Ecosystem effects of biodiversity loss could rival impacts of climate change, pollutionMay 03, 2012
The study is the first comprehensive effort to directly compare the impacts of biological diversity loss to the anticipated effects of a host of other human-caused environmental changes.
The results highlight the need for stronger local, national and international efforts to protect biodiversity and the benefits it provides, according to the researchers, who are based at nine institutions in the United States, Canada and Sweden.
"Loss of biological diversity due to species extinctions is going to have major impacts on our planet, and we better prepare ourselves to deal with them," said University of Michigan ecologist Bradley Cardinale, one of the authors. The study is scheduled for online publication in the journal Nature on May 2.
"These extinctions may well rank as one of the top five drivers of global change," said Cardinale, an assistant professor at the U-M School of Natural Resources and Environment and an assistant professor in the Department of Ecology and Evolutionary Biology.
Studies over the last two decades have demonstrated that more biologically diverse ecosystems are more productive. As a result, there has been growing concern that the very high rates of modern extinctions - due to habitat loss, overharvesting and other human-caused environmental changes - could reduce nature's ability to provide goods and services like food, clean water and a stable climate.
But until now, it's been unclear how biodiversity losses stack up against other human-caused environmental changes that affect ecosystem health and productivity.
"Some people have assumed that biodiversity effects are relatively minor compared to other environmental stressors," said biologist David Hooper of Western Washington University, the lead author of the Nature paper. "Our new results show that future loss of species has the potential to reduce plant production just as much as global warming and pollution."
In their study, Hooper and his colleagues used combined data from a large number of published studies to compare how various global environmental stressors affect two processes important in all ecosystems: plant growth and the decomposition of dead plants by bacteria and fungi. The new study involved the construction of a data base drawn from 192 peer-reviewed publications about experiments that manipulated species richness and examined the impact on ecosystem processes.
The global synthesis by Hooper and his colleagues found that in areas where local species loss this century falls within the lower range of projections (loss of 1 to 20 percent of plant species), negligible impacts on ecosystem plant growth will result, and changes in species richness will rank low relative to the impacts projected for other environmental changes.
In ecosystems where species losses fall within intermediate projections (21 to 40 percent of species), however, species loss is expected to reduce plant growth by 5 to 10 percent, an effect that is comparable in magnitude to the expected impacts of climate warming and increased ultraviolet radiation due to stratospheric ozone loss.
At higher levels of extinction (41 to 60 percent of species), the 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.
Authors of the Nature paper, in addition to Hooper, Cardinale and Duffy, are: E. Carol Adair of the University of Vermont and the National Center for Ecological Analysis and Synthesis; Jarrett E.K. Byrnes of the National Center for Ecological Analysis and Synthesis; Bruce Hungate of Northern Arizona University; Kristen Matulich of University of California Irvine; Andrew Gonzalez of McGill University; Lars Gamfeldt of the University of Gothenburg; and Mary O'Connor of the University of British Columbia and the National Center for Ecological Analysis and Synthesis.
Funding for the study included grants from the National Science Foundation and the National Center for Ecological Analysis and Synthesis.
"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.
University of Michigan
Related Biodiversity Current Events and Biodiversity News Articles
More logging, deforestation may better serve climate in some areas
Replacing forests with snow-covered meadows may provide greater climatic and economic benefits than if trees are left standing in some regions, according to a Dartmouth College study that for the first time puts a dollar value on snow's ability to reflect the sun's energy.
An ecosystem-based approach to protect the deep sea from mining
Five hundred miles southeast of Hawai'i, in international waters far out of sight of any land, there are vast mineral resources 5,000 meters below the sea.
Antarctic fjords are climate-sensitive hotspots of diversity in a rapidly warming region
Deep inside the dramatic subpolar fjords of Antarctica, researchers from the University of Hawai'i at Mānoa have discovered an unexpected abundance and diversity at the seafloor.
Study documents catastrophic collapse of Sahara's wildlife
A new study led by the Wildlife Conservation Society and Zoological Society or London warns that the world's largest tropical desert, the Sahara, has suffered a catastrophic collapse of its wildlife populations.
Scripps Leads First Global Snapshot of Key Coral Reef Fishes
In the first global assessment of its kind, a science team led by researchers at Scripps Institution of Oceanography at UC San Diego has produced a landmark report on the impact of fishing on a group of fish known to protect the health of coral reefs.
To boost concern for the environment, emphasize a long future, not impending doom
Looking back on a nation's past can prompt action that leads to a greener future, according to new research published in Psychological Science, a journal of the Association for Psychological Science.
Large study shows pollution impact on coral reefs -- and offers solution
One of the largest and longest experiments ever done to test the impact of nutrient loading on coral reefs today confirmed what scientists have long suspected - that this type of pollution from sewage, agricultural practices or other sources can lead to coral disease and bleaching.
Climate change may disrupt flight season of Canadian butterflies
The flight season timing of a wide variety of butterflies is responsive to temperature and could be altered by climate change, according to a UBC study that leverages more than a century's worth of museum and weather records.
The Gorgons of the eastern Pacific: scientists describe 2 new gorgonian soft coral species
Gorgonians are a type of soft corals easily distinguishable by the complex branching shape, which has also probably inspired their name, coming from the Gorgon Medusa- a creature from the Greek mythology that had hair made of venomous snakes.
Expert assessment: Ocean acidification may increase 170 percent this century
In a major new international report, experts conclude that the acidity of the world's ocean may increase by around 170% by the end of the century bringing significant economic losses.
More Biodiversity Current Events and Biodiversity News Articles