Extinctions could cut plant productivity in half

November 9, 2007
by Eve Savory, CBCNews.ca

In a study that has startled even its authors, scientists have concluded that the extinction of plant species can reduce an ecosystem’s ability to support life by up to fifty percent.
It’s called “productivity” and what a plant produces is essential to life on earth: oxygen. That’s not all. Plants produce food in crops, fibre in trees, clean water, and biofuels. And they suck the greenhouse gas carbon dioxide out of the atmosphere.
“Nature does things that support humanity that allow us to exist”, says Bradley Cardinale, the lead author. “The erosion of all those services is going to come back to bite us.”
In the study, published this week in the Proceedings of the National Academy of Sciences, the international group of researchers looked at 44 studies that had simulated species extinction in grasslands, estuaries and the tundra. What they found was that even if the dominant species survived, the ecosystem as a whole did its’ job less efficiently.
Michel Loreau of McGill University said “diverse communities are more productive because plants are ‘complementary’ in how they use biological resources. In other words, different plant species play unique roles.” The scientists say it’s like soccer. To succeed, the star needs her supporting players. Translate that into an ecosystem, and it means the plant species that survive produce less biomass, or plant matter.  More