It was a common understanding that wild carnivores entering human settlements was due to the depletion of prey in natural habitat. But a recent study on snow leopard challenges this notion.

The findings of the study, published recently in the journal Ecology and Evolution, suggested that livestock depredation level may largely be determined by the abundances of the snow leopards and livestock in the area rather than the prey density as the killing of livestock at sites varied even at similar levels of wild prey density.

According to Gopal Khanal, one of the researchers, the study was conducted to better understand what drives livestock depredation by the snow leopard (Panthera uncial).

The study compared whether the extent of livestock killing by snow leopards would differ in relation to densities of wild prey, livestock and snow leopards at two sites—Upper and Lower Dolpa—inside Shey Phoksundo National Park in Nepal.

“It is commonly hypothesised that lack of wild prey causes snow leopards to turn to livestock. However, it can be the other way around as well: high wild prey density may increase snow leopard density and hence more livestock depredation,” Khanal told the Post. “What we found was that even when wild prey density was the same across two sites, the sites with high livestock and snow leopard density had higher livestock predation.”

The researchers relied on the camera trap method to estimate snow leopard density and double‐observer surveys to estimate the density of snow leopards’ main prey species—the blue sheep (Pseudois nayaur). They also conducted household surveys to estimate livestock population and number of livestock killed by snow leopards in both Upper and Lower Dolpa.

The total livestock population of Upper Dolpa was approximately 13,000 while that of Lower Dolpa was approximately 1,600. The household survey found that a total of 487 livestock were reportedly lost to snow leopards in Upper Dolpa and 30 livestock in Lower Dolpa in the year of 2017. Goats and sheep accounted for 90 percent of the cattle loss to snow leopards.

According to the livestock survey findings, the proportion of livestock lost per household was seven times higher in Upper Dolpa in comparison to Lower Dolpa.

“We found that Upper Dolpa with higher snow leopard density and livestock density also had high livestock depredation than Lower Dolpa which has both lower snow leopard and livestock density,” said Khanal, who is also an assistant conservation officer at the Shey Phoksundo National Park.

Upper Dolpa had higher snow leopard density (2.51 snow leopards per 100 sq km) and higher livestock density (17.21 livestock per sq km) compared to Lower Dolpa (1.21 snow leopards per 100 sq km and 4.5 livestock per sq km).

However, the blue sheep density was similar—1.81 and 1.57 animals per sq km— in Upper and Lower Dolpa.

The study concluded that the combined influence of higher snow leopard and livestock density appeared to have resulted in greater livestock predation in Upper Dolpa, suggesting that an increase in livestock population and/or snow leopard population could potentially intensify predation.

“Our finding suggests that livestock depredation may well be largely determined by the predator (snow leopard density) and livestock density,” said Khanal. “The general hypothesis is that lack of wild prey availability leads to higher livestock depredation. It turns out this is not always true.”

A similar study conducted in multiple sites in India and Mongolia had found that snow leopards in Asia would still prey extensively on livestock even when wild prey is available in high numbers. Another study, which had analysed 347 scat samples, collected across 5,000 sq km in the central Himalayas in Nepal, had concluded that more than a quarter of the animals consumed by snow leopards were livestock.

According to researchers, there are a myriad of factors responsible for livestock depredation like the ecology of snow leopards, livestock husbandry and herding practices, landscape characteristics, wild prey availability, habitat type and structure, behavioural characteristics of the predator and predator abundance.

“The proportion of small-bodied livestock (goat/sheep) is also higher in Upper Dolpa. The higher proportion of small-bodied livestock and total livestock in the region also suggests that livestock grazing there is more sparse, elevating the risk of livestock being attacked while grazing in rangelands,” said Khanal.

“Herders in Upper Dolpa keep their livestock for more days in their pastures. These factors also have influenced livestock loss patterns in Upper Dolpa and Lower Dolpa,” Khanal added. “We found that herders owning a higher number of small-bodied livestock and those grazing a higher number of days in the pastures were likely to lose more livestock overall.”

Findings from such studies and understanding the interplay between predator, wild prey, and livestock density is essential for identifying mitigation measures for minimising conflict between the local communities and snow leopards.

The snow leopard is listed as Vulnerable in the IUCN Red List of Threatened Species and occurs in 12 countries across the Himalaya and high mountains of Central Asia. Fewer than 4,000 adult snow leopards are believed to occur in the wild as they continue to face threats due to habitat loss, poaching and the impact of climate change.

Snow leopards prefer to prey on herbivores, such as blue sheep, Argali sheep and ibex. But in many areas, as in Upper and Lower Dolpa, snow leopards also prey on livestock, cattle, yak and horses, bringing them into conflict with herders for livestock depredation and exposing them at the risk of retaliation killing—a threat of wildlife conservation.

A study on understanding carnivore killing behaviour based on the motivations for tiger killing in the Sundarbans, Bangladesh, has shown that livestock depredation by wild animals disturbs the livelihoods of often marginalised communities, eroding their human tolerance of carnivores. The same lesson applies for the conservation of snow leopards from retaliation killings which may arise from livestock depredation of Himalayan communities.

“Human-snow leopard conflict over livestock depredation is the most pervasive threat to snow leopards across its range in Central Asia and the Himalayas. Livestock production or population is predicted to increase in some areas of its range to meet the demand for cashmere,” said Khanal. “Such an increase in livestock production may depress wild prey population via fodder competition reducing the carrying capacity for the snow leopard population.”

However, efforts to recover the snow leopard population may have consequences for local economies of herder communities as increasing snow leopard population also mean increased risk for livestock predation, according to Khanal.

“Mitigating livestock depredation and hence human-snow leopard conflict and retaliatory killing of snow leopards require both measures to reduce/prevent livestock loss via improved herding practices, like predator-proof corrals, and measures to offset the economic loss incurred due to livestock loss via compensation payments,” Khanal told the Post.

In recent years, the Nepal government has been focusing on managing human-snow leopard conflicts. The Shey Phoksundo National Park has been providing relief funds to local communities to compensate for the livestock loss.

“This is because some level of livestock depredation may be inevitable, and livestock may actually be contributing to sustaining some proportion of snow leopard population as shown by studies in other areas,” said Khanal.