U.S. Fish & Wildlife Service

Silene spaldingii

Janice Hill

Recovery Plan for 

Silene spaldingii

(Spalding’s Catchfly)

Silene spaldingii/Steve Wirt

Silene spaldingii/Steve Wirt
Recovery Plan for Silene spaldingii ● September 2007 

i 

Recovery Plan

for 

Silene spaldingii 

(Spalding’s Catchfly) 

Region 1 

U.S. Fish and Wildlife Service 

Portland, Oregon 
Recovery Plan for Silene spaldingii ● September 2007 

ii 

Disclaimer 

Recovery plans delineate reasonable actions that are believed to be 

required to recover and protect listed species. We, the U.S. Fish and Wildlife 

Service, publish recovery plans, sometimes with the assistance of recovery teams, 

contractors, State agencies, Tribal agencies, and other affected and interested 

parties. Objectives will be attained and any necessary funds made available 

subject to budgetary and other constraints affecting the parties involved, as well 

as the need to address other priorities. Recovery plans do not obligate other 

parties to undertake specific actions and may not represent the views nor the 

official positions or approval of any individuals or agencies involved in recovery 

plan formulation, other than our own. They represent our official position only

after they have been signed by the Regional Director or Director as approved. 

Recovery plans are reviewed by the public and submitted to peer review before 

we adopt them as approved final documents. Approved recovery plans are 

subject to modification as dictated by new findings, changes in species status, and 

the completion of recovery actions. Please check for updates or revisions at the 

website below before using. 

Notice regarding use of proprietary data: 

All plant locations given are approximate. Exact plant locations are 

proprietary data of the NatureServe/Heritage programs of Idaho, Montana, 

Oregon, Washington, and British Columbia, and cannot be redistributed by the 

U.S. Fish and Wildlife Service without specific authorization. Contact your local 

NatureServe/Heritage Program office to obtain a copy of their plant location 

database. 

Literature citation of this document should read as follows: 

U.S. Fish and Wildlife Service. 2007. Recovery Plan for Silene spaldingii 

(Spalding’s Catchfly). U.S. Fish and Wildlife Service, Portland, Oregon. xiii 

+ 187 pages. 

Electronic copies of this document will be made available at: 

<http://endangered.fws.gov/recovery/index.html> and 

<http://www.fws.gov/pacific/ecoservices/endangered/recovery/plans.html> 
Recovery Plan for Silene spaldingii ● September 2007 

iii 

Acknowledgements 

The wide-ranging nature of this rare species has necessitated the 

involvement of numerous individuals. We, the U.S. Fish and Wildlife Service, 

gratefully acknowledge the commitment and efforts of the following individuals 

to the recovery of Silene spaldingii. Without their assistance, this plan would not 

have been possible. 

LeAnn (Eno) Abell 

Idaho Bureau of Land Management

Julie Anderson and Mike Finch

Swanson Lakes Wildlife Area 

Joseph Arnett 

Washington Natural Heritage Program 

Barbara Benner 

Washington Bureau of Land 

Management 

Joanne Bigcrane

The Confederated Salish and Kootenai 

Tribes of the Flathead Reservation 

Florence Caplow 

Washington Natural Heritage Program 

Carrie Cordova 

Columbia Basin Fish and Wildlife 

Office 

Lynn Danly 

Idaho Bureau of Land Management 

Delores Davisson

Private Individual 

Frank Fink 

Idaho Natural Resources Conservation 

Service 

Zach Funkhouse and Company

Idaho Transportation Department 

Karen Gray

Idaho Conservation Data Center 

Jerome Hansen 

Idaho Department of Fish and Game 

Herman Harder 

Adams County Noxious Weed Control 

Board 

Tom Hawkins

Idaho Department of Lands/Craig 

Mountain 

Mike Hays 

Nez Perce National Forest 

Trish Heekin

Latah County Soil and Water 

Conservation District 

Janice Hill 

Idaho Conservation Data Center 
Recovery Plan for Silene spaldingii ● September 2007 

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Jasa Holt 

Washington Natural Heritage Program 

Jerry Hustafa 

Wallowa-Whitman National Forest 

Wayne and Jacie Jensen 

JenCrops 

Alan and Darla Klages

Private Landowners 

Peter Lesica 

Consultant 

Mark Lowry 

Idaho Bureau of Land Management 

Michael Mancuso 

Consultant 

Maria Mantas 

The Nature Conservancy of Montana 

Blair McClarin 

Nez Perce Tribe 

Bill Mervyn

Private Landowner 

Gary Miller

La Grande Fish and Wildlife Office 

Scott Mincemoyer 

Montana Natural Heritage Program 

Kendrick Moholt 

Private Landowner 

Roger Rosentreter

Idaho Bureau of Land Management 

Mike Rule

Turnbull National Wildlife Refuge 

Jerry Sawyer

Flathead State Park 

Joe Schmick

Private landowner 

Phil Shepard 

The Nature Conservancy of Oregon 

Angela Sondenaa 

Nez Perce Tribe 

Kimberly St. Hilaire

Bonneville Power Administration 

Diane Stutzman 

Washington Bureau of Land 

Management 

Roald Tangvald

Private Landowner 

Robert Taylor 

The Nature Conservancy of Oregon 

U.S. Fish and Wildlife Service 

Ecological Services Offices 

Boise, Idaho 

Helena and Kalispell, Montana 

La Grande, Oregon 

Spokane and Lacey, Washington 

Lynn Verlanic

Bison Range Complex National Wildlife 

Refuge 
Recovery Plan for Silene spaldingii ● September 2007 

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Jonathan Wald 

Fairchild Air Force Base 

John Williams

Oregon State University Extension 

Service 

Jim White and Company 

Idaho Department of Fish and Game 

Jean Wood 

Umatilla National Forest 

Eugene Yates

Wallowa-Whitman National Forest 

Ben Zamora

Washington State University Kramer 

Prairie Natural Area
Recovery Plan for Silene spaldingii ● September 2007 

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Executive Summary 

Current Species Status: Silene spaldingii (Spalding’s catchfly) is an 

herbaceous perennial plant in the pink family (Caryophyllaceae). It is a regional 

endemic found predominantly in bunchgrass grasslands and sagebrush-steppe, 

and occasionally in open pine communities, in eastern Washington, northeastern 

Oregon, west-central Idaho, western Montana, and barely extending into British 

Columbia, Canada. There are currently 99 known populations of S. spaldingii, 

with two thirds of these (66 populations) composed of fewer than 100 individuals 

each. There are an additional 23 populations with at least 100 or more individuals 

apiece, and the 10 largest populations are each made up of more than 500 plants. 

Occupied habitat includes five physiographic (physical geographic) regions: the 

Palouse Grasslands in west-central Idaho and southeastern Washington; the 

Channeled Scablands in eastern Washington; the Blue Mountain Basins in 

northeastern Oregon; the Canyon Grasslands of the Snake River and its tributaries 

in Idaho, Oregon, and Washington; and the Intermontane Valleys of northwestern 

Montana. Silene spaldingii was listed as a threatened species under the 

Endangered Species Act on October 10, 2001 (U.S. Fish and Wildlife Service 

2001). Silene spaldingii has been assigned a recovery priority number of 8C on a 

scale from 1C (highest) to 18 (lowest), indicating its taxonomic status as a full 

species, a moderate degree of threats or impacts, high potential for recovery, and 

potential conflict with economic activities. 

Habitat Requirements and Limiting Factors: In general Silene spaldingii

is found in open, mesic (moist) grassland communities or sagebrush-steppe 

communities. However, the species is occasionally found within open pine 

forests. The bunchgrass grasslands where S. spaldingii primarily occurs are 

characterized by either Festuca idahoensis (Idaho fescue) or F. idahoensis (Idaho 

fescue) with Agropyron spicatum = Pseudoroegneria spicata (bluebunch 

wheatgrass) except in Montana where the dominant bunchgrass is F. scabrella 

(rough fescue). The plant is found at elevations ranging from 365 to 1,615 meters 

(1,200 to 5,300 feet), usually in deep, productive loess soils (fine, windblown 

soils). Plants are generally found in swales or on northwest to northeast facing 

slopes where soil moisture is relatively higher. Silene spaldingii continues to be 

impacted by habitat loss due to human development, habitat degradation 

associated with adverse grazing and trampling by domestic livestock and wildlife, 

and invasions of aggressive nonnative plants. In addition, a loss of genetic fitness 
Recovery Plan for Silene spaldingii ● September 2007 

vii 

(the loss of genetic variability and effects of inbreeding) is a problem for many 

small, fragmented populations where genetic exchange is limited. Other impacts 

include changes in fire frequency and seasonality, off-road vehicle use, and 

herbicide spraying and drift. 

Recovery Strategy: The objective of the recovery program is to recover Silene 

spaldingii by protecting and maintaining reproducing, self-sustaining populations 

in each of the five distinct physiographic regions where it resides. Within each of 

these regions we have identified key conservation areas to focus conservation 

efforts at larger populations. A key conservation area possesses the following 

qualities: 

• Composed of intact habitat (not fragmented), preferably 40 acres (16 

hectares) in size or greater1

• Native plants comprise at least 80 percent of the canopy cover of the 

vegetation community 

• Adjacent habitat sufficient to support pollinating insects 

• Habitat is of the quality and quantity necessary to support at least 500 

reproducing individuals of S. spaldingii 

The protection and management of these key conservation areas, or areas that 

have the potential to serve as key conservation areas, forms the foundation of the 

recovery strategy for S. spaldingii. When possible, these key conservation areas 

should be surrounded by 300 acres of habitat that is intact or can be restored to 

eventually support S. spaldingii.

Recovery Goal, Objectives, and Delisting Criteria: The goal of the 

recovery program is to recover Silene spaldingii to the point where it can be 

delisted, i.e., to remove the species from threatened status. The primary 

objectives to meet this goal are to reduce or eliminate the threats to the species, 

and protect and maintain multiple reproducing, self-sustaining populations 

distributed across each of the five distinct physiographic regions where it resides 

sufficient to ensure the long-term persistence of the species. Delisting of the 

species will be considered when the following criteria have been met: 

1. Twenty-seven populations, with at least 500 reproducing Silene spaldingii 

individuals in each and with intact habitat, occur rangewide at key 

 

1

 In some regions, such as the already severely fragmented Palouse Grasslands, reaching a 

minimum size of 40 acres (16 hectares) of contiguous habitat may not be feasible 
Recovery Plan for Silene spaldingii ● September 2007 

viii 

conservation areas and are distributed throughout the 5 identified 

physiographic provinces as follows: 5 within the Blue Mountain Basins, 7 

within the Canyon Grasslands, 8 within the Channeled Scablands, 4 within 

the Intermontane Valleys, and 3 within the Palouse Grasslands. Given the 

uncertainty associated with creating new key conservation areas (i.e. 

transplanting) and the limited available habitat within the Palouse 

physiographic region, the delisting criteria of three key conservation areas 

within the Palouse Grasslands will be evaluated within 10 years (by the 

year 2017) based on new information. Populations with more than 500 

plants will be maintained at or above current population numbers. 

The number of populations/key conservation areas for each physiographic 

province was set at a minimum of three to preserve genetic diversity. For 

some regions, a greater number of key conservation areas are proposed to 

reflect the number of populations needed to maintain connectivity and, to 

the extent possible, preserve historical distribution across the remaining 

potential habitat estimated to be available. 

2. All 27 key conservation areas of Silene spaldingii are composed of at least 

80 percent native vegetation (by canopy cover), have adjacent habitat 

sufficient to support pollinating insects, and are not fragmented (i.e., 

intact; see criterion #1). 

3. Populations of Silene spaldingii at key conservation areas demonstrate 

stable or increasing population trends (less than a 10 percent chance that 

the population is declining) for at least 20 years. To address this criterion, 

consistent range-wide long-term monitoring methodologies that identify 

what parameters will be monitored, how, and at what frequency need to be 

developed. Acceptable statistical power and false-change error rates will 

be established at a later date when a standardized rangewide monitoring 

protocol is developed. 

4. Habitat management plans have been developed and implemented for all 

key conservation areas. These management plans will provide for the 

protection of Silene spaldingii habitat, and will also protect the ecosystem 

by addressing conservation of other rare species, reducing the identified 

threats (e.g., off-road vehicle use, adverse grazing and trampling by 
Recovery Plan for Silene spaldingii ● September 2007 

ix 

wildlife and domestic stock, herbicide application, etc.), protecting 

pollinators, enacting monitoring strategies, incorporating integrated pest 

management strategies, and incorporating appropriate fire management 

activities. 

5. Invasive nonnative plants with the potential to displace Silene spaldingii

have been continually controlled or eradicated within a 100-meter (328-

foot) radius of all S. spaldingii populations within key conservation areas. 

Certain invasive plants that are established and difficult to eradicate, as 

detailed for each physiographic province under Recovery Actions 1.1.4, 

1.2.4, 1.3.4, 1.4.4, and 1.5.5, may be controlled within 25 meters (82 feet) 

of S. spaldingii populations. 

6. Prescribed burning is conducted, whenever possible, to mimic historical 

fire regimes within a particular physiographic region in Silene spaldingii 

habitat. Prior to burning, presence/absence surveys for the plant will be 

completed. Prescribed burning of more than 30 percent of the individuals 

at a S. spaldingii population should not occur at any one time and should 

not take place when it may exacerbate invasive nonnative plant 

populations unless invasive nonnative plant control measures, monitoring, 

and a management strategy are in place prior to the prescribed burn. 

Where S. spaldingii is present, monitoring is enacted prior to and 

following the prescribed burn. Historical fire regimes are carefully 

analyzed utilizing the best available technology. 

7. Seed banking occurs ex situ first at all smaller Silene spaldingii

populations (not key conservation areas or potential key conservation 

areas) and second at all larger S. spaldingii populations (key conservation 

areas or potential key conservation areas) to preserve the breadth of 

genetic material across the species’ range. 

8. A post-delisting monitoring program for the species will be developed and 

ready for implementation. This program will be developed through 

coordination with the Bureau of Land Management, U.S. Forest Service, 

U.S. Fish and Wildlife Service, Tribes, States, The Nature Conservancy, 

and other interested parties. 
Recovery Plan for Silene spaldingii ● September 2007 

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Recovery Actions Needed: Silene spaldingii cannot be recovered if its 

habitat is not conserved and restored. The goal of this recovery plan is to manage 

self-sustaining S. spaldingii populations through good habitat (ecosystem) 

management at key conservation areas. This will be done through the following 

primary actions: 1) Conserve, identify, develop, and expand Silene spaldingii 

populations and habitat in each of the five physiographic regions where S. 

spaldingii resides; 2) Conduct general recovery actions across the range of Silene 

spaldingii; 3) Develop a post-delisting monitoring plan. 

These actions will be accomplished by developing and implementing 

habitat management plans at these key conservation areas that provide a strategy 

for managing Silene spaldingii and its habitat; these plans must address the threats 

to the species. Larger populations where small population sizes and 

fragmentation are less of a problem should be protected (kept from harm) before 

small, more fragmented populations that are more vulnerable to a loss of genetic 

diversity. To preserve genetic diversity, populations should be conserved in each 

of the five physiographic regions where the plant resides; if necessary, 

populations may need to be expanded or developed. Invasive nonnative plants 

need to be controlled within S. spaldingii habitat with minimal impact to the 

species itself by utilizing integrated pest management techniques. Fire 

management and prescribed burning must be conducted carefully and with sound 

monitoring strategies and scientific information. Development of lands where S. 

spaldingii resides, especially sites with large populations, should be prevented. 

Livestock grazing, where it occurs, will need to be conducted so that S. spaldingii

and its habitat are not deleteriously affected. To ensure these threats are 

adequately being addressed, monitoring and research are required to evaluate 

management actions. Additional needs include surveys to identify other S. 

spaldingii populations in need of protection or management, outreach to inform 

the public about the species so they may assist in conservation, and seed banks to 

protect the species from catastrophic losses. Funding is necessary to implement 

these actions. A regular review of this recovery plan is recommended so that new 

information may be incorporated and management adjusted accordingly. 

Total Estimated Cost of Recovery: The total estimated cost for recovery of 

Silene spaldingii is $8,666,000 with an average yearly cost across the first 5 years 

of $349,200 (Table 1). Of the estimated total, roughly a quarter of the dollars are 

for surveys and monitoring. 
Recovery Plan for Silene spaldingii ● September 2007 

xi 

Table 1. Expanded cost estimates through plan year 2040 (in $1,000 units). 

Actions refer to the primary recovery actions developed in this plan (see “actions 

needed” above). 

