May 3, 2015

Bringing Species Back from Extinction - How Far is too Far?

Woolly mammoth (Mammuthus primigenius) - Mauricio Antón
By Mauricio Antón [CC BY 2.5 (], via Wikimedia Commons

Scientists are currently working on how to bring extinct species back to the wild.  The passenger pigeon may one day make a reappearance in the United States.  This was an abundant species, whose demise was recent (early 1900s) and largely due to human impacts such as hunting.  What other species should be brought back from extinction?

Work is currently underway to bring the woolly mammoth back from extinction.  Is this a good idea?  The woolly mammoth lived nearly 10,000 years ago.  According to a TEDx talk given by Hendrik Poinar, the scientist in charge of this project, "there are swaths of habitat in the north of Siberia and Yukon that actually could house a mammoth."  He emphasized the ability of these animals to survive great changes in climate during their time, so maybe they could survive today.  Poinar also states that "we have to think very deeply about the implications, ramifications of our actions, and so as long as we have good, deep discussion like we're having now, I think we can come to a very good solution as to why to do it."  For some species I agree.  I'm not sure about the woolly mammoth though.

Environmentalist Stewart Brand is in favor of de-extinction.  In a 2013 TED talk he said, "humans have made a huge hole in nature in the last 10,000 years.  We have the ability now, and maybe the moral obligation, to repair some of the damage.  Most of that we'll do by expanding and protecting wildlands, by expanding and protecting the populations of endangered species.  But some species that we killed off totally we could consider bringing back to a world that misses them." 

Brand wrote an article for National Geographic where he mentions the woolly mammoth project, "In their absence, the grasslands they helped sustain were replaced by species-poor tundra and boreal forest.  Their return to the north would bring back carbon-fixing grass and reduce greenhouse-gas-releasing tundra."  

Just because we can bring back a species doesn't mean we should.  The climate has been changing, causing shifts in species ranges.  What used to be ideal habitat for an extinct species may no longer be a good home for them.  What about the change in species biodiversity that occurred when the species was lost?  Will the extinct species be able to find its former niche in the same location?  You can't simply return a species to a habitat that has adapted to function without it.  Returning woolly mammoths to the tundra and boreal forests is not going to convert them back to grassland.  Ecological succession has proceeded in their absence, creating a habitat that may not support their survival.  It is likely that all the animals would die.  

Before returning extinct species to the wild, plans need to be created, and measures of success need to be clarified.  What type of protection would species brought back from extinction receive?  If chicken DNA is used to help reconstruct the DNA of passenger pigeons, would the new passenger pigeons receive no protection because chickens are common?  Maybe they would receive no protection because they are a genetically modified organism (GMO).  Many humans are fearful of GMOs.  How do we convince a population that is scared of GMOs that the new passenger pigeons we want to reintroduce to their backyard are ok?  What would prevent these people from killing off the pigeons due to fear of genetic modification?  What actions would be implemented if the population starts to decline again for any reason?  How do we stop trophy hunters from killing off newly introduced woolly mammoths?  Just the chance to see one in the wild would attract a lot of attention.

In Brand's National Geographic article he also mentions that the revival of extinct species will help improve our understanding of why species went extinct.  This point has great potential!  If we can compare the DNA of a species that went extinct to species who survived at that time, there might be differences that would suggest a cause of extinction.  We could then look for these differences in modern species to help us identify ones prone to extinction.  

Do we need a live animal for to help us identify characteristics that made an extinct species prone to extinction at its time?  I don't think we do because we couldn't replicate all the environmental variables that impacted the species when it was alive to really understand those factors that helped push them toward extinction.  Why not just study the animals that are still alive that we are trying to save now?

In a study published May 1 in Science called "Accelerating extinction risk from climate change" author Mark C. Urban suggests that "extinction risks will accelerate with future global temperatures, threatening up to one in six species under current policies."  That is a lot of species!  Information to help us identify those species will improve their chance of survival.  But what if humans are one of them?  

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