Patchwork strategies may be best for restoring Texas rangelands

Dr. Bill Pinchak, Experiment Station range animal nutritionist, and his colleagues, Dr. Jim Ansley, Dr. Dean Ransom and Dr. Richard Teague will explain the patch disturbance for rangeland restoration management plan at the Range and Wildlife Field Day on Oct. 5.

“Managing the Rangeland Resources of the Texas Rolling Plains” will begin with registration at 8 a.m. at Texas Foundation Seed, adjacent to the Texas A&M University System Agricultural Research and Extension Center near Vernon.

Texas rangelands have steadily declined in productivity, biodiversity and watershed function due to “chronic” disturbances, Pinchak said. These continuous disturbances are the primary reason for woody plant encroachment, ecological degradation and loss of plant diversity.

“Rangeland restoration has traditionally been based on chemical, mechanical and/or fire techniques applied to an entire pasture at infrequent intervals,” he said. “These large-scale disturbances have generally created landscapes favorable to livestock management, but not necessarily favoring wildlife, watersheds or ecosystem function.”

Now, Pinchak said, increasing interest in ecotourism, land tenure changes and smaller ranch properties have led to different of what is good rangeland condition.

The Rangeland Innovations for Sustainable Environments team is a group of scientists from the Vernon, Uvalde and San Angelo Research and Extension Centers who are studying the feasibility of re-introducing frequent, small-scale (patch) disturbances.

In addition to Pinchak, Ansley, Teague and Ransom, team members are Dr. Keith Owens, Uvalde; Dr. Butch Taylor, Sonora; Dr. Susan Cooper, Uvalde; and Dr. Dale Rollins, San Angelo.

For the past three years, patch disturbances of fire or mechanical brush control on continuously grazed pastures has been used to alter livestock grazing patterns, Pinchak said.

These changes are anticipated to facilitate aid biodiversity and production, and decrease the effects of woody plants on Texas rangelands under continuous grazing, he said.

Funding for this research initiative is provided by the U.S. Department of Agriculture Joe Skeen Institute for Rangeland Restoration.

Research is being conducted across a 400-mile north to south gradient of Texas rangelands from Vernon to Barnhart and Uvalde, he said. Fire or roller-chopping is applied to 10 percent of each pasture to determine the soil, plant and wildlife responses.

The studies create a mosaic of patch disturbance histories that will alter the timing, duration and intensity of livestock and wildlife use across the entire pasture, Pinchak said.

“The analogy is one of a patchwork quilt, where each color patch in the quilt represents a different understory (grasses) and overstory (trees/shrubs) plant structure based on the type of patch disturbance used, time since disturbance and intensity of livestock and wildlife use on the resultant patch,” he said.

The patches represent: areas recently treated and heavily grazed; those treated and grazed heavily one to seven years ago; areas grazed less than in the past; and areas grazed more than in the past, he said.

Collectively, the patch disturbances increase the diversity of plants and improve the spatial distribution of grazing by livestock and wildlife, Pinchak said.

The scientists believe this technique will lead to improved rangeland condition, because of the natural tendency for livestock and wildlife to use recently disturbed areas, he said. This should decrease use on undisturbed and older disturbed areas and promote more rapid rates of vegetation change.

“We have seen the animals do prefer and utilize more the disturbed sites, although with the drought, the responses have been slow,” Pinchak said.

The practice of disturbing only 10 percent of any one pasture also benefits the producer who doesn't have another place to go with the cattle, he said.

“If a pasture was burned in entirety, it requires pre-burn and post-burn removal of the cattle,” Pinchak said. “With the patch disturbance approach, it allows them to manage woody plants and improve range conditions without having to change their grazing management program.”