Iron heron sculptures stand by the Los Angeles River--a concrete-lined waterway proposed for restoration to its natural state. (Photo by David McNew/Getty Images)

Fake herons stand by the concrete-lined Los Angeles River–a candidate for restoration to its natural state. (Photo by David McNew/Getty Images)

Not long ago in the New Jersey Meadowlands, a private company took a 235-acre chunk out of an existing 587-acre protected area and turned it into a “mitigation bank.” The company running the deal paid $6 million for a lease and $25 million for restoration work, altogether about $132,000 an acre. The work involved removing tall, dense stands of phragmites (an invasive grass), knocking down berms along the Hackensack River, cleaning up contaminated soil, and replanting with native species. The idea was to create a bank of mitigation credits for sale at a profit to developers wanting to fill wetlands elsewhere.

The project did not create a single new acre of wetlands. While it did restore stands of spartina grass and other native species, says Erik Kiviat, an ecologist with the conservation nonprofit Hudsonia Ltd., the restoration effort also turned the habitat of a rare plant into an equipment parking lot, killed the last remnant of bluejoint grass wet meadow in the region, and destroyed what had been the state’s only known habitat for a globally rare invertebrate, Mattox’s clam shrimp. Moreover, the mitigation credits for this work require the company to monitor the restored acreage for just 15 years. After that, almost anything can happen. But the wetlands being filled thanks to mitigation credits will remain filled forever.

In the public imagination, there’s always been something tantalizing about the idea that we can restore trashed ecosystems, or—as Joni Mitchell never put it—take a parking lot and put up paradise. But the reality is that too often, ecological restoration projects

are wonderful for business rather than for plants, animals, and the environment. And it is big business: We have spent $70 billion on wetland restoration projects alone in North America over the past 20 years. But when a 2012 study in PLOS Biology looked at 621 such projects, it found most had failed to deliver promised results or match the performance of natural wetlands, even decades after completion. Meanwhile, despite a 26-year-old federal policy dictating “no net loss” of wetlands, the National Wildlife Foundation estimates that 100,000 acres of natural wetlands are still disappearing every year.

The picture isn’t much better for river restoration projects. They are typically profitable for the companies doing the restoration work but often disappointing for the environment. A new study in the journal Ecological Indicators looked at 120 river restoration projects, mostly in Europe or North America, and found that while they were generally beneficial, they had no effect, or even a negative effect, about a third of the time. Likewise, a 2010 study examined 78 river restoration projects and found that “only two showed statistically significant increases in biodiversity” compared with similar sites that had not been restored. “They may be pretty projects,” said lead author Margaret Palmer of the University of Maryland, “but they don’t provide ecological benefits.”

One problem for restoration projects is that they have tended to be relatively simple, whereas nature is endlessly complex and nuanced. So even people sincerely attempting to bring back a damaged environment often find themselves on a frustrating trial-and-error treadmill.

It’s often hard to know for a particular location which factor is really limiting the recovery of a target species, says Jochem Kail of the University of Duisburg-Essen in Germany and the lead author of the Ecological Indicators study. “Is it water quality? Is it a source population that’s missing? Or is it a habitat that missing, and not just aquatic habitats, but terrestrial habitats?” he said. Planting native trees might seem to answer the requirements for a river site. But what if they’re not the tree species on which a certain insect species lays its eggs? And what if those insects are the ones certain fish would otherwise feed on?

Restoration projects have also often tended to be designed by engineers or geomorphologists rather than ecologists, and they often have an inclination to get something built, and damn the nuances: Reshape a river channel with bulldozers, add some rocks and wood baffles to slow the current down in places, plant the banks with something to prevent erosion, and then move on to the next project. They operate on what Palmer calls “the field of dreams hypothesis”: If you build something that looks like a pretty little river to us, plants and animals will come.

How to fix the problem and get restorations that are actually worth the money we spend on them? The first step is to get ecologists involved in every stage of the project, from planning to post-completion monitoring, on equal ground with the engineers and geomorphologists. “You need all three,” said Kail. A social scientist would also help, he said, because a restoration is far more likely to succeed if it engages the support of the local community.

Finally, all restoration projects should be judged not by what they do or what they build but on the outcomes they deliver—perhaps guaranteed with a bond posted by the project developer so that if a promised outcome doesn’t show up in year three, or year five, there are funds available to fix it.

If this sounds onerous, bear in mind that restoration projects are often the “feel good” means by which developers win permission to fill wetlands, kill wildlife, and do other environmental damage. Most of that destruction shouldn’t be happening in the first place, because wetlands provide a significant public value for wildlife, water supply, flood control, and carbon sequestration. Kiviat is still seething about a restoration project that enabled a company to build a large truck parking lot on wetlands in the New Jersey Meadowlands.  “The Meadowlands have gone from being a dumping ground for garbage to being a dumping ground for restoration projects,” he said.

Ecological restorations are still worth doing. But we should be doing them for the right reasons and in the right ways. Our restorations should be a lot more about science, and perhaps a little bit of art—and a lot less about business.