Recovery Action Year 

1* 2 3 Year Totals 

2007 17 322 339

2008 17 330 347 

2009 17 330 347 

2010 17 331 348 

2011 17 348 365 

2012 13 293 306 

2013 13 293 306 

2014 13 293 306 

2015 13 290 303 

2016 13 315 328 

2017 13 277 290 

2018 13 277 290 

2019 13 237 250 

2020 13 236 249 

2021 13 261 274 

2022 13 217 230 

2023 13 217 230 

2024 13 207 220 

2025 13 206 219 

2026 13 231 244 

2027 13 187 200 

2028 13 187 200 

2029 13 187 200 

2030 13 186 199 

2031 13 211 224 

2032 13 187 200 

2033 13 187 200 

2034 13 187 200 

2035 13 186 199 

2036 13 211 224 

2037 13 187 200 

2038 13 187 5 205 

2039 13 187 5 205 

2040 13 211 224 

TOTALS 462 8,194 10 8,666 

*Because Action 1 is a general action item, many of the costs associated with Action 1 are 

instead included under the more specific sub-actions of Action 2.
Recovery Plan for Silene spaldingii ● September 2007 

xii 

Date of Recovery: If recovery actions are prompt and effective, delisting 

might be possible in 2040. Because Silene spaldingii annual counts vary 

significantly in response to climatic events (i.e., precipitation, temperature) and 

individuals may exhibit prolonged dormancy (with no above ground parts) for up 

to 3 years, given what we currently know, a minimum of 20 years of monitoring 

will be needed to determine long term population trends. The estimated recovery 

date accounts for this long-term monitoring as well as the time it may take to 

supplement or establish new populations. 
Recovery Plan for Silene spaldingii ● September 2007 

xiii 

Table of Contents 

I. Introduction and Overview ..........................................................................................1

A. Introduction........................................................................................................1 

B. Species Description and Taxonomy...................................................................2 

C. Population Trends and Distribution ...................................................................6 

D. Life History and Ecology.................................................................................12 

E. Habitat Characteristics/Ecosystems..................................................................18 

F. Associated Species of Conservation Concern ..................................................25 

G. Reason for Listing/Threats Assessment...........................................................25 

1. Invasive Nonnative Plants (Factor A)...................................................26 

2. Problems Associated with Small, Geographically Isolated 

Populations (Factors A, E).............................................................31 

3. Changes in the Fire Regime and Fire Effects (Factor A)......................34 

4. Land Conversion Associated with Urban and Agricultural 

Development (Factor A) ................................................................38 

5. Adverse Livestock Grazing and Trampling (Factors A, C) ..................39 

6. Herbicide and Insecticide Spraying (Factor E) .....................................42 

7. Adverse Grazing (Herbivory) and Trampling by Wildlife 

Species (Factor C)..........................................................................43 

8. Off-Road Vehicle Use (Factors A, E)...................................................44 

9. Insect Damage and Disease (Factor C) .................................................45 

10. Impacts from Prolonged Drought and Climate Change (Factor 

E)....................................................................................................45 

11. Inadequacy of Existing Regulatory Mechanisms (Factor D)..............46 

H. Conservation Efforts ........................................................................................47 

1. Inventory Efforts ...................................................................................47 

2. Monitoring Efforts and Demographic Studies ......................................49 

3. Additional Sources of Scientific Information on Silene 

spaldingii........................................................................................51 

4. Invasive Nonnative Plant Control Efforts.............................................52 

5. Additional Conservation Actions..........................................................55 

I. Biological Constraints .......................................................................................56 

II. Recovery Strategy and Goals....................................................................................58

A. Recovery Strategy and rationale ......................................................................58 

B. Recovery Goals, Objectives, and Criteria ........................................................63 

Delisting Criteria........................................................................................64 

III. Recovery Program....................................................................................................67

A. Stepdown Outline of Recovery Actions...........................................................67 

B. Recovery Action Narrative...............................................................................73 

IV. Implementation Schedule ......................................................................................118

V. Literature Cited........................................................................................................134

In litt. References.................................................................................................159 

Personal Communications ...................................................................................165 
Recovery Plan for Silene spaldingii ● September 2007 

xiv 

Appendix A. Endangered and Threatened Species Recovery Priority Number 

Guidelines........................................................................................................... A-1

Appendix B. Scientific and common names used in the text.........................................B-1

Appendix C. Summary of Threats and Recommended Recovery Actions for 

Silene spaldingii.................................................................................................. C-1

Appendix D. Summary of Public, Agency, and Peer Review Comments on the 

Draft Recovery Plan for Silene spaldingii (Spalding’s Catchfly)....................... D-1

Appendix E. List of agencies and individuals we requested to provide comments 

for the Silene spaldingii Recovery Plan...............................................................E-1

List of Figures 

Figure 1. Silene spaldingii and a few of its closest look-alikes............................. 3 

Figure 2. Dichotomous key for Pacific Northwest Bunchgrass Silene.................. 5 

Figure 3. Rangewide distribution of Silene spaldingii........................................... 7 

Figure 4. Physiographic regions where Silene spaldingii has been found............. 8 

Figure 5. Known populations of Silene spaldingii............................................... 32 

Figure 6. The 14 known Silene spaldingii populations and 4 potential key 

conservation areas within the Blue Mountains Basins physiographic 

region. ....................................................................................................... 74 

Figure 7. The 22 known Silene spaldingii populations and 5 potential key 

conservation areas identified within the Canyon Grasslands physiographic 

region. ....................................................................................................... 75 

Figure 8. The 35 known Silene spaldingii populations and 7 potential key 

conservation areas identified within the Channeled Scablands 

physiographic region................................................................................. 76 

Figure 9. The 11 Silene spaldingii populations and 3 potential key conservation 

areas identified within the Intermontane Valleys physiographic region. . 77 

Figure 10. The 17 Silene spaldingii populations and 3 potential key conservation 

areas within the Palouse Grasslands physiographic region. ..................... 78 
Recovery Plan for Silene spaldingii ● September 2007 

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I. Introduction and Overview 

A. INTRODUCTION

Silene spaldingii (Spalding’s catchfly) is an herbaceous perennial plant. It 

is a regional endemic found predominantly in bunchgrass grasslands and 

sagebrush-steppe, and occasionally in open pine communities, in eastern 

Washington, northeastern Oregon, west-central Idaho, western Montana, and 

barely extending into British Columbia, Canada. S. spaldingii is affected by a 

variety of factors including competition with invasive nonnative plants; habitat 

destruction and fragmentation resulting from agricultural and urban development; 

habitat degradation; adverse grazing and trampling by domestic livestock and 

native herbivores; herbicide treatments; annual climatic conditions (i.e., drought 

cycles); climate change; alterations in fire frequency, intensity, and seasonality; 

off-highway vehicles; and a loss of genetic variation associated with small, 

fragmented populations. 

Silene spaldingii was listed as a threatened species under the Endangered 

Species Act on October 10, 2001 (U.S. Fish and Wildlife Service [USFWS] 

2001). The intent of this draft recovery plan is to guide implementation of the 

recovery of S. spaldingii. The ultimate goal of our recovery program is to 

eliminate or eradicate threats to persistence and restore populations of threatened 

or endangered species to the point at which the protections of the Endangered 

Species Act are no longer necessary, and the species may be delisted. The broad 

recovery recommendations in this plan are twofold: (1) resolve the impacts to the 

species; and (2) ensure self-sustaining populations in the wild. Definitions for 

some of the terms that will be commonly used within this document are provided 

in Box 1. 

Silene spaldingii has been assigned a recovery priority number of 8C on a 

scale of 1C (highest) to 18 (lowest), indicating a moderate degree of threats or 

impacts, high potential for recovery, potential conflict with economic activities, 

and its taxonomic status as a full species (Appendix A).
Recovery Plan for Silene spaldingii ● September 2007 

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B. SPECIES DESCRIPTION AND TAXONOMY

Silene spaldingii is a member of the pink or carnation family, the 

Caryophyllaceae. It was first collected by Henry Spalding around 1846 near the 

Clearwater River in Idaho (Oliphant 1934, pp. 98-99) and later described by 

Sereno Watson in 1875, based on the Spalding material (Watson 1875, p. 344). 

The species has no other scientific synonyms nor has its taxonomy been 

questioned. Common names include Spalding’s catchfly, Spalding’s silene, and 

Spalding’s campion. Silene spaldingii overlaps in range and is somewhat similar 

in appearance with several other species in the genus (see Figure 1): S. scouleri 

(Scouler’s catchfly), S. douglasii (Douglas’ catchfly) S. csereii (Balkan catchfly, 

not included in Figure 1), S. oregana (Oregon catchfly) and S. scaposa scaposa 

Box 1. Definition of terms as used in this recovery plan.

conservation – The controlled use and systematic protection of Silene spaldingii and its 

habitat. 

element occurrence record – Location information stored by each State or Province’s 

Natural Heritage Program or Conservation Data Center. 

extirpated – Eliminated from a certain area. 

fire regime – The frequency, intensity, and seasonality of fire within a given area. 

intact habitat – A place or environment for Silene spaldingii that is not fragmented by 

agricultural fields, urban developments, etc., and where the native ecosystem is 

functioning with few invasive nonnative plants and suitable habitat for pollinators. 

key conservation area – Significant populations and habitat of Silene spaldingii that 

have been identified by members of the technical team as the primary areas for 

recovery actions, protection, and conservation in this recovery plan. The defining 

criteria for key conservation areas are provided on page 42 of this plan. 

physiographic region – Geographic regions delineated by their physical characteristics. 

These regions are segregated in this recovery plan because of their significant 

differences in plant communities, climate, soil properties, fire regimes, and invasive 

nonnative plants. 

prolonged dormancy – When Silene spaldingii plants remain below the ground for up to 

3 years. Summer dormancy is an example. 

protection (protected areas) – Securing Silene spaldingii in areas that are either: (1) 

owned or managed by a government agency and with appropriate management 

standards in place for S. spaldingii; (2) managed by a conservation organization that 

identifies maintenance of the species as a primary objective for an area; or (3) on 

private lands with a voluntary, long-term conservation easement or covenant that 

commits present and future landowners to the perpetuation of the species. 

population – An aggregation of element occurrence records of Silene spaldingii that are 

within 1.6 kilometers (1 mile) of one another. 

rangewide distribution – Silene spaldingii’s distribution across all four states (Idaho, 

Montana, Oregon, and Washington) as well as British Columbia, Canada. 

site – Equivalent to a Silene spaldingii element occurrence record.
Recovery Plan for Silene spaldingii ● September 2007 

3 

 

Fi

gure 1. Silene spaldin

gii and a few of its closest loo

k-alikes. 
Recovery Plan for Silene spaldingii ● September 2007 

4 

var. scaposa (scapose silene) (Schassberger 1988, pp. 6,10; Youtie 1990, p. 2; 

Lichthardt 1997, pp. 2-3). A simple key for distinguishing Pacific Northwest 

bunchgrass Silene is provided in Figure 2. One member of the genus, S. latifolia 

ssp. alba (bladder campion), is an invasive nonnative plant that may be separated 

from S. spaldingii by its much larger, inflated flowers. Several other Silene 

included in Figure 2 below are nonnative but are not considered invasive at this 

time. 

Silene spaldingii is an herbaceous perennial, emerging in spring and dying 

back to below ground level in the fall. Plants range from 20 to 61 centimeters (8 

to 24 inches) in height, occasionally up to 76 centimeters (30 inches). There is 

generally one distinctively yellow-green stem per plant, but sometimes there may 

be multiple stems. Each stem bears 4 to 7 (up to 12 or more) pairs of leaves that 

are 5 to 8 centimeters (2 to 3 inches) in length, and has swollen nodes where the 

leaves are attached to the stem. All green portions of the plant (leaves, stems, 

calyx [defined below]) are covered in dense sticky hairs that frequently trap dust 

and insects, hence the common name “catchfly.” The plant has a persistent 

caudex (underground stem tissue) atop a long taproot (1 meter [3 feet] or longer in 

length). The long taproot makes transplanting the species difficult at best, and 

perhaps impossible. Typically S. spaldingii blooms from mid-July through 

August, but it can bloom into September. 

Three to 20 (sometimes over 100) flowers are horizontally positioned near 

the top of the plant in a branched arrangement (inflorescence). Flowers are 

approximately 1.5 centimeter (0.6 inch) long; however, the majority of the flower 

petal is enclosed within a leaf-like tube, the calyx, which resembles green material 

elsewhere on the plant and has 10 veins running from the flower mouth to the 

base of the flower. The visible portion of the five flower petals is small (2 

millimeters [0.08 inch]), cream-colored, and extends only slightly beyond the 

calyx. Attached to the visible flower petals (blades) are four to six very small (0.5 

millimeter [0.02 inch]) appendages, the same color as the blades (Figure 2). The 

flowers are perfect (have both male and female parts). Each fertilized flower 

matures vertically and becomes a many-seeded (up to 150 seeds) cup-like fruit 

capsule. Fruits mature from August until September and one stem may have both 

flowers and mature fruit capsules at the same time. Seeds are small (2 millimeters 

[0.08 inch]), wrinkled, flattened, winged, and light brown when mature. The 

above plant description is adapted from Schassberger (1988, pp. 5-6); Gamon 
Recovery Plan for Silene spaldingii ● September 2007 

5 

Figure 2. Dichotomous key for Pacific Northwest Bunchgrass Silene* 

 1a Styles generally 5 (the style is the narrowed portion of the pistil, connecting the stigma to the ovary) 

2a Flowers of two separate types (male and female), petal blade >5 millimeters 

.................................. bladder campion (Silene latifolia Poir. ssp. alba (P. Mill) Greuter and Burdet)^ 

2b Flowers of one type (contain both male and female parts), petal blade < 5mm 

....................................................................... Drummond campion (Silene drummondii Hook.) 

1b Styles generally 3 

3a Sepals (united) smooth/hairless, often bell-shaped, depressed and indented at the point where the flower 

attaches to its stem, lightly 15-20-nerved, becoming membrane-like in texture; petals white, blades (upper 

portion of petals) 4-6 mm, bilobed, appendages lacking or reduced to tiny bumps (appendages are projections 

located on the inner surface of a petal at the junction of the petal blade and petal claw) 

4a Sepals strongly inflated, up to 2 cm long when in post-flowering stage; fruit that forms is entirely 

surrounded by the sepal structure ...maidenstears (Silene vulgaris(Moench) Garcke – was S. cucubalus)^ 

4b Sepals slightly inflated, rarely as much as 1.5 cm long when in post-flowering stage; fruit that forms 

generally protrudes beyond the sepal structure.....................Balkan catchfly (Silene csereii Baumg.)^

3b Sepals (united) hairy, or plant not possessing the combination of characteristics listed under 3a 

5a Annual plant (germinates, flowers, produces seed, and dies during one growing season) 

6a Sepals (united) 25- to 30-nerved, shaped like an egg or inverted cone; depressed and indented at the 

point where the flower attaches to its stem; mostly over 20 mm long. Blade of petals with a small 

terminal notch in an otherwise rounded or blunt tip, 8-12 mm long. Appendages 2-5 mm 

long....................................................................................conoid cat (Silene conoidea L.)^

6b Sepals (united) 10-nerved, usually tubular, and mostly not depressed and indented at the point where the 

flower attaches to its stem, 4-15 mm long. Blade of petals shallowly to deeply 2-lobed, 2-9 mm long; 

appendages 0.2-0.4 mm long

7a Sepals very prominently nerved with stiff, coarse hairs. Blade of petals 5-9 mm long, 2-lobed at least 

half of the length; appendages about 0.2 mm long .................forked cat (Silene dichotoma Ehrh.)^ 

7b Sepals usually not prominently nerved with stiff, coarse hairs. Blade of petals 2-4 mm long, very 

shallowly-lobed at tip; appendages up to 0.4 mm long .............sleepy cat (Silene antirrhina L.)

5b Perennial plant (generally lives for multiple years; regenerating each growing season from a persistent 

underground stem (caudex) just beneath the soil surface which sits atop a long, narrow taproot) 

8a Petals, including the ovary stalk and blades, usually less than 10 (rarely 12) mm long; overall flower 

arrangement appears open and leafy ............................. Menzies’ catchfly (Silene menziesii Hook.) 

8b Petals, including the ovary stalk and blades, usually over 12 mm long; overall flower arrangement 

appears more compact than as described above and mostly with considerably reduced bracts (leaf-like 

structures) attached below. 

9a Blade of the petals 1-2 mm long, with no notch to a shallow terminal notch; ovary stalk smooth, 

without hairs or glands; appendages 4 (possibly 5-6); seeds inflated, about 2 mm long, the seed 

surface covered with alternating ridges and furrows....Spalding’s catchfly (Silene spaldingii S. 

Wats.) 

9b Blade of the petals usually over 2 mm long and deeply lobed; ovary stalk mostly hairy; appendages 

sometimes only 2; seeds usually not over 1.5 mm long, the seed surface not covered with alternating 

ridges and furrows.

10a Appendages 4 or 6, linear; petals equally 4-lobed or the middle lobes again deeply divided; 

auricles usually lacking (auricles are ear-shapd lobes on the outer margins of the upper part of the 

petal’s claw) ....................................................Oregon catchfly (Silene oregana S. 

Wats.) 

10b Appendages usually 2, or if 4 often not linear, or petals 2-lobed or unequally 4-lobed or with 

auricles

11a Ovary stalk 3-7mm long; petal blade 3-8 mm long, divided into 2 lobes for up to 1/3 of its 

length, rarely with a small lateral tooth on each margin of the petal blade

12a Plant with abundant glands on the overall flower arrangement itself and on the sepals; 

appendages mostly oblong and with more or less irregularly toothed margins, 1-3 mm 

long..................................................Scouler’s catchfly (Silene scouleri Hook.) 

12b Plant without glands or if present, only slightly glandular on the overall flower 

arrangement itself and on the sepals; appendages linear or narrowly oblong but not with 

irregularly toothed margins 1(rarely 3) mm long................Douglas’ catchfly (Silene

douglasii Hook.) 

11b Ovary stalk 1.5-2.5 mm long; petal blade 2.5-5.5 mm long, may be almost completely 

unlobed or may be heart-shaped..........................Scapose silene (Silene scaposa B. L. 

Robins. var. scaposa)

Petal Blade 

Appendage 

Style 

Sepal 

Schematic Silene 

*Key compiled by LeAnn Abell, U.S. 

Bureau of Land Management (L. Eno 

(Abell) in litt. 2004) from Hitchcock et 

al. 1964; Hitchcock and Cronquist 

1973; Harris and Harris 1994) 
Recovery Plan for Silene spaldingii ● September 2007 

6 

(1991, p. 22); Lesica and Heidel (1996, pp. 2-3); Lichthardt (1997, p. 2); and Hill 

and Gray (2004a, pp. 5-6). 

