What is a consequence of the loss of biodiversity?

News Release 12-083

First comprehensive effort to compare biodiversity loss to other human-caused environmental changes

May 2, 2012

This material is available primarily for archival purposes. Telephone numbers or other contact information may be out of date; please see current contact information at media contacts.

Loss of biodiversity appears to affect ecosystems as much as climate change, pollution and other major forms of environmental stress, according to results of a new study by an international research team.

The study is the first comprehensive effort to directly compare the effects of biological diversity loss to the anticipated effects of a host of other human-caused environmental changes.

The results, published in this week's issue of the journal Nature, 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.

"This analysis establishes that reduced biodiversity affects ecosystems at levels comparable to those of global warming and air pollution," said Henry Gholz, program director in the National Science Foundation's Division of Environmental Biology, which funded the research directly and through the National Center for Ecological Analysis and Synthesis.

"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 paper.

"Our results show that future loss of species has the potential to reduce plant production just as much as global warming and pollution."

Studies over the last two decades 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 such as food, clean water and a stable climate.

Until now, it's been unclear how biodiversity losses stack up against other human-caused environmental changes that affect ecosystem health and productivity.

"Loss of biological diversity due to species extinctions is going to have major effects on our planet, and we need to prepare ourselves to deal with them," said ecologist Bradley Cardinale of the University of Michigan, one of the paper's co-authors. "These extinctions may well rank as one of the top five drivers of global change."

In the study, Hooper, Cardinale and colleagues combined data from a large number of published studies to compare how various global environmental stressors affect two processes important in ecosystems: plant growth and the decomposition of dead plants by bacteria and fungi.

The study involved the construction of a database drawn from 192 peer-reviewed publications about experiments that manipulated species richness and examined their effect on ecosystem processes.

This global synthesis found that in areas where local species loss during this century falls within the lower range of projections (losses of 1 to 20 percent of plant species), negligible effects on ecosystem plant growth will result, and changes in species richness will rank low relative to the effects projected for other environmental changes.

In ecosystems where species losses fall within intermediate projections of 21 to 40 percent of species, however, species loss is expected to reduce plant growth by 5 to 10 percent.

The effect is comparable to the expected effects of climate warming and increased ultraviolet radiation due to stratospheric ozone loss.

At higher levels of extinction (41 to 60 percent of species), the effects 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 in experiments simulating several other major environmental changes caused by humans," Hooper said.

"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.

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 effects 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 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 Byrnes of the National Center for Ecological Analysis and Synthesis; Bruce Hungate of Northern Arizona University; Kristen Matulich of University of California, Irvine; Andrew Gonzales 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.

-NSF-

Media Contacts
Cheryl Dybas, NSF, (703) 292-7734, email:
Jim Erickson, University of Michigan, (734) 647-1842, email:

The U.S. National Science Foundation propels the nation forward by advancing fundamental research in all fields of science and engineering. NSF supports research and people by providing facilities, instruments and funding to support their ingenuity and sustain the U.S. as a global leader in research and innovation. With a fiscal year 2022 budget of $8.8 billion, NSF funds reach all 50 states through grants to nearly 2,000 colleges, universities and institutions. Each year, NSF receives more than 40,000 competitive proposals and makes about 11,000 new awards. Those awards include support for cooperative research with industry, Arctic and Antarctic research and operations, and U.S. participation in international scientific efforts.

Connect with us online
NSF website: nsf.gov
NSF News: nsf.gov/news
For News Media: nsf.gov/news/newsroom
Statistics: nsf.gov/statistics/
Awards database: nsf.gov/awardsearch/

Follow us on social
Twitter: twitter.com/NSF
Facebook: facebook.com/US.NSF Instagram: instagram.com/nsfgov

Estimates of species loss are, without a doubt, staggering. In 2007, Sigmar Gabriel, the then-Federal Minister for the Environment, Nature Conservation and Nuclear Safety of Germany, cited estimates that up to 30% of all species will be extinct by 2050 if climate change continues to progress as it has been. Others have estimated that as many as 140,000 species are lost each year. The alarming trends have led some to declare the current period the "Sixth Mass Extinction."

But, extinctions—even mass extinction events—are not new. Though the current trend is caused, undeniably, by human action—through poaching, habitat destruction, pollution, and anthropogenic climate change, among others—mass reductions in biodiversity can and have occurred without human interference.

The question then, is what does humanity lose when global biodiversity is significantly reduced?

Simply: a lot. Here are six significant human problems caused by reduced biodiversity.

Topping the list, of course, is the monetary value of biodiversity around the world. In terms of ecosystem services—functions like pollination, irrigation, soil reclamation, and other things that would have to be paid for if nature couldn't take care of it on its own—the value of global biodiversity has been estimated in the trillions. Because of this, deforestation alone has been estimated to cost between $2-5 trillion annually worldwide.

Reductions in biodiversity do not only occur during deforestation or through poaching. The introduction of new species is another culprit. These new species increase competition amongst locals and often lead to the extinction of native populations. In much of the world, this is happening on farms, too, where foreign breeds of cattle are being imported, pushing out natives.

This means that the world's livestock population is becoming increasingly narrow and more vulnerable to disease, drought, and changes in climate, leading to an overall reduction in food security.

The loss of biodiversity has two significant impacts on human health and the spread of disease. First, it increases the number of disease-carrying animals in local populations. Research has shown that the species best adapted to survive critically fragmented habitats are also the most prolific carriers of pathogens. As habitats are broken apart and reduced in size, these animals become more common, winning out over the species that do not typically transmit disease.

At the same time, habitat fragmentation brings humans in closer and more frequent contact with these disease-carrying species.

If forecasting the weather seems simply a matter of deciding to bring an umbrella or not, ask any farmer or coastal homeowner how they feel. Indeed, unseasonable weather, extreme weather, and weather that does not perform to historical norms is a huge problem that can lead to drought, destruction, and displacement.

The loss of species—even those replaced by invasives—has been shown to cause more unpredictable weather.

From fishermen to farmers, biodiversity—not to mention healthy ecosystems—is essential to maintaining livelihoods. When ocean ecosystems collapse, for example, entire communities built on the bounty they provide fold as well. Whether the cause is pollution, overfishing, ocean acidification, or a combination of these and more, humans are tied to the downfall of the ecosystems that surround them.

Beyond the utility of nature, of course, is the value of Nature to humanity. While an understanding of the science of the natural world does not diminish its grandeur, the physical deflation of it certainly does. When people finally look up from their desks and out their windows, will they be surprised by what remains?