PARENT SESSION
Oral Session #61: Arid Lands Restoration.
Presiding: S. Loftin
Wednesday, August 7. 1:00 PM to 4:45 PM. Mohave Meeting Room, TCC.
Restoring degraded rangelands in Big Bend National Park.
Sirotnak, Joe*,1, Biggam, Pete2, 1 Big Bend National Park, Big Bend N.P., TX2 Natural Resources Program Center, Denver, CO
ABSTRACT- Endless miles of grassland greeted the early settlers in the area that became Big Bend National Park. A century later, the large expanses of native grasslands are gone. Here and there, patches of grass maintain a tenuous hold in miles of creosote bush and other desert scrub. Once, herds of pronghorn raced across these flats, desert bighorn sheep entered the valley to visit springs, and Mexican gray wolves worked the area in search of prey. Now, all are gone. What happened to cause such a dramatic change? More importantly, can the grassland be restored, or is the area destined to become a landscape of modern badlands. A recent assessment in the northern portion of the park found over 100 water diversions and almost that many stock ponds left over from the ranching days. These structures, in addition to loss of grass cover from overgrazing have altered increased overland flow and concentrated runoff, resulting in over 1000 acres of gully systems, which are gradually eroding into the few remaining patches of native grasslands. Large areas of bare soil have dead and dying creosote. Until recently the creosote was thought to be declining due to loss of infiltration due to the loss of the grass cover. However, new information indicates that severe nutrient imbalances in the soil may be the cause.
KEY WORDS: erosion, desert grassland, hilaria mutica