This same pattern of less diverse communities being made up of species that are more susceptible to disease infection may well play out in more complex ecosystems as well, Johnson said. That's because species that disperse quickly across ecosystems appear to trade off the ability to quickly reproduce with the ability to develop disease resistance.
"This research reaches the surprising conclusion that the entire set of species in a community affects the susceptibility to disease," said Doug Levey, program director in the National Science Foundation's Division of Environmental Biology, which helped fund the research. "Biodiversity matters."
The sheer magnitude of the recent study also reinforces the connection between deformed frogs and parasitic infection, Johnson said. Beginning in the mid-1990s reports of frogs with extra, missing or misshapen legs skyrocketed, attracting widespread attention in the media and motivating scientists to try to figure out the cause. Johnson was among the researchers who found evidence of a link between infection with Ribeiroia and frog deformities, though the apparent rise in reports of deformations, and its underlying cause, remains controversial.
While the new study has implications beyond parasitic infections in amphibians, it does not mean that an increase in biodiversity always results in a decrease in disease, Johnson cautioned. Other factors also affect rates of disease transmission. For example, a large number of mosquitoes hatching in a particular year will increase the risk of contracting West Nile virus, even if there has been an incr
|Contact: Pieter Johnson|
University of Colorado at Boulder