Pacific Forest and Basin Rangeland Systems

Cooperative Research and Technology Unit

Techni cal Note

United States

Department of the Interior

Oregon State Office

P.O. Box 2965

Bureau of Land Management Portland, Oregon 97208

TIN: OR-936-01 Date: February 1993

PROBLEM ANALYSIS FOR THE

VEGETATION DIVERSITY

PROJECT

David A. Pyke, Senior Rangeland Ecologist; Michael M. Borman,

Rangeland Ecologist
U.S. Department of the Interior

Bureau of Land Management

PROBLEM ANALYSIS

FOR

THE VEGETATION DIVERSITY PROJECT

A Research and Demonstration Program to Restore and

Maintain Native Plant Diversity on Deteriorated

Rangelands of the Great Basin and

Columbia Plateau

Prepared by

David A. Pyke and Michael M. Borman

Senior Rangeland Ecologist and Rangeland Ecologist

Pacific Forest and Basin Rangeland Systems

Cooperative Research and Technology Unit

Corvallis, Oregon 97331

Approved by:

__ Michael J. Penfold Penfold

Assistant Director

Lands and Renewable Resources
Executive Summary

Management of the majority of public rangeland in the

Great Basin and Columbia-Snake River Plateau falls

under the authority of the Bureau of Land Management. The flora of this land ranges from highly diverse

native plant communities to deteriorated lands dominated by exotic annuals. Approximately nine percent of

the BLM’s 78 million acres of public land in this region

is degraded to such a degree that changes in land

management alone will not result in significant improvement. The BLM intends to restore native plant

communities on these deteriorated lands, but current

revegetation techniques used to establish introduced

perennial grasses are often unsuccessful in establishing native plants.

On lands where native communities exist, the BLM

desires to maintain and to enhance native plant

diversity. Encroachment of highly competitive exotic

forbs and annual grasses in native plant communities

raises concern among managers over the appropriate

management to maintain native communities. Coupled

with these concerns are impacts on vegetation of the

documented increase in CO, and of predicted global

climate change. The BLM therefore recognizes the

need for research to understand and solve these

problems and for the results of this research to be

transferred to land managers.

The Great Basin and Columbia Plateau region consists

of two major ecosystems: the sagebrush ecosystem,

generally located in the northern half of the region; and

the salt-desert shrub ecosystem, located in the southern half. These ecosystems differ greatly in their

composition of plant species and in their climatic and

soil conditions. Therefore, techniques developed in

one ecosystem may not be directly transferred to the

other ecosystem.

We propose to initially concentrate studies in the

Wyoming big sagebrush communities of the sagebrush

ecosystem, because: (1) these communities represent

a large amount of the BLM lands in Oregon, Idaho,

northeastern California, Nevada and Utah; and (2) the

low precipitation within these communities limits the

success of standard revegetation methods. Shadscale

communities of the salt-desert shrub ecosystem were

given the next priority for study. These communities

are a major component in four of the five participating

states. Since the shadscale communities differ greatly

from sagebrush communities, studies of shadscale

communities will be initiated when the project reaches

full funding. Similar studies to those proposed here for

sagebrush communities would be conducted on this

new suite of species and environmental conditions.

Low sagebrush communities would be given the lowest

priority and are unlikely to be initiated. Plant associations in low sagebrush and Wyoming sagebrush

communities are similar and thus promising techniques

for the Wyoming sagebrush communities may work

well in low sagebrush communities and may be

attempted later in the project.

The studies fall under five major areas of investigation:

(1) Long-term monitoring of vegetation diversity; (2)

Competition and establishment; (3) Plant materials and

seed technology; (4) Maintenance of desired native

vegetation; and (5) Special status plants. Under each

area of investigation a series of high, medium and low

priority studies have been identified. The priorities will

be used as a guide in preparing requests for proposals,

and in selecting and funding studies through the

duration of the project.

Funding levels will determine the number and scope of

studies conducted. Under the initial funding level, only

six to eight studies from among the high priority studies

can be initiated.

Long-term monitoring plots would be established

throughout the Great Basin to detect the effects of

yearly variation in climate on the species composition,

productivity, and structural diversity of plant communities with and without grazing. In conjunction with these

plots, long-term studies would be conducted relating

climatic variations and livestock use to the survival,

reproduction, and seedling establishment of important

native perennials.

Competition between exotic annuals and native

perennials would be quantified and documented in

controlled environments and in field studies. The role

of elevated CO, levels and of precipitation shifts on the

competitive relationship between desirable and undesirable plants should be examined.

Alternative methods to the standard rangeland drill

technique would be examined for establishing species

in wilderness areas or for establishing species that

require intensive techniques for successful establishment.

The need for local seed sources to restore native

vegetation should be examined in a study to compare

the genetic variability with the environmental variability

(phenotypic plasticity) within desirable native species.

A high degree of genetic variability within a species

would strongly suggest the need for collecting seeds of

restoration species from nearby rather than distant

populations.

i
Studies concerning the maintenance of desired native soil conditions and on species from similar genera or

vegetation would examine the conditions required for from similar growth forms.

exotic species to successfully invade and maintain

populations in stands of diverse native vegetation. Information gathered from these studies and from

studies conducted by BLM district personnel will be

Studies of special status plants will focus initially on transferred to land managers using a quarterly newscollecting critical life history data (survival, seed letter, demonstration sites, development or use of

production, seed bank persistence, germination and computer expert systems and through peer reviewed

establishment) on species not restricted to specialized scientific journals.

ii
Acknowledgments

Several individuals have contributed to the development of the Vegetation Diversity Project. We recognize the

foresight of the three Oregon/Washington BLM District Offices, Burns, Spokane, and Vale, that initially identified a

need for research on revegetation of semiarid rangelands using native species. We acknowledge the efforts of J.

Asher in recognizing, organizing, and developing a multistate BLM research project plan. We acknowledge the

efforts of other federal, state and university people who participated in workshops and committees and who made

recommendations that were incorporated into this project.

We thank personnel from BLM State and District Offices in California, Idaho, Nevada, Oregon, Utah, and Washington who participated in personal interviews concerning the management priorities for research. We also thank

research scientists from the Agricultural Research Service at Boise, ID, Logan, UT and Reno, NV, from the US

Forest Service Forestry Sciences Lab in Reno, NV and the Shrub Sciences Lab in Provo, UT, from the Soil Conservation Service Plant Materials Center Aberdeen, ID, and from the Desert Research Institute in Reno, NV who

provided information on current research relevant to the project. We thank faculty members from Boise State

University, Brigham Young University, Idaho State University, Oregon State University, University of Idaho, University of Nevada-Reno, Utah State University, and Washington State University for their insights into their current

research and for recommending research priorities.

We thank the following people from the BLM who critically reviewed an earlier draft of this document: J. Asher, S.

Beverlin, S. Coloff, W. Elmore, C. Fanning, D. Harmon, R. Lund, L. Maxfield, C. McCaffrey, J. McAufflin, M. Pellent,

V. Pritchard, D. Smith, L. Walker, and D. Webb. We are grateful for the critical review of an earlier draft by the

following scientists who are familiar with the problems associated with ecosystem restoration in the Great Basin and

Columbia-Snake River Plateau: E. B. Allen, J. E. Anderson, M. R. Haferkamp, K. T. Harper, M. Karl, J. W. Menke,

B. E. Olson, and P. T. Tueller.

iii
iv

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Table of Contents

Introduction ........................................................................................................................................... 7

Literature Review.................................................................................................................................... 9

I. Ecosystem Descriptions ........................................................................................................ 9

 A. Sagebrush Ecosystems.................................................................................................... 10

 B. Salt-Desert Shrub Ecosystems ........................................................................................ 11

II. Vegetation Dynamics .......................................................................................................... 12

III. Competition and Establishment .......................................................................................... 14

 A. Factors in Competition .................................................................................................. 14

 B. Climate Change and Competition .................................................................................. 17

 C. Controlling Competition ................................................................................................ 18

 D. Establishment Islands.................................................................................................... 29

IV. Plant Materials and Seed Technology .................................................................................. 29

 A. Ecotypic Adaptation vs. Phenotypic Plasticity................................................................. 29

 B. Seed Treatment.............................................................................................................. 31

 C. Seeding Techniques....................................................................................................... 32

 D. Legume Innoculation..................................................................................................... 34

 E. Mycorrhizal Funi Innoculation ........................................................................................ 34

V. Maintenance of Native Plant Diversity ................................................................................. 34

 A. Demography.................................................................................................................. 34

 B. Herbivory....................................................................................................................... 35

 C. Fire................................................................................................................................ 35

 D. Climate.......................................................................................................................... 35

VI. Special Status Plants ........................................................................................................... 36

VII. Concerns of Land and Resource Managers.......................................................................... 37

Technology Transfer............................................................................................................................. 38

Research and Demonstration Tasks...................................................................................................... 39

I. Plant Communities for Study............................................................................................. 39

 A. P1 - Wyoming Big Sagebrush......................................................................................... 39

 B. P2 - Shadscale ............................................................................................................... 39

 C. P3 - Low and Black Sagebrush....................................................................................... 39

II. Long-term Monitoring of Biological Diversity...................................................................... 40

 A. Diversity Across the Great Basin .................................................................................... 40

III. Com petition and Establishment ......................................................................................... 41

 A. Competition .................................................................................................................. 42

 B. Island Establishment...................................................................................................... 45

 C. Specialized Methods for Establishment......................................................................... 45

 D. Prescribed Fire to Control Competitors.......................................................................... 46

v
 E. Nutrient Availability and Competition ............................................................................ 47

 F. Animals as Agents of Biocontrol and Stimulatory Growth............................................... 47

IV. Plant Materials and Seed Technology .................................................................................. 48

 A. Ecotypes and Phenotypes ............................................................................................... 48

 B. Problem Diaspores.......................................................................................................... 50

 C. Seed Priming .................................................................................................................. 50

V. Maintenance of Desired Native Vegetation........................................................................... 50

 A. Demography and Life History ......................................................................................... 51

 B. Establishment of Undesirable Species ............................................................................. 51

 C. Management for Desirable Communities........................................................................ 52

VI. Special Status Plants ........................................................................................................... 53

 A. Demographic Studies of Special Status Plants................................................................. 53

 B. Special Status Plant Restoration ...................................................................................... 53

Literature Cited .................................................................................................................................... 55

Appendices........................................................................................................................................... 67

Commercial Seed Sources ......................................................................................................... 69

Cultural Practices...................................................................................................................... 77

 Grasses................................................................................................................................ 77

 Forbs ................................................................................................................................... 78

 Shrubs ................................................................................................................................. 79

Seed Testing ............................................................................................................................. 83

Seed Storage............................................................................................................................. 85

Seed Treatment Studies ............................................................................................................ 87

Noxious Weeds ......................................................................................................................... 89

Concerns of Land and Resource Managers................................................................................ 97

vi
Introduction

The Great Basin and Columbia-Snake River Plateau

are generally recognized as the geological boundaries

of the Intermountain Region of the US. These lands

are bounded by the Cascade and Sierra Nevada

Mountains on the west and by the Rocky Mountains on

the east and extend from the Canadian border in the

north to the extremely arid environments of the

Mohave and Sonoran Deserts of Nevada and Arizona.

The vegetation supported by these lands is generally

described as a shrub-steppe.

The Vegetation Diversity Project will target portions of

the Great Basin and the Columbia-Snake River

Plateau. Bureau of Land Management (BLM) managed lands within this target area include eastern

Oregon, southern Idaho, western Utah, the northern

two-thirds of Nevada, northeast California, and a small

portion of California’s Bishop Resource Area north of

Owens Dry Lake.

Climatically, the region is characterized as semiarid

with mean total precipitation ranging from 180 to 410

mm (7 to 16 in.). Most of the precipitation (70 to 80 %)

comes during the winter as snow. Gradual snow melt

allows infiltration of the moisture into the soil. The

perennial plants that dominate the system utilize this

moisture in the late-winter and spring for growth and

reproduction.

Climatic shifts caused past vegetational shifts within

this region. The periods of Pleistocene glaciation likely

reduced summer temperatures and increased total

precipitation resulting in conifer forests on the foothills

and on valley bottoms that were not covered by lakes

(Wells 1983). During warmer interglacial periods trees

died while grasses and shrubs expanded back into the

valleys and foothills. Less dramatic climatic and

vegetational shifts were seen during the Holocene

(Mehringer 1977, Thompson 1990).

Aboriginal humans may have caused vegetational

changes by reducing browsing animals (Mehringer

1977) or through local overuse of areas (Samuels and

Betancourt 1982), but larger changes can be traced to

the last 150 years of occupancy by humans of European descent. European man began to settle this

region during the mid-1800s. These early settlers

intentionally and accidentally introduced plants from

Europe and Asia (Mack 1986). Overgrazing by

livestock occurred throughout the region from the late1800s to the mid-1900s and led to a degradation of

native vegetation on public rangelands over much of

the region. The void left by the loss of native plants

allowed introduced plants and less palatable native

plants to rapidly expand and dominate many areas.

Better grazing management has resulted in a reduction

in grazing pressure and many improvements in vegetative composition and production of rangelands, but the

loss of structural, functional, and species diversity

within some of the native plant communities will require

additional research to provide managers with sufficient

information to facilitate recovery of deteriorated sites.

Management of the majority of public rangelands in the

Great Basin and Columbia-Snake River Plateau falls

under the authority of the BLM. Flora of BLM lands

ranges from highly diverse native rangeland to deteriorated lands dominated by exotic annuals. For example, approximately nine percent of the BLM’s 78

million acres of the public lands in this region are

degraded to such a degree that changes in livestock

management alone will not result in significant improvement. The BLM intends to restore native plant

communities on selected areas that are currently

deteriorated when native plant restoration is consistent

with current land use plans. However, current revegetation techniques used to establish introduced

perennial grasses have often been unsuccessful when

attempting to restore native perennials. Where native

communities exist, the BLM desires to maintain and

enhance the diversity within these communities.

However, encroachment of highly competitive exotic

weeds into native plant communities raises a concern

among managers over appropriate management to

maintain native communities. Coupled with these

concerns are impacts of the documented increase in

CO, and of predicted global climate change on vegetation. The BLM therefore recognizes the need for

research to understand and solve these problems and

for technology transfer of research results to land

managers to improve and maintain native plant diversity.

In preparing for this problem analysis, a workshop was

convened (Krueger et al. 1989) to gain input from

researchers and managers about current recommendations and research needs to accomplish the goal of

restoring and maintaining diverse native plant communities in the Great Basin and Columbia-Snake River

Plateau. After two BLM research scientists were hired,

meetings were arranged between the scientists and

participating BLM state offices (Idaho, Nevada, Oregon-Washington, Utah, and California), between the

scientists and the five Oregon-Washington BLM district

offices, and between the scientists and current research scientists in the Great Basin and ColumbiaSnake River Plateau to provide additional input on

needs for research.

7
In this problem analysis, we will review the literature summarize the prioritized needs of the BLM managers.

and document on-going studies concerning diversity, From this information base, we will prioritize the

restoration, and maintenance of native vegetation in research and demonstration tasks that the project will

the Great Basin and Columbia-Snake River Plateau. address and we will discuss methods of transferring

The review of the literature is not intended to be pertinent information to land managers for application

exhaustive but is intended to highlight some of the in BLM districts in the Great Basin and Columbiabackground information critical to this project. We will Snake River Plateau.

8
Literature Review

and On-Going

Studies

I. Ecosystem Descriptions

The Great Basin and Columbia Plateau region covers

two major physiographic provinces: (1) the ColumbiaSnake River Plateau Province in eastern Washington,

Oregon, and southern Idaho; and (2) the Basin and

Range Province in southcentral Oregon, northeastern

California, Nevada, and western Utah (Hunt 1974) and

incorporates four ecoregions with their associated

vegetation (Omernik 1986, 1987): (1) Columbia Basin,

(steppe and shrub-steppe); (2) Blue Mountains (mixed

forest and shrub-steppe); (3) Snake River Basin/High

Desert (sagebrush steppe); and (4) northern Basin and

Range (sagebrush and salt-desert shrub)(Fig. 1).

These two provinces differ in their underlying bedrock.

The Columbia-Snake River Plateau was formed by

lateral flows of basaltic lava during the Miocene and

Pliocene. The loessal soil varies in depth depending

on the time exposed to deposition and removal. The

Basin and Range Province is characterized by a series

of north-south tending valleys and fault-block mountain

ranges. The soils are a combination of loessal, alluvial,

or lacustrine fill. During the Pleistocene, lakes occupied many of the valleys in the Great Basin. Currently,

these valleys are hydrologically closed basins lacking

drainage to the sea and tending to have more alkaline

soils than the Columbia-Snake River Plateau.

Vegetation types found in the Intermountain West

range from steppe to shrub-steppe to xeric woodlands.

For purposes of narrowing the focus of this project,

juniper woodland sites will not be considered. Although there are many problems requiring research in

juniper ecosystems, such as the encroachment of

juniper into formerly sagebrush dominated sites and

the effects on watershed stability of juniper dominance,

this project will concentrate on problems of shrubsteppe communities. Kuchler (1970) describes six

zonal potential natural vegetation systems for the

Great Basin and Columbia Plateau. We will use these

described ecosystems as a general overview.

Two steppe ecosystems are found on the Palouse

Prairie of Washington and Oregon. The fescuewheatgrass (Festuca-Agropyon) type is restricted to

the mesic, deep soil sites of eastern Washington. The

wheatgrass-bluegrass (Agropyron-Poa) type occurs on

shallower soils than the fescue-wheatgrass type and is

found in southeastern Washington and in a narrow

band in northeastern Oregon (West 1988). Lands

within these ecosystems tend to be privately owned

and will not be discussed further in this analysis.

Two sagebrush ecosystems dominate the majority of

the region. The sagebrush steppe (woody Artemisia)

is the largest ecosystem covering nearly 45 million ha

including portions of southcentral Washington, most of

eastern Oregon, southern Idaho, northern California,

and the northern edges of Nevada and Utah. The

majority of the ecosystem lies within the ColumbiaSnake River Plateau, although it extends into the

northern portion of the Basin and Range Province.

The Great Basin sagebrush ecosystem occupies most

of eastern Nevada and occurs throughout central and

southern Utah. West (1983a) indicates that these two

ecosystems are closely related and are largely separated because the more arid Great Basin sagebrush

ecosystem is less likely to recover following disturbances than the sagebrush steppe.

Figure 1. Map depicting the location of the four ecoregions of the

western United States that outline the study area for the Vegetation

Diversity Project. The Columbia Basin, Blue Mountains, and the

northern half of the Snake River Basin/High Desert ecoregions lie

within the Columbia-Snake River Plateau physiographic province.

The Basin and Range, and the southern half of the Snake River

Basin/High Desert ecoregions lie within the Basin and Range

physiographic province (Hunt 1974, Omernik 1986).

9
The last major ecosystem within the region is the saltdesert shrubland. This ecosystem is dominated by

shrubs and half-shrubs of the Chenopodiaceae such

as shadscale (Atriplex confertifolia) and winterfat

(Ceratoides lanata). Although the ecosystem’s name

would indicate saline soils, this is not the rule for the

entire ecosystem. Chenopod shrubs dominate nonsaline soils in arid regions of Nevada east of the SierraNevada Mountains (Billings 1949). Physiographically,

this ecosystem is largely restricted to the Basin and

Range Province with two-thirds of its area found in

Nevada and Utah (West 1983b).

Most of the BLM lands in the Great Basin and Columbia Plateau lie within the two sagebrush ecosystems

and the salt-desert shrubland ecosystem. We will

describe in more detail below the important plant,

animal and microbial components of these ecosystems.

A. Sagebrush Ecosystems

The sagebrush ecosystem is the highest priority

system for BLM lands of the Great Basin and Columbia

Plateau because of the extent of coverage and because of the identified management concern within

most State BLM offices (see Concerns of Land and

Resource Managers ). Although big sagebrush (Artemisia tridentata) is the dominant shrub in plant associations, three subspecies may occur depending on the

soils, available moisture, and soil temperature (elevation). Wyoming big sagebrush (A. t. wyomingensis)

grows on arid, warm soils on lowland sites. Mountain

big sagebrush (A. t. vaseyana) grows on mesic, cool

soils at higher elevations, whereas basin big sagebrush (A. t. tridentata) is found on sites with intermediate characteristics (West 1979, Hironaka et al. 1983,

Winward 1983) or on deep soils or on soils with

enhanced water availability (J.E. Anderson, pers.

comm.). Regardless of the subspecies, descriptions

are similar of big sagebrush in relatively undisturbed

communities. Canopy coverage averages 15% (range

4 to 25%) for A.t. wyomingensis and A.t. tridentata and

20% for A.t. vaseyana with sagebrush composing

about 10% (range 4 to 20%) of the total vegetation

cover or biomass (Hall 1973, Mason 1978, Bunting et

al. 1987).

The herbaceous component of these communities is

dominated by perennial bunchgrasses such as

bluebunch wheatgrass (Pseudoroegneria spicata

formerly Agropyron spicatum), Sandberg’s bluegrass

(Poa sandbergii), and Idaho fescue (Festuca

idahoensis). Other grasses that are often less prominent in less disturbed communities are squirreltail

(Sitanion hystrix), needle-and-thread (Stipa comata),

and Thurber’s needlegrass (Stipa thurberiana). Idaho

fescue occurs on the more mesic sagebrush sites,

whereas bluebunch wheatgrass is common to all of the

sites (Franklin and Dyrness 1973). Stipa spp. become

more abundant further south in the region (Nevada and

Utah). On sandy soils, Indian ricegrass (Oryzopsis

hymenoides) may occur in association with sagebrush

and bluebunch wheatgrass.

The perennial forb component of the sagebrush steppe

is represented by a wide variety of species. In eastern

Washington, canopy coverage for perennial forbs

averages 7% and contributes about 4% of the total

plant coverage (Daubenmire 1970). Some common

species in this community are long-leaved phlox (Phlox

longifolia), hooker’s onion (Allium acuminatum), and

shaggy fleabane (Erigeron pumilus).

Those areas of the soil surface not covered by vascular plants are often covered by a fragile cryptogamic

crust of lichens and mosses. Daubenmire (1970)

provides a list of 15 genera of lichens and mosses

identified in pristine sagebrush communities in eastern

Washington. Repeated soil disturbance leads to a

reduction in the crust.

Dwarf sagebrush species (Artemisia arbuscula, A.

longiloba, and A. nova) replace big sagebrush as the

dominant shrub on shallow soils within this ecosystem

in southern Oregon, northern Nevada, and southern

Idaho. Soil characteristics appear to determine the

dwarf sagebrush that will dominate the site. Either A.

arbuscula or A. longiloba dominates sites with

noncalcareous soils or with a dense clay horizon

between 5 and 30 cm below the soil surface. In

contrast, A. nova is found on sites with calcareous soils

in Nevada (Zamora and Tueller 1973), but is located ’

on shallow soils overlying basalt flows in Idaho (J.E.

Anderson, pers. comm.).

The dominant grasses and forbs of dwarf sagebrush

communities are similar to those found in the big

sagebrush communities. Coverage of Idaho fescue

and bluebunch wheatgrass are less than their equivalent big sagebrush counterparts, whereas Sandberg’s

bluegrass is slightly higher in coverage (Culver 1964).

Loss of one or several components of the structural

diversity (e.g., shrubs, forbs, or grasses) is a major

concern to managers (see Concerns of Land and

Resource Managers below). Techniques for the

reintroduction of these components without eliminating

the intact components are desired. Severe disturbances often encourage the spread and dominance of

exotic weedy species.

10
These exotic species, such as cheatgrass (Bromus

tectorum) and medusahead (Taeniatherum caputmedusae), are often represented in relatively undisturbed communities, but tend to remain as subordinate

species (approx. 5% or less canopy coverage). With

disturbance, these grazing-tolerant or grazing-avoiding

competitive species can quickly expand and dominate

sites. The role of climate (e.g. shifts between drought

and favorable moisture conditions) in dictating potential

expansion of these species is not well understood.

Concern has been expressed by James A. Young

(USDA-ARS, Reno, personal communication) over the

potential surge in medusahead dominance once the

current region-wide drought ends.

Overgrazing and frequent wildfires have led to the

dominance of cheatgrass on over 40 million ha (99

million ac) in the Intermountain West (Mack 1981). On

some sites in northeastern California and northwestern

Nevada, plant dominance has shifted from cheatgrass

to medusahead and later to one of the knapweeds,

yellow starthistle (Centaurea solstitia/is) (pers. comm.

J.A. Young). Research is needed to identify native

species which can be established as a single species

or as combinations which are competitive with these

exotic weeds. We also need to understand how

livestock utilization of natives may affect the exotic

species.

Woody vegetation within this ecosystem tends to

create areas of greater nutrient concentrations, ‘islands

of fertility’ (see review by West 1991). Woody plants

remove nutrients from surrounding interspaces and

distribute it in the form of litter beneath their canopies.

Shrubs also provide structural diversity within communities which enhances the capture of vesiculararbuscular mycorrhizae (VAM) spores (Allen and

MacMahon 1985) and of snow (Allen et al. 1987). As a

consequence, microbial and animal activity associated

with nutrient cycling is often concentrated in these

patches.

VAM are associated with most dominant native perennials within arid and semiarid lands (Miller 1979,

Trappe 1981) and may enhance nutrient and water

uptake by plants (Harley and Smith 1983, Allen and

Boosalis 1983). The presence of VAM in disturbed

sagebrush ecosystems may enhance the restoration of

native perennials by increasing the capacity of the

perennials to capture resources when competing with

nonmycorrhizal or facultatively mycorrhizal exotic

annuals (Allen 1988). However, site preparation

techniques that disturb the soil may reduce the likelihood of infection because these techniques destroy the

mycelial network that formerly existed (Evans and

Miller 1990).

Successful restoration may require creating artificial

islands that simulate the structural and functional

conditions that shrubs create in the ecosystem. This

may require the use of structures such as snowfences

and mulch to enhance the restoration of some natives.

B. Salt-Desert Shrub

Ecosystems

The presence of dominant species throughout this

ecosystem is largely dictated by soil salinity levels.

Although presence of a species is not a useful indicator

of soil salinity because of the wide range of tolerances

among species (Gates et al. 1956), there is an accepted trend that as salinity increases across the

landscape, plant associations tend to shift. This

gradient of associations proceeds from lower to higher

salinity as follows: (1) big sagebrush; (2) spiny

hopsage (Grayia spinosa), rabbitbrush

(Chrysothamnus spp.), horsebrush (Tetradymia spp.);

(3) winterfat; (4) shadscale; (5) greasewood

(Sarcobatus vermiculatus), red sage (Kochia

americana), Nutall’s saltbush (Atriplex nuttallii); (6)

seablite (Suaeda spp.), saltgrass (Distichlis stricta),

saltwort (Salicornia spp.), Allenrolfea spp. (Gates et al.

1956, Flowers and Evans 1966).

Descriptions of the plant associations within this

ecosystem provide less detail than do descriptions of

the sagebrush ecosystem. West (1983b) splits the

ecosystem into two major subdivisions based on

subsurface water within or remaining below the upper

1 m (3 ft) of the soil. Lowland habitats are typically

found near the central playa of enclosed basins. The

water table is occasionally present at the surface and

remains within the upper 1 m (3 ft). Vegetation in this

region is therefore dominated by those halophytes,

such as greasewood (Sarcobatus vermiculatus), some

low-growing half-shrubs (Allenrolfea occidentalis and

Salicornia utahensis), and saltgrass (Distichlis stricta),

that can tolerate occasional anaerobic conditions in the

root zone . Descriptions of plant communities with

some quantitative information are available for northern

Utah (Fautin 1946, Flowers and Evans 1966). These

communities are not a major problem for the BLM in

the Great Basin and therefore are not included in the

remaining discussion of the problem analysis.

Upland habitats are characterized by the water table

remaining below a 1 m (3 ft) depth. Shadscale (Atriplex

confertifolia) is the principal upland shrub and dominates upland habitats. Shadscale is a complex

species consisting of several polyploid races. Diploid

races are generally found in upland habitats at elevations above the upper levels of the Pleistocene lakes

11
whereas polyploids are associated with valley bottoms

throughout the Great Basin (Stutz and Sanderson

1983). After the recession of the Pleistocene lakes,

shadscale appears to have expanded its range from

two geographical regions: (1) from the lee side of the

Sierra Nevada Range and (2) from the Colorado

Plateau (Sanderson et al. 1990). As it expanded its

range, distinct morphological and chemical differences

evolved. In general, diploid populations are found on

mesic sites whereas polyploid populations are associated with either drier or more alkaline sites (Sanderson

et al. 1989).

Shadscale communities contain one or more associated species. Associated shrubs include winterfat, bud

sage (Artemisia spinescens), spiny hopsage, and

Mormon tea (Ephedra nevadensis). Canopy coverage

averages from 0.5 to 2% with maximum values of 6%

(Fautin 1946). The perennial herbaceous component

is represented by grasses such as basin wildrye

(Elymus cinereus), Indian ricegrass (Oryzopsis

hymenoides), and squirreltail (Sitanion hystrix) in the

northern portions of the Great Basin (Franklin and

Dyrness 1973). Further south, summer precipitation

occurs with greater regularity causing a shift to Indian

ricegrass and galleta grass (Hilaria jamesii) (Fautin

4946, Billings 1951, West and lbrahim 1968). Native

forbs are a minor component in shadscale communities and are largely represented by globemallow

(Sphaeralcea spp.) .

Winterfat communities occur throughout the Great

Basin and appear as localized ‘islands’ within

shadscale communities (Fautin 1946). Winter-fat

communities differ from shadscale communities mainly

because winterfat communities lack shadscale.

Billings (1945) speculated that winterfat dominates in

areas where shadscale has died, but additional support

for this hypothesis does not exist.

Regardless of the specific vegetation association, plant

coverage in upland communities averages about 7 to

8% with interspaces between plants occupied by

mycrophytic crusts and rocks (Billings 1949, 1951,

Fautin 1946, West and lbrahim 1968, West 1983b).

These crusts are composed of free-living, nitrogenfixing bacteria, lichens and blue-green algae which

enhance soil stability, improve water infiltration, provide

pulses of available nitrogen, and enhance seedling

establishment (Loope and Gifford 1972, Rychert and

Skujins 1974, Kleiner and Harper 1977, St. Clair et al.

1984). Although chenopods are non-mycorrhizal

plants (Allen 1988) these microphytic crusts appear to

fill a niche similar to the niche VAM fills in sagebrush

ecosystems.

Exotic weedy species are as

ecosystem as they are in the

12

much a component of this

sagebrush ecosystem.

Cheatgrass has been noted as a component in the

upland salt-desert shrub since before the 1940s

(Fautin 1946). Some areas have experienced shifts

from shadscale dominance to cheatgrass (Sparks et al.

1990). Although cheatgrass is present, it is not the fire

risk in salt desert shrub communities that it is in shrubsteppe communities because it does not normally

produce sufficient fuel to carry wildfires (West 1983b).

Currently, medusahead and the knapweeds are not

found on these sites, but their ranges may not have

reached their maximum. Two chenopod annuals,

Russian thistle (Salsola and halogeton (Halogeton

glomerata), are found on sites of severe soil disturbance. These annuals were a major problem in Utah

and Nevada with severe overgrazing before the 1950s.

The reduction of livestock numbers and a shift in

grazing season resulted in a decline in the impact of

chenopod exotics (West 1983b).

