Impact of warming climate doesn't always translate to streamflow

Apr 06, 2012

An analysis of 35 headwater basins in the United States and Canada found that the impact of warmer air temperatures on streamflow rates was less than expected in many locations, suggesting that some ecosystems may be resilient to certain aspects of climate change.

The study was just published in a special issue of the journal BioScience, in which the Long-Term Ecological Research (LTER) network of 26 sites around the country funded by the National Science Foundation is featured.

Lead author Julia Jones, an Oregon State University , said that increased significantly at 17 of the 19 sites that had 20- to 60-year , but streamflow changes correlated with temperature changes in only seven of those study sites. In fact, water flow decreased only at sites with and ice, and there was less impact in warmer, more arid ecosystems.

"It appears that ecosystems may have some capacity for resilience and adapt to changing conditions," said Jones, a professor in OSU's College of Earth, Ocean, and Atmospheric Sciences. "Various may contribute to that resilience. In Pacific Northwest forests, for example, one hypothesis is that trees control the stomatal openings on their leaves and adjust their water use in response to the amount of water in the soil.

"So when presented with warmer and drier conditions, trees in the Pacific Northwest appear to use less water and therefore the impact on streamflow is reduced," she added. "In other parts of the country, forest regrowth after past logging and hurricanes thus far has a more definitive signal in streamflow reduction than have warming temperatures."

LTER sites were established to investigate over long temporal and broad spatial scales throughout North America, including the H.J. Andrews Experimental Forest in Oregon, as well as sites in Alaska, New Mexico, Minnesota, New Hampshire, Georgia, Puerto Rico, Antarctica and the island of Moorea. Not all were part of the BioScience study.

In that study, warming temperatures at some of the headwater basins analyzed have indeed resulted in reduced streamflow due to higher transpiration and evaporation to the atmosphere. But these changes may be difficult to perceive, Jones said, given other influences on streamflow, including municipal and agricultural water usage, forest management, wildfire, hurricanes, and natural climate cycles.

"When you look at an individual watershed over a short period of time, it is difficult to disentangle the natural and human-induced variations," Jones said, "because hydrologic systems can be quite complex. But when you look at dozens of systems over several decades, you can begin to gauge the impact of changing vegetation, climate cycles and trends.

"That is the beauty of these long-term research sites," she said. "They can provide nuanced insights that are crucial to effective management of water supplies in a changing world."

Jones said the important message in the research is that the impacts of are not simple and straightforward. Through continuing study of how ecosystems adapt to changing conditions, resource managers may be able to adapt policies or mimic natural processes that offer the most favorable conditions for humans and ecosystems to thrive.

Explore further: Fish will have to find new habitats or perish if global warming is left unchecked

Related Stories

Managing future forests for water

Sep 28, 2011

Forest Service Southern Research Station (SRS) scientists recently used long-term data from the Coweeta Hydrological Laboratory (Coweeta) in Western North Carolina to examine the feasibility of managing forests ...

Research: Climate change affecting mussel survival

Sep 02, 2010

(PhysOrg.com) -- Warmer air and water temperatures along the U.S. East Coast are shrinking the geographic region where blue mussels can survive, according to findings by University of South Carolina researchers published ...

In forests, past disturbances obscure warming impacts

Mar 05, 2012

Past disturbances, such as logging, can obscure the effects of climate change on forest ecosystems. So reports a study just published in the Proceedings of the National Academy of Sciences. The paper, explor ...

Recommended for you

Gimmicks and technology: California learns to save water

10 hours ago

Billboards and TV commercials, living room visits, guess-your-water-use booths, and awards for water stinginess—a wealthy swath of Orange County that once had one of the worst records for water conservation ...

Cities, regions call for 'robust' world climate pact

10 hours ago

Thousands of cities, provinces and states from around the world urged national governments on Thursday to deliver a "robust, binding, equitable and universal" planet-saving climate pact in December.

Will climate change put mussels off the menu?

10 hours ago

Climate change models predict that sea temperatures will rise significantly, including in the tropics. In these areas, rainfall is also predicted to increase, reducing the salt concentration of the surface ...

As nations dither, cities pick up climate slack

22 hours ago

Their national governments hamstrung by domestic politics, stretched budgets and diplomatic inertia, many cities and provinces have taken a leading role—driven by necessity—in efforts to arrest galloping ...

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.