Hill Country Vegetation
When the Hill Country was settled by European man in the mid-1800s, it was maintained as a grassland savannah largely by grazing habits of bison and antelope as well as by frequent natural and man-made fires. The land supported a rich diversity of forbs and grasses. Cedar was restricted to overgrazed areas along rivers and streams, and in areas of shallow soils and steep canyons where fires did not occur frequently. White-tailed deer were rarely found in the grasslands. With European settlement came fences, cows, sheep, goats and the control of fire. Livestock were continuously grazed in fenced pastures which disrupted the natural movement patterns of grazing animals. Plants were not allowed to rest and recover from grazing. By 1900, continuous overgrazing and control of fire had taken its toll. The land began to change from a grassland to a brushland. Many of the woody brush species were readily grazed by sheep, goats, cattle, and an increasing deer herd. These animals have selective eating habits and eat the more desirable plants first and leave the less desirable plants for last. By the 1940's, many of the good quality plant species were highly depleted and not readily found on most ranges. The Hill Country was now dominated by poor quality browse, forb, and grass plants. Ashe juniper (commonly called cedar) is a highly undesirable forage plant avoided by both domestic livestock and deer. In much of the Hill Country, cedar became the dominant plant species causing a once diverse and healthy landscape to become a "cedar break" with very little plant diversity or vigor.
Wildlife Managers often speak of vegetation in terms of grasses, forbs (weeds and wildflowers), and browse (leaves and stems of woody plants). In the Texas Hill Country, we often speak of vegetation in terms of white-tailed deer food. We take this approach simply because white-tailed deer have such a tremendous impact on vegetative communities. As an indication of ecosystem health, we like to see a wide variety of good deer foods on all properties we visit. High plant diversity equals high animal diversity. Unfortunately, we often see low plant diversity and most sites are dominated by poor-quality deer foods (e.g., cedar, persimmon, and prickly pear). The primary reason for this is that there are too many animals (white-tailed deer, exotic ungulates, livestock) on the range and not enough groceries. As a result, white-tailed deer are forced to eat foods on which they cannot survive. When we see deer populations declining from malnutrition, we also see a decline in the number of turkey, quail, dove, songbirds, reptiles, and other mammals. Basically, the overall ecosystem is suffering.
By monitoring vegetation in terms of white-tailed deer foods, wildlife managers can assess ecosystem health. By the way, plants preferred by white-tailed deer are also preferred by exotic ungulates (e.g., axis deer, fallow deer, sika deer, aoudad), as well as domestic sheep and goats. Deer prefer forbs when they are available, and as they become unavailable deer shift their diets to browse plants. This usually occurs in the summer and fall period. During the late summer and fall, mast (acorns, berries, and fruits) from browse plants can play an important role in deer diets. Grasses do not play a major role in deer diet and generally comprise only a small percent of their annual diet. When deer do utilize grass, the plant is in a young and succulent growth stage, and forbs and browse plants are not readily available. Healthy ecosystems will consist of high plant diversity, structural diversity (grasses and forbs, low growing shrubs, trees), good ground cover, and will not have a prominent browse line.
Download Vegetation of the Kerr Wildlife Management Area and its Preference by White-tailed Deer(PDF 1.4 MB). As the title implies, this document includes a plant list of species (grasses, forbs, and browse) found on the Kerr Wildlife Management Area (WMA). Each plant is ranked by its preference to white-tailed deer. The plant communities found on the Kerr WMA are representative of plant communities that could be found throughout much of the Hill Country, where sound ecosystem management programs are implemented. As a general rule of thumb, the more highly-preferred (by deer) plants found on your property, the healthier your rangeland.