It is relatively common for shrubs in this ecosystem to

experience cycles of mortality (Nelson et al. 1989,

Pyke and Dobrowolski 1989). Successful restoration

of native plants within this ecosystem depends largely

on adequate precipitation during germination and

establishment. Natural reseeding via a residual

seedbank may provide the greatest success. If

seedbanks no longer exist, then technologies for

successful restoration are limited (see papers in

Tiedemann et al. 1983). Basic demographic research

concerning reproduction, seedbanks, seed germination

conditions and seedling survival conditions is needed

for the dominant shrubs, forbs and grasses of this

ecosystem. This research should also identify the

impact of livestock and wildlife on these demographic

parameters.

Il. Vegetation

Dynamics of Semiarid

Communities

Forecasts of the likelihood that a site will successfully

recover after a disturbance are based on models of

vegetation dynamics for similar sites. Much of our

current basis for judging rangeland dynamics is based

on the theory that successional trajectory will lead to a

single plant community provided that severe disturbances are eliminated. This single plant community is

commonly called a climatic climax or a potential natural

community. This view of rangeland condition is based

on Clements’ idea that communities pass through a

succession of intermediate communities before

attaining a stable community, the climatic climax.

These ideas are widely taught and are presented in
current textbooks of rangeland management (e.g.,

Stoddart et al. 1975, Heady 1975, Holechek et al.

1989). The traditional rangeland dynamics model used

in determining condition classes in the United States

were developed by Dyksterhuis (1949, 1958) became

accepted by federal land management agencies in the

late 1960s (e.g., USDA 1969) and were included in

Stoddart, Smith and Boxs’ (1975) range management

text.

This successional approach for defining rangeland

condition classes was strongly criticized because it did

not accurately reflect the health of grazed rangeland.

For example, the species composition of herbaceous

plants in communities dominated by woody plants

tends to decline in the understory as woody species

dominate the site. As woody plants become dense the

elimination of livestock grazing will not be sufficient to

allow the herbaceous plants to recover. On some

sites, woody plants replace herbaceous plants regardless of the livestock grazing because suppression of

fires allows the more competitive woody species to

dominate. Because of several problems associated

with inaccurate condition classes formulated from the

traditional rangeland succession model, the Rangeland

Inventory Standardization Committee (1983) recommended using the potential natural community (PNC)

concept of comparing the current vegetation to the

potential community the site can accommodate while

considering past modifications of the site. Under the

PNC approach, managers recognize that a site may

develop into one of many potential communities

depending upon the type and severity of the disturbance on the site. Yet, the PNC approach largely

recognizes a single steady state that the community

will achieve if disturbances are eliminated. Intermediate stages are recognized as successional stages that

develop from early-seral to mid-seral to late-seral

communities after disturbances are eliminated or

reduced. This approach is currently being used by

several federal agencies including the BLM to describe

rangeland condition.

Regardless of the traditional condition class approach

chosen, both are strongly rooted in the Clementsian

theory that succession is a predictable linear bidirectional process. Succession progresses towards a

climax or potential community if disturbances are

eliminated and regresses from the climax or potential

community if disturbances continue. These two ideas

have largely been accepted for rangeland management because of the desire to find a single objective

standard for comparing the impacts of grazing animals

on each vegetation community (Smith 1988).

Alternative theories of vegetation dynamics take an

individual species approach to the development of

communities based on the early work of Gleason

(1926). These alternatives rely on the species’ lifehistory and on the interactions among the individuals

that constitute the population and between the individual and its environment (Connell and Slatyer 1977,

White 1979, Noble and Slatyer 1980, Westoby 1980,

Huston and Smith 1987, Westoby et al. 1989). Under

these theories, disturbance becomes a part of the

ecosystem and several stable communities have the

potential to develop after disturbances are eliminated

or reduced. The nature, frequency, and intensity of the

disturbance differentially impact each plant species,

therefore the community formed after a disturbance

may depend on the abilities of the species to survive

the disturbance or to replace themselves through

reproduction after the disturbance. The likelihood of a

species surviving or replacing itself after a disturbance

depends on the species germination characteristics,

competitive ability, growth, phenology, and on its

genetic variability and plasticity related to the myriad of

environmental factors it may face. In short, forecasting

the dynamics of a community following a disturbance

requires the knowledge of the physiological and

demographic responses of the individuals that constitute the interacting populations of species that form

that community.

The individualistic approach to vegetation dynamics

recognizes that more than one potential community

can result following a disturbance. Acceptance of this

idea has led to the recognition that multiple stable

states or communities may exist for any given site

(Holling 1973, May 1977, Walker et al. 1981). In a

recent review of rangeland successional models,

Westoby et al. (1989) outlined the limitations and

exceptions to the traditional approach that lead them to

advocate that many stable plant communities have the

potential to exist on any given landscape. They have

proposed an alternative state-and-transition model for

describing rangelands and for applying management

prescriptions. States are relatively stable assemblages

of species that develop on a site depending on the

timing, intensity and severity of disturbances. Transitions, also referred to as thresholds (c.f., Friedel 1991),

are actions that result in new states (communities) of

species assemblages. Transitions are characterized

by the following: (1) unpredictable natural events, such

as fires or changing climatic conditions, or humaninduced uses of the ecosystem, such as farming or

grazing; and (2) the change in states is not reversible

on a practicable management time scale without

human intervention (e.g., artificial restoration).

We believe that the state-and-transition model is more

appropriate for restoration and maintenance of semiarid communities of the Great Basin and ColumbiaSnake River Plateau. This approach has been suc13
cessfully applied to arid and semiarid rangelands

where the interaction between different types of

disturbance and climate can lead to alternative stable

plant communities. Within the Great Basin and

Columbia-Snake River Plateaus, Laycock (1991)

proposed a state-and-transition model for the sagebrush-steppe ecosystem that combines transitions

resulting from grazing, fire, and climatic conditions that

result in the development of six relatively stable

communities (Fig. 2). Refinement of such a sagebrush-steppe model should be incorporated into some

of the long-term monitoring of undisturbed and disturbed communities within the Great Basin and Columbia Plateau. Analysis of plant community data should

incorporate ordination techniques to document when

communities have transcended between vegetation

STATE-AND-TRANSITION MODEL FOR A SAGEBRUSH

GRASS ECOSYSTEM

I

111 I/

Figure 2. State-and-transition diagram for sagebrush-grass vegetation. An arrow represents the transition (T) between stable states.

Transitions between stable states in the absence of annuals as

dominants:

T 1 - Heavy continued grazing. Rainfall conducive for sagebrush

seedlings.

T2 - Difficult threshold to cross. Transitions usually will go through

T3 and T5.

T3 - Fire kills sagebrush. Biological agents such as insects, disease or continued heavy browsing of the sagebrush by ungulates could have the same effect over a longer period of time.

Perennial herbaceous species regain vigor.

T 4 - Uncontrolled heavy grazing favors sagebrush and reduces

perennial herbaceous vigor.

T 5 - Light grazing allows herbaceous perennials to compete with

sagebrush and to increase.

If climate is favorable for annuals such as cheatgrass, the following

transitions may occur:

T 6 - Continued heavy grazing favors annual grasses which replace

perennials.

T7 - Difficult threshold to cross. Highly unlikely if annuals are

adapted to area.

T8 - Burning removes adult sagebrush plants. Sagebrush in seed

bank.

T 9 - In absence of repeated fires, sagebrush seedlings mature and

again dominate community.

T 10 - Repeated burns kill sagebrush seedlings and remove seed

source.

T 11 - Difficult threshold to cross if large areas affected. Requires

sagebrush seed source.

T12 - Intervention by man in form of seeding of adapted perennials.

states and to determine when significant management

efforts are required to return a community to a previous

state (Friedel 1991). For salt-desert shrub ecosystems, similar models need to be developed to provide

managers with a more accurate method of predicting

the impact of disturbances on salt-desert shrub communities.

Ill. Competition and

Establishment

A. Factors in Competition

According to Nowak and Anderson (manuscript in

preparation), aboveground productivity of sagebrushsteppe vegetation in the Great Basin is thought to be

limited first by water and then by nitrogen. They also

state that the agents of stress in arid and semiarid

ecosystems in western North America are likely to

disrupt water and nutrient cycles with a resulting impact

on plant interactions. Plant densities, relative competitive abilities, site adaptation, and proper seeding

techniques must also be considered as factors contributing to plant interactions.

Water

Plant competition for soil water generally is extreme in

arid regions. A dense stand of annual vegetation such

as cheatgrass (Bromus tectorum), halogeton (Halogeton glomeratus) or Russian thistle (Salsola kali) may

compete so intensely with seeded or transplanted

perennial species as to inhibit their establishment or

reduce their vigor sufficiently to limit survival and

growth. Whenever surface disturbance occurs, the

invasion of annual species is especially acute. Thus,

any manipulation of the vegetation or soil surface that

increases water accumulation and retention for beneficial use by specific desirable plants would be advantageous (Van Epps and McKell 1983).

Nutrient Levels

McLendon and Redente (1991) discussed the roles of

nutrient availability and mineralization as external

factors in dominance and succession on disturbed

sites. Results of their study suggested that dominance

of a site by annuals in early phases following soil

disturbance is related to high nutrient availability.

Several studies were cited to provide the following

rationale: The higher potential growth rates of early1 4

I Open stand of

sagebrush with

productive

herbaceous

perennial understory

T1

T2

II Dense sagebrush cover.

Depleted perennial herbaceous

understory with

sagebrush

seedlings present

T6

T7

IV Dense sage- brush cover. Abundant annuals,

few herbaceous

perennials, and

sagebrush seedlings present

T12

 T5 T3

 T4

 T9 T8

III Recently burned peren- nial herbaceous

species and

sagebrush

seedlings

VI Repeated

burns. Only annuals with no

perennial herbaceous species

or sagebrush

present

T10

T11

V Recently

burned. Dominated by annuals

with sagebrush

seedlings present

T12

 T12

 (After Westoby, Walker and Noy-Meir, 1989)
successional annuals might allow them to outperform

the slower-growing perennials as long as resources

are relatively abundant. However, as resources

become more limiting, species with lower nutrient

requirements (per unit biomass) should have the

advantage. Dominance of disturbed nutrient-rich sites

by annuals may be a function of two major factors:

seed availability and rapid potential growth rate. The

relatively high levels of available resources often

characteristic of initial conditions in secondary succession allow the potentially high growth rate of earlysuccessional annuals to be expressed. High growth

rates under such conditions result in high biomass

production, a rapid incorporation of nutrients, and a

reduction in their corresponding levels in the available

nutrient pool. If the decomposition rate lagged behind

this uptake rate, a temporary deficiency would occur.

Such a deficiency could reduce the growth of annuals

sufficiently to allow for an increase in growth by less

nutrient-demanding perennials. McLendon and

Redente (1991) concluded that an ample supply of

nitrogen (N) is the key factor in the ability of annuals to

achieve and maintain dominance on recently disturbed

sites, even in semiarid ecosystems. Their results

suggested: 1) since important keys to understanding

plant succession dynamics lie specifically in N availability, then, by implication, the processes of decomposition and mineralization appear to be important

successional factors; and 2) general successional

processes hold true for semiarid as well as for mesic

systems.

The unpredictability of climate in the region results in

some years when resources are high so that competitive plants are favored. However, in years when

resources are limited, such as during droughts, plants

that are stress tolerant are often favored (see review by

Pyke and Archer 1991). Plants chosen for restoration

need to combine characteristics of both competitiveness and stress tolerance.

Providing a mixture of species in a community is one

approach to reducing the impact of unpredictable

climatic events. Field experiments often indicate that

multiple resources may limit plant growth (Lauenroth et

al. 1978, Chapin and Shaver 1985). High diversity

communities can maximize resource utilization not only

across a heterogenous landscape, but also over time

(McNaughton 1977, Chapin and Shaver 1985, Collins

et al. 1987).

Plant Density

Intensity and effects of competition are accentuated at

higher plant densities. Excessive seeding rates may

have no significant benefit on total stand productivity,

but may produce a density-induced reduction in

individual plant biomass. Innate competitive ability is

influenced by density effects. Samuel and DePuit

(1987) reported that perennial grasses responded

differently in competition. Species with higher innate

competitive ability increased in abundance in response

to seeding rate. Species with lower inherent competitive ability were eventually retarded by more responsive species as seeding rates and hence plant densities increased. This density-dependent increase in

competitive exclusion was reflected in the decline of

seeded grass diversity as seeding rates increased.

Overly heavy seeding rates should be avoided in

situations where mixed stands are desired.

Another approach to reducing negative effects of high

density on establishment involves increasing the

distance between a plant and its nearest competitor.

Removal of competing vegetation can be accomplished by mechanical means, herbicides, prescribed

burning, grazing, etc. Proximity of competing species

may be reduced by planting seeds of different species

into different microsites, rows, etc.

Relative Competitive Abilities

Innate differences in competitive ability among species

may strongly influence competitive interactions and,

therefore, establishment among species in mixtures.

Relative competitive abilities of plants may be related

to seed size, relative ease and rapidity of germination,

seedling vigor, production potential, and/or site (environmental) adaptation. Competitive ability among

species should be considered when mixtures of

seeded species are composed. Seed mixtures that

contain competitively superior species often produce

stands in which composition is not related to the seed

composition (DePuit and Coenenberg 1979, Schuman

et al. 1982, Redente et al. 1984). Consideration should

also be given to nonseeded species which may

potentially be important competitors. Properly applied

seeding methods and other cultural practices may

sometimes compensate for interspecific differences

when attempting to establish species with differing

competitive and/or germination attributes. Seeding

less competitive species first, allowing sufficient time

for establishment, and later interseeding more competitive species may be a method of overcoming differences in seedling vigor (Coenenberg 1982).

Competitive abilities can be quantified using species

mixture experiments similar to those presented by Law

and Watkinson (1987). These experiments should be

conducted at field locations so that density-dependent

and density-independent effects could be determined.

1 5
Steve Monsen (personal communication) has observed that attempting to transplant native shrub

seedlings into established crested wheatgrass has

often failed. Transplanting native shrub seedlings into

stands of established native grasses may have a better

chance of success because native grasses generally

have coexisted with native shrubs and are thus less

competitive with them.

Harris (1977) discussed root phenology as a factor of

competition among grass seedlings. He compared

root phenology characteristics of cheatgrass,

medusahead and bluebunch wheatgrass seedlings.

Root phenology characteristics of cheatgrass and

medusahead seedlings enable them to out-compete

seedlings of bluebunch wheatgrass. Seeds of annual

grasses germinate earlier in the fall, under drier and

colder conditions than do bluebunch wheatgrass.

Once germinated, roots of the annuals grow faster, not

only under conditions of favorable fall temperature and

moisture, but at near-freezing soil temperatures typical

of winter in the northwest which includes the northern

Great Basin and Columbia Plateau regions. The

annuals also increase their number and length of roots

during winter so that by spring they are in control of the

site. Annual grasses exhaust upper profile available

moisture supplies to depths beyond the reach of

developing bluebunch wheatgrass roots. Consequently, bluebunch wheatgrass seedlings succumb to

drought, under these conditions, before producing

seeds. The annuals also die, but not before reproduction. If a bluebunch wheatgrass seedling does survive

the summer, its root phenology pattern changes to

include a period of summer dormancy, which provides

a competitive advantage over annuals. Successful

establishment of bluebunch wheatgrass requires

control of annuals.

Harris and Wilson (1970) compared root elongation at

low temperature among cheatgrass, medusahead,

bluebunch wheatgrass and crested wheatgrass.

Rapidly elongating cheatgrass and medusahead roots

penetrated the soil ahead of bluebunch wheatgrass

and used available moisture. Results were similar to

those found by Harris (1967) comparing cheatgrass

and bluebunch wheatgrass. In contrast, crested

wheatgrass roots penetrated the soil almost as rapidly

as the two annual grasses and remained in favorable

moisture (Harris and Wilson 1970). The differences in

root penetration resulted in lower leaf water potentials

and poorer survival in bluebunch wheatgrass than in

crested wheatgrass. Results suggested that in areas

where root growth occurs at low temperatures and

where lands are infested with cheatgrass and

medusahead (e.g. Great Basin and Columbia Plateau),

seedlings of a plant such as crested wheatgrass would

be more successful than seedlings of a plant such as

bluebunch wheatgrass.

Medusahead germinates and grows earlier than

cheatgrass and its root anatomy adapts it for a later

phenology. Medusahead is also adapted to higher

temperatures, as indicated by germination and root

growth reactions. Harris (1977) demonstrated that

medusahead germinates significantly faster and more

completely than cheatgrass under conditions of

relatively low water potentials (-0.5 to -1.O MPa) and

variable temperatures (10 to 30°C). Medusahead roots

have a larger diameter than cheatgrass roots and

medusahead cell walls are thicker than those of

cheatgrass. Cheatgrass senesces earlier than

medusahead because its root system is poorly protected against droughty soils. The endodermal layer is

thin and the root poorly adapted to translocate water

through the dry, hot upper soil layer in summer conditions (Harris 1977). Medusahead primary and adventitious root phenology is comparable with or earlier than

that of cheatgrass, so medusahead seedlings compete

successfully with cheatgrass seedlings (Harris 1977).

Hironaka (1961, oral presentation at Symposium:

Ecology, management and restoration of intermountain

annual rangelands, Boise, ID, May 1992) has suggested that later maturation by medusahead restricts it

to the 10-inch and above precipitation zones of the

cheatgrass type and below 5000 feet in the northern

Great Basin. According to Hironaka (1961),

medusahead requires residual soil moisture following

cheatgrass maturation to be able to complete its

growth. However, root morphology differences noted

by Harris (1977) suggest that medusahead may be

able to extract needed soil moisture to a lower water

potential than cheatgrass and perhaps may not be

restricted to wetter sites (i.e. greater than 10 inches

annual precipitation).

Evans et al. (1970) and Evans and Young (1977) have

stated that on cheatgrass dominated sites, virtually no

perennial grasses would be established without weed

control. During average or above-average precipitation

years, initial precipitation is sufficient to provide available seedbed moisture, but with annual weed growth

this moisture is soon exhausted and becomes unavailable to perennial grass seedlings. Goebel et al. (1988)

stated that even the relatively competitive ‘Secar’

bluebunch wheatgrass (Agropyron [Pseudoroegneria]

spicatum) will not establish when in competition with

medusahead without control of medusahead (and

other annuals).

1 6
Adapted Species and

Proper Techniques

Haferkamp and Miller (1988) concluded that reseeding

rangelands has a high risk, and even though projects

are designed and conducted utilizing the best available

methods of seedbed preparation and planting, failures

can occur when the environmental stress (i.e. dry soil)

is too great. The potential for success can be enhanced by paying particular attention to site selection,

selecting adapted species with good seedling vigor,

preparing a firm weed-free seedbed, and planting at

the proper season with the proper equipment.

Van Epps and McKell (1983) concluded that intense

plant competition from weedy annual species has a

negative influence on the survival and growth of

perennial plant species transplanted either as bare-root

or container-grown stock. Plant species most likely to

survive are those which can endure competition from

annual plants. Effects of reduction of competition are

generally reflected in greater plant height and cover.

Plant species most likely to withstand competition are

those best adapted to a site. Species poorly adapted

to a site apparently are not able to respond to the

improved control of competition. Improved establishment of site adapted plants in arid sites appears to be

possible by controlling competition of annual weedy

forbs and grasses for a period of one or two years.

Three or more growing seasons may be needed to

evaluate the permanent establishment of plants under

arid conditions. Plants under uncontrolled competition

appear to stabilize their survival rate by the end of the

third year. Springfield (1970) reported that survival of

fourwing saltbush transplants, in the Southwest under

no competition, stabilized during the fourth year

following field planting, while the survival rate of those

growing in competition with grass was still declining in

the fifth year.

There are large variations among species as to the

negative impact of plant competition on plant survival

and growth. Prostrate summer cypress (Kochia

prostrata), an exotic perennial, was noticeably more

successful in its establishment success than fourwing

saltbush, winterfat, or Russian wildrye in studies

conducted by Van Epps and McKell(1983). We

suspect that variation in competitive ability exists in

native species as well.

Plant establishment is governed not only by seed and

seedling autecology, but by synecological interactions

among plants during the establishment phase (Samuel

and DePuit 1987). Competition during the seedling

stage can strongly influence plant establishment. The

nature of this influence is governed by an interacting

array of plant related and external factors. Success in

range seeding depends in part upon proper understanding of the effects of competition during the

establishment phase and the factors that modify this

phenomenon. Competition and its influence can be

manipulated by appropriate modification of both plant

related and external factors.

B. Climate Change and

Competition

Ozone Depletion

According to Caldwell et al. (1989), ozone depletion

and the resulting increase in solar UV-B radiation may

have numerous consequences including photochemical, tissue, whole plant and community effects, most of

which are not at all well understood. Although many of

these factors could potentially be affected by increased

UV-B radiation, field studies are rarely able to detect

effects because field conditions appear to buffer these

effects (Caldwell et al. 1989). Therefore, ozonedepletion and UV-B radiation increase is not likely to

have a major impact on rangeland ecosystems.

CO2 Enrichment

Results of experiments by Zangerl and Bazzaz (1984)

suggested that CO2, enrichment can significantly affect

plant communities. The effects were most consistent

for whole community attributes, less so for groups of

species and still less for individual species. Overall

community production increased with CO2, enrichment

C3 species increased in dominance relative to C4

species, often, but not always, independent of light and

nutrient availability. At the individual species level

resutts were much more varied and often depended

upon the availability of resources other than CO2. The

authors found that CO2 enrichment affected vegetative

biomass production differently from seed biomass

production, that the relative allocation of resources to

seed vs. leaves and stems was affected, and that,

contrary to expectation, individual C4 species could

benefit from CO2 enrichment. The authors postulated

that relative success of species in a community will be

affected by shifts in availability of CO2. However, later

successional communities where species compete less

with one another may be less affected than earlier

successional communities where many species have

broad niche overlap. Also, species of later successional communities have greater leaf resistances and

may be expected to be less sensitive to an increase in

CO2, but this is not the case for the sagebrush steppe

where the dominant perennial species have high

17
conductances, high photosynthetic rates and would be

expected to respond to high CO, concentrations (e.g.

Caldwell et al. 1977, Caldwell et al. 1981).

Mayeux et al. (1991) have hypothesized that favorable

effects of increasing CO, that apply to all functional

groups of plants, especially improved water use

efficiency and amelioration of stress, suggest that

overall productivity of rangelands will increase. However, increased productivity will probably continue to be

reflected in increased biomass of less desirable C3

weeds and woody vegetation, as opposed to C4 warmseason perennial grasses, where the two functional

groups occur together. It also seems reasonable to

expect improved productivity of C3 cool-season

grasses, and to consider whether increasing atmospheric CO2 is influencing ecosystem structure and

function in environments where they predominate.

Citing several other sources, Mayeux et al. (1991)

stated that woody plants respond to elevated CO2 to

the same or greater extent as C3 herbs. There is a

need for research to examine the role of elevated CO2

to favor components of the ecosystem to such a

degree that management must be concerned about

shifts in species composition.

Greenhouse Effect (Global Warming)

Most general circulation models of global warming

predict warmer temperatures and midcontinental drying

(Office for Interdisciplinary Earth Studies/UCAR 1991).

One of the research priorities identified by the workshop on Arid Ecosystems interactions (Office for

Interdisciplinary Earth Studies/UCAR 1991) was to

conduct fundamental research into physiology and

growth of vegetation in arid and semiarid regions and

its response to the changing climate. Studies of

vegetation response should include both field experiments and modeling. Experiments should be designed

to preview effects of environmental changes and in

temperature and precipitation and to provide rigorous

tests of process models.

C. Controlling Competition

Undesirable plants and noxious weeds occupy many

range sites and their populations are increasing

dramatically. In some cases noxious weeds have also

invaded and become established on sites considered

to be in “Excellent” condition and on Wilderness Study

Areas. Control of undesirable plants, including noxious

weeds, is necessary to stop their spread and to

facilitate restoration of impacted sites with native

species.

Physiological stage of growth is a primary factor

determining effective treatment periods for control of

problem plants. Since an annual completes its life

cycle in one year, reproduction of annuals is dependent on seed production with few exceptions. Thus,

most control programs for annuals are aimed at the

prevention of seed production. This is accomplished

by killing the plants prior to or during early flowering.

Preventing seed production is often an important

consideration with perennial plants also, but may not

be ultimately successful in controlling the undesirable.

Methods that completely remove plants from the soil,

such as grubbing or removal by power equipment,

effectively kill most plants at any stage of growth

(Vallentine 1989).

Perennial plant control methods that are based on the

removal of top growth (e.g. cutting, mowing, grazing, or

chemical defoliation) are normally most effective when

the plant’s food reserves and ability to produce regrowth are at their lowest point (Vallentine 1989) and

may require multiple applications for successful control.

In addition to the listed official noxious weeds of the

states included in the project area, plant species

considered to be of concern and in potential need of

control in selected situations include: sagebrush,

juniper, cheatgrass, medusahead, and the knapweeds.

Sagebrush

In areas of high sagebrush cover, there is essentially

no way to reestablish native, or introduced, herbaceous cover without first removing some of the dense

sagebrush canopy (Winward 1991). Reestablishment

of a more natural ecological balance in the overstory/

understory in most sagebrush ecosystems will require

a much greater effort at restoring some of the natural

mosaic of sagebrush canopies that is thought to have

existed prior to European settlement of the west. To

accomplish this, a long-term program will be needed

that will allow periodic, patterned removal or thinning of

sagebrush.

Juniper

The June 1991 BLM Western Juniper Working Group

report to the Oregon/Washington Management Team

on expansion of western juniper in eastern Oregon

stated that western juniper is expanding over vast

areas of BLM rangelands in eastern Oregon at an

alarming rate and the area of total juniper domination is

rapidly becoming larger. A projected result is an

inability to meet the land use objectives of maintaining

or improving ecological status, improving biological

diversity and maintaining or improving wildlife habitat

1 8
and watershed stability. Degradation of water quality,

loss of productivity, increased erosion, and nutrient tieup are also listed as problems resulting from juniper

encroachment. Fire is believed to have played a major

role in regulating the amount of juniper in the eastern

Oregon area. Fire or some other intervention is

necessary to inhibit juniper encroachment. The most

effective control can be achieved by intervention in

areas of encroachment while the trees are four feet tall

or less, at which stage they are more susceptible to

control and they have probably not yet severely

suppressed understory vegetation.

Cheatgrass

Much of the sagebrush-steppe of western North

America has been converted to an annual grassland

dominated by introduced species (Whisenant 1990).

Cheatgrass is the dominant species on more than 100

million ac (40 million ha) of the Intermountain West

(Mack 1981). The sagebrush-steppe of Idaho’s Snake

River Plains probably evolved with fire-return intervals

of 35 to 100 years (Whisenant 1990). With the introduction of cheatgrass and domestic livestock, the firereturn interval decreased to between 2 and 4 years on

many sites. This has converted millions of acres from

sagebrush-steppe to annual grasslands dominated by

introduced species. Species richness dramatically

decreased at several spatial scales of resolution as

these fires became larger, more uniform, and more

frequent (Whisenant 1990). Revegetation efforts on

these areas will be largely ineffective until fire sizes

and fire frequencies are greatly reduced. Therefore,

collaboration is necessary with the Intermountain

Greenstripping and Rehabilitation Research Project

(IGRRP) since the main focus of IGRRP is to reduce

the size and frequency of fires (Pellant 1990).

Noxious Weeds

“Noxious Weed” means any weed designated by a

state that is injurious to public health, agriculture,

recreation, wildlife, or any public or private property.

Noxious weeds have become so thoroughly established and are spreading so rapidly on state, county,

and federally-owned lands, as well as on private land,

that they have been declared by state laws (e.g. ORS

570.505 in Oregon) to be a menace to the public

welfare. Steps leading to eradication, where possible,

are necessary. It is further recognized that the responsibility for such eradication and/or intensive control

rests not only on the private landowner and operator,

but also on the county, state, and federal governments.

Weeds designated as noxious are listed by state in

Appendix F.

Plant Control by Fire

Several undesirable plants are selectively controlled by

burning when the combination of plant growth stages

and environmental factors including soil moisture is

ideal. However, repeated burning can seriously

deplete root reserves of desirable perennials and even

cause their death, particularly in semiarid areas.

Season of burning and phenological stage of growth

directly affect plant response to burning, with each

plant species responding somewhat differently

(Daubenmire 1968, Wright et al. 1979, Vallentine

1989).

Vallentine (1989) summarized the plant and environmental factors known to affect the tolerance, resistance, or avoidance of damage to plants exposed to

fire.

Plant factors reducing fire damage

Sprouting ability

Rhizomes deep in soil

Fibrous roots deep

Growing points at or below ground level

Tolerant of herbage removal

High storage CHO reserves

Bark thick (with ground fire)

Foliage elevated (with ground fire)

Plants dormant

Low accumulation of tuft

Environmental factors reducing

fire damage

Low ground debris level

High moisture content in plant base and

mulch

Moist soil (good vigor plants)

Short-duration fire (moves rapidly)

Prior herbage removal

Vigor not reduced by prior insect,

disease, mechanical, or

chemical damage

Plant factors increasing fire damage

Nonsprouting

Rhizomes absent or shallow or stolons only

Fibrous roots shallow or above mineral soil

Growing points above ground level or elevated

Intolerant of herbage removal

Low storage CHO reserves

Bark thin (with ground fire)

Low foliage (reached by ground fire)

Plants actively growing

High basal leafage accumulation

Environmental factors increasing

fire damage

High ground debris level

Low moisture content in plant base and mulch

Dry soil (low vigor plants)

Long-duration fire

Ungrazed (i.e., added fine fuel)

Vigor reduced by prior treatment

Damage by fire to desirable herbaceous plants in the

sagebrush zone is fairly low, with the exception of

Idaho fescue. Idaho fescue, in contrast to bluebunch

~

wheatgrass, is very leafy and compacted at the base,

where dead material accumulates as fuel (Vallentine

1989). The high density of material at the base of the

plant results in higher temperature and increases the

probability of the plant’s death when burned. Many

palatable shrubs such as sagebrush, curlleaf mountain

mahogany, cliff rose, and bitterbrush are susceptible to

damage by fire.

Repeated burning, or burning in late summer, strongly

favors cheatgrass when cheatgrass is present in the

interspaces among native perennials. If cheatgrass

rapidly stabilizes at high densities following burning,

the site will be mostly closed to seedlings of perennial

19
grasses (Young and Evans 1978). This has resulted in

a conversion to nearly pure stands of cheatgrass

(Bunting et al. 1987). Cheatgrass is often abundant in

stands of Wyoming big sagebrush that have sparse

understories of native species in western Idaho,

northern Nevada, and eastern Oregon. Burning these

communities will remove brush, but it will not provide

more perennial grass where cheatgrass has become

dominant. The annual grass stage is relatively stable

with bottlebrush squirreltail (Sitanion hystrix) being the

primary perennial grass to increase on the more arid

sites. Once an area burns and becomes dominated by

cheatgrass, the risk of wildfire becomes much greater

(Hironaka et al. 1983) and the likelihood of conversion

back to perennial grasses by natural regeneration is

greatly diminished (Bunting et al. 1987). Where

cheatgrass is more than half of the understory of the

area or the area cannot be protected against subsequent accidental burns, big sagebrush sites should not

be burned (Pechanec and Stewart 1954).

Annuals such as cheatgrass (Bromus tectorum) are

very tolerant to fire because the seed is resistant to

fire. Moreover, cheatgrass burns in June or July after

seed dispersal and death of the adult, but leafy perennials that are still actively growing can be killed. Thus,

frequent fires in early to mid summer will promote

cheatgrass. Medusahead has a seedhead moisture

content above 30% for approximately a month after the

leaves and stems begin to dry and provide a sufficient

volume of fuel to carry a fire. While the seed moisture

content is still high (soft dough stage), medusahead

seed is readily killed by high temperatures. Burns at

this stage of growth are recommended in the afternoon

when burning slowly into a mild wind to achieve

sufficient heat (McKell et al. 1962). Medusahead seed

is not viable until awns begin to curl. Burning after

medusahead seeds shatter and fall to the ground is

ineffective (Vallentine 1989). If too few perennial

grasses are in the understory of sagebrush-annual

grass communities, major renovation, including

seeding, will be needed to restore a community to a

sagebrush-perennial grassland.

