Humans Fall Victim as Ecosystems Fall out of Balance

A dramatic die-off of vultures in India due to accidental poisoning was associated with a greater than 4 percent increase in human death rates from 2000 to 2005. Such was the finding of a study by Drs. Eyal Frank of the University of Chicago and Anant Sudarshan of the University of Warwick, published in 2023 by the Becker Friedman Institute for Economics. The loss of the scavenging services provided by vultures led to an increase in feral dogs, rabies, and rodents and a reduction in water quality from decomposing carcasses befouling freshwater sources.

In another study, published this year in Science, Dr. Frank reported a nearly 8 percent increase in human infant mortality in US counties that had experienced a precipitous decline in bat populations due to the fungal disease white-nose syndrome. The connection: Frank found that, from 2006 to 2017, farmers in these counties had increased the use of insecticides known to have adverse effects on human health by over 31 percent to compensate for natural insect control provided by bats. In the affected counties, the corresponding economic cost of the decline in bats, including direct cost to farmers and the “value of statistical life” (the US government’s monetary estimate of how much society values reducing the risk of death), was found to be $39.4 billion.

Such stark evidence of how biodiversity and ecosystem function are inextricably linked to human health and economic self-interest should inform future conservation policies: Saving biodiversity is, quite literally, saving ourselves.

Program Terms: Terrestrial Wildlife

AWI Quarterly Terms: Feature Article