Assisted Migration Has Benefits, Costs

Oregon has its fair share of invasive species, such as nutria brought into the state for fur in the 1880s, and red-eared sliders, turtles that compete with our native western pond and painted turtles. Moving species from one place to another can wreak havoc on native ecosystems, but as climate change pushes species to extinction, conservationists have posed the idea of assisted migration, moving a species from its native range to a better-suited territory that more closely matches its ideal climate.

Panelists discussed assisted migration at a Public Interest Environmental Law Conference panel March 1 at the UO, weighing the benefits against the costs. The speakers said that assisted migration is an ecologically risky move, but as sea levels rise and temperatures flux faster than species can adapt, there may not be many other options.

“Not everyone agrees that assisted migration is a good idea,” said Josh Lawler, a professor in the School of Environmental and Forest Sciences at the University of Washington. “The main reason in favor of it is that if we don’t do it, a species will go extinct.”

Not all non-native species are invasive species, like European honeybees in Oregon, which aren’t native to the state but do not significantly harm ecosystem function. Lawler said that when it comes to assisted migration, there are varying degrees of interference, from connecting habitat so species can cross landscapes to actually transplanting species such as trees into a new environment.

Jaclyn Lopez, attorney for the Center for Biological Diversity, used the example of loggerhead sea turtles and sea level rise to illustrate why assisted migration may be necessary to save a species. She said that 90 percent of loggerhead sea turtle nesting occurs in Florida, and when the turtles mature, they return to their birth site to nest. “Decades later when they’ve matured, they could come back to a beach that is no longer there,” she said.

Ultimately, the speakers said, the survival of many species and ecosystems depends on our ability to slow down the onset of climate change. “None of this matters without mitigation of greenhouse gases,” Lopez said. “We’re screwed if we don’t get a handle on it.”