Burning has been an effective, economic control of

nonsprouting juniper where a uniform burn has been

obtained (Vallentine 1989). Broadcast burning of live

juniper trees requires a dense stand of trees (400 or

more per acre) or a flammable understory to be

effective (Arnold et al. 1964). Burns in pinyon-juniper

have often burned clean on flat or gently rolling terrain

but have left islands of unburned trees on hills and

ridges where the junipers grow in a thin stand with few

understory plants. Large juniper trees often provide

their own firebreak zone through intensive competition,

and grazing further removes the flammable understory.

Grasslands being invaded by junipers can be broadcast burned to control the junipers before the herbaceous understory is reduced to the degree it will not

carry a uniform burn, however, caution must be used if

fire-intolerant shrubs and herbaceous plants are also

found in the stand. Nonsprouting juniper seedlings and

saplings are readily killed under these conditions, and

even sprouting junipers may be materially suppressed

(Vallentine 1989). Following intense wildfires in the

pinyon-juniper type in central Utah, big sagebrush

often became dominant by 11 years later, with juniper

beginning to appear shortly thereafter (Barney and

Fischknecht 1974). Juniper often became prominent

after about 46 years and dominant at about 70 years.

Once dominant, broadcast burning becomes difficult

except under hazardous dry, hot, and windy conditions.

Wyoming big sagebrush occurs on the most arid areas

within the range of big sagebrush. Annual precipitation

may average less than 7 inches in some communities

(Hironaka et al. 1983). Low productivity and a resultant

lack of fine fuels of these areas often make prescribed

burning difficult (Schmisseur and Miller 1985, Bunting

et al. 1987). Wyoming big sagebrush cover seldom

exceeds 25%, which contributes to the difficulty in

getting a fire to carry through such communities. If the

canopy cover criterion is satisfied, it is important to

have at least 250 pounds of fine fuel per acre to carry

the fire. Low sagebrush areas are not likely candidates

for prescribed fire because fire will not easily move

through low sagebrush (Schmisseur and Miller 1985).

Wright (1985) discussed the effects of fire on grasses

and forbs in sagebrush-grass communities. Effect of

fire on grasses is largely determined by season of

burn, size of plant, amount of dead material, growth

form, species, precipitation, and whether it is an annual

or perennial. June or July is the most detrimental time

to burn bunchgrasses. Before or after these months,

fire is less detrimental. Spring burns (April) are less

detrimental than fall burns (September-October),

although most species recover from fall burns in 1 to 3

years. Native plants with small canopies of loosely

arranged stems are more resistant to fire than larger

plants. Rhizomatous species such as Agropyron

dasystachyum and A. smithii tolerate fire well. Seral

species such as Poa sandbergii and Sitanion hystrix

also tolerate fire quite well at any time of the year.

Leafy bunchgrasses (Stipa, Fescue) are slower to

recover than stemmy bunchgrasses (Agropyron spp.,

Elymus, Sitanion). Early maturing species (Poa

sandbergii and Bromus tectorum) tolerate summer fires

well.

Most forbs tolerate fire well if burned in spring or fall.

Only forbs that remain green throughout the year, such

as Eriogonum spp., are severely hurt by prescribed

burns. Perennial forbs usually fully recover by the end

20
of the second growing season. Fire can enhance the

number and diversity of forbs because they have hard

seed that can be scarified by a fire (Wright 1985).

fire effects is largely dependent on season of burn.

Wright et al. (1979) provide a literature review of fire

effects that yield more detailed information, particularly

with regard to grasses and shrubs, than can be

Using information from Wright et al. (1979), gleaned from tables 1-3. The Fire Effects Information

Schmisseur and Miller (1985) prepared tables (tables 1 System (FEIS) developed by the Forest Service at the

- 3 below) identifying relative responses to burning of Intermountain Research Station’s Fire Sciences

some Great Basin and Columbia-Snake River Plateau Laboratory in Missoula, MT is another tool available to

range grasses, forbs, and shrubs. Relative severity of obtain information about fire’s effects on plant or

Table 1. Relative Response of Some Great Basin and Columbia-Snake River Plateau Range

Grasses to Burning. For species with two scientific names, the upper scientific name

represents the Hitchcock (1971) taxonomy, while the lower name represents the Barkworth

and Dewey (1985) classification of the Triticeae.

Severely Damaged Slightly damaged Undamaged

Needle-and-thread

(Stipa comata) Bluebunch wheatgrass(Agropyron spicatum)

(Pseudoroegneria spicata)

Threadleaf sedge

(Carex filifolia) Big bluegrass(Poa ampla)

Thurber needlegrass

(Stipa thurberiana) Columbia needlegrass(Stipa columbiana)

Cusick bluegrass

(Poa cusickii)

Idaho fescue

(Festuca idahoensis)

Indian ricegrass

(Oryzopsis hymenoides)

Nevada bluegrass

(Poa nevadensis)

Squirreltail

( Sitanion hystrix)

Cheatgrass

(Bromus tectorum)

Crested wheatgrass

(Agropyron desertorum)

Douglas sedge

(Carex douglasii)

Intermediate wheatgrass

(Agropyron intermedium)

(Elytrigia intermedia)

Plains reedgrass

(Calamagrostis montanensis)

Prairie junegrass

(Koeleria cristata)

Pubescent wheatgrass

(Agropyron trichophorum)

(Elytrigia intermedia

subspp. barbulata)

Riparian wheatgrass

(Agropyron riparium) (Elymus lanceolatus)

Sandberg bluegrass (Poa sandbergii)

Tall wheatgrass

(Agropyron elongatum)

(Thinopyrum ponticum)

Thickspike wheatgrass

(Agropyron dasystachyum)

(Elymus lanceolatus)

Western wheatgrass

(Agropyron smithii)

(Pascopyrum smithii)

21
Table 2. Relative Response of Some Common Great Basin and Columbia-Snake River

Plateau Forbs to Burning.

Severely damaged Slightly damaged Undamaged

Hairy fleabane

(Erigeron concennus) Astragalus(Astragalus spp.)

Arrowleaf balsamroot

(Balsamorhiza sagittata)

Common camandra

(Commandra umbellata) Hoary phlox

(Phlox canescens)

Matroot

(Penstemon radicosus)

Common sunflower

(Helianthus annuus) Littleleaf pussytoes(Antennaria microphylla) Munro globemallow(Sphaeralcea munroana)

Low pussytoes

(Antennaria dimorpha) Northwestern paintbrush( Cas tilleja angustifolia)

Coyote tobacco

(Nicotiana attenuata)

Pinnate tansymustard

(Descurainia pinnata) Douglas knotweed(Polygonum douglasii) Mat eriogonum

(Eriogonum caespitosum)

Flaxleaf plainmustard (Sisymbrium linifolium)

Uinta sandwort

(Arenaria uintahensis)

Plumeweed

(Cordylonthus ramous)

Flaxweed tansymustard (Descurainia sophia) Wyeth eriogonum

(Eriogonum heracleoides)

Red globemallow

(Sphaeralcea coccinea)

Sticky geranium

(Geranium viscossissimum)

Foothill deathcamas

(Zigadenus paniculatus)

Gayophytum

(Gayophytum diffusum) Tailcup lupine (Lupinus caudatus)

Tapertip hawksbeard

(Crepis acuminata)

Goldenrod

(Solidago spp.)

Tongueleaf violet

(Viola nuttallii)

Goosefoot

(Chenopodium sp.)

Lambstongue groundsel

(Senecio integerrimus)

Tumblemustard

(Sisymbrium altissimum)

Wavyleaf thistle

(Circium undulatum)

Longleaf phlox (Phlox longifolia)

Whitlowort

(Draba verna) Orange arnica(Arnica fulgens)

Pale alyssum

(Alyssum alyssoides)

Wild lettuce

(Lactuca sp.)

Purpledaisy fleabane

(Erigeron corymbosus)

Russian thistle

(Salsola pestifer)

Velvet lupine

(Lupinus leucophyllus)

Western yarrow

(Achilles lanulosa)

Wild onion

(Allium sp.)

22
Table 3. Relative Response of Some Common Great Basin and Columbia-Snake River

Plateau Shrubs to Fall Burning.

Severely damaged

Antelope bitterbrush

(Purshia tridentata)

Big sagebrush

(Artemisia tridentata)

Black sagebrush

(Artemisia nova)

Broom snakeweed

(Xanthocephalum sarothrae)

Ceanothus (nonsprouting)

(Ceanothus sp.)

Cliffrose

(Cowania mexicana)

Low sagebrush

(Artemisia arbuscula)

Slightly damaged

Curlleaf mahogany

(Cercocarpus ledifolius)

Desert bitterbrush

(Purshia glandulosa)

Mountain mahogany

(Cercocarpus montanus)

Mountain snowberry

(Symphoricarpus oreophilus)

Serviceberry

(Amelanchier alnifolia)

Silver sagebrush

(Artemisia cana)

Undamaged

Ceanothus (sprouting)

(Ceanothus sp.)

Common snowberry

(Symphoricarpos albus)

Gambel’s oak

(Quercus gambelii)

Horsebrush

(Tetradymia canescens)

Rabbitbrush

(Chrysothamnus sp.)

Three-tip sagebrush

(Artemisia tripartita)

animal species or plant communities. As of June 1992,

the system had information on about 500 plant species, 30 wildlife species, and 10 plant ecosystems.

Plans are to add species and ecosystems to the

system over the next several years. The BLM has

installed the FEIS on computer at the Boise Interagency Fire Center (BIFC). For assistance in accessing the BIFC computer, BLM employees can contact

their District Information Resource Manager, or Branch

of Fire Science, BIFC, at (208) 389-2456. Forest

Service employees should contact their local DG

system manager to access the system. State agency

employees should contact their designated Fire Effects

System coordinator, or their local Forest Service

cooperative fire manager.

Potential Drawbacks to Burning

All planning for use of prescribed fire must take into

consideration the Clean Air Act (P.L. 95-95) and the

public interest (Kilgore and Heinselman 1990 citing

Ferry et al. 1985). Although prescribed fire may be an

efficient method of meeting management objectives,

short-term effects of fire on air quality may violate

certain air quality standards. The Environmental

Protection Agency (EPA) has developed National

Ambient Air Quality Standards (NAAQS) for six air

pollutants, including particulate matter. The Clean Air

Act requires all federal agencies to comply with all

federal, state, and local air quality regulations (Kilgore

and Heinselman 1990 citing Haddow 1985). Proposed

standards for particulates will include both inhalable

and respirable particulates, much smaller sized

particles than previous standards have addressed.

Most smoke particulates emitted from prescribed

burning are in these small size classes (Kilgore and

Heinselman 1990). Airborne particulates are the

primary pollutant of wildfires and prescribed burns and

account for 23.7 percent of all particulates emitted into

the atmosphere (Wright and Bailey 1982, Martin et al.

1977). The most objectionable feature may be the

effect on visibility which is, however, generally shortlived. Large particles settle out rapidly, but small

particles may remain suspended for several days

23
(Martin et al. 1977). The effect of small particles on

humans may not be as innocuous as once thought, but

the effects remain unclear (Sandberg et al. 1979).

The issue of field burning has surfaced in the region

recently (Dewey Rand Jr. commentary, June 26, 1992,

Capital Press, Salem, OR). An organization called AIR

(Air Improvement Resolve), based in La Grande, OR,

has submitted an initiative petition to phase out burning

of all crop fields in three years and prohibit slash

burning after Jan. 1, 1993. The petition has been

submitted in a largely agricultural county lacking

heavily populated cities and urban areas, such as in

the Willamette Valley, Oregon, where smoke from field

burning has become a major political issue. Use of fire

to establish and maintain “natural” ecosystems on

public lands may face similar opposition.

Mechanical Control

Mechanical plant control is an alternative to chemical,

biological, or fire control methods (Vallentine 1989). It

can also be combined with one of the alternative

approaches, either as a preparatory or follow-up

treatment, or two different mechanical methods may be

combined to accomplish the desired treatment

(Vallentine 1989).

Vallentine (1989) listed the following key factors that

should be considered in selecting the best mechanical

method for a specific plant control job:

1.

2.

3.

4.

5.

24

Management objectives - what is the primary use

as well as other multiple uses; is selective or total

plant control being sought; will the release and/or

rejuvenation of desirable, residual plant species be

sufficient, or is simultaneous seedbed preparation

and artificial revegetation planned.

Characteristics of target species - density, height,

diameter of stem, growth form, brittleness, and

sprouting ability.

Characteristics of secondary species - whether

desirable plant species will be released; whether

potentially undesirable plants may increase or

invade; or whether all resident species need to be

replaced.

Topography and terrain - roughness, steepness,

heterogeneity, erodability, and amount of woody

debris on the ground.

Kind of soil - depth; fertility; soil moisture relationships; amount, size, and attachment of rock; and

degree of soil compaction.

6. Site potential - anticipated cost-benefit ratio;

productivity versus rehabilitation.

7. Follow-up required- how long will benefits last;

what other treatment must follow; what maintenance will be required.

Several mechanical methods can successfully control

sagebrush. Plowing or disking will destroy sagebrush

and prepare a good seedbed for revegetation where

there is not an adequate understory of desirable

perennials. Beating or shredding will destroy

aboveground portions of plants by cutting, beating, or

shredding and will leave a coarse layer of litter on the

ground surface. Railing will uproot or break off sagebrush on level, rock-free sites where the sagebrush is

large and brittle. Chaining is an effective, economical,

and widely applicable method for thinning stands of big

sagebrush and releasing grasses and forbs. It was

originally developed for eliminating stands of pinyon

and juniper, but has also been used successfully for

controlling many other woody species. If an adequate

understory is not present, a modified chain may be

used to prepare a good seedbed. Pipe harrowing has

been used to thin low, brittle brush. It is adapted to

rocky sites and rough terrain where more effective

machinery is not adapted, and provides sufficient soil

scarification to cover broadcasted seed on rocky

scablands, burns, abandoned roads, or excavation

scars (Blaisdell et al. 1982, Vallentine 1989).

Plummer et al. (1968) described interseeding (seeding

directly into established vegetation usually with only

partial reduction of competition) as a widely successful

means of improving vegetal cover. Using drills provided with 6 to 24 inch wide scalpers that effectively

eliminate cheatgrass and cluster tarweed is a satisfactory means of seeding shrubs and perennial herbs in

competitive annual types. Interseeding is also effective

in establishing shrubs and forbs in perennial grass

stands.

Haferkamp et al. (1987) found a land imprinter to be

effective in providing seed-soil contact for broadcast

seeds on loose or coarse textured soils. They suggested the need for prior seedbed preparation,

designed to control competing vegetation, in the

northern Great Basin or Palouse Prairie.

The basic mechanical weed control options for

cheatgrass are spring tillage followed by seeding, or

spring tillage with a summer fallow maintained until fall

seeding (Evans and Young 1987). The primary

difference between the two is that the fallow period

conserves and stores moisture and allows soil nitrate

to accumulate. Moisture and nitrate availability both

interactively influence the establishment of perennial
grass seedlings. Too much nitrate will produce more

harm than good in dry years and when cheatgrass

control is not complete enough to prevent preemption

of available water and nitrate by weeds (see also

McLendon and Redente 1991).

The problem with mechanically maintained fallows

centers on the occurrence of alternate floras that are

conditioned by summer moisture events. Russian

thistle is a major problem on fallows. If the summer

stays dry, no follow-up mechanical weed control will be

necessary. If repeated summer rains occur, subsequent weed control will be necessary (Evans and

Young 1987).

According to Evans and Young (1987), the implement

most adapted to spring tillage is a light disk harrow with

minimum draft requirements. Complete turnover of the

seedbed would give maximum establishment of

perennial grass stands. However, this is not practical

on most rangeland sites and may not be economically

feasible even on sites where it is physically possible.

Tillage for weed control on rangelands seldom involves

secondary tillage to enhance seedbed quality. However, a small amount of time spent in additional

seedbed preparation may mean the difference between seeding stand success or failure.

Herbicide Control

Herbicides are an effective, necessary, and environmentally sound tool for the control of weeds and brush

on rangelands when properly used (Young et al.

1981). As a result, chemical control has been a widely

used means of removing unwanted or noxious plants

from rangeland (Vallentine 1989).

Herbicidal control has distinct advantages over other

plant control methods which explains their widespread

use (Vallentine 1989). These general advantages

include: (1) herbicides can functionally be used where

mechanical methods are impossible, such as on steep,

rocky, muddy, or many timbered sites, particularly with

aerial application; (2) they provide a variety of application methods ranging from individual plant treatment to

aerial broadcasting; (3) they provide a rapid control

method from the standpoint of both plant response and

acreage covered when broadcast applied; (4) they

have low labor and fuel requirements for application;

(5) phenoxy herbicides are generally cheaper than

mechanical control methods, but may cost more than

prescribed burning; (6) most herbicides are selective or

can be selectively applied so that damage to desirable

plant species can be minimized; (7) herbicides can

maintain a grass and litter cover which reduces soil

exposure to erosion; (8) they are safe and reliable

when proper safeguards are followed; (9) they can

often utilize regular farm and ranch spray equipment;

(10) soil-applied, but not foliage-applied, herbicides

can be applied over a relatively long time period for

brush control.

Disadvantages of using chemicals to control undesirable range plants include the following (Vallentine

1989): (1) no chemical control has yet proven fully

satisfactory for some noxious plant species; (2)

herbicides provide a desirable, noncompetitive seedbed for artificial seeding only under certain situations;

(3) cost of control may outweigh expected benefits on

low-potential range. This is also true of many other

treatment methods; (4) the careless use of chemicals

can be hazardous to nontarget plants in the stand and

to cultivated crops or other nontarget sites nearby, or

may contaminate water supplies; (5) lack of selectivity

may result in killing associated forbs and shrubs

important for livestock and/or wildlife; (6) the effective

time period for applying foliage-applied herbicides is

usually quite restricted.

Vallentine (1989) referenced several proven uses for

herbicides on rangelands. Herbicides have provided

selective control of undesirable plants as a sole

treatment, for example, control of green rabbitbrush

growing with grasses on foothill sites with 2,4-D plus

picloram (Evans and Young 1975), or removing big

sagebrush from bitterbrush and serviceberry sites with

clopyralid (Whisenant 1987). They have released

closed communities over which undesirable woody or

even herbaceous plants have gained dominance, for

example, juniper invasion on deep-soil benches (Evans

et al. 1975). Herbicides can be used to rejuvenate tall

shrubs and low trees for big game by top killing and

stimulating new growth from sprouts and seedlings, for

example, old-growth aspen stands given light rates of

2,4-D (Harniss and Bartos 1985). They are used to

eradicate small infestations of serious plant pests or

“environmental contaminants” (spotted knapweed,

musk thistle, etc.) not previously found locally.

Paraquat and 2,4-D have been used on sagebrushcheatgrass sites to achieve total plant kill to meet the

needs of chemical seedbed preparation for range

seeding or planting. Herbicides have been applied

postplanting to enhance establishment by selectively

controlling weed competition (e.g. dense annual

broadleaf weeds or perennial ragweed in a new range

seeding). Currie et al. (1987) applied atrazine at 0.5

pound/acre to remove annual bromes from perennial

wheatgrass or Russian wildrye stands. (Note: Atrazine

labelled for rangeland use is not currently being

marketed.)

25
Chemical Seedbed Preparation

The following discussion of chemical seedbed preparation is primarily from Vallentine (1989). Herbicides have

been successfully used as the sole treatment in

seedbed preparation. Seeding is done shortly after

spraying or after a fallow period maintained by herbicides. The techniques have been made feasible by the

development of effective herbicides, improved application methods, and the rangeland drill and selected notill drills. The best herbicide or combination of herbicides and a multitude of application and timing factors

must be carefully evaluated.

Chemical seedbed preparation and direct seeding

require that (1) the competing, resident vegetation be

killed or adequately suppressed and (2) the

herbicide(s) applied be broken down or leached away

by the time seeded species germinate or are not toxic

to seedlings of the seeded species (Eckert and Evans

1967). Chemical fallow during the previous growing

season has been more successful on low-rainfall sites

than spring herbicide treatment and direct seeding

(Young et al. 1969).

In May 1991, BLM issued its Final EIS on vegetation

treatment on BLM lands in 13 western states using

integrated pest management methods (Final Environmental Impact Statement Vegetation Treatment on

BLM Lands 1991). Use of selected herbicides was

included within the EIS. Herbicides cleared for use on

BLM lands are identified in Appendix M of the EIS. In

the following discussion of specific chemicals, if a

chemical discussed is not included in Appendix M of

BLM’s Final EIS for Vegetation Treatment on BLM

Lands in Thirteen Western States, its absence from the

list will be noted. Permission to use chemicals not

listed in EIS Appendix M will be difficult to obtain,

particularly if a chemical listed in EIS Appendix M can

be used in its place. To the best of our knowledge, the

chemicals listed in EIS Appendix M are allowed for use

on BLM administered lands in the thirteen western

states included within the EIS (does not include

California or western Oregon) if treatments are conducted in accordance with BLM procedures in Chemical Pest Control (USDI, BLM Chemical Pest Control

Manual, Handbook H-901 l-l) . Currently, Oregon and

Washington are under a court injunction and are under

further restrictions. Contact the BLM Oregon State

Office for further information if herbicide use on BLM

lands within Oregon or Washington is contemplated.

2,4-D - Aerial spraying with 2,4-D and drilling with a

rangeland drill have been effective for establishing

additional perennial grasses on sagebrush-grass and

weedy forb-grass sites with a fair understory of perennial grasses. This approach has been particularly

effective when the undesirable forbs and shrubs are

readily killed by 2,4-D and annual grasses have not

become a problem. A second herbicide application

may be required in the spring of the establishment year

if sprouting shrubs such as rabbitbrush are present or

a large number of sagebrush seedlings develop. A

disadvantage of this technique is that it tends to

remove desirable forbs as well as the targeted shrubs.

Paraquat - (Paraquat is not listed in Appendix M of the

Vegetation Treatment EIS noted above) Paraquat

application at 0.5 to 1.0 pound acid equivalent per acre

(a.e./A) in the spring after emergence of annual

bromes and drilling immediately afterward have been

an effective method of establishing perennial grasses

in the Intermountain Region (Young et al. 1984).

Paraquat is very quick acting, leaves no soil residues,

and permits planting of perennial grasses immediately

after spraying (National Research Council 1968).

Paraquat sprayed in the spring at rates as low as 0.5

pounds per acre has given adequate and consistent

control of cheatgrass for establishment of perennial

grasses (Evans et al. 1967). Spring paraquat application and seeding has been more effective for

cheatgrass control than fall application and seeding in

the Intermountain Region, since germination of

cheatgrass seed is only partially complete by the time

of fall spraying. Paraquat control of cheatgrass has

been greatly increased by the use of surfactants

(Evans and Eckert 1965). Where broad-leaved weeds

and shrubs are growing with cheatgrass, a hormone

herbicide such as 2,4-D should be combined with the

paraquat application (National Research Council

1968). Paraquat at rates up to 2 pounds has discolored

but not killed medusahead (Young et al. 1969). Spraying paraquat in bands in medusahead and drilling

down the center of each band has been used successfully to establish Hardinggrass and subclover in

California (Kay 1966, Kay and Owen 1970).

Dalapon - Dalapon at 2 to 6 pounds per acre has given

excellent control of medusahead where competitive

plants were quickly provided by seeding (Young et al.

1969). An effective combination of treatments for

establishing wheatgrasses in California medusahead

stands has been to burn in late spring, spray with 3

pounds of dalapon early the following spring, spray

with one pound of 2,4-D per acre later in midspring,

and seeding to wheatgrass in the fall (Torell and

Erickson 1967). This combination allows two successive crops of medusahead to be killed before perennial

grass seeding. Another promising combination with

medusahead has been tillage one year followed by

dalapon treatment of medusahead the following year

prior to wheatgrass seeding. Dalapon gives only fair

control of cheatgrass (Evans et al. 1967, Everson et al.

1969).

26
(Note: Dalapon was dropped from the list of approved

herbicides in the 1991 Final EIS for Vegetation Treatment on BLM Lands in Thirteen Western States

because producers were no longer manufacturing

formulations registered for control of annual and

perennial grasses in non-cropland areas.)

Atrazine - Atrazine gives longer suppression of resident vegetation than does paraquat. When applied at

1 pound per acre in October to control cheatgrass

during the following growing season, atrazine has

provided good seedbed conditions on semiarid sites in

the Intermountain Region for drilling the following

October (Eckert and Evans 1967, Young et al. 1969,

1984). Since atrazine is not selective between

cheatgrass and perennial grass seedlings, at least one

year should be allowed on semiarid lands for dissipation prior to grass seeding. The use of 4-inch-deep

furrows aids in the removal of contaminated soil from

the seedling environment (Young and Evans 1970).

When atrazine is used for chemical fallow, adequate

broadleaf control may require spring application of 2,4-

D (National Research Council 1968). A fall 1988

atrazine application coupled with removal of atrazine

treated soil from drill rows when drilling orchardgrass

seed has been successful in controlling yellow

starthistle and aiding establishment of orchardgrass on

a southwest Oregon foothill site (D.E. Johnson, Dept.

of Rangeland Resources, Oregon State Univ., unpublished data). A 2,4-D application the following spring

was planned but was not needed for starthistle control.

(Note: Atrazine is no longer labelled for use on

rangelands, however, restricted use labelling may be

possible and is being pursued.)

Glyphosate - On sites where the perennial resident

vegetation is highly competitive, total plant kill rather

than temporary suppression will be required.

Glyphosate kills a broad spectrum of annual and

perennial plant species and has a toxic residual of only

2 weeks or less. Effective resident plant kill is dependent on adequate growth for interception of the herbicide and favorable growth rates for adequate translocation. Not all plant species are completely killed.

Adequate carrier must be used to assure that the spray

mix reaches the understory plants as well as the

overstory plants. To improve effectiveness or reduce

application rates otherwise required, glyphosate is

commonly mixed with other herbicides before application for maximum plant kill. Drill seeding can take

place immediately following the glyphosate application,

but delayed drilling for 2 to 3 weeks permits desiccation

of the vegetation and easier seeding and also assures

no contact of the herbicide with the seed.

Other herbicides - Other herbicides that show promise

for chemical fallow or preemergence weed control in

range and other pasture seedings include clopyralid,

triclopyr, dicamba, and tebuthiuron.

Herbicides can be used in seedbed preparation only

when cleared for such usage. James A. Young has

recently stated that herbicides are not likely to be

available for use on rangelands because of the excessive cost of registering them and the relatively low

market demand for herbicides for rangeland conditions

(personal communication). The recent loss of Atrazine

and Dalapon illustrate the trend toward the reduction in

availability of chemicals for rangeland use because the

manufacturers are choosing to not register them for

such use.

Biological Control

Management practices commonly employed to reduce

undesirable plant populations include fire, herbicide

application, and mechanical controls such as chaining,

brush-beating, and chain sawing. These practices are

not always possible, nor are they always effective.

Where understory fine-fuels are absent, fires may not

carry. In close proximity to dwellings or where air

quality is a concern, fire is not always possible. Widespread herbicide use can be hazardous, if used

inappropriately or if precautions are not taken, and is

becoming less acceptable in our society. Mechanical

controls are often quite expensive and not costeffective on marginally productive lands and are often

not feasible on steep or rocky terrain. It may be difficult

to receive approval for chemical or mechanical treatments in Wilderness Study Areas. Biological control

needs to be considered as an alternative.

Cattle

On mountain summer range in the Intermountain

Region, cattle grazing tends to reduce the grass

component in the stand and increase the forbs and

shrubs (Vallentine 1989). Reduced grazing by cattle

has been associated with reduced vigor of bitterbrush

and increased vigor of grasses in California (Hubbard

and Sanderson 1961). In combination with deer

browsing, it has also resulted in senescence and

death, without replacement, of aging shrub stands, and

secondary succession back to grass-forb dominance

along the Wasatch Front in Utah (Urness 1990).

Vallentine (1989) states that observations in a number

of areas have suggested that it is advantageous to

graze some cattle on range managed primarily for deer

when cattle grazing is managed to make maximum use

of grasses and minimum use of bitterbrush and other

27
shrubs palatable to deer. Policies of managing stateowned big game range commonly include provision for

controlled cattle grazing to promote a better balance of

forage species.

Sheep

Proper timing (spring and early summer) and extent of

grazing by sheep alone or in combination with cattle

has resulted in a thinning of understory forbs and

grasses and an increase in the vegetative output of

shrubs (Vallentine 1989). Heavy fall grazing after a

spring rest from grazing for two or more years in

succession was recommended as a range improvement practice on sagebrush-grass range if the perennial grass presence was sufficient to respond. Spring

deferment and heavy fall grazing by sheep on native

sagebrush-grass range at Dubois, Idaho increased

grasses and forbs and decreased sagebrush (Laycock

1961, 1967).

Sheep grazing reduced Klamath weed in California if

sheep grazing was concentrated for short periods and

continuous heavy grazing was avoided (Vallentine

1989, Murphy et al. 1954). Bedell et al. (1981) and

Sharrow and Mosher (1982) demonstrated that sheep

could be effective in suppressing tansy ragwort. Lacey

et al. (1984) considered sheep grazing effective for

suppressing infestations of leafy spurge. Sheep have

long been a favorite for general suppression of weeds

on ranchsteads, residential estates, and other building

sites (Vallentine 1989).

Goats

Because of their ability to utilize and destroy coarse

forages, goats are well suited to brush control efforts

(Merrill 1975). Goats graze more diverse kinds of

vegetation and distribute themselves more evenly than

either cattle or sheep (Taylor 1983). Goats have been

used in many parts of the world for brush control. They

have been used successfully for controlling or suppressing such species as gorse, acacia, eucalyptus,

groundsel, Gambel’s oak, juniper, shin oak, hackberry,

and pricklyash (Richman and Johnson 1992). They

are currently being investigated at the U.S. Sheep

Experiment Station in Dubois, Idaho for leafy spurge

control and are successfully employed on public lands

in Montana for that purpose (Richman and Johnson

1992) .

In a study in central Oregon, Richman and Johnson

(1992) reported that there was strong seasonality of

use for plant species, especially shrubs, selected by

goats. Big sagebrush and green rabbitbrush were

consumed most heavily in the spring by does and in

the fall and winter by kids. Fall and winter sagebrush

and rabbitbrush consumption by kids was substantial.

However, diets consisted primarily of grasses and

neither sagebrush nor rabbitbrush were controlled by

goats during the study. Although insufficient western

juniper was present for valid statistical analysis,

observations indicated that juniper was readily eaten

by goats with the most energetic consumption occurring in the summer and fall. The several junipers on

the site less than 6 feet tall were completely stripped of

both foliage and bark. However, some of the juniper

were regrowing a year later which indicates a single

treatment may not be sufficient for control (Richman

personal communication). Martin (1975) concluded

that neither goats nor sheep could materially reduce

the growth and spread of juniper (among other shrubs)

on semidesert ranges in Arizona. Richman and

Johnson (1992) felt that because goats are selective

browsers and preference for plants changes with

season and plant development, they could consume

significant amounts of juniper, rabbitbrush, and sagebrush if management strategies could be developed.

Any use of goats must include close control over the

herd to prevent the escape of feral goats which have

caused major problems in areas such as Australia and

New Zealand. These animals will require herding and

fencing to prevent escape.

