The primary business of U.S. Army Yuma Proving Ground is testing weapon systems and munitions, work that takes place in the great outdoors.

Some might presume, incorrectly, that the interior of the proving ground is a pulverized waste land, permanently contaminated with unexploded artillery projectiles and the noxious residue of gunpowder. This is far from the truth.

Though firing takes place each workday, it is carefully controlled and restricted. Artillery pieces, mortars, tank guns, and every other weapon system fires into defined impact areas using designated lines of fire. Electronic data gathering equipment tracks the flight of each shell, as do human observers. Many missiles and other projectiles are recovered after impact, for developers need them to fully analyze test results.

As the Army's extreme environment test expert, it is useful to think of the proving ground's landscape as a natural laboratory. YPG's people have a vested interest in preserving the desert and all of its flora and fauna. In fact, some of the best preserved areas of Southwest Arizona's precious Sonoran Desert are located within the proving ground's boundaries.

The people within YPG's Environmental Sciences Division work closely with testers to sustain the integrity of the proving ground's ranges into the future. The desert is fragile, with little rainfall and sparse vegetation. For example, when a vehicle drives off-road and breaks through a thin crust of desert pavement, called malapais, tire tracks remain almost forever. Even worse, inches of now-exposed fine grain soil that lie beneath the crust can easily be blown by the wind or eroded during wind and rain storms.

"In the desert, vehicle tracks attract additional traffic and, before you know it, you have an ad hoc road," said Daniel Steward, wildlife biologist. "Off road travel can be very damaging to the environment and dangerous on an active military installation. There are plenty of areas throughout the desert southwest where you still see obvious evidence of training from World War II. Maintaining a small footprint is the most effective strategy for minimizing impacts to natural and cultural resources." He goes on to say that being responsible saves the government money and sustains YPG's testing capability.

Steward's area of expertise is managing wildlife, which he says must be performed from an eco-system perspective. This means developing plans that encompass all parts of the environment -- nutrients deriving from the soil, energy coming from the sun, plant life producing the foods animals consume, as well as the entire food chain. A huge amount of interaction occurs among these elements -- things that eat other things, things that control things from eating other things -- truly a complicated web.

"When mankind disrupts one part, unintended consequences can result somewhere along the chain," he said.

The non-native salt cedar trees common in the Yuma area provide an excellent example of the fruits of "unintended consequences." The trees were brought here in the late 1800s. Salt cedars obviously liked the area, for they grew and prospered. Unfortunately, these trees drink copious amounts of water and deposit salts in the soil, displacing native species and often damaging the landscape. Along the Colorado River, prolific salt cedar and other invasive growth have created impenetrable barriers that prevent native animals from reaching life giving water and altering the soil chemistry such that native plants cannot thrive.

Steward is quick to note that the workers at YPG are often fascinated by the environment and knowledgeable about it.

"Folks are proud of where they work and take pride in working in a beautiful desert," he said. "Test personnel often tell me about amazing wildlife sightings and interactions downrange that you would expect to see televised on the Discovery Channel."

The goal of YPG's Environmental Sciences Division is to actively support the proving ground's test mission by aiding in the planning of test projects while complying with federal, state and local environmental regulations. YPG must be responsive to often unique test requirements, and environmental personnel help identify solutions that minimize the footprint on the environment and are cost effective at the same time.

"Some test programs are unbelievably complex with lots of moving parts," said Steward. "But I have found that we can always put our heads together with test officers to develop a solution to any problem that comes up."