Malayan Flying Fox, Singapore Zoo, May 2017. (Used under Creative Commons license) Flickr/Jack Herman

Increasing demand for food and traditional medicines, multiplying local wars and conflicts, an expanding legal and illegal market trade have exacerbated the wildlife crisis in recent years, damaging ecosystems and driving many species to the verge of extinction.

Defined by scientists as the “widespread unsustainable exploitation of wildlife,” the situation is of particular concern in the rural tropics, where biodiversity is also under threat as natural habitats shrink and populations grow. Human-wildlife interactions have led to pathogen exchange and triggered such recent zoonotic infectious disease outbreaks as Severe Acute Respiratory Syndrome (SARS), Ebola and COVID-19.

Subsistence hunter-gatherer societies have been active in the tropics for more than 40,000 years, but over the past century as hunting methods have become more efficient, so has the capacity to capture larger numbers of animals and other wildlife.

A multi-billion dollar industry, the illegal wildlife trade for meat and medicines poses  a major threat to forest ecosystems, despite the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES), due to difficulties with enforcement, say scientists with the Center for International Forestry Research (CIFOR) in a recent research paper published in the Annual Review of Environment and Resources.

“Wildlife harvesting has reached unsustainable levels, partly because of conservation initiatives historically developed to address elitist interests, rather than the interests of forest-dependent rural people, said Robert Nasi, director general of CIFOR and managing director of World Agroforestry (ICRAF), one of the authors of the study.

The key to addressing the challenges is to develop a multi-disciplinary strategy, which embraces political, socioeconomic factors and scientific knowhow while bringing government, non-government, national and international organizations to the table to discuss the path forward.

“Change will only occur after public education campaigns and conservation institutions are strengthened, but we need to do more than that,” Nasi said. “We also need to develop sustainable agriculture initiatives to meet food security needs and ensure that laws on wildlife management are improved and enforced.”

As part of their survey, the scientists investigated the harvesting of wildlife products for food and medicine in tropical Africa, the Americas and in Asia. They explored the complex drivers of wildlife harvesting for bushmeat and traditional medicine, the consequences for biodiversity, the environment and human populations.

Over-harvesting of wild meat can threaten food security if in-demand species are hunted at too high a rate. The impact is enormous, since at least 300 million of the poorest people in the world are dependent on forests for their livelihoods and 90 percent of the world’s poorest people depend largely on forests for their livelihoods. In a comparison of two main moist-tropical regions — the Amazon and Congo basins — scientists learned that more than 5 million tons of wild meat feed millions of local people in neotropical and Afrotropical forests each year.

“It’s likely that many forest mammals will become extinct soon and that protein malnutrition will increase if nutritional security in these regions aren’t urgently addressed,” Nasi said. “Unless there is a drastic change to make wildlife exploitation — including for non-essential ‘luxury’ products — more sustainable, the tropics will certainly lose most of its iconic species and many others in the coming years.”

A range of hunting-related activities harmful to the natural balance of ecosystems also exacerbate food insecurity, the paper states.

“The loss of some animal species through overhunting can limit the potential for forests to regenerate,” Nasi said. “It’s caused lasting changes in tree populations, spatial distribution of trees, growth and dynamics, resulting in a decline in local tree diversity over time. For example, large fruit bats and birds distribute seeds in their droppings over long distances and should be protected from hunting in tropical East Asia.”

The large flying fox in Borneo once played a key role in pollination in several Malaysian states but because of unsustainable hunting practices, no longer does, raising concerns about the future of plant species and growth. The flying fox species itself is also at risk and could present a public health danger as it has the potential to spread viruses due to closer and more frequent contact with humans as its habitat is degraded.

In Vietnam, the Javan rhinoceros was declared extinct in 2010 mainly due to poaching for global markets and weak law enforcement. In Africa, particularly in savanna biomes, the impact of the wildlife trade varies from edge effects surrounding protected areas to staggered degrees of species decline, often due to inadequate anti-poaching enforcement.

“Huge improvements to existing infrastructure, particularly roads, has facilitated wildlife trade across the tropics,” Nasi said. “These improvements have made forested areas more accessible, creating opportunities for rural areas to trade wildlife products with distant urban markets.”

