State 1
Reference State

The reference state is considered to be representative of the native range of variability under pre Euro-settlement conditions. Community phase changes in this state are primarily driven by a fire return interval less than 5 years, periodic drought cycles, and light to moderate grazing pressure. This state was co-dominated by warm and cool season grasses.

Community 1.1
Big Bluestem - Indian Grass - Porcupine Grass

Community 1.2
Lead Plant - Big Bluestem - Indian Grass

Pathway 1.1A
Community 1.1 to 1.2

Lack of fire greater than five years, drought, and heavy grazing.

Pathway 1.2A
Community 1.2 to 1.1

Increased fire return interval, less than 5 years; return to more frequent grazing.

State 2
Invaded State

This state is dominated by cool season invasive grasses resulting from heavy grazing and high ground litter accumulation. Some native species are still present.

Community 2.1
Big Bluestem - Smooth Brome - Kentucky Blue Grass

Community 2.2
Smooth Brome - Kentucky Blue Grass

This community phase is dominated by Kentucky bluegrass , smooth brome, or other introduced cool-season grasses. Big bluestem is severely reduced and is suffering in terms of vigor and reproductive capacity.

Community 2.3
Shruby/Woody Encroached

Invasive shrubs and woody species dominate this site after encroaching on prairie communities.

Pathway 2.1A
Community 2.1 to 2.2

Lack of disturbance, over grazing, buildup of heavy litter layer.

Pathway 2.2A
Community 2.2 to 2.1

Timed grazing and fire

Pathway 2.2B
Community 2.2 to 2.3

Lack of disturbance

Pathway 2.3B
Community 2.3 to 2.1

Intensive prescribed burning

Pathway 2.3A
Community 2.3 to 2.2

Intensive prescribed burning

State 3
Encroached State

The encroached state is characterized by increased cover of native woody species due to the absence of wildfire. Ecological processes such as energy distribution, nutrient cycling, and soil moisture recharge are being controlled by trees. Herbaceous species in the understory experience reduced productivity and reproductive capacity due to shading.

Community 3.1
Green Ash - Bur Oak - Quaking Aspen

State 4
Agricultural state

Indefinite use for agriculture including tillage and crop production.

Community 4.1
Rowcrop

Planted row crops such as corn and soybean.

Community 4.2
Seeded Grassland

This community phase is characterized by the seeding of or reestablishment of long-lived, perennial grasses both native and non-native following previous cultivation or tillage. Functional groups and visual aspect of the vegetation may be similar to the reference state, however ecological function is different. Tillage and cultivation negatively impacts soil structure and organic matter leading to lower rates of infiltration and increased runoff.

Pathway 4.1A
Community 4.1 to 4.2

Seeded grass species sowed.

Pathway 4.2A
Community 4.2 to 4.1

Tillage and seasonal row crop planting.

Transition T1A
State 1 to 2

Triggers: the introduction of non-native, cool-season, perennial grasses that can not be removed from the system. Slow variables: prolong periods of heavy grazing pressure reduce vigor and reproductive capacity of native species allowing non-natives to establish. This process can be exacerbated by the absence of wildfire that allows for the accumulation of litter that favors non-native, cool-season, grasses.

Transition T1B
State 1 to 3

Slow variables: Lengthened fire return intervals (greater than 5 years) allow native woody species in encroach and being to dominant the ecological processes. As canopy cover increases herbaceous perennial understory is reduced in both vigor and reproductive capacity. Heavy grazing pressure may exacerbate the impacts of woody species encroachment Thresholds: Nutrient cycling, energy capture and hydrologic function have been spatially and temporally truncated by the dominance of trees.

Transition T1C
State 1 to 4

Triggers: Lands have been cleared and cultivated. These management actions represent a discrete event that truncates energy, nutrient, water cycling dynamics reducing ecological resilience. Thresholds: Once the site is cultivated, soil properties such as structure and organic matter are permanently altered.

Transition T2A
State 2 to 3

Slow variables: Lengthened fire return intervals (greater than 5 years) allow native woody species in encroach and being to dominant the ecological processes. As canopy cover increases herbaceous perennial understory is reduced in both vigor and reproductive capacity. Heavy grazing pressure may exacerbate the impacts of woody species encroachment Thresholds: Nutrient cycling, energy capture and hydrologic function have been spatially and temporally truncated by the dominance of trees.

Transition T2B
State 2 to 4

Triggers: Lands have been cleared and cultivated. These management actions represent a discrete event that truncates energy, nutrient, water cycling dynamics reducing ecological resilience. Thresholds: Once the site is cultivated, soil properties such as structure and organic matter are permanently altered.

Restoration pathway R3A
State 3 to 1

The encroached state will not return to the reference state without significant management actions. To restore this community to reference-like conditions requires the continued use of prescribed burning (fire return interval of ~5years is required to maintain the reference state). Management may also initially require herbicide and mechanical brush control. Additional considerations include deferment from grazing and the health and vigor of remnant native grass species in the understory.

Context dependence. Fire return interval less than 5 years, plus herbicide or thinning of shrubs.

Restoration pathway R3B
State 3 to 2

Triggers: Widespread fire, or multiple fires, severe enough to kill overstory of woody species Slow variables: prolonged heavy grazing, may also be coupled with drought and the introduction of non-native species. Thresholds: hydrologic cycling, nutrient cycling, energy capture are controlled by herbaceous species

Transition T3A
State 3 to 4

Triggers: Lands have been cleared and cultivated. These management actions represent a discrete event that truncates energy, nutrient, water cycling dynamics reducing ecological resilience. Thresholds: Once the site is cultivated, soil properties such as structure and organic matter are permanently altered.