C. POPULATION TRENDS AND DISTRIBUTION

Within the United States, Silene spaldingii is known from four counties in 

Idaho (Idaho, Latah, Lewis, and Nez Perce), four counties in Montana (Flathead, 

Lake, Lincoln, and Sanders), one county in Oregon (Wallowa), and five counties 

in Washington (Adams, Asotin, Lincoln, Spokane, and Whitman) (Mincemoyer 

2005; Oregon Natural Heritage Program [ONHP] 2006; Idaho Conservation Data 

Center [ICDC] 2007; Montana Natural Heritage Program [MNHP] 2007; 

Washington Natural Heritage Program [WNHP] 2007; summarized in USFWS 

2007). Two element occurrence records of S. spaldingii are known in British 

Columbia, Canada, both are within 1.6 kilometers (1 mile) of plants in Montana 

(British Columbia Conservation Data Center [BCCDC] 2007), therefore we 

consider these plants to be within one single population. Figure 3 depicts the 

current rangewide distribution of S. spaldingii. 

The distribution and habitat of Silene spaldingii are primarily restricted to 

mesic slopes, flats or depressions in grassland, sagebrush-steppe, or open pine 

forest vegetation dominated by native perennial grasses such as Festuca 

idahoensis (Idaho fescue) or F. scabrella (rough fescue). Within its range, S. 

spaldingii occurs within five physiographic (physical geographic) regions: the 

Palouse Grasslands in west-central Idaho and southeastern Washington; the 

Channeled Scablands in eastern Washington; the Blue Mountain Basins in 

northeastern Oregon; the Canyon Grasslands of the Snake River and its tributaries 

in Idaho, Oregon, and Washington; and the Intermontane Valleys of northwestern 

Montana (see Figure 4). The Palouse Grasslands, a subset of the Pacific 

Northwest Bunchgrass Grasslands (Tisdale 1986a, p. 2), are somewhere in the 

middle of S. spaldingii’s range. 

Plants are tracked by State or province Natural Heritage Programs or 

Conservation Data Centers by sites or element occurrence records. When Silene 

spaldingii was initially listed in 2001, it was known from 98 separate element 
Recovery Plan for Silene spaldingii ● September 2007 

7 

Figure 3. Rangewide distribution of Silene spaldingii.
Recovery Plan for Silene spaldingii ● September 2007

8 

Figure 4. Physiographic regions where Silene spaldingii has been found
Recovery Plan for Silene spaldingii ● September 2007 

9 

occurrence records, or 58 populations if the element occurrence records within 1.6 

kilometers (1 mile) of one another are grouped together2

. Nine of these 58 

populations were located within the Blue Mountain Basins (excluding 1 extirpated 

population), 5 from the Canyon Grasslands, 21 from the Channeled Scablands 

(excluding 2 extirpated populations and 2 with poor location records), and 16 

within the Palouse Grasslands (excluding 1 extirpated population and 3 with poor 

location records), and 7 in the Intermontane Valleys (excluding 1 historical 

population and 1 with poor location records) (USFWS 2004, p. 3). When 

examined by state or province there were 7 populations in Idaho, 6.53

 in Montana, 

9 in Oregon, 35 in Washington, and 0.5 in British Columbia, Canada (USFWS 

2004, p. 1). Some 16,500 individual plants were estimated at the time of listing, 

although given the problems associated with counting plants due to prolonged 

dormancy this number should not be viewed as definitive (please see page 12 for 

a more detailed description of fluctuations in yearly population counts). 

Since Silene spaldingii was listed in 2001, increased survey efforts in 

suitable habitat have resulted in the identification of 39 new populations. Today 

we have 110 extant element occurrences in the United States and an additional 6 

sites that are not yet designated as element occurrences of S. spaldingii in 99 

populations (Figure 3): 14 in the Blue Mountain Basins, 22 in the Canyon 

Grasslands, 35 in the Channeled Scablands, 11 in the Intermontane Valleys, and 

17 in the Palouse Grasslands. When examined by state or province, there are 22 

populations in Idaho, 10.33 in Montana, 17 in Oregon, 49 in Washington, and 

0.66 in British Columbia, Canada (Mincemoyer 2005; ONHP 2006; BCCDC 

2007; ICDC 2007; MNHP 2007; WNHP 2007; summarized in USFWS 2007). 

The number of individual plants in each population ranges from one to several 

thousand. Several new sites within the Canyon Grasslands have expanded our 

knowledge of the range of the species by 50 miles from those locations known in 

2001. New occurrences are likely a result of increased survey effort, not an 

increase in actual plant distribution or vigor. The current estimated number of 

plants is approximately 28,750 individuals in the United States, although this 

 

2

 We defined populations of Silene spaldingii based on studies suggesting that genetic exchange 

via pollen transfer would typically not occur over a distance greater than 1.6 kilometers (1 mile). 

Recent improvements in mapping technology and criteria for designating extirpated populations 

have allowed us to refine the delineation of S. spaldingii populations, suggesting the 52 

populations originally identified in the Final Rule listing the species (U.S. Fish and Wildlife 

Service 2001) would have been more accurately reported as 58 populations. 

3

 One population, now with three sites, spans the border of the United States and Canada, reported 

here as 0.5 (in 2001) or now as 0.33 portion of a population. 
Recovery Plan for Silene spaldingii ● September 2007 

10 

number includes only above ground plants in any given year and therefore is an 

underestimation of the actual numbers of S. spaldingii (please see page 12 for a 

more detailed description of fluctuations in yearly population counts). 

It is expected that more populations of Silene spaldingii will be found in 

the future as survey efforts increase. To date, survey effort has been lower on 

privately owned lands than on publicly managed lands. Yet even with this lower 

survey effort, over half the known sites and estimated plant numbers occur on 

privately owned lands. Thirty-two of the known populations of S. spaldingii (32 

percent) occur on lands that are entirely in private ownership, with an additional 

18 populations (18 percent) in partial private ownership (Mincemoyer 2005; 

ONHP 2006; ICDC 2007; MNHP 2007; WNHP 2007; summarized in USFWS 

2007). The participation of private landowners, including organizations such as 

The Nature Conservancy, will therefore be vital in the recovery of this species. 

There are only 10 populations of Silene spaldingii that may be considered 

relatively large, each with over 500 individuals (Mincemoyer 2005; ONHP 2006; 

ICDC 2007; MNHP 2007; WNHP 2007; summarized in USFWS 2007). The 

largest population with over 10,000 plants is at The Nature Conservancy’s 

Dancing Prairie Preserve in Montana, followed by Garden Creek, Idaho, 

(managed by The Nature Conservancy and the Bureau of Land Management) with 

approximately 4,000 plants. The other 8 large populations range from 500 plants 

at Coal Creek, Washington, to some 2,385 individuals at Crow Creek on the 

Wallowa-Whitman National Forest in Oregon. Approximately 78 percent of the 

total known individuals of S. spaldingii are found within these few large 

populations. Of the 99 known S. spaldingii populations, two-thirds (66 

populations, or 67 percent) are small populations, each made up of fewer than 100 

individuals (Mincemoyer 2005; ONHP 2006; ICDC 2007; MNHP 2007; WNHP 

2007; summarized in USFWS 2007). Much of the remaining habitat occupied by 

S. spaldingii is fragmented by roads, agricultural fields, and other developments. 

When small populations with few individuals are isolated and genetic exchange is 

not possible, they become vulnerable to the loss of genetic variation and, 

ultimately, the loss of the population itself (Barrett and Kohn 1991, p. 4; Ellstrand 

and Elam 1993, pp. 219-225; see Section G-2 of this plan for further discussion). 

It is not known how many Silene spaldingii individuals and how much 

habitat may have been lost to human related activities during the last 150 years 
Recovery Plan for Silene spaldingii ● September 2007 

11 

since European settlement of this region. Historical documentation indicates the 

species was seldom collected (Hitchcock and Maguire 1947, p. 1), but because 

most land conversions within the plant’s historical range took place before 

botanical surveys had been done, we may never know how extensive or numerous 

S. spaldingii once was. Instead, we assume that the loss and alteration of large 

portions of suitable habitat have translated to a decline in population numbers. 

For example, the Palouse Prairie region (referred to in this plan as the Palouse 

Grasslands), centered around Pullman, Washington, and Moscow, Idaho, 

underwent a rapid and extensive conversion to agricultural lands around 1880 

prior to significant botanical surveys of the area. It is estimated that more than 99 

percent of the original Palouse Prairie and 47 percent of the Channeled Scablands 

habitat has been lost (Noss et al. 1995, p. 58), with obvious ramifications for S. 

spaldingii. Other areas such as the Canyon Grasslands have undergone a less 

dramatic land-use conversion, but have been and continue to be affected by 

adverse livestock grazing and trampling, and nonnative plant invasions. 

Four population extirpations or probable extirpations have been 

documented since tracking of Silene spaldingii began in the early 1980’s, with an 

additional three populations that are assigned element occurrence rankings of F in 

Natural Heritage Program datasets, indicating subsequent surveys by qualified 

botanists have failed to find S. spaldingii individuals (Schassberger 1988, p. 26; 

Gamon 1991, pp. 11-13; ONHP 2006; ICDC 2007; MNHP 2007; WNHP 2007; J. 

Holt, WNHP, in litt. 2007; summarized in USFWS 2007). At least three other 

sites that formerly supported the species have been documented as having no 

plants present at the last visit (J. Holt, in litt. 2007). Populations are not 

necessarily considered extirpated, however, if sites are revisited and S. spaldingii

is not found, because plants at these sites may be exhibiting prolonged dormancy 

(see discussion in Section D, Life History and Ecology, below). Subsequent visits 

are needed to confirm extirpations at these sites. 

Because of its prolonged dormancy, monitoring Silene spaldingii to track 

trends requires long term data sets. The only area where monitoring has occurred 

for a long enough time period to begin detecting trends is at the Dancing Prairie in 

Montana where the plant has been monitored in 1991, 1992, 1993, 1994, 1995, 

1996, 2003, 2004, 2005, and 2006 (Lesica 2005, p. 2; Lesica and Crone 2007, 

Table 1). The mean density of S. spaldingii over this time period shows a 

statistically significant downward trend. The authors suggest this may be a true 
Recovery Plan for Silene spaldingii ● September 2007 

12 

downward trend, the trend may be linked to a drought in the latter half of the 10 

year period, or the trend may actually be an increase in prolonged dormancy since 

1991-1996 (Lesica 2005, pp. 2-3). 

D. LIFE HISTORY AND ECOLOGY

At the end of the first 5 years of a demography study, 72 percent of Silene 

spaldingii plants remained alive (Lesica 1997, p. 355), suggesting that individuals 

may regularly reach an age of at least 15 to 20 years. However, it is hypothesized 

some individuals may live up to 30 years of age or longer. Seedlings generally 

sprout in spring, form rosettes the first year, and occasionally flower the second 

year (Lesica 1995, p. 6), but generally flowering does not occur until during or 

after the third season (Lesica 1997, p. 348). Adult plants emerge in spring, 

usually May, as either a stemmed plant, a rosette, or occasionally as a plant with 

both rosette(s) and stem(s) (Hill and Weddell 2003, p. 1). Stemmed plants may 

remain vegetative or may become reproductive in July or August. Plants senesce 

or wither in fall (September or October), reappearing the next spring (Hill and 

Gray 2004a, p. 44). 

A demographic study in Montana found Silene spaldingii exhibits 

prolonged or summer dormancy (Lesica and Steele 1994, p. 210; Lesica 1997, p. 

349); that is, plants can remain below the ground, without leaves, for up to 6 years 

when conditions are unfavorable (Lesica and Crone in review, p. 10). In one 

study plants were found to exhibit prolonged dormancy for 1 year 76 percent of 

the time and for 2 years 16 percent of the time (Lesica and Crone in review, p. 

10). Another demographic study in Idaho across 5 years (2002 to 2006) found 

only 21 of 150 plants had dormant periods, 20 plants were dormant for 1 year, and 

1 plant was dormant for 2 years (J. Hill, ICDC, in litt. 2007a, p. 2). 

The Montana study concluded that prolonged dormancy increases Silene 

spaldingii’s fitness and may be a way to obtain below-ground resources that limit 

the production of flowers or fruits (Lesica and Crone in review, p. 11). This 

increased fitness in dormant plants was assumed since dormant plants had similar 

survival and growth, and were more likely to flower the following year compared 

to vegetative plants, resulting in a greater reproductive value associated with the 

dormant state (Lesica and Crone in review, pp. 1, 10, 11). Discriminant function 

analysis showed that prolonged dormancy was dependent on both external 
Recovery Plan for Silene spaldingii ● September 2007 

13 

(precipitation) and internal (life history stage) factors; that is, prolonged 

dormancy was associated with the plant having flowered the previous year and 

following high summer (July through September) precipitation and lower fall 

(October) precipitation the previous year (Lesica and Crone in review, pp. 1, 2, 

10, and 11). In contrast, two demographic studies in the Canyon Grasslands of 

Idaho found equal numbers of vegetative and reproductive plants become dormant 

the following year; and after dormancy two to three times more individuals 

emerge as vegetative plants than as reproductive plants (results from Lichthardt 

and Gray 2003; Gray and Lichthardt 2004; Hill and Gray 2005a; and summarized 

in Gray and Hill 2006, Appendix 1). 

A demographic study in the Canyon Grasslands of Idaho conducted for 5 

years on Silene spaldingii (2002 to 2006) (Hill and Weddell 2003; Hill and Gray 

2004b; Hill and Gray 2005b; Hill 2006; J. Hill, in litt. 2007a) included two 

monitoring periods during each growing season, once early in the season soon 

after emergence (early June) and once late in the season at flowering time (early 

August). Most monitoring that has occurred for S. spaldingii has taken place only 

once, later in the season when individuals are flowering. Annual censuses at early 

sampling showed large proportions of the plants above ground were rosette plants 

(averaging 34 percent), the remainder were stemmed individuals. Annual 

censuses at the later sampling revealed large proportions of both stemmed and 

rosette plants had disappeared (39 percent). The majority of the plants that had 

disappeared (77 percent) were rosette plants. The authors performed 

demographic analyses on both early and late data sets to determine how 

demographic parameters would have differed. Monitoring only at flowering time 

would have resulted in an under-representation of the rosette plant stage class, 

under-representation of the total plants present, over-representation of dormancy 

and the duration of dormancy, and erroneous recruitment determinations (J. Hill, 

in litt. 2007a, p. 2). Another demographic study in the Canyon Grasslands of 

Idaho is showing similar results (Lichthardt and Gray 2003; Gray and Lichthardt 

2004; Hill and Gray 2005a; Gray and Hill 2006). The demographic study in 

Montana found only a 10 percent difference between early and late monitoring 

(Lesica 2005, p. 1). 

Prolonged dormancy of Silene spaldingii can make population estimates 

and monitoring difficult. In one demography study in Montana, dormancy varied 

from a yearly low of 11 percent of individuals dormant to a high of 74 percent 
Recovery Plan for Silene spaldingii ● September 2007 

14 

(Lesica 1997, p. 351). Long-term monitoring is necessary to accurately assess 

population trends of S. spaldingii. Due to this ability to go dormant, population 

estimates of S. spaldingii, if based on visible plants, will always be lower than the 

actual population size (P. Lesica, private consultant, in litt. 2003, pp.1-2). 

Seed dispersal studies have not yet been conducted on Silene spaldingii. 

However, the capsules of S. spaldingii serve as an open cup from which seeds are 

likely carried by the wind, jostled out by passing wildlife, or tossed when plants 

are knocked over. Seeds are small, flat, and somewhat winged. Plant height and 

seed characteristics suggest that short-distance wind dispersal may be common. 

In addition, the sticky nature of the plant makes it possible for portions of the 

plant to break off and stick to the fur of passing animals. This method of seed 

dispersal is probably infrequent but may provide an opportunity for more long 

distance dispersal. No studies have investigated how long S. spaldingii seeds may 

remain dormant in the soil before they lose their viability or if they survive 

passage through the digestive tract of herbivores. A recent study on the closely 

related S. douglasii found high initial seed germination but that seed viability 

declines to about 20 percent after 7 to 8 years (Lofflin and Kephart 2005, p. 

1695). 

Two laboratory studies have looked at seed germination for Silene 

spaldingii (Lesica 1988a, 1993; A. Raven, Berry Botanic Garden, pers. comm.

2004). Both studies found an increase in germination after cold stratification (a 

period of chilling), suggesting germination occurs predominantly in the spring. 

However, results from a 4-week cold stratification period (Lesica 1988a, pp. 1-2, 

1993, p. 198; 1997, p. 348) indicate some germination could occur in fall when 

shorter chilling periods would occur. Lesica’s (1988a, p. 1) study found 5 percent 

germination after 35 days without cold stratification and 60 to 70 percent 

germination after a 30-day cold stratification. An 8-week versus a 4-week cold 

stratification period greatly enhanced germination (Lesica 1993, pp. 197-198). 

Preliminary results from the Berry Botanic Garden in Portland, Oregon, found the 

highest germination (86 percent) with an 8-week cold stratification treatment 

followed by growth in a germination chamber with alternating periods of time at 

temperatures of 10 and 20 degrees Celsius (50 and 68 Fahrenheit; thought to 

mimic night and day time temperature fluctuations) (A. Raven, pers. comm. 2004, 

p. 1). 
Recovery Plan for Silene spaldingii ● September 2007 

15 

In a demography study in Montana, Lesica (1997, p. 355) found that 

significant recruitment (germination and seedling survival) of Silene spaldingii 

occurred in only 2 of 7 years, indicating recruitment is a rare and sporadic event. 