Insects

The biological control process has become increasingly complex; many restrictions have been added and

more steps are required for clearing new insect

introductions (Vallentine 1989). Employment of biological control of noxious plants by insects has been

limited, in part, because of two principal factors

(Huffaker 1959): (1) Lack of consensus in acceptance

of a plant as undesirable. (2) Fear that risk (i.e.

damage to desirable plants) is too great compared with

chances of success.

Biological control with insects is not a short-term

alternative but rather a long-term program that requires

many years of research and development with the

outcome never being highly predictable (Vallentine

1989). Biological control alone is seldom totally

effective, but rather requires the use of supplemental

control methods to additionally stress the target plant.

Although insects have received primary attention for

biological control of weeds, other natural enemies with

potential control value include fungi, bacteria, viruses,

parasitic higher plants, plant mites, nematodes, and an

assortment of other small or microscopic animals

(Andres et al. 1976). Kennedy (1992) discussed

effective use of bacteria to inhibit cheatgrass growth

which resulted in greater wheat yields.

28
Biological control by insects has been successful to at

least some degree on the following: pricklypear in

Australia; St. Johnswort or Klamath weed (Hypericum

perforatum) in California, Oregon, Washington, Idaho

and Montana; Tansy ragwort (Senecio jacobaea) in

California and Oregon; and on mesquite in Texas

(Vallentine 1989). Current research in the United

States and Canada is being directed against selected

noxious plant species of grazing lands including:

Canada thistle (Cirsium arvense), musk thistle

(Carduus mutans), bull thistle (Cirsium vulgare),

Russian thistle (Salsola kali, Russian knapweed

(Centaurea repens), and related knapweeds including

yellow star-thistle (C. solstitialis), halogeton (Halogeton

glomeratus), hoary cress or whitetop (Cardaria draba),

leafy spurge (Euphorbia esula), Dalmatian toadflax

(Linaria dalmatica), saltcedar (Tamarix pentandra), and

selected native species such as silverleaf nightshade

(Solanum elaeagnifolium) and broom snakeweed

(Xanthocephalum sarothrae) (DeLoach et al. 1986,

Goeden et al. 1974, National Research Council 1968,

Vallentine 1989).

D. Establishment Islands

Establishment of islands of desirable vegetation to

serve as mechanisms for dispersal onto surrounding

deteriorated rangelands has to our knowledge not

been evaluated. Seed and mycorrhizal dispersal out

from such islands may be an efficient and low risk

method of reestablishing desirable vegetation on

degraded rangelands. Spread of perennial grasses

from established stands on sites to which they are

adapted has been noted in the cases of crested

wheatgrass (Marlette and Anderson 1986 citing Hull

and Klomp 1966, 1967) and orchardgrass (D.E.

Johnson, unpublished data), both introduced species.

Marlette and Anderson (1986) noted little invasion by

native perennial grasses into established crested

wheatgrass stands. They suggested that one reason

for sparse dispersal of propagules from the native

community is apparent in the close correlation between

the distribution of viable propagules and the distribution

of parent plants. Most of the native species possess

no specialized mechanism for long-range dispersal,

and such plants generally show an exponential decrease in the number of seeds deposited as distance

from the parent increases.

Spread of weeds from patches has been described.

Mack (1981) described the spread of cheatgrass

(Bromus tectorum) as being like a coalescing of

“leopard spots” which rapidly covered the Agropyron

spicatum Province between 1919 and 1930. All that

was apparently required was unoccupied, suitable

space. In a paper presented to BLM’s National Weed

Evaluation Team in 1991, James A Young (USDAARS, Reno, NV), Bill Phillips (BLM, Susanville, CA

Dist.) and Glen Nader (Cooperative Extension Service,

U. of Calif.) provided a history of medusahead in the

western Great Basin. During the 1970s there was a

sudden surge in medusahead distribution, from small,

scattered, infestations, when the Tablelands area

northeast of Susanville was converted from low

condition bluebunch wheatgrass/needlegrass/

cheatgrass to dominance by medusahead. About

50,000 acres became dominated by medusahead in

less than a decade. Moody and Mack (1988) simulated expansion from foci and concluded that small

satellite foci present a greater expansion potential than

a large central foci.

Efficacy of establishment islands of desirable native

species needs to be evaluated. Seed and mycorrhizal

dispersal, and establishment and survival patterns all

need to be studied. Methods of facilitating dispersal

and planting of desirable plant seed also need study.

IV. Plant Materials

and Seed Technology

A. Ecotypic Adaptation vs.

Phenotypic Plasticity

Hoekstra (1992) presents an evocative argument for

use of locally adapted ecotypes when using native

species for revegetation. His argument is essentially

that ecosystems developed with such a diversity of

genes and that ecotypes of the same species (assuming genetic differentiation) are not interchangeable in

the same niche. Ecosystems are essentially customtailored, with the genetic makeup of individuals adjusted to fit the stress parameters of individual environmental niches. Hoekstra is concerned about inbreeding

that may lead to genetic mediocrity. In the context of

forests, he states ‘The evidence, however telltale,

suggests that the genetic specifications of nature differ

broadly from the ones we cultivate, and that we need

to research the difference between the wild forests of

evolution’s vintage and the domesticated ones we

make.” (page 56).

Unfortunately, very little is known about genetic

variability versus phenotypic plasticity in native species

likely to be used in restoration of severely degraded

Great Basin and Columbia -Snake River Plateau

rangelands. Large phenotypic plasticity for a given

29
species might allow use of seed produced from other

locations. Large genetic variability would suggest the

need to use local ecotypes in revegetation/restoration

attempts. Research results suggest that for a number

of species, genetic variability is a factor for seed

germination characteristics, time of flowering, etc., but

that a great deal of within-population variability also

exists.

In a study of variation in germination response to

temperature in rubber rabbitbrush, Meyer et al. (1989)

were not able to clarify whether between-population

differences in germination patterns represent ecotypic

(genetic) differentiation or the response of a generalist

genotype to environmental conditions during seed

maturation. They referenced Naylor (1961) to suggest

that date of floral bud initiation is probably under

genetic control, which in turn strongly influences date

of seed maturation and thus the environmental conditions under which the critical final states of seed

maturation take place. Meyer et al. (1989) concluded

that germination patterns of rubber rabbitbrush are

probably not under rigid genetic control, but represent

an integration of genetic and environmental factors.

According to Meyer et al. (1987), seed germination

patterns are ultimately under genetic control if they can

be explained in terms of their adaptive significance.

They cite several studies which suggest that while the

limits of variation of germination patterns are set

genetically and are heritable, the influence of environmental factors during seed development on the mother

plant is significant. Within-species variation in germination characteristics can be approached at several

levels including: (1) differences among populations; (2)

differences among plants in a population; (3) differences among seeds on an individual plant; and (4)

differences among harvest dates or years of production

(Meyer et al. 1987). Common gardens and

outplantings used for evaluation of plant materials at

the post-establishment stage could provide the necessary contrasts to study differences in what should be

genetically similar materials ripened under contrasting

conditions and of what may be genetically contrasting

materials ripened under similar conditions.

Meyer et al. (1987) reviewed the literature for five

shrub species relative to intraspecific variation with

respect to seed germination. Studies have suggested

that winterfat exhibits population differences in germination response to temperature and to osmotic stress.

Within a population, year-to-year differences were

found in both viability loss through time and rate of

afterripening. The possibility of between-population

differences was suggested for four-wing saltbush, but

conclusive evidence was lacking. Source differences

in antelope bitterbrush seed germination was also

suggested but the absence of clear patterns was

noted. As noted above (Meyer et al. 1989), seeds of

rubber rabbitbrush from different habitat types did

respond differently to temperature. Work by the

authors at the time of publication was suggesting

source differences in seed germination for big sagebrush both among and within subspecies. Meyer and

Monsen (1990) have concluded that even though siteand year-specific weather events have an overriding

effect on the probability of successful establishment for

rubber rabbitbrush and big sagebrush, use of seedlots

collected at similar sites increases the probability of

successful establishment.

In a series of papers, Rice and Mack (1991 a,b,c)

discussed the tremendous phenotypic plasticity of

cheatgrass (Bromus tectorum). They suggested that

fitness within field populations of cheatgrass may be

largely environmentally determined. Genotypic

similarity between large and small individuals in natural

plant populations and the prevalence of “safe sites”

suggest that microenvironmental variation in resources

often overrides genetic differences in determining plant

fitness. Lack of density-dependent mortality in annual

plant populations (in species such as cheatgrass) at

high density may be important in preserving withinpopulation genetic variability. Thus for most traits,

ecotypic differentiation is not much of a factor. However, an ecotypic response, time to flowering, by

cheatgrass was significant. Also, in terms of net

reproductive rate, evidence for local adaptation in

cheatgrass was obtained in populations from habitats

representing environmental extremes. Thus, even with

a great deal of phenotypic plasticity, cheatgrass does

exhibit ecotypic variability for some traits.

Clary (1975) studied potential ecotypic adaptation in

squirreltail (Sitanion hystrix). Relative phenological

development could be predicted by a climatic scale

representing temperature and moisture conditions at

the original collection sites. Plant size and dry matter

production could not be predicted as reliably, suggesting that the primary factors which influence morphological and production characteristics may be more

numerous or complex than those which influence

phenology. In a related paper, Clary (1979) stated that

ecotypic responses to climate are often through

variation in phenology and dry matter production,

whereas responses to grazing are often variation in

growth forms and phenology. Responses to edaphic

variation may be physiological rather than morphological or phenological. Citing several references, Clary

(1979) observed that ecotypic differences in grasses

have been shown to occur in numbers of vascular

bundles, in stomatal density, and in numbers of

mesophyll cells. Other references were cited to note

epidermal variations, and photosynthetic and respira30
tion rate variations within species. Clary (1979) noted,

however, that for grasses, it appears that most withinspecies variation in internal structure and photosynthesis has been demonstrated among genotypes developed in plant-breeding programs, rather than among

naturally occurring races.

We need more information about the roles of ecotypic

variation and phenotypic plasticity of plant species

used in revegetation/restoration of Great Basin and

Columbia Plateau rangelands.

Native Plant Breeding and

Evaluations of Accessions/Cultivars

USDA-ARS Research Geneticist Tom Jones (Forage

and Range Research Laboratory, Logan, Utah) is

pursuing a native grass breeding, germplasm collection, evaluation, and improvement program. Species

are identified that are potentially important for revegetation efforts, but are specifically limited by a feature

which can likely be ameliorated by plant breeding (e.g.

seed dormancy, awned seeds, first year growth rate).

Some of these problems can be approached by

hybridization with a closely related taxon. Germplasm

is collected from native sites and evaluated in smallplot trials. Selection is practiced on promising naturally

occurring populations and on polycross populations

generated by hybridization between individuals of the

identified populations. Taxa of interest currently are:

bluebunch wheatgrass (Pseudoroegneria spicata),

Snake River wheatgrass (Elymus lanceolatus ssp.

wawawaiensis), thickspike wheatgrass (E. lanceolatus

ssp. lanceolatus), indian ricegrass (Oryzopsis

hymenoides), basin wildrye (Leymus cinereus), and

beardless wildrye (L. triticoides). In his 1991 annual

report, Jones stated that germplasm holdings for some

species are adequate, but collections for others remain

meager. Much collected germplasm remains

unevaluated. Nearly all released cultivars of these

species are populations identified as superior in

evaluations, but unimproved by artificial selection.

Breeding programs such as Jones’ may provide

materials for restoration of degraded systems with little

or no native seed source remaining. Hoekstra’s (1992)

admonition to beware of breeding in mediocrity needs

to be remembered, especially if a native seed source is

available to be expanded and ecotypic variation is

known or suspected.

Some native plant materials are currently being

evaluated by the Soil Conservation Service (SCS) and

the U.S. Forest Service (USFS) for the BLM’s Intermountain Greenstripping and Rangeland Rehabilitation

Project. The Aberdeen Plant Materials Center of the

SCS is conducting inter-center strain trials, some

Greenstrip plots, a display nursery and a row-spacing

trial at the Orchard Advanced Testing Sites near Boise,

ID of native accessions and cultivars including

thickspike wheatgrasses (including Snake River

wheatgrass), bluebunch wheatgrasses, basin and altai

wildrye, Indian ricegrass, fourwing saltbush, and

winterfat. Preliminary results indicate that some

species show excellent success even under drought

conditions (progress reports submitted to IGRRP, BLM,

Boise, Idaho).

The USFS Shrub Sciences Laboratory has been

conducting evaluations of accessions and cultivars of

bluebunch wheatgrass, thickspike wheatgrass, Lewis

flax, western yarrow, silver sagebrush, and fourwing

saltbush. Studies concerning the germination, seedling vigor, adaptability, burning tolerance, competition

with exotic annuals, and genetic manipulations are

being conducted with some or all of these species.

New collections were made of accessions of bitterbrush, Thurber’s needlegrass, bottlebrush squirreltail,

Sandberg’s bluegrass, and Minidoka penstemon

(progress reports submitted to IGRRP, BLM, Boise,

Idaho).

B. Seed Treatment

Plant parts dispersed with the seed sometimes have

mechanical and/or chemical functions that contribute

directly to germination success. Besides the commonly recognized function of seed dispersal, seed

coverings and appendages may interact with the

seed’s environment by affecting seed positioning, seed

fixation (anchoring), hydraulic conductivity, seed

protection, substance transfer to the embryo, and

regulation of seed respiration. The natural operation of

each of these functions should be considered before

sowing (or modifying for sowing) diaspores of rangeland plants (Booth 1987).

Indian ricegrass and winterfat have been studied

extensively with respect to germination characteristics

and to treatment of seed to enhance germination.

Summaries of seed treatments for these species are

provided in Appendix E. Similar information is needed

on other native species with potential for use in restoration of degraded rangelands to reduce the risk of failed

seedings.

Jones (1990) has recommended an interdisciplinary

approach including seed physiology, seedbed ecology,

seed technology, and plant breeding in an attempt to

solve the problems of Indian ricegrass dormancy, seed

production, and seedbed management practices for

31
various soils and to enhance establishment success.

He suggested that the potential of seeding Indian

ricegrass for improving rangelands can only be realized after low dormancy seed becomes available,

appropriate seedbed management practices are

developed, and seed shattering losses are reduced.

Some of these problems likely afflict other native

species. A similar recommendation might be appropriate for those which exhibit dormancy, erratic and/or

extended germination, or other related problems with

respect to achieving an established stand.

C. Seeding Techniques

Planting depth, rate, time, and related information for

several of the Vegetation Diversity Project priority

species is provided by Wasser (1982) and is listed in

Appendix B.

Restoration of degraded sites to native species with a

degree of plant diversity will require a mixture of

species. Most range seedings have involved single

species or simple mixtures rather than complex

mixtures. Wildlife and reclamation seedings are

possible exceptions (Vallentine 1989). BLM’s Intermountain Greenstripping and Rangeland Rehabilitation

Project (IGRRP) is currently using seed mixes of five to

nine species, including both native and introduced

grass, forb, and shrub species. Seeding of mixtures

has generally involved either broadcast seeding or

seeding each species in alternate rows when drill

seeding. Additional work is needed to develop and/or

evaluate methods for seeding species mixtures on

different sites and to incorporate clumped seed and

plant distributions. Collaboration between the Vegetation Diversity Project and IGRRP (Pellant 1990), which

is administered from BLM’s Idaho State Office, should

provide an efficient use of limited resources to approach this research need.

Booth (1987) discussed current technologies for

sowing ‘problem’ diaspores. Diaspores are seed,

fruits, fruits with attached structures, or even

flowerheads or whole aerial plants with several to

many seeds dispersed as a reproductive unit. Diaspore forms and functions vary by species. The

retention of these appendages is important in assisting

natural seed distribution and germination. Therefore,

on many species, we do not want to use breeding

techniques that would eliminate these structures.

Management (i.e. presowing treatments and methods

of sowing) should reflect the variation and the specific

adaptations of each plant. Diaspore management may

mean threshing seeds from their coverings to promote

germination; or implementing new technology, such as

fluid drilling, to sow intact diaspores thus using the

growth promoting relationship between seed and

appendages. Diaspores that are fluffy, hairy, awned or

otherwise incompatible with standard drills, or that are

adapted to surface germination and require assisted

fixation to keep the seed in place, pose special problems in mechanized sowing. Much of the following

discussion is from Booth (1987).

Special Drills

Seed drills were developed to plant slick seed. Other

kinds of diaspores, especially those with appendages,

may jam or bridge the drop holes in standard seed

drills (Pellant and Reichert 1984). The development of

metering devices that can handle fluffy seed, and their

incorporation into commercial drills (Wiedemann and

Cross 1981; Wiedemann 1982) has greatly improved

this situation. These drills provide the capability to

uniformly disperse appendaged seed and to place it in

the soil at an appropriate depth, or broadcast it on the

surface for seed adapted to surface germination.

Broadcasting

The practice of broadcast sowing has increased with

passage of reclamation laws requiring species diversity

and with the emphasis on native plants. In some

cases broadcasting has been the only practical

method, either because of the terrain or because of

“trashy seed” (Ries and DePuit 1984). DePuit and

Coenenberg (1979) found broadcasting small seeds

was better than drilling them 2.5 cm into the soil.

However, as a means for sowing seeds adapted to

burial, broadcasting is, at best, inefficient relative to

established plants from sown seed (Wood et al. 1982,

Herbel 1986). Broadcasting does not fix seeds in one

location. Seeds may be removed from the sown area

by secondary dispersal (Parady 1985) and/or plant

establishment reduced because fewer radicles penetrate the soil surface. Seedbed treatments that

disturb the soil surface before or after broadcasting do

increase the number of fixed seeds and often give

satisfactory results (Luke and Monsen 1984, Herbel

1986). Successful germination and establishment of

broadcast seed may be enhanced by: (1) surface

modifications, to better accommodate creeping and

lodging diaspores; (2) use of fluid and solid carriers to

enhance fixation of broadcast units; and (3) timing, to

use impending precipitation events or saturated

seedbeds to increase the number of diaspore appendages that become embedded in the soil.

32
Snowbank seeding

Some work has been done with sowing through or onto

accumulated snow. Winterfat diaspores dropped onto

the soil surface through 4 cm diameter holes punched

in 30 to 60 cm of snow established 25% of the pure live

seed (PLS) sown (Booth 1987). The bottom of a

snowbank is a protected site where fixation readily

occurs and moisture is not limiting; however, without

mechanized equipment the method is labor intensive

and slow. Another method is to broadcast seed over a

thin snow cover, 5 - 10 cm (2 - 5 in), on a sunny day to

allow the seed to melt through the snow to the soil

surface. This will ensure both escape from birds and

initial moisture for imbibition.

Pelleting

Pelleting of hairy or fluffy diaspores reduces clinging

and it makes mechanical dispersal easier and more

uniform. Properly functioning pellets anchor the

diaspore in place as the pellet dissolves. Kocher and

Stubbendieck (1986) showed that pelleting did not

reduce seedling establishment. If pelleting is used

diaspores should be pelleted as close as possible to

the planting date to avoid breakdown of pellets during

storage.

The use of hydrophilic pellets has been proposed as a

method of attracting water to the seed and thus

enhancing germination, but this has been shown to be

unsuccessful. Hydrophilic pellets did not increase the

germination or emergence of Elymus junceus (Berdahl

and Barker 1980). Various other methods of seed

pelleting and coating have been tried with range

grasses adapted to burial, and have not been successful (Hull 1959, Vallentine 1989). Pelleted seed requires

a prepared seedbed equally as much as nonpelleted

seed (Chadwick et al. 1969). Poor germination and

establishment have resulted from broadcasting of

pelleted seed by airplane or by hand, and this limitation

has not been overcome by increased seeding rates

(Bleak and Hull 1958, Hull 1959). In addition to

sparser stands, the cost of the pelleting and the extra

cost of handling the extra bulk have been high

(Chadwick et al. 1969). Some pelleting processes

have greatly reduced seed germination (Vallentine

1989).

According to Vallentine (1989) various substances

such as mud, fertilizer, and plastics have been used in

making three basic types of seed pellets: (1) coated

pellets in which individual seeds receive successive

layers of powdered material; (2) extruded pellets made

by pressing a pasty seed and soil mixture through

holes; and (3) compressed pellets made by running a

seed and soil mixture through pressure disks (Hull

1959). No pelleting process has shown consistent

advantages over using nonpelleted seed on rangelands, and the practice of using pelleted seed has been

virtually discontinued. The Bureau of Land

Management’s (BLM) Greenstripping Project has

evaluated pelleting recently and has judged the

method successful with regard to mechanical distribution of the diaspores (Mike Pellant, personal communication). However, the cost of having seed pelleted was

becoming prohibitive. Seed coating of fluffy or trashy

seed to obtain more accurate seed placement and

better seed mixing when using conventional seeding

equipment shows some promise (Vallentine 1989).

Hydroseeding

Pellant and Reichert (1984) have reported the use of a

hydroseeder to sow winter-fat diaspores with a mixture

of grass seed. Hydroseeding overcame problems of

bridging and seed separation encountered with other

machines, and it allowed the operator to select good

microsites, as opposed to uniformly sowing all landscape surfaces. Diaspore distribution was uniform

within planted areas. The method was labor intensive

and required large quantities of water to be hauled to

the field site.

Fluid Drilling (Gel Seeding)

The suspension of diaspores in a hydrocolloidal gel

overcomes the problem of synaptospermy (i.e. seeds

which are not dispersed but germinate alongside the

parent) while fixing diaspores to the soil surface in a

manner similar to natural mucilage (Booth 1985).

Unlike pelleting, mixing diaspores into a gel is not time

consuming nor does it require highly specialized

equipment. Planting equipment is commercially

available or can be fabricated (Ghate et al. 1981

Booth and Griffith 1986).

Fluid drilling does not damage soft seeds and can be

used to sow preimbibed and pregerminated diaspores.

This is especially important for those species where

water uptake is restricted by seed coverings or where

natural stratification is a problem (Booth 1985). Apparent advantages of sowing pregerminated diaspores of

rangeland plants is greatly complicated by wide

germination spans inherent in seedlots of many

wildland species. However, osmotic pretreatment may

synchronize germination of some of these species

(Bradford 1986, Morgan and Booth 1987).

In his summary, Booth (1987) stated that good seeding

management requires: (1) an understanding of the

mysteries of specific seedbed ecologies; and (2)

33 33
innovation in adapting methods of seed distribution and

fixation that will complement, rather than contradict,

those diaspore functions most critical to seed success.

D. Legume Inoculation

Vallentine (1989) discussed legume inoculation with

Rhizobium bacteria. The successful establishment and

I production of legumes in range and pasture seedings

depends on effective nodulation and nitrogen fixation.

Since Rhizobium remains near the infected plant it is

important that inoculated individuals are distributed well

across the landscape (Lowther et al. 1987a,b). Legume

seed should be treated with a good commercial

inoculant prepared from a strain of Rhizobium bacteria

specific for the legume being planted.

Mixing of inoculant and seed can easily be accomplished by mixing in a cement mixer or dry feed

blender or in a can with a closed lid. Legume seed

previously inoculated is now generally available for

purchase. When properly inoculated, legumes add

nitrogen to the soil and can materially reduce the

amount and cost of nitrogen fertilization. Under

California dryland conditions, range legumes effectively

nodulated were found to fix at least 52 pounds of

nitrogen per acre in one growing season (Holland et al.

1969).

E. Mycorrhizal Fungi

Inoculation

Mycorrhizal associations are present in most plant

species on semiarid lands. Within individual root

systems, the abundance of mycorrhizal colonization

will vary seasonally. In Artemisia tridentata, colonization appears to increase from a low of 47% in April to a

high of 80% in May. Soils in the shrub-steppe habitat in

southwestern Idaho tend to be low in organic matter,

low in available P and N, and have limited available

water. The ecological importance of mycorrhizae in

this habitat appears to be related to their role in

acquisition of nutrients. Following disturbance, these

lands are normally invaded by either nonmycorrhizal or

facultative mycorrhizal plant species, such as

cheatgrass. Plants colonizing the site the first year

following a fire do not form mycorrhizal root infections.

Studies on revegetation of severely disturbed land

indicate that the presence of mycorrhizae improves

survival and growth of host plant species (WicklowHoward, pers. comm.).

Wind and water are thought to be the main means of

dispersal for fungal spores in rangelands (Allen et al.

1989). A variety of mammals may be locally important

in dispersing spores of mycorrhizal fungi on rangelands

of central and eastern Oregon (Allen et al. 1992, Maser

et al. 1988).

Waaland and Allen (1987) conducted a study to

evaluate the relationships between vesiculararbuscular mycorrhizal (VAM) fungi and plant cover

following surface mining in Wyoming. They evaluated

the relationship of VAM to succession by dividing the

plants into functional groups. The early successional

species were predominantly annual members of the

Chenopodiaceae and Brassicaceae, which do not form

mycorrhizal associations (Pendleton and Smith 1983).

Agropyron species on site were mid to late seral and

formed moderate levels of infection. Shrubs tended to

have greater infection than co-occurring grasses with

the exception of four-wing saltbush (Atriplex

canescens).

Little appears to be known about VAM inoculation

requirements for restoration efforts of degraded

rangelands which are dominated by annual grasses

and forbs. VAM is probably not present or viable and

inoculation of transplants or topsoil would probably aid

in establishment of desired native plant species. VAM

indigenous to the area are probably needed (WicklowHoward, personal communication), or staggering the

introduction of species so that facultative mycorrhizae

associated plants are established first, then introduction of more obligate species is delayed until VAM is

present on the site (Allen and Allen, in press).

See also discussion of VAM in Sagebrush-Steppe

portion of Ecosystem Descriptions.

V. Maintenance of

Native Plant Diversity

A. Demography

The ability to maintain desired plant communities is

critical to long-term success of sustained multiple-use

of BLM lands. Current land-use practices include

livestock grazing, wildlife habitat management, mineral

exploration, and recreation. Traditional rangeland

management evaluates the impact of use through

several means (e.g., rangeland trend, key-plants or

areas, utilization). With the exception of rangeland

trend measurements, these techniques tend to specifically examine the forage species (Holechek et al.

1989) and ignore species that contribute only a small

34
part of the total biomass or cover for the site. Measured trend evaluates a combination of plant and soil

parameters for a specific area over the course of time,

and, if all species are included, may provide a method

for monitoring trend in plant diversity for a site under a

given management regime. Trend measurements,

however, do not provide detailed demographic information (e.g., birth, death, survival, life expectancy,

sources of mortality) that is necessary for predicting

responses of plant populations to disturbances or to

climatic changes.

We have very few data sets on the life expectancy of

most of the dominant perennial plants of the Great

Basin and Columbia-Snake River Plateau. Exceptions

include a few analyses of some pantograph studies

initiated during the mid-1900s at experiment stations in

Utah and Idaho. These include studies of three-tip

sagebrush (Artemisia tripartita), bluebunch wheatgrass, Indian ricegrass and needle-and-thread (Stipa

comata) in Idaho (West et al. 1979), and of shadscale,

winterfat and budsage in Utah (Norton 1978, Harper et

al. 1990). Some information on life expectancy can be

gained using ring counts of woody plants such as

sagebrush (Ferguson 1964), however, ring counts of

many woody species in salt-desert shrublands are

unreliable because of production of false rings.

Long-term demographic monitoring plots need to be

established in conjunction with climatic monitoring.

These plots would detect climatic conditions necessary

for successful establishment and maintenance of

native perennials, including rare plant species, and

would provide a demographic baseline that could be

used for incorporating demographic information into

rangeland trend measurements (Gardiner and Norton

1983, Owens et al. 1985).

B. Herbivory

Some research indicates that moderate grazing by

livestock will result in a reduction in herbage production

over that of ungrazed reference areas (Lacey and Van

Poollen 1981 report 68 + 22 % reduction, n = 20 sites),

but to our knowledge these studies are almost exclusively concerned with grasses and shrubs and tend to

ignore the forb component (e.g., Anderson and Holte

1981). It is clear that protection from grazing alone will

not guarantee an improvement in species diversity (a -

diversity, a combination of species richness and

abundance) because release from herbivory normally

results in an adjustment in dominance of the current

community (Rice and Westoby 1978, Smeins et al.

1976). There is a need for research to identify seasons of use and levels of use that will maintain all life

forms (shrubs, perennial grasses, and forbs) and will

provide information on species likely to be susceptible

to herbivory.

Recent results on the effect of spring grazing on

bluebunch wheatgrass indicate that grazing during the

period of apical meristem elevation (late-April through

May or June depending on the year) can severely

reduce the ability of this grass to activate lateral buds

for tiller replacement in subsequent years (Mueller and

Richards 1986, Richards et al. 1988, Busso et al. 1989,

Busso et al. 1990). Many native grasses may respond

similarly to grazing, but experimental evidence is not

available. Shrub tolerance to browsing is closely

related to location and viability of buds necessary for

regrowth. Browsing intolerant shrubs often have buds

for regrowth located on branches that are highly

susceptible to browsers, whereas tolerant shrubs have

viable buds for regrowth located throughout their

canopies (Bilbrough and Richards 1991). Little is

known concerning responses of native forbs to herbivory

C. Fire

The wildfire management strategy of the BLM, as with

most federal land management agencies, has been to

control wildfires as soon as possible. This has potentially contributed to an increase in fire sensitive shrubs.

Long-term data sets indicate that even without grazing,

increases in sagebrush coverage can be anticipated

when fire is controlled (Anderson and Holte 1981, West

1983b). With periodic fires, grasses become dominant

and in some areas forbs can increase (Daubenmire

1975, Harniss and Murray 1973). Season of burning is

critical to achieving successful results following fires.

Prescribed burning of sagebrush stands between 30

and 60 years old may be useful in stimulating a natural

cycle without the detrimental effects (e.g., mortality of

perennial grasses and increases of exotic annuals) of

summer wildfires (Britton and Ralphs 1979, Wright et

al. 1979, Bunting et al. 1987). Controlled burning

needs to be investigated as a means of regulating

shrub dominance and of enhancing species diversity in

sagebrush ecosystems.

D. Climate

Climate strongly influences not only herbage production, but also survivorship of some perennial grasses

(Chamrad and Box 1965, Herbel et al. 1972) or can

result in shifts in dominance when season of peak

precipitation shifts (Pieper and Donart 1973 cited in

Holechek et al. 1989). Models that predict the ecosys35 35
tern responses to various global climate change

scenarios indicate that elevated levels of CO2 and

changes in precipitation pattern are the variables that

account for most of the variation in biotic responses

(Hunt et al. 1991). A predicted doubling of the current

atmospheric CO2 concentrations to approximately 600

uL/L by 2050 may cause changes in primary production (Long and Hutchin 1991) and changes in the

dominant species. Higher CO2 concentrations may

favor exotic annuals over native perennials (Smith et

al. 1987). Studies of previous changes in climate

indicate that adjustments in plant dominance among

communities have lagged behind climate changes by

hundreds of years (Cole 1985, Shugart et al. 1986).

Research needs to focus on demographic and physiological responses of native and exotic species that

currently coexist in Great Basin and Columbia Plateau

plant communities under several climate change

scenarios (elevated CO2 changes in precipitation

amounts and seasons). Such experiments would help

managers in monitoring for early indications of the

impacts of climate change and in making knowledgeable management decisions should climate change

occur. This research must not be restricted to vascular

plants, but must include other parameters that may

feedback to the primary producers, such as fluxes in

soil nutrients and abundances of soil microbes associated with mineral cycling (Hunt et al. 1987, Perry et al.

1990). These studies will require long-term field

experiments (at least 5 years) to determine if semiarid

plants will eventually adjust to elevated levels of CO2

like some arctic species (Riechens et al. 1987).

