Sabo added that climate change is going to have a hand in frequency and intensity of the floods and droughts of coming years.
"Climate is giving us a new set of operating terms to work with," Sabo said. "We will experience overall drying and great weather variability, both of which will further shorten river food chains.
"There will be drying in some regions, particularly along the equators and increased flow in some rivers, primarily at higher latitudes," Sabo explained. "We will see more variability because there will be change in the seasonality of storms, ocean currents are changing and the way the ocean blows storms to us is going to be different. Drying and more variable flows are coming."
"In some places, like the Southwest U.S., we will get a double punch," he added. "As the streams dry, they also will become more variable in that as rain falls it will race over the parched ground, causing flooding"
The human effect on rivers and streams and the food chain they support are closely tied to land use change, such as water diversion and regulation of flows due to dams.
Sabo outlined a classic scenario that humans face during drought years. As drought takes hold, the need for water for irrigation and other agricultural purposes increases and leads to a draw down of natural river flow. The effects downstream can be devastating. Natural drying through drought is not a human effect, but withdrawal of river water during a drought is, and it can have long-term consequences.
"We would not have guessed that infrequent drought would have had a big effect on the stream, but our results shows that it does," Sabo said. "River and stream water draw-down has a lasting effect."
"We found that some streams affected by drying 5 to 10 years ago, are
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Arizona State University