In January 2024, I returned to Aceh to find a far different project than the one I’d left behind. It had been 46 months since my original Fulbright US Scholar award was cut short by the pandemic, and my eagerness to get back could not be understated.
While I was away, a core team of rangers and other collaborators had managed to maintain some tiger research and conservation activities. This team was comprised of individuals from local universities and communities, NGOs, and government agencies. Despite their progress in my absence, I was worried that our study area had become overrun by hunters, poachers, and unpermitted loggers. I was fully aware that the rangers were already stretched too thin across the landscape during our first year of work. Lack of constant vigilance could spell doom for the tigers in our study area. What would happen when patrols stopped entirely?
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Among large carnivores worldwide, the plight of the tiger is unparalleled; no other terrestrial apex predator has suffered a decline so severe over an area so large. Once occurring across most of the Asian continent, from Turkey in the west to Russia in the east, tigers are now found in only a tiny sliver of their vast historic distribution. By the end of the 20th century, tigers were obliterated from Southwest and Central Asia, two Indonesian islands (Java and Bali) and most of Southeast and Eastern Asia.
More than any other big cat, the case of the tiger embodies the insidious impacts of habitat fragmentation, a process whereby large and contiguous habitats are divided into smaller, isolated patches surrounded by human-modified lands. When forests are fragmented by roads, settlements, and other human infrastructure, tigers are forced into scattered habitats and cut off from other populations. This isolation erodes genetic diversity and increases accessibility for poachers. It is a chronic process that induces ecosystems–and tiger populations–into a state of decay.
In their fragmented habitats, tigers are victims of an onslaught of intense threats experienced by only the world’s most severely imperiled species. Despite considerable variation in these threats, in form and intensity, across the species’ distribution, the dangers remain relatively constant: Advancing deforestation, burgeoning human populations, overhunting of prey, and, most pressingly, relentless persecution by poachers.
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Pre-Covid, our task was to assess the conservation status of the tiger population in the rainforests of central Aceh. At the time of my first Fulbright US Scholar award in 2019, fundamental data on tiger distribution and the presence of breeding females were nonexistent. Tiger population trends were anyone’s guess.
Post-Covid, one of the first steps to reinitiating on-the-ground research was settling on a study area that would a) serve as a logistically feasible setting for our camera-trap sampling polygon, b) accurately represent the wider landscape of tiger habitats in Aceh, and c) facilitate rapid-response to human-tiger conflict. That area became the rugged mountains and adjacent foothills of central Aceh, in a region known as the Gayo Highlands.
Spanning 11,460 km², the Gayo Highlands (Fig. 1) comprise approximately 21% of Aceh’s land area and 2.5% of Sumatra. Of Sumatra’s six peaks over 3,000 meters, three are in the Gayo Highlands–Gunung Leuser, Gunung Kemiri, and Gunung Bandahara. Tigers in these highlands have been insulated, to some extent, from the onslaught of threats facing the species at sites of greater topographic and cultural homogeneity at lower elevations.
Although the best available data indicate that most of Aceh’s tigers occur in the provinces’ mountains and foothills, their presence there does not necessarily signify that the habitat therein is optimal or preferred. Animals confined to suboptimal habitats can be recognized as “refugee species” when their historical ranges have contracted to the extent that the species is restricted to limited, less diverse habitats. This supports the view that tigers in the Gayo Highlands may have retreated from lowland areas occupied by more humans, one of the criteria for designation as a refuge species.
Nonetheless, our three-year camera-trap dataset, complemented by intriguing evidence from other studies elsewhere in Asia, is challenging prevailing ideas about mountainous regions representing inadequate tiger habitat (Figs. 2, 3).
Fig. 1. The Gayo Highlands in Aceh, Sumatra. Photo credit: Joe Figel.
Inaccessibility is the best form of natural protection for tigers. While Chinese and Vietnamese markets have built up ecologically ruinous empires whose tentacles have spread well beyond their borders, their influence has been slower to penetrate Sumatra’s highland forests. The Gayo Highlands, for example, are buffered by the Malacca Strait and the Andaman Sea and separated ~2,000 km from the biggest markets of demand for illegally traded wildlife parts, including tiger skins and bones.
But if the catastrophic losses of tigers from Indochina are any lesson, it is only a matter of time before East Asia’s wave of demand reaches Aceh’s mountains. For this reason, the identification and training of new rangers is my top priority during the final stages of my Fulbright award. Tiger conservation in the Gayo Highlands will face insurmountable obstacles if the ranger network is not fortified.
Fig. 2. A male tiger photographed in the Gayo Highlands. The flash in the background is from a remotely triggered camera, which project rangers install in pairs in the study area.
Ranger patrols, when regularly conducted, send a strong message to poachers that tigers are valued and their habitats are under surveillance (Fig. 4). The common traits of these dedicated individuals include physical fitness, the ability to use standard expedition instruments such as GPS units, soil test kits,and camera-traps and, most importantly, knowledge of, and passion for, the forest. The rangers also need grit to withstand the inevitable hardships of one-two-week expeditions in rugged mountains where torrential downpours turn trails into small rivers and flood poorly selected campsites.
Fig. 3. A wild juvenile tiger in the Gayo Highlands. Photo credit: Joe Figel, Universitas Gajah Putih, BKSDA-Aceh, Pancacita, Leuser International Foundation.
Fig. 4. Breeding female tigers need safe, secure habitats to raise cubs. Here, in an area infrequently patrolled by rangers, a tigress and her two cubs are in dangerously close proximity to loggers on the same trail. Photo credit: Joe Figel, Leuser International Foundation, BKSDA-Aceh, Pancacita, Memphis Zoological Society, Fulbright Indonesia.
My next story will detail the activities and accomplishments of these ranger expeditions.
1 Figel et al. 2021. Malignant snare traps threaten an irreplaceable megafauna community. Tropical Conservation Science 14:1940082921989187.
2 Goodrich J, et al. 2022. Panthera tigris. The IUCN Red List of Threatened Species 2022: e.T15955A214862019.
3 Kartika E. 2023. Multiple anthropogenic pressures: Challenges for tiger conservation. PhD dissertation, Wageningen University, Netherlands.
4 Kerley GIH, et al. 2012. Conservation implications of the refugee species concept and the European bison: King of the forest or refugee in a marginal habitat? Ecography 35:519–529.
5 Tempa T, et al. 2019. The spatial distribution and population density of tigers in mountainous terrain of Bhutan. Biological Conservation 238:108192.
6 Rasphone A, et al. 2019. Documenting the demise of tiger and leopard, and the status of other carnivores and prey, in Lao PDR’s most prized protected area: Nam Et-Phou Louey. Global Ecology and Conservation 20:e00766.
