pangolin were the least photographed (<0.1/100 trap-nights). Species accumulation curves indicated that the number of camera trap locations needed to record 90% of taxa recorded varied from 26 sites for herbivores to 67 sites for all mammals. TYNE holds a rich community of mammals, but some differences in photo-rates from an adjacent sanctuary and comparisons with other research on local mammals suggest that some species are rare and some are missed because of the limitations of our technique. We also conclude that the management and conservation plan, which involves the exclusion of human activities from some protected areas and strict protection efforts in the sanctuaries, is still suitable for providing key habitats for endangered wildlife populations, and that augmented and regular survey efforts will help in this endeavor.

Carnivores and their prey in Sumatra: Occupancy and activity in human-dominated forests

Understanding the effect of anthropogenic disturbance, and its interaction with carnivores and their prey, is crucial to support the conservation of threatened carnivores, particularly in rapidly changing landscapes. Based on systematic camera-trap sampling of four protected areas in Riau Province of central Sumatra, we assessed the habitat occupancy and spatiotemporal overlap between people, potential carnivore prey, and four threatened species of medium-sized or large carnivores: Sumatran tigers (Panthera tigris sumatrae), Malayan sun bears (Helarctos malayanus), dholes (Cuon alpinus), and Sunda clouded leopards (Neofelis diardi). To assess spatial overlap of target species, we used single-species occupancy models and applied a Species Interaction Factor (SIF) to conditional two-species occupancy models. We also used kernel density estimation (KDE) to assess temporal overlap among these species. Our habitat use models showed that altitude (elevation) strongly influenced the occupancy of all large carnivores and potential prey species. Except for Sunda clouded leopards, the occurrence of large carnivore species was positively related to the spatial co-occurrence of humans (SIF > 1). In addition, we found that sun bears and dholes both exhibited high spatial overlap with tigers, and that sun bears alone exhibited high temporal overlap with people. Our findings contribute to an improved understanding of the contemporary ecology of carnivores and their prey in rapidly changing, southeast Asian landscapes. Such knowledge is important to the conservation and recovery of large carnivores in conservation hotspots that are increasingly dominated by humans across Sumatra, as well as globally.