- Tigers need large areas to survive but if well protected, populations can rebound quickly. Nepal and India experienced 61% and 31% increases, respectively, in their tiger populations recently thanks to better habitat protection and anti-poaching efforts.
- The global tiger population now stands at fewer than 3,500; the goal is to double by 2022
- Scientists found less than 8 percent (79,600 km2) of global tiger habitat was lost between 2001 and 2014, enough habitat to have supported about 400 tigers.
- First major study to use high and medium-resolution satellite data from Global Forest Watch to examine impact of forest loss on tiger populations.
New forest habitat analysis findings provide hope for the survival of tigers in the wild.
Satellite imagery analysis has shown that enough forest habitat still remains to bring the tiger back from the brink of extinction. A new study found that forest loss, while substantial, was lower than expected in tiger habitats, suggesting there is more than enough habitat remaining to achieve the international commitment of doubling the wild tiger population by 2022 (an initiative known as “Tx2”) with additional conservation investment.
With roughly 3,200 wild tigers remaining in the world, high-level government officials of the 13 tiger-range countries met in 2010 and committed to work to double the wild tiger population by 2022. To achieve this goal, states must maintain and even restore tigers’ natural habitat; the meeting participants identified 76 Tiger Conservation Landscapes (TCLs)—areas across Asia with adequate food and space to allow long-term survival of this wide-ranging species—in which to focus their efforts.
Forest is a key habitat for tigers, and tiger survival depends on preventing further habitat fragmentation and loss. However, monitoring tiger habitat across landscapes that often extend over multiple jurisdictions has been a major challenge to the wildlife managers on the ground.
The multi-institutional study, “Tracking changes and preventing loss in critical tiger habitat,” used newly available tools and data from Google Earth Engine (GEE), Global Forest Watch (GFW) and University of Maryland to analyze habitat conditions in the 76 TCLs. The analysis quantified and assessed forest cover and how it has increased or decreased between 2001 and 2014 within the 76 TCLs
The new study is the first to use these tools to systematically assess the habitat status of this iconic big cat, which increasingly depends on remaining forests as people encroach and alter grasslands and other tiger habitats. The free access to annually updated global tree cover data and tools to analyze tree cover loss and gain provided by GFW and GEE made the analysis both possible and repeatable by range-state authorities and the public. You can find the TCLs in the Conservation section of GFW and even conduct your own analysis of forest condition in any area within the 76 landscapes.
Tigers on the edge
The analysis showed that less than 8% (nearly 79,000 km2 or 30,000 mi2) of global tiger habitat was lost from 2001-2014. This rate of forest loss was lower than anticipated, given that much of tiger habitat is located in fast-growing rural economies and often faces severe pressure from high human population densities and industrial agriculture.
Nevertheless, the study also confirmed the precariousness of the species’ survival. The researchers estimate that forest clearing since 2001 resulted in the loss of habitat that could have supported an estimated 400 tigers. This is potentially devastating, considering the small size of the global tiger population. Furthermore, the study did not consider the deleterious effects of poaching and prey loss within these landscapes, which compound the tiger’s difficulties.
“It is remarkable and unexpected that tiger habitat has been relatively well-preserved over this 14-year period,” said Anup Joshi, Research Associate at the University of Minnesota and lead author. “It is not a sign that we are in the clear yet, but it does show us that tigers can potentially recover from the edge of extinction if we make the right forest management choices. We are seeing this already in areas like the border between Nepal and India, where forest cover is recovering with the help of communities and tigers are coming back in a big way.”
The vast majority (98%) of tiger forest habitat loss occurred within just 10 of the 76 TCLs, mostly driven by the conversion of natural forest to plantations for agricultural commodities such as palm oil. In fact, the TCLs with the highest percentage of forest clearing were in areas of Malaysia and Indonesia with heavy oil palm development. Six of the 10 TCLs with the highest percentage of forest loss overlap with oil palm plantations.
Information leads to action
Joshi explained that by mapping forest loss and gain in the TCLs and critical zones within the TCLs, such as core breeding areas and corridors, the study “provides actionable information to wildlife and conservation agencies to support tiger recovery globally.” The spatially explicit information on forest loss or recovery can help direct conservation efforts to specific areas for enhanced protection, restoration, tiger reintroduction and other management actions. It can also enable an analysis of broad-scale trends in habitat change.
“The ability to measure forest change within endangered species habitat across the globe is a huge step forward for conservation and remote sensing,” said Crystal Davis, Director of Global Forest Watch at the World Resources Institute. “Now it is time to use the data to take action. If we can use that information to respond faster to threats, we can ensure that tigers will survive for future generations.”
The GFW technology enables on-the-ground action by providing free monthly and in some cases weekly tree cover loss alerts; these alerts can empower park rangers and communities to monitor and protect tiger forest habitat, even at the finest scale of a single forest corridor used by a dispersing male tiger. Field managers in tiger range countries can request to receive alerts when large-scale forest loss occurs within or outside their jurisdictions, to allow them to intervene quickly to prevent further habitat loss. Any interested person can sign up to receive alerts of tree cover loss in a selected area, such as a country, protected area or forestry concession zone.
To maintain tigers in the wild, the conservation community and range-state leaders must remain vigilant over broad scales as well. Among key tiger range states, as much as $750 billion annually is expected to be invested in infrastructure projects over the next decade. Even if only a fraction of this investment finances new road construction within tiger landscapes, the greater human presence associated with new road networks, including increased hunting and land clearing, will further fragment remaining forest.
“After decades of working in tiger conservation, it is great to have some encouraging news for once,” said Eric Dinerstein, Director of the Biodiversity and Wildlife Solutions Program at RESOLVE and a Senior Fellow at WRI. “But illegal hunting of both tigers and prey can result in ‘empty forests’ without enough food or shelter to support large predators like tigers. Measuring and combatting this sort of forest impoverishment and its effects will be essential. It complements our efforts to identify habitat poaching in this study.”
Most encouraging was that loss was less than expected in the 51 tiger reserves that serve as source sites in the priority landscapes. This suggests that if future habitat loss is prevented, the tiger recovery now underway in some range states will accelerate. In these promising locales of enhanced protection, a population doubling by 2022 could be attainable.
Disclosure: The author and several additional RESOLVE and World Resources Institute staff are authors of this paper.