Chapter 5: Vegetation Management and Wildlife Habitat
Anchor: #CHDHBAEESection 1: Overview
Anchor: #i999711Background
More than 800,000 acres of roadsides associated with Texas highways are vegetated. Most of these acres will be under vegetation management level 2 (as described in Chapter 1). These rights of way include all ecological regions of Texas and represent a cross-section of the state’s varying landscapes. They range from humid prairies and forests in the southeast and east to desert shrub, grassland and forests in the mountainous region of west Texas.
These landscapes support more than 900 species of wildlife and about 5,500 species of vascular plants including 2,000 different wildflowers. Because roadsides within these landscapes provide habitat for a wide variety of plants and wildlife, they are vital to their continued existence.
This section explains why the rich natural resource heritage found along roadsides should be conserved and managed as a part of the Texas highway system.
Anchor: #i999735Threat of Habitat Degradation
Habitat degradation and loss is now the most significant problem associated with maintaining healthy populations of wildlife and plant resources. The adverse effects of habitat destruction have become a national and global concern.
Anchor: #i999745Extent of Habitat Degradation
More than one-half of the wetland habitats in the continental United States have disappeared. Land use changes have resulted in similar losses of coastal wetlands in Texas. Almost two-thirds of hardwood bottomlands (one of the more important habitats) are now gone. In the lower Rio Grande Valley, more than 95 percent of native brush has vanished. Native longleaf pine forests have declined from an estimated six million acres to less than one million acres. Some 95 percent of the originally occurring native prairies have also disappeared.
Remaining habitats have suffered too. Human development has fragmented them. Poor land management practices have modified them. And the introduction of exotic plants and animals has displaced native species.
Anchor: #i999760Significance of Roadsides
As native wildlife and plant habitats continue to decline, those that do remain gain importance. Remaining habitats are important both to the resources dependent on them and to the public. Increasingly, the public views natural resources as part of our Texas heritage. Thus roadsides, through their permanence and statewide distribution, have gained importance as plant and wildlife habitat.