Northern Wet Alluvial Flat - PROVISIONAL
Scenario model
Current ecosystem state
Select a state
Management practices/drivers
Select a transition or restoration pathway
- Transition T1A More details
- Transition T1B More details
- Transition T1C More details
- Transition T1D More details
- Restoration pathway R2A More details
- Transition T2A More details
- Transition T2B More details
- Transition T2C More details
- Restoration pathway R3A More details
- Restoration pathway R3B More details
- Transition T3A More details
- Transition T3B More details
- Restoration pathway R4A More details
- Restoration pathway R4B More details
- Transition T4A More details
- Restoration pathway R5A More details
- Restoration pathway R5B More details
- Restoration pathway R5C More details
-
No transition or restoration pathway between the selected states has been described
Target ecosystem state
Select a state
Description
This ecological site is associated with one of the most charismatic, but yet, impacted and altered, ecological systems in the MLRA, the low-gradient riverine systems of the Loess Plains. The majority of the low-gradient streams in the ecoregion have been greatly modified by channelization and levee construction. Therefore, a very narrow suite of reference sites are available for observation and study. This state is considered representative of the wet alluvial flats within unmodified stream and river floodplains.
Vegetation associated with this site exhibits signs of hydric conditions and the dominant components of the system are generally wetland obligates and facultative wetland species. The vegetation that characterized the drier flats and higher landforms within floodplain system have mostly dropped out and are replaced by species more tolerant of anoxic conditions.
Submodel
Description
This state is characterized by the regeneration or regrowth of a pre-existing forest stand following a major, stand-replacing disturbance. Scale of the disturbance is at the stand level and is greater than one acre in size (Johnson et al., 2009). Potential types of disturbances include catastrophic windstorms, silvicultural clearcuts, particularly destructive ice storms, and long-term inundation from altered hydrology (e.g., beaver). For impacts other than permanent inundation, the resulting even-aged stand (or single-cohort) is set on a new course of development, which is highly dependent upon several critical factors including: the composition and structure of the stand prior to the disturbance; the degree or intensity of the disturbance; size and configuration of the disturbed area; and distance to seed sources (Oliver and Larson, 1990).
If the site has become flooded and inundated throughout the growing season (altered hydroperiod), a new series of successional stages and ecological processes may occur that transition this site to a stage more similar to an early successional backswamp site. Under the new hydroperiod, soils are ponded throughout much or all of the year and the corresponding vegetation community becomes more characteristic of a marsh and eventually, a young swamp. If deposition is exceedingly slow in the newly inundated environment, flooded/ponded conditions may prevail over a long period of time, eventually leading to dominance by components of the Backswamp ecological site, which is generally a bald cypress – water tupelo association. However, if deposition rates are fast, eventually the dominant components of this site may return following a series of successional transitions (e.g., from open water to herbaceous – scrub-shrub to young forested wetland). The length of time for this transition to take place ultimately depends on deposition rates, composition of the site through each successional stage, and eventual colonization by the species associated with this site (Hodges, 1997). Depending on the type and severity of the disturbance, many years may be required before a return to reference conditions occurs on this floodplain site.
Submodel
Description
This state represents the breadth of forest management activities on this site. Various management or silvicultural methods can lead to very different structural and compositional results within a managed stand. The range of methods are diverse and include even-aged (e.g., clearcut and shelterwood) and uneven-aged (single tree, diameter-limit, basal area, group selection, etc.) approaches. Included within these methods is an option to reduce competition and achieve maximum growth potential of the desired species. Inherently, these approaches result in different community or “management phases” and possibly alternate states, depending on local floodplain dynamics. The decision to represent these varying management strategies 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 and description iterations of this site will provide more detail on this state and associated management phases.
A limitation of this site is periodic to frequent flooding over long to very long durations. Management activities may need to be adjusted to drier times of the year.
