The L.A. River is getting a massive makeover.

To many Angelenos, the cement-lined urban waterway has become a symbol of hope that an environmental harm can be remedied. To that end, a number of small revitalization projects are now underway, and a planned $1.6 billion U.S. Army Corps of Engineers effort would remove concrete and replant native habitat along an 11-mile section.

But it’s not clear exactly what that will mean for local wildlife.

This Sunday, UCLA ecologist Brad Shaffer will join Los Angeles Times writer and columnist Patt Morrison and others on a panel of experts to explore the issue of “Life in the L.A. River” at the Natural History Museum from 3-5 p.m. The event, which is open to the public free with advance registration, is being sponsored by the museum and the UCLA La Kretz Center for Conservation Science.

Shaffer says it’s not surprising that the river, having been so heavily modified, is dominated by non-natives.

“In terms of all aquatic species, I’d be shocked if 10 percent were native,” he says. 

Some activists, including one prominent group that has long advocated for the waterway’s restoration — Friends of the Los Angeles River — say they’ll only be satisfied when California steelhead trout can once more inhabit the river.

But would a healthy, functioning river be a failure if native fish and amphibian species weren’t part of it? Shaffer doesn’t think so. To him, efforts to restore habitat and wildlife need to be realistic given how drastically people have changed the natural environment.

After a series of floods devastated property decades ago and claimed lives in the rapidly growing metropolis, the Army Corps of Engineers began a project in 1938 that would eventually seal 51 miles of the river with 13 million barrels of concrete. The endeavor halted the floods but destroyed ecosystems and transformed the river into a flood channel that fast-tracks polluted runoff into the Pacific Ocean.

Non-native fish such as carp have an advantage in an urban landscape: People continuously release them into the river. But many native fish can only return with a similar helping hand as well as strategies to maintain them once they are re-stocked.

Such interventions are not included in the $1.6 billion restoration project. But after masterminding the river’s initial paving back in 1938, the Army Corps of Engineers aims to make the river much more wildlife friendly.

“We’re trying to replicate the physical conditions that native species like as much as possible, but we aren’t proposing to bring animals back,” says Eileen Takata, lead planner with the agency.

However, there is a bright spot for one native fish. A heavy El Niño rainfall could wash the Santa Ana sucker, which currently lives farther upstream, down to the project area.

Whatever the long-term outcome, UCLA’s Shaffer sees the river as a fascinating example of urban ecology, where species’ adaptive resilience can be observed in the presence of dense human development.

Having been involved in conservation projects across California, Shaffer says success metrics vary with differing levels of human population density. A project in Yosemite’s Tuolumne Meadow, for example, would aim for 100 percent native species.

A more likely scenario in L.A. is an ecosystem in which non-natives and increasing numbers of native species live in harmony — and that’s not a bad thing, Shaffer says.

Food webs of predominantly non-native turtles, crayfish and snails could support increasing populations of native birds, such as cormorants and great blue herons.

This story appears on the UCLA Institute of the Environment and Sustainability website.

To attend Sunday’s panel discussion, register online or by phone by calling 213-763-3466.