Grasses of the Texas Hill Country: A Field Guide

Introduction

Introduction Area of Coverage The study area of this book encompasses a large portion of nineteen west central Texas counties popularly known as the “Texas Hill Country.” This region encompasses some 24 million acres geographically situated around the Edwards Plateau. This unique and well-defined region is special to many Texans for its history, agribusiness economy, scenic beauty, natural wildlife, and exceptional recreational enjoyment. The book covers the geographic area as illustrated below. This region includes the land within the area roughly bordered by Interstate Highway 35 on the east, U.S. Highway 90 Figure 1. Texas Hill Country area of study. 4 introduction on the south, Texas Highway 29 on the north, and Texas Highway 55 and U.S. Highway 377 on the west. The study area includes all or a portion of the following Texas counties: Bandera Kimble Bexar Llano Blanco Mason Burnet Medina Comal Real Edwards San Saba Gillespie Travis Hays Uvalde Kendall Williamson Kerr This area is largely rangeland. Its mixture of vegetation supports herds of cattle, sheep, and goats. Cultivation is relatively confined to the soils deposited along narrow streams and some valleys. Sorghum, peaches, and wine grapes are important products of the area. The Hill Country also supports the largest white-tailed deer population in North America. Deer hunting and big game wildlife production has become of major economic importance. Large herds of exotic species including axis, sika, and fallow deer; blackbuck antelope; and mouflon rams and aoudad sheep are now managed for sport hunting, creating immeasurable annual revenues. In recent decades, many weekend or vacation properties and sporting lands have been developed throughout the Hill Country. Some are only a few acres in size; others are thousands of acres. These properties often modify traditional land use and conservation practices. Each land is unique in its needs. While some property owners are knowledgeable about land stewardship and practice good conservation, preservation, and restoration practices, some do not. The Edwards Plateau is geologically unique. Deeply dissected limestone hillsides, broad, undulating divides, and stony plains establish diversity in range habitats. The soils are usually shallow yet fertile and vary from sand to clay and are frequently calcareous in origin. The central portion in Llano and Mason counties contains nearly 1.5 million acres of the granite and sandy soils mixture known as the Central Basin. The western portion of the area is comprised of the semiarid Stockton Plateau. Bordered on its eastern and southern sides, the Balcones Escarpment forms a visible boundary of the Edwards Plateau, roughly following Interstate Highway 35 and U.S. Highway 90. Originally, the Hill Country was native grassland and open savannahtype plains with brushy species found introduction 5 along the hillsides and streams. The “big four” grasses of the American tallgrass prairies—big bluestem, little bluestem, yellow indiangrass, and switchgrass—are still common in areas having good soil moisture. Throughout the Hill Country, as in other parts of the state, smaller ecological sites exist, each with its unique capability to produce different plant populations. Some are mesic and some more arid, each supporting its own blend of plant communities. In the more arid areas of the Hill Country , shorter, more drought-resistant grasses such as sideoats grama, Texas Figure 2. A typical landscape of tallgrass and mixed shortgrass species of the Texas Hill Country . The area is commonly rolling calcareous limestone hills with abundant shin oak and juniper shrubs. The predominant grasses seen here include Lindheimer muhly, yellow indiangrass, switchgrass, sideoats grama, and little bluestem. 6 introduction grama, and buffalograss are better adapted than the tall, “big four” grass species. The principal grasses of the clay loam soils include cane bluestem, silver bluestem, little bluestem, sideoats grama, hairy grama, yellow indiangrass , plains lovegrass, and others. The Stockton Plateau supports short- to midgrass mixed species, including cane bluestem, little bluestem , sideoats and hairy gramas, common curly-mesquite, buffalograss , fall witchgrass, tridens, and elymus. Throughout the Hill Country, rocky areas support grass populations under a canopy of the live oak, shin oak, juniper, and mesquite that dominate the woody vegetation. These woody species have invaded to the point that they require specific control as part of the range management process. In addition, many species of cacti, yucca, and other succulents are common. The Texas Hill Country is well known botanically. The earliest professional botanical collections were those of Jean Louis Berlandier and the notable Texas botanist Ferdinand Lindheimer. Lindheimer collected in...