Submodel
Description
This state is representative of sites that have been converted to and maintained in pasture. This state is generally restricted to areas that occasionally flood for brief to long periods and along protected areas (i.e., channelized and leveed). Planning or prescribing the intensity, frequency, timing, and duration of grazing will be very important on this wet site. Wetness is a limitation for this management option. Overgrazing on this site can lead to soil compaction, numerous bare spots, and deep muck and muddy conditions that effectively reduces or destroys plant establishment and productivity.
Establishing an effective pasture management program can help minimize degradation of the site and assist in maintaining growth of desired forage. An effective pasture management program includes: selecting well-adapted grass and/or legume species that will grow and establish rapidly; maintaining proper soil pH and fertility levels; using controlled grazing practices; mowing at proper timing and stage of maturity; allowing new seedings to become well established before use; and renovating pastures when needed (Rhodes et al., 2005; Green et al., 2006). 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. Of note, the flooding and wetness limitations on this site will severely limit the type of forage suited for this site. An alternative land use and management strategy of this site warrants consideration.
Submodel
Description
This site has severe flooding and wetness limitations for cropland production. The state is provisionally included here mainly due to its occurrence within small, occasionally flooded areas and within protected floodplains. Planting is often delayed which limits the types of crops that can be established.
Submodel
Mechanism
This pathway represents a large-scale, stand replacing disturbance, which may be caused by a catastrophic windstorm (e.g., straight-line winds, tornado), ice storm, severe fire, or a silvicultural clearcut. For this stressor to occur, most or all of the overstory must be removed or destroyed. A few residual trees may persist, but overall, the disturbance must be intensive enough, at least one acre or larger (Johnson et al., 2009), that a new, even-aged stand is created.
Mechanism
This pathway consists of prescribed silvicultural activities specifically designed to meet stand compositional and production objectives. Activities may include release cuttings through a combination of low and high thinning, mechanical and chemical control of competition, and artificial regeneration (i.e., planting) of sites with low oak presence. A variety of silvicultural methods may be employed including group selection, single tree selection harvests (all classes/condition; avoid “high-grading”), or even-age management (clearcut).
Mechanism
Actions required to convert forests to grassland or forage production include forest clearing, stump removal, herbicide application, seedbed preparation, and the establishment of desired plants. Caution: there are severe flooding and wetness limitations to this site and pastureland, as a land use, is generally considered to be poorly suited. (This pathway is generally relegated to smaller stream systems and/or protected floodplains.)
Mechanism
Actions include mechanical removal of vegetation and stumps; herbicide treatment of residual plants; and preparation for planting. Warning: there are severe flooding and wetness limitations to this site and cropland, as a land use, is considered unsuited (USDA-NRCS, 1997). (This pathway is generally relegated to smaller stream systems and/or protected floodplains.)
Mechanism
This pathway represents a return to reference conditions through natural succession, if the disturbance occurred within a reference community. Depending upon objectives and stand condition, management activities to aide recovery may include exotic species control and silvicultural treatment that benefits oak regeneration and establishment (e.g., TSI practices such as crop tree release, low thinning, and cull removal). This pathway will occur only under the natural hydrologic regime (i.e., naturally meandering channel with NO levees). It should be noted that a return to reference conditions requires that the natural hydrodynamics must be restored to the system. (Of note, exceptional conservation measures may be implemented in hydrologically altered systems, but the natural ecological processes and functions between the stream and its associated floodplain remains disconnected and all resulting actions remain in an altered state.)
Mechanism
This pathway represents the development of an even-aged stand that is prescribed to meet compositional and production objectives. However, severe flooding and seasonal wetness may dictate management actions.
Mechanism
Actions required to convert forests to pasture or forage production include forest clearing, stump removal, herbicide application, seedbed preparation, and the establishment of desired plants. However, periodic flooding and seasonal wetness may dictate management actions. (This pathway is generally relegated to smaller stream systems and/or protected floodplains.)