A continuation of this study found significant recruitment in 3 of 13 years (Lesica 

and Crone in review, Figure 1). After germination, Lesica (1988a, p. 1) in 

Montana found seedlings began to grow immediately in small pots, continued 

growing for 2 months, remained green for another month, turned brown and went 

dormant for a month and a half, and then developed new leaves. It is 

hypothesized the initial growth would reflect early spring growth within native 

habitats, the dormant period would occur during the hot, dry summer, and regrowth would reflect fall growth (Lesica 1988a, p. 1). Another greenhouse study 

did not find the same dormant period: after germination seedlings grew for over a 

year and began bolting 13 months later (Hill et al. 2001, p. 8; Hill and Gray 

2004a, p. 48). 

Measuring new recruits (seedlings) of Silene spaldingii within native 

habitats can be problematic. Adult plants can produce rosettes that are similar to 

those of seedlings. Various characteristics have been used to distinguish adult 

rosettes from seedling rosettes, including: seedling rosettes with a conspicuous 

lack of stem material between leaves (Lesica 1997, p. 349; Hill and Weddell 

2003, pp. 7-8; Hill and Gray 2004b, p. 48; Lesica 2005, p. 1) although this 

characteristic does not appear reliable (Hill and Weddell 2003, pp. 7-8), seedling 

rosettes with hairless leaves (Hill and Gray 2000, p. 6; Hill and Weddell 2003, p. 

8), seedling leaves with hairs only along the edges (Hill and Gray 2004b, p. 48), 

nearly hairless seedling rosettes (P. Lesica, in litt. 2006, p. 2), seedling rosette 

leaves not being opposite or equal sized as they are in adult rosettes (P. Lesica, in 

litt 2006, p. 2), and leaf size (Hill and Weddell 2003, p. 8). None of these 

techniques are definitive and persons performing monitoring for the species 

should be aware of this constraint. A demographic study in Idaho has concluded 

no diagnostic anatomical features could be identified to distinguish seedling 

rosette plants from older rosette plants and therefore made the distinction based 

on long-term monitoring. A rosette plant that appeared at a location where no 

plant had occurred in the previous 3 years was considered a seedling (J. Hill, in 

litt. 2007a, p. 1). 

Silene spaldingii reproduces only by seed, with no means of vegetative 

reproduction (spread by vegetative growth) (Lesica 1993, p. 194). The species is 
Recovery Plan for Silene spaldingii ● September 2007 

16 

partially self-compatible, meaning the pollen is capable of fertilizing the female 

reproductive structures on the same plant. Flowers of S. spaldingii contain both 

male (stamen) and female (pistil) parts. However, the male parts mature, shed 

pollen, and wither prior to the female parts of the same flower becoming receptive 

(Lesica 1988b, p. 2). This reduces the chances of self-pollination within an 

individual flower, but still allows for pollination between different flowers on the 

same plant. 

Using mesh bags to exclude pollinators, Lesica (1993, pp. 195-200) found 

significant decreases in fruit development, the number of seeds produced per fruit, 

germination after both a 4- and 8-week cold stratification period, seedling 

survival, and juvenile growth. Low pollinator visitation rates and a pollinator 

shifting more readily from Silene spaldingii to another plant species (lower 

pollinator constancy) were both correlated with reduced fruit set in S. spaldingii 

(Lesica and Heidel 1996, p. 9). Lesica and Heidel (1996, p. 9) found pollinator 

constancy and visitation rates were lower at sites where large displays of flowers 

competed for the primary pollinator, the bumblebee Bombus fervidus. 

Observational data at Garden Creek found B. fervidus switching from S. 

spaldingii to Hypericum perforatum (St. Johnswort), suggesting that H . 

perforatum will compete with S. spaldingii for pollinator services (Lesica and 

Heidel 1996, p. 8 and 11). Collectively these studies suggest that S. spaldingii

reproduces best when outcrossing occurs, pollinators are essential in maintaining 

the fitness of S. spaldingii, adjacent invasive nonnative plants may negatively 

affect reproduction, and pollinators must consistently visit S. spaldingii. 

Pollinators were observed for over 30 hours, both during the day as well as 

the night, at each of five Silene spaldingii populations across the range of the 

species, one in Idaho, one in Montana, one in Oregon, and two in Washington 

(Lesica and Heidel 1996, p. 5). The populations selected occurred in relatively 

intact habitat with at least 100 plants in a population. Across populations, the 

bumblebee Bombus fervidus accounted for over 83 percent of all visitations 

(Lesica and Heidel 1996, p. 7). Other pollinators included solitary bees from the 

Halictidae family (Lasioglossum ovaliceps, Halictus tripartitus, Dienoplus 

rugulosis, Lasioglossum spp.), one wasp visit, and a minor contribution from a 

night-pollinating moth species in Oregon (Lesica and Heidel 1996, p. 7). 
Recovery Plan for Silene spaldingii ● September 2007 

17 

Bombus fervidus is known from southern Canada and most of the United 

States, except the extreme south (Thorp et al. 1983, p. 27). The species is 

common within grasslands but rare in wooded foothills, and tends to build its 

nests either on or just below the surface of the ground, generally within the first 

0.3 meters (1 foot) of soil (Hobbs 1966, p. 34). The queen emerges from 

hibernation in spring and establishes a seasonal colony that can contain over 200 

individuals by fall (Hobbs 1966, p. 37). In California, the queen flies from early 

April to late October, workers from early May to late October, and males from 

early July to early October (Thorp et al. 1983, p. 27). Bombus species are 

generally less faithful to a particular plant species than honey bees (Apis spp.) 

within a foraging trip and do not specialize on pollination of any one species or 

group of plant species; in other words, they utilize a wide range of plant species 

for nourishment (Stephen et al. 1969, p. 118). 

The distance that pollinators can travel is significant to plants because 

pollen transfer and seed dispersal are the only mechanisms for genetic exchange. 

In general pollinators will focus on small areas where floral resources are 

abundant; however, occasional longer distance pollination will occur, albeit 

infrequently. No research has been conducted on flight distances of Bombus 

fervidus, but one study documented that bees fly 1 kilometer (0.6 mile) or less 

(Steffan-Dewenter and Tscharntke 1999, pp. 434-435). In another study, the 

bumblebee Bombus terrestris did not fly more than a distance of 621 meters 

(2,037 feet; Osborne et al. 1999, pp. 524-526). Another bumblebee-pollinated 

plant species, Scabiosa columbaria (dove pincushions), experienced decreased 

pollen flow at a patch isolation distance of 25 meters (82 feet), and little to no 

pollen transfer when patches were isolated by 200 meters (656 feet) (Velterop 

2000, p. 65). 

In contrast, another study found that displaced Bombus terrestris species 

were able to return to their nests from distances over 9 kilometers (5.6 miles) 

(Goulson and Stout 2001, p. 108). One study found that B. terrestris workers 

were recaptured while foraging on super-abundant resources at distances of 1.75 

kilometers (1.1 miles) from the nest (Walther-Hellwig and Frankl 2000, p. 303). 

One study that looked at genetics of fragmented populations of the rare plant 

Scutellaria montana (large-flowered skullcap) hypothesized a maximum distance 

over which pollen dispersal rates were high enough to counteract genetic drift at 8 

kilometers (5 miles), and higher levels of selfing due to an absence of pollinators 
Recovery Plan for Silene spaldingii ● September 2007 

18 

at only 2 kilometers (1.2 miles) (Cruzan 2001, p. 1578). These studies suggest 

variability in the distances over which pollen transfer may occur. Silene 

spaldingii populations are generally small and therefore do not represent “superabundant” resources. We expect that most pollen exchange will be rare for 

distances over 1.6 kilometers (1 mile). This is one of the rationales we used when 

grouping Silene spaldingii sites within 1.6 kilometers (1 mile) of one another as 

populations. Recently the Washington Natural Heritage Program increased its 

separation distances of element occurrence records from 1 to 2 kilometers (0.6 to 

1.2 miles) based on further research into pollinator flying distances (J. Holt, in litt. 

2006). 

Baldwin and Brunsfeld (1995) did a preliminary genetic analysis of Silene 

spaldingii. Leaf samples were taken from five sites, one in Idaho, one in 

Montana, one in Oregon, and two in Washington. Samples were collected during 

a year with low precipitation when many plants remained dormant and 

consequently sample sizes were small. All sites where material was collected 

were known to have at least 200 individuals in good years. This study (Baldwin 

and Brunsfeld 1995, p. 4) found that genetic diversity of S. spaldingii was 

comparable to that of other rare Silene (S. regia [Dolan 1994, pp. 968-970] and S. 

hawaiiensis [Westerbergh and Saura 1994, pp. 1489-1492]). The only exception 

was that the Dancing Prairie site in Montana had lowered genetic diversity. This 

finding is consistent with the results of Lesica and Heidel (1996, p. 7), who 

reported lower pollinator visitation rates and a higher incidence of fruit abortion at 

the Dancing Prairie site. Baldwin and Brunsfeld (1995, pp. 2-3) also suggested 

that genetic diversity varies across the species’ range, indicating that sites 

throughout the range of S. spaldingii need to be protected in order to preserve the 

full array of genetic variability within the species. 

E. HABITAT CHARACTERISTICS/ECOSYSTEMS

Silene spaldingii occurs at elevations between 365 to 1,615 meters (1,200 

to 5,300 feet) (ONHP 2006; ICDC 2007; MNHP 2007; WNHP 2007; summarized 

in USFWS 2007). In general summers are hot and dry, while winters are cool to 

cold and moist across the range of S. spaldingii (Western Regional Climate 

Center 2003a, pp. 2, 6, 10, 17); anywhere from 45 to 65 percent of the 

precipitation occurs during the winter months (Daubenmire 1942, p. 59). A 

drought period occurs in mid and late summer when precipitation is minimal and 
Recovery Plan for Silene spaldingii ● September 2007 

19 

temperatures are high (Tisdale 1983, p. 230). Consequently, most of the 

vegetation does not grow in summer, but can remain active during the winter 

months when moisture is more readily available. The majority of growth, 

however, occurs in spring (Daubenmire 1970, p. 6). Silene spaldingii is different; 

it grows during the summer drought when the majority of the surrounding 

vegetation is dormant. 

Annual precipitation ranges from 254 millimeters (10 inches) near Odessa, 

Washington, to 610 millimeters (24 inches) near Moscow, Idaho (Western 

Regional Climate Center 2003b, pp. 1-2, 13-14). Mean annual temperature 

ranges from a low of 6 degrees Celsius (43 degrees Fahrenheit) at Enterprise, 

Oregon, to 13 degrees Celsius (55 degrees Fahrenheit) at Wawawai, Washington 

(Hill and Gray 2004a, p. 34). Average temperatures can vary significantly from 

winter to summer and from day to night. These are general climatic parameters; 

variations across the range of S. spaldingii can be dramatic and are heavily 

influenced by elevation, geography, and topography (Hill and Gray 2004a, p. 34-

35). 

Silene spaldingii is generally found in deep loamy soils (fertile soils 

composed of organic material, clay, sand, and silt) and in more mesic, moist sites 

such as northern slopes, swales, or other small landscape features (Hill and Gray 

2004a, pp. 23-24). These mesic sites are highly productive, with total plant cover 

and forage dry weight sometimes three times greater than drier, more shallowly 

soiled bluebunch wheatgrass (Pseudoroegneria spicata) communities (Johnson 

and Simon 1987, p. 9). Soils in the tri-state (Idaho, Oregon, and Washington) 

area are loess (wind-dispersed) and ash (from volcanic eruptions) influenced 

(Tisdale 1986b, pp. 1-2; Johnson and Simon 1987, pp. 8-9), while soils in 

Montana are more glacially influenced (Schassberger 1988, p. 48). S. spaldingii

is found on a wide range of slopes, from flat areas to slopes as great as 70 percent. 

Most occurrences are found on grades ranging from 20 to 40 percent slope (Hill 

and Gray 2004a, p. 24), although this may be an artifact of where intact habitat 

has not been converted to other uses. 

Silene spaldingii is found primarily within the more mesic grasslands of 

the Pacific Northwest Bunchgrass association/type, extending from Washington 

and Oregon into parts of Montana and into adjacent British Columbia, and 

Alberta, Canada (Tisdale 1983, p. 223). This area has mistakenly, at times, been 
Recovery Plan for Silene spaldingii ● September 2007 

20 

broadly described as the “Palouse Prairie” or the Palouse region (Tisdale 1983, p. 

223; Lichthardt and Moseley 1997, p. 1; U.S. Fish and Wildlife Service 2001, p. 

51598). The term “Palouse Grasslands” will be used in this recovery plan to 

delineate a much narrower area than that covered by the Pacific Northwest 

Bunchgrass Grasslands (Figure 4). Pacific Northwest bunchgrasses where S. 

spaldingii is found are characterized by either Festuca idahoensis (Idaho fescue) 

or by both F. idahoensis and Pseudoroegneria spicata (bluebunch wheatgrass) 

and Festuca idahoensis (Idaho fescue) in Idaho, Oregon, and Washington; and 

with Festuca idahoensis sometimes co- or subdominant with Festuca scabrella

(rough fescue) in Montana (Tisdale 1983, p. 225). The summer drought across S. 

spaldingii’s range prevents tree species from establishing in most S. spaldingii

habitats and results in a climax grassland community (Daubenmire 1968, pp. 432, 

437-438). Exceptions include the Dancing Prairie in Montana and Turnbull 

National Wildlife Refuge in Washington. At the Dancing Prairie site it is thought 

that tree establishment is probably prevented by a combination of summer 

drought, competition with grasses, and wildfire (P. Lesica, in litt. 2007a, p. 1). 

Primary grassland habitat types within the Pacific Northwest bunchgrass 

grasslands include: 1) Festuca idahoensis – Symphoricarpos albus (snowberry); 

2) Festuca idahoensis – Rosa spp. (rose); 3) Festuca idahoensis – Koeleria 

cristata (prairie junegrass); 4) Pseudoroegneria spicata – Festuca idahoensis or 

Festuca idahoensis – Pseudoroegneria spicata; and 5) Festuca scabrella

(Daubenmire 1970, pp. iii-iv; Mueggler and Stewart 1980, p. 5; Tisdale 1986b, 

pp. 16-18; Johnson and Simon 1987, pp. 29-31). Primary shrub habitats include: 

1) Artemisia tridentata (big sagebrush) – Festuca idahoensis; and 2) Artemisia 

tripartita (three-tip sagebrush) – Festuca idahoensis. Primary forest habitat types 

include: 1) Pinus ponderosa (ponderosa pine) – Festuca idahoensis; and 2) Pinus 

ponderosa – Symphoricarpos albus. In 2004, 73 percent of known Silene 

spaldingii occurrences are within grassland habitat types, 20 percent within shrubsteppe habitat types, and 7 percent within forest habitat types (summarized by Hill 

and Gray 2004a, p. 37). Although the recent discovery of several new sites in the 

shrub-steppe of the Canyon Grasslands significantly increases the number of 

plants and sites in this habitat type. Some of the most difficult nonnative invasive 

plants to control in Silene spaldingii habitat include Cardaria draba (whitetop), 

Centaurea maculosa (spotted knapweed), Centaurea solstitialis (yellow 

starthistle), Chondrilla juncea (rush skeletonweed), Euphorbia esula (leafy 

spurge), Hypericum perforatum (St. Johnswort), Linaria dalmatica (Dalmatian 
Recovery Plan for Silene spaldingii ● September 2007 

21 

toadflax), Poa pratensis (Kentucky bluegrass), and Potentilla recta (sulfur 

cinquefoil). 

We have split the occupied habitat of Silene spaldingii into five 

physiographic regions that are characterized by distinctive physical features. 

These regions are distinctive from one another in climate, plant composition, 

historical fire frequencies, and soil characteristics. These differences are 

significant in that they may translate into differences in life histories, habitat 

trends, consequences of fire suppression, and types of weed control as they apply 

to conservation of S. spaldingii. The five physiographic regions utilized in this 

recovery plan are: 

1. the Blue Mountain Basins in northeastern Oregon; 

2. the Canyon Grasslands along the Snake, Salmon, Clearwater, Grande 

Ronde, and Imnaha Rivers in Idaho, Oregon, and Washington; 

3. the Channeled Scablands of east-central Washington; 

4. the Intermontane Valleys of northwestern Montana; and 

5. the Palouse Grasslands in southeastern Washington and adjacent westcentral Idaho. 

These regions are shown in Figure 4 above, and were delineated by taking 

the physiographic regions from Hill and Gray (2004a, Figure 3a) and relating the 

regions to the more widely used Level IV Ecoregions for each state (U.S. 

Environmental Protection Agency 2004, p. 1). The only S. spaldingii populations 

that did not fit well into the regions characterized in Figure 4 were those on Clear 

Lake Ridge in Oregon and those at Lost Trail National Wildlife Refuge in 

Montana. The Clear Lake Ridge populations will be included with the Blue 

Mountain Basins here instead of the Canyon Grasslands, as pictured in Figure 4, 

and the Lost Trail populations are included within Montana’s Intermontane 

Valleys. 

Of the five physiographic regions where Silene spaldingii is found, the 

habitat of the Canyon Grasslands is the most intact, largely because the canyon 

walls are steep and do not lend themselves to agricultural or urban developments. 

The Canyon Grasslands range widely in elevation, as evidenced by the presence 

of Hells Canyon, the deepest canyon in the United States at a depth of 2,400 

meters (7,900 feet; Alt and Hyndman 1989, p. 193). The dramatic range in 
Recovery Plan for Silene spaldingii ● September 2007 

22 

elevation within the Canyon Grasslands results in marked variations in the climate 

and vegetation. Soils within the Canyon Grasslands range from solid bedrock 

cliffs to deep loess and ash deposits (Alt and Hyndman 1989, p. 175). 

