Western Wet Loess Terrace - PROVISIONAL

Description

Exemplary examples of the full range of plant communities and ecological processes that were once commonplace on this ecological site no longer exist. Vestiges of this once vast system are primarily relegated to abandoned woodlots and narrow, roadway corridors that now hold the only remaining example of native prairie vegetation that was once part of the greater ecological system. However, there is one example where the soils of this site occur in complex with other ecological sites forming a mosaic of wet hardwood flats (this ecological site), loblolly pine flats, and alkali flatwoods within a relatively confined area. It is from this example and remaining remnants, mostly abandoned woodlots, that we draw a greater understanding of the “perceived” reference conditions for this ecological site.

Klimas et al. (2012) identified this site as “hardwood flats (wet phase).” The saturated, poorly drained soils during winter and spring supports conditions suitable for more lowland species such as willow oak, overcup, and pin oak – the latter two more typical of vernal pools. The drying of the soils by summer create conditions suitable for more upland species, the principal species of which is delta post oak and/or post oak. To the south, loblolly pine is locally a dominant species. However, loblolly pine has a fairly restricted range in the Western Lowlands and is not a characteristic species through the northern portions of this ecological site (T. Foti, personal communication).

Embedded among the woodlands of this site were prairies and savannas, some of which were likely extensive. Vegetation of the open areas would have been quite similar to that of the Grand Prairie to the south. It is generally held that areas of prairie extended or “fingered” northward from the Grand Prairie province well into the Western Lowlands (T. Foti, personal communication).

Two community phases are recognized for representing the reference state of this ecological site: 1) the open structure of the flatwoods and 2) prairie and savanna.

Of the utmost concern, this site has incurred tremendous alteration to drainage. Any attempt to reestablish perceived reference conditions of a stand or a local site must first restore the natural hydrology of that site, which may entail removing drainage structures. If not, management may improve stand structure and even composition to a degree, but the site, overall, will remain in an altered state relative to the reference state. Retaining drainage structures (either pulling excessive water off or retaining water for rice) will directly influence the types of vegetation that colonize the site, which may be entirely different than reference conditions.

Submodel

Description

This state is representative of sites that have been converted to and maintained in pasture and forage cropland, typically a grass – legume mixture. For pastureland, planning or prescribing the intensity, frequency, timing, and duration of grazing can help maintain desirable forage mixtures at sufficient density and vigor (USDA-NRCS, 2010; Green et al., 2006). Overgrazed pastures can lead to soil compaction and numerous bare spots, which may then become focal points of colonization by undesirable plants or weeds. Soils exhibiting the core concepts of this site have a pronounced period of wetness followed by droughty conditions. Limitations may pertain mainly to periods of extreme wetness.

Planning or prescribing the intensity, frequency, timing, and duration of grazing can help maintain desirable forage mixtures at sufficient density and vigor (USDA-NRCS, 2010; Green et al., 2006). Because of the limitations of this site, grazing may be limited to small intervals within the appropriate season(s). It is strongly advised that consultation with State Grazing Land Specialists and District Conservationists at local NRCS Service Centers be sought when assistance is needed in developing management recommendations or prescribed grazing practices on this site.

Submodel

Description

Agriculture production on this site is somewhat limited due to seasonal wetness. However, the vast majority of the acreage in this ecological site is in agriculture production. Where idle woodlots occur today, those sites were very likely cropped at some point in the past.

Submodel

Description

Most, if not all, of the woodlots and local patches of woodlands occurring on this site represent this state. These stands still support some of the components that characterizes the community. The structure of these stands are typically denser than a late development, fire-influenced stand. However, the co-occurrence of upland and lowland taxa and a moderately open understory provide indications of hydroxeric influences. Restoration potential of these sites back to reference conditions is possible, provided that the appropriate management regime is initiated and maintained. Before this can happen, the natural hydrology of the area of interest must first be restored, which may entail removing drainage structures. If not, management may improve stand structure and even composition to a degree, but the site, overall, will remain in an altered state relative to the reference state.

Submodel