Recent research shows that declining bat populations are associated with a rise in human infant mortality rates, highlighting the critical role bats play in ecosystem balance. Picture: Jochemy / Pexels
A recent study published in the journal Science has unveiled a concerning correlation between declining bat populations and increased infant mortality rates in the United States.
The research, led by Eyal Frank, an environmental economist at the University of Chicago, reveals that the loss of bats due to white-nose syndrome – a disease caused by the fungus Pseudogymnoascus destructans – has had far-reaching consequences for human health.
White-nose syndrome, introduced to the US around 2006, has since decimated bat populations across at least 40 states. Frank's study discovered that in counties heavily affected by the disease, infant mortality rates rose by approximately 8 percent.
This translates to an estimated 1,334 additional infant deaths between 2006 and 2017, a figure Frank attributes directly to the decline in bat numbers.
The study’s premise emerged from Frank's observation of the spread of white-nose syndrome and its impact on bat populations. As bat numbers dwindled, Frank noted a corresponding increase in the use of insecticides by farmers, who resorted to these chemicals to compensate for the loss of bats’ natural pest control.
The study found that counties with significant bat declines saw a 31 percent rise in insecticide usage. This increase in toxic chemicals, Frank argues, likely contributed to the higher rates of infant mortality.
Frank’s rigorous analysis involved ruling out other potential factors affecting infant mortality, such as the opioid crisis, unemployment, genetically modified crops, and weather conditions. His findings suggest a direct link between the reduced insectivory of bats and adverse health impacts on humans.
Paul Ferraro, a sustainability scientist at Johns Hopkins University, described the study as presenting “the most convincing evidence to date” of the economic and health impacts resulting from the loss of a wild species. This research aligns with broader findings on ecosystem services — the benefits that ecosystems provide to human society.
Earlier studies have highlighted similar effects, such as the additional 500,000 deaths in India linked to the decline of vultures, and the 24 percent reduction in deer-related car accidents following the reintroduction of wolves in Wisconsin.
The study underscores the often-overlooked value of maintaining biodiversity and the ecosystem services provided by various species. The implications of his findings are profound, indicating that even local declines in species populations can have significant negative impacts on human health and well-being.
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