Within the Canyon Grasslands, Silene spaldingii is found at the lowest and 

highest elevations rangewide from 365 to 1,615 meters (1,200 to 5,300 feet) 

(ICDC 2007; summarized in USFWS 2007), generally on northerly slopes that 

support more mesic Festuca idahoensis communities. At higher elevations (over 

approximately 1,525 meters [5,000 feet]) in the Canyon Grasslands the northern 

slopes are inhabited by tree species and S. spaldingii is found on southern slopes 

where bunchgrass communities reside. Because of their steep topography, the 

Canyon Grasslands are the most undersurveyed area for S. spaldingii, and also 

represent the area where large populations of S. spaldingii may be most easily 

conserved because they are more removed from human influence. 

The Channeled Scablands are similar to the Palouse Grasslands with an 

underlying basalt layer covered by deep deposits of loess and ash, forming long 

undulating dune-like plains of rich soils; except that massive flooding, associated 

with bursting ice dams in the last ice age 12,000 to 16,000 years ago, has scoured 

portions of the area (Mueller and Mueller 1997, p. 29). This scouring has created 

a network of various habitats (loess islands surrounded by flood channels) that is 

far less consistent than the deep soil deposits of the Palouse Grasslands. Soils 

vary from basalt bedrock outcroppings to fertile loess and ash deposits to flood 

deposits (Daubenmire 1970, p. 6). An interesting landscape feature of the 

Channeled Scablands is referred to as “biscuit and swale” topography, commonly 

used to describe small biscuit-like loess mounds that are 1 meter deep by 5 meters 

in diameter (3 feet deep by 15 feet in diameter) and are regularly dispersed over 

scablands or bare tracts of basalt outcrops (Daubenmire 1970, pp. 6-7). Like the 

Palouse Grasslands, the large loess islands that remain in the Channeled 

Scablands are fertile and consequently have been largely converted to agriculture. 

The forested portion of the Channeled Scablands is a mosaic of forest / non-forest, 

and S. spaldingii plants occur in the non-forested microsites. 

Silene spaldingii is reported to be primarily associated with relict flood 

channels within the Channeled Scablands (see Figure 4). More specifically, S. 

spaldingii is generally found on northern facing slopes below talus or rock 

outcroppings, gentle northern slopes just above valley floors, or on the northern 
Recovery Plan for Silene spaldingii ● September 2007 

23 

sides of biscuits (B. Benner, U.S. Bureau of Land Management [USBLM], in litt.

1993, pp. 1-5). The species is found at elevations from 472 to 747 meters (1,550 

to 2,450 feet) within the Channeled Scablands. Since we lack earlier botanical 

surveys, we do not know how much S. spaldingii may have formerly occurred 

within the loess islands between channels. However, its affinity for deep soils 

elsewhere indicates that habitat conversion has most likely reduced the number of 

plants found on these loess islands. 

The Intermontane Valleys of northwestern Montana were glaciated more 

heavily than any other part of Montana. The valleys have been shaped by glacial 

activity associated with the continental ice sheet and the formation of Glacial 

Lake Missoula during the last ice age (Alt and Hyndman 1986, pp. 50-54). 

Topography in this region is characterized as “kettle and moraine.” Kettles are 

steep-sided hollows without surface drainage and moraines are earth and stone 

deposits; both are formed by glacial flows. 

Silene spaldingii populations within Montana are disjunct (separated by 

well over 160 kilometers [100 miles]) from S. spaldingii sites elsewhere. Plants 

have only been found near Eureka on the Tobacco Plains, in the Niarada and 

Flathead Lake area, and, most recently, on the Lost Trail National Wildlife 

Refuge. The species is found at elevations from 820 to 1,150 meters (2,700 to 

3,800 feet) within the Intermontane Valleys. S. spaldingii is found in small 

isolated grasslands outside the larger valleys delineated in Figure 4, demonstrated 

by the recent discoveries at the Lost Trail National Wildlife Refuge. Within 

Montana, Festuca idahoensis is codominant or subdominant with Festuca 

scabrella, sometimes near the forest’s edge. 

The Palouse Grasslands, as delineated here (Figure 4), are extremely 

fertile and may comprise the world’s best wheat land (Alt and Hyndman 1989, p. 

190). An underlying basalt layer is covered with deep deposits of loess and ash, 

forming long undulating dune-like plains of rich soils. These soil deposits can 

reach depths of 105 to 140 meters (350 to 450 feet), although generally less 

(Mueller and Mueller 1997, p. 25), and have high moisture-holding capacity and 

water infiltration rates (Johnson and Simon 1987, p. 8). Occasionally tall granitic 

hills (“steptoes”) protrude above the undulating dunes. Beginning in 1880, the 

Palouse Grasslands have undergone a dramatic conversion to farm lands; it is 

estimated that today only 0.1 percent of the grasslands remain in a natural state 
Recovery Plan for Silene spaldingii ● September 2007 

24 

(Noss et al. 1995, p. 2). The remains of the Palouse Grasslands include small 

remnants in rocky areas or at field corners (Daubenmire 1970, p. 1; Tisdale 

1986a, p. 206). The Camas Prairie in Idaho between the Clearwater and Salmon 

Rivers is included with the Palouse Grasslands here because soil properties and 

land conversions are similar; however, the Camas Prairie is generally higher in 

elevation and cooler and moister than other portions of the Palouse Grasslands 

(Ertter and Moseley 1992, p. 62; Lichthardt and Moseley 1997, p. 5). 

Silene spaldingii within the Palouse Grasslands is restricted to small 

fragmented populations (“eyebrows4

,” field corners, cemeteries, rocky areas, and 

steptoes) on private lands, and in larger remnant habitats such as research lands 

owned by Washington State University. Elevations occupied by S. spaldingii

within the Palouse Grasslands range from 700 to 1,340 meters (2,300 to 4,400 

feet). Of all the places where S. spaldingii resides, those in the Palouse 

Grasslands are the most threatened, and care is needed to maintain occupied sites 

and representative genetic material from these sites. 

The Blue Mountain Basins were once contiguous Pacific Northwest 

Bunchgrass Grasslands. Today much of the Wallowa Valley has been converted 

into residential or urban areas surrounded by agricultural and grazing lands. Soils 

are composed of deep loess similar to the Palouse Grasslands or glacial till soils 

such as those at the head of Wallowa Lake. 

Silene spaldingii ranges from 1,130 meters (3,700 feet) to 1,555 meters 

(5,100 feet) within the Blue Mountain Basins, specifically the Wallowa Valley 

(ONHP 2006, pp. 10, 14). The basin abuts habitat characterized as Canyon 

Grasslands, with no clear demarcation between the two regions. In the Blue 

Mountain Basins, S. spaldingii is often found along slopes of low broad ridges 

and ridgebrows, some with biscuit and swale topography (Hill and Gray 2004a, p. 

25). Within the Wallowa Valley, habitat is highly dissected by urban and 

agricultural lands. A large S. spaldingii population (over 500 individuals) occurs 

at the end of Wallowa Lake. This population is the largest occurring on private 

land, other than land owned by The Nature Conservancy, and is threatened by 

urban development. 

 

4

 “Eyebrows” are patches of prairie that occur along rocky ridges that were too steep to farm. 

They appear as “eyebrows” on the landscape because they have more vegetation than the 

surrounding farmlands. 
Recovery Plan for Silene spaldingii ● September 2007 

25 

Rangewide suitable habitat for Silene spaldingii would include all flat, 

east facing, northern facing, and even southern facing (at higher elevations) slopes 

between 365 to 1,615 meters (1,200 to 5,300 feet) in elevation within Festuca 

idahoensis and Festuca scabrella communities that are associated with Pacific 

Northwest bunchgrasses, sagebrush-steppe, and open pine forests. However, even 

within what is presently understood to be suitable habitat, S. spaldingii is quite 

infrequent (rare). If another habitat parameter was identified that would help to 

narrow the definition of suitable habitat for this species, field searches could 

become more focused. At present it appears that there are tracts of suitable 

habitat for S. spaldingii on private and public lands within the Canyon Grasslands, 

Channeled Scablands, and the Blue Mountain Basins. Identifying a mechanism to 

help facilitate searches on these lands may identify other large populations where 

conservation efforts could occur. There is little remaining habitat within the 

Palouse Grasslands, limiting the possibilities of finding significant new S. 

spaldingii populations. Within the Intermontane Valleys there are large areas of 

apparently suitable habitat, but much of it has been searched, and it is thought that 

new discoveries of populations with over 1,000 individuals are unlikely 

(P. Lesica, in litt. 2006, p. 2). 

F. ASSOCIATED SPECIES OF CONSERVATION CONCERN

Rare animal species that occur within the range of Silene spaldingi include 

the Columbian sharp-tailed grouse (Tympanuchus phasianellus columbianus). 

Rare endemic plant species include Aster jessicae (Jessica’s aster), Astragalus 

riparius (Piper’s milk-vetch), Calochortus macrocarpus var. maculosus (greenband mariposa lily), Calochortus nitidus (broad-fruit mariposa), Cirsium 

brevifolium (Palouse thistle), Polemonium pectinatum (Washington polemonium), 

Pyrrocoma liatriformis (Palouse goldenweed), Rubus nigerrimus (Northwest 

raspberry), and Trifolium plumosum var. amplifolium (plumed clover) (Hill and 

Gray 2004a, Tables 9-12A). Many of these species face the same impacts as does 

S. spaldingii and some are more restricted in distribution. Conservation activities 

implemented through this recovery plan should, whenever possible, include 

measures for conservation of the rare species listed above. 
Recovery Plan for Silene spaldingii ● September 2007 

26 

G. REASON FOR LISTING/THREATS ASSESSMENT

Section 4(a)(1) of the Endangered Species Act identifies five factors or 

categories of threats that are considered when making listing, delisting, or 

reclassification decisions. In the narrative threat assessment that follows, we have 

classified the threats to Silene spaldingii according to these five factors, which are 

as follows: 

 

Factor A ⎯ The present or threatened destruction, modification, or 

curtailment of habitat or range; 

Factor B ⎯ Overutilization for commercial, recreational, scientific, or 

educational purposes; 

Factor C ⎯ Disease or predation; 

Factor D ⎯ The inadequacy of existing regulatory mechanisms; and 

Factor E ⎯ Other natural or man-made factors affecting the continued 

existence of a species. 

1. Invasive Nonnative Plants (Factor A) 

 Invasive nonnative plants (weeds) are called the “silent invaders” because 

they subtly invade and alter diverse native communities into nonnative plant 

monocultures that support little wildlife. For example, in Idaho over the last 30 

years, Centaurea solstitialis (yellow starthistle) has increased from a few small 

patches to 120,000 hectares (300,000 acres) (Westbrooks 1998, p. 3). Since the 

1960s, Chondrilla juncea (rush skeletonweed) has expanded in Idaho from 16 

hectares (40 acres) to more than 1,600,000 hectares (4,000,000 acres) 

(Westbrooks 1998, p. 3). Centaurea maculosa (spotted knapweed) is considered 

to be “the number one weed problem on rangeland in western Montana” (Whitson 

et al. 1996, p. 89) and has infested more than 1,900,000 hectares (4,700,000 

acres) in the State (Westbrooks 1998, p. 4). In southeastern Washington, 

Centaurea solstitialis has increased from 400 hectares (1,000 acres) in 1954 to 

more than 56,650 hectares (140,000 acres) (Westbrooks 1998, p. 8). 

Many experts believe that following habitat destruction, invasive 

nonnative plants are the next greatest threat to biodiversity (Randall 1996, p. 370). 

Nonnative plant invasions have been identified by numerous individuals working 

with S. spaldingii as one, if not the largest, of the threats facing the species and its 
Recovery Plan for Silene spaldingii ● September 2007 

27 

habitat (Hill and Gray 2004a, p. 100). Invasive nonnative plants alter different 

attributes of ecosystems including geomorphology, fire regime, hydrology, 

microclimate, nutrient cycling, and productivity (for a good summary see Dukes 

and Mooney 2004). 

Invasive nonnative plants detrimentally affect native plants through 

competitive exclusion, altering pollinator behaviors, niche displacement, 

hybridization, and changes in insect predation; examples are widespread among 

taxa and locations or ecosystems (D’Antonio and Vitousek 1992, pp. 65-66, 68-

71; Olson 1999 p. 2, 7-11; Mooney and Cleland 2001, pp. 6-9). Rare plants with 

already small and fragmented populations can be particularly vulnerable to 

adverse effects from invasive nonnative plants. For example, invasive nonnative 

annual grasses (including Bromus spp.) significantly increased mortality and 

decreased survivorship, plant size, and reproductive output in an endangered 

annual herb (Amsinckia grandiflora [large-flowered fiddleneck]) (Pavlik et al.

1993, p. 520). In another study, Huenneke and Thomson (1995, p. 423) found 

that competition from Dipsacus sylvestris = Dipsacus fullonum ssp. sylvestris

(teasel), an invasive nonnative plant, negatively affected growth and seedling 

recruitment in the threatened Cirsium vinaceum (Sacramento Mountains thistle). 

In Montana, Lesica and Shelly (1996, p. 118) found that Centaurea maculosa

reduced recruitment and population growth of the rare Arabis fecunda (Mt. 

Sapphire rockcress). Rangelands throughout the range of S. spaldingii have been 

broadly affected by nonnative plant invasions, with consequent effects upon 

community composition, resource availability, pollinator dynamics, and fire 

frequency. The effects of invasive nonnative plants on S. spaldingii have been 

addressed qualitatively by a few studies as discussed below, but further research 

is needed to determine details of how invasive plants may affect the demography 

of S. spaldingii populations at different life stages and which invasive species 

pose the most significant threat. 

Annual invasive nonnative grasses co-occur with Silene spaldingii at most 

populations and pose a threat to the species in most locations except northwest 

Montana where annual grass invasions are not as prolific. The annual invasive 

grasses are most commonly represented by Bromus japonicus (Japanese brome), 

Bromus secalinus (cheat), Bromus tectorum (cheatgrass), and Ventenata dubia

(ventenata) (Hill and Gray 2004a, pp. 67-69). Bromus tectorum, for example, has 

contributed to the widespread degradation of native rangelands throughout the 
Recovery Plan for Silene spaldingii ● September 2007 

28 

western United States. Due to its ability to germinate readily under a wide variety 

of environmental conditions, Bromus tectorum is extremely difficult to eradicate 

once established in native plant communities (Franklin and Dyrness 1988, p. 211). 

In rangelands that are dominated by Bromus tectorum, seedling establishment of 

native perennial species may be limited by Bromus tectorum’s ability to compete 

for moisture (Young 1994). And most significantly, invasive nonnative grasses 

alter natural fire regimes (D’Antonio and Vitousek 1992, p. 72-77; see Section G3). 

Rhizomatous5 invasive nonnative plants, because of their deep and 

extensive root systems, are the most difficult invasive nonnative plants to remove 

from Silene spaldingii habitat, often requiring persistent herbicides for control. 

Persistent herbicides, such as picloram products, remain in the soil longer where 

they may be transported and affect non-target plant species (Cox 1998, pp. 17-

18), such as S. spaldingii. Co-occurring rhizomatous species include Acroptilon 

repens (Russian knapweed), Chondrilla juncea (rush skeletonweed), Cirsium 

arvense (Canada thistle), Euphorbia esula (leafy spurge), Hypericum perforatum

(St. Johnswort), Linaria dalmatica (Dalmatian toadflax), and Poa pratensis

(Kentucky bluegrass) (Hill and Gray 2004a, pp. 67-70). 

Like the invasive nonnative annual grasses, a common strategy employed 

by invasive nonnative plants is to produce copious quantities of seeds. These 

species are difficult to control because seeds are capable of quickly spreading to 

new S. spaldingii habitats. Prolific seeding invasive nonnative plants found 

within or near S. spaldingii include Acroptilon repens, Centaurea solstitialis, 

Centaurea diffusa (diffuse knapweed), Centaurea maculosa, Chondrilla juncea, 

Dipsacus sylvestris (teasel), Hypericum perforatum, and Potentilla recta (Hill and 

Gray 2004a, p. 67). Some of these species are also rhizomatous, making them 

doubly difficult to control. 

 Some of these invasive nonnative plants can invade and displace native 

plant communities in a relatively short period of time. For example, at Garden 

Creek Ranch, the largest Silene spaldingii population in Idaho (ICDC 2007, 

Element Occurrence 005; summarized in USFWS 2007), Centaurea solstitialis

spread from approximately 60 hectares (150 acres) in 1987 to 810 hectares (2,000 

 

5

 “Rhizomatous” plants have rhizomes, horizontal underground stems with leaves and buds that 

serve as a means of vegetative propagation. Such plants are particularly difficult to eradicate, as 

the rhizomes (and thus the plant) often survive most traditional methods of plant removal. 
Recovery Plan for Silene spaldingii ● September 2007 

29 

acres) in 1998 (J. Hill, in litt. 1999, p. 3; Hill and Gray 1999, p. 100 ). Another 

roadside S. spaldingii site in Idaho (Lawyer’s Creek) was apparently extirpated as 

a result of the disturbance caused by highway construction in 1990 and the 

subsequent invasion of Centaurea solstitialis (Lichthardt 1997, p. 7). 

