BONN, Germany (Landscape News) – Expensive landscape restoration efforts should be planned judiciously to maximize gains for each dollar spent because in some circumstances nature may not need much help after degrading activities are stopped, according to a new study.
A meta-analysis of 400 studies documenting landscape recovery from the consequences of such human activities as logging, industry and agriculture suggests that while ecosystems can recover, they rarely mend completely, according to the research published in Proceedings of the Royal Society B.
“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,” said scientist Holly Jones.
“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,” said 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.
“When feasible, passive recovery should be considered as a first option,” she 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.
However, the statement points out that the meta-analysis looked only at the outcomes of two goals: accelerating ecosystem recovery and achieving more complete recovery. It did not include an analysis of important active restoration efforts such as creating greenways, floodplain, urban gardens or repair after damaging environmental incidents.
“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.
Results should be interpreted cautiously for other reasons as well, the statement said.
Site managers could be choosing to perform restoration on more difficult sites, such as forests that have experienced clear-cutting rather than selective cutting.
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 statement said.
The study was inconclusive with regard to why restoration does not result in faster or more complete recovery, recommending that restoration practitioners build experimentation into designs to compare passive recovery with active restoration approaches.
“This has rarely been done in the past,” said study co-author Karen Holl of the University of California. “These comparisons will help to show where active restoration efforts are most effective and how to better allocate scarce restoration funds.”
Restoration should not be considered a substitute for conservation or preserving ecosystems intact, the study 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,” Jones said.