Rangeland Health Assessment

• Rangelands are lands where native vegetation, such as grasses, forbs, and shrubs, grows and is managed by a natural ecosystem.
• Rangeland Health (RH) serves as a tool to communicate the condition of rangelands.
• Rangeland health refers to the degree to which the integrity of the soil and ecological processes of rangeland ecosystems are sustained.

Three Primary Attributes of Rangeland Health

• Soil and site stability
• Hydrologic function
• Integrity of the biotic community

Indicators Used to Monitor Rangeland Health

• Rills
• Water flow patterns
• Pedestals and terracettes
• Bare ground
• Gullies
• Litter movement
• Soil surface loss
• Plant community composition and distribution relative to runoff and infiltration
• Compaction layer
• Plant community composition and structure
• Functional/structural groups
• Plant mortality/decadence
• Litter amount
• Annual production
• Invasive plants
• Reproductive capacity of perennial plants
• Optional indicators

Strengths and Limitations with Rangeland Health

• Rangeland health assessments help identify problems, facilitate communication, and evaluate the soil.

Ecological Site Description (ESD)

• Ecological Site Descriptions are a type of soil mapping that classify and describe rangelands.
• ESDs are created by sampling soil and vegetation in specific areas, with the resulting description made accessible online.
• ESDs provide insights into past conditions and aid in creating future management plans.

Uses and Users of Ecological Site Descriptions

• ESDs are used by the NRCS, landowners, and managers.
• Limitations include the impossibility of sampling every inch of land, slow update speeds, and incomplete coverage of all areas.

State and Transition Theory and Models

• State and transition models illustrate how landscapes or ecosystems change over time.

Definitions

• A state represents a distinct vegetation type based on the characteristics of an area, including soil, climate, history, and disturbances.
• A transition is the change from one state to another, occurring through natural processes or management practices, signifying a shift in plant composition potentially caused by disturbances.
• A threshold is a transition boundary that is difficult and expensive to reverse once crossed.
• A phase or community pathway is a change between community phases within a state.

Ecological Succession Theory

• Pioneer species, such as grasses and perennials, are the first to colonize an area.
• Intermediate species, including shrubs and shade-intolerant trees, follow.
• The climax community, featuring shade-tolerant trees, represents the final stage.
• Disturbances like fire can revert a climax community backward.
• Climax communities can be quite stable.

Ecological Resilience

• Ecological resilience is the capacity of an ecosystem to tolerate disturbance without shifting to an entirely different state.
• It measures the amount of change or disturbance required to transform a system and how quickly it stabilizes after a disturbance.

Resilience vs. Resistance

• Resilience describes how well and quickly an ecosystem recovers and stabilizes after a disturbance.
• Resistance refers to the ability of ecological processes to continue functioning unchanged despite a disturbance, limiting the population growth of invading species.