Centaurea solstitialis is found in the vicinity of all Silene spaldingii 

populations in Idaho (Lichthardt 1997, p. 12). This aggressive and invasive 

nonnative plant can form almost complete monocultures, invading and 

outcompeting native species. Even small areas that experience soil disturbance 

are almost immediately colonized by Centaurea solstitialis or other invasive 

nonnative winter annuals (Lichthardt 1997, p. 12). The seeds of Centaurea 

solstitialis can remain dormant in the soil for 10 years (Callihan and Miller 1997, 

p. 59), making effective control of this invasive nonnative plant difficult. 

Originally it was thought that Centaurea solstitialis only invaded southerly and 

flat aspects, and that it could not invade northerly slopes because of limited light 

during winter months (Roché 1965). However, in recent years Centaurea 

solstitialis has invaded several northern slopes that support S. spaldingii in the 

Canyon Grasslands (Hill and Gray 2000, p. 14) and may be expanding its 

ecological amplitude. 

 A 2-year study investigating the effects of invasive nonnative plants, such 

as Centaurea solstitialis, on Silene spaldingii at Garden Creek Ranch did not find 

any appreciable differences in plant vigor between invaded and uninvaded sites 

(Menke 2003, p. 35). However, most S. spaldingii individuals in this study were 

at least 2 meters (6.5 feet) away from Centaurea solstitialis and Bromus tectorum

infestations and may not have experienced significant competition. The 

researcher proposed that mature S. spaldingii individuals and the invasive 

nonnative plants may also partition resources differently in space or time; effects 

of invasive nonnative plants upon recruitment of S. spaldingii seedlings are 

potentially important to population viability but were not measured in this study. 

Another study found that high levels of invasive nonnative plant cover 

(predominantly Bromus secalinus, Hypericum perforatum, and Ventanata dubia) 

were associated with less vigorous occurrences of S. spaldingii at the Fairchild 

Air Force Base in Washington (Caplow 2002a, p. 8). Further research is needed 

on the specific effects of nonnative plant invasions upon S. spaldingii. 
Recovery Plan for Silene spaldingii ● September 2007 

30 

 Competition with other plant species for a limited number of pollinators, 

particularly competition with invasive nonnative plants, has the potential to 

adversely affect both fecundity and individual fitness in S. spaldingii (Lesica and 

Heidel 1996, p. 10). These deleterious effects occur: (1) when insects switch 

from one plant species to another resulting in a transfer and loss of pollen to a 

second species, and (2) because insects will demonstrate preferences for plant 

species (including invasive nonnative plants) where resources are more easily 

obtained. That is, either a plant species is more abundant or the resources (pollen 

and nectar) a plant provides are more nutritive (Richards 1997, p. 148-152). For 

example, investigations have found visitation rates of the bumblebee Bombus 

fervidus are lower for S. spaldingii when it co-occurs with the invasive nonnative 

Hypericum perforatum (Lesica and Heidel 1996, p. 10). 

Nonnative grasses such as Agropyron cristatum and A. desortum (crested 

wheatgrass), Bromus inermis (smooth brome), and Poa pratensis are used in 

rangeland revegetation within Silene spaldingii habitat. These grasses are used 

because they are broadly-adapted, widely available as seed, establish easily, are 

grazing tolerant, and provide competitive invasive nonnative plant control. 

Rangeland revegetation focuses on providing forage for livestock, erosion control, 

and watershed rehabilitation. However, there is an increasing body of research 

that demonstrates these nonnative grasses, in some instances, can decrease 

biodiversity and compete with native plants (summarized by Harrison et al. 1996, 

see especially Poa pratensis). For example, Agropyron cristatum stands in 1966 

in southern Idaho had already persisted for 30 to 50 years and were spreading into 

adjacent habitats (Hull and Klomp 1966, p. 10; 1967, p. 226). Other studies have 

also found nonnative planted grasses invading adjacent native communities 

(D’Antonio and Vitousek 1992, pp. 69-70). In one study, a Snake River Plain 

endemic, Lepidium papilliferum (slickspot peppergrass) had decreased abundance 

in areas that had been planted with Agropyron cristatum (Scholten and Bunting 

2001, p. 5-6). The planting of nonnative range grasses is thought to have 

eliminated habitat for S. spaldingii in several locations across its range (Hill and 

Gray 2004a, pp. 64-65), particularly in the Channeled Scablands (B. Benner, in 

litt. 1993, p. 5; B. Weddell, Draba Consulting, in litt. 2003, p. 6; WNHP 2007). 

Nonnative grasses are being planted at Corral Creek, near S. spaldingii sites in 

Idaho, and spreading along road corridors (K. Gray, ICDC, in litt. 2004, p. 3). 
Recovery Plan for Silene spaldingii ● September 2007 

31 

There is considerable discussion on how best to restore degraded sites 

within the arid West (Lesica and Allendorf 1999, Jones 2003, Roundy 2005). We 

recognize that native species may be more difficult to obtain and costly, and that 

successful invasive nonnative plant control and restoration with native species can 

be more difficult on arid sites or sites adjacent to invasive nonnative sites 

(Roundy 2005, p. 48). The use of nonnative restoration species and competition 

with rare species is not well understood. But, the examples in the preceding 

paragraph illustrate that caution is needed. For these reasons, nonnative 

restoration species should not be used for restoration near S. spaldingii sites 

unless previous greenhouse studies have shown that the nonnative restoration 

species will not compete with S. spaldingii. 

2. Problems Associated with Small, Geographically Isolated 

Populations (Factors A, E) 

Most populations of Silene spaldingii are restricted to small, remnant 

patches of native habitat (Gamon 1991, p. 16; Lichthardt 1997, p. 8; Hill and Gray 

2004a, pp. 61-64; ONHP 2006; ICDC 2007; MNHP 2007; WNHP 2007). If 

populations are defined by grouping together sites within 1.6 kilometers (1 mile) 

of one another (a long distance for pollen transfer), there are 99 known 

populations of S. spaldingii. Of these 99 populations, 56 (57 percent) have fewer 

than 50 plants, and another 10 populations have 100 or fewer individuals, 

meaning that 67 percent of the populations have 100 or fewer individual plants 

overall (Figure 5) (summarized in USFWS 2007). Many of these small remnant 

populations exist within habitat that is generally further degraded by one or more 

of the threats listed here. Many S. spaldingii populations are isolated from other 

populations by large distances, and the majority occur at scattered localities 

separated by habitat that is not suitable for the species, such as agricultural fields. 

For example, extirpation appears to be certain for at least two isolated S. 

spaldingii populations in Idaho due to their small size and habitat degradation 

(Lichthardt 1997, p. 15). One of these populations consists of four individuals, 

and the other population has only one S. spaldingii plant. Even if the habitat was 

completely undisturbed, these populations would not be viable into the future. 

Small S. spaldingii populations have likely persisted due to prolonged dormancy 

and the relatively long life span of the plants, but the likelihood of future 

recruitment in these populations to replace senescent individuals is vanishingly 

small. 
Recovery Plan for Silene spaldingii ● September 2007 

32 

Figure 5. Known populations of Silene spaldingii.
Recovery Plan for Silene spaldingii ● September 2007 

33 

Small populations are vulnerable to relatively minor environmental disturbances 

such as fire, herbicide drift, and nonnative plant invasions (Barret and Kohn 1991, 

p. 7; Gamon 1991, p. 28) and are subject to the loss of genetic diversity from 

genetic drift and inbreeding (Ellstrand and Elam 1993, p. 218). Genetic drift, 

more prevalent in small populations, is the loss of genetic diversity through 

chance mating events. Inbreeding occurs when plants “self” (fertilization occurs 

within the same individual) or when closely related individuals mate, thereby 

reducing genetic diversity. Populations with lowered genetic diversity are more 

prone to local extinction (Barrett and Kohn 1991, p. 4). Smaller populations 

generally have lower genetic diversity, and lower genetic diversity may in turn 

lead to smaller populations by decreasing the species’ ability to adapt. Relatively 

low levels of genetic exchange (one migrant per generation) are generally 

considered sufficient to counteract the effects of genetic drift (Newman and 

Tallmon 2001, p. 1059).

Habitat fragmentation, similar to that which has occurred in the Palouse 

Grasslands and other habitats where S. spaldingii resides, has been documented as 

a problem for many rare species and even common species can be affected by 

habitat fragmentation (Honnay and Jacquemyn in press, p. 6). Often the 

fragments are not of sufficient size to support the natural diversity prevalent in an 

area (as summarized in Soulé 1987) and so exhibit a decline in native biodiversity 

(Noss and Cooperrider 1994, p. 52). Habitat fragments are often functionally 

smaller than they appear because edge effects impact the available habitat within 

the fragment (Lienert and Fischer 2003, p. 597), and intense agricultural practices 

will affect adjacent fragments (Boutin and Jobin 1998, p. 551). Habitat 

fragmentation has been shown to disrupt plant-pollinator interactions and 

predator-prey interactions (Steffan-Dewenter and Tscharntke1999, p. 437), and 

alter seed germination percentages (Menges 1991a, p. 160). Extensive habitat 

fragmentation, such as that seen in the Palouse Grasslands, can result in dramatic 

fluxes in available solar radiation, water, and nutrients (Saunders et al. 1991, pp. 

20-22). 

 There are numerous examples of habitat fragmentation affecting native 

plant species. Reduced seed set, reduced plant-to-plant variability, and lower 

pollination intensity in smaller populations was found for a small forest 

herbaceous plant, Primula elatior (oxlip) (Jacquemyn et al. 2002, p. 622). 
Recovery Plan for Silene spaldingii ● September 2007 

34 

Lowered seed germination percentages were found in smaller prairie fragments of 

Silene regia (royal catchfly) (Menges 1991a, pp. 161-162). Within a heavily 

utilized agriculturally fragmented area, Dianthus deltoides (maiden pink) 

exhibited lowered diversity and abundance of both flowering plants and flowervisiting insects, as well as lowered seed set attributed to lower numbers of 

available pollinators (Jennersten 1988, p. 364). Plants that were less capable of 

self-fertilization showed strongly reduced population viability with pronounced 

extinction thresholds at high levels of fragmentation (Lennartsson 2002, pp. 3065-

3067). This reduced population viability was attributed to inbreeding and reduced 

seed production as a result of low numbers of pollinators. 

 For plant populations that do not reproduce vegetatively, pollen exchange 

and seed dispersal are the only mechanisms for gene flow. Pollen exchange, 

because of the opportunity for more reliable and specific long distance dispersal, 

is thought to be the more important of these two mechanisms (Fenster 1991, pp. 

420-421; Richards 1997, p. 147). Pollen dispersal in species requiring an insect 

for pollination, such as Silene spaldingii, is limited by the distance the pollinator 

can travel, in this case probably less than 1.6 kilometers (1 mile); see previous 

discussion in section D. Life History/Ecology). Reduced pollinator activity has 

been correlated with lowered reproductive success and possibly reduced genetic 

diversity for S. spaldingii (Lesica 1993, p. 198; Lesica and Heidel 1996, p. 9; 

Baldwin and Brunsfeld 1995, p. 3). Populations of S. spaldingii occupying small 

areas surrounded by lands that do not support bumblebee colonies (e.g., crop 

lands) are not likely to persist over the long term (Lesica 1993, p. 199-200; Lesica 

and Heidel 1996, p. 11). In addition to agricultural conversion and pesticides, 

pollinators are vulnerable to plant herbicide applications, adverse domestic 

livestock grazing and trampling, and fire, and these potential impacts to 

pollinators must therefore be considered in conservation strategies for S. 

spaldingii (Gamon 1991, pp. 60-82; Lesica 1993, pp. 193, 199-200). 

3. Changes in the Fire Regime and Fire Effects (Factor A) 

Organisms adapt to disturbances such as historical fire regimes (fire 

frequency, intensity, and seasonality) with which they have evolved (summarized 

by Landres et al. 1999). Fire regimes within Silene spaldingii habitat in the 

western United States have been highly disrupted (Whisenant 1990, p. 4; 

D’Antonio and Vitousek 1992, pp. 74-75; Mutch et al. 1993, p. 2-4; Narolski 
Recovery Plan for Silene spaldingii ● September 2007 

35 

1996, pp. 5-6; Weddell 2001, p. 7; Hilty et al. 2004, p. 90). In some instances, 

fire suppression has allowed grasslands to be invaded by trees (Menges 1995, p. 

7; Lesica and Martin 2003, p. 517). At the same time, in many grassland and 

shrub habitats fire frequencies have increased because of annual nonnative grass 

and forb invasions (Whisenant 1990, p. 4; D’Antonio and Vitousek 1992, p. 73; 

Hilty et al. 2004, p. 90). These annual nonnative invasive grasses and forbs fill 

gaps that would naturally occur between vegetation, dramatically increasing the 

ability of fire to spread. Annual nonnative invasive grasses are common within S. 

spaldingii populations everywhere except northwestern Montana (Hill and Gray 

2004a, pp. 67-71, P. Lesica, in litt. 2006, p. 2). Seasonally, prescribed burns 

occur within S. spaldingii habitat during cool fall months as opposed to the hot 

summer months when fires would have historically burned (Hill and Gray 2004a, 

p. 58). 

The effect of fire on Silene spaldingii and its habitat has been investigated 

in two areas: the Intermontane Valleys at Dancing Prairie in Montana (Lesica 

1999; Lesica and Martin 2003) and the Canyon Grasslands at Garden Creek 

Ranch in Idaho (Hill and Fuchs 2003; Hill and Weddell 2003; Hill et al. 2001; 

Menke 2003; Hill and Gray 2004b; Menke and Muir 2004; Hill and Gray 2005b; 

Hill 2006; J. Hill, in litt. 2007a). Silene spaldingii and its habitat’s fire response 

at these two sites have some similarities, but also some major differences. Both 

the Montana and Idaho studies found S. spaldingii adults were not killed by fires 

(Lesica 1999, p. 999; Hill and Weddell 2003, p. 23; Menke 2003, p. 52, Table 3.4; 

Hill and Gray 2004b, p. 55). Fire apparently broke prolonged dormancy, so that 

apparent plant numbers were higher the year subsequent to a fire in both Idaho 

and Montana (Lesica 1999, p. 999; Hill and Fuchs 2003, p. 4; Menke 2003, pp. 

60-61), and more flowers were produced per plant after a fire (Lesica 1999, p. 

999; Hill and Weddell 2003, p. 21), although fewer of these flowers developed 

mature fruit (Menke 2003, p. 62). 

Study results differed between the sites in that in Montana, Silene 

spaldingii seedling recruitment was significantly higher after fire (Lesica 1999, 

pp. 998-999), whereas in Idaho it was not (Hill and Weddell 2003, p. 23; Hill and 

Gray 2004b, pp. 49, 55-58; Hill and Gray 2005b, p. 17; Hill 2006, p. 19). Several 

reasons may be responsible for this difference. First, habitat in Montana’s 

Intermontane Valleys differs in that more litter accumulates in the presence of 

Festuca scabrella (over 11 centimeters [4.3 inches]) as opposed to the Festuca 
Recovery Plan for Silene spaldingii ● September 2007 

36 

idahoensis-dominated grasslands in Idaho (1.3 centimeters [0.5 inch]) (Hill and 

Weddell 2003, p. 24; Hill and Gray 2004a, p. 57). Litter depth has been measured 

as deep as 20 centimeters (7.9 inches) at the Dancing Prairie Preserve in Montana 

(P. Lesica, in litt. 2007b). Greater litter depth may affect S. spaldingii seedling 

recruitment because it is difficult for seedlings to germinate under and grow 

through a dense litter layer (Lesica 1999, p. 1000). Second, the year after the 

experiment in Montana with experimental burns was one of the few years with 

significant recruitment in both burned and unburned areas (Lesica 1999, Figure 1; 

P. Lesica, in litt. 2006, p. 3; Lesica and Crone in review, Figure 1). Third, criteria 

for classifying rosette plants as adults or seedlings vary between the two studies 

(J. Hill, in litt. 2007b, p. 7). While fire appears necessary for maintaining 

grasslands and preventing tree and shrub encroachment in Montana (Lesica 1999, 

p. 997 and 1001), it may not be important in maintaining the drier grasslands 

within the Canyon Grasslands or Palouse Grasslands where a lack of moisture 

(Daubenmire 1968, p. 438; Daubenmire 1970, p. 8; Tisdale 1986a, p. 2; Weddell 

2001, p. 27) is thought to have precluded tree and shrub invasion. Some think 

that the upper elevation grasslands in the Canyon Grasslands may need fires to 

prevent tree encroachment. 

Nonnative plant invasions are affected by fires, both natural and 

prescribed, within Silene spaldingii habitat. Lesica and Martin (2003, p. 520) 

found that the nonnative invasive plant Potentilla recta (sulfur cinquefoil) at 

Dancing Prairie in Montana demonstrated the highest recruitment within burned 

plots, although this recruitment did not translate to increased population growth. 

Also, fire seemed to reduce the efficacy of herbicide treatments on killing P. 

recta. One study at Garden Creek Ranch in Idaho found that monitoring plots 

established on either side of a fire line in very good-condition Festuca idahoensis 

habitat had significant increases in the frequency, basal cover, and density of both 

the nonnative plants Centaurea solstitialis (yellow starthistle) and Bromus

japonicus (Japanese brome) in burned versus unburned plots 2 years after a burn 

(Hill et al. 2003, p. 2). Another found more invasive nonnative plants at higher 

densities or cover in burned versus unburned sites 2 years after a burn (Hill and 

Weddell 2003, p. 24). Conversely, another study in Idaho found decreased cover 

of the native Festuca idahoensis, an increase in the native forb Lupinus sericeus

(silky lupine), and a constant cover in the native Pseudoroegneria spicata

(bluebunch wheatgrass), exotic grasses, and other forb species 2 years after a fire 

(Menke 2003, p. 56). At one site in Washington, a prescribed burn escaped in 
Recovery Plan for Silene spaldingii ● September 2007 

37 

1997, burning S. spaldingii plants and habitat. Although the native bunchgrasses 

rebounded nicely, nonnative annual grasses are now dominant, opening the site to 

invasion by adjacent Centaurea solstitialis populations (J. Wood, U.S. Forest 

Service, in litt. 2004). Thus invasive nonnative plants, as a result of fire, may 

deleteriously affect S. spaldingii (see the discussion of “Invasive Nonnative 

Plants,” Section G-1, above). 

