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Butterfly on flowers
A butterfly on flowers at the University of South Florida campus.
A team of University of South Florida (USF) biologists and colleagues studying how and why infectious disease outbreaks occur found evidence that supports the controversial "dilution effect hypothesis," which suggests that biodiversity in nature limits outbreaks of disease among humans and wildlife.
"The dilution effect hypothesis is important because it warns that human-mediated biodiversity losses can exacerbate disease outbreaks, yet it has been contentiously debated, said David Civitello, lead author of the study and a postdoctoral researcher in the Department of Integrative Biology at USF. "Our study found broad evidence that species-rich communities suffer less infectious disease, and the magnitude of this effect was independent of host density, study design, type and specialization of parasites, and whether the parasite infected humans or wildlife, indicating that dilution was robust across all ecological contexts examined. This suggests that maintaining biodiversity in nature could reduce the abundance of many parasites of humans and wildlife." And he adds, "conversely, human-induced declines in biodiversity could contribute to increases in both human and wildlife diseases."
The team also found that plant biodiversity reduced the abundance of herbivore pests, meaning biodiversity can inhibit two types of harmful natural enemies--parasites and herbivore pests--that may in turn increase the stability and production of natural ecosystems.
The studys findings could have implications for public health and make a case for better management of natural systems, such as forests and croplands.
To learn more, see the USF news story University of South Florida biologists: biodiversity reduces human, wildlife diseases and crop pests . (Date image taken: May 2015; date originally posted to NSF Multimedia Gallery: Nov. 3, 2015)
Credit: Katy Hennig, University of South Florida
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