Presence-absence modelling (McKenzie et al. 2002, 2003) of camera-trapping datafor all 16 study sites on Borneo and Sumatra were tested and proved to be robust enough toestimate a range of population sizes in these sites. The largest median population estimatewith 50% range overlap was 873 ± SE 197.1 adult bears in Kayan Mentarang National Park(1.4 million ha) in East Kalimantan at a density of 0.042 bears/km-2. In the adjacentunprotected lowland Bulungan Forest (4,226 ha) densities were lower (0.025 bears/km-2)with an estimate of 156 ± SE 48.6 adult bears. In Sumatra’s Gunung Leuser National Park(800,000 ha) the population estimate was 280 ± SE 61.2 adult bears at a density of 0.023bears/km-2. Lower densities in Sumatra and the Bulungan region are likely due to moreextensive habitat loss, fragmentation, and hunting. Although hunting occurs in KayanMentarang National Park, habitat disturbance is minimal. All estimates accounted for theproportion of consistently occupied habitat, along with gaps between ranges, and areconsistent with published densities for the sun bear’s closest phylogenetic relatives.Results indicate that the IUCN Red List (v. 3.1) for H. Malayanus can be updatedfrom Data Deficient (DD) to Vulnerable (VU C2ai) in Indonesia. Considering the lowabundances in Indonesia, which likely stewards the largest populations and protected areas inthe sun bear’s global range, the species may be Endangered (EN, based on criteria B1bi-v,C2ai and D) or Critically Endangered (CR, based on criteria B1a and B1bi-v) in regionswhere they are more isolated. These data also support the CITES Appendix 1 listing that H.malayanus probably is in danger of extinction and is or may be affected by internationaltrade. The bear’s affinity for primary forest and the increasing rate of forest loss suggestscientifically-based conservation measures should be implemented without delay. A timeand space mosaic can help planners create ecologically-sound reserve networks in thesefragmented landscapes.This was the first study of its kind to generate empirically-based density andabundance estimates of sun bears, and this is the first study of bears using presence-absencemodelling, such as that proposed by MacKenzie et al. (2002, 2003), to produce theseestimates. Thus, these estimates only provide an initial baseline, for which further researchshould validate and examine trends through multi-year mark-recapture studies in

representative habitat types and conditions across the bear’s range.Hunting is affecting sun bear populations in some areas, but in Indonesia the mostimmediate threats to sun bear persistence are presently forest loss and disturbance. Sun bearsurvival depends on (a) our ability to predict how biogeographic conditions, changinglandscape structures, environmental stochasticity, and anthropogenic disturbances affect bearmovement and foraging patterns across time and in increasingly patchy landscapes, (b)improving long-term bear access to critical resources and habitat, and (c) implementingspecies and habitat-specific protective mechanisms at landscape scales.vCONTENTSPreface iSummary iiAcknowledgements xiChapter 1 Introduction and Objectives 11.1 Introduction 21.2 Addressing the Issues 41.3 Research Summary 61.4 Historic Context 71.5 Principal Issues 101.6 Prior Conservation Action and Recommendations 141.7 Study Goals and Objectives 151.7a Specific Goals 151.7b Specific Objectives and Questions 16Objective 1: Sun Bear Ecology, Habitat, and Landscape Use 16Objective 2: Sun Bear Density, Abundance, and Distribution 17Objective 3: Analysis of Biogeographic and Disturbance Effects 17Objective 4: Local Professional Development 19Objective 5: Public Education 19Objective 6: Recommendations and Conservation Planning 19Chapter 2 Sun Bear Evolution and Biology 202.1 Sun Bear Evolution 212.2 Sun Bear Morphology 242.3 Sun Bear Biology 252.3a Prior Research 252.3b Reproduction 262.3c Foraging Ecology 272.3d Competitive Relationships 282.3e Agonistic Relationships 282.3f Ranging Patterns 292.3g Biogeographic Ecology 30Chapter 3 Theoretical Framework 343.1 Island Biography Theory and Population Persistence 353.2 Foraging Theory and Habitat Selection 463.3 Disturbance – Risk Hypothesis 52vi

3.4 Perturbation – Stress Hypothesis 553.5 Metapopulation Dynamics 65Chapter 4 Study Areas, Feasibility Study, and Experimental Design 724.1 Introduction 734.2 Sumatra 744.2a The Leuser Ecosystem 764.3 Borneo 804.3a Kayan Mentarang and Bulungan Ecosystems 834.4 Feasibility Study 894.4a 2000 Preliminary