Glacier National Park’s Most Unique Insect, the Western Glacier Stonefly, Threatened by Climate Change

January 3, 2011

By: Nick Engelfried 

On Thursday the Center for Biological Diversity and the Xerces Society for Invertebrate Conservation filed a scientific petition urging the western glacier stonefly be granted protection under the US Endangered Species Act.  Confined to only five streams in Montana’s Glacier National Park, this rare and unusual insect is threatened by the disappearance of its icy habitat due to climate change.

Like other stoneflies—which are not true flies at all but member of an ancient insect order that evolved tens of millions of years ago—western glacier stoneflies spend the first stage of their lives as underwater “nymphs.”  When mature, the nymphs climb out of the water, shed their skins, and emerge as winged adults that take to the air in search of a mate. 

Stoneflies tend to be very sensitive to pollution and changes in water quality, and many are considered “indicator species” used to judge the overall health of aquatic ecosystems.  About 40% of stonefly species in North America are at risk of extinction because of pollution and other effects of human activity.  Yet even in comparison to other stonefly species, nymphs of the western glacier stonefly are especially vulnerable to small changes in the ecosystem around them.  They depend for their survival on very cold water of the type that melt off of mountain glaciers, and are found only in glacier-fed streams located at very high elevations in Glacier National Park.

For millions of years western glacier stoneflies have persisted in their cold habitat, protected from most human disturbances by their extreme isolation.  However now climate change is disrupting glacier ecosystems, putting this and other species at risk.  Of the 150 glaciers counted in Glacier National Park in 1850, all but twenty-five have already disappeared due to global warming.  Scientists predict the remaining glaciers may be gone from the park as soon as 2030 if major reductions in worldwide greenhouse gas emissions are not made.   “This species is just one more example of why we need to address climate change before it is too late,” said Sarah Foltz Jordan of the Xerces Society, referring to the imperiled stonefly.

Yet despite the fact that its only remaining habitat is fast disappearing, the western glacier stonefly is not currently listed for protection under the Endangered Species Act.  The conservation groups petitioning to list the insect hope inclusion on the Endangered Species List will help draw attention to the plight of the stonefly and other species threatened by climate change.  The Center for Biological Diversity, one of the groups involved, has also been at the forefront of the legal battle to protect polar bears, the mountain-dwelling pika, and other species threatened by a changing climate under the Endangered Species Act. 

“The loss of glaciers in Glacier National Park makes it clear that climate change is happening now,” said Noah Greenwald of the Center for Biological Diversity. “The impending loss of the western glacier stonefly is a harbinger of change that will result in the loss of millions of species, disruption of food production, loss of water storage in mountain glaciers, flooding of coastal areas and other impacts that threaten our very way of life.”

Scientists estimate one third of all plant and animal species risk becoming extinct by the year 2050 if major economies don’t dramatically curb their reliance on fossil fuels and the release of greenhouse gases into the atmosphere.  As the second largest annual emitter of these gases and the largest historical emitter, the United States is considered by many international policy observers to have a special responsibility to reduce its contribution to climate change and help avert the worst predicted effects of global warming.

Photo credit: Lee Coursey

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