VI. Special Status

Plants

Along with maintaining the dominant species that

constitute a plant community, managers need to

understand the life histories of the rarer components to

effectively manage them as well. Special status plants

are those species recognized by either state or federal

government as having few known extant populations

and as being potentially threatened with extinction.

Species are placed in this category if they meet one of

the following criteria: (1) they are a proposed or listed

threatened or endangered species under the U.S.

Endangered Species Act or by a similar state regulation (federal or state listed or proposed species); or (2)

they are suspected to be threatened or endangered,

but require further information for the species to be

proposed for federal or state listing (federal or state

candidate species).

Management for maintenance of special status species

requires a thorough understanding of the criteria for

maintaining a viable population. Information on

expected survival time, life history characteristics

including seedbank characteristics, and on the effect of

environmental variation on these factors is required to

determine if populations of special status species will

remain viable (Goodman 1987). Ideally, we would like

to determine the minimum viable population for all

special status plants, but this is not economically

possible.

Occasionally, management practices intended to

control pests like insect infestations or noxious weeds

may have detrimental impacts on species other than

the target species. Insecticide spraying to control

grasshoppers and crickets may also kill specialist

pollinators of rare plants. Use of broad-spectrum

herbicides to control noxious weeds may place the

survival of coexisting plants in jeopardy. If susceptible

pollinators or plants were known before treatments

began, then alternative management treatments could

be used.

It may be useful to utilize those special status species

for which some life history information is available in

demonstration studies that adjust management to favor

their maintenance or spread. An example is

Happlopappus radiatus which currently coexists with

cheatgrass on degraded rangelands and which is

suspected of being grazing sensitive. Cheatgrass

appears to competitively restrict seedling establishment of this special status species. Studies could be

initiated to examine the impact of removing grazing on

the growth, reproduction, and survival of

Happlopappus radiatus.

Another approach might be to concentrate efforts on

restoration of special status species on sites where

they once existed or potentially existed. Examples

include restoration of Allium aaseae on sites in Idaho

or of Polemonium pectinatum along drainages in

eastern Washington. These species are susceptible to

surface mining disturbances and to weed control with

herbicides, respectively, but show the potential for

restoration.

A third approach is to compare the life history characteristics of several special status species within a

common genus. The objective of these studies would

be a determination of common characteristics of these

special status species. Several genera have multiple

special status species located throughout Idaho,

Nevada, Oregon, Utah and Washington. Examples

include Astragalus, Eriogonum, or Penstemon. Few

studies have taken this approach. An exception is a

36
pair of studies comparing breeding systems between

rare and common Astragalus (Karron 1987, 1989).

A final approach is a study of common characteristics

contributing to the rarity of species with similar growth

forms. Growth forms might include annuals, bulb

forming perennials, rhizomatous perennials, and

nonclonal perennials.

VII. Concerns of Land

and Resource

Managers

Dr. David Pyke (Senior Rangeland Ecologist, Vegetation Diversity Project), Dr. Michael Borman (Rangeland

Ecologist, Vegetation Diversity Project), and Jerry

Asher (Research Coordinator, Oregon State Office)

visited BLM state offices in Idaho, Nevada, Oregon,

and Utah, and BLM district offices in Burns, Lakeview,

Prineville, Spokane, and Vale during February through

April 1992. These visits were intended to allow the

research scientists and the personnel in state and

district offices to become acquainted and to allow state

and district personnel direct input about issues and

concerns they would like to have addressed by the

Vegetation Diversity Project. Input varied across both

states and districts as a function of differences in

resource management needs included within each

jurisdiction. However, there were many common

issues and concerns voiced among the various states

and districts. A brief synopsis of the results of these

meetings is provided here. Specific comments from

each state and district visited are provided in Appendix

G.

With the exception of Utah, the Wyoming big sagebrush community type was considered to be the

number one priority for research needs for both

reestablishment and maintenance of native plant

communities. The Salt Desert Shrub community was

number one in Utah and second in priority for Nevada

and for the Burns, Lakeview, and Vale Districts in

Oregon.

Within Wyoming big sagebrush communities, the

conditions most commonly described as problems

requiring attention were: (1) extensive areas with

excessive sagebrush canopy coverage and very little

understory; (2) extensive areas of annual grass

domination with sagebrush and other components

effectively absent; and (3) areas of exotic weed

encroachment, particularly by medusahead rye and the

knapweeds.

Basic information that managers generally desired the

Vegetation Diversity Project to eventually provide

included: (1) techniques to successfully establish

desirable native plants; (2) information about the plants

which may be useful in restoration projects, especially

noted was a lack of information about forbs; (3)

management for maintenance of newly established

and of existing desirable native plant communities; and

(4) methods of preventing, or at least slowing, encroachment and subsequent spread of noxious weedy

species.

37
Technology Transfer

The intent of the Vegetation Diversity Project is to plan

and implement research and demonstration programs

which will provide new information and technology for

restoration/reclamation of those deteriorated rangelands in the Great Basin and Columbia Plateau on

which livestock management alone is not expected to

make significant improvements in the vegetation

condition in a reasonable time frame. The present

knowledge base is not adequate to design a management plan for restoration and maintenance of native

plants on this diverse area. For the BLM to accomplish

its objectives of maintaining vegetation condition where

it is currently acceptable and to restore desired vegetation where lands have been degraded, information

learned through the VDP must be transferred to BLM

land and resource managers and employees, livestock

operators, and other interested parties. Such information must also be provided to academia; other federal,

state, and local agencies; professional societies;

Congress; other BLM employees; and the general

public. Technology transfer programs may include, but

are not limited to, the following:

- A quarterly newsletter to provide (1) updated

information on VDP activities; (2) information from

District level projects and programs relating to the

VDP of potential interest to other Districts and

interested parties; and (3) pertinent literature,

conferences, professional meetings, etc.

- Annual meetings will be held to evaluate research

project progress, results, and future projections.

Research scientists, graduate students, and appropriate BLM personnel will participate.

- Develop workshops for District personnel which

present management (application) implications of

research results. Workshops will be incorporated

into field days as appropriate.

- Field Days at research/demonstration sites will be

conducted independently or in conjunction with

university Extension Service programs. When

possible, field days and research application

workshops noted immediately above will be integrated.

- Poster displays will be developed featuring VDP

studies and programs for presentation at conferences, field days, state and county fairs, and

professional meetings.

- Annual and final research reports and demonstration findings will be published and distributed to

appropriate audiences.

- Videos, classroom lectures, presentations to other

interested parties, pamphlets, and special in-house

bulletins will be prepared and presented/distributed.

- Research results will be expected to be submitted

for publication in refereed scientific journals within

the first 12 months after the completion date of a

study.

- Rangelands, and other similar publications, will be

utilized to publish interesting research and demonstration information not suitable for more scientific

publications and/or to provide nontechnical discussions of research and demonstration results.

- BLM public affairs efforts will be utilized to provide

public outlets.

- Expert Systems will be evaluated, used, and/or

developed as sufficient information becomes

available to help develop management programs for

reseeding, prescribed fire, grazing management,

etc. As an example, an expert system for prescribed burning on rangelands is being developed

by Wright et al. (1992). The system is described in

Rangelands vol 14, October 1992. It is being

evaluated by users outside west Texas for use in

other systems. We will attempt to either obtain a

license to evaluate it concurrently with others or to at

least interact with those evaluating the system to

determine its potential to provide a useful tool for

BLM and others in the Great Basin and ColumbiaSnake River Plateau regions.

An Expert System of the sort we are likely to use or

develop is essentially a knowledge based approach to

solving problems or making decisions. A computer

program emulates the problem solving strategies of a

human expert. By its nature, an expert system is

knowledge intensive. To achieve a satisfactory level of

performance, it requires a “knowledge engineer” to

work very closely with an expert to identify and describe how the expert makes decisions. Most expert

systems are written using production rules to capture

decision knowledge (i.e. if-then rules). Production

rules capture heuristic (rule-of-thumb) knowledge. An

expert system must be evaluated against the expert it

attempts to emulate. If several individuals are considered to be experts and we desire to capture the

expertise of each in an expert system, then an individual expert system, or at least individual modules

within a given system, must be developed for each. In

that way, individual decision making processes could

be addressed for a given problem.

38
Research and

Demonstration Tasks

The proposed studies presented below are not designed to be detailed study plans, but to provide

guidance in prioritizing the various aspects of this

project. The studies are written in a general fashion so

that projects could be conducted within any of the

communities listed below, but recognizing the priorities

given to each community type. We have attempted to

provide specific objectives for each study and to

prioritize each study by placing the study under one of

three priority levels (P1 being high and P3 being low

priority studies).

We recognize there are many ways that these objectives might be addressed. In some cases we have

suggested a general design with recommended levels

or ranges for replications. The prioritized list of studies

will be used as a guide in preparing requests for

proposals, in selecting, and in funding studies during

the duration of this project.

I. Plant Communities

for Study

The selection of communities for study will intentionally

be limited to upland shrub-steppe communities.

Riparian communities and Pinion-Juniper communities

will fall outside the scope of this project because the

needs and concerns within these types of communities

differ from those of the upland shrub-steppe and are

either currently addressed under another project or are

being reviewed for research needs under a separate

problem analysis.

A. PI - Wyoming Big

Sagebrush

The ecosystem that is the highest priority for study is

the Wyoming big sagebrush system. It received the

highest priority for three reasons: (1) it is the largest

ecosystem on BLM lands in Nevada, Idaho, and

Oregon/Washington and it is an important ecosystem

in northeastern California and Utah; (2) the unpredictable and low level of precipitation have made standard

revegetation practices only marginally successful; and

(3) it is historically more susceptible than other ecosystems in the Great Basin to invasions by exotic annuals

plants that reduce the species diversity of these sites

(Sparks et al. 1990).

Three to four communities (e.g., habitat types, range

sites, stable states) within this ecosystem should be

selected for specific studies. These communities

(listed from highest to lowest) should include

bluebunch wheatgrass (Pseudoroegneria spicata),

Thurber’s needlegrass (Stipa thurberiana), needle-andthread (S. comata), and Indian ricegrass (Oryzopsis

hymenoides) and should focus mainly on low precipitation zones (8-10 inch) for competition and restoration

studies. Study sites should be selected such that all

replicates of a study are in the same plant association.

If the sites have been disturbed, then replicated sites

should maintain similar species compositions and soil

types among replicates to ensure that the current

communities are in similar stable states.

B. P2 - Shadscale

Shadscale (Atriplex confertifolia) ecosystems within the

salt desert shrub will be given the second highest

priority. This ecosystem is of major importance to Utah

and Nevada and is a minor component in Idaho and

Oregon. Several plant associations within this ecosystem are reported to be widespread, thus worthy of

study. A prioritized listing includes associations with

(1) Indian ricegrass (Oryzopsis hymenoides), (2)

galleta (Hilaria jamesii) (3) winterfat (Eurotia lanata),

(4) giant wildrye (Elymus cinereus), and (5) Sandberg’s

bluegrass (Poa sandbergii). Studies describing the

successional transitions and states within this ecosystem are needed initially to provide an adequate background for the need of rehabilitation intervention or for

changes in management to allow transitions to states

of greater vegetation diversity.

C. P3 - Low and Black

Sagebrush

Low sagebrush (Artemisia arbuscula) and black

sagebrush (A. nova) ecosystems are lowest priority for

study under this project. The reason for their inclusion

are two-fold: (1) many of the plant associations in this

ecosystem are similar to Wyoming big sagebrush

communities, thus the successful principles for maintaining or enhancing diversity in the Wyoming big

sagebrush communities should be tested for their

applicability to similar low and black sagebrush communities; and (2) low and black sagebrush communities are interspersed throughout Idaho, Nevada, and

Oregon, however, this ecosystem is of lesser importance to Utah.

39
Il. Long-term

Monitoring of

Biological Diversity

Restoration of vegetation diversity on deteriorated BLM

administered rangelands carries with it the necessity of

understanding the natural diversity as it should be or is

desired to be (Dr. Lee Eddleman, personal communication). The objective of restoring natural diversity to

degraded rangelands requires first an idea of what

natural diversity should be and secondly what are the

differences between the desired communities and

deteriorated communities. Also, since vegetative

communities are dynamic in response to a dynamic

environment over space and time, long-term monitoring of relatively intact (near ‘pristine’) sites and of

similar ecological sites, but in deteriorated condition,

will provide critical information necessary to realistically

adjust management goals and objectives based on

dynamics of climate and community responses. This

information will also serve as the basis to evaluate

results of other proposed studies.

Biological diversity must be measured at different

levels of a hierarchy. Starting from coarser and

proceeding to finer scales these levels include: (1)

community diversity among watersheds or landscapes

(e.g., across a BLM District); (2) species and structural

diversity within communities; (3) genetic diversity within

populations. These measures of diversity need to be

made along a latitudinal, elevational, and disturbance

(e.g., within communities of different stable states)

gradient.

A. Diversity Across the

Great Basin

1. P1 - Evaluating Diversity Along Vegetation

Transects: Monitor climatic conditions,

edaphic condition, plant species richness,

production, composition and structural diversity of vegetation along a latitudinal and

successional vegetation transect with and

without livestock grazing.

A series of three to five watersheds should be located

along a north-south gradient from Washington or

Oregon into Nevada. All watersheds should have

similar soil conditions and consist of a series of communities such that transects within each watershed

could cross elevational ecotones associated with the

current upper and lower limits of sagebrush communities, Replicated pairs of undisturbed (near pristine)

and disturbed (degraded) communities would be

located within each watershed. The pairs of communities should represent different stable states. If feasible,

each community should have at least one, preferably

two or more, 1-ha livestock exclosures constructed to

provide grazed and ungrazed comparisons.

A series of permanent plots should be established to

sample vegetation canopy coverage and production of

all species of vascular and non-vascular plants. No

one method is adequate for measuring all plant

species, therefore several permanent-plot methods will

be needed. A protocol that identifies the appropriate

method for each species must be developed prior to

the first year’s measurements. Plots will be measured

at least twice a year. Once in middle to late spring to

monitor early season forbs, grasses, ephemeral

annuals and non-vascular, late-season plants and

once in early to middle summer (end of the growing

season) for perennial grasses, forbs, and shrubs.

A general description will be made of the edaphic

conditions of sites along the transect. Measure of

organic matter, N, P, K, and depth of top soil would

allow for comparisons among sites.

One climate station should be established at each of

the selected watersheds. These stations should

monitor daily temperature, precipitation, and soil

moisture at three depths, 5, 15, and 25 cm. If possible

stations should be located so that soil moisture measurements could be made in both undisturbed and

disturbed communities. If this is not possible the daily

soil moisture measurements should be conducted on

undisturbed sites and separate measurements gathered on disturbed sites during site visits.

Summarized results of these studies will be provided

semi-annually to the BLM’s Global Change Research

Program Data Center (GCRPDC).

2. P2 - Data-base of existing diversity: From

existing sources (e.g. Ecological Site Inventories, Natural Heritage Programs, etc.), develop

a data-base of community types and unique

species currently existing in the Great Basin

and Columbia-Snake River Plateau regions.

A data-base would be developed from existing Ecological Site Inventories (ESI) and from information in the

various states’ Natural Heritage Programs to identify

community types and unique species within the

community types on BLM lands in the Great Basin and

Columbia-Snake River Plateau regions. This information would provide a partial baseline for identifying

current diversity across these regions. This data-base

40
would help answer the following questions: (1) What

community types exist? (2) What unique species do

they harbor? (3) What critical role do they play (if any)

in maintaining regional biodiversity? (4) Are any of the

community types so rare as to be locally or regionally

in danger of extinction? (5) If the community type were

lost, what species would also be lost or, at least,

severely disadvantaged?

3. P2 - Genetic Diversity Along Gradients: Determine the genetic diversity of the dominant

plant species along a latitudinal and successional gradient with and without livestock

grazing.

One to three of the dominant species would be selected for starch-gel electrophoresis and/or Randomly

Amplified DNA (RAPD) studies to compare the quantitative heterozygosity of populations: (1) in pristine and

in degraded sites; (2) along a latitudinal gradient to

estimate spatial variation among populations; and (3)

between grazed and ungrazed sites with similar stable

states. Pristine and degraded sites should be near one

another so that exchange of genetic material is feasible

between populations. The latitudinal gradient will

provide a measure of the among population variation.

For the grazed and ungrazed comparisons, large (> 1

ha) long-term grazing exclosures should be used for

the ungrazed plots. These exclosures should be in

place for a minimum of 20 years to provide a minimum

time for selection, if any, to occur. Areas such as the

Idaho National Energy Laboratory may provide large

areas that have remained ungrazed for nearly 50

years. A minimum of 15 enzymes (preference for 20 or

above) should be examined.

4. P2 - Monitor changes at community and

landscape levels through time.

Track changes in vegetation diversity at the community

and landscape levels over time. Using satellite images

(AVHIR or TM) and Geographic Information System

(GIS) technology, map current community types and

compare among years for changes within communities

and among communities across BLM lands within the

project area. Specific attention should be made in

describing the expansion of weedy species. Attempts

will be made to determine associations between

changes in communities and in land uses or disturbances such as wildfires.

5. P3 - Faunal Diversity: Determine the species

richness and composition for some of the

major animal groups (e.g., insects, mammals,

birds) in pristine, degraded, and revegetated

communities.

Although the project emphasizes plant diversity across

the landscape, we recognize that ecosystems are

composed of interacting plants and animals Therefore, we propose complimentary studies to monitor

animal species composition and richness. These

studies could categorize animals into guilds such as

granivores, herbivores, and predators. Such an

organization may provide useful information for restoration efforts. For example, if degraded sites have

equal or higher numbers of granivores, but fewer

predators than nondegraded sites, then reseeding

efforts may be jeopardized by granivores. Restoration

efforts may require adjustments to compensate for the

expected granivory.

Study sites will need to be large enough to adequately

compensate for the sample area needed for animals

with large home ranges. Studies should be adequately

replicated across the landscape to provide a measure

of the variation among sites.

Ill. Competition and

Establishment

Restoration of plant diversity will require an understanding of factors contributing to plant competition

and establishment. Plant establishment is governed

not only by seed and seedling physiology, but by

beneficial and detrimental interactions among plants

during the establishment phase. Undesirable plants

tend to be particularly competitive with desirable plants

during the establishment phase (years 1-5) of development. Success in seeding rangelands depends in part

on a proper understanding of the competitive relationship among desirable and undesirable species during

the establishment phase and an understanding of how

management activities may reduce competitive interference.

Innate differences in competitive ability among desirable species may strongly influence the establishment

of species included in mixtures as well as with species

currently occupying a site. Properly applied seeding

methods and other cultural practices may sometimes

compensate for competitive differences among species

when attempting to establish a mixture of species.

Research on competition and establishment must

consider the type and length of control of undesirable

plants necessary to allow establishment of native

species. Methods for control and management of

undesirable plants are varied including mechanical

methods, herbicides, biological control, and fire.

Appropriate method(s) will depend on the specific

41
undesirable plant(s), site characteristics, management

objectives, and economics.

A. Competition: Evaluate the competitiveness of selected native plant species,

individually and in mixtures, and of ecotypes when

grown in association with undesirable plants; and

evaluate compatibility among desirable native

perennials to determine potentials for coexistence.

1. P1 - Determine density-dependent effects and

quantify relative aggressiveness of desirable

and undesirable species.

Studies using addition-series (density-dependent

effects), substitutive (aggressiveness) designs

(Silvertown 1987, Radosevich and Holt 1984), or other

appropriate designs should be used to determine the

relative competitive abilities of targeted species.

Competitive abilities of both desirable and undesirable

plants can be evaluated under highly controlled

conditions. Initial studies may be conducted in the

greenhouse to quantify density-dependent effects and

to evaluate aggressiveness of interacting species.

Greenhouse, or other off-site, experiments should be

conducted using soils from potential reseeding sites to

ensure inclusion of indigenous microbes. The root

zone in these studies should be maintained at temperatures similar to those occurring on potential

reseeding sites. Initial studies should evaluate

squirreltail and medusahead or cheatgrass because of

squirreltail’s potential to maintain and possibly expand

on sites dominated by exotic annuals. Future studies

should evaluate the competitiveness of basin wildrye,

Indian ricegrass, Thurber’s needlegrass, and

bluebunch/Snake River wheatgrass with exotic annuals. Additional studies can evaluate other species

identified as priority species in Vegetation Diversity

Project: A Research and Demonstration Program Plan

(May 1990).

2. P1 - Evaluate competitive interactions of

desirable and undesirable species under

variable climate conditions and soils of potential reseeding sites.

Follow up field studies (to the studies in 1 above) will

be required to further evaluate competitive interactions

of desirable and undesirable species under variable

climate and soils conditions (communities prioritized

elsewhere in this document) similar to those on which

reseeding efforts are anticipated.

Initial studies should focus on squirreltail as the

desirable native perennial plant and medusahead as

the undesirable plant. Squirreltail plants and seed

should initially be from proposed areas of intervention.

Similar evaluations for Thurber’s needlegrass and for

the native wheatgrasses would be of lower initial

priority.

This objective would have to be addressed in two

studies that could be conducted simultaneously: (a)

Seed known densities of squirreltail into small, replicated plots. Within those plots, maintain a range of

medusahead densities by hand weeding through the

growing season. Evaluate squirreltail and

medusahead germination, survival, growth curves,

production and reproduction under conditions of

varying densities. (b) Transplant plugs of squirreltail

seedlings into small, replicated plots during the fall.

Irrigate if necessary to initiate establishment. Use

vispore or some other method to suppress competition

during the first growing season then allow medusahead

encroachment and/or provide medusahead seed to

provide a range of initial densities. Evaluate established squirreltail survival, growth curves, production,

reproduction and spread across a range of initial

medusahead densities.

3. P1 - (a) Evaluate community level responses of

plants and soils, and individual plant responses to a shift in precipitation pattern from

predominantly winter to a more summer

oriented regime. (b) Determine the interaction

effects of precipitation pattern shifts, as

described in (a) above, and increasing CO2

levels on competitive interactions among

desirable and undesirable plant species.

Atmospheric CO2 levels are higher than they have

been in the recent past and are projected to continue

to increase. Higher levels of atmospheric CO2 have

the potential to increase both air and ocean surface

temperatures, which in turn influence global circulation

patterns. Shifts in global circulation patterns may alter

the distribution and amount of precipitation in the Great

Basin. Elevated CO2 levels should provide an advantage to cool-season (C3) species, but a shift to summer

precipitation should provide an advantage to warmseason (C4) species. Competitive interactions among

species may favor exotic annuals or native perennials

or may have no effect should major climate changes

occur in the Great Basin. Therefore, studies are

needed to evaluate potential effects climate change

may have on soils and on species composition,

richness and structural diversity of vegetation in the

sagebrush-steppe region.

42
Studies should examine (1) community level responses

(e.g. dominant grass, forb and shrub responses, both

physiology and structure; soil nutrient cycling; and

mycorrhizal activity) resulting from shifts in precipitation

season from predominately winter to a more summer

oriented regime, and (2) germination, establishment,

and interspecific competition among dominant species

in Wyoming big sagebrush communities. Both field

and growth chamber studies will be necessary. Field

studies could utilize rainout shelters coupled with

supplemental irrigation to provide shifts in precipitation

patterns. Measurements should include soil moisture

at incremental depths; soil nutrient dynamics, primarily

C, N and possibly P; mycorrhizal activity, spore counts

(spring, summer, and fall) and root colonization (during

boot stage of development); plant community composition on the basis of basal cover; seed bank composition; shrub and herbaceous root density and distribution; and photosynthetic activity, reproductive effort,

growth, and tissue nutrient contents of the dominant

shrub (Wyoming big sagebrush), grass (squirreltail,

bluebunch wheatgrass, Sandberg’s bluegrass, and/or

medusahead or cheatgrass), and forb (e.g. vetch)

species. Growth chambers should be used to evaluate

differences in air temperature, root temperature,

relative humidity, soil moisture, and concentrations of

CO2. Species to be evaluated should include: a

dominant forb; Wyoming big sagebrush; one of the

following cool-season perennial grasses: Thurber’s

needlegrass and/or bluebunch wheatgrass; Sandberg’s

bluegrass, Indian ricegrass, basin wildrye; exotic

annuals such as cheatgrass and/or medusahead; a

warm-season grass such as sand dropseed

(Sporobolus cryptandrus); and some special status

plants.

4. P1 - Develop demonstration/research plots to

compare methods of competition control to aid

establishment of desirable plants on annual

plant dominated sites.

Utilize methods identified by previous research which

have shown potential for control of cheatgrass and

medusahead. Atrazine, dalapon, and paraquat,

herbicides found effective in past studies, are no longer

registered for rangeland use. Evaluation of these

herbicides will not be considered as viable alternatives

with the Vegetation Diversity Project unless

reregistration for rangeland use becomes a reasonable

possibility. Study/demonstrations should evaluate level

of suppression and timing of control necessary for

establishment. Treatments should be replicated at

least 3 times to allow statistical analysis and interpretation of results. The following combination treatments

should be evaluated:

Seed squirreltail into established medusahead or

cheatgrass sites. Evaluate treatment combinations of

fire, tillage, livestock grazing, and herbicides such as

glyphosate and 2,4-D for effectiveness in control of

competition to aid establishment of desired perennial

species. Examples of treatment combinations include,

but are not limited to: (a) spring/early summer tillage

followed by fall, post-emergent application of

glyphosate and immediate seeding of the desired

species; (b) early summer fire, subsequent spring

glyphosate (post-emergence), and fall seeding; and (c)

heavy livestock grazing in late spring on annual grass

sites to reduce the annual grass seedbank and the

subsequent seedling population that would compete

with establishing desirable seed sown in the subsequent year. Objectives of the research are to evaluate

control of undesirable plant competition and stand

establishment of the desirable seeded species. Alternative seeded species could be bluebunch wheatgrass, Thurber’s needlegrass, etc. depending on site.

Logistics permitting, evaluation of techniques in both

medusahead and cheatgrass sites would be preferable. Collaboration with the Intermountain

Greenstripping and Rehabilitation Research Project

(BLM, Idaho State Office) may facilitate completion of

these studies.

5. P1 - Evaluate different sequences and patterns

of seeding mixtures of desirable species as

means of establishing diverse native communities.

Different sequences and patterns of seeding desirable

seed mixtures may help overcome problems associated with differing periods of growth and competitive

abilities and facilitate establishing diverse native

communities. Comparisons anticipated include: (1)

mixing herbaceous and shrub seeds together in a

single seed mixture and drill seeding; (2) mixing

herbaceous seeds together in a single seed mixture

and drilling immediately before transplanting shrub

seedlings (leave outside drill rows empty for transplanting shrubs); (3) providing spatial distribution by

separating herbaceous species sown by rows and

transplanting shrubs into outside drill rows; (4)

providing spatial distribution by stratifying species into

“islands” (perhaps by favorable microsites if variable

microsites are present on a site, less competitive

species can be concentrated on those sites more

favorable for establishment); and (5) providing temporal distribution by seeding perennial grasses first,

allowing establishment, and following with interseeding

or “island” patch seeding of forbs and shrubs. Species

will be site dependent and should represent potential

native species for the site. Row widths of 10 to 14

inches are most commonly used in range seedings.

Row spacing of 12 to 14 inches have been recom43
mended over narrower rows where there is a premium

on moisture and when deep-furrow drills are used.

Survival, production, reproduction, and movement of

the species involved will be an important part of this

study.

6. P1 - Evaluate the cost and effectiveness of

alternative techniques to incorporate broadcast

seed into the soil in areas where seed drills

cannot be used.

Various regulations and physical constraints restrict the

use of standard drills in many areas for which restoration is a priority. However, many seeds require

adequate contact with soil for successful germination

and survival. This study would investigate the feasibility of: (1) broadcast sowing seeds on such areas

during late autumn and using livestock to trample seed

into the moist soil; (2) animal or human drawn drag or

harrow; (3) transplants; (4) snowbank seeding; and (5)

broadcast only.

7. P2 - Evaluate the role of soil microorganisms

(mycorrhizae, rhizobium, etc.) in restoration of

native plant species on degraded sites.

Addressing this objective will require two studies that

could be conducted simultaneously:

(a) A study is needed to assess the changes in

the microbial community (population levels and species

composition) that may result from a shift to an exotic

annual community from a native plant community. Soil

samples from annual dominated and from native plant

dominated communities will be analyzed for microbe

density and species composition. Roots from desirable

plants in native plant dominated communities and from

medusahead, cheatgrass and knapweeds in undesirable plant dominated communities will be analyzed for

percent colonization by and species identification of

vesicular-arbuscular mycorrhizae (VAM).

A recently completed study from southern California

indicated that the VAM species composition changes

when communities become dominated by annuals.

The reintroduced perennial species can enhance

fungal recovery after five months in those systems

(E.B. Allen, pers. comm.).

(b) Field studies are needed to compare

establishment success by VAM infected and uninfected

plants. VAM infected seedlings of squirreltail,

bluebunch wheatgrass, Idaho fescue, and/or Thurber’s

needlegrass should be transplanted into medusahead

and/or cheatgrass dominated sites which have been

sampled for resident spore occupancy. A split plot

approach could be used to evaluate the influence of

competition suppression vs. no suppression during the

first growing season. Perennial grasses will be evaluated for survival, production, and level of VAM root

colonization. Plants and soils will be sampled for levels

of N and P.

8. P2 - Evaluate the genetic component of the

competitiveness of native perennials from

deteriorated vs pristine sites using (a) ecological genetics and (b) quantitative genetic

approaches.

Individuals of desirable species can often be found on

degraded sites, therefore, the potential exists that

these individuals have gone through a selection

process that favored genotypes that tolerate competition with exotic annuals. Species of interest include

squirreltail, bluebunch wheatgrass, Thurber’s

needlegrass, Indian ricegrass, basin wildrye, and

perennial forbs such as globe mallow, buckwheats,

and penstemon. Should evidence for selection be

found in degraded populations, then collections for

developing commercially available seed or for restoration should concentrate their seed collections on

desirable plants in degraded sites.

(a) Seeds and clones of desirable species

should be collected from individuals on degraded sites

and on pristine areas. Seeds and clones will be

categorized in a collection site (degraded vs. pristine)

and a relational hierarchy: populations, families, sibs or

clones. Seedlings or clones will be grown at a field

location with or without competition from an exotic

annual (e.g., medusahead or cheatgrass). The annual

will be maintained at a standard density and neighborhood area. A minimum of six populations, ten families

per population and ten sibs or clones per family will be

examined. Measured parameters will include:

aboveground biomass, seed production, tiller or clonal

production, and survival.

(b) The quantitative genetic approach might

use starch-gel electrophoresis studies to complement

ecological genetics studies of (a) above. Other

quantitative techniques may be more effective than

starch-gel electrophoresis. If so, they should be used.

Comparisons of quantitative heterozygosity would be

made of populations from pristine and degraded sites

located close enough to one another so that exchange

of genetic material is feasible between populations.

These studies would look specifically for reductions in

heterozygosity in degraded populations that might

indicate selection for quantitative traits that may favor

the survival and reproduction of individuals from

degraded populations.

This study fits within both Competition (Ill) and Plant

Materials (IV) categories. See also study IV.A.2.

44
B. Island Establishment: Evaluate the “island” approach to establish native

species into ecosystems dominated by exotic

annual plants.

1 . P1 - Compare techniques and costs for establishing islands of desirable species on lands

domlnated by exotic annuals.

This study would compare: (1) the use of transplants

vs. seeding desirable species; (2) preparation treatments (e.g., herbicide vs. fire, etc.); (3) the use of

mulches for competitor control and for growth enhancement; and (4) the location within the island.

