April 11, 2012
Ecosystems dependent on snow and ice may suffer the most adverse impacts from climate change, according to a body of information accumulated through the Long Term Ecological Research (LTER) Network, a project sponsored by the National Science Foundation (NSF).
For more than 30 years, the LTER has been collecting data from diverse ecosystems — deserts, lakes, prairies, forests and more — to better understand ecological forces that may unfold over decades and involve huge geographical areas.
LTER researcher Julia Jones and her team have studied data from 19 forested watersheds across the United States. Their findings indicate that when average temperatures increase in snowy ecosystems, a significant amount of stream water is lost to the atmosphere. They found this effect in the arid Southwest region of the United States where populated areas depend on the water that flows from mountain snowpack at higher elevations.
But forested ecosystems lacking winter snow fared better through rising temperatures. “Streams in dry forested ecosystems seem more resilient to warming, said Jones. “These ecosystems conserve more water as the climate warms, keeping stream flow within expected bounds.”
The long time span of the data collection allows scientists to assess a range of factors that have an impact on a watershed — human influence, periods of unusual drought or unusual precipitation. “Such nuanced insights are crucial to effective management of public water supplies,” said Jones.
The LTER Network includes 26 sites in North America, for example, Puerto Rico; the island of Moorea, in French Polynesia; and Antarctica. The network has amassed environmental data from these sites over three decades, documenting gradual changes and long-term variability that do not become apparent in short-term studies, according to a LTER press release.
“Each additional year of LTER data helps us to better understand how ecosystems respond to environmental change,” said Scott Collins, chair of the LTER Executive Board. “Such understanding provides valuable information for federal agencies, land managers and legislators who want to develop responsible policies to deal with a rapidly changing world.”
The April edition of BioScience, published by the American Institute of Biological Sciences, features a package of articles based on findings from LTER sites. Another report identifies biological winners and losers in the cryosphere, the ice-bound regions of the planet, as they are affected by climate change.
The shrinking of the cryosphere has been one of the most widely reported examples of planetary consequence of climate change. “The populations of microbes, plants and animals that depend on the snow and ice will decrease if they are unable to migrate to new areas with ice,” said Andrew Fountain, the lead author of another BioScience article. “But life that previously found the cryosphere too hostile should expand,” he added.
Less snow depth in polar regions could attract animals such as white-tailed deer, elk and caribou — animals that don’t inhabit those areas now because movement through deep snow demands too much energy.
Almost 2,000 scientists and students conduct more than 200 large-scale LTER experiments each year and make their findings freely available online. “The LTER sites are providing transformative information about the causes and consequences of climate and environmental changes to ecosystems,” said David Garrison, the NSF program director for coastal and ocean LTER sites. “These sites are some of our best hopes for providing the sound scientific underpinnings needed to guide policy for the challenges of future environmental change.”
The NSF is an independent federal agency with a congressional mandate to promote the progress of science in the advance of national interests and well-being.