Shallow 25-28" PZ

Description

The Midgrass Prairie Community (1.1) is the reference plant community of the Shallow Ecological Site. It is estimated to have been an open prairie, dominated primarily by warm-season midgrasses, such as little bluestem, sideoats grama, and plains bristlegrass, with scattered tallgrasses, such as big bluestem and Indiangrass, as well as a fair component of cool-season plants including Texas wintergrass and sedges. Shortgrasses, such as curlymesquite and buffalograss made up a minor component of the plant community. The plant community also included a wide variety of perennial forbs such as bushsunflower, Engelmann’s daisy, dotted gayfeather, and halfshrub sundrop. The site would have had less than 5% woody canopy, including low shrubs and a few scattered trees. The tallgrasses and woody species usually occurred in the vicinity of limestone outcrops, drainageways, and hillside crests.

The Shortgrass/Shrub-Dominant Community (1.2) was dominated by less palatable species of shortgrasses. Woody species, including honey mesquite, catclaw and lotebush increase in canopy cover and density. Texas wintergrass increased considerably in the shadier understory and became a co-dominant with the shortgrasses, which began to dominate the more open areas.

Submodel

Description

The Mesquite/Pricklypear/Shortgrass Community would be dominated by an overstory of honey mesquite. The increased canopy of woody plants would create a cooler understory, in which Texas wintergrass would increase significantly. Pricklypear, tasajillo, and Texas wintergrass would co-dominate the understory, replacing many of the remaining warm-season midgrasses. Shortgrasses, including curlymesquite, buffalograss, slim tridens, and hairy tridens would greatly increase and become the dominant warm-season grass component of this plant community. Midgrasses, which dominated the reference plant community, will be scarce but remnants will remain due to their resilience and presence in soil seed banks. The tallgrasses would no longer occur in this degraded state. The more palatable forbs would be replaced by less preferred species.

Submodel

Description

The Native Seeding Community is the use of adapted native grass mixtures, such as sideoats grama, plains bristlegrass, and green sprangletop which are commonly used. Forbs and shrubs, such as bush sunflower and fourwing saltbush (Atriplex canescens), respectively, have been used in native mixtures, with limited success. Commercial seed sources of adapted forbs and shrubs generally are scarce. Seeded range provides forage production similar to or sometimes greater than most natural grassland communities of the Shallow Ecological Site. Annual production generally ranges from 2000 to 3000 pounds air-dry biomass per acre. Native grasses can successfully compete with the annual grasses and forbs, which often appear during initial establishment. Native grasses are somewhat slower than some of the introduced pasture grasses in establishing viable stands. However, once established and with proper grazing management, native grasses have greater longevity and sustained productivity without high-level energy inputs.

The Introduced Seeding Community is a management-induced vegetative state. It is the result of intensive cultural practices designed to speed the vegetative transformation of a natural plant community, primarily to produce a more economically desired plant community. Seeded pasture usually consists of a monoculture of grasses, such as kleingrass, old-world bluestem, or weeping lovegrass, or a mixture of two or three compatible species. These are generally introduced or improved cultivars, having characteristics desired for forage, erosion control, water conservation, or wildlife habitat. In most cases seeded pastureland is management-oriented for forage production, but may have secondary benefits. Such plant communities usually provide higher levels of production than degraded natural plant communities on this site. Although this vegetative state may provide productive and seasonally nutritious forage for livestock, it may lack the biodiversity of natural plant communities, more essential to many wildlife species.

The Annual Crop Community is a management-induced state produced through transformation of a natural plant community or another management-induced plant community, through plowing and cultivation. These areas are seeded to cash or forage crops, primarily small grains, forage sorghum, and grain sorghum. Small grains generally include wheat and oats, either for grain or forage, and sometimes both in years of favorable rainfall. Many of these areas have been successfully cultivated for production of small grains, forage sorghums, and grain sorghum. Cool-season crops generally do better than warm-season crops, due to the droughty nature of the site.

Submodel