Emergency 

Rehabilitation and 

Restoration Planning in a Variable 

Environment

By Stuart P. Hardegree, Plant 

Physiologist and Research Leader

USDA, Agricultural Research 

Service, Northwest Watershed 

Research Center

Background

Water availability is a primary 

determinant of successful plant 

establishment on western rangelands. Two major factors that 

determine water availability are 

seasonal and annual patterns of 

precipitation and the presence of 

competitive annual weeds. In the 

Intermountain West, the most 

prolific invasive weed has been 

cheatgrass (Bromas tectorum L.), 

which now dominates millions of 

acres of sagebrush and bunchgrass 

rangeland. Restoration practices in 

systems affected by cheatgrass have 

generally been limited to emergency rehabilitation procedures 

(primarily soil stabilization) in the 

year after wildfire. Species selected 

for fire rehabilitation have historically included highly productive 

and competitive non-native grass 

species. Present policies include 

objectives for plant community 

restoration and encourage the 

use of native plant materials. The 

high level of climatic variability in 

both time and space, and the presence of highly competitive annual 

weeds, however, may preclude 

simultaneous achievement of both 

soil stability and native plant–biodiversity objectives in most years. 

Recent research at the USDA 

Agricultural Research Service, 

Northwest Watershed Research 

Center (NWRC; Boise, Idaho) 

provides a probabilistic framework 

for making species selection decisions and for incorporating knowledge of climate variability and 

forecasting into revegetation and 

restoration planning.

Discussion

The NWRC operated a seedbedmicroclimatic monitoring network 

in the Snake River Plain of Idaho 

for most of the 1990s. Staff measured soil temperature and moisture and hourly weather variables 

of air temperature, humidity, solar 

radiation, wind speed, and precipitation. These data were used to 

calibrate a seedbed-microclimatic 

model that predicted water availability and temperature at seeding 

depth and ran simulations with 

38 years of weather data from 

southern Idaho. These simulations yielded hourly estimates of 

seedbed microclimate, which were 

used as input into a hydrothermal 

germination-response model for 

cheatgrass; bluebunch wheatgrass, 

Pseudoroegneria spicata (Pursh) A. 

Löve; and big squirreltail, Elymus 

multisetus M.E. Jones. Scientists 

were then able to ask the question: 

What would have happened if we 

had planted these seedlots on any 

particular day in the last 38 years? 

The data from these model simulations not only let us develop new 

indices for evaluating seedlots, but 

also let us establish probabilistic 

descriptions of potential establishment success in different types of 

precipitation years.

The data supported some obvious and expected conclusions. 

Cheatgrass germinated more 

rapidly under almost any climatic 

scenario. In general, the most 

favorable periods for rapid germination occurred in spring when 

both water and temperature were 

favorable for cheatgrass establishment. Temperature patterns were 

relatively consistent from year to 

year, and germination success was 

mostly determined by the pattern 

of water availability at seeding 

depth, which was highly variable. 

These results were not unexpected. 

The new information generated by 

these data, however, resulted from 

quantifying the relative effect of 

different weather patterns on establishment success and in providing 

insight into the incorporation 

of climate information into revegetation and restoration decision 

making. 

In an idealized scenario of perfect 

weather foreknowledge, these modeling tools could be used to assist 

in the following decisions for both 

rehabilitation planning in fire years 

and restoration planning in nonfire years: 1) In an extremely dry 

year, is it prudent to use cheatgrass 

control measures when it would be 

difficult to establish either native 

or non-native perennial grasses 

for soil stabilization? 2) In a relatively dry year, is it prudent to seed 

native species that would be difficult to establish regardless of cheatgrass control measures? 3) Should a 

combination of cheatgrass control 

and native plant seeding be limited 

to wet-establishment years when 

there is a relatively high probability 

of success?

Conclusion

Weed competition and drought 

considerations have previously 

served as justification for use of 

non-native plant materials as a 

generic prescription for rangeland 

revegetation and rehabilitation. 

NO. 71 DATE 08/23/04

Range

Range

Resource Note 71

Page 1
A new generic prescription for 

exclusive use of native plant materials for fire rehabilitation may 

not be realistic in many years. 

Unfortunately, weather forecasting 

models for Intermountain rangelands presently consist of synoptic 

descriptions of historical climate 

probabilities and are not based 

on either physical or empirical 

predictions of future weather patterns. As weather forecasting tools 

improve, it may be possible to 

establish climatic criteria for choosing between native and non-native 

plant materials for fire rehabilitation, and to decide when to initiate 

contingency plans for restoration 

of native-dominated plant communities in nonfire years. As we 

await better forecasting tools, it 

would be extremely useful for 

revegetation and restoration planners to include detailed local and 

regional weather information when 

they document present and historical patterns of establishment success. It is especially important to 

include documentation of seeding 

failures. Additional field data are 

also needed to determine the relative feasibility of transitioning from 

cheatgrass to a native-dominated 

system through the intermediate 

step of a non-native perennial plant 

community. Present restoration 

planning strategies tend to focus 

on the—perhaps more difficult—

direct transition between a cheatgrass and native-plant system state. 

Contact 

Stuart Hardegree 

USDA, Agricultural Research 

Service

800 Park Boulevard, Suite 105

Boise, ID 83712

Phone: 208-422-0728

Email: shardegr@nwrc.ars.usda.gov

Additional Literature

Hardegree, S. P., G. N. Flerchinger, and S. S. Van Vactor. 

2003. Hydrothermal germination 

response and the development of 

probabilistic germination profiles. 

Ecological Modeling 167(2003):

305–322. 

Range

Resource Note 71

Page 2

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