Hill Country Wildlife Management
The border above illustrates 5 basic tools (axe, cow, plow, fire, and gun) used for managing wildlife communities. The key to managing natural resources is to use a holistic approach, where all of these Tools are applied to develop and maintain healthy ecosystems. Single species deserve less attention, while the system in which they thrive requires more. Knowing how that system functions, and applying the techniques with which that system developed (e.g., moderate cattle grazing, prescribed burning, hunting) is imperative for its continued existence.
As discussed in Historical Perspective, the expansion of Ashe juniper (cedar) has had a tremendous impact on the ecosystem, causing a decrease in plant species diversity and an increase in soil erosion. Cedar brakes lose a significant amount of precipitation through transpiration and overland flow, leaving much less water for aquifer recharge.
Landowners have been cutting cedar for years, and continue to find out that one treatment is good for only a few years. Ashe juniper, or blueberry juniper, which is found throughout the eastern and central Hill Country, dies when the tree is cut. However, since the soil is full of juniper seeds, the landscape is due for another treatment after 7-8 years. Redberry juniper, located in western Hill Country, resprouts from the root system after the tree is cut. Thus, treatment of this variety is necessary at more frequent intervals.
Initial treatment of cedar stands requires mechanical control. For years, cedar was removed by pushing (with bulldozers), and chaining. Such methods can be quite destructive since this region of Texas has such shallow and rocky soils. As trees are pushed over, rocks are usually pushed to the surface, leaving no substrate to support ground cover. As a result, remaining soil is washed away and only rocks remain. Generally, you can expect 50,000 years to pass before the rocks turn to soil. As these consequences became more apparent, some turned to hand cutting. While hand cutting allows for selective removal of trees, and causes little or no soil disturbance, it is a very slow and expensive process.
Fortunately, today we have hydraulic shears, which allow for selective removal, minimal soil disturbance, and efficient work. Many claim that they can remove at least as many trees with shears as they can with doziers, in the same period of time. Furthermore, the cost of shearing is no more than the cost of other methods. Rates tend to range from $55-75/acre, and operators cut cut an acre/hour in flat to gently rolling terrain.
Following are some considerations of major importance when planning a brush management program:
- The program should not adversely impact endangered species or their habitat.
- Extreme care should be taken to insure that too much wildlife cover is not destroyed.
- The method used should improve wildlife food supply and habitat.
- Removal of desirable plant species should be minimal.
- The program should be economically feasible and comply with overall goals of the management plan.
- Plant diversity and general health and vigor of the range should be increased.
- Areas which support winter turkey roosts should remain totally intact.
- Treatments that disturb soils should not be applied to highly erodible sites
Bison roamed the Hill Country through mid to late 1800s, leaving quite an impact on the landscape. Historical reports indicate that bison herd were strung-out 90 miles in length, as it took 3 days to travel from one end of the herd to the other. One report mentions that settlers traveling from Fredericksburg to Mason, had to turn back because there was not enough grass left (after the bison moved through) to feed their horses. While such grazing pressure left a lot of tilled soil, resting periods (of the rangeland) were sufficient to allow for rapid responses of annual forbs (weeds & wildflowers) and grasses. Resulting was more plant diversity and more wildlife foods. Bison opened stands of dense grasses, providing more food for deer, turkey, quail, prairie chicken, and songbirds. Undoubtedly, bison grazing was a major force that shaped the ecosystem.
European settlement thrived during the "Golden Period" when grasslands were lush and seemed capable of supporting an unlimited number of livestock (cattle, sheep, goats, oxen, hogs, horses). More normal years followed, when rainfall was scarce and overgrazing was common. This resulted in abused rangelands lacking adequate groundcover and available browse to support healthy livestock and wildlife populations. Midgrass and tallgrass communities were replaced with shortgrass communities. Overgrazing with domestic livestock has continued through the 20th century and many rangelands continue to suffer.
As Aldo Leopold wrote in his 1933 textbook titled Game Management, "...game can be restored by the creative use of the same tools which have heretofore destroyed it - ax, plow, cow, fire, and gun." Leopold often referred to the "cow" as an effective wildlife management tool. Cattle can be used as a tool to manipulate and enhance wildlife habitat and plant diversity (as bison did). The main role of grazing in a wildlife management program is to reduce the quantity of grass, allowing sunlight to reach the lower growing forbs, which are important wildlife foods. Furthermore, this process creates more structural diversity, which is more conducive to nesting, brood rearing, and hiding.
Range improvement can be attained through proper grazing rates and by scheduled rest periods to allow pastures to be free of grazing by domestic livestock. Rotational grazing systems should allow pastures to be rested (deferred) during a specified time of the year. Some examples of grazing options in order of preference are: a short duration or "time control" system; a high intensity - low frequency system (HILF); a 3 pasture-1 herd system, and the 4 pasture-3 herd rotational grazing system. Each requires different degrees of involvement and fencing. Professionals from the Natural Resources Conservation Service (NRCS), Texas Agricultural Extension Service, and/or Texas Parks and Wildlife can discuss the advantages and disadvantages of each system.
