Indonesia – Tracks and signs in the Buton forest

Written by Tom Martin

Photos courtesy of Peter Taylor

The forests of Buton Island (the location of our Indonesian terrestrial study site) are home to several species of large endemic mammal. All these mammals remain poorly studied, partly because Wallacean species have been neglected by zoologists generally, but also because they are extremely hard to even observe, let alone study. Their shy nature and the dense forests in which they live make monitoring populations using distance sampling, and other techniques relying on direct observations, very difficult. This means scientists working on the megafauna monitoring project here have to rely on recording indirect tracks and signs of these species, such as the Lowland Anoa (Bubalus depressicornis) footprint and Sulawesi Wild Pig (Sus celebensis) nest in these photographs. These indirect signs allow researchers to build up patch-occupancy models for Buton’s cryptic forest mammals, which indicate the spatial extent of the forest these species inhabit, and how this changes over time. By analysing patch occupancy over multiple years, Opwall fieldworkers can assess inferential population trends in these species, even if they actually see only a few individuals during the survey period. Long-term occupancy patterns in wild pig suggest populations here are large and stable. The story this kind of analysis tells of Buton’s anoa population, however, is sadly fairly bleak. Detection rates of this species’ tracks and signs have declined steadily since surveys began, indicating the total population on the island continues to shrink on an annual basis. Unless swift conservation action is taken, it could be that this unique wild buffalo disappears from Buton completely within the next decade or so. This would be a major blow to the conservation of the species; Buton is considered a crucially important stronghold for the anoa, supporting around 10% of the entire global population. Safeguarding remaining anoa populations is therefore an extremely high priority, and much of the REDD+ funding currently being applied for by Operation Wallacea  will, if successfully acquired, be used to help reverse the downward spiral of anoa numbers by improving enforcement, education, and providing sustainable alternative livelihoods to hunting.

1) Pig Maternity Nest

2) Lowland Anoa Tracks