Teasing out ways that biodiversity loss “ripple[s] through ecosystems and affect[s] humans” can help make a case for preventive actions in the face of other ecological threats.
. Ninety of those species are presumed extinct. Frogs and toads in the Americas and Australia have suffered the greatest declines. The international trade in amphibians has spread the fungus globally.
Springborn and colleagues wondered if the impacts of the amphibian losses stretched to humans too. The researchers turned to Costa Rica and Panama, where the fungus moved through ecosystems in a somewhat uniform way along the narrow strip of land on which the two countries sit, Springborn says. This meant that the researchers could work out when the fungus arrived at a given place. The team also looked at the number of malaria cases in those places before and after the amphibian die-offs.
In the first couple of years after the animals’ decline, malaria cases started to rise. For the following six years or so, cases remained elevated, then started to go down again. The researchers aren’t sure yet what was behind the eventual drop. Studies on the connections between biodiversity loss and human health might “help motivate conservation by highlighting the direct benefits of conservation to human well-being,” says Hillary Young, a community ecologist at the University of California, Santa Barbara who was not involved in the work.
“Humans are causing wildlife to be lost at a rate similar to that of other major mass extinction events,” she says. “We are increasingly aware that these losses can have major impacts on human health and well-being — and, in particular, on risk of infectious disease.”