Road expansion has led to increased hunting activities, putting tropical wildlife in both Africa and the Amazon at risk. Research shows that in the Yasuni Biosphere Reserve in Ecuador, roads led to a twofold increase of the extraction area, while in Amazonia roads in protected areas undermine wildlife populations, threatening the livelihoods of Indigenous Peoples.

Forest dwellers hunt and trap bushmeat for dietary and nutritional purposes, but pressures on bird and animal populations are further compromised because many people kill more than they need, also selling it for income. In a survey of 20 tropical and subtropical countries in Asia, Latin America and sub-Saharan Africa, scientists learned that 39 percent of households hunt, 87 percent consume what they kill, earning on average only 2 percent of income from bushmeat.

“Urbanization has led to rising demand for wildlife beyond tropical rural regions, placing immense pressure on regional biodiversity and human wellbeing, exacerbating potential health risks of zoonotic diseases,” Nasi said, adding that more than 300 terrestrial mammal species are threatened with extinction because of an increase in bushmeat hunting to supply urban demand.

The review also notes the general lack of reliable data on wild meat harvests. Scientists suggest the use of remote monitoring systems to help aggregate information and provide a better picture of where and how hunting is occurring. Wild food should be included in official government statistics to ensure that activities are monitored so that strategies to create more sustainable hunting practices can be developed.

“Empty forests” in the tropics — forests in which large animals have mostly been killed off or extracted — signal the need to improve management and enforcement of tropical protected-area networks. In addition to conservation areas, the scientists recommend designing relevant landscapes with various zones, including hunting, no take and safe.

“Adding recovery zones could help bring back populations of animals in areas where overhunting has occurred,” Nasi said. “This has been effectively implemented in Thailand’s Thung Yai Wildlife Sanctuary, where reports indicate that population recovery of ungulates increased the prey base for endangered tigers.”

Participatory land management involving Indigenous and local communities should also be better leveraged to conserve wildlife. Yet, over time, changing tastes and demands can lead to shifts in the type of game hunted, creating less sustainable dynamics, so this option is not necessarily a “silver bullet” solution, Nasi said.

Demand for wild meat can be reduced by making alternative sources of protein available. That could mean creating farms for some wildlife species or encouraging the consumption of other nonconventional animals, such as rodents, to alleviate pressure on species at risk.

Wildlife is also harvested for traditional medicine, more than often unsustainably. Primate-use in folk medicine is linked to magic-religious rituals and remedies.

In Africa, many cultures use animal parts for traditional and religious practices. In semi-arid, north-eastern Brazil, animals are used as amulets and charms in rituals and ceremonies. Throughout Asia, rhinos, tigers, elephants, pangolins and turtles are among the animals culled for medicinal use. In Indonesia’s East Kalimantan province, the number of hose’s langurs plummeted over a seven-year period due to overhunting for bezoar stones.

“While demand reduction is likely to be the most challenging solution due to cultural customs and social status associated with many traditional medicine products, certification systems and synthetic alternatives are potential solutions,” Nasi said.

Solutions could also include stopping illegal trade, increasing public awareness and advocating sustainable wildlife use and consumption.

Urban demand is another significant contributor to unsustainable harvests and wildlife depletion in forests. In some areas, bushmeat consumption is considered a status symbol.

However, the urban attraction to bushmeat may not be so appealing as the world struggles to contain the COVID-19 pandemic, which is widely believed to have zoonotic origins in bats and to have passed through another animal, possibly a pangolin or a dog, before jumping to humans in a wet market in Wuhan, China. The HIV/AIDS pandemic is hypothesized to have emerged from bushmeat hunting in Africa before spreading worldwide.

A study conducted after the 2003 SARS epidemic revealed that post-epidemic wildmeat consumption may be reduced after a related disease outbreak. When illegal wildlife and bushmeat are sold in legal markets where quarantine and supervisory regulations are poorly enforced, the convergence of wild and domestic animals allows the exchange of pathogens among diverse species and a spillover from wild hosts to humans.

“High volumes of wildlife, high risk taxa for zoonoses and poor biosafety in markets increase the potential for pathogen presence and transmission,” Nasi said.

“There’s no quick fix,” Nasi said. “Due to the multi-faceted nature of the crisis, we must work at the interface of rural livelihood improvement and conservation of natural forests to determine how the goals of poverty alleviation and forest conservation can be optimally aligned.”