Tilling the soil is another approach to setting-back plant succession and promote the growth of desirable wildlife foods (forbs). As mentioned above, bison tilled the soil as they grazed through areas, promoting more plant diversity. While used extensively in other parts of Texas, methods of soil disturbance generally are not recommended in the Hill Country, as the shallow, rocky soils are highly vulnerable to erosion. Food plots are difficult to establish, especially during stressful years when they are most needed. Therefore, wildlife management in the Hill Country typically involves only 4 of the tools, excluding the "plow."
Bison were not the only force shaping the system in which pronghorn antelope, black bear, wolf, white-tailed deer, turkey, quail, and prairie chicken thrived. Fires, natural and man-made, played an integral role in managing that system. Since the 1850s, man has suppressed fire, and the grasslands that were once dotted with an occasional live oak motte have been replaced by parklands and woodlands. Ashe juniper has spread from the steep draws and canyons and exploited the uplands.
A prescribed burn program that is used properly with a grazing deferment program and deer harvest management, is an effective tool for managing wildlife habitat. Burning increases plant quantity and quality, and enhances habitat diversity. Many plant species are tolerant of fire. Others require fire for adequate germination. Cedar is not a fire tolerant plant. It was controlled by the frequent wildfires that occurred before European settlement. Europeans suppressed fire to prevent damage to wooden structures, farmlands, fences, and grazing lands. That eliminated or reduced the role that fire played in maintaining an ecosystem that was not dominated by cedar. Formerly restricted to steep rough areas where fire couldn't reach, cedar is rarely eaten by deer or livestock and quickly invades all sites in the absence of fire. Controlled fire (prescribed burning) reduces regrowth cedar, but rarely harms mature cedar, the home of the endangered golden-cheeked warblers, and encourages the growth of deciduous trees preferred by black-capped vireos.
Burned pastures can be grazed immediately to reduce grasses that compete with forbs, then deferred to allow the pasture to rest. Whitetail and exotic wildlife numbers may have to be reduced prior to burning to allow preferred plants to reestablish following prescribed fire. Portions of the property should be left in permanently unburned cover to insure that plants intolerant of fire are part of the ecosystem diversity. A burning schedule should be maintained to give priority to burning in the winter and early spring before green-up. Even with the best planning, burning "windows of opportunity" always depend on humidity, wind, and fuel moisture. The inexperienced manager should ask for assistance and/or advice from agencies such as TPW or the NRCS. While instructional materials are available, it is suggested that the novice assist on a burn conducted by an experienced person before attempting the first controlled burn.
The period between 1900-1940 saw a growing deer herd with large bodied, well antlered animals. Deer foods were relatively abundant. Around the 1940's, the deer herd overpopulated its range. The combined grazing pressure of too many deer, sheep, goats, and cattle again changed the vegetative patterns of the Hill Country. Thereafter, die-offs began to occur at 5 to 7-year intervals. Every year, the Hill Country loses 20-40% of its white-tailed deer population to malnutrition. As one deer biologist states, "We probably have the best buzzard management program in the world, and we're feeding them white-tailed deer. Mature Hill Country bucks field-dressed around 200 pounds in the early 1900s. Whereas a decent mature buck today weighs around 120 pounds. What's the problem? There are too many deer, and not enough groceries.
Areas with higher deer densities have lower fawn crops, more major die-offs, smaller body weights, and poorer quality antlers. These symptoms are a result of abused rangeland, where white-tailed deer (and often exotic deer and domestic livestock) have eaten all available forbs and browse. Such rangelands have poor plant diversity and are dominated by cedar, persimmon, and prickly pear cactus. Consequently, such areas have poor wildlife diversity. The whole system is suffering, as soil is washed away and more rock is exposed. There is no groundcover to capture runoff, and rain water is lost.
The axe, cow, and fire do little good when deer numbers remain at horrendously high levels. For rangelands to respond to these various management practices, deer must be harvested and maintained at or below the carrying capacity of the land. This recommendation includes (emphasizes) the harvest of antlerless deer (does). For more information, please download White-tailed Deer Management in the Texas Hill Country!(PDF 1.1 MB)
Today, it is very important that land managers understand basic ecological principles of plant succession, plant growth, food chains, and water, mineral and soil nutritive cycles as they affect range, wildlife, and grazing management. In addition we should know and recognize the basic needs and preferences of the livestock and wildlife species for which we are trying to manage. It is equally important to manage for a high level of plant succession and quality wildlife habitat using the basic tools of grazing, rest, fire, hunting, animal impact, disturbance, and technology. This not only produces high quality habitat and animals, but also can lead to more stable conditions during stress periods such as droughts and winter.