Ecological Sustainability Report for the Kiowa, Rita Blanca, Black Kettle and McClellan Creek 

National Grasslands – Appendix F

APPENDIX F – Vegetation Departure from Reference Conditions

Appendix F supplements the information found in the Ecosystem Diversity section of the 

Ecological Sustainability Report for the Kiowa, Rita Blanca, Black Kettle and McClellan Creek 

National Grasslands. Specifically, it outlines the current and reference conditions for shortgrass 

prairie, pinyon-juniper, cottonwood-willow riparian, sand sagebrush, mixed-grass prairie, 

shinnery oak, and mixed hardwood riparian vegetation types. The information in the following 

tables was used to determine the percent of departure from reference condition. There are three 

classes of departure for this evaluation:

1. Low departure

2. Moderately departed

3. Severely departed

In order to determine the percentage of departure from reference condition for a vegetation type, 

the mid-scale vegetation found within each vegetation type was placed into a Successional Class 

Structure1category based on the information in the reference condition model being used for the 

evaluation. A comparison was then made of the current percentage to the reference percentage 

for each successional class within the model. The lesser of the two percentages (current vs. 

reference) was subtracted from 100 for each successional class. The resulting number determined 

the level of departure.

1. 0-33 = Low departure

2. 34-66 = Moderately departed

3. 67-100 = Severely departed

For example, the cottonwood-willow riparian vegetation has two classes identified. There is 

currently 16% in the early class and 84% in the mid and late class. The reference condition is 

20% for the early class and 80% for the mid/late. To calculate the departure, start with 100 

percent and subtract the lesser amount for each class.

100

Early -16

Mid/Late -80

Departure 4

The departure number is four, meaning that this vegetation type has a low departure from the

reference condition.

 

1 Weisz, R; Triepke, FJ; and Truman, R. 2009. Evaluating the ecological sustainability of a 

ponderosa pine ecosystem on the Kaibab Plateau in northern Arizona. Fire Ecology 5(1): 100-

114.
Ecological Sustainability Report for the Kiowa, Rita Blanca, Black Kettle and McClellan Creek 

National Grasslands – Appendix F

Mixed-grass Prairie Current 

Percent

Reference 

Percent Successional Class Structure and Composition

Early: 1-3 years postfire. Resprouting grasses especially postrain. Species include blue grama, buffalograss, hairy grama, 

sideoats grama and little bluestem.

35% 30%

Mid/Late: Greater than 3 years post-fire. Lower diversity of forbs 

and lower productivity. Woody species may encroach in the 

absence of fire.

65% 70%

Mixed-grass Prairie = 7 (low departure from reference condition)

Shinnery oak Current 

Percent

Reference 

Percent Successional Class Structure and Composition

Early/Mid-Open: Post-fire to three years post-fire. Dominated 

by tallgrasses in shallower and more stable sandsheet areas. 

Grass cover dominant with rapid recovery of shinnery oak 

resprouts.

45% 23%

Late/Closed: Three to ten years post-fire. Shinnery cover 

mostly dominant although grasses remain codominant. 55% 77%

Shinnery oak = 25 (low departure from reference condition)

Shortgrass Prairie Current 

Percent

Reference 

Percent Successional Class Structure and Composition

Early: Dominated by resprouts and seedlings of grasses and postfire associated forbs. Species include blue grama and 

buffalograss.

2% 5%

Mid-Open: Less than 35 percent herb cover. Low to medium 

height. Main grasses are blue grama and buffalograss. 90% 65%

Mid-Closed: Greater than 35 percent herb cover. Main grass 

species are blue grama and buffalograss. 8% 30%

Shortgrass Prairie = 22 (low departure from reference condition)
Ecological Sustainability Report for the Kiowa, Rita Blanca, Black Kettle and McClellan Creek 

National Grasslands – Appendix F

Pinyon-Juniper Current 

Percent

Reference 

Percent Successional Class Structure and Composition

Early: Open with grasses, forbs, seedlings and saplings. Usually 

occurs post-fire. 12% 10%

Mid/Late: A mix of pinyon and juniper trees in a variety of 

classes with varying canopy cover. Mid-development classes 

averages 10% of the PNVT in relative abundance and has dense 

canopy cover (31-70%) of pole size trees (5-9” in diameter) and 

very little understory. 25% of the PNVT will have pole size 

trees with a mixed shrub/herbaceous understory and canopy 

cover ranges from 0-30%. 35% of the PNVT will have late 

development with medium size trees (9-21” in diameter) and 

canopy cover of 0-40%. 10% of the PNVT will have dense, old 

growth characteristics with medium size trees and canopy cover 

of 41-70%.

88% 90%

Pinyon-Juniper = 2 (low departure from reference condition)

Cottonwood-Willow Riparian Current 

Percent

Reference 

Percent Successional Class Structure and Composition

Early: This class is typically shrub/seedling-dominated, but 

grasses may co-dominate. 16% 20%

Mid (25%): Vegetation composition includes tall shrubs and 

small trees (willows & cottonwoods).

Late (55%): This class represents the mature, large cottonwood

and willow riparian woodlands.

84% 80%

Cottonwood-Willow Riparian = 4 (low departure from reference condition)
Ecological Sustainability Report for the Kiowa, Rita Blanca, Black Kettle and McClellan Creek 

National Grasslands – Appendix F

Mixed hardwood Riparian Current 

Percent

Reference 

Percent Successional Class Structure and Composition

Early: Pioneer tree and shrub species of cottonwoods and 

willows. Herbaceous understory of sedges in wet areas. In this 

early stage, most of the area is bare sand. Dominated by young 

canopy of tree saplings and shrubs. Species would include 

indigo bush and various grass, sedges, and rushes.

13% 20%

Mid (25%): This stage develops as the stand starts to mature. 

This community tends to be partially opened, with scattered 

cottonwoods and willows. The shrub layer is poorly developed 

and often consists of widely scattered patches of dogwood. The 

understory vegetation is highly variable with wild rye, and 

muhlies. In wetter, more shaded areas Virginia creeper, nettles, 

and poison ivy would exist.

Late (55%): This class is a mature, late seral closed canopy 

cottonwood floodplain forest. Overstory is dominated by 

cottonwood, box elder, hackberry, walnut and elm. Understory 

species composed of Virginia creeper, and poison ivy. Found 

along the upper terrace that has been protected from most flood 

events, except for rare high intensity flooding.

87% 80%

Mixed hardwood Riparian = 7 (low departure from reference condition)

Sand sagebrush Current 

Percent

Reference 

Percent Successional Class Structure and Composition

Early: Dominated by resprouts and seedlings of grasses and forbs. 

Low to medium height with variable canopy cover. 1% 1%

Mid-Open: Less than 35% herb cover. Medium to tall height. 69% 55%

Mid-Closed: Greater than 35% herb cover. Medium to tall height. 30% 44%

Sand sagebrush = 14 (low departure from reference condition)