Frequent reports of accelerating species losses invariably raise questions about why such losses matter and why we should work to conserve biodiversity.
Biologists have traditionally responded to such questions by citing societal benefits that are often presumed to be offered by biodiversity--benefits like controlling pests and diseases, promoting the productivity of fisheries, and helping to purify air and water, among many others. Nevertheless, many of these presumed benefits are have yet to be supported by rigorous scientific data.
But Bradley J. Cardinale of the University of Michigan has produced a new study that finally verifies that biodiversity promotes water quality and explains how it does so. Specifically, the study reveals how biodiversity helps remove excess levels of nutrients from streams that commonly degrade water quality.
Cardinale said, "This is the first study that nails the mechanism by which biodiversity promotes water quality. And by nailing the mechanism, it provides solid evidence of a cause-and-effect relationship between biodiversity and water quality that was previously missing."
Here's how Cardinale's mechanism works: as the number of species of algae in a stream increases, the geographical distribution of these organisms within the stream expands, and the more water these widely distributed organisms may cleanse through a pollution-removing process common to algae.
Cardinale's study, which appears in the April 7 issue of Nature, was funded by the National Science Foundation.
The cleansing power of biodiversity
Scientists have long known that ecosystems that have more plant species tend to have a greater capacity to remove pollutants from soil and water than do ecosystems that have fewer species. But, until now, no one knew how or why this is so.
Cardinale's study helps solve this mystery by explaining how biodiversity promotes the self-cleaning po
|Contact: Lily Whiteman|
National Science Foundation