Featured Research

from universities, journals, and other organizations

Deserts Still Damaged 30 Years After Minimal Disturbance

Date:
March 11, 1999
Source:
University Of Arkansas
Summary:
Forget the damage done by mountain bikes and all-terrain vehicles -- a University of Arkansas researcher has found that sometimes leaving only footprints can wreak long-term ecological havoc on Western U.S. deserts.

FAYETTEVILLE, Ark. -- Forget the damage done by mountain bikes and all-terrain vehicles -- a University of Arkansas researcher has found that sometimes leaving only footprints can wreak long-term ecological havoc on Western U.S. deserts.

Dr. Dave Evans, biology professor at the University of Arkansas, and Jayne Belnap of the U.S. Geological Survey, study the black biological soil crust that blankets Western deserts. The barely visible dark material teems with life, harboring lichens, mosses, cyanobacteria and algae.

People have traditionally viewed the desert as a wasteland. Historically ranchers used the dry, apparently barren landscape to raise cows. Today city dwellers use the vast land tracts as playgrounds, riding mountain bikes or all-terrain vehicles across the arid landscape.

Such behavior may alter these areas and the species that live there permanently, even if the behavior stops, according to Evans and Belnap.

The researchers report their findings in the January issue of Ecology.

The scientists studied two spots in the Needles District in Utah's Canyonlands National Park -- one where cattle grazed more than 30 years ago and one where their hooves touched the ground eight years ago. Both areas have remained undisturbed since.

"The sites used in our study don't look that different until you get up close and look at the crust," Evans said. "We have other sites that are heavily disturbed and they look very different. The crust is missing and you get mostly cheatgrass."

Evans and Belnap used a round, fluted instrument called a soil corer to take small samples of the desert earth. They measured the nitrogen content of the soil and the ratio of two nitrogen isotopes in the soil, 14N and 15N.

The nitrogen content in soil is a balance between nitrogen added through fixation and nitrogen lost through gas emissions. Evans likens the process to a bathtub with both the faucet and the drain open. Water comes in from the faucet (nitrogen fixation) and leaves through the drain (gaseous emissions). In an undisturbed area, the addition and loss of nitrogen are balanced, and the nitrogen level stays the same. But in areas where plant life has disappeared, less nitrogen gets fixed, causing a net nitrogen loss in the ecosystem.

At eight years and even after 30 years, the Canyonlands areas still show profound nitrogen loss, Evans said. Furthermore, the proportion of 15N in the soil has increased, because 14N leaves the soil more readily. This will ultimately lead to less fertile soil and fewer plants, Evans said. Evans likens the urgency in protecting deserts to that of saving the rain forests.

"Arid ecosystems are the most widespread on earth," Evans said. "The problem is that much of the land has been disturbed so the crusts just aren't that obvious to people."

With about45 percent of the earth's land surface area designated arid or semi-arid and 35 percent deemed at risk of becoming desert, preserving plant life in these areas becomes a crucial component in global climate and environmental issues.


Story Source:

The above story is based on materials provided by University Of Arkansas. Note: Materials may be edited for content and length.


Cite This Page:

University Of Arkansas. "Deserts Still Damaged 30 Years After Minimal Disturbance." ScienceDaily. ScienceDaily, 11 March 1999. <www.sciencedaily.com/releases/1999/03/990311055829.htm>.
University Of Arkansas. (1999, March 11). Deserts Still Damaged 30 Years After Minimal Disturbance. ScienceDaily. Retrieved July 23, 2014 from www.sciencedaily.com/releases/1999/03/990311055829.htm
University Of Arkansas. "Deserts Still Damaged 30 Years After Minimal Disturbance." ScienceDaily. www.sciencedaily.com/releases/1999/03/990311055829.htm (accessed July 23, 2014).

Share This




More Plants & Animals News

Wednesday, July 23, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Michigan Plant's Goal: Flower and Die

Michigan Plant's Goal: Flower and Die

AP (July 22, 2014) An 80-year-old agave plant, which is blooming for the first and only time at a University of Michigan conservatory, will die when it's done (July 22) Video provided by AP
Powered by NewsLook.com
San Diego Zoo Welcomes New, Rare Rhino Calf

San Diego Zoo Welcomes New, Rare Rhino Calf

Reuters - US Online Video (July 21, 2014) An endangered black rhino baby is the newest resident at the San Diego Zoo. Sasha Salama reports. Video provided by Reuters
Powered by NewsLook.com
Shark Sightings a Big Catch for Cape Tourism

Shark Sightings a Big Catch for Cape Tourism

AP (July 21, 2014) A rise in shark sightings along the shores of Chatham, Massachusetts is driving a surge of eager vacationers to the beach town looking to catch a glimpse of a great white. (July 21) Video provided by AP
Powered by NewsLook.com
$23.6 Billion Awarded To Widow In Smoking Lawsuit

$23.6 Billion Awarded To Widow In Smoking Lawsuit

Newsy (July 20, 2014) Cynthia Robinson claims R.J. Reynolds Tobacco Company hid the health and addiction risks of its products, leading to the death of her husband in 1996. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins