Threatened predator on the equator: multi-point abundance estimates of the tiger Panthera tigris in central Sumatra

Abstract

Information on spatial and temporal variation in abundance is crucial for effective management of wildlife. Yet abundance estimates for the Critically Endangered Sumatran tiger Panthera tigris sumatrae are lacking from Riau, the province historically believed to hold the largest percentage of this subspecies. Recently, this area has had one of the highest global rates of deforestation. Using camera traps we investigated tiger abundance across peatland, flat lowland, and hilly lowland forest types in the province, and over time, in the newly established Tesso Nilo National Park, central Sumatra. We estimated densities using spatially explicit capture-recapture, calculated with DENSITY, and traditional capture-recapture models, calculated with CAPTURE. With spatially explicit capture-recapture the lowest tiger density (0.34 ± SE 0.24 per 100 km 2 ) was estimated in the hilly lowland forest of capture-recapture the spatially explicit capture-recapture approach resulted in estimates 50% lower. Estimates of tiger density from this study were lower than most previous estimates in other parts of Sumatra. High levels of human activity in the area appear to limit tigers. The results of this study, which covered areas and habitat types not previously surveyed, are important for overall population estimates across the island, provide insight into the response of carnivores to habitat loss, and are relevant to the interventions needed to save the tiger.

Potential for camera-traps and spatial mark-resight models to improve monitoring of the critically endangered West African lion (Panthera leo)

“…Camera-trapping techniques using a capture-recapture framework (O'Connell et al 2010) have proven very effective in estimating population size and density of elusive and cryptic large carnivores such as tigers (Panthera tigris) in India (Karanth 1995;Karanth and Nichols 1998) and Sumatra (Sunarto et al 2013), jaguars (Panthera onca) in Belize (Silver et al 2004) and Brazil (Silveira et al 2010), and leopards (Panthera pardus) in Nepal (Thapa et al 2014) and South Africa (Balme et al 2009). Camera trapping for carnivores, especially felids, is now widely used for abundance and density estimation and greatly improves our understanding of wildlife population status (Meek et al 2014).…”

Cat coexistence in central Sumatra: ecological characteristics, spatial and temporal overlap, and implications for management

“…Camera trapping originally focused on Sumatran tigers but also yielded images of other wildlife species (Sunarto et al ., ). Five systematic sampling blocks (∼160 km 2 each) were selected from the major forest blocks in approximate proportion to their occurrence in the landscape (Fig.…”

“…This cell size was originally chosen based on its practicality for field navigation, and analysis related to home‐range use of tigers to ensure ‘non‐zero probability of being photographed’ under capture‐mark‐recapture assumptions. We also used opportunistic camera placement for 1–3 months in additional areas across the landscape (Sunarto et al ., ). No baits or lures were used.…”

“…Our study area is generally categorized as lowland (<500 m) with elevation across camera stations ranging from 6 to 460 m. A more detailed account of the area is available in Sunarto et al . (, ).…”

“…As a by‐product of active tiger research in central Sumatra (Sunarto et al ., , ), information on other wild cats is available through tiger camera trapping studies. We used this information to investigate natural history, ecological characteristics and potential for species interactions of the Sumatran cat community, which appears to consist of competing sympatric species.…”