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---------------------------- Original Message ----------------------------
Subject: Building a New Desert Science
From:    "ARS News Service" <NewsService@ars.usda.gov>
Date:    Thu, May 24, 2007 7:51 am
To:      "ARS News subscriber" <gordonse@one.net>
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STORY LEAD:
A Framework for Building New Desert Science
___________________________________________

ARS News Service
Agricultural Research Service, USDA
Don Comis, (301) 504-1625, donald.comis@ars.usda.gov
May 24, 2007
--View this report online, plus photos and related stories, at
www.ars.usda.gov/is/pr ___________________________________________

Agricultural Research Service rangeland scientist Jeff Herrick has joined
with scientists from around the world to develop a template for a new
desertification science that incorporates human as well as biological and
physical dimensions.

Herrick is at the ARS Jornada Experimental Range near Las Cruces, N.M. The
experimental range includes 193,000 acres of rangeland in the Chihuahuan
Desert.

Herrick and colleagues in environmental and social sciences from around
the world have written a paper on the subject entitled "Global
Desertification: Building a Science for Dryland Development." It was
published earlier this month in Science magazine.

The researchers introduced the Drylands Development Paradigm (DDP), named
for a 2001 workshop in Berlin, Germany, from which the original framework
for solutions to desertification was developed.

Two of the principles of this framework have guided ARS work at the
Jornada for many years: that slow variables determine what happens on arid
lands, and that these slow variables are often associated with tipping
points or thresholds that, if crossed, can rapidly lead to irreversible
change.

Experience at the Jornada taught Herrick that arid regions work on "desert
time," in which recovery is often initiated by rare events, like unusually
large rainstorms. One of the ways this knowledge can be used is by staking
seed-filled plastic pipes in dry rills. When rain comes, runoff flows
through the pipe, depositing seeds under a layer of litter “mulch” and
beginning the slow process of vegetation recovery.

Experience also taught Herrick that natural ecological processes dictate
that once a threshold--such as too much weedy brush growth--is reached, it
can be very difficult to reverse.

Part of the DDP involves integrating local and scientific knowledge to
anticipate thresholds long before they are reached, while they still can
be reversed.

It is a framework for actions to support the United Nations' efforts to
combat desertification worldwide, recognizing that about 250 million
people in the developing world live in arid lands with some form of severe
land degradation.

ARS is the U.S. Department of Agriculture's chief scientific research agency.

___________________________________________

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__________________________________________
ARS News Service, Information Staff, Agricultural Research Service 5601
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