NAIROBI ― For the last two decades, Matambire Mgemaa, a pastoralist in southern Tanzania in the environs of Ruaha National Park, nighttime has meant staying vigilant to protect his goats, sheep and cattle from lion and leopard attacks in an area that is home to 10% of the world’s wild lions.

“This [is] a hectic task. … I [spend] the whole day with the livestock outside, making sure they are fed, but I cannot sleep at night because I will lose them,” Mgemaa says.

Because of their excellent night vision, which enables them to hunt more successfully in low light, lions, leopards and hyenas are mostly active at night, the time for their dinner.

But a new study published this month in Conservation Letters has found that multiple medium- or high-density fortified enclosures in a neighborhood can shield livestock from the marauding carnivores, as they avoid such areas. The researchers reveal that such fortified pens not only help those who have them reduce attacks on their livestock but also those of their neighbors.

In southern Tanzania, a key landscape for large carnivore conservation, agropastoralists keep livestock in fenced compounds at night and herd them to community grazing lands during the day.

On average, Mgemaa and his neighbors have lost two of their livestock weekly to the carnivores, but the attacks have drastically reduced. Early in 2024, Mgemaa constructed a chain-link corral to prevent his livestock from being raided in the night by carnivores.

Winston Mtandamo, field operations manager at conservation NGO, Lion Landscapes in Tanzania, says that attacks from carnivores, especially lions and hyenas, on livestock for pastoralists in Ruaha, Tanzania, increased in the last decade.

“During the nights, the carnivores were attacking the pastoralists’ bomas [enclosures] and feeding on their livestock. We realized that most of the livestock [shelters] were fenced with weak, short plant materials that the carnivores could easily pull down or jump over and access the animals. We suggested that farmers try fortified fences using chain link with tall wooden or metallic posts,” Mtandamo says.

Conservationists from Lion Landscapes are working with pastoralists to construct fortified corrals to protect livestock and vulnerable carnivore species.

When a pastoralist constructs a corral to protect his farm, the researchers found that, surprisingly, instead of dining on easier meals next door and negatively impacting neighbors who don’t have fortified enclosures, predators seem to completely avoid neighborhoods with corrals built from chain-link fencing. It is more effective than traditional African boma fences made of short, thorny bushes.

The study’s lead author, Jonathan Salerno, an assistant professor from Colorado State University’s Human Dimensions of Natural Resources Department, tells Mongabay the more enclosures in an area, the more protection for even neighbors who have not constructed the fortified pens.

The neighborhood with three or four enclosures presents the carnivore with a more complicated task to pull a goat or sheep out of the fortified enclosures, giving the predators “too much work,” he says. “The fences reduce the availability; the nighttime livestock buffet is simply less accessible and attractive. … Although we don’t have data on carnivore behavior, the most likely explanation is that multiple fortified enclosures in a neighborhood simply increase the time, effort and risk it takes to hunt in the area, so carnivores simply avoid neighborhoods with medium- or high-density fortifications,” Salerno says.

The researchers examined 25,000 monthly reports from livestock keepers collected by Lion Landscapes that revealed households neighboring those with chain-link pens also reported fewer carnivore attacks on their livestock.

Mgemaa is happy that he is unlikely to incur losses to his livestock, his sole source of income and livelihood. “It is like the tall chain-link scares them away. They don’t even bother coming. In the few instances when they come, they don’t even attempt to attack the fence but walk away,” Mgemaa tells Mongabay in a telephone interview.

According to the researchers, the findings are the first to demonstrate a beneficial spillover effect from a strategy to reduce conflict with large carnivores, which play an important role in ecosystems. The researchers say that losing apex predators can cause ripple effects that disrupt the food web and impact environmental health.

In a different study published in Conservation Science and Practice in January this year, Ana Grau, research associate at Lion Landscapes, Salerno and colleagues demonstrated that chain-link corrals reduced predation on cattle, goats and sheep in an area surrounding Ruaha National Park. The study used monthly data from 758 livestock-keeping households from 2010 to 2016, finding that chain-link corrals were 94% effective at reducing the risk of predation in the short term and 60% effective in the long term.

“We know that fortified enclosures are effective at reducing predation on livestock, and they can be one of [the] multiple useful tools to reduce conflicts in areas where people graze livestock near and overlapping carnivore ranges,” Salerno explains to Mongabay. “But evaluating the effectiveness of just fortified enclosures ignores what’s going on in the surrounding neighborhood of unfortified households. The potential for spillover effects from human-wildlife conflict mitigation efforts is a question that goes unanswered in most systems where the work is ongoing — does conflict mitigation just push wildlife to nearby households to cause conflict there? If that’s the case, if spillover effects occur, then there may be no net reduction in conflict and its harmful outcomes for wildlife and people.”

Conservation Letters study co-author, Kevin Crooks, who is director of the CSU Center for Human-Carnivore Coexistence, says the study shows that proactive, nonlethal tools can be effective to prevent livestock predation by carnivores, benefiting not just the target household but potentially neighboring households as well.

According to Mtandamo, pastoralists in the region incur significant economic losses annually to predators. “With these fences, the lions, leopards and hyenas get frustrated and tend to avoid coming to the area where farmers have built fortified pens. When we suggested this, some of the farmers did not initially agree, but many are now constructing the fortified enclosures. The pastoralists can now get enough rest at night and work during the day,” Mtandamo tells Mongabay.

Lion Landscapes subsidized 75% of the cost of construction for the farmers who chose to use the fortified enclosures. The study shows that after five years, the benefits from preventing livestock deaths were 3-7 times greater than the expenses incurred by the farmers to construct fortified pens.

The researchers urge for an understanding of the interactions between predators and people, as such dynamics can help guide effective use of conservation resources and support better outcomes for people, livestock and threatened species.

Joseph Kaduma, the study’s co-author and a research manager from Lion Landscapes, says the study provides scientific evidence on how fortified enclosures could foster peaceful coexistence between humans and carnivores. “By demonstrating how nonlethal methods can benefit both people and wildlife, the study offers practical conservation solutions that can be scaled to other regions facing similar conflicts worldwide.”

Salerno argues that fencing a park as vast as Ruaha could not be cost-effective and would pose negative ecological consequences by isolating wildlife, which could spur conflict between communities and conservation interests in the region.

He urges conservation practitioners to allocate resources to strategically place fortified enclosures, or conflict mitigation tools generally, by understanding their impacts in surrounding neighborhoods and areas, as they will provide a protective effect for unfortified neighbors.

“We also need to acknowledge and understand spatial and temporal spillover effects of conservation strategies more broadly. Gathering and maintaining these data can be costly, but such monitoring is essential if we’re going to consider conservation efforts and their impacts across scales, which is necessary, especially in the complex systems that typically shape human-wildlife conflicts,” Salerno says.

Banner image: A lion at Ruaha National Park. Image courtesy of Richard Mortel via Wikimedia Commons (CC-BY-2.0)

Can cattle and wildlife co-exist in the Maasai Mara? A controversial study says yes

Citations:

Salerno, J., Warrier, R., Breck, S. W., Carter, N. H., Berger, J., Barrett, B. J., … Crooks, K. R. (2025). Beneficial spillover effects of Antipredation interventions support human–carnivore coexistence. Conservation Letters, 18(2). doi:10.1111/conl.13085

Grau, A., Salerno, J., Hilton, T., Lowasa, A., Cotterill, A., & Dickman, A. J. (2025). Evaluating the effectiveness of fortified livestock enclosures as a human‐carnivore conflict mitigation tool in Tanzania’s Ruaha landscape. Conservation Science and Practice, 7(2). doi:10.1111/csp2.13299