Keeping an Edge

Prior to European settlement, the Texas Hill Country was a savanna-like mixture of grasslands, woodlands and shrublands. A little over one hundred years later this landscape is much altered. Overgrazing, overpopulation of deer, erosion and absence of periodic fire all have drastically changed the vegetation patterns. Friedrich Wilderness Park has become densely wooded, with Ashe junipers predominating. Grasslands are now one of the most minimal components of this property. Shrublands are also much reduced.

Several areas of the Park are being managed for grasslands or shrublands. In the western research area of the Park three small sites of about five acres each were cleared several years ago. These sites are being managed as nesting habitat for Black-capped vireo, one of the two endangered bird species present in our area. Early in 1997 prescribed (or controlled) burns were conducted on about one half of each of two of these sites. In early 1998 one half of the third site was burned. Fire is an important natural factor in the formation of shrublands and grasslands. Regeneration of grass and shrub species has been remarkable.

Controlled burn
Photo by Greg Pasztor©

Most of our native woody species of plants, other than Ashe juniper, are fire adapted; after a burn the plants sprout again from the roots. Thick clumps of vigorous, new shrubby growth are apparent on the site. This is the primary vegetation structure necessary for Black-capped nesting sites. Little bluestem is now abundant on the burned portions of these sites. Two other climax grasses, Big bluestem and Indiangrass had not been previously recorded in the Park’s flora. Both of these two species have appeared in the treated sites. This Autumn they bloomed, hopefully producing seed to further populate the sites. The sites will continue to be managed on a ten year rotation of controlled burning.

The lower, eastern portion of the Park has many small, remnant pockets of grasslands. Little bluestem is often evident. These areas are now being managed by removal of invading woody species, mainly Ashe juniper. In the future, a goal is to also apply prescribed burning to some of these areas.

Restoring the grasslands and shrublands of Friedrich Wilderness Park also increases the amount of "edge." Edge is an ecological concept signifying the zone where two communities intersect. The edge combines species of plants and animals from both communities. In addition there are usually species that prefer this transition zone. Thus the edge is richer in diversity than either of the two communities it joins.

As the grasslands and shrublands of Friedrich Wilderness Park are restored an the edge effect increased, we are seeing an overall increase in biotic diversity. The increased grasses and other herbaceous plants will support herbivores such as grasshoppers, field mice and cottontail rabbits. These in turn will support predators such as reptiles, hawks and foxes. This is a greatly simplified illustration. The actual changes will range from microscopic bacteria to large mammals.

To ensure maximal diversity of plant and animal species and overall ecological health of Friedrich Wilderness Park we must implement management programs. Nature preserves are not areas to be set aside and left alone. Due to previous and continuing impacts to our ecosystems, we must counterbalance negative effects through management. Conservation at Friedrich Wilderness Park will be an increasing challenge as the surrounding areas are developed and altered. Adjoining habitat will be degraded and fractured. Increasing numbers of foreign plant species will be introduced to the Park from gardens and disturbed areas. Exotic animals, primarily cats and dogs, will impact wildlife. Management is our best defense in preserving Friedrich Wilderness Park as a biological preserve.