Wild animal populations have declined 69% in 50 years, says WWF
The world’s populations of wild mammals, birds, amphibians, reptiles and fish have declined by more than two-thirds on average since 1970, according to a grim new report on biodiversity loss.
The Living Planet Report, released every two years since 1998 by the World Wildlife Fund, looks at how 32,000 populations of more than 5,000 species around the globe are faring by measuring their populations’ growth or decline. “Declines in abundance are early warning indicators of overall ecosystem health, and serious drops like this tell us that nature is unraveling,” states the report, which was produced in collaboration with the Zoological Society of London.
The report is based on WWF’s Living Planet Index of wildlife species.
This year researchers added 838 new species to the index, most of them from Latin America and Africa, regions that have been underrepresented in the past.
To make the index, an animal species must have been well monitored since at least 1970.
More information, however, only revealed in closer detail the vast destruction of animal life – particularly in tropical forests, which contain a disproportionate variety of the world’s plants and animals. Monitored populations in Latin America and the Caribbean showed an average drop of 94% since 1970. During the same period, those in Africa declined by 66%, while the Asia Pacific region’s shrank by 55%.
Other regions saw lesser declines: In North America, monitored populations dropped by 20%, and in Europe and Central Asia by a more modest 18%.
Some of the most dramatic declines occurred not on any continent but in oceans and waterways. WWF found an 83% decline in the abundance of species that rely on fresh water. Populations of sharks and rays have dropped by 71% over the last half century due to an 18-fold increase in fishing pressure from humans.
The destruction and fragmenting of natural habitats so that land can be farmed or developed is still the gravest danger to biodiversity on land. However, the report’s authors see a new existential threat on the horizon. “Climate change is likely to become the dominant cause of biodiversity loss in the coming decades,” they write. Rising temperatures are already linked to the loss of more than 1,000 plant and animal species, according to the report.
Eight years ago in Australia, a single hot day killed more than 45,000 “flying fox” bats. In 2016 the Bramble Cay melomys, a rodent that lived on an island between Australia and Papua New Guinea, was declared extinct after a rising sea swamped its sources of food and nesting sites.
“The science really, really supports us dealing with biodiversity loss and climate change as a single crisis,” Rebecca Shaw, WWF’s chief scientist, said in an interview.
Much of what ails plants and animals, like tropical forest loss, is also hampering the planet’s ability to pull greenhouse gases from the air, she said. But “a really well managed ecosystem can be an amazing sink for carbon,” as well as providing habitat and benefits to humans like clean air and water.