These studies would use one island size (e.g., 10 x 10

m) (see comparisons of island size below). The

species should consist of two shrubs, two grasses and

two forbs. Island establishment of squirreltail in

medusahead is a high priority species for study in this

section. Records will be kept of all costs, including

labor, so that an economic analysis could be incorporated. Survival, growth and reproduction of the desirables and of the exotics will be measured annually

within each treatment. This study would be repeated

annually for at least three years to determine the

variability among establishment years.

2. P1 - Determine how island size, shape and

topographic location affect the establishment

and dispersal success of the study species.

Dispersal success can be measured as the establishment of a propagule away from the parent plant.

Success is achieved through a combination of sufficient reproduction and effective dispersal. The size

and shape of an island can affect the number of

individuals that are reproductive. Those individuals

along the edge of the island may have different (more

or less) reproduction relative to central individuals.

Locating islands on hillsides rather than valleys may

favor dispersal. The distance from the edge of the

island may influence this relationship. Size is an

important factor concerning invasion of exotics into

islands. The closer to the edge of an island the more

likely an exotic may invade the island. Size is also

important with respect to potential for loss of the island

to insects, small mammals, grazing animals, and fire.

Therefore, we believe that reproduction of desirable

plants relative to their distance from the edge of an

island needs to be determined. Results from these

correlations between distance and reproduction will

help to determine an appropriate size and shape of

island.

Estimates of establishment and survival of exotic

species relative to the distance from the edge to the

interior of the island are also necessary for determining

appropriate size and shape.

Island establishment of squirreltail in medusahead is a

high priority species for this study.

C. Specialized Methods for

Establishment: Evaluate the availability

of and need for specialized methods for seeding or

establishing desired species.

Much of the conventional equipment and technology

currently available for use on rangelands are not

allowed for revegetation efforts within BLM Wilderness

Areas and Wilderness Study Areas. Heterogenous site

conditions will require a variety of methods and equipment to revegetate target areas with desirable species.

Methods listed below merit attention. As they are

developed, new methods and equipment should be

evaluated as appropriate.

1. P1 - Evaluate the effectiveness of animals as a

dispersal agent for desirable and undesirable

species.

Provided seeds of desirable species could withstand

the digestive system of the animal, deposition of seeds

in fecal material may provide an effective means of

dispersal while concurrently providing a safe-site for

germination and establishment. Studies will be

conducted in two phases.

First, seed-passage tests would be conducted to

determine the ability of seeds of native desirable and

undesirable species to pass through the digestive

system of several domesticated and wild animals found

in this ecosystem and remain viable. These studies

will be compared to seed viability studies between (a)

seeds coated with materials to enhance their ability to

pass through the digestive system and (b) prefeeding

treatments to decrease the passage time within the

animal’s gut.

The second phase would take the promising techniques from the first phase and would examine the

germination and survival of seed in feces versus

broadcast seeding and transplanting techniques.

Should this technique appear to be useful for some

species, then an economic cost analysis should be

conducted to determine the cost effectiveness of the

various techniques.

45
This study could be combined with study III.A.6. to

provide a more comprehensive evaluation of animals

to both distribute and incorporate seed into the soil.

2. P3 - Evaluate the likelihood of livestock ingesting and dispersing undesirable species if

livestock grazing is used as a control for an

undesirable plant. Also, evaluate the dry lot

requirements for livestock that are used as

control agents of undesirable species.

Sheep are currently used to graze leafy spurge in

areas of the Great Basin and Columbia Plateau during

the time when leafy spurge is flowering and fruiting.

Studies need to be initiated to determine: (1) the

likelihood of leafy spurge seeds passing through the

digestive track of sheep and remaining viable; and (2)

the passage time for 100 % of the viable seeds. These

results could provide an estimate of the risk of dispersal of undesirable species by livestock. Species

such as cheatgrass, medusahead, various knapweeds,

statthistle, leafy spurge and white top should be

evaluated for potential of spread through feces.

D. Prescribed Fire to Control

Competitors: Evaluate the how prescribed fires can control undesirable annuals or

reduce sagebrush dominance.

Fire can be a useful tool in reducing competitors when

seeding native perennials and in releasing grasses and

forbs from competition with fire-sensitive shrubs.

For annual species that retain seeds in inflorescenses

as the remainder of the plant begins to dry and

senesce, there is a period when seeds are susceptible

to fire. Burning the plant too early (before flowering) or

too late (after dispersal) may have little or no effect in

reducing the seed population of annuals. Research

from California indicates that fire, when used at the

correct time, can reduce the next year’s population of

medusahead.

As sagebrush becomes dense, it can suppress grass

and forb production. Prescribed fire can be used to

release grasses and forbs because sagebrush is a fire

sensitive species. Provided desirable grass and forb

populations are sufficient and exotic annual populations are low, there is no need to reseed. However,

the levels of desirable vs. undesirable need to be

determined.

Total removal of sagebrush from a watershed is not

desirable, but we would like to create a mosaic with

sagebrush dominated areas and grass-forb dominated

areas. The development of techniques to achieve this

mosaic is necessary.

1. P1 - Demonstrate the window of opportunity for

prescribed fire to reduce medusahead seed

banks and densities.

We propose a demonstration study where prescribed

fires are set at three different times, (before dispersal,

mid-summer after dispersal, autumn after dispersal)

and an unburned control. Heavy spring grazing and

treatment with glyphosate during the spring before

burning should be evaluated as possible combinations

with fire. Heavy spring grazing may reduce the fuel

load too low for subsequent fire. Glyphosate prior to

seed set might prevent an additional seed source if fire

is delayed beyond seed set but still allow fire to remove

the medusahead litter mat. Video tapes will be used to

describe the pretreatment area, the burning techniques

used, and the postfire impacts. Combinations of fire

with post-fire treatments would be desirable (e.g. a

combination of spring burning and fall herbicide or

grazing followed by seeding desirable species). Tapes

will be distributed as an instructional aid. Tours would

be given the following spring to BLM, USFS, and State

fire and revegetation personnel to demonstrate the

effect of timing.

2. P2 - In sagebrush dominated areas, determine

the levels of desirable grass and forb populations and of exotic plant populations that

allows communities which develop after fires

(prescribed and wild) to become dominated by

desirable or undesirable plants.

This study would require an area with varying densities

(e.g., three to four density levels) of desirable and

undesirable plants associated with sagebrush. These

would be burned mid-summer (wildfire simulation) and

autumn (prescribed fire). The response of the grasses

and forbs will be measured using basal cover and/or

production during the next three years. Seed production per individual will be measured for the undesirable

plants. Soil N and P should be measured pre-fire and

at the beginning and end of each of the three subsequent growing seasons. This should be replicated

either in space or in time.

3. P2 - Enhance species diversity on sagebrush

dominated sites by using prescribed fire to

create a grass-forb mosaic within sagebrush

dominated sites.

For many wildlife species, the optimal habitat for all

stages of development may be a combination of

sagebrush dominated sites associated with grass-forb

46
dominated sites found in a mosaic across the landscape. A study is necessary to determine techniques

for burning sagebrush dominated sites so that only

parts of the sagebrush community burns, but the

associated vegetation remains intact. A criterion for

site selection includes site domination by sagebrush,

but with an understory of perennial herbaceous

vegetation with few or no exotic annuals in the understory. Two approaches might be compared. The first

approach would burn sagebrush during a season with

a higher fuel moisture level than those recommended

for total sagebrush control. The second approach

would use a propelled ignited fuel-gel sprayed on small

areas of sagebrush during winter when grasses are

covered by snow. These two approaches would be

compared in their ability to reduced the sagebrush

dominance while not injuring the associated grasses

and forbs. The influence of each technique on soil N

and P should be monitored throughout the study.

The study might require two phases. The first phase

would incorporate experimental small plots to test the

feasibility of these approaches. The second phase

would be larger demonstration level plots that would

include economic as well as biological analyses.

E. Nutrient Availability and

Competition: Determine the role of

nutrient availability and depletion, and of spatial

distribution of nutrients on the competitive ability

or establishment success of desirable and undesirable plants.

Disturbance often results in high nutrient (nitrogen)

availability which in Colorado tends to favor the

establishment and growth of exotic annuals. As N

becomes tied-up by soil microbes which are slowly

decomposing litter, the dominance of desirable native

plants appears to be facilitated. Also, relatively undisturbed sagebrush-steppe stands tend to show a high

degree of spatial variability in nutrients which may limit

the sites for exotic annuals to establish, however, the

spatial variability in stands of annuals is unknown. We

propose a set of studies to determine if nutrient

availability and nutrient cycling may influence the

growth and competitive abilities of desirable and

undesirable plants.

1. P2 - Determine if native perennials are able to

compete and establish better with exotic plants

if nitrogen is made less available by adding

carbohydrates to the soil.

Compare seedling establishment of mixtures of exotic

annuals and native perennials with and without carbohydrates (e.g., sucrose, slow decomposing mulch)

being added to the soil. These studies would be

conducted on disturbed and undisturbed sites and on

recently burned areas. Plant survival, aboveground

biomass, and seed production would be estimated for

each treatment. These studies would also monitor

nitrogen availability and VAM (vesicular-arbuscular

mycorrhizae) infection as well as the plant growth

characters.

2. P3 - Determine the ability of shrubs, forbs and

grasses to access nutrients when they become

available either in patches across the spatial

landscape or in pulses through time.

This study addresses the question of why sagebrush

becomes the overwhelming dominant on sites in the

absence of grazing and fire. Is sagebrush better able

to acquire nutrients found in patches or pulses?

Nutrient acquisition can be measured using stable

isotopes. Plant responses would include current year’s

growth and seed production. Mixtures of grasses,

forbs and shrubs, including desirable and undesirable

plants would be compared.

F. Animals as Agents of

Biocontrol and Stimulatory

Growth: Examine the effectiveness of using

livestock or other animals as control agents of

undesirable plants.

Insects are the common agent used in biological

control systems. We do not recommend providing

Vegetation Diversity Project support for preliminary

research on biological control of exotic species with

insects, however, we are supportive of this work and

believe it is a vital component in comprehensive weed

control program. Currently, insect biological control

agents are not the recommended course of action for

the control of most exotic species. However, we would

support cooperative demonstrations if proven insect

control agents were found that reduce competition of

exotic annuals during revegetation.

We advocate investigating grazing systems that can

limit the detrimental impacts of grazing on desirable

native plants while identifying opportunities for developing grazing systems to reduce undesirable species in

the ecosystem.

1. P3 - Evaluate the potential for use of domestic

animals to control or reduce brush cover and

increase grass and forb cover and production.

47
Examples of two potential studies are described below:

(a) Evaluate heavy fall use by sheep coupled with

spring deferment on sagebrush-grass range sites

to reduce sagebrush and increase grass and forb

cover. Sites for this study would require a high

initial sagebrush cover (greater than 12% crown

cover). The site must also contain a sufficient

coverage of desirable grasses and forbs (two or

more desirable plants per m2) to respond to a

reduction in sagebrush cover. These studies

would be conducted in small pastures. The study

would be conducted over several years (2 to 3).

Sagebrush survival, grass production and grass/

forb seedling establishment would be compared

against control sites. Broadcasting forb seed

before sheep entry to allow sheep to trample seed

into the soil may be also examined for its success

in enhancing forb establishment (see study ll.F.3.

below).

(b) Evaluate the potential for using goats to

manipulate shrub cover and density for maintenance of desirable communities. Evaluate spring,

summer, and fall goat (does and kids, in pairs and

separately) utilization of sagebrush, rabbitbrush,

and juniper to reduce shrub densities and cover

and enhance grass and forb production. Study

sites must be in areas where sagebrush and/or

rabbitbrush density reductions are desired and

where juniper encroachment onto shrub-steppe

sites is occurring and junipers are less than

approximately 6 feet tall. The study should

evaluate timing and intensity of goat use needed to

impact shrubs; goat diets; and shrub, grass and

forb responses. An absence of special status

plants must be a criterion for site selection.

2. P3 - (a) Evaluate the potential for late-spring

and early-summer grazing of grasses and forbs

by cattle and/or sheep to stimulate growth and

reproduction of bitterbrush.

(b) Evaluate the impact that ungulate browsing

is having on bitterbrush growth and reproduction.

Reduced livestock grazing pressure on grasses and

forbs is suspected in many areas of the western U.S.

to be reducing the growth and reproduction of many

desirable shrubs, such as bitterbrush through increased competition by grasses and forbs while deer

population increases have been placing greater

browsing pressure on desirable shrubs. A study or

combination of studies would be designed to determine

the role of livestock grazing of grasses and forbs and of

wildlife utilization of shrubs on the growth and reproduction of the shrubs. Increased cattle use during the

late-spring and early-summer season for a series of

three to five years may impact grasses and forbs

enough to allow bitterbrush sufficient time to respond.

After the three to five year study period, livestock use

would revert to early-spring and/or fall to allow grasses

and forbs to recover.

This study could be conducted using a combination of

small pastures with controlled grazing and of

exclosures to eliminate wildlife use. The bitterbrush

response would be measured by estimating currentyear’s growth and seed production and by monitoring

seedling establishment. Utilization of bitterbrush would

also need to be measured. Species composition

based on aboveground biomass of grasses and forbs

would be monitored annually to determine the effect on

the related grasses and forbs during the study period.

IV. Plant Materials

and Seed Technology

Research needs in the area of plant materials evaluation and seed technology include determining the need

for and identification of ecotypes of desirable native

species for use in targeted areas; seed physiology,

morphology, and viability; seedling and seedbed

ecology of selected plant species/ecotypes; and

technology required for production, handling and

planting of seed of the selected species/ecotypes.

Common gardens can serve as demonstration and

evaluation plots of species and ecotypes within species

for adaptation to site and of potential competitive

abilities.

A. Ecotypes and

Phenotypes:

(a) Evaluate ecotypic variability vs phenotypic

plasticity within native plant species adapted to

target areas.

(b) If ecotypic differentiation is an important

component, then identify and select those

ecotypes best adapted to target areas.

Very little appears to be known about ecotypic variability versus phenotypic plasticity in native species likely

to be used for restoration of severely degraded Great

Basin and Columbia Plateau rangelands. Large

phenotypic plasticity for a given species might allow

use of seed produced from other locations including

commercially available seed. Large genetic variability

48
would suggest the need to use site specific ecotypes in

revegetation/restoration attempts. If genetic variability

is significant, variables important to the relative success of the ecotype at its original site and at the target

area will need to be identified.

1. P1 - Compare the genetic and phenotypic

variability of important native species for

revegetation/restoration efforts in the Great

Basin and Columbia-Snake River Plateau.

Ecotypic differentiation can be evaluated through

common garden and reciprocal transplants or seedings

of species from sites with variations in elevation and

precipitation amounts and patterns. Commercially

available cultivars should be included in the studies.

Evaluations should be made of phenology, morphology, timing and rates of growth, survival, seed production, water use efficiency, and physiological functions.

Common gardens should be replicated in at least three

locations within the Great Basin. Each common garden

should have a climate station to monitor at least daily

temperature extremes and precipitation. Preferably,

soil moisture would be measured at 5, 15, and 25 cm

(or at 15 cm increments if using a neutron probe).

Species of immediate interest to the Vegetation

Diversity Project include the grasses squirreltail,

bluebunch wheatgrass, Snake River wheatgrass,

Thurber’s needlegrass, needle-and-thread, Indian

ricegrass, and basin wildrye. Forbs should include

globe mallows, buckwheats, and biscuitroots. Shrubs

should include sagebrush, rabbitbrush, bitterbrush,

shadscale, and winterfat. Work on bluebunch wheatgrass, Snake River wheatgrass, Thurber’s

needlegrass, and needle-and-thread was begun in

1988 for selections of superior genotypes by cooperators to the Intermountain Greenstripping and Rangeland Rehabilitation Project. We intend to coordinate

any collections of seeds of these species with the

IGRRP to reduce any duplication of effort.

2. P1 - Analyze seed germination characteristics

of important native species for revegetation/

restoration efforts in the Great Basin and

Columbia-Snake River Plateau.

Analyze seed germination syndromes from different

populations and commercially available accession of

the species of interest to the project (refer to IV.A.l.

above). Evaluate germination differences among

different populations under conditions that might

indicate heritable traits associated with germination as

opposed to environmentally-induced traits. Differences

in germination behavior among populations that are

related to genetics are crucial for determining whether

a species can successfully revegetate itself in any

specified environment. Those characteristics that are

regulated by environmental conditions of the parental

stock may help managers and seed producers match

environmental conditions that will improve the likelihood of establishment success.

3. P2 - Use quantitative genetic evaluations to

help evaluate genetic variability within and

among populations of natives.

In addition to common garden evaluations of native

perennial populations, quantitative genetic data would

help evaluate genetic variability within and among

populations. Starch gel electrophoresis has been used

to obtain quantitative genetic data. Use of DNA

fragment length polymorphism has been suggested to

recover genetic information quickly and efficiently if

fragments are generated using RAPD (Randomly

Amplified Polymorphic DNA) procedures. This technology apparently provides great power in describing the

basic genome of species, varieties, and individuals

(Kimball T. Harper, pers. comm.). Percent heterozygosity among populations, among families and within

families needs to be examined to estimate the quantitative variability within important dominant native plants

that are distributed over a wide geographic range.

Comparisons should be made between local populations and commercially available stocks of native

species. This would provide quantitative evidence for

the concerns of introducing populations from other

locations. See also studies ll.A.3 and lll.A.8.

4. P2 - Support native plant germplasm collections and evaluations for native plant breeding

programs.

Little work is being conducted on native grass breeding, germplasm collection, evaluation, and improvements for species from the Great Basin and the

Columbia Plateau. The exceptions are the efforts of

SCS Plant Materials Centers, USDA-ARS, and USDAFS. Species are identified that are potentially important

for revegetation efforts, but are specifically limited by a

feature such as awned seed, seedling vigor, seed

dormancy, etc. which can likely be ameliorated by plant

breeding. Care should be used when working with

self-pollinated species to reduce the likelihood that

characteristics eliminated by breeding are not totally

eliminated from the population. This may be achieved

by using impure (regarding the character) lines such as

combinations of dormant and nondormant seeds.

Also, breeding techniques that culminate with backcrosses into the native or into the key species’ parental

line are encouraged. Backcrosses tend to retain a high

proportion of the original genotype in the offspring

along with the character that was selected. This would

then allow natural selection to favor genes for each

location including those genes removed by the breed49
ing process. Continuation and expansion of this work

should be encouraged. Work currently underway, of

specific interest to Vegetation Diversity Project, which

would benefit from support include: (1) selection of

bluebunch wheatgrass and thickspike wheatgrass for

dry matter production during the establishment year;

(2) accession evaluations of bluebunch wheatgrass,

Snake River wheatgrass, thickspike wheatgrass, Basin

wildrye, beardless wildrye, and indian ricegrass; and

(3) accession collection trips to the Columbia Basin of

Washington for Snake River wheatgrass, bluebunch

wheatgrass, and indian ricegrass. Additional work of

interest to Vegetation Diversity Project would ‘focus on

collections and evaluations of accessions of squirreltail

and of forbs such as buckwheats, biscuitroots, and

globe mallows.

5. P3 - Determine the level of population hierarchy that is most useful for plant material

selection for revegetation/restoration.

Through a combination of common garden evaluations

and quantitative genetic data, a study to determine the

level of population hierarchy that is most useful for

plant material selection for restoration/reclamation

would be useful. The levels might be: populations

within communities, communities within watersheds,

watersheds within physiographic regions, and between

physiographic regions. Alternatively, an approach

might be to examine populations varying in distances

among several overlapping foci.

B. Problem Diaspores: Develop

techniques to enhance the establishment of native

species that are difficult to sow with standard

equipment.

1. P1 - Evaluate the various methods and technologies for sowing ‘problem' diaspores.

Diaspores are seed, fruits, fruits with attached structures, or even flowerheads or whole aerial plants with

several to many seeds dispersed as a reproductive

unit. Diaspores that are fluffy, hairy, awned or otherwise incompatible with standard drills, or that are

adapted to surface germination and require assisted

fixation to keep the seed in place, pose special problems in mechanized sowing. Several methods and

technologies are currently available for sowing ‘problem’ diaspores. Techniques that should be evaluated

include drills with metering devices that can handle

fluffy or appendaged seed; broadcasting combined

with land imprinting on loose or coarse soils; seedbed

treatments to disturb the soil before or after simple

broadcast seeding; broadcasting onto snowbanks;

hydroseeding; and fluid drilling (gel seeding). Evalua50

tion of the various techniques with species of interest to

the Vegetation Diversity Project would be very useful

as applied research and as a technology transfer tool.

Collaboration with the Intermountain Greenstripping

and Rehabilitation Project (BLM, Idaho State Off ice)

might facilitate accomplishment of this objective and

provide needed information for both projects. Species

of interest to Vegetation Diversity Project include

bluebunch wheatgrass, Snake River wheatgrass,

squirreltail, basin wildrye, Thurber’s needlegrass,

needle-and-thread, Indian ricegrass, various sagebrush species and subspecies, fourwing saltbush,

winter-fat, and possibly rabbitbrush species.

C. Seed Priming: Develop techniques to reduce the germination time for native

species.

1. P3 - Evaluate seed priming techniques to

enhance early germination of native species.

A considerable amount of seed priming work has been

done with Indian ricegrass and winterfat. Seed priming

techniques should be examined particularly for hardseeded forbs such as Lewis flax, globe mallows,

buckwheats, biscuitroots, and yarrow. Seed priming

may also prove useful for desirable perennial grasses,

in addition to Indian ricegrass, as an aid in concentrating germination and initial establishment and increase

site occupancy in areas where weed competition is

likely to be a problem. If seed priming can facilitate

initial site occupancy, breeding for uniform germination

may not be necessary and/or it might be possible to

shorten the length of period needed for weed control

without sacrificing natural variability of native species

germination. Evaluation of mechanical and chemical

scarification, temperature, and light effects on germination of desirable perennial species may provide

information useful in developing seed priming techniques. Species of immediate interest to the Vegetation Diversity Project include the grasses squirreltail,

bluebunch wheatgrass, Snake River wheatgrass, Idaho

fescue, Thurber’s needlegrass, needle-and-thread, and

basin wildrye.

V. Maintenance of

Desired Native

Vegetation

The ability to maintain lands that currently have, or are

restored to, a desired state of native plant diversity is
critical to long-term success of sustained multiple-use

of BLM lands. Restoration to and/or maintenance of

desired plant communities requires an understanding

of the nature of the dynamic equilibrium of desired

communities, factors influencing that equilibrium, and

conditions necessary to maintain desired levels of

selected plant species in a given plant community.

Many of the studies described below can be incorporated into studies identified in Competition and Establishment (Ill) and Plant Materials (IV) studies described

above.

A. Demography and Life

History: Descriptions of demography of the

important life stages of dominant desirable and

undesirable species.

1. P1 - Establish long-term permanent plots to

compare the demography of dominant desirable and undesirable species when grazed and

ungrazed and when grown in native-dominated

and exotic-dominated communities.

Three general studies would fall under this objective.

They include (a) seed longevity, (b) annual seedling

germination, establishment and survival, and (c) adult

survival and seed production. These studies will be

located near a long-term weather station so that

census information can be associated with precipitation

and temperature events.

(a) Seed Longevity: Examine the viability and

germinability of seeds buried (5-cm deep), of seeds in

litter at the soil surface, and in dry ambient conditions.

Replicated samples of shrub, forb and grass seeds will

be located in at least three field sites across the Great

Basin and Columbia Plateau. Seeds will be placed in

the field each year for the first five years. Seeds will be

extracted from the field annually. Germinability and

viability tests will be conducted to develop a timecourse for seed longevity for each species.

(b) Seedling Survival: Known numbers of

seeds will be distributed across the surface of plots on

an annual basis. Seedlings will be censused monthly

during the first year and annually in subsequent years

using standard mapping techniques (Mack and Pyke

1983). These studies would be compared among

years and among grazing treatments.

(c) Adult Survival and Seed Production: A

minimum of 200 adult individuals of each species will

be randomly selected and permanently tagged. The

fate of these individuals will be monitored annually.

Attempts will be made to determine the cause of death

for individuals that died during each year. Reproduction per individual will be estimated annually by determining seed counts on a subset of individuals

Results from these three studies will be used to

provide parameters for models to determine population

viability estimates for each species for the next 50

years with and without livestock grazing (e.g., Department of Energy sites such as the Idaho National

Engineering Lab).

B. Establishment of

Undesirable Species in

Desired Plant Communities:

Determine conditions for successful establishment

of exotics in a diverse native community.

1. P1 - Determine the roles of dispersal (or lack

thereof), localized disturbance, and livestock

grazing in regulating the spread of exotic

species into diverse native communities.

In areas where diverse native communities are established, known numbers of seeds of exotic weedy

species (e.g., medusahead, yellow star-thistle, other

knapweeds, etc.) will be intentionally sown across the

surface of permanent plots. Germination, survival,

growth, and reproduction will be monitored for each

individual in each plot. All plants of the weedy species

in the plot and around the plot would be removed

before the end of the growing season to reduce the

potential of the experiment introducing an exotic

species to a site. This study would be repeated over

several growing seasons to provide estimates of the

variance in germination and survival of these species.

At the same time, estimates of seed bank longevity

would be made for surface and buried seeds. These

seed bank longevity estimates and the germination,

survival, and reproduction estimates will be used to

determine the risk of population explosion using

population viability analyses (PVA).

Disturbances will be created in the upper 5 cm of the

soil profile on areas of .25 m2, or areas with existing

disturbance (e.g. ground squirrel occupation, ant hill

areas, wildlife or livestock trailing areas, etc.) will be

used. Plots similar to those described above will be

established. Similar plots will be established in undisturbed areas. Results of these treatments will be

compared to those of the controls using PVA.

51
C. Management for

Desirable Communities: Studies

are needed of management intervention techniques necessary or useful for maintenance of

desirable communities.

1. P1 - Evaluate an experimental expert system

for use of prescribed fire in big sagebrush

ecosystems. Determine the need for an additional expert system specifically designed for

use in big sagebrush ecosystems.

Prescribed fire can be a useful, effective tool for

regulating shrub dominance and for enhancing species

diversity in sagebrush ecosystems. An expert system

to help managers determine under what conditions

prescribed fire should be used to enhance diversity in

sagebrush ecosystems would be a useful technology

transfer program. Sufficient information exists to

evaluate an experimental expert system (Wright et al.

1992). Sources of information which could be used to

evaluate this experimental expert system for prescribed burning for use in sagebrush-steppe systems

include Schmisseur and Miller (1985), Champlin

(1983), Blaisdell (1953), Harniss and Murray (1973),

Wright et al. (1979), Wright and Bailey (1982), Bunting

et al. (1987), and Sapsis and Kauffman (1991). The

Fire Effects Information System (FEIS) would provide

additional information useful in evaluating the experimental expert system. FEIS is a computerized database type system designed to store and provide easy

user access to information regarding effects of fire on

plant species, plant communities, and associated

animal species (Fischer and Brown 1991). FEIS is not

an expert system, but it does provide a great deal of

information about fire effects on numerous plant

species occurring in semiarid western ecosystems, and

it would be very useful as an information base in

evaluating and/or developing an expert system. For

further information on use of FEIS contact the Boise

Interagency Fire Center at (208) 389-2676.

2. P3 - Evaluate season of livestock use for

compatibility with creating or maintaining.

desirable plant communities.

Timing and intensity of grazing influences the potential

for invasion of exotic weeds into diverse communities

of native perennials. Season of use has been implicated as an important variable in maintenance versus

degradation of desirable communities. Since grazing

is a dominant use on much BLM managed rangeland,

studies to evaluate different seasons of use on desired

plant communities are needed from a practical management perspective. Properly applied grazing/

browsing treatments may be compatible with maintenance of desired plant communities and should provide

a tool for creating or maintaining the necessary structure to support specific management objectives (such

as browse production for winter deer range, quality

forage for winter elk range, nesting cover, and forb

production). Treatments to be compared should

include deferred rotation grazing, fall-winter only use,

spring only use, summer only use, and no grazing.

The deferred-rotation treatment should include 3 or 4

pastures. Deferment periods should include late-winter

through early-spring and late-spring through summer.

The late-spring through summer period should encompass the apical meristem elevation stage of development through maturity for desirable, cool-season,

perennial grasses. Depending on number of pastures

and site conditions, fall through early-winter or independent fall and winter periods may be desirable.

Treatments need to be replicated at least twice (preferably more) and occur within the same community type

in the same relative desirable condition. Permanent

plots should be established within each treatment

pasture for the purpose of sampling shrub canopy

cover, herbaceous basal cover, and production of all

species. Plots will be measured at least twice a year.

Once in middle to late spring to monitor early season

forbs and grasses and once in early to middle summer

(end of growing season) for exotic annuals, perennial

grasses, forbs, and shrubs, including special status

plants. Feasibility of this study will be dependent on

locating suitable sites of sufficient size to include

replicated treatments.

VI. Special Status

Plants

Factors such as various land use activities (e.g.

reclamation/restoration efforts, livestock grazing, ATV

use, wildlife use, etc.), invasions of exotic plants,

invasions of juniper, changes in fire frequency, and

potential global warming may impact plant diversity

through extirpation of special status plants. Examinations of ecosystems and ecosystem processes responsible for the occurrence of these species is required for

their management and maintenance in the ecosystem.

Species selected for study should have a common

characteristic such as life form, seed dispersal mechanisms, germination requirements, or taxonomic relationship (e.g. genus, family). Currently, little documented information is available concerning these

factors for special status plants. We recommend that

the greatest effort be placed on compiling the available

data for plants on BLM lands. We strongly urge the

52
inclusion of special status plants in the experimental

designs of previously mentioned studies and of demonstrations, when appropriate.

A. Demographic Studies of

Special Status Plants: Collect

information on the demography of critical special

status plants and develop a data base for use in

population viability analyses.

1 . P1 - Coordinate studies of population status

and trend of selected special status plants

using population viability analyses.

Botanists at the state and district levels will be asked to

provide demographic data on critical populations. High

priority will be given to species with the potential of

establishment at additional sites and low priority given

to species that are edaphically restricted. Factors to be

considered in studies include: population structure (age

or stage), reproduction and establishment, timing and

frequency of measurement, and current trend of

weather, grazing, or competitors on selected special

status plants. These data will be used along with

modeling tools such as population viability analysis

(PVA) to determine the risk of extinction and to determine the stages of the population (e.g. seed production, seedbank longevity, seedling survival) in which

data collection is needed and on which management

should concentrate.

B. Special Status Plant

Restoration : Identify potential for restoration.

1. P3 - Identify potential for restoration of special

status plants.

Utilizing information from life history characteristic

studies above or information available from other

sources, evaluate methods for restoration of special

status plants on sites where they currently exist.

Evaluate seeding and transplanting methods, the need

for and methods of suppression of competition (e.g.

herbicides, livestock utilization, fire, etc.), and/or

changes in land management (e.g. grazing vs no

grazing, wildlife exclusion, exclusion of recreational

access, etc.) to facilitate the maintenance and spread

of special status species.

Life history and reestablishment information from

studies done at sites where a special status plant

population currently exists will be used to attempt

reestablishment on sites where it does not currently

exist, but has the potential to exist.

53
54

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67

Appendices
68

Blank page
Appendix A

Commercial Seed Sources

Commercial availability of native plant materials for use

in establishment of diverse native plant communities is

quite limited. Table A1 lists names, addresses and

phone numbers for four of the major seed companies

that market native seed for revegetating degraded

Great Basin and Columbia Plateau rangelands. Listing

of companies is for informational purposes only and

does not imply an endorsement by the BLM.

Table A2 provides a list of species and varieties of

native grass seed available from commercial sources.

The source of ecotype is provided for each variety

when identified in their respective catalogs. If source

of the ecotype becomes an important factor, then few

native seeds that are commercially available can be

traced to collections within the Intermountain West.