The season or timing of fire has been shown to affect Silene spaldingii and 

its habitat. Lesica (1999, Figure 1, pp. 1000-1001) found that fall burning led to 

lower seedling recruitment for S. spaldingii than spring burning, and these effects 

continued to be apparent for 2 to 3 years after the burns. Most natural fires within 

S. spaldingii’s range would have historically occurred during the dry summer 

months, while today prescribed burning occurs during the cooler months when 

fires are more easily controlled. More studies are needed investigating the timing 

of both natural and prescribed burns and their effects on S. spaldingii and its 

habitat. 

 Management activities often seek to mimic historical fire regimes 

(Landres et al. 1999). Within forested stands, historical fire frequencies are 

relatively easy to establish by examining burn scars in tree rings. Establishing 

historical fire frequencies within grasslands is significantly more difficult because 

of the lack of trees to provide a physical record (P. Morgan, University of Idaho, 

in litt. 2007, p. 1). For example, within the Canyon Grasslands estimates of 

historical fire frequencies range widely, from every 6 to every 25 years (U.S 

Bureau of Land Management 2001, p. 39; J. White, Idaho Department of Fish and 

Game, pers. comm. 2003, p. 1), to infrequently (Weddell 2001, p. 7). Weddell 

(2001, p. 7) argued that there is little specific data on the historical fire frequency 

of these grasslands, and that fire has damaging effects on two dominant 

bunchgrasses, Festuca idahoensis and Hesperostipa comata = Stipa comata

(needle-and-thread grass), as well as on the microbiotic crusts commonly 

associated with Silene spaldingii that recover slowly after fire. 

 Regardless of the accuracy of fire frequency data, Silene spaldingii does 

appear to be able to tolerate some fire (Lesica 1999, p. 1000; Hill and Fuchs 2003, 

p. 3; Hill and Weddell 2003, p. 23; Menke 2003, p. 60). The effects of fires will 

vary at different S. spaldingii sites due to factors such as fuel moisture content, 

species composition, and season and intensity of burning (Lesica and Martin 
Recovery Plan for Silene spaldingii ● September 2007 

38 

2003, p. 521). For example, burning while the plant is germinating or seeding 

will likely negatively affect reproduction. Most importantly, prescribed burning 

should not occur where invasive nonnative plants reside, since the establishment 

of these disturbance-adapted species can be promoted by fire (Christensen and 

Burrows 1986, pp. 100-101; Hobbs and Huenneke 1992, p. 327; Lesica and 

Martin 2003, p. 521), unless very careful weed control and monitoring will occur 

prior to and after the prescribed burn. 

4. Land Conversion Associated with Urban and Agricultural 

Development (Factor A) 

 Extensive land conversion has already occurred on private lands across the 

range of Silene spaldingii, and 32 known populations of S. spaldingii (32 percent) 

occur entirely on privately owned lands, with an additional 18 populations (18 

percent) in partial private ownership (USFWS 2007). These populations are 

currently affected by changes in land use practices, including adverse livestock 

grazing and trampling, agricultural developments, and urbanization. Most 

surveys on private lands have been preliminary and occurred only once, often 

over 15 years ago, so it is difficult to know exactly how large or what impacts 

may be occurring at these populations. Rural population growth has increased 

over the last 2 decades in all counties where S. spaldingii resides (Hill and Gray 

2004a, p. 62). Population growth is expected to continue in all areas where S. 

spaldingii resides, especially near urban areas. In addition to direct loss of S. 

spaldingii populations affected by urban and agricultural development, there are 

also indirect effects including the problems associated with small, geographically 

isolated populations (see 2 above) and an increased opportunity for impacts from 

invasive nonnative plants that are brought in with associated disturbances. For 

example, invasive nonnative plants frequently are spread along road corridors 

(Gelbard and Belnap 2003). 

 Active housing developments threaten to eliminate Silene spaldingii

habitat near Redbird Ridge in Idaho (Lichthardt 1997, p. 12). Unsurveyed 

residential development immediately adjoining the Dancing Prairie Preserve 

owned by The Nature Conservancy in Montana, which has the largest S. 

spaldingii population rangewide, has destroyed potential habitat, increased the 

likelihood of nonnative plant invasions, and reduced management options such as 

controlled burning on the preserve (B. Martin, The Nature Conservancy of 
Recovery Plan for Silene spaldingii ● September 2007 

39 

Montana, in litt. 1998, p. 1). Continued development in this area is expected (B. 

Martin, in litt. 1998, p. 1). Recently, one population (Element Occurrences 003 

and 004) in Montana was acquired by the Montana Large Animal Sanctuary and 

Rescue. Since this time, the area has been utilized for heavy grazing, noxious 

weeds have proliferated, and no plants were located in either 2003 or 2004. This 

population is considered “possibly extirpated” by the Montana Natural Heritage 

Program (Mincemoyer 2005, p. 8). The continuing fragmentation of suitable 

habitat and possible loss of the Tobacco Plains (now called the Roosville) area is 

anticipated (Mincemoyer 2005, p. 15). S. spaldingii on private land near Wallowa 

Lake in eastern Oregon, one of the 10 sites with over 500 individuals, may be 

threatened by development (ONHP 2006, Element Occurrence 10). Other S. 

spaldingii sites on private land in Idaho, Montana, and Washington are also 

threatened by development. 

One Silene spaldingii site within Idaho is near an active gravel pit 

operation. Expansion of this gravel pit may be planned in the near future in 

association with a highway expansion project (G. Glenne, USFWS, in litt. 2004, 

p. 1). Although the S. spaldingii site will remain intact, disturbances associated 

with the gravel operation may increase the chance for nonnative plant invasions. 

In addition, dust has been shown to affect the energy and nutrient gathering 

processes of vegetation differentially, subsequently altering community 

composition (Farmer 1993, pp. 66-69). 

5. Adverse Livestock Grazing and Trampling (Factors A, C) 

Sufficient research has not been completed to determine exactly what 

effects adverse livestock grazing and trampling is having on Silene spaldingii. 

Adverse livestock grazing and trampling has occurred within S. spaldingii’s range 

for over 150 years (Mack 1981, p. 4). The relatively long life span of this 

herbaceous perennial and its long taproot has likely helped S. spaldingii withstand 

some adverse livestock grazing and trampling impacts. Without good historical 

population number estimates for comparison from the time prior to the initiation 

of livestock use, it is difficult to assess trends over time. Instead shorter term, 

more evident losses such as loss of reproductive structures, individuals, and 

habitat degradation are used to infer an impact to S. spaldingii from adverse 

livestock grazing and trampling. It has been suggested that under careful 

management livestock grazing has the potential to have no effect or positively 
Recovery Plan for Silene spaldingii ● September 2007 

40 

affect S. spaldingii by reducing litter in areas where it accumulates to the 

detriment of S. spaldingii and fire is not an option (P. Lesica, in litt. 2006, p. 3). 

Adverse livestock grazing and trampling is the most contentious management 

issue within the range of S. spaldingii with critics and supporters (see Curtin 

2002, p. 240). 

Livestock grazing directly affects Silene spaldingii by the removal of 

flowers and/or seeds, thereby limiting reproduction for that season (G. Glenne, in 

litt. 2003, p. 2). Most all life history stages contribute to population growth; 

however, for perennial herbaceous species, adult survival from one year to the 

next has been shown to be more important to population growth than fruit 

production (Silvertown et al. 1993, p. 472; Crone 2001, p. 2613), and Lesica 

(1997, p. 356) found that survival of S. spaldingii while dormant was most critical 

to population growth of this species. Livestock trampling may also affect S. 

spaldingii by destroying seedlings or breaking the root caudex6

, potentially killing 

the plant (USFWS, pers. comm. 2003, p. 4). S. spaldingii remains green when 

much of the surrounding vegetation is brown during late summer and so may be 

preferentially selected by livestock. This impact may be reduced at some sites 

because during late summer livestock often remain close to water sources, which 

are usually not near areas where S. spaldingii resides (B. Benner, in litt. 2003, p. 

5). Trampling by livestock may also threaten the nests of ground dwelling 

pollinators (Sugden 1985, p. 309; Kearns and Inouye 1997, pp. 298-299) of S. 

spaldingii, including the bumblebee Bombus fervidus (Lesica 1993, p. 199; Lesica 

and Heidel 1996, p. 9;). The development of springs or ponds for additional 

livestock water sources may inadvertently increase adverse livestock grazing and 

trampling impacts on some S. spaldingii populations by allowing cattle to forage 

in areas they were previously unable to utilize. Routine livestock management 

such as salt placement and fence construction may also change grazing and 

trampling pressures at some sites. 

Aside from direct consumption or trampling impacts to Silene spaldingii, 

of concern is the habitat degradation and alterations to the ecosystem associated 

with livestock disturbances (summarized by Milchunas and Lauenroth 1993 and 

Jones 2000). In a worldwide review of 276 data sets to assess community 

sensitivity to grazing, Milchunas and Lauenroth (1993) found that corresponding 

 

6

 The caudex is the root crown, the persistent and often woody base of an otherwise herbaceous 

perennial plant. 
Recovery Plan for Silene spaldingii ● September 2007 

41 

changes in species composition were primarily a function of low above ground 

net primary production (arid communities) and little evolutionary history of 

grazing at a site. Using similar techniques Jones (2000) analyzed 54 studies and 

16 variables to assess grazing on North American arid ecosystems (across 

elevations, from forest ecosystems to grasslands, and across different grazing 

systems) and found 11 of the 16 variables revealed significant detrimental effects 

from cattle grazing. To name a few, the adverse effects from livestock can 

include changes in the timing and availability of pollinator food plants (Kearns 

and Inouye 1997, pp. 298-299), changes to insect communities (Kearns and 

Inouye 1997, pp. 298-299; Debano 2006), changes in water infiltration due to soil 

compaction (Jones 2000, Table 1), disturbance to soil microbiotic crusts (Belnap 

et al. 1999, p. 167; Jones 2000, Table 1), subsequent weed invasions (Parker et al.

2006), soil erosion from hoof action (Jones 2000, Table 1) and others. 

Unlike the east side of the Rockies where grasslands coevolved with 

bison, grasslands and steppe communities west of the Rockies historically 

experienced little pressure from large, hoofed animals during the last 10,000 years 

(the Holocene period) (Mack and Thompson 1982, Lyman and Wolverton 2002, 

Martin and Szuter 2002) and so are impacted more severely by adverse livestock 

grazing and trampling (Milchunas and Lauenroth 1993). Both Pseudoroegneria 

spicata (bluebunch wheatgrass) and Festuca idahoensis (Idaho fescue) are poorly 

adapted to herbivory by comparison with other grass species, having little 

compensatory growth such as tiller production (Caldwell et al. 1981, p. 14). This 

evolutionary phenomenon, its mechanisms, and its ecological implications has 

been the subject of considerable discussion (Burkhardt 1996; Lyman and 

Wolverton 2002; Martin and Szuter 2002; Moore 2002; Williams 2005; Adler et 

al. 2006). Disturbances, most frequently linked to adverse livestock grazing and 

trampling, have dramatically altered Western arid ecosystems in a progression 

from native perennial bunchgrass communities to invasive nonnative annual 

grasslands that are then susceptible to more invasive perennial plant invasions 

(DiTomaso 2000, p. 257). For example, the initial introduction and spread of the 

most prevalent invasive nonnative annual grass, Bromus tectorum (cheatgrass), 

throughout the range of Silene spaldingii is attributed to the grain industry as well 

as adverse grazing and trampling by livestock that occurred at the end of the 19th

century and early 20th century (Mack 1981, p. 10) (see the section “Invasive 

Nonnative Plants” above for a better discussion on the effects of B. tectorum). 
Recovery Plan for Silene spaldingii ● September 2007 

42 

Preliminary monitoring numbers from Washington suggest that properly 

managed livestock grazing may be compatible with the conservation of Silene 

spaldingii (USBLM, in litt. 2006, p. 5, Tables 1 and 2). However, this monitoring 

was not designed as a paired experiment with grazed vs. ungrazed treatments, nor 

does it monitor the vegetative community. Additional research is needed relating 

to herbivore impacts from both domestic and wild ungulates as well as more 

intensive monitoring at populations that are being grazed. It has been suggested 

that livestock grazing could be used at some sites where grasses produce large 

amounts of litter and fire is not practical as a management option; in such cases 

moderate grazing could create safe sites for germination and seedling 

establishment (P. Lesica, in litt. 2006, p. 3). 

6. Herbicide and Insecticide Spraying (Factor E) 

Herbicide and insecticide spraying is thought to be a problem for Silene 

spaldingii both within contiguous wild lands as well as more fragmented 

landscapes. Herbicide use has escalated in recent years as landowners and 

managers have realized that a large scale conversion to invasive nonnative plant 

populations is occurring, and have in turn resorted to more aggressive control 

measures. Herbicide spraying for invasive nonnative plants is occurring across 

the range of S. spaldingii via aerial (airplane or helicopter) spraying, boom 

spraying off a vehicle, and hand application on large tracts of wild lands as well 

as on more developed areas. On Federal lands and some State, Tribal, and private 

lands, surveys for S. spaldingii are occurring prior to spraying and if the plant is 

found actions are adjusted accordingly (see “Invasive Nonnative Plant Control 

Efforts” below). Other lands, particularly State, private, and highway right-ofways, are sprayed with herbicides and pesticides without first surveying for S. 

spaldingii. Landowners may or may not be aware that S. spaldingii occurs within 

their ownership. 

Accidental herbicide spraying is also a possibility. One site at Cave Gulch 

on Craig Mountain, Idaho, was aerially sprayed in 1997; Silene spaldingii was 

later found near this site and may have been affected by this spraying (K. Gray, in 

litt. 2004, p. 4). Another listed Canyon Grassland plant species, Mirabilis 

macfarlanei (Macfarlane’s four-o’clock), was accidentally aerially sprayed in 

1997 (C. Johnson, USBLM, in litt. 1997, p. 3). Herbicide spraying effects on S. 

spaldingii have not been researched, although it is reasonable to assume that 
Recovery Plan for Silene spaldingii ● September 2007 

43 

broad spectrum herbicides such as glyphosate, picloram, and 2,4-D that kill most 

herbaceous perennials will also kill S. spaldingii. Furthermore, invasive 

nonnative plant control activities, if not conducted carefully, can impact other 

native species and so result in habitat degradation (Lass et al. 1999, p. 3). 

Smaller populations of Silene spaldingii that exist within small pieces of 

remnant habitat are often found along roads, in between fields, or in cemeteries. 

These small pieces of habitat are susceptible to direct herbicide application, such 

as those occurring along roadsides to control invasive nonnative plants. They are 

also susceptible to herbicide drift, which occurs when herbicides are sprayed 

nearby and float through the air impacting adjacent areas. Herbicide drift is 

especially a problem on windy days or with aerial applications where there is 

more opportunity for drift to occur. Herbicide or pesticide drift threatens 

populations in Idaho (Lichthardt 1997, p. 12; J. Hill, in litt. 1999, p. 2), Oregon (J. 

Hustafa, U.S. Forest Service, pers. comm. 1999, p. 1; J. Kagan, ONHP, pers. 

comm. 1998, p. 1), and Washington (WNHP 2007, Element Occurrences 7, 8, 10, 

11, 18, 45, 51). For example, at least two S. spaldingii sites in Idaho are 

particularly vulnerable to herbicide drift because of their close proximity to 

cropland (Lichthardt 1997, p. 12). The sticky hairs blanketing the surface of S. 

spaldingii may help to protect the plant from some herbicide drift, as observed in 

other hairy plant species (Miller and Westra 2004, p. 3). 

Grasshopper and other insect control programs generally utilize broad 

spectrum insecticides that will affect native bee species (Johansen et al. 1983, p. 

1517). The effects of insect control programs on the pollinators of S. spaldingii

are unknown at this time. Because the species requires pollinators to reproduce, 

deleterious effects to the primary pollinators of S. spaldingii will translate into 

decreased reproductive output (Tepedino 1996, pp. III.5-2 to III.5-4; Lesica and 

Heidel 1996, p. 9). 

7. Adverse Grazing (Herbivory) and Trampling by Wildlife Species 

(Factor C) 

 Adverse grazing or browsing of Silene spaldingii inflorescences by native 

herbivores and livestock has been observed and is considered a threat to the 

species (Kagan 1989, p. 7; Heidel 1995, p. 4; B. Benner, in litt. 1999, p. 4; Hill 

and Weddell 2003, pp. 8-9; Hill and Gray 2004a, pp. 75-78; 2004b, pp. 15-19). 
Recovery Plan for Silene spaldingii ● September 2007 

44 

While grazing or browsing of S. spaldingii by native herbivores has occurred 

historically, problems may arise when numbers of native ungulates (deer and elk) 

are at levels significantly higher than those to which the plant has adapted. Longterm demography monitoring transects at Garden Creek Ranch, Craig Mountain, 

Idaho, found 50 percent of S. spaldingii reproductive stems were grazed in 2002 

and 70 percent in 2003 in areas where livestock were absent, therefore native 

ungulates were likely responsible (Hill and Weddell 2003, p. 9; Hill and Gray 

2004b, p. 17). At the Kramer Prairie site in Washington, heavy grazing has 

occurred where livestock is excluded; deer are thought to be the cause 

(Wentworth 1996, p. 5). 

