Nav: Home

Fixing damaged ecosystems: How much does restoration help?

March 01, 2018

DeKalb, Ill. - Across the globe, billions of dollars are spent annually on repairing ecosystems damaged by people. Forests denuded by logging. Rivers polluted by industry. Grasslands converted to agriculture.

A new meta-analysis of 400 studies that document recovery from such large-scale disturbances worldwide suggests that while ecosystems can bounce back, they rarely mend completely, with the final stages of recovery being most difficult.

Surprisingly, the new study also found that more costly active restoration efforts did not consistently result in faster or more complete recovery.

"Our study suggests that, in many cases, once damaging activities are halted, the most economically expedient restoration strategy might be to let ecosystems repair themselves," Northern Illinois University scientist Holly Jones said. She led a team of researchers from five countries on the study, published in Proceedings of the Royal Society B.

"Our findings do not diminish the importance of active restoration efforts but instead suggest they can be planned more judiciously to maximize gains per dollar spent," added Jones, who holds a joint appointment with NIU's Department of Biological Sciences and the university's Institute for the Study of the Environment, Sustainability and Energy.

The science of ecological restoration is relatively young but important. Finding the best way to repair disturbed or damaged ecosystems is critical to stemming the biodiversity crisis. Every day, the planet's biodiversity is being lost at up to 1,000 times the natural rate, according to the IUCN Red List of Threatened Species.

Not to be confused with a do-nothing approach, passive recovery involves putting a halt to damaging practices or disturbances, such as removing dams that fragment rivers or stopping the practice of logging and grazing forests. Active restoration often follows, such as stabilizing riverbanks or planting trees in deforested areas.

"When feasible, passive recovery should be considered as a first option," Jones said. "Nature may not need much help after we stop degrading activities. If recovery is slow, then active restoration actions should be tailored to overcome specific obstacles.

"If we can focus only on systems that do get a significant added benefit, we can allocate restoration dollars more effectively and restore more ecosystems that truly need it," she added.

Because of its broad-brush scale, the meta-analysis likely failed to detect some instances where active restoration is speeding up recovery, Jones said. Tallgrass prairie in Illinois, for example, "absolutely requires active restoration," she said.

The meta-analysis looked specifically at the outcomes of only two critical goals: accelerating ecosystem recovery and achieving more complete recovery. Restoration efforts, however, could be making strides toward unstudied goals that are important to local stakeholders, such as creating greenways, floodplain or urban gardens.

"Another example would be after an oil spill, where action is needed because there are other goals that go beyond the rate or completeness of ecosystem recovery, such as making sure wildlife in the area doesn't die," Jones said.

She said the new study results should be interpreted cautiously for other reasons as well. Site managers could be choosing to perform restoration on more difficult sites, such as forests that have experienced clearcutting rather than selective cutting (harvesting only a proportion of trees).

Also, less than 5 percent of past studies from the literature compared active restoration to passive recovery within the same damaged site. To compensate, the researchers created a second, much larger data set, comparing recovery rates and completeness among different locations that experienced either active restoration or passive recovery. The two data sets yielded similar results.

The researchers identified positive recovery rates in all actively restored and passively recovering sites once damaging activities ceased, which means disturbed systems are regaining some of their biodiversity and ecosystem functionality. Most recovery rates were between 1 percent and 10 percent recovery per year, with rates consistently slowing over time.

The study authors cannot say for certain why restoration isn't resulting in faster or more complete recovery. To identify where and when restoration will be most effective in the future, they recommend that restoration practitioners build formal or informal experimentation into their designs, directly comparing passive recovery with one or more active restoration approaches.

"This has rarely been done in the past," said study co-author Karen Holl of the University of California, Santa Cruz. "These comparisons will help to show where active restoration efforts are most effective and how to better allocate scarce restoration funds."

Jones said the study also underscores the necessity of preserving untouched ecosystems.

"Restoration cannot be considered a substitute for conservation," Jones said. "Because damaged ecosystems rarely recover completely, conservation of ecosystems that are not damaged will be critical to reduce the loss of biodiversity and the valuable byproducts of ecosystems, such as clean water, clean air and medicines developed from their plants."
-end-


Northern Illinois University

Related Biodiversity Articles:

About the distribution of biodiversity on our planet
Large open-water fish predators such as tunas or sharks hunt for prey more intensively in the temperate zone than near the equator.
Bargain-hunting for biodiversity
The best bargains for conserving some of the world's most vulnerable salamanders and other vertebrate species can be found in Central Texas and the Appalachians, according to new conservation tools developed at the National Institute for Mathematical and Biological Synthesis (NIMBioS) at the University of Tennessee, Knoxville.
Researchers solve old biodiversity mystery
The underlying cause for why some regions are home to an extremely large number of animal species may be found in the evolutionary adaptations of species, and how they limit their dispersion to specific natural habitats.
Biodiversity offsetting is contentious -- here's an alternative
A new approach to compensate for the impact of development may be an effective alternative to biodiversity offsetting -- and help nations achieve international biodiversity targets.
Biodiversity yields financial returns
Farmers could increase their revenues by increasing biodiversity on their land.
Biodiversity and wind energy
The location and operation of wind energy plants are often in direct conflict with the legal protection of endangered species.
Mapping global biodiversity change
A new study, published in Science, which focuses on mapping biodiversity change in marine and land ecosystems shows that loss of biodiversity is most prevalent in the tropic, with changes in marine ecosystems outpacing those on land.
What if we paid countries to protect biodiversity?
Researchers from Sweden, Germany, Brazil and the USA have developed a financial mechanism to support the protection of the world's natural heritage.
Grassland biodiversity is blowing in the wind
Temperate grasslands are the most endangered but least protected ecosystems on Earth.
The loss of biodiversity comes at a price
A University of Cordoba research team ran the numbers on the impact of forest fires on emblematic species using the fires in Spain's Doñana National Park and Segura mountains in 2017 as examples
More Biodiversity News and Biodiversity Current Events

Trending Science News

Current Coronavirus (COVID-19) News

Top Science Podcasts

We have hand picked the top science podcasts of 2020.
Now Playing: TED Radio Hour

Listen Again: Reinvention
Change is hard, but it's also an opportunity to discover and reimagine what you thought you knew. From our economy, to music, to even ourselves–this hour TED speakers explore the power of reinvention. Guests include OK Go lead singer Damian Kulash Jr., former college gymnastics coach Valorie Kondos Field, Stockton Mayor Michael Tubbs, and entrepreneur Nick Hanauer.
Now Playing: Science for the People

#562 Superbug to Bedside
By now we're all good and scared about antibiotic resistance, one of the many things coming to get us all. But there's good news, sort of. News antibiotics are coming out! How do they get tested? What does that kind of a trial look like and how does it happen? Host Bethany Brookeshire talks with Matt McCarthy, author of "Superbugs: The Race to Stop an Epidemic", about the ins and outs of testing a new antibiotic in the hospital.
Now Playing: Radiolab

Dispatch 6: Strange Times
Covid has disrupted the most basic routines of our days and nights. But in the middle of a conversation about how to fight the virus, we find a place impervious to the stalled plans and frenetic demands of the outside world. It's a very different kind of front line, where urgent work means moving slow, and time is marked out in tiny pre-planned steps. Then, on a walk through the woods, we consider how the tempo of our lives affects our minds and discover how the beats of biology shape our bodies. This episode was produced with help from Molly Webster and Tracie Hunte. Support Radiolab today at Radiolab.org/donate.