The American pika is one species which may need a helping human hand according to some conservation biologists. Photo: Justin via flickr.
You probably seen reports on how global climate change is going to force migrations of animals into new ranges where the climate is more favorable to them. But what about humans assisting with this habitat shift? Not inadvertently, as we've seen happen with invasive species, but rather giving some species (who may not be able to migrate quickly enough on their own) a little helping hand. A new piece in Yale Environment 360 examines the pros and cons on assisted migration:Assisted Migration or Assisting Invasive Species?
Considering the havoc that some invasive species have caused, the entire idea of assisted migration (or managed relocation, as it is also called) raises the hackles of some scientists. But since 2007, when an article in Conservation Biology proposed that conservation biologists should openly discuss the benefits and risks of moving species at risk because of climate change, strong voices have been expressed on both sides.
In July 2008, a group of leading conservation biologists published a piece in Science in which they argued that there might be little choice but to move some species. "The future for many species and ecosystems is so bleak that assisted colonization might be their best chance," they wrote. Camille Parmesan, one of the co-authors and a biologist at the University of Texas, has pointed to the American pika as a candidate. The Ecological Society of Australia has endorsed managed relocation as well as a way to help species cope with climate change.
Up until now, however, all the talk about managed relocation to defend against climate change has been in the abstract. No one had any hard data on how such a move might turn out.
UK Butterfly Experiment Shows Assisted Migration Could Work
That all changed when researchers from the University of Durham in the UK published the results of an experiment that began in 2000, wherein they moved 500 butterflies 65 kilometers north of their present range and studied how they were doing, in the February 2009 issue of Conservation Letters.
With some data published showing that assisted migration can work, the whole idea moved from the abstract to the practical and aroused vocal opposition: Planned introductions of species don't always work as well as moving butterflies around.
But Not All Introductions Are Without Unintended Consequences
Wildlife managers introduced a North American freshwater shrimp into Flathead Lake in Montana to feed kokanee salmon (that were themselves introduced for fishing). The nocturnal shrimp avoided the diurnal salmon and began gobbling up zooplankton the salmon were eating. The salmon population crashed, and so did the eagle population that depended on it.
Then there is the very real concern that even if you could help some species, you're inevitably not going to be able to help all of those which could use a boost in moving into new habitats. How do you determine which species to help?
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