Study shows woody plant encroachment has increased stream flow in the Edwards Plateau

Mar 04, 2010

A new study by Texas AgriLife Research scientists finds that contrary to widespread perceptions, springs in the Edwards Plateau, which provide much of the stream flows, have not been declining as a result of increased encroachment of woody plants. In fact, spring flows are twice as high as they were prior to 1950.

The study found that the landscape is actually recovering from intensive livestock grazing in Texas that dates back to the late 1800s. Large numbers of cattle, sheep and goats continuously grazing rangelands led to widespread soil degradation, partly hindering the amount of water recharging springs and groundwater, said Dr. Bradford Wilcox, a professor in the Department of Ecosystems Science and Management at Texas A&M University and one of the authors of the study, which is to be published in the journal Geophysical Research Letters, a publication of the American Geophysical Union.

"The study took place in the Edwards Plateau region of Central Texas, the primary water source for the Edwards Aquifer, which provides water for San Antonio and numerous smaller municipalities," he said. "This area was basically converted from grassland to a shrubland after many years of heavy livestock grazing. What people have forgotten is that in the time period between healthy grasslands and the current shrublands, there was an extended period when the land was quite degraded. Subsequent to 1960, livestock numbers have declined and the landscape has recovered although there are now more cedar than in the past."

From 1880 to 1900, there were more animals on the land than it could support. In fact, for a short period of time, stocking rates at the turn of the last century were 10 times greater than current levels, Wilcox said.

However, as fewer cattle and other livestock were used on the land as part of agricultural production since the late 1900s, the region has gone through revitalization.

"As a result, these landscapes are recovering, but they've also converted to woody plants," he said. "We're also seeing large-scale increases in the amount of spring flows. This is opposite of what everybody is presuming - the trees are there and they are sucking up all of this water. The trees are actually allowing the water to infiltrate. There's is a broad perception that the trees are making these natural springs disappear. This is definitely not the case."

The results of the study suggest that the Edwards Aquifer recharge is "higher than it used to be."

"I think the results from this study are pretty strong evidence that this is the case," Wilcox said.

Wilcox said what hasn't been researched is if woodlands were restored back to well-managed savannas, if there might be further increases in spring flow.

The increasing spring flows should be seen as evidence that well-managed rangelands can result in an increase in recharge and spring flow, he said.

Explore further: Image: Grand Canyon geology lessons on view

Provided by Texas A&M AgriLife Communications

5 /5 (2 votes)
add to favorites email to friend print save as pdf

Related Stories

Climate change could dramatically affect water supplies

Dec 17, 2008

(PhysOrg.com) -- It’s no simple matter to figure out how regional changes in precipitation, expected to result from global climate change, may affect water supplies. Now, a new analysis led by MIT researchers has found ...

Management practices key to watershed condition

Jul 15, 2008

Animals thrive on the banks of waterways. And those same tree-covered, green grassy areas are keys to maintaining healthy watersheds for creeks and rivers. Landowners must learn how to manage these properties to strike an ...

Recommended for you

Six Nepalese dead, six missing in Everest avalanche

2 hours ago

At least six Nepalese climbing guides have been killed and six others are missing after an avalanche struck Mount Everest early Friday in one of the deadliest accidents on the world's highest peak, officials ...

Clean air: Fewer sources for self-cleaning

16 hours ago

Up to now, HONO, also known as nitrous acid, was considered one of the most important sources of hydroxyl radicals (OH), which are regarded as the detergent of the atmosphere, allowing the air to clean itself. ...

There's something ancient in the icebox

16 hours ago

Glaciers are commonly thought to work like a belt sander. As they move over the land they scrape off everything—vegetation, soil, and even the top layer of bedrock. So scientists were greatly surprised ...

Image: Grand Canyon geology lessons on view

23 hours ago

The Grand Canyon in northern Arizona is a favorite for astronauts shooting photos from the International Space Station, as well as one of the best-known tourist attractions in the world. The steep walls of ...

First radar vision for Copernicus

Apr 17, 2014

Launched on 3 April, ESA's Sentinel-1A satellite has already delivered its first radar images of Earth. They offer a tantalising glimpse of the kind of operational imagery that this new mission will provide ...

User comments : 0

More news stories

Six Nepalese dead, six missing in Everest avalanche

At least six Nepalese climbing guides have been killed and six others are missing after an avalanche struck Mount Everest early Friday in one of the deadliest accidents on the world's highest peak, officials ...

China says massive area of its soil polluted

A huge area of China's soil covering more than twice the size of Spain is estimated to be polluted, the government said Thursday, announcing findings of a survey previously kept secret.

There's something ancient in the icebox

Glaciers are commonly thought to work like a belt sander. As they move over the land they scrape off everything—vegetation, soil, and even the top layer of bedrock. So scientists were greatly surprised ...

Clean air: Fewer sources for self-cleaning

Up to now, HONO, also known as nitrous acid, was considered one of the most important sources of hydroxyl radicals (OH), which are regarded as the detergent of the atmosphere, allowing the air to clean itself. ...

Scientists tether lionfish to Cayman reefs

Research done by U.S. scientists in the Cayman Islands suggests that native predators can be trained to gobble up invasive lionfish that colonize regional reefs and voraciously prey on juvenile marine creatures.

Leeches help save woman's ear after pit bull mauling

(HealthDay)—A pit bull attack in July 2013 left a 19-year-old woman with her left ear ripped from her head, leaving an open wound. After preserving the ear, the surgical team started with a reconnection ...