State 1
Grassland

This is the reference or diagnostic community for the site. The description is based on early range site descriptions, clipping data, professional consensus of experienced range specialists, and analysis of field work

Community 1.1
Tallgrass

Figure 12. Loamy Bottomland #1, HPC

Figure 13. Loamy Bottomland, Talgrass Dominant

The reference community is dominated by a composite of tall, warm season grasses. Big bluestem, eastern gamagrass, Indiangrass, prairie cordgrass and switchgrass comprise approximately 80 percent of the vegetation. Secondary grasses occur in minor amounts. These secondary grasses include tall dropseed, Florida paspalum, beaked panicum, little bluestem and knotroot bristlegrass. Cool season grasses and grasslike plants such as Canada wildrye, Virginia wildrye and sedges may contribute up to five percent of the total vegetation on site. Most of the major grasses grow during the months April through June. In a typical year, approximately 75 to 80 percent of the annual herbage production is completed by the first of July. Both eastern gamagrass and prairie cordgrass have been observed emerging through several inches of sediment deposited on the site by flood waters.

Numerous forbs prevail on this site. The more abundant forbs are wholeleaf rosinweed, Maximilian sunflower, sawtooth sunflower and Illinois bundleflower. Other common forbs are cupleaf rosinweed, stiffleaf sunflower, ashy sunflower, Canada goldenrod, heathaster, smooth oxeye, prairie acacia and roundhead lespedeza. Under moderate levels of grazing, the major HPC grasses on this site will remain very durable and plant composition proportions can be maintained almost indefinitely. Most of the palatable forbs will decrease with light to moderate continuous grazing, however, it is possible to maintain these palatable forbs under periodic deferment by using prescribed grazing.

Overgrazing by livestock will eventually have major impacts on vegetation composition. A decrease in vigor of the more palatable grasses will encourage a gradual increase in secondary plants such as tall dropseed, purpletop, silver bluestem and sideoats grama. Many of the forbs are very palatable and readily selected by livestock. Forbs that increase with overgrazing include heathaster, tall goldenrod, Missouri goldenrod, western ragweed and Louisiana sagewort. Woody plants such as buckbrush, blackberry, roughleaf dogwood, smooth sumac, persimmon, hawthorn, elm, oak and ash also increase under Long term overgrazing, especially if there is also absence of fire. Often, the total elimination of fire on this site, regardless of grazing intensity implemented, can result in the transformation of a herbaceous dominated plant community to a community almost closed by tree canopy. Major tree species that encroach on the site are oak, ash, elm, hackberry, pecan, sycamore and cottonwood.

Community 1.2
Midgrass/Tallgrass

This plant community is dominated by a mixture of midgrasses and tallgrasses with the midgrasses more prevelant than the tallgrasses. There has been a decrease in the more palatable grasses such as eastern gamagrass, big bluestem and Indiangrass. These grasses have been replaced by an increase in secondary grasses including purpletop, knotroot bristlegrass, and tall dropseed. Western wheatgrass is more abundant in northern counties. Shortgrasses such as buffalograss and fall witchgrass are found in some areas. These changes have resulted in a reduction in herbage production on the site.

The dominant perennial forbs are heathaster, Canada goldenrod, Baldwin ironweed and tall eupatorium. Heavy stands of annuals often occur after periods of close grazing. These annuals include seacoast sumpweed, common sunflower, giant ragweed, annual ragweed and marestail.

Continuous overgrazing has reduced the fuel load and lessened the occurrence and subsequent benefits of prescribed burning. Shrubs, including buckbrush, blackberry, sumac and roughleaf dogwood are common. Tree species such as elm, hackberry, Osage orange and eastern redcedar are often scattered across the site.

Prescribed burning coupled with prescribed grazing, involving deferment during all or a part of the growing season, will increase the desirable grasses. This site can be restored to near reference conditions in eight to twelve years.