Mechanism
Actions include mechanical removal of vegetation and stumps, herbicide treatment of residual plants, and preparation for planting. Caution: this site is generally poorly suited or unsuited for agriculture production. (This pathway is generally relegated to smaller stream systems and/or protected floodplains.)
Mechanism
Natural succession over a period of time may transition a former timber-managed stand to one supporting reference conditions. Some question remains whether a return to reference conditions will occur in every situation, especially since some components may have been selectively culled from the stand. Management activities to aide recovery may include exotic species control and silvicultural treatment. Floodplains where streams have been channelized and leveed must have the natural hydrology restored BEFORE reference conditions are achieved.
Mechanism
This pathway represents a large-scale, stand-initiating disturbance, which effectively removes most or all of the pre-existing overstory. Disturbances may include a catastrophic windstorm, silvicultural management (even-aged), and long-term flooding or inundation (e.g., beaver-influences).
Mechanism
Actions required to convert forests to pasture or forage production include forest clearing, stump removal, herbicide application, seedbed preparation, and the establishment of desired plants. However, periodic flooding and seasonal wetness may dictate management actions. (This pathway is generally relegated to smaller stream systems and/or protected floodplains.)
Mechanism
Actions include mechanical removal of vegetation and stumps, herbicide treatment of residual plants, and preparation for planting. Caution: this site is generally poorly suited or unsuited for agriculture production. (This pathway is generally relegated to smaller stream systems and/or protected floodplains.)
Mechanism
This pathway represents natural succession back to perceived reference conditions. The period required for this transition to take place likely varies by location and is dependent upon local site conditions. Many years may be required before a return to the late development reference community occurs and the rate or time period of return is directly dependent on many variables. Significant efforts may be required before a return to reference conditions is achieved (e.g., exotic species control, appropriate connectivity between stream and floodplain, potential artificial regeneration of community components, etc.). Floodplains where streams have been channelized and leveed must have the natural hydrology restored BEFORE reference conditions are achieved.
Mechanism
This pathway represents prescribed management strategies for transitioning abandoned pastureland to managed woodland. Activities may include artificial regeneration of and management for desired species and exotic species control.
Mechanism
Actions include mechanical removal of vegetation and stumps; herbicide treatment of residual plants; and preparation for planting. Caution: this site is generally poorly suited or unsuited for agriculture production. (This pathway is generally relegated to smaller stream systems and/or protected floodplains.)
Mechanism
This pathway represents natural succession back to perceived reference conditions. The period required for this transition to take place likely varies by location and is dependent upon local site conditions. Many years may be required before a return to the late development reference community occurs and the rate or time period of return is directly dependent on many variables. Significant efforts may be required before a return to reference conditions is achieved (e.g., exotic species control, appropriate connectivity between stream and floodplain, potential artificial regeneration of community components, etc.). Floodplains where streams have been channelized and leveed must have the natural hydrology restored BEFORE reference conditions are achieved.
Mechanism
This pathway represents prescribed management strategies for transitioning abandoned cropland to managed woodland. Activities may include artificial regeneration of and management for desired species and exotic species control. Depending on location and watershed size, floodplains supporting this site may be subjected to frequently flooding for very long durations. In general, timberland management on this site has some seasonal and wetness limitations.
Model keys
Briefcase
Add ecological sites and Major Land Resource Areas to your briefcase by clicking on the briefcase (
) icon wherever it occurs. Drag and drop items to reorder. Cookies are used to store briefcase items between browsing sessions. Because of this, the number of items that can be added to your briefcase is limited, and briefcase items added on one device and browser cannot be accessed from another device or browser. Users who do not wish to place cookies on their devices should not use the briefcase tool. Briefcase cookies serve no other purpose than described here and are deleted whenever browsing history is cleared.
Ecological sites
Major Land Resource Areas
The Ecosystem Dynamics Interpretive Tool is an information system framework developed by the USDA-ARS Jornada Experimental Range, USDA Natural Resources Conservation Service, and New Mexico State University.