Only eight of the species for which the source of the

ecotype is identified, originated in the Intermountain

West. For one species, Cover sheep fescue, the

source population is Eurasian in origin.

The May 4, 1990 Final Draft of Research and Demonstration Program Plan to Restore and Maintain Native

Plant Diversity on Deteriorated Rangelands in the

Great Basin and Columbia Plateau contains lists-of

priority plants to restore plant diversity on target areas

in California, Idaho, Nevada, Oregon and Washington,

and Utah. Forb and shrub species included in those

lists which are commercially available are identified in

Tables A3 and A4, respectively. If variety and source

are provided by the companies, the information is

included.

Table A1. Seed companies offering native seed.

Company Name Address Telephone/FAX

Bitterroot Native Growers,

Inc.

445 Quast Lane

Corvallis, MT 59828

Davenport Seed Corporation P.O. Box 187

Davenport, WA 99122

Granite Seed 1697 West 2100 North

P.O. Box 177

Lehi, UT 84043

Sharp Bros. Seed Co. Box 140

Healy, KS 67850

(406) 961-4991/

(406) 961-4626

(509) 725-1235

(800) 828-8873/

(509) 725-7015

(801) 768-4422

(801) 531-1456/

(801) 768-3967

(316) 398-2231

(800) 4-NATIVE/

(316) 398-2220

69
Table A2. Species, varieties and commercial sources of native grass seed. For species

with two scientific names, the upper scientific name represents the Hitchcock (1971) taxonomy, while the lower name represents the Barkworth and Dewey (1985) classification of

the Triticeae.

Common name/

Latin name (Revised)+

Varieties

(Source of ecotype)

Company

Name

Thickspike wheatgrass/ Critana (Havre, MT)

Agropyron dasystachyum Davenport

(Elymus lanceolatus) Sharp

Beardless bluebunch wheatgrass/

Agropyron inerme

(Pseudoroegneria spicata subspp.

inermis)

Whitmar (Whitman

County, WA)*

Bluebunch wheatgrass/

Agropyron spicatum

(Pseudoroegneria spicata subspp.

spicata)

Secar (Lewiston, ID)*

Goldar (?)

Streambank wheatgrass/

Agropyron riparium

(Elymus lanceolatus)

Sodar (Grant County, OR)*

Western wheatgrass/

Agropyron smithii

(Pascopyrum smithii)

Arriba (Flagler, CO)

Barton (Barton County, KS)

Rosanna (Forsyth, MT)

Rodan (?)

Davenport

Slender wheatgrass/

Agropyron trachycaulum

(Elymus trachycaulus)

California brome/

Bromus carinatus

Rescuegrass

Bromus catharticus

Mountain brome/

Bromus marginatus

Granite

Granite

Davenport

Sharp

Flintlock (?)

Primar (Beebe, MT)

San Luis (Rio Grand County,

Co)

Pryor (Pryor Mtns., MT)

Revenue (Saskatchewan,

Canada)

Cucamonga (?)

Prairie (?)

Bromar (Pullman, WA)*

Granite

Davenport

Sharp

Davenport

Granite

Davenport

Sharp

Granite

Davenport

Sharp

Sharp

Sharp

Granite

Davenport

Sharp

Granite

Davenport

Sharp

Davenport

Davenport

Granite

Davenport

Inland saltgrass/

Distichlis stricta

Granite

Davenport

70
Table A2. Species, varieties and commercial sources of native grass seed. For species

with two scientific names, the upper scientific name represents the Hitchcock (1971) taxonomy, while the lower name represents the Barkworth and Dewey (1985) classification of

the Triticeae. (continued)

Common name/

Latin name (Revised)+

Varieties

(Source of ecotype)

Company

Name

Canada wildrye/

Elymus canadensis

Great Basin wildrye/ Magnar (Saskatchewan,

Elymus cinereus Canada)

(Leymus cinereus) Arrowhead (?)

Creeping (or Beardless) wildrye/

Elymus triticoides

(Leymus triticoides)

Idaho fescue/

Festuca idahoensis

Sheep fescue/

Festuca ovina

Prairie junegrass/

Koeleria cristata

Indian ricegrass/

Oryzopsis hymenoides

Reed canarygrass/

Phalaris arundinacea

Alkali bullrush/

Phragmites communis

Alpine bluegrass/

Poa alpinum

Big bluegrass/

Poa ampla

Canby bluegrass/

Poa canbyi

Shoshone (Riverton, WY)

Joseph (Idaho)*

Covar (Turkey)

Nezpar (Whitebird, ID)*

Paloma (Pueblo, CO)

Loreed (?)

Vantage (?)

Loreed (?)

Palaton (?)

Venture (?)

Sherman (Sherman County,

OR)*

(Canbar (Blue Mtns., WA)*

Granite

Davenport

Sharp

Granite

Davenport

Davenport

Granite

Davenport

Davenport

Granite

Granite

Davenport

Granite

Davenport

Granite

Davenport

Sharp

Granite

Davenport

Sharp

Granite

Davenport

Granite

Davenport

Granite

Davenport

Sharp

Granite

Davenport

Sharp

71
Table A2. Species, varieties and commercial sources of native grass seed. For species

with two scientific names, the upper scientific name represents the Hitchcock (1971) taxonomy, while the lower name represents the Barkworth and Dewey (1985) classification of

the Triticeae. (continued)

Common name/ Varieties

Latin name (Revised)+ (Source of ecotype)

Company

Name

Sandberg bluegrass/

Poa sandbergii

Sharp

Alkaligrass/

Puccinellia distans

Bottlebrush squirreltail/

Sitanion hystrix

(Elymus elymoides)

Fults (?)

Sand dropseed/

Sporobolus cryptandrus

Salado (?)

Saltalk (?)

Columbia needlegrass/

Stipa columbiana

(Stipa nelsonii)

Needle and thread/

Stipa comata

Letterman needlegrass/

Stipa lettermani

Elk sedge/

Carex geyeri

Granite

Davenport

Davenport

Granite

Davenport

Granite

Sharp

Davenport

Granite

Davenport

Granite

Davenport

Granite

Davenport

Bitteroot

+Revised nomenclature based on Barkworth and Dewey (1985) Genomically based genera in the perennial Triticeae of North America: Identification and

membership. Amer. J. Bot 72(5):767-776.

*Source of ecotype is from the Intermountain West.

72
Table A3. Commercially available forb species with potential for use in restoring plant

diversity in Great Basin and Columbia Plateau rangelands.

Latin name (variety & source if

provided)/

Common name

State for which

listed +

Company

Achillea millefolium/ Idaho

White Yarrow Oregon & Wash

California

Nevada

Oregon & Wash.

Idaho

Granite

Granite

Bitterroot

Balsamorhiza sagittata/

Arrowleaf balsam

Epilobium angustifoliuml Granite

Fireflower

Granite

Bitterroot

Granite

California

Oregon & Wash.

Idaho

Eriogonum umbelatum/

Sulfur flower

Hedysarum boreale/

Northern sweetvetch

Helianthus annuusl California Granite

Annual sunflower

Linum lewisii (Appar, Black Hills, Granite

SD)/

Blue (Lewis) flax

Idaho

Nevada

Oregon & Wash.

Utah

Lupinus arizonicus/ Idaho Granite

Desert lupine

Lupinus caudatusl Idaho Granite

Tailcup lupine

Lupinus perennis/ Idaho Granite

Wild lupine

Granite

Bitterroot

Granite

Lupinus sericeusl Idaho

Silky lupine

Lupinus succulentus/

Arroyo lupine

Idaho

Granite

Bitterroot

Bitterroot

Penstemon cyananthusl Idaho

Wasatch penstemon

Penstemon deustusl Idaho

Hotrock penstemon

Granite

Bitterroot

Idaho

Oregon & Wash.

Penstemon eatonitii/

Firecracker penstemon

73
Table A3. Commercially available forb species with potential for use in restoring plant

diversity in Great Basin and Columbia Plateau rangelands. (continued)

Latin name (variety & source if

provided)/

Common name

State for which

listed +

Company

Penstemon fruticosusl

Shrubby penstemon

Idaho Bitterroot

Penstemon palmeri (Cedar)/

Palmer penstemon

Idaho

Oregon & Wash.

Granite

Bitterroot

Sphaeralcea coccinea/

Scarlet globemallow

Idaho

Nevada

Utah

Granite

Sphaeralcea grossulariaefolia/

Gooseberry leaf globemallow

Idaho

Utah

Granite

+Each state involved in the Vegetation Diversity Project identified priority plant species which were listed in: Vegetation Diversity Project: A Research and

Demonstration Program Plan, May 1990, USDI-BLM, Oregon State Office.

Table A.4. Commercially available shrub species with potential for use in restoring plant

diversity in Great Basin and Columbia Plateau rangelands.

Latin name/

Common name

State for which

listed +

Company

Amelanchier alnifolia/

Serviceberry

Artemisia canal

Silver sagebrush

Artemisia nava/

Black sagebrush

Artemisia tridentata/

Basin big sagebrush

Artemisia tridentata vaseyana/

Mountain big sagebrush

California

Idaho

Idaho

Idaho Granite

Nevada Bitterroot

Oregon & Wash. Davenport

Idaho

Oregon & Wash.

Granite

Bitterroot

Davenport

Granite

Bitterroot

Davenport

Granite

Bitterroot

Davenport

Granite

Bitterroot

Davenport

74
Table A.4. Commercially available shrub species with potential for use in restoring plant

diversity in Great Basin and Columbia Plateau rangelands. (continued)

Latin name/ State for which

Common name listed +

Artemisia tridentata wyomingensisl Idaho

Wyoming big sagebrush Nevada

Company

Granite

Bitterroot

Davenport

Atriplex canescensl

Fourwing saltbush

California

Idaho

Nevada

Oregon & Wash.

Utah

Granite

Davenport

A triplex con fertifolia/

Shadscale

Idaho

Nevada

Utah

Granite

Bitterroot

Davenport

A triplex triden ta ta/

Trident saltbush

Idaho

Davenport

Granite

Ceratoides (Eurotia) lana ta/

Winterfat or White sage

California

Idaho

Oregon & Wash.

Utah

Granite

Davenport

Cercocarpus ledifolius/

Curl-leaf mountain mahogany

Chrysothamnus nauseosus/

Rubber rabbitbrush

Chrysothamnus visicidiflorus/

Douglas rabbitbrush

Purshia tridentata/

Antelope bitterbrush

Ribes aureum/

Golden currant

Shepherdia argentea/

Silver buff aloberry

California

Oregon & Wash.

Idaho

California

Idaho

California

Idaho

Nevada

Oregon & Wash.

California

California

Granite

Bitterroot

Davenport

Granite

Bitterroot

Davenport

Granite

Davenport

Granite

Bitterroot

Davenport

Granite

Bitterroot

Davenport

Granite

Bitterroot

Davenport

Symphoricarpos albus/

Common snowberry

California Granite

Bitterroot

Davenport

+Each state involved in the Vegetation Diversity Project identified priority plant species which were listed in: Vegetation Diversity Project: A Research and

Demonstration Program Plan, May 1990, USDI-BLM, Oregon State Office.
76

Blank page
Appendix B

Cultural Practices

Wasser (1982) provides planting depth, rate, time, and

related information for several of the priority species

listed in the May 1990 Vegetation Diversity Project: A

Research and Demonstration Program Plan. Available

information is listed below.

Grasses

Agropyron dasystachyum (Elymus lanceolatus)

Thickspike wheatgrass:

Drill seed 1/2 inch deep on fine-textured soils and up to

1 inch deep on coarser soils. Firming seedbeds before

seeding is beneficial. Cover broadcasted seed shallowly with soil. Supplemental mulch and light irrigation

on erosive and droughty sites ensure better establishment. About 20 to 25 PLS per square foot usually

needed to obtain 1 to 2 plants per square foot. Fewer

seeds with rhizomatous species may suffice if erosion

and weed infestations are not serious hazards during

longer establishment periods. Five to ten pounds PLS

per acre are used for rangeland areas. Rate should be

increased 100 percent for broadcasting with this

species. About 50 PLS per foot of row were used in

tests on surface-disturbed lands in western Colorado;

similar amounts were used for harsh sites and south

and west exposures. Drill seed either in early spring,

late fall, or late summer-early fall (Aug.-Sept.) with

ample moisture. Usually seed prior to the 2-month

period with the most favorable moisture and temperature conditions for seedling establishment.

Agropyron smithii (Pascopyrum smithii) Western

wheatgrass

Drill seed 1/2 to 1 inch deep on fine and mediumtextured soils, respectively. Cover broadcasted seed

shallowly with soil. Supplemental mulching and light

irrigating aid stand establishment on arid, droughty,

and erosive sites. About 20 to 25 PLS per unit area

needed as seeding rate to establish one plant per unit

area under moderately favorable nonirrigated conditions. Recommended drill seeding rates: 5 to 15

pounds PLS per acre for semiarid to subhumid areas.

Increase rates 50 to 100 percent for broadcasting,

quicker and denser cover, or for harsher south and

west-facing sites. Seed before or very early in the 2-

month period having the most favorable conditions for

rapid germination and seedling growth: early spring,

late fall; late summer to early fall (Aug. or Sept.); or

June 15 to July 15 (only in Southwestern pine and

pinyon-juniper zones).

Agropyron spicatum (Pseudoroegneria spicata)

Bluebunch wheatgrass

Drill seed 1/4 inch, 1/2 inch, and 3/4 inch deep on

clayey, loamy, and sandy soils, respectively. Cover

broadcasted seed with soil to similar depths. Drill

seeding rates vary from 5 to 10 pounds PLS per acre

for rangeland revegetation purposes. Fifty to 100

percent more seed should be used for broadcasting

and for harsh and south and west-facing sites. Seed

before or very early in the 2-month period most favorable for seedling establishment; usually either early

spring or late fall, but also possible in early fall (during

August and Sept.) in areas with good fall moisture or

on summer-fallowed fields.

Bromus marginatus Mountain brome

Drill seed about 1/2, 1, or 1 1/2 inches deep on finer,

medium or coarse textured soils. Commonly seeded at

8 to 12 pounds PLS per acre for rangeland purposes;

rate may be increased on disturbed soils and on harsh

or eroding surfaces. Supplemental mulch aids soil

stabilization and stand establishment on steep and

erosive sites. Seed in late fall or as early in summer as

possible in higher mountains.

Elymus cinereus (Leymus cinereus) Great Basin

wildrye

Seed at 1 inch depth, drill seed 20 PLS per square foot

(5 pounds PLS per acre) for dense pasture swards or

use half as much seed when drilled early spring in

furrows or corrugations on spring-flooded sites. Seed

late fall or as early as possible in summer in mountain

sites.

Festuca idahoensis Idaho fescue

Seed 1/4, 1/2, or 3/4 inches deep on fine, medium, or

coarse-textured soils, respectively. Better stands

obtained on prefirmed seedbeds. Drill a minimum of

15 to 25 PLS per square foot (2 to 3 pounds PLS per

acre) for minimal satisfactory stands on rangelands.

Increase rate 50 to 100 percent for harsh sites; south,

west, or steep exposures; poorer seedbeds; and when

broadcasting. May be seeded directly in nonvolunteering grain stubble or in alternate rows with wheat or
rye; supplemental mulch may be added for steep

slopes and highly erosive sites. Seeding time varies

regionally and altitudinally: early spring at lower

altitudes with reliable moisture; late fall with uncertain

moisture and at lower mountain elevations; or in spring

or very early summer, as early as possible, at higher

mountain elevations.

pasturage and cover. Increase seeding rates 50 to

100 percent for broadcasting; for harsher, drier, and

erosive sites; and for quicker and denser cover. Seed

before or very early during the 2-month period with

most favorable conditions for rapid germination and

seedling growth: early spring; late summer; late fall; or

as early as possible in summer for higher mountain

sites.

Hilaria jamesii Galleta

Poa sandbergii (Poa secunda) Sandberg bluegrass

Drill seed, in special drill equipped to handle chaffy

seed, at 1/2 inch depth on fine-textured soils and

moister seedbeds and up to 1 inch deep on coarser

soils and drier seedbeds. May broadcast seed, but

cover with soil to similar depths. Seeding in furrows,

basins, and pits and using deep furrow type drills

contribute to better stand establishment on more arid

and finer textured seedbeds. Supplemental mulching

plus light irrigations is the most reliable method of

obtaining satisfactory stands. Plant 20 to 30 PLS per

square foot for rangelands stands or 40 to 60 PLS per

linear foot of row for disturbed land stabilization. Plant

before or early in a 2-month period with most favorable

conditions for rapid germination and seedling establishment; often June 15 to July 15 in northern Arizona and

New Mexico.

Oryzopsis hymenoides Indian ricegrass

Drill seed 1 1/2 to 3 inches deep on medium to coarsetextured soils. Seeds emerge well from 4 inch depths

in sand. Similar soil coverings needed for broadcast

seedlings. Drill 20 to 25 PLS per square foot for

rangeland purposes; double the seeding rate when

broadcasting and for critical area stabilization purposes. Seed into nonvolunteering crop stubble seeded

in 18-inch drill rows or closer in semiarid or winderosion areas. Still higher rates of seeding, supplemental mulching, and light irrigation may be necessary

for good soil stabilization of disturbed sites. Generally

seed before the 2-month period with most favorable

conditions for rapid germination and seeding growth:

late fall with high dormancy seed; early spring, early

fall, or June 15 to July 15, according to regionally

reliable moisture, with low dormancy seed. Dormancy

overcome by using older seed, acid-bleached seed, or

planting seed in fall to overwinter in soil.

Poa amp/a Big bluegrass

Drill seed about 1/2 inch deep for medium-textured

soils with average moisture conditions or 1/4 inch

shallower or deeper for finer and moister or for coarser

and drier soils, respectively. Cover broadcasted seed

with soil to a similar depth. Drill 3 to 5 pounds PLS per

acre for minimal to moderate stand densities on

semiarid to average moisture range sites seeded for

Drill seed on well-prepared and firmed seedbeds at 1/4

to 1/2 inch depths. Drill 30 to 40 PLS per square foot

for rangeland purposes. Double seeding rate when

broadcasting; for harsh, dry, and erosive sites; and for

higher density cover. Seed areas before the 2-month

period most favorable for rapid germination and

seedling growth. Late fall suggested for Pacific

Northwest and Great Basin states.

Forbs

Achillea millefolium Common (White) yarrow

Drill about 1/4 inch deep, or broadcast and cover to

similar depth with soil, or cultipack. Drill 40 to 60 PLS

per square foot (1/2 pounds PLS per acre) for pure

stands under ideal moisture and soil conditions; double

the rate when broadcasting and for harsh, erosive, and

south- or west-facing sites. Reduce rate to proportion

desired in mixtures. Seed at optimum date for primary

species when in mixtures; preferably before the

moistest growing season; usually early spring, late

summer, or late fall. Species can be transplanted by

sodpieces for critical area stabilization, such as gullies.

Balsamorhiza sagittata Arrowleaf Balsamroot

Drill seed 1/2 to 1 inch deep on medium and coarsetextured soils, respectively; vary depths similarly for

moist and drier soil condition, respectively. Drill in

either desired or original species composition percentages of a full stand rate of 20 PLS per square foot (10

to 20 percent recommended), using seed subjected to

2 months cold-moist stratification where 3 months

continuous snow cover not assured on site after late

fall seedings. These stratified seeds can be seeded

very early, or as early as possible, in spring.

Hedysarum boreale Northern sweetvetch

Drill seed 1/2 inch deep on loam soils, up to 3/4 inch

deep in drier and coarser soils, and 1/4 inch deep on

finer textured and moister soils. Rates of 1/2 pound

per acre drilled or 1 pound per acre broadcasted are

78
recommended in seeding mixtures for sandy aspects

of mountain brushlands in Utah. Planting in early

spring or late fall advocated, late fall planting provides

natural stratification. Inoculate seed with specific

Rhizobium strain for nitrogen-fixation just before

planting. Plants experimentally stimulated in soil

infested with Glomus fasciculatus, a mycorrhizal

symbiont.

Linum lewisii Lewis flax

Plant seed 1/4 to 3/4 inch deep or broadcast and cover

with soil to similar depth. Adapt seeding rate to desired

composition in seeding mixture, usually no more than 5

to 10 percent of a full stand seeding rate of 20 to 30

PLS per square foot (about 3 to 4 pounds PLS per

acre) for semiarid zones. Increase rates 50 to 100

percent for humid zones, broadcasting, and for harsh

sites, especially those on erosive soils, steep slopes,

and south and west exposures. Plant at time optimal

for primary species in seeding mixtures, preferably

before the most humid growing season. Plant the

species alone either late fall of seed-harvest year, the

following spring, or the second fall; tests indicate latter

date results in greater emergence.

Sphaeralcea grossulariaefolia Gooseberry

globemallow

Plant seed less than 1 inch deep, varying with soil

texture, moisture, and firmness and quality of seedbed.

Plant only about 10 percent of this species in seeding

mixtures or use about 1/4 pound PLS per acre. Fall

and winter planting dates preferred to take advantage

of late winter-early spring moisture and to provide a

prechilling seed treatment.

Artemisia cana Silver sagebrush

Plant seed on the surface or very shallowly; better

germination reported with light and at temperatures

between 50° and 86°F. Plant 10 to 20 PLS per square

foot (0.5 to 1.0 pound PLS per acre) for full stands.

Species often seeded at reduced rates approximating

original composition on sites; e.g., using 0.10 pound

PLS per acre. Rates should be doubled or further

increased for critical areas, steep slopes, and eroding

surfaces. Because of tolerance to broad temperature

range for germination, amenable to seeding almost any

time of the year when there is adequate surface soil

moisture, such as fall, early spring, spring, or summer.

Hardwood cuttings, cultured in greenhouse and

hardened before out-planting on surface mined soils,

gave better stands and survival than direct seeding in

Wyoming-Colorado investigations and were more

tolerant than other species to wildlife browsing.

Artemisia nova Black sagebrush

Plant achenes 1/4 inch deep. About 100 PLS per

square foot used in nurseries to obtain about 50

seedlings per square foot in optimizing limited space

and intensive culture; 1 to 2 PLS per square foot

should prove an adequate rate on rangelands under

ideal growing conditions. Comparing planting site

conditions and survival expectancy with that ideal

standard suggests that 10 to 20 PLS per square foot

(1/2 to 1 pound PLS per acre) might be adequate drill

rates for full stands on average rangeland sites.

Higher rates needed when broadcasting and when

seeding severe, erosive, and critical sites. Species

more commonly used as minor element in seed

mixtures for range revegetation, partly due to limited

seed supply. Plant either in late fall and winter or use

seed pretreated to enhance germination (i.e. placed in

moist blotters at 32° to 38°F for 10 days) in spring.

Amelanchier alnifolia Saskatoon serviceberry Artemisia tridentata Big sagebrush

Plant seeds 1/4 inch deep. Nurserymen seed this

species at a rate of 25 PLS per foot of row. Reduce

seeding rate to obtain desired or original composition

on sites being restored or improved. Only 1/2 to 1

pound per acre recommended in game range restoration mixtures. Plant unstratified seed in late fall and

moist prechilled seed in spring. Transplants or container stock should be planted as early as possible in

spring. Moist soil, mulch, and partial shade enhance

nursery propagation. Readily propagated in greenhouse from softwood and root cuttings; stands can be

established by transplanting seedlings or nursery

stock. Using older nursery stock may be advantageous on difficult sites. Bare-rooted stock survived

better than container stock in pine zone in South

Dakota.

Either broadcast seed on the surface or plant at very

shallow depth of about 1/4 inch. Light favors germination of basin-form, and seed will not emerge from 1

inch depths. Limited benefit of light noted with other

two subspecies. One-forth to 1/2 pound per acre or

double these rates recommended for drilling and

broadcasting seed in mixtures on sagebrush-adapted

but depleted Utah game ranges. Plant either in spring,

fall, or winter. Moist chilling seed treatment may be of

benefit when planting the spring after seed harvest.

Atriplex canescens Fourwing saltbush

Plant seed 1/2 to 3/4 inch deep in well-prepared

seedbeds; use shallower depth with moist and finer

79
textured soils; use the deeper placement for dry, loose,

and coarse-textured soils. Mulching usually improves

seedling emergence and survival. Seed 4 to 8 pounds

per acre of dewinged seed and 8 to 15 pounds of

winged seed for pure stands in favorable to less

favorable habitats or site conditions and when planting

or broadcasting, respectively. Reduce rate to desired

or original fraction of the cover on planting sites when

seeding in mixtures; 1/2 to 5 pounds per acre rates

used as a component in 10 to 30 pounds per acre total

seedings in Utah game range restorations, the higher

rates in blackbrush type and when broadcasting, 1/2 to

2 pounds per acre rates more commonly used on

shadscale saltbush, black greasewood, big sagebrush,

mountain brush, and juniper-pinyon types. Spring or

midsummer seedings generally more successful than

fall seedings in the Southwest. Often seeded in

mixtures sown in late fall or winter in Utah. Transplanting is an effective method of establishing stands on

small critical areas. Transplanting is done in spring,

with damp soil conditions, either by hand in prepared

seedbed or in water-concentrating furrows or basins, or

by using scalper and transplanter, carefully hand-fed,

keeping stock moist and avoiding “J-roots”.

Ceratoides (Eurotia) lanata Winterfat (White sage)

Plant seed less than 1/2 inch deep. They can be

broadcast on surface of saturated soils, but usually

better results obtained by planting 1/16 to 1/4 inch

deep and covering or pressing broadcasted seed in

soil to similar depths. Firming seedbed below seed

depth improves emergence, and mulch aids natural

establishment. Species usually only planted in mixtures with rates of 1/2to 1 1/2 pounds per acre drilled

or 1 1/2 to 3 pounds per acre broadcasted in total seed

mixes of 10 to 20 pounds per acre. Recommend trying

15 to 20 PLS per square foot (about 5 to 7 pounds PLS

per acre) drill rates for full stands; however, usually

advantageous to seed with vigorous adapted grasses

where annual weeds, such as cheatgrass brome

(Bromus tectorum) and halogeton (Halogeton

glomeratus), threaten. Best season of planting unknown; late fall, winter, and spring seedings used or

recommended; usually better to seed before the

moistest growing season, provided surface soils not

saturated more than week or two. Some propagating

success reported using stem cuttings in Nevada;

practice probably useful for propagating superior

selections.

Chysothamnus nauseosus Rubber rabbitbrush

Best planting depth unknown; use gardener’s rule of 2

to 4 times the largest seed diameter, or about 1/2 to 1

inch deep. On game ranges direct seedings are made

in fall or winter in Utah, and roadside seedings are

made in November in Nevada. Since natural germination occurs from March to June, pretreating the seed

(store wet for 1 month at 39°F to enhance germination)

and seeding early in March may be a safer seeding

time. No critical tests of optimum seeding rates appear

in print. Rates of 1/2 pound per acre (drilled) and 1

pound per acre (broadcasted) are used in complex

game range revegetation mixtures. Good stands were

reported from transplanting 3 to 5-month old seedlings

in early spring in Utah and some establishment success was reported with aerial seeding.

Chysothamnus viscidiflorus Douglas rabbitbrush

Plant seed about 1/4 inch deep or two to four times

seed diameter. Best rate of seeding and optimal depth

not known. Rabbitbrush was drilled at 1/4 pound per

acre and broadcasted at 1/2 pound per acre in complex game range seeding mixtures in Utah. Game

range seedings are made in late fall and winter.

Germination studies indicate it can be seeded “anytime

after harvest through the second fall with good germination results”. Good success from transplanting

seedlings or wildings were reported from Utah.

Purshia tridentata Antelope bitterbrush

Drill seed in a clean, firm seedbed with a rangeland drill

about 1 inch deep, adapt depth slightly deeper or

shallower according to moisture, texture, and seedbed

firmness. Cover broadcasted seed with soil to similar

depth. Optimal rates for pure seedings apparently not

critically tested, probably because most seedings are

made in mixtures to avoid waiting 5 to 10 years for

bitterbrush to develop usable forage supplies. Rates of

1/2 to 1 pound per acre, 1 to 2 pounds per acre, and 2

to 3 pounds per acre, drilled and broadcasted, are

prescribed in game range restoration in Utah. Seed

are planted most commonly in late fall or early winter to

accomplish a natural stratification over winter but

treated seed can be planted in spring or later with

adequate moisture. Limited transplanting of nursery

grown seedlings or container stock has been done,

usually in spring.

Ribes aureum Golden currant

Nursery seedlings are made 1/8 to 1/4 inch deep and

mulched; rangeland seedings might be made at 1/2

inch depth in drier sites with better survival expected.

Nurserymen seed at rate of 40 PLS per linear foot of

row. Best rate on rangelands is not documented.

Many seedings optionally include currant seed as

minor component, perhaps at 1/2 to 1 pound per acre,

in range seedings for game range restoration or

controlling erosion. Fall preferred seeding time;

stratified seed can be sown in spring. Areas also

80
revegetated using nursery or container stock and

rooted cuttings.

Shepherdia argentea Silver buffaloberry

In nursery practice, seeds are planted 1/4 inch deep

and covered with up to 1 inch of mulch. This suggests

that seed could be planted at depths up to 3/4 inch in

coarse, dry, and loose soil (in fall under wildland

conditions). About 50 percent seedling establishment

is expected in nurseries while 5 to 15 percent establishment would be good survival from seeding under

dryland field conditions. This species is used as a

minor addition to game rangeland revegetation mixtures in Utah at unspecified rates. Similar species are

added at 1 to 2 pounds per acre rates in total seeding

mixtures of 10 to 30 pounds per acre. Seed can be

sown in the fall or can be moist-prechilled (“stratified”)

for 3 months then sown in spring or later where late

summer moisture is more reliable or where irrigation is

available. Buffaloberry can be transplanted by digging

root sprouts from wildings or from nursery-grown stock.

Older stock is often used for landscaping; 2-year-old

planting stock is used in reclaiming eastern coal

minesoils.

81
82

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Appendix C

Seed Testing

The Seed Laboratory of the Crop and Soil Science

Department at Oregon State University is able to

provide seed testing service. In addition to the traditional seed potential tests of purity and germination

potential, the Seed Lab provides the following tests:

a) Tetrazolium - A chemical test indicating seed

viability by a staining process. Results are available as

quickly as 24 hours.

b) X-ray - Empty, insect infested, and internal and

external mechanical injury are some of the abnormalities evident by means of a radiograph (X-ray film).

c) Chromosome count - With the growing of polyploids,

it becomes necessary to determine variety contamination by counting the number of chromosomes.

d) Moisture - High moisture and high temperatures are

detrimental to seed viability. For storage (refer to

Appendix D- Seed Storage) and shipping, it becomes

important to know that the moisture content of the seed

is at a safe level.

e) Seed Weight - Where space planting or high-cost

seed is being used, it becomes desirable to know the

weight per 1,000 seeds so that density of planting can

be controlled.

f) Variety - Chemical and physical test for varieties are

available to help maintain a high varietal purity level.

g) Endophyte - This staining process detects the

presence of endophytic fungi in seed, seedling, and

plant material.

At the minimum, purity and germination potential

should be tested. Other testing will depend on specific

circumstances.

83
84

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Appendix D

Seed Storage

One of the goals of the Vegetation Diversity Project is

to develop an information base which will improve

BLM’s ability to re-establish and manage for native

vegetation. Addressing this goal will require collection

of native plant seeds from natural stands to provide

plant materials necessary for research purposes.

Since many species seldom produce viable seed,

relatively long-term (two years or longer) storage of

collections will be critical for maintaining seed stocks of

native seeds for research purposes and for potential

expansion.

Principles and Practices of Seed Storage by Justice

and Bass (1978) provides a comprehensive coverage

of seed storage. Storage temperature and seed

moisture content are the most important factors

affecting seed longevity, with seed moisture content

usually more influential than temperature.

