Billions of people worldwide rely on around 50,000 species of wild plants and animals for food, energy, medicines and income, according to a major intergovernmental report prepared by dozens of scientists. Although the report finds that overexploitation is a threat to some species, it also highlights many examples of wild species being used sustainably, and recommends ways to support and replicate those methods.
But independent scientists say that the assessment falls short in its assessment of people’s uses of wild species. They point to significant gaps in the evidence underpinning the assessment. It “underestimates the harm that exploitation of wildlife does to nature and it exaggerates the benefits”, says biologist Daniela Freyer, co-founder of the conservation organization Pro Wildlife in Munich, Germany.
A summary of the assessment, which was conducted by the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES), was released on 8 July, with a full report to come in a couple of months. It will follow a 2019 IPBES report, which found that exploitation of wildlife is one of the largest drivers of biodiversity loss. The latest report builds on that finding and sought to offer a more optimistic message, says Marla Emery, a co-chair of the assessment.
The report, whose authors consisted of individuals with Indigenous and local knowledge, as well as scientists nominated by governments, reviewed more than 6,200 sources, including research papers and reports. From those, they calculated that people rely on roughly 33,000 species of plants and fungi, 7,500 species of fish and aquatic invertebrates, and 9,000 species of amphibians, insects, reptiles, birds and mammals. However, those are probably conservative numbers, says John Donaldson, another report co-chair.
According to one assessment cited in the report, of about 10,000 species used by people, roughly one-third have stable populations, which suggests they are being used sustainably. The rest show evidence of population declines, which could be driven by humans.
But Alice Hughes, a conservation biologist at the University of Hong Kong, questions how sustainable the use of some species described in the report actually are. For instance, the assessment does not consider whether trade affects animals’ morphology, she says. Trade that removes large ‘trophy’ animals from an ecosystem could reduce the size of the animals left behind, shrinking the gene pool and making them less resilient to environmental changes, says Hughes.
Researchers also question the decision not to prioritize how wildlife overexploitation affects disease outbreaks. The close interactions between people and wild animals has become a hot topic, given the strong evidence that the COVID-19 pandemic probably originated in a wildlife market in Wuhan, China. “Governments are going to take the exploitation of wild animals more seriously when they realize that there are genuine biosecurity risks,” says Hughes.
Factors that contribute to the unsustainable use of wild species include unregulated global trade and increased demand, armed conflict and climate change. The report finds that giving communities secure land rights, together with awareness-raising and scientific research, can support sustainable practices. The assessment recommends that policies are designed to ensure that the costs and benefits of using wildlife are shared equitably, and that they draw on diverse forms of scientific and local knowledge.
The report reveals just how reliant people are on wild species globally, says Anastasiya Timoshyna, programme coordinator for TRAFFIC, a wildlife-trade monitoring network in Cambridge, UK. These insights “couldn’t have come at a better time”, she says. Countries are currently negotiating the next global biodiversity agreement, which will set the conservation agenda until 2030.
But some researchers point to significant gaps in the evidence underpinning the report’s assessment. It probably vastly underestimates the total number of species being traded, says Hughes. For example, in May, she and her colleagues found that 1,264 species of arachnid are being traded, most caught in the wild, and many of those are probably not accounted for in the report1.
Data on some of the species the report finds are being used sustainably are also lacking, say researchers. It is difficult to conclude that species are being traded sustainably on the basis of limited scientific evidence, says Mark Auliya, a conservation biologist at the Leibniz Institute for the Analysis of Biodiversity Change in Bonn, Germany.
The report also fails to grapple with how much of the wild species’ use is for people’s survival, as opposed to for luxury items, and potentially dispensable, says Stuart Pimm, a conservation scientist at Duke University in Durham, North Carolina. “There are some really tough questions for which we need to have good quantitative answers.”
Data are especially sparse on the use of wild plants and trees. Even for highly valuable commodities such as timber, most trees are traded under genus or other collective names, without knowledge of their species, says Malin Rivers, who leads conservation efforts at Botanic Gardens Conservation International in London. “As one species gets depleted in the forest, people just move on to the next species.” But even with limited data, it is important to use the best available information to draw conclusions, she adds.
Emery says that the report’s authors carried out a comprehensive review of sources available until April 2021, so will have missed some of the latest research. She also acknowledges that massive knowledge gaps remain around the use of wildlife and whether that is sustainable, which is a finding of the assessment. But data gaps shouldn’t slow efforts to implement sustainable practices, she says. “We want as much science as we can get, but there is already a deep and important source of knowledge that we can use — and this is Indigenous local knowledge.”