Friday, June 8, 2012

Climate Change & Homeless Mammals

Squirrel Monkey- Wikimedia
Regardless of what or who is to blame or what we can do about it, there can no longer be any doubt that we are in a period of significant warming of our planet.  An article in sciencenews.org summarizes the dramatic temperature data and some of its effects from across the nation.

In addition to the immediate effects we are seeing in plant growing seasons and insect responses, there are the long term effects on mammal populations which remain unknown.  ScienceNews.org reports on a new study appearing in the Proceedings of the National Academy of Sciences concerning the effect of climate change on mammal survival.

They estimate that 9 percent of mammals in the Western Hemisphere could become "climate refugees" within the century.  Earlier studies have looked at whether there would be suitable climate niches for mammals.  This study looks at whether they would be able to make the move into those areas.  They evaluated how far different species could move to establish new territories with the appropriate climate.

Most mammals move only when they are preparing to breed.  They identified 493 mammal species which could not move quickly enough.  Limitations included size (imagine the time moles and mice would require to move significant distances) as well as age of fertility and frequency of breeding.  Breeding rates are especially important in squirrel monkeys.  Sixty one percent of species are all ready threatened and 80% are "unlikely to keep pace with climate change."

Mountain dwelling species are at special risk.  Their only strategy is to move up the mountain to higher/cooler altitudes.  Unfortunately, as you go up a mountain (think of a pyramid) the area becomes smaller until you hit the peak. *

None of this migration takes into account whether the new territory would have suitable flora as these areas would be in flux because of climate change as well.  They also might find that the neighborhood is all ready populated by competing species and more efficient predators.

The planet is constantly changing- weather, habitat and species interactions.  Twelve thousand years ago as the glaciers retreated north of the Missouri River, Springfield was part of a boreal forest with megafauna such as giant sloths, short faced bears and wooly mammoths.  The one certainty is that 14,012 will look a lot different- to someone or something.

The abstract and full text are available at this pnas.org site.

* This description comes from a newly published book, Rambunctious Garden: Saving Nature in a Post-Wild World by Emma Marris.  I would highly recommend it for a great overview of the possible strategies in dealing with our current ecological challenges.  Her overview is here on Youtube.

Another example is found in this article at scientificamerican.com.


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