Northern Wet Loess Interfluve

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 that have undergone numerous impacts since settlement. Still, there appears to be a close correlation between the species reported in earlier state reports (e.g., Loughridge, 1888; Lowe, 1921) and more recent accounts of extant woodlots (Bryant, 1999). One major difference between the historic community and existing woodlands is the absence of fire, which is thought to have been an important disturbance factor (NatureServe, 2009). The one landform in which very little to no information has been found is the upland, seasonally ponded depressions of this site. We have information regarding these systems on terraces (see Northern Ponded Loess Terrace ecological site) but no information has been found regarding these loessal, vernal pools in the literature or from other investigators. They appear to have been largely overlooked.

Reference conditions of this site are essentially based on rapid assessments and community projections. Classifying this system with a single plant association name is extremely difficult, if not impossible, due to the variability of species occurring on each of the different landforms associated with the site. Nonetheless, the flatwoods community phase has been selected to represent the range of species occurring on this site due to its aerial extent. Species considered important or restricted to a specific landform will be specifically addressed (e.g., upland depressions).

As additional information becomes available, revisions to this site may warrant significant changes. At a minimum, a new site will be developed for areas to the south in Mississippi where loblolly and shortleaf pine enters the community as components.

Of concern, portions of this site have been altered to facilitate rapid drainage (e.g., depressions and headslopes). Any attempt to reestablish perceived reference conditions of a stand or a local site must first restore the natural hydrology of that location, 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 perceived reference conditions, which includes a seasonal high water table. Retaining drainage structures will directly influence the types of vegetation that colonize the site, which may be entirely different from the natural vegetation associated with these poorly drained soils.

Submodel

Description

Agriculture production is the dominant land use activity on this site, today, although production is somewhat limited due to seasonal wetness. Many areas in production have some form of drainage structures established due to seasonal saturation of the soil surface.

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

This state represents a broad range of management objectives, options, and stand conditions including woodlots allowed to grow or revert naturally; repeated single-tree harvests (often high-graded); carefully prescribed treatments; and conversion to a monoculture or single-species stand.

Various management or silvicultural methods can lead to very different structural and compositional results. For prescribed management options, methods are diverse, which include even-aged (e.g., clearcut and shelterwood) and uneven-aged (single tree, diameter-limit, basal area, group selection, etc.) approaches. Included within these approaches is an option to use disturbance mechanisms (e.g., fire, TSI, etc.) to reduce competition and achieve maximum growth potential of the desired species. Inherently, these various approaches result in different community or “management phases” and possibly alternate states. The decision to represent these varying approaches and management results into a single state and phase at this time hinges on the need for additional information in order to formulate definitive pathways, management actions, and community responses. Forthcoming inventories of this site will provide more detail on this state and associated management phases.

Of warning, there are significant timber management limitations due to alternating seasonal wetness and dryness; the latter often rendering the soil very hard and compact. These collective impacts could lead to high seedling mortality and/or low productivity of individual trees. Implementing this state or management option on this site should be carefully reviewed and considered.

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Description

This alternative state is included to represent the range or breadth of conservation actions that may be implemented and established should other land uses be discontinued within a given location. Several actions may be chosen including the standard of establishing: native warm season grasses; suitable forbs for pollinators; select native trees to manage for forest or woodland conditions. If at all possible, the herbaceous species established should be derived from the “wild types” (genetic stock) from the Loess Plains or from adjoining ecoregions. This action would help preserve the unique genetic material from the area and would help to reintroduce the native herbaceous taxa back into a portion of their former range.

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