Elusive Sumatran rhinos: Population profiles needed

(This article was originally published in The Horn, autumn 2014. Author: Bill Konstant - Program Officer, International Rhino Foundation)

The Sumatran and Javan rhinos are possibly the rarest and most endangered large mammals in the world. Their combined populations probably number less than 175 animals. Sumatran and Javan rhinos were once bountiful and ranged over many hundreds of thousands of square miles stretching from India to Indonesia. Today, however, they survive almost entirely as relict populations in a handful of scattered tropical forests; the future for both species lies almost entirely in the hands of Indonesian wildlife authorities; and continued support for intensive monitoring and protection efforts is the last hope for avoiding extinction.

Elusive Sumatran rhinos: Population profiles needed

In 2013, rhino specialists from around the world gathered in Singapore for the Sumatran Rhino Crisis Summit, a call to action based upon reports that wild populations in Malaysia had dwindled if not disappeared in recent years and that the global population probably numbered no more than 100 animals. This conclusion came as something of a shock, considering that estimates less than a decade earlier had put the population at more than double that. The truth is that the Sumatran rhino has always stymied field biologists, remaining secretive and poorly documented throughout its range. Scientific journals contain numerous accounts of researchers spending months in the forest searching in vain for this species, and the same truth applies today for those given the job of protecting it.

To give you some idea, since 2010, seven Rhino Protection Units (RPUs) – 28 men – have patrolled more than 37,000 kilometres within Indonesia’s Bukit Barisan Selatan (BBS) National Park, one of the last places on earth where Sumatran rhinos survive. That’s the equivalent of traveling back and forth from London to Moscow at least half a dozen times. During their patrols, the RPUs recorded more than 800 rhino footprints, over 300 wallows, and more than 100 dung deposits. Yet, during the same four-and-a-half years, the rangers laid eyes on living Sumatran rhinos a grand total of six times – three times in 2011 and three times in 2013. In 2010, 2012 and thus far this year they’ve seen none. Still, the data the RPUs collect allows biologists to map distributions and monitor population density.

RPUs began operating in southern Sumatra’s BBS and Way Kambas National Parks in the late 1990s and are supported by the international conservation community. They are now managed by the national NGO Yayasan Badak Indonesia (YABI). Their wildlife protection efforts have been commendable: the last documented rhino poaching in BBS occurred in 2002, the last in Way Kambas in 2006. In addition to rhinos, the RPUs help Indonesian government authorities monitor and protect other threatened species, most notable among them endangered Sumatran elephants and tigers. According to RPU reports, five elephants and two tigers have been killed by poachers in the two protected areas since 2010. More common are illegal hunting and trapping practices that target deer, small mammals and birds, captured to supply the local pet trade. Illegal fishing is also a threat, as is human encroachment into park land to plant agricultural crops, illegal wood-cutting, and the gathering of non-timber forest products. Combined, these activities negatively impact more than 50 other threatened mammals, birds, reptiles and amphibians that share the Sumatran rhino’s habitat.

What’s absolutely essential to saving Sumatran rhinos is reliable data regarding the size, sex ratios, age distributions and relatedness within remaining populations. Standardised survey methodology has been agreed upon by experts. RPUs are collecting dung samples for genetic analyses and monitoring camera traps in the parks to record wildlife movements. These new duties must be carefully balanced, however, with the RPU’s standard patrol and survey practices, which are becoming increasingly focused on concentrations of rhinos within what are best described as intensive management zones. The long-term goal is to manage Sumatran rhino populations at an annual growth rate of at least 3%, to eventually reach carrying capacity for this species in its present habitat, and ultimately to re-establish populations in regions where it formerly occurred.