We studied the recovering tiger population of India’s Rajaji National Park for 13 years, learning many lessons along the way. From rarely encountering signs of these big cats before 2004 to a thriving tiger population, we’ve documented how it is possible to recover tigers given the right circumstances. Read our press release to learn more about the study.
In the winter of 2004, I reached
Rajaji National Park (RNP) in northern India to start my master’s dissertation setting tiger and prey population baselines, just as the last of the Van Gujjar families who had chosen to resettle outside the park were leaving. Van Gujjars are pastoralists who historically practiced transhumance, moving between the sub-Himalayan foothill forests such as Rajaji in winter and the alpine meadows in summer with their livestock. During the last few decades, socio-political changes forced most of them to cease this practice, resulting in them living permanently in the foothill forests. The constant presence of their buffalo holdings led to overgrazing, with even trees lopped of their branches to feed their livestock, leaving them looking like something out of a Dr. Seuss book – long trunks devoid of foliage but for a few oddly positioned clumps of leaves.
In response to competition from livestock, populations of tiger prey species declined. Without adequate food sources, tigers became sparse, and it was rare to find signs of these big cats in the area. Despite this, I was excited to lay the baseline for monitoring how tigers and their prey would respond to this newly available disturbance-free habitat, two and a half times the size of Manhattan, from where Van Gujjar families were moving out of.
Sighting a tiger with my supervisor, Dr. Bivash Pandav, on my first day in the field was extremely encouraging.
I was also fortunate to work with Imam Hussein, a Van Gujjar field assistant, who had recently resettled with his family from the same area and knew the place like the back of his hand. He introduced me to this beautiful landscape, his former home. He was instrumental in helping me identify the best places to set-up camera traps.
Over the next three months, we photographed four females, including two showing signs of breeding, although the male remained elusive. While I gathered enough data that year to set reliable prey and tiger population baselines, the tragic fatal poisoning of one of the breeding females prompted us to return the next year to find out how this small population fared.
We returned every winter for the next 13 years to gather data, and this taught us many lessons about the recovering tiger population.
Signs of recovery in the prey and tiger populations were evident right from the start. With livestock now absent from the area,
we witnessed an increase in the recruitment of one of the principal prey spotted deer (chital). This ruminant grazer was likely outcompeted by domestic buffaloes –
a pattern that we later documented across the landscape as chital densities were significantly lower in areas of high livestock presence. Tiger numbers increased as well. Every year we photographed more tigers in the same area than the previous year, with the density increasing more than 3-fold over the study’s 13 years.
However,
much like how pumas responded to the availability of “disturbance-free” habitat in the Idaho primitive area following a ban on hunting of the species in the 1960s, in the initial years in Rajaji, very few tigers stayed in the park and we saw a high individual turnover. In this case, individuals dispersing from a nearby high-density tiger population in Corbett Tiger Reserve contributed to the influx. But, as the population neared the carrying capacity and stabilized, the survival of individuals increased and more females stayed longer (> 4 years), establishing territories and producing and raising multiple litters.
The importance of this disturbance-free space was further highlighted by numerous incidences of loss of individuals we documented during this period, just outside this protected habitat in the form of poaching, retaliatory poisoning and roadkill.
We initially documented tiger recovery in a section of RNP we call
Zone 1. In the last six years of the study, we expanded the coverage of our cameras to include two other sections of the park that differed from Zone 1 in a few key aspects:
- Zone 2, north of Zone 1, is still home to Van Gujjar families and their livestock, as they have not been offered an acceptable resettlement scheme, despite expressing their willingness to relocate.
- Zone 3 is to the west of Zone 1 but is unconnected to the other Zones due to urbanization and linear infrastructure (railway tracks, national highway and irrigation canal) along the Ganga River.
By comparing how populations performed across these sections of the park, we were able to understand the effects of human settlements and connectivity on tiger recovery. For example, In Zone 2, tiger density increased over two-fold, but survival was much lower than that witnessed in Zone 1.
On average, females remained in Zone 2 for just a quarter of the time than they did in Zone 1. They also suffered from a much lower reproduction rate as many individuals moved on from the area or succumbed to unnatural mortality (including poisoning by local pastoralists). These differences showed us that
Zone 2 acts like a “sink” that receives surplus individuals but does not provide adequate recovery of the population. This analysis made us realize that we need to dig deeper and look at survival and female land tenure (how long females remain in their territory) to confirm success.
Across the Ganga River in Zone 3, we observed only two female tigers remaining since 2012 in an area projected to be capable of supporting over 30 tigers. Although this zone presents an excellent opportunity to recover tigers,
without the possibility of individuals dispersing here naturally from the east, this sub-population is functionally extinct.
Despite repeated calls to restore this corridor and supplement tigers into this habitat, bureaucratic delays have kept this action from being implemented representing a significant failure for tiger conservation in the region.
Overall, our time in Rajaji has taught us that:
- Natural recovery of tigers is possible and can be achieved rather rapidly if a site has adequate prey. This disturbance-free habitat offers protection from poaching and conflict-induced mortality and connectivity to source populations.
- Increased density/abundance may not always indicate recovery of tiger populations in sites potentially subject to high immigration from neighboring source populations.
- Survival and female tenure serve as more robust metrics to evaluate recovery efforts.
Without the sacrifices of Imam and his community for making the choice to relocate out of Rajaji 15 years ago, we wouldn’t have what today remains
the only documented evidence of a tiger population recovering following human resettlement from a site. While human resettlement for conservation remains a contentious issue, given the potential diverse socio-economic costs on the displaced communities, this case provides a strong ecological argument for creating disturbance-free spaces where socio-politically feasible.
In this particular case, the voluntary resettlement of Van Gujjars is perceived more favorably by this community. In fact, when I carried out a survey of families still living inside forests within the larger western Terai Arc Landscape during my doctoral research,
an overwhelming majority expressed a willingness to resettle outside in return for developmental benefits such as
healthcare, education, land and permanent dwellings, veterinary care for livestock and access to markets.
Overall, this shows us that
resettlement programs, properly designed in consultation with the community, can provide clear benefits for communities and wildlife alike. While our study documents the positive effects of this conservation action on prey and tigers, it needs to be borne in mind that this was possible only because the presence of pastoralists and their livestock had demonstrable negative impacts. The effects of other forms of human presence might not be similarly adverse, but need to be carefully evaluated in each case to assess if such a drastic conservation action might result in tiger recovery.
On a more personal note, I feel incredibly privileged to have started my career with a positive story of recovery, particularly as we battle to save the remaining tiger populations and reverse the decline in tiger numbers across our core sites. The last time I visited Rajaji in 2016 was enriching as I saw tiger signs everywhere and heard about tourists' sightings very often, which was unheard of in the original years I spent on site.
Looking forward, it gives us hope that we can find more such places with the right conditions to support recoveries across the tiger’s range.
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