The idea that natural communities rich in species are healthier and more productive has been an axiom in ecology for decades. The theory has been cited to support conservation programs and other efforts to maintain the complexity of natural systems. But hard evidence for this relationship has been tough to come by. The dynamics of different climates, communities, soils, and species have long confounded searches for a smoking gun.
Now, an international group of scientists has solved this long-standing ecological riddle. Using a bevy of new analysis techniques, they examined data from more than a thousand grassland plots around the world. Their findings, published in the journal Nature, demonstrates for the first time that conserving biodiversity is critically important in the real world.
“This study shows that you cannot have sustainable, productive ecosystems without maintaining biodiversity in the landscape,” said research ecologist Jim Grace of the USGS, the study's leader.
Biodiversity has been hypothesized to maintain the stability of natural ecosystems and provide benefits such as oxygen, soils, and water detoxification. While theoretical studies and experiments in artificially created ecosystems have supported this claim, scientists have struggled for the last half-century to isolate such an effect in the real world.
A global study network
The scientists used data collected for this research by a global consortium, the Nutrient Network, from over a thousand grassland plots spanning five continents. The plots included sites at the NRS's Sagehen Creek Field Station in the Sierra Nevada, Sedgwick Reserve east of Santa Barbara, and Elliott Chaparral Reserve in San Diego. Other NRS reserves such as Hastings Natural History Reservation and McLaughlin Natural Reserve are part of the Nutrient Network but their data were not included in this study.
Using advances in analytical methods, the group was able to isolate the effects of biodiversity from other factors such as climatic gradients and evolutionary history.
Evidence of biodiversity's value
“The intensive collaborative data collection by scientists around the world—work coordinated by a few of us at the University of Minnesota—allowed us to push forward the boundaries of knowledge about ecosystems and global biodiversity,” says Elizabeth Borer, an associate professor in the Department of Ecology, Evolution and Behavior (EEB) at the University of Minnesota. Borer and colleague Eric Seabloom, who began his career conducting research at the NRS, launched the Nutrient Network in 2007.
“These results suggest that if climate change leads to reduced species or genetic diversity, which is a real possibility, that then could lead to a reduced capacity for ecosystems to respond to additional stresses,” says Debra Willard, Coordinator for the USGS Climate Research & Development Program.
As an indication of the global awareness of this issue, the Intergovernmental Platform on Biodiversity and Ecosystem Services (the IPBES) was recently created to help policymakers understand and address problems stemming from the global loss of biodiversity and degradation of ecosystems.
—University of Minnesota