Research needs and time and labor constraints likely

to affect the Vegetation Diversity Project dictate the

probable need for long-term storage of seeds already

collected by the Rangeland Resources Department

and those which will presumably be collected throughout the duration of the project. Refrigerated, dehumidified storage is best suited for long-term holding of

seeds. Under humidity conditions common to Corvallis

through the winter months, controlled atmospheric

storage conditions or sealed storage will be necessary

to maintain seed viability. For safe, sealed storage for

up to 3 to 5 years at ambient temperatures, seeds

must be dried to between 5 and 8 percent moisture

content before they are sealed in moistureproof

containers. For longer storage, the moisture content

must be reduced to between 2.5 and 5 percent before

packaging (Justice and Bass 1978).

85
86

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Appendix E

Seed Treatment Studies

Indian ricegrass

Indian ricegrass seed is characterized by physiological

and mechanical dormancy, but their relative importance is a characteristic of the seedlot rather than of

the species as a whole. Seed age, genotype, and seed

production and storage environments are important

factors that affect dormancy among seedlots (Jones

and Nielson 1992). The following excerpts of the

literature review in the Jones and Nielson (1992) paper

describe current knowledge of Indian ricegrass seed

dormancy:

“Seed dormancy is an important cause of the poor

stand establishment that has limited use of Indian

ricegrass. Mechanical dormancy, resulting from

the exclusion of 0, by the indurate lemma and

palea (Toole 1940) is more persistent than

physiological dormancy (McDonald 1976). Physiological dormancy decreases over time, but

storage at low humidity and temperature slows the

process (Robertson 1976, McDonald and Khan

1977). Physiological dormancy is of less concern

when fall seeding is practiced, as is common in the

Intermountain region, because it can be broken by

cool, moist field conditions (Stevens and Meyer

1990). ...Physiological dormancy has been reduced by aging seed (Rogler 1960), fall planting

(Fendall 1966), prechilling (Toole 1940, Clark and

Bass 1970), and application of growth regulators

such as kinetin and gibberellic acid (Clark and

Bass 1970, McDonald 1976, Young et al. 1985).

Mechanical dormancy has been reduced by

mechanical and acid scarification, but scarification

increases germination at the expense of seed

quality. Early workers (Stoddart and Wilkinson

1938) eliminated mechanical dormancy by manually dissecting the lemma and palea, but more

recently mechanical scarification has been employed .”

“Extensive research has been conducted on

acid scarification (Stoddart and Wilkinson 1938,

Plummer and Frischknecht 1952, McDonald 1976,

Young et al. 1985). Seed damage during acid

scarification can probably be reduced by adjusting

length of treatment to seed size (Stoddart and

Wilkinson 1938) or to lemma thickness (Zemetra

and Cuany 1984).”

“While germination of naked seed is considerably higher than seed with lemma and palea intact

(Young and Evans 1984, Jones et al. 1988) naked

seed are susceptible to fungal and bacterial

disease. The disease resistance conferred by the

lemma and palea has been attributed to phenolic

compounds. McDonald (1976) successfully

controlled disease in the laboratory with 40%

maneb (manganese ethylenebisdithiocarbonate)

applied as a dust or slurry. Poor field establishment of acid-scarified seed despite dusting was

attributed to deterioration of the lemma and palea

over winter (Zemetra et al. 1983). Lemmas and

paleas of intact mechanically scarified seed may

be more persistent over winter than those of acidscarified seed. This suggests a possible advantage

of mechanical over acid scarification for field

establishment. . . . Toole (1940) concluded acid

scarification reduced physiological dormancy as

well as mechanical dormancy because some

scarified seedlots exhibited enhanced germination

despite persistent lemmas and paleas. Griffith and

Booth (1988) suggested loss of dormancy in

recently harvested seed could be accelerated by

scarification before storage. Shaw (1976) found

that prechilling more effectively broke dormancy of

naked seed than intact seed. These results

suggest that breaking mechanical dormancy may

accelerate the loss of physiological dormancy.”

Winterfat (White sage)

Booth and Schuman (1983) conducted a series of

studies to compare winter-fat establishment from whole

fruits and from seed. Their studies demonstrated three

important ways the whole fruit aids seedling establishment. First, the hairs of the bracts become embedded

in the soil surface and restrain the fruit, thereby improving radicle penetration of the soil. Second, threshed

seeds have been shown to have a significant population (up to 24%) of germinants which lack a positive

geotropic response by the radicle. The geotropic

deficiency found in threshed seed is apparently due to

damage to the embryo rootcap during threshing. Third,

a comparison of seedling vigor, as measured by radicle

elongation of seedlings established from fruits and

from seed, found radicle growth from fruits to be almost

twice that of seedlings from seeds. The authors made

the following recommendations for improving the

planting success of winterfat:

1. Use good, large, healthy appearing fruits (and not

threshed seed) which have been allowed to

87
afterripen at room temperature for 2 months before

storage in a cold (0 to 4°C, 32 to 39°F), dry environment.

2. Broadcast the whole fruits. The seedbed must be

rough, providing numerous places for the fruits to

lodge - otherwise most of the fruits will be blown off

the area being planted. In some instances a

broadcast seeder, such as a Brillion Seeder, may

effectively plant winterfat fruits at the required

shallow (6.4 mm - 1/4 inch or less) depth.

3. If planting in an area of winter precipitation, plant

as late in the fall as possible. A snow cover soon

after planting will further reduce the amount of fruit

lost due to the wind.

4. If working in an area which is likely to have a dry

surface soil during winter, plant in the spring when

the probability is greatest of having extended

periods of soil moisture between field capacity and

saturation. Also keep in mind that the larger the

young plants are when hot weather 20 to 27°C (70

to 80°F) arrives, the better the survival.

5. A spring planting of fruits soaked for 48 hours at

0°C (32°F) followed by hand planting in moist soil,

can be recommended as a technique to enhance

establishment of a few plants which may serve as

sources of fruits for later natural revegetation or as

special area plantings. The soaked fruits must not

dry before germination occurs.

In a later study, Booth (1992) concluded that imbibition

temperature affects post-germination growth of

winterfat. Successful germination, establishment,

and survival of winterfat are better at 5°C compared to 15-20°C. Therefore, winterfat should be

sown during those parts of the year when diaspores will imbibe at cool temperatures.

Winterfat should be imbibed and held at 5°C for 4

days, then germinated at 15°C when testing

germination.

88
Appendix F

Noxious Weeds

Table F1. Idaho Department of Agriculture Designated Noxious Weeds.

Common Name Latin name

Austrian field cress

Austrian pea weed or Swainsonpea

Buffalo bur

Camelthorn

Canada thistle

common crupina

Dalmation toad flax

diffuse knapweed

Dyers woad

field bindweed

henbane

jointed goatgrass

leafy spurge

loosestrife

musk or nodding thistle

perennial pepperweed

perennial sowthistle

poison hemlock

puncture vine

rush skeleton weed

Russian knapweed

Scotch thistle

silver-leaf nightshade

skeletonleaf bursafe

spotted knapweed

Syrian bean caper

tansy ragwort

white-top

wild carrot or Queen Anne’s lace

yellow starthistle

yellow toad flax

Rorippa austriaca

Swainsona salsula

Solarium rostratum

Alhagi camelorum

Circium arvense

Crupina vulgaris

Linaria da/matica

Centaurea diffusa

lsatis tinctoria

Convolvulus arvensis

Hyoscyamus niger

Aegilops cylindrica

Euphorbia esula

Lythrum salicaria

Carduus nutans

Lepidium latifolium

Sonchus arvensis

Conium maculatum

Tribulus terrestris

Chondrilla juncea

Centaurea repens

Onopordon acanthium

Solanum elaeagnifolium

Franseria discolor

Centaurea maculosa

Ygophyllum fabago

Senecio jacobaea

Cardaria draba

Daucus carota

Centaurea solstitialis

Linaria vulgaris

89
Nevada

Table F2. Designated noxious weed for the state of Nevada

Common Name Latin Name

Austrian fieldcress

Austrian peaweed

Camelthorn

Klamath weed

poison hemlock

water hemlock

Carolina horse nettle

white horse nettle

diffuse knapweed

Russian knopweed

leafy spurge

licorice

Mediterranean sage

Medusahead rye

puncture vine

perennial sorghum spp. including, but not limited to:

Johnson grass

Sorghum alum

perennial sweet sudan

Canada thistle

musk thistle

Scotch thistle

sow thistle

Iberian starthistle

purple starthistle

yellow starthistle

dalmation toadflax

whitetop or hoary cress

Rorippa austriaca

Sphaerphysa or Swainsona salsula

Alhagi camelorum

Hypericum perforatum

Conium maculatum

Cicuta spp.

Solanum carolinense

Solanum elaeagnifolium

Centaurea diffusa

Centaurea repens

Euphorbia esula

Glycyrrhiza lepidora

Salvia aethiopis

E/ymus or Taematherum caput-medusae

Tibulus tgerrestris

Sorghum halepense

Cirsium arvense

Carduus nutans

Onopordum acanthium

Sonchus arvenis

Centaurea iberica

Centaurea calcitrapa

Centaurea solstitialis

Lionaria dalmatica

Cardaria draba

Lepidium draba

L. repens

L . latifolium

Hymenophysa pubesens

Oregon

The Oregon State Department of Agriculture has developed a three category Noxious Weed rating system.

(1) An “A” designated weed is a weed of known economic importance which occurs in the state in small enough

infestations to make eradication/containment possible; or not known to occur, but its presence in neighboring

states make future occurrence seem imminent (Table F.l).

Recommended Action: Infestations are subject to intensive control when and where found.

(2) A “B” designated weed is a weed of economic importance which is regionally abundant, but of limited distribution in other counties (Table F.2).

Recommended Action: Moderate to intensive control at the state or county level.

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(3) A "T” designated weed is a noxious weed designated by the State Weed Board as a target weed species

(Table F.3).

Recommended Action: The department will focus intensive control measures (Appendix Table F.3).

Table F3. “A” designated weeds as determined by the Oregon Department of Agriculture.

Common Name Latin Name

Bearded creeper (Common crupina)

Camelthorn

Hydrilla

lberian star-thistle

Matgrass

Purple starthistle

Silverleaf nightshade

Smooth cordgrass

Squarrose knapweed

Whitestem distaff thistle

Wooly distaff thistle

Crupina vulgaris

Alhagi camelorum

Hydrilla verticillata

Centaurea iberica

Nardus stricta

Centaurea calcitrapa

Solanum eleagnifolium

Spartina alterniflora

Centaurea virgata

Carthamus leaucocaulos

Carthamus lanatus

Table F4. “B" designated weeds as determined by the Oregon Department of Agriculture.*

Common Name Latin Name

Austrian peaweed (Swainsonpea)

Buff alo burr

Bull thistle

Canada thistle

Dalmatian toadf lax

Diffuse knapweed

Dodder

Dyer’s Woad

Eurasian watermilfoil

Field bindweed

French broom

Giant horsetail

Gorse

Halogeton

Italian thistle

Japanese knotweed (Fleece flower)

Johnsongrass

Jointed goatgrass

Kochia

Leafy spurge

Meadow knapweed

Mediterranean sage

Medusahead rye

Milkthistle

Musk thistle

Perennial pepperweed

Sphaerophysa salsula

Solanum rostratum

Cirsium vulgare

Cirsium arvense

Linaria dalmatica

Centaurea diffusa

Cuscuta spp.

lsatis tinctoria

Myriophyllum spicatum

Convolvulus arvensis

Cytisus monspessulanus

Equisetum telmateia

Ulex europaeus

Halogeton glomeratus

Carduus pycnocephalus

Polygonum cuspidatum

Sorghum halepense

Aegilops cylindrica

Kochia scoparia

Euphorbia esula

Centaurea jacea x nigra

Salvia aethiopis

Taeniatherum caput-medusae

Silybum marianum

Carduus nutans

Lepidium latifolium

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Table F4. “B" designated weeds as determined by the Oregon Department of Agriculture.*

Common Name Latin Name

Poison hemlock

Puncturevine

Purple loosestrife

Quackgrass

Ragweed

Rush skeletonweed

Russian knapweed

Scotch broom

Scotch thistle

Slender-flowered thistle

South American waterweed (Elodea)

Spikeweed

Spiny cocklebur

Spotted knapweed

St. Johnswort (Klamath weed)

Tansy ragwort

Velvetleaf

Western horsetail

White top (Hoary Cress)

Wild proso millet

Yellow nutsedge

Yellow toadflax

*Species highlighted in bold type are likely to occur in eastern Oregon rangeland system.

Table F5. The ODA Target “T” List.*

Conium maculatum

Tribulus terrestris

Lythrum salicaria

Agropyron repens

Ambrosia arteimisiifolia

Chondrilla juncea

Acroptilon repens

Cytisus scoparius

Onopordum acanthium

Carduus tenuiflorus

Eloda dense

Hemizonia pungens

Xanthium spinosum

Centaurea maculosa

Hypericum perforatum

Senecio jacobaea

Abutilon theophrasti

Equisetum arvense

Cardaria spp.

Panicum miliaceum

Cyperus esculentus

Linaria vulgaris

Common Name Latin Name

Bearded creeper (Common crupina)

Gorse

Leafy spurge

Rush skeletonweed

Squarrose knapweed

Tansy ragwort

Wooly distaff thistle

Yellow stat-thistle

Crupina vulgaris

Ulex europaeus

Euphorbia esula

Chondrilla juncea

Centaurea virgata

Senecio jacobaea

Carthumus lanatus

Centaurea solstitialis

*Species highlighted in bold type are likely to occur in eastern Oregon rangeland system.

92
Utah

In Utah, county weed departments, private property owners, farmers, ranchers, and state and federal agencies are

encouraged to be aware of the presence of new and invading weeds on their property. The State Department of

Agriculture encourages all property owners to develop and implement control measures that will control and prevent

the spread of these invading weeds. It is the desire of the Department to prevent these invading weeds from

reaching a level of infestation that would require them to be declared a State Noxious Weed. Counties where

known infestations of these weeds occur are encouraged to declare these weeds as County Noxious Weeds, and to

develop and implement control programs against these weeds.

Table F6. Officially designated and published noxious weeds for the State of Utah, as per

the authority vested in the Commissioner of Agriculture under Section 4-17-3, Utah Noxious Weed Act:

Common Name Latin Name

Bermudagrass *

Bindweed (Wild Morning-glory)

Broad-leaved Peppergrass (Tall Whitetip)

Canada Thistle

Diffuse Knapweed

Dyers Woad

Perennial Sorghum spp., including but

not limited to:

Johnson grass, and

Sorghum Almum

Leafy Spurge

Medusahead

Musk Thistle

Quackgrass

Russian Knapweed

Scotch Thistle

Spotted Knapweed

quarrose Knapweed

Whitetop

Yellow Starthistle

Cynodon dactylon (L.) Pers.

Convolvulus spp.

Lepidium latifolium L .

Cirsium arvense (L.) Scop.

Centaurea diffusa Lam.

Isatis tinctoria L.

Sorghum halepense (L.) Pers.

Sorghum almum, parodi

Euphorbia esula L.

Taeniatherum caput-medusae (L.) Nevski

Carduus nutans L.

Agropyron repens (L.) Beauv.

Centaurea repens L.

Onopordium acanthium L.

Centaurea maculosa Lam.S

Centaurea squarrosa Roth

Cardaria spp.

Centaurea solstitialis L.

l Bermudagrass shall not be a noxious weed in Washington County and shall not be subject to provisions of the Utah Noxious Weed Law within the boundaries of

that county. It shall be a noxious weed throughout all other areas of the state of Utah and shall be subject to laws therein.

Table F7. Weeds designated and published in Utah as New and Invading Weeds:

Common Name Latin Name

Black Henbane

Dalmation toadflax

Goatsrue

Jointed goatgrass

Water hemlock

Poison hemlock

Yellow nutsedge

Wild proso millet

Silverleaf nightshade

Velvetleaf

Hyoscyamus niger

Linaria dalmatica

Galega officinalis

Aegilops cylindrica

Cicuta douglasii

Conium maculatum

Cyperus esculentus

Panicum miliaceum

Solanum elaeagnifolium

Abutilon theorphrasti

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Washington

Washington has three class system for classification of noxious weeds. Class A noxious weeds (Table F8) are

those noxious weeds not native to the state that are of limited distribution or are unrecorded in the state and whose

introduction to the state of Washington was not intentional, or whose intentional introduction poses a serious threat

to the state for which no containment is assured by the owner. Class B noxious weeds (Table F9) are those noxious

weeds not native to the state that are of limited distribution or are unrecorded in a region of the state and that pose a

serious threat to the region. “Class B designate” means those Class B noxious weeds whose populations in a

region or area are such that all seed production can be prevented within a calendar year. Class C are any other

noxious weeds (Table F10).

Table F8. Class A noxious weeds in Washington.

Common Name Latin Name

Syrian bean-caper

Texas blueweed

buffalobur

wild chervil

salt meadow cordgrass

common crupina

wild four o’clock

mouseear hawkweed

hedgeparsley

giant hogweed

johnsongrass

bighead knapweed

Vochin knapweed

Venice mallow

silverleaf nightshade

peganum

Mediterranean sage

dwarf snapdragon

purple starthistle

talian thistle

milk thistle

slenderflower thistle

unicorn-plant

velvetleaf

dyers woad

Zygophyllum fabago

Helianthus ciliaris

Solanum rostratum

Anthricus sylvestris

Spartina patens

Crupina vulgaris

Mirabilis myctaginea

Hieracium pilosella

Torilis arvensis

Heracleum mantegazzianum

Sorghum halepense

Centaurea macrocephala

Centaurea nigrescens

Hibiscus trionum

Solanum elaeagnifolium

Peganum harmala

Salvia aethiopsis

Chaenorrhinum minus

Centaurea calcitrapa

Carduus pycnocephalus

Silybum marianum

Carduus tenuiflorus

Proboscidea louisianica

Abutilon theophrasti

Isatis tinctoria

Table F9. Class B noxious weeds are designated as noxious weeds only in specific areas

of Washington state. Species listed here are Class B designates in some portion of eastern Washington, but may be confined to a small area. For specific location information,

refer to Chapter 16-750 WAS ‘State Noxious Weed List and Schedule of Monetary Penalties.”

Common Name Latin Name

blackgrass

blueweed

Scotch broom

white bryony

common bugloss

Alopecurus myosuroides

Echium vulgare

Cytisus scoparius

Bryonia alba

Anchusa officinalis

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Table F9. Class B noxious weeds are designated as noxious weeds only in specific areas

of Washington state. Species listed here are Class B designates in some portion of eastern Washington, but may be confined to a small area. For specific location information,

refer to Chapter 16-750 WAS “State Noxious Weed List and Schedule of Monetary Penalties.”

Common Name Latin Name

annual bugloss

camelthorn

common catsear

smooth cordgrass

common cordgrass

oxeye daisy

hybrid deadnettle

hedgehog dogtailgrass

Austrian fieldcress

gorse

orange hawkweed

yellow hawkweed

indigobush

black knapweed

brown knapweed

diffuse knapweed

meadow knapweed

Russian knapweed

spotted knapweed

lepyrodiclis

garden loosestrife

purple loosestrife

wand loosestrife

yellow nutsedge

hawkweed oxtongue

perennial peppetweed

tansy ragwort

longspine sandbur

rush skeletonweed

perennial sowthistle

leafy spurge

yellow star-thistle

Swainsonpea

musk thistle

plumeless thistle

Scotch thistle

Dalmatian toadflax

Eurasian watermilfoil

Anchusa arvensis

Alhagi pseudalhagi

Hypochaeris radicata

Spartina alterniflora

Spartina anglica

Chrysanthemum leucanthemum

Lamium hybridum

Cynosurus echinatus

Rorippa austriaca

Ulex europaeus

Hieracium aurantiacum

Hieracium pratense

Amorpha fruticosa

Centaurea nigra

Centaurea jacea

Centaurea diffusa

Centaurea jacea x nigra

Acroptilon repens

Centaurea maculosa

Lepyrodiclis holsteoides

Lysimachia vulgaris

Lythrum salicaria

Lythrum virgatum

Cyperus esculentus

Picris hieracioides

Lepidium latifolium

Senecio jacobaea

Cenchrus longispinus

Chondrilla juncea

Sonchus arvensis atvensis

Euphorbia esula

Centaurea solstitialis

Sphaerophysa salsula

Carduus nutans

Carduus acanthoides

Onopordum acanthium

Linaria genistifolia spp dalmatica

Myriophyllum spicatum

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Table F10. State of Washington Class C noxious weed list.

Common Name Latin Name

babysbreath

field bindweed

wild carrot

conical catchfly

spiny cocklebur

hoary cress

smothseed alfalfa dodder

garden rocket

black henbane

houndstongue

kochia

scentless mayweed

common mullein

bitter nightshade

poison-hemlock

puncturevine

cereal rye

spikeweed

common St. Johnswort

common tansy

yellow toadflax

bull thistle

Canada thistle

hairy whitetop

absinth wormwood

Gypsophila paniculata

Convolvulus arvensis

Daucus carota

Silene conoidea

Xanthium spinosum

Cardaria draba

Cuscuta approximata

Eruca vesicaria spp. sativa

Hyoscyamun niger

Cynoglossum officinale

Kochia scoparia

Ma tricaria maritima var. agrestis

Verbascum thapsus

Cloanum dulcamara

Conium maculatum

Tribulus terres tris

Secale cereale

Hemizonia pungens

Hypericum perforatum

Tanacetum vulgare

Linaria vulgaris

Cirsium vulgare

Cirsium arvense

Cardaria pubescens

Artemisia absenthium

96
Appendix G

Concerns of Land and Resource Managers

State Offices

Variation in priority of communities to be addressed by

the Vegetation Diversity Project reflects the relative

differences among the states in prominence of salt

desert shrub versus sagebrush steppe communities.

Idaho

In Idaho, most rehabilitation efforts occur in the Wyoming big sagebrush 8-14” precipitation zone. Frequent

fires and resulting cheatgrass monocultures are the

primary problem.

Research needs include identifying a variety of native

species for revegetation use. Compatible species

mixtures would be desirable to provide weed suppression through multiple niche occupancy. Squirreltail

was mentioned as a native grass capable of competing

with cheatgrass and medusahead and initiating

succession to a desired native plant community. Seed

sources for and variation among ecotypes of

squirreltail are a problem. Other native perennial

grasses mentioned were Thurber’s needlegrass which

is competitive but grazing sensitive and Sandberg

bluegrass. Bluebunch wheatgrass has been studied in

the Greenstripping Project and offers potential for

revegetation work. Additional species are needed.

Among characteristics to be considered in species for

revegetation, fire tolerance is critical and herbicide

tolerance would be desirable.

Follow-up management of rehabilitation efforts needs

to be researched. Proper grazing management in

particular needs to be researched and developed.

Special status plants identified for research efforts

include Happlopappus raddiatus (Snake River

goldenweed), Lepidium (a biennial on the Snake River

Plain), and Astragalus as a genus which includes many

species and may have wide application for a number of

special status plants. Knowledge of life histories and

propagation techniques are needed.

Collaboration with the Intermountain Greenstripping

Rehabilitation and Research Project in Idaho may

provide an opportunity to evaluate native species for

competitiveness and fire tolerance.

Nevada

Salt Desert Shrub, Wyoming big sagebrush and

Mountain big sagebrush are major community types in

Nevada. Of these, Wyoming big sagebrush was

considered the number one priority in terms of research needs for both reestablishment and maintenance of native plant communities primarily because of

fire frequency. Salt Desert Shrub communities don’t

burn frequently because of low fuel load characteristics. It was felt that Mountain big sagebrush communities generally have high enough precipitation so that

standard revegetation practices would suffice.

A primary management concern in Nevada is the

amount of large monotypic expanses of cheatgrass.

Of growing concern is the spread of medusahead into

areas previously dominated by cheatgrass.

Medusahead was thought to be confined to clay soil

sites. However, it has recently been noted as spreading onto loamy soil sites as it replaces cheatgrass

following frequent burning.

Squirreltail has been competitive with both cheatgrass

and medusahead. Squirreltail is a native, perennial

grass that appears to be capable of withstanding a

higher amount of grazing and of competition from

exotic plants than many native grasses in the sagebrush steppe. Managers have observed squirreltail

apparently establishing itself in medusahead dominated sites. Replacement of cheatgrass and

medusahead with squirreltail may be a means of

initiating successional reestablishment of perennial

native grasses in areas now dominated by exotic

annuals. Seed sources for squirreltail are needed.

Knowledge of ecotypic characteristics is also needed.

Juniper encroachment was also mentioned as a

concern for Nevada. Fire at early stages of development will often control juniper but, has a negative

impact on other wildlife browse species. A need for fire

tolerant plants and for native species in general was

mentioned from a management perspective.

Oregon and Washington

Appendix C in the May 1990 “Vegetation Diversity

Project: A Research and Demonstration Program Plan”

identifies the site priorities defined by the five eastern

Washington and Oregon Districts during meetings

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between Vegetation Diversity Project and District

personnel. Generally, “loamy” range sites receiving 7-

12 inches of annual precipitation with Wyoming big

sagebrush as the dominant shrub species were the

highest priority sites.

All Districts identified the need for sources of native

seed, information on ecotypic variability, any information on native forbs, seeding techniques and posttreatment management requirements.

Special status plant research needs included seedbank

inventory methods, basic life history information, and a

focus on genera such as Lupine, Eriogonum, Trifolium

and Astragalus as opposed to individual species.

Appropriate monitoring techniques was a consistently

high priority for special status plant programs.

Each of the Districts identified several other research

priorities, several of which are pertinent to the Vegetation Diversity Project.

Burns

Seeding techniques to enhance establishment and

plant materials screening/development (native species)

were identified as the primary priorities for the Vegetation Diversity Project.

Juniper expansion was identified as a major concern.

If, when and how to treat it are questions needing

answers.

Weeds identified as problems include cheatgrass,

medusahead which is expanding, and spotted and

diffuse knapweeds which are beginning to encroach.

An Environmental Assessment (EA) has been completed for a proposed burn and reseeding effort on a

2200 acre area on Coyote Rim near Silver Lake. The

area is dominated by Wyoming big sagebrush. Reseeding with bluebunch wheatgrass, squirreltail,

Thurber’s needlegrass, and needle-and-thread has

been suggested. Funding is lacking for the project.

Such a project might be useful as a demonstration.

Lakeview

Lakeview personnel considered maintenance of sites

with existing positive diversity as the highest priority.

Establishment of native plant materials on degraded

sites was second followed by plant materials identification/development.

Additional questions and concerns included: A quantifiable method of determining adequacy of vegetation

diversity is desired. What should it be, how is it

maintained where it exists, and when is treatment

needed to enhance diversity? An Ecological Site

Inventory (ESI) team is currently operating in the

District. District personnel questioned whether or not

ESI is appropriate, and, if so, how the information can

be used. Causes of juniper encroachment were

questioned. Should control be attempted? If so, how?

Sagegrouse decline is a concern. Questions were

raised about management implications such as a

relationship to grazing, fire, or conversion of lake beds

to waterholes.

More information about the potential use of fire as a

management tool is desired. Lakeview District has

used prescribed fire followed by direct bitterbrush

seeding.

An 85 acre enclosure with 5 acre replicated plots of

native seedings has been established. It is being

evaluated by District Range personnel and Squaw

Butte researchers.

Spokane

The communities most in need of research involve the

Channel scablands, Wyoming big sagebrush/

bluebunch wheatgrass sites. Desirable species of

interest include bluebunch wheatgrass, needle-andthread, Sandberg bluegrass, Idaho fescue, Wyoming

big sagebrush, bitterbrush, and arrowleaf balsamroot.

These sites are typically in the 9-12” precipitation zone

and have light sandy soils.

Cheatgrass is the number one weed problem with

diffuse knapweed in the shrub-steppe and spotted

knapweed in transition to forest areas becoming

noticeable.

A skeleton weed project is underway in the Juniper

Dunes Wilderness Area. Individual skeleton weed

plants have been located and mapped with a Trimble

Polycorder GPS system. Treatment with Tordon

(picloram) was scheduled for May. Follow-up monitoring will determine efficacy of the program.

A special status plant restoration plan will be implemented in Lincoln County for Polemonium pectinatum.

Prineville

Juniper encroachment, sagegrouse habitat needs, and

reclamation of dense sagebrush stands south of

Highway 20 were identified as major emphasis areas

for research. For juniper the questions were which

sites should be treated, how to treat, and what are

wildlife habitat tradeoffs with respect to treatment.

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Establishment of forbs for food and of grasses for

cover were the main sagegrouse needs identified. The

dense sagebrush stand south of Highway 20 is on

pumice soil with good moisture characteristics. Additional questions included what are the constraints to

restoration and how can they be overcome and what

weed control and seeding methods to use in WSAs.

Medusahead and knapweed were identified as noxious

weed problems. An increase in cheatgrass has also

been identified as a problem. An area along Murderers

Creek is being considered for a medusahead burn

treatment followed by seeding with squirreltail and/or

dropseed (Sporobolus, a warm-season grass).

Sporobolus has made an appearance along the John

Day River with a change in season of cattle use from

summer-long to winter-early spring use.

Spokane

The communities most in need of research involve the

Channel scablands, Wyoming big sagebrush/

bluebunch wheatgrass sties. Desirable species of

interest include bluebunch wheatgrass, needle-andthread, Sandberg bluegrass, Idaho fescue, Wyoming

big sagebrush, bitterbrush, and arrowleaf balsamroot.

These sites are typically in the 9-12” precipitation zone

and have light sandy soils.

Cheatgrass is the number one weed problem with

diffuse knapweed in the shrub-steppe and spotted

knapweed in transition to forest areas becoming

noticeable.

A skeleton weed project is underway in the Juniper

Dunes Wilderness Area. Individual skeleton weed

plants have been located and mapped with a Trimble

Polycorder GPS system. Treatment with Tordon

(picloram) was scheduled for May. Follow-up monitoring will determine efficacy of the program.

A special status plant restoration plan will be implemented in Lincoln County for Polemonium pectinatum.

Vale

An estimated 200,000 acres have potentially crossed a

threshold into an annual dominated plant community in

the Malheur and Jordan Resource Areas. These

communities are dominated by mainly cheatgrass and

medusahead with halogeton a problem on Salt Desert

Shrub areas and knapweeds becoming apparent. The

potential for restoration of these sites needs to be

determined.

Diversity of extensive crested wheatgrass seedings

resulting from the Vale Project could be enhanced by

additions of shrub and forb components.

Species needs identified by District staff include:

(Grasses) bluebunch wheatgrass, Thurber’s

needlegrass, Idaho fescue, Indian ricegrass, and basin

wildrye; (Shrubs) bitterbrush, curlleaf mountain mahogany and 4-winged saltbush; (Forbs) whatever can

be found. Seed sources for virtually all species are

lacking. Establishment techniques need to be identified or developed.

A threat or risk analysis to evaluate the need for action

against noxious weeds was identified as a need.

Utah

Utah felt that Salt Desert Shrub communities were its

greatest concern. The greatest research needs within

the Salt Desert Shrub community were oriented toward

establishment on low precipitation sites with alkaline

soils.

Shrubs for which additional information is desired

include shadscale, four-winged saltbush and winterfat.

Grasses noted were squirreltail, western wheatgrass

and warm season grasses such as Hilaria. For all of

these species, information is desired that would aid in

predicting ecological success and amplitude. More

information is needed in germination characteristics,

competition in establishment, and seeding technology.

An inventory is currently being developed for special

status plants. Specific research needs will be identified

later.

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* U.S. GOVERNMENT PRINTING OFFICE: 1994 - 589-123 / 01201 REGION NO. 10