Shallow 23-30" PZ

Description

The Midgrass Prairie Community (1.1) is the interpretive plant community for the site. It was a fire induced midgrass prairie with scattered tallgrasses, scattered woody plants and a good variety of forbs. The tallgrasses usually occurred in the vicinity of limestone outcrops, drainages or the crests of hills. Live oak, hackberry and elm trees were widely scattered in draws. The Midgrass Prairie Community produces from 1500 to 3000 pounds of biomass annually.

The Mixed-grass Prairie Community (1.2) is midgrass dominated grassland being encroached by indigenous or invading woody species. Numerous woody species, including juniper and mesquite, are increasing in density because overgrazing by livestock has reduced grass cover, exposed some soil and reduced fine fuel for fire. In this phase, the increasing woody species are generally less than four feet tall and still subject to control or suppression by fire and prescribed grazing management. The woody canopy varies between 5 and 15 percent depending on severity of grazing, time since burned and availability of invading species. The preferred tallgrasses are being replaced by the more grazing resistant midgrasses although little bluestem often persists. Important grasses are sideoats grama, tall and meadow dropseed, vine mesquite, plains lovegrass, Texas cupgrass and Arizona cottontop. Texas wintergrass and buffalograss generally increase. Most of the climax perennial forbs persist, but in lesser amounts, being replaced by weedy forbs. Annual primary production ranges from 1000 to 3000 pounds per acre.

Submodel

Description

The Shortgrass/Mixed-brush Community (2.1) presents a 15 percent or greater woody plant canopy of mixed-brush, including oak, mesquite and juniper as the dominant species. There is a continued decline in diversity of the grassland component and an increase in woody species and unpalatable forbs. All, except the more palatable woody species, have increased in size. Mesquite is an early increaser throughout the MLRA. Ashe juniper and redberry juniper have increased considerably on non-burned sites in recent years. Many of the climax shrubs are present.

The Mixed-brush/Shortgrass/Annuals Community (2.2) is the result of many years of mesquite and/or juniper domination. The trees and shrubs can approach 70 percent ground cover with continued heavy grazing. Common understory shrubs are pricklypear, algerita, sumacs, lotebush, yucca, Texas persimmon, elbowbush, pricklyash, croton and tasajillo. Shortgrasses and low quality annual and perennial forbs occupy the woody plant interspaces.

Submodel

Description

The Converted Land Community has been cultivated for cropland or pastureland purposes. Small grain or forage sorghum may be cropped. Permanent native and introduce pasture may also be planted. Sometimes the community may be abandoned and let “go back” to native species encroached by woody species.

Submodel