 Rodent activity is also considered a significant factor affecting the 

persistence of S. spaldingii at several sites in eastern Washington and Idaho (B. 

Benner, in litt. 1999, p. 4; Caplow 2001, p. 5; Hill and Gray 2004b, pp. 15-19; P. 

Lesica, in litt. 2006, p. 3). For example, numerous S. spaldingii plants were 

marked with stakes and metal tags as part of a monitoring study on land managed 

by the Bureau of Land Management in Washington. On a site visit, the Bureau of 

Land Management botanist discovered that many of these plants were either 

broken off or missing completely and likely consumed by rodents, as evidenced 

by rodent burrowing activity in the area (B. Benner, in litt. 1999, p. 3). A 

monitoring plot at the Lamona site in Washington had intense adverse grazing in 

2005 that was attributed to rabbits or pocket gophers (P. Lesica, in litt. 2006, p. 3; 

2007b, p. 2). A Canyon Grassland demography study showed high mortality of S. 

spaldingii plants caused primarily by voles that appeared to prefer the plant, 

eating not only aboveground parts but also the caudex, which likely killed the 

plants. Rodents often tunneled under the plants and pulled several S. spaldingii 

stems down their holes (Hill 2006, p. 26). 

8. Off-Road Vehicle Use (Factors A, E) 

Off-road vehicle impacts are known to occur at two Silene spaldingii 

populations, one in Idaho and one in Washington (ICDC 2007, Element 

Occurrence 3; WNHP 2007, Element Occurrence 51). At the site in Idaho, offroad vehicle use is thought to be the primary threat to S. spaldingii (ICDC 2007, 

Element Occurrence 3). Because the habitat where S. spaldingii occurs is made 

up of flat or rolling hills, the plant is susceptible to off-highway vehicle use at 
Recovery Plan for Silene spaldingii ● September 2007 

45 

many sites rangewide. Off-highway vehicles may damage the caudex of S. 

spaldingii, likely killing the plant. 

9. Insect Damage and Disease (Factor C) 

Insect predation of foliage, flowers, and fruits of Silene spaldingii has 

been documented on numerous occasions (Heidel 1979, p. 69; Lesica 1988b, pp. 

2-5; Kagan 1989, p. 7; Youtie 1990, p. 4; Gamon 1991, p. 28; Lichthardt 1997, p. 

13; B. Benner, in litt. 1999, pp. 3-4; S. Riley, U.S. Forest Service, pers. comm. 

1999, p. 1; Hill and Gray 2000, p. 12; 2004b, p. 16; Hill and Weddell 2003, p. 8; 

R. Taylor, The Nature Conservancy of Oregon, in litt. 2003, p. 5; P. Lesica, in litt. 

2004, pp. 3-4). Predation on seed capsules has been documented to be as high as 

90 percent at the Kramer Prairie, Washington, site (Heidel 1979, p. 69), although 

lower percentages are more common. Most insect predation seems to be from 

larva (Hill and Gray 2000, p. 7; P. Lesica, in litt. 2004, pp. 3-4), although a seed 

weevil (Kagan 1989, p. 7; Youtie 1990, p. 4), and some other beetles (Heidel 

1979, p. 69) have also been implicated. Silene spaldingii has coevolved with 

insect predation, and so some level of predation is part of the ecosystem balance. 

However, small population sizes and a decrease in genetic diversity, or the 

presence of invasive nonnative plants, may exacerbate problems with insect 

predation. 

A fungal rust has been found on Silene spaldingii plants in Washington 

(B. Benner, in litt. 2004, p. 26). It is unknown how this rust may be affecting the 

species or how often it occurs. 

10. Impacts from Prolonged Drought and Climate Change (Factor E) 

Silene spaldingii has adapted to drought, evident in its prolonged 

dormancy response. Prolonged dormancy in S. spaldingii has been shown to 

increase reproduction (Lesica and Crone in review, p. 10) and could increase the 

likelihood of adult survival, therefore lessening the effect of drought. Perennial 

plants that are adapted to arid environments, such as S. spaldingii, are negatively 

impacted by prolonged and severe droughts (Schultz and Ostler 1995, p. 233). 

Prolonged periods of drought may increase the numbers of dormant individuals at 

a S. spaldingii site (Heidel 1995, p. 3; Lesica 1997, p. 356; B. Benner, in litt.

1999, p. 3; Lesica and Crone in review, p. 13), limiting the number of individuals 
Recovery Plan for Silene spaldingii ● September 2007 

46 

reproducing, which could make small populations more susceptible to extinction. 

A demography study in Idaho found that fewer plants were present at the later 

sampling period during drier years but earlier monitoring did not find a noticeable 

difference in individuals between years (J. Hill, in litt. 2007b, pp. 9-10). Based on 

demographic studies of mapped individuals of S. spaldingii, Lesica (1997, p. 349) 

considered plants that failed to reappear after 3 consecutive years to be dead. 

However, some S. spaldingii bouts of prolonged dormancy have lasted up to 6 

years (Lesica and Crone in review, pp. 9-10). 

Causes aside, global temperatures are increasing (USEPA, in litt. 2000, p. 

1). The effects of this climate change are speculative, but it has the potential to 

affect rare plants such as Silene spaldingii. Researchers speculate that this 

warming will alter rainfall patterns, with some regions becoming drier and others 

wetter (Given 1994, pp. 33-34). Within the Pacific Northwest a recent model 

predicts warmer and wetter winters in 80 years (U.S. Department of Energy 2004, 

p. 1). Plants are stationary, moving through dispersal, colonization, and 

recruitment events. Because plants are stationary and move slowly through the 

aforementioned events, it is thought they can’t move quick enough to keep up 

with a shifting climate, and are more susceptible to global warming than are 

wildlife species (Wilson 1989, p. 114). Furthermore, fragmentation and isolation 

limits movement opportunities. 

11. Inadequacy of Existing Regulatory Mechanisms (Factor D) 

Silene spaldingii, because of its threatened status, is protected on Federal 

lands where it occurs. Of the four states and one Canadian province where S. 

spaldingii resides, legal protection is provided only by the State of Oregon, where 

the species is listed as endangered by the Oregon Department of Agriculture 

(Oregon Department of Agriculture 2004, p. 11). Plants listed as threatened or 

endangered in Oregon are protected only on State lands; however, no S. spaldingii 

plants are currently found on State lands in Oregon. Although not granted any 

legal protection, S. spaldingii is on the State of Washington’s threatened species 

list and the red list in British Columbia. Silene spaldingii is not legally protected 

on any State or private lands. 

Special Federal land designations such as Areas of Critical Environmental 

Concern, Research Natural Areas, and Botanical Special Interest Areas have not 
Recovery Plan for Silene spaldingii ● September 2007 

47 

been designated within Silene spaldingii habitat except at Coal Creek, 

Washington, where an Area of Critical Environmental Concern has been 

established. 

The status assigned by State Natural Heritage Programs and Conservation 

Data Centers do not convey regulatory protection. However, their ranking system 

can help raise awareness for rare species. All four states and British Columbia 

rank the species as a G2 (imperiled globally because of rarity or because other 

factors demonstrably make it very vulnerable to extinction) S1 (critically 

imperiled in the applicable states or province because of rarity or some factor of 

its biology makes it especially vulnerable to extinction), except Washington 

where the State rank is S2, similar to the global (G) rank. 

H. CONSERVATION EFFORTS

1. Inventory Efforts 

Inventories for Silene spaldingii are being conducted on all lands managed 

by the Federal government where the plant currently resides or where there is 

suitable habitat. Surveys for the species should be done to complete consultation 

under section 7 of the Endangered Species Act for projects such as invasive 

nonnative plant control activities, right-of-ways, power lines, Federal highway 

projects, military activities, prescribed burns, and land acquisitions. In general, 

grazing allotments on federally managed lands have not been inventoried, 

although grazing lease renewals are being surveyed in Washington (B. Benner, in 

litt. 2004, p. 28) and in Oregon (G. Yates, U.S. Forest Service, in litt. 2004, p. 1). 

The Endangered Species Act does not require inventories for plants on State or 

private lands unless there is a Federal nexus. 

(a) Idaho. Within Idaho, extensive inventories have been conducted in the 

Craig Mountain Canyon Grasslands at Garden Creek Ranch by The Nature 

Conservancy, by the Bureau of Land Management both through annual surveys 

(Hill et al. 2001, p. 1) as well as during the course of a master’s thesis project 

(Menke 2003, p. 15), and in the Canyon Grasslands of Idaho by the Idaho 

Conservation Data Center (Hill et al. 2006, Figure 2). The Idaho Conservation 

Data Center has also done some inventory work on the Craig Mountain Wildlife 

Management Area owned by the Idaho Department of Fish and Game. However, 
Recovery Plan for Silene spaldingii ● September 2007 

48 

the majority of the known sites of S. spaldingii on Craig Mountain are located on 

Federal or Nature Conservancy lands. State owned lands are spread within and 

around these known sites and have generally not been inventoried. Surveys 

within the Craig Mountain area on State lands (Idaho Department of Fish and 

Game lands) are being planned in the near future. Surveys within grazing 

allotments and prescribed burning projects are ongoing on the Nez Perce National 

Forest and have led to several recently discovered populations (M. Hays, U.S. 

Forest Service, in litt. 2007, p. 1). Surveys on Nez Perce Tribal lands were 

initiated in 2005. No new populations were documented by this effort but work 

will continue in 2006 on Palouse Grassland remnants and in Canyon Grassland 

habitats (R. Miles, Nez Perce Tribal Executive Committee, in litt. 2006, p. 3). 

Palouse Grasslands have generally been surveyed only in association with section 

7 consultation projects, although increased attention to Palouse Grassland 

fragments is leading to an increase in non-project specific inventory efforts. 

(b) Montana. In Montana, the Montana Natural Heritage Program 

conducted a status report that was completed in 2005; this report included visits to 

all existing populations and searching some suitable habitat (Mincemoyer 2005). 

In 2003, Silene spaldingii was discovered at the Lost Trail National Wildlife 

Refuge outside of areas delineated as suitable habitat in Figure 4. This discovery 

indicates that other isolated grasslands in Montana may be capable of supporting 

S. spaldingii and should be further inventoried. The Plum Creek Timber 

Company, already working on conservation efforts for fish species, is a large 

landowner in the northwestern portion of Montana. Plum Creek Timber 

Company grasslands have not yet been searched for S. spaldingii (A. Wick, 

USFWS, in litt. 2004, p. 1). Surveys were conducted on Tribal lands within 

Montana in association with a status report (Mincemoyer 2005, pp. 13-14, 18, 24-

25). All suitable habitat on the Flathead National Forest was intensely surveyed 

for S. spaldingii in 2000 (M. Mantas, The Nature Conservancy of Montana, in litt.

2007, p. 2). 

(c) Oregon. In Oregon, The Nature Conservancy is in the process of 

inventorying its recently acquired Zumwalt Prairie Preserve and their Clear Lake 

Ridge Preserve lands have been inventoried (R. Taylor, in litt. 2003, p. 3). The 

Wallowa-Whitman National Forest has begun surveying active grazing allotments 

including areas within the Imnaha River Canyon and the lower Joseph Creek area 

(G. Yates, in litt. 2004, p. 2). Inventories on Nez Perce Tribal Land were initiated 
Recovery Plan for Silene spaldingii ● September 2007 

49 

in 2005 and will continue in 2006. No new populations were reported after the 

2005 effort (R. Miles, in litt. 2006, p. 3). 

(d) Washington. In Washington, inventories are being conducted on 

lands owned by the Bureau of Land Management (B. Benner, in litt. 2003, p. 6; C. 

Button, USBLM, in litt. 2004, p. 1), at the Fairchild Air Force Base (Caplow 

2001, p. 2), and at Turnbull National Wildlife Refuge (Weddell 2002, p. 3). 

Swanson Lake Wildlife Area, managed by the Washington Department of Fish 

and Wildlife, has been partially inventoried and Wawawai Canyon near the Snake 

River, managed by the Washington State Department of Natural Resources, has 

been inventoried (Caplow 2002b, p. 1). Inventories for Silene spaldingii have 

been done at the Lime Hill Area of Critical Environmental Concern and in Joseph 

Canyon, in Asotin County, Washington (C. Button, in litt. 2005, p. 1). 

Inventories on Nez Perce Tribal Land were initiated in 2005 and will continue in 

2006. No new populations were reported after the 2005 effort (R. Miles, in litt.

2006, p. 3). 

Many areas still remain to be inventoried where suitable habitat for Silene 

spaldingii exists. Because the Canyon Grasslands are extremely steep and quite 

remote, there are still significant portions of suitable habitat to be searched, 

particularly on the Oregon side of the Snake River directly across from Craig 

Mountain, along the lower Grande Ronde River in Oregon and Washington, the 

Imnaha River in Oregon, and the lower Clearwater and Salmon Rivers in Idaho 

(please see Hill and Gray 2004a, pp. 17-21 for a summary of areas to be 

surveyed). Over 40 percent of known S. spaldingii sites are on private land; in 

general, these private lands have had much less inventory effort. The possibility 

for large populations residing on private property can not be overlooked. Several 

recent Bureau of Land Management land acquisitions in Washington (B. Benner, 

in litt. 2003, p. 3), as well as The Nature Conservancy’s acquisition in 2000 of the 

Zumwalt Prairie Preserve, have led to the discovery of large, previously unknown 

S. spaldingii populations. 

2. Monitoring Efforts and Demographic Studies 

(a) Idaho. Two long-term demographic studies have been tracking 

permanent plots from 2002 to 2006 on Craig Mountain in the Canyon Grasslands: 

1) A cost-share project conducted at Garden Creek Ranch and funded by the 
Recovery Plan for Silene spaldingii ● September 2007 

50 

Bureau of Land Management’s Cottonwood Field Office in Idaho, the Idaho 

Conservation Data Center, and the Palouse-Clearwater Environmental Institute 

with seven permanent belt transects (four at a burned site and three at an unburned 

site) (Hill and Weddell 2003, p. 2; Hill and Gray 2004b, p. 1; Hill and Gray 

2005a, p. 2; Hill 2006, p. 2; J. Hill, in litt. 2007b, p. 10); and 2) a U.S. Fish and 

Wildlife Service and Idaho Conservation Data Center project with 10 permanent 

10 by 10 meter (33 by 33 foot) plots (4 on Bureau of Land Management’s 

Cottonwood Field Office lands at Garden Creek Ranch, 4 on State and 1 on 

Bureau of Land Management’s Cottonwood Field Office lands on Craig 

Mountain, and one on Bureau of Land Management’s Cottonwood Field Office 

lands along the lower Salmon River (Lichthardt and Gray 2002, p. 7; 2003, p. 5; 

Gray and Lichthardt 2004, p. 6; Hill and Gray 2005a, pp. 5-6; Gray and Hill 2006, 

pp 5-7). 

Trend monitoring where all aboveground stemmed plants were censused 

at both a 0.8-hectare (2-acre) and a 1.6 hectare (4–acre) site at the Garden Creek 

Ranch funded by The Nature Conservancy and the Idaho Bureau of Land 

Management occurred from 1999 to 2002 (Hill and Gray 2000, p. 4; Hill et al.

2001, p. 4; Hill and Fuchs 2002, pp. 3-4; 2003, p. 3). This study also includes 

three permanent belt transects that monitor invasive nonnative plants (two 

Centaurea solstitialis sites and one Poa pratensis site), and accurate mapping of 

seven S. spaldingii locales and invasive nonnative plants at these sites (Hill and 

Gray 2000, pp. 1-4; Hill et al. 2001, pp. 1, 3-4). Plots were established and 

monitored in 2001 and 2002 at Garden Creek Ranch in conjunction with a 

Master’s thesis to monitor invasive nonnative plant invasions and fire effects 

(Menke 2003, pp. 15-17, 44-46). One permanent monitoring transect was 

established in 1998 by the Idaho Bureau of Land Management (U.S. Bureau of 

Land Management 1998, p. 2). 

(b) Montana. In Montana, monitoring occurred at Wild Horse Island 

from 1986 to 1992 (P. Lesica, in litt. 2003, p.2). A demography study has been 

ongoing at The Nature Conservancy’s Dancing Prairie Preserve since 1987 

(Lesica 1988c, pp. 1-2; 1997, p. 349; 2005, p. 1; P. Lesica, in litt. 2003, p. 2; 

Lesica and Crone 2007, p. 1; Lesica and Crone in review, p. 5) and at the Lost 

Trail National Wildlife Refuge since 2003 (P. Lesica, in litt. 2003, p. 3; Lesica 

and Crone 2007, pp. 2). Trend monitoring has been conducted at The Nature 

Conservancy’s Dancing Prairie Preserve since 1991 (Lesica 2005, p. 2). 
Recovery Plan for Silene spaldingii ● September 2007 

51 

(c) Oregon. In Oregon, monitoring plots were established at Clear Lake 

Ridge in 1990, but were not revisited until 2002 (Youtie 1990, pp. 1-5; Elseroad 

and Taylor 2002, p. 3). The Wallowa-Whitman Forest has funding to design a set 

of monitoring methodologies on their land as well as Nature Conservancy lands in 

Oregon (J. Hustafa, in litt. 2004a, p. 1). Three permanent monitoring plots have 

been established on The Nature Conservancy’s Zumwalt Prairie Preserve to 

collect baseline abundance data and examine the effects of burning and grazing 

treatments (Taylor et al. 2006, pp. 1-4). In addition, phenology of S. spaldingii 

was tracked during 2006 