Rangeland health reference sheet

Interpreting Indicators of Rangeland Health is a qualitative assessment protocol used to determine ecosystem condition based on benchmark characteristics described in the Reference Sheet. A suite of 17 (or more) indicators are typically considered in an assessment. The ecological site(s) representative of an assessment location must be known prior to applying the protocol and must be verified based on soils and climate. Current plant community cannot be used to identify the ecological site.

Indicators

1. Number and extent of rills:

   None to very few rills present. Some very minor rill development may occur on steeper slopes or on areas located below exposed bedrock or other water shedding areas where increased runoff may occur. Any rills present should be <1 inch deep, fairly short (<6 feet long) and somewhat widely spaced (4-8 feet). Minor rill development may be observed following major thunderstorm or spring runoff events but should heal during the next growing season.

2. Presence of water flow patterns:

   Some very minor evidence of water flow patterns may be found around perennial plant bases. They show little evidence of current erosion. They are expected to be short (1-3 feet), stable, sinuous and not connected. There may be very minor evidence of deposition. Evidence of water flow may increase somewhat with slope.

3. Number and height of erosional pedestals or terracettes:

   Perennial vegetation shows little evidence of erosional pedestalling (2 to 3% of individual plants). Plant roots are covered and litter remains in place around plant crowns. Terracettes should be absent or, if present, stable. A slight increase in both pedestal and terracette development may occur with increasing slope.

4. Bare ground from Ecological Site Description or other studies (rock, litter, lichen, moss, plant canopy are not bare ground):

   10-15% bare ground on slopes 5 to 25% and 15 to 30% bare ground on slopes greater than 25%. Bare ground spaces should not be greater than 1 to 2 feet in diameter.

5. Number of gullies and erosion associated with gullies:

   None to very few gullies present on site. Rare gullies may be present in landscape settings where they transport runoff from areas of greater water flow such as exposed bedrock. These gullies will be limited to slopes exceeding 20% slope and adjacent to sites where this runoff accumulation occurs. Any gullies present should show little sign of accelerated erosion and should be stabilized with perennial vegetation.

6. Extent of wind scoured, blowouts and/or depositional areas:

   None. No evidence of wind generated soil movement is present. Wind caused blowouts and deposition are not present.

7. Amount of litter movement (describe size and distance expected to travel):

   Most litter resides in place with some redistribution caused by water movement. Minor litter removal may occur in flow channels with deposition occurring within 1 to 2 feet at points of obstruction. The majority of litter accumulates at the base of plants. Some grass leaves and small twigs (grass stems) may accumulate in soil depressions adjacent to plants. Woody stems are not likely to move. However, some litter movement is expected (up to 6 feet) with increases in slopes >15% and/or increased runoff resulting from heavy thunderstorms.

8. Soil surface (top few mm) resistance to erosion (stability values are averages - most sites will show a range of values):

   This site should have a soil stability rating of 4 or 5 under the plant canopies, and a rating of 3 to 5 in the interspaces. The average rating should be a 4. Soil surface textures are loams, fine sandy loams and silt loams.

9. Soil surface structure and SOM content (include type of structure and A-horizon color and thickness):

   Soil surface 0-3 inches. Texture is a loam; color is dark brown (10YR3/3); and structure is weak thin platy. Ochric epipedon ranges to 12 inches. Other soil series may have mollic epipedons. Use the specific information for the soil you are assessing found in the published soil survey to supplement this description.

10. Effect of community phase composition (relative proportion of different functional groups) and spatial distribution on infiltration and runoff:

    Perennial vegetation produces sufficient cover and spatial arrangement to intercept most raindrops and reduce raindrop splash erosion. Litter on soil surface and cryptogamic crusting, where present, also protects soil from splash erosion and encourages a higher rate of infiltration. Plant spatial distribution should slow runoff, allowing additional time for infiltration. Bare spaces are expected to be small and irregular in shape and are usually not connected. Vegetative structure is usually adequate to capture snow and ensure that snowmelt occurs in a controlled manner, allowing maximum time for infiltration, and reducing runoff and erosion in all but the most extreme storm events. When perennial grasses and shrubs decrease due to natural events including drought, insect damage, etc., which reduce ground cover and increasing bare ground, runoff is expected to increase and any associated infiltration reduced.

11. Presence and thickness of compaction layer (usually none; describe soil profile features which may be mistaken for compaction on this site):

    None. Some soils have a calcic horizon that could be mistaken for a compaction layer.

12. Functional/Structural Groups (list in order of descending dominance by above-ground annual-production or live foliar cover using symbols: >>, >, = to indicate much greater than, greater than, and equal to):

    Dominant:

    Perennial bunchgrasses (bluebunch wheatgrass, Thurber needlegrass) > Non-sprouting shrubs (Wyoming big sagebrush).

    Sub-dominant:

    Rhizomatous grasses > Sprouting shrubs > Perennial forbs.

    Other:

    A wide variety of other perennial grasses and both perennial and annual forbs can be expected to occur in the plant community.

    Additional:

    Natural disturbance regimes include fire, drought, and insects. Assumed fire cycle of 35 to 80 years. Functional/structural groups may appropriately contain non-native species if their ecological function is the same as the native species in the reference state (e.g. Crested wheatgrass, intermediate wheatgrass, Siberian Wheatgrass etc.)
    Following a disturbance such as fire, drought, rodents or insects that remove woody vegetation, forbs and perennial grasses (herbaceous species) may dominate the community for a period of time. If a disturbance has not occurred for an extended period of time, woody species will continue to increase. These conditions would reflect a functional community phase within the reference state.

13. Amount of plant mortality and decadence (include which functional groups are expected to show mortality or decadence):

    All age classes of perennial grasses should be present under average to above average growing conditions with age class expression likely subdued during periods of extended drought. Slight decadence in the principle shrubs could occur near the end of the fire cycle or during periods of extended drought, or insect infestations. In general, a mix of age classes should be expected with some dead and decadent plants present not exceeding 5%.

14. Average percent litter cover (%) and depth ( in):

    Litter cover will be heavier under plants. Most litter will be herbaceous and depths of 1/2 to 1 inch would be considered normal. Perennial vegetation should be well distributed on the site.

15. Expected annual annual-production (this is TOTAL above-ground annual-production, not just forage annual-production):

    Annual production in air-dry herbage should be approximately 900 - 1100 #/acre on an average year, but could range from 700 to 1400#/acre during periods of prolonged drought or above average precipitation.
    

16. Potential invasive (including noxious) species (native and non-native). List species which BOTH characterize degraded states and have the potential to become a dominant or co-dominant species on the ecological site if their future establishment and growth is not actively controlled by management interventions. Species that become dominant for only one to several years (e.g., short-term response to drought or wildfire) are not invasive plants. Note that unlike other indicators, we are describing what is NOT expected in the reference state for the ecological site:

    Cheatgrass, Russian thistle, Utah juniper, and non-native invasive annual forbs such as mustards or halogeton.

17. Perennial plant reproductive capability:

    All perennial plants should have the ability to reproduce in all years, except in extreme drought years. Green rabbitbrush sprouts vigorously following fire. There are no restrictions on either seed or vegetative reproduction. Some seedling recruitment of major species is present during average and above average growing years.

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