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Big mammals are at risk in the world’s poorest countries, even within parks

Pangolin rescued from the wildlife trade in Cambodia. Photo by Rhett A. Butler.

  • Forty years of global conservation research reveals that mammal populations are declining due to hunting in poor countries and within preserved areas, especially in Africa.
  • Large mammals are particularly vulnerable, since their slow growth and reproduction rates make it harder for them to bounce back from poaching.
  • In Asia, protected areas with tighter enforcement actually have higher rates of population loss, likely because the most sought-after species only exist within these strict enclaves.

Poaching is a pervasive global problem, and iconic mammals like elephants and rhinos are hit hard by illegal hunting. This is especially true in the world’s poorest countries and within protected areas, researchers reported recently in PLOS ONE.

Protected areas, such as national parks and wildlife refuges, are “the cornerstone of biodiversity conservation,” the researchers write. Yet many countries lack the resources to properly manage these sanctuaries. And in poor countries, people turn to the illegal wildlife trade out of financial necessity.

Spatial distribution of research on illegal hunting of mammals in 155 PAs from 48 countries over four decades as collated in the literature. Black dots correspond to the center of a protected area where research for the reviewed papers was conducted. Courtesy of Rija et al (2020).

In the new study, biologists surveyed 40 years of conservation research literature, comprising 155 protected areas in 48 countries. The published papers included 294 different mammal species.

The bottom line was clear: “Across the globe, mammals in protected areas are at great risk of decline,” said Alfan Rija, an ecologist at Sokoine University of Agriculture in Tanzania and lead author of the paper. “And we found that protected areas of Africa are highly at risk of losing species.”

Big mammals like elephants, Earth’s largest land-dwellers, are especially vulnerable. While these animals provide essential functions to an area’s ecology, such as dispersing seeds in their dung, they grow slowly and reproduce infrequently. For example, the African savannah elephant (Loxodonta africana) famously gestates for nearly 20 months before giving birth.

Elephant calf in Africa. Elephants are targeted for their tusks Photo by Rhett A. Butler.

These aspects of mammalian biology are “the most important driver for these large mammals to decline, given the high pressure of illegal uptake,” Rija told Mongabay. Populations simply cannot “catch up” to counteract the hits they take from poaching, he noted.

The study also accounted for differences in “strictness” of protection, according to categories set by the IUCN. In almost all cases, stricter protection meant mammal populations were less likely to face losses. But in Asia, the authors found the greatest declines from illegal hunting occurred in the most strictly managed areas, where human use is supposed to be limited and tightly controlled.

“There is a high illegal market of wildlife body parts for traditional medicine,” Rija said of some areas in Asia. Lucrative species like tiger (Panthera tigris), sun bear (Helarctos malayanus) and pangolin (Manis) usually only reside within the tightest enclaves.

Tigers are under pressure for the wildlife trade. Photo by Rhett A. Butler.

“We’ve lost more or less all wild, larger mammals outside of protected areas,” said Jonas Geldmann, an ecologist at the University of Copenhagen, Denmark, who was not involved with the study. “And in particular, stricter protected areas are where a lot of wildlife is left.” High illicit demand for these animals pushes poachers into these areas, despite their status as being more secure, Geldmann told Mongabay.

Although the study is limited in scope as a literature review, Geldmann noted, it confirms that poaching is an economic issue in Africa.

Tackling development in Africa is essential to address overhunting, Rija said. “If people are actually going to poach animals, they probably don’t have alternatives. The first important thing is to facilitate their development, to give opportunities for these kinds of communities so they don’t put pressure directly on wildlife,” said Rija, who conducted the work while earning his Ph.D. at the University of York, U.K.

In many cases, there is possibility and promise in pairing conservation projects with economic development efforts, Rija believes. For example, sponsoring ecotourism programs in communities could boost the livelihoods of residents.

“That can help local people actually generate their own income from wildlife,” Rija said. “If people are equipped with, for example, a financial loan to start their own wildlife farms, ranches or zoos and do that commercially, they could actually improve their local economies and incline away from poaching.”

Pangolin rescued from the wildlife trade in Cambodia. Other research has indicated that pangolins are the most trafficked animal in the world. Photo by Rhett A. Butler.


Rija, A., Critchlow, R., Thomas, C., & Beale, C. (2020). Global extent and drivers of mammal population declines in protected areas under illegal hunting pressure. PLOS ONE 15(8). (

Tess Joosse (@tessjoosse) is a graduate student in the Science Communication program at the University of California, Santa Cruz. Other Mongabay stories produced by UCSC students can be found here.