Wet Bottomland 19-26" PZ

Description

The Tall/Midgrass Community was dominated by tall and midgrasses species when European settlers first arrived. The presence of a high water table and infrequent flooding greatly influenced the plant community. Woody plants, primarily cottonwood, hackberry, willow, and American elm were widely scattered along the stream course and draws. Shrubs and vines such as bumelia, plum, indigobush and grape were present but kept suppressed by periodic fires and grass competition. The herbaceous component accounted for 85 to 95 percent of the site’s primary annual production, with tallgrasses accounting for 40 to 50 percent of the herbage production. Alkali sacaton and inland saltgrass occurred in small amounts where saline conditions developed. Canada wildrye and western wheatgrass were common cool-season grasses. Common forbs included Maximilian sunflower, Illinois bundleflower, prairie clover and Engelmanndaisy. Annual total production ranges from 5,000 to 9,000 pounds per acre.

The Midgrass/Tallgrass Community (1.2) is now being encroached by indigenous or invading woody species that had been held at low densities by repeated fires and competition from a vigorous grass component. Numerous woody species, including willow, hackberry, and cottonwood, are increasing in density. The woody canopy varies between 10 and 25 percent depending on severity of grazing, time since last burn, and availability of invading species. Brushy species, such as bumelia, indigobush, plum, and willow baccharis may also increase. The preferred tallgrasses are being replaced by the more grazing resistant midgrasses. Characteristic grasses are little bluestem, sideoats grama, tall and meadow dropseed, vine mesquite and alkali sacaton. Sedges and rushes are characteristic species where the water table remains near the surface. Most of the perennial forbs found in the historic climax remain in this plant community. In this community, the increasing woody species are generally less than five feet tall. Annual total production ranges from 4,500 to 8,000 pounds per acre.

Dominant plant species

1. black willow (Salix nigra), tree

2. switchgrass (Panicum virgatum), grass

Submodel

Description

The Midgrass/Shrubs Community (2.1) presents a 25 percent or greater woody plant canopy dominated by cottonwood, hackberry and willows. Plum, western soapberry, baccharis and indigobush, are also increasing in density and size. There is a decline in the diversity of the grassland component and an increase in woody species and annual forbs. In the more saline areas inland saltgrass and alkali sacaton may dominate. Remnants of reference community grasses and forbs and unpalatable invaders occupy the interspaces between trees and shrubs. Cool-season grasses, such as Canada wildrye, Texas bluegrass and western wheatgrass, can be found under and around woody plants.

The Woody Bottomland Community (2.2) is dominated by several woody species including willows, baccharis, and hackberry. Western soapberry, salt cedar, and Chinese elm have increased tremendously in the past few decades. They often form dense woodlands on the site where grazing has been heavy and continuous and fires have been excluded. Salt cedar, along with baccharis, is particularly problematic where salinity has increased. Common understory shrubs are buttonbush, indigobush, and plum. Shortgrasses, cool-season grasses and low quality annual and perennial forbs occupy the tree interspaces. The brush canopy increases in density while shortgrasses, such as threeawns, red grama, and sedges replace the more palatable mid and shortgrasses.

Dominant plant species

1. cottonwood (Populus), tree

2. hackberry (Celtis), shrub

3. willow (Salix), shrub

4. threeawn (Aristida), grass

Submodel