Climate change has conservationists considering drastic steps they would never before consider – like planting forests of endangered trees in locations where they can thrive. Assisted migration is a controversial new concept that proposes replanting endangered tree seeds in regions that they don’t normally grow, but which will become ideal environments as the world keeps warming. This radical idea, which is still hypothetical, comes in response to the possibility that climate change will happen so fast that trees won’t be able to adapt on their own.
The whitebark pine tree has become a primary example of an endangered tree that not only faces natural enemies like fungus and beetles, but is also becoming a victim of climate change. When the Forest Service drafted a plan for restoring the whitebark pine in 2012, officials called for rebuilding whitebark pine populations by planting seedlings in place and setting controlled fires. Healthy forests of whitebark pine, they argue, should be better able to withstand climate change. The trees may even spread northward on their own as higher latitudes develop a suitable climate.
But what if the climate warms too quickly for the trees to respond? The solution, some conservationists say, may be to help the trees claim new territory more quickly. Assisted migration remains mostly hypothetical, but in 2007, Sally N. Aitken, a geneticist at the University of British Columbia, tested the idea. Dr. Aitken discovered that the northwestern corner of British Columbia had the right climate for the whitebark pine, but for reasons that weren’t clear, the trees didn’t grow there. Climate projections indicate that this region should be good for the trees in a century, so Sierra McLane, a graduate student working with Dr. Aitken, hiked into the remote mountain ranges of British Columbia and planted 18,000 whitebark pine seeds, some as far as 500 miles beyond the tree’s current range. About 20 percent of the seeds germinated. Seven years later the trees are still growing, even at the northernmost sites.
Critics have warned that assisted migrations like this could prove to be expensive failures. Even if they succeed, the rescued species may become invasive pests in their new habitat. Diana F. Tomback, director of the Whitebark Pine Ecosystem Foundation predicts that if the migrated trees are to survive in the long term, conservation biologists will have to figure out how to establish birds in their new range as well. Robert E. Keane, an ecologist at the Rocky Mountain Research Station, believes it would be wiser to find trees that can resist the fungus and use them to plant new forests, which should be maintained with fires. A less controversial variation of assisted migration involves moving plants or animals within their existing range.
Via New York Times