Serpentine 25-32 PZ

Description

The Tall/Midgrass Savannah State (1), or reference State, is an open savannah characterized by grassland (dominated by little bluestem and sideoats grama) interspersed with scattered mottes dominated by oak trees. The information from this community comes from experienced field range specialists and from the Serpentine PE31-44 Range Site Description approved April 5, 1973. This community requires relatively frequent fire and/or brush control (every 5 to 10 years) to maintain the savannah appearance. Without fire, shrubs will begin to dominate the open areas eventually resulting in a nearly closed canopy of shrubs and trees.

The community can be maintained through the implementation of fire and brush management, combined with properly managed grazing that provides adequate growing season deferment to allow the establishment of midgrass propagules and/or the recovery of the vigor of stressed plants.

Little bluestem, sideoats grama, meadow dropseed, vine mesquite, and plains lovegrass dominate the herbaceous component of the site. Forbs commonly found on the site include Mexican sagewort, bundle flower, Engelmann’s daisy, western ragweed, orange zexmenia, and sensitive briar. Shrub and tree species found in the Tall/Midgrass Savannah State (1) include species of oaks, whitebrush, pricklypear, and honey mesquite.

Shrubs continually increase in the open areas of the savannah and in the understory of the mottes. This pressure to move towards a woodland or shrubland community if further increased when aggressive, invasive shrubs become a part of the community.

Although large, land-clearing crown fires are relatively rare on this site, similar impacts to the mature hardwoods occur when trees are cleared from the site by dozing, chaining, or spraying. If a manager combines woodland removal with proper grazing management and ongoing, maintenance level brush control, a woodland community could shift to a grassland community, mimicking the natural shift that occurred with large land-clearing fires.

Maintaining the grassland would require diligent brush control. There are examples where intensive targeted grazing with goats has maintained a grassland or savannah community on this site. The grassland and open savannah communities have proven to be difficult to manage. This is due to the difficulty in combining effective brush management with grazing management that provides for grazing events of proper intensity and sufficient periods of deferment.

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Description

The information from this community comes from experienced field range specialists and from the Serpentine PE31-44 Range Site Description approved April 5, 1973. With abusive grazing practices, annual forbs may increase. Short grasses such as hairy grama and curly mesquite also increase. Woody plants such as cedar and algerita increase in pockets of deeper soil. This State can be restored to something close to the Reference State unless there has been a loss of soil and soil function that could not be restored in a management time frame.

Dominant plant species

1. oak (Quercus), tree

2. hairy grama (Bouteloua hirsuta), grass

3. curly-mesquite (Hilaria belangeri), grass

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