Pathway 1.1A
Community 1.1 to 1.2

If the site is subjected to abusive grazing for multiple growing seasons and the more palatable tallgrass species are not allowed adequate recovery, the plant community will begin to transition to a Midgrass dominated plant community(1.2). This community shift may also occur as a result of long term drought as the Midgrass and Shortgrass species are better adapted to dry climates. This pathway is not a one-way street and it is important to remember that this community shift occurred often, historically, and represents the variability within this Reference Sate.

Pathway 1.2A
Community 1.2 to 1.1

With adequate rest from grazing pressure and favorable growing conditions, this plant community may be able to return to the reference plant community (1.1).

State 2
Woody

The description for this plant community is derived from analysis of limited field data and professional consensus of range trained individuals.
This plant community is a result of the absence of fire. Fire was an important element in suppressing woody plants during the ecological evolution of this site. So, when fire was suppressed for many years, the vegetative composition naturally and gradually shifted towards woody plant dominance. Areas protected from both fire and grazing for 20 to 30 years, or longer, have transitioned from open grassland to closed canopy woodland. Some areas, due to their juxtaposition to streams, were historically protected from reoccurring fires.

Species composition of woody plants will vary from area to area. But generally, tree species will be bur oak, hackberry, elm, ash, sycamore or pecan. Eastern redcedar is becoming more prominent in this plant community. Shrubs and vines common to the site are buckbrush, sumac, blackberry, poison ivy, grape and greenbrier. Combined trees and shrubs may form an overstory canopy of 70 to 80 percent. The understory is dominated by shade tolerant plants such as Virginia wildrye, Canada wildrye, sedges, Scribner’s panicum, Indian woodoats, sweet woodreed and various muhlys.

Herbage production suitable for livestock use is limited. The site provides shelter for both livestock, deer and numerous small mammals. Many species of birds frequent this site.

State 3
Converted

Many loamy bottomland sites have been cultivated over the past century in order to produce crops. Due to the level, deep loam soils, these sites are well suited for Ag production. Within this state, most woody species have been cleared in order to facilitate the access of farm machinery.

Transition T1A
State 1 to 2

Without fire in the ecosystem, woody species may grow and reproduce unchecked. These species may be endemic (pecan, hackberry, etc.) or species introduced to the site by animals (eastern redcedar) or plantings (black locust/honey locust). These woody species have the ability to grow deep roots and locate resources within the soil that herbaceous species may not have access to. This gives them a competitive edge for resources and allows them to expand across the landscape. As this woody encroachment occurs, the site may transition to state 2 where the woody species begin to dominate the ecological functions of the plant community.

Transition T1B
State 1 to 3

Many of these sites have been plowed for farming purposes over the last century. Once the site is cultivated, it transitions to an alternative state (3). The soils structure, organic matter, and biota have been altered and will no longer function the same as the soils in the reference state.

Restoration pathway R2A
State 2 to 1

A carefully planned program will restore the Woody state to a close resemblance to a grassland state. Because the woody community may be difficult to burn (but susceptible to wildfires), some brush management intervention will be needed. Brush management either mechanical, chemical or an integration of both, will allow sunlight energy and soil moisture to be used by tall grasses rather than invasive brush. Careful grazing management will be required for this plant community to be restored to the grassland state (1).

Transition T2A
State 2 to 3

Many of these sites have been plowed for farming purposes over the last century. Once the site is cultivated, it transitions to an alternative state (3). The soils structure, organic matter, and biota have been altered and will no longer function the same as the soils in the reference or woody state.

Restoration pathway R3A
State 3 to 1

Through carefully planned implementation of range seeding, prescribed grazing and rest, the cultivated state can be returned to a plant community similar to those in the reference state.

Context dependence.As a result of cultivation and soil erosion, soil properties are altered and ecological processes are changed. While permanent native vegetation can be re-established to a species mix similar to the reference state, often the site may never be restored ecologically to reference condition. This is especially true of sites that have experience a significant loss of the soil surface horizon. However, many sites have been restored to something very close the reference state and this should always be the target if full ecological restoration is the goal.