How Biodiversity Keeps Earth Alive

BIODIVERSITY: Native wildflowers add diversity to this prairie-like California grassland. Image: © David Hooper

Read the full article at Scientific American.

Losing just 21 percent of the species in a given ecosystem can reduce the total amount of biomass in that ecosystem by as much as 10 percent—and that’s likely to be a conservative estimate. And when more than 40 percent of an ecosystem’s species disappear—whether plant, animal, insect, fungi or microbe—the effects can be as significant as those caused by a major drought. Nor does this analysis take into account how species extinction can both be driven by and act in concert with other changes—whether warmer average temperatures or nitrogen pollution. In the real world environmental and biological changes “are likely to be happening at the same time,” Hooper admits. “This is a critical need for future research.”

Over the long term, maintaining soil fertility may require nurturing, creating and sparing plant and microbial diversity. After all, biodiversity itself appears to control the elemental cycles—carbon, nitrogen, water—that allow the planet to support life. Only by acting in conjunction with one another, for example, can a set of grassland plant species maintain healthy levels of nitrogen in both soil and leaf. “As soil fertility increases, this directly boosts biomass production,” just as in agriculture, Reich notes. “When we reduce diversity in the landscape—think of a cornfield or a pine plantation or a suburban lawn—we are failing to capitalize on the valuable natural services that biodiversity provides.”