David U. Hooper, et al. A global synthesis reveals biodiversity loss as a major driver of ecosystem change. Nature, 2012; DOI: 10.1038/nature11118

“This analysis establishes that reduced biodiversity affects ecosystems at levels comparable to those of global warming or air pollution,” said Henry Gholz, program director in the National Science Foundation’s Division of Environmental Biology, which funded the research.

In ecosystems where species losses fall 21 to 40 percent, species loss is expected to reduce plant growth by 5 to 10%, equal to expected losses from climate warming and increased UV radiation due to stratospheric ozone loss.

At evels of extinction 41-60%,  impacts of species loss ranked with those of many other major drivers of environmental change, such as ozone pollution, acid deposition on forests, and nutrient pollution.

“Within the range of expected species losses, we saw average declines in plant growth that were as large as changes seen in experiments simulating several other major environmental changes caused by humans,” Hooper said. “I think several of us working on this study were surprised by the comparative strength of those effects.”

The strength of the observed biodiversity effects suggests that policymakers searching for solutions to other pressing environmental problems should be aware of potential adverse effects on biodiversity, as well, the researchers said.

Still to be determined is how diversity loss and other large-scale environmental changes will interact to alter ecosystems. “The biggest challenge looking forward is to predict the combined impacts of these environmental challenges to natural ecosystems and to society,” said J. Emmett Duffy of the Virginia Institute of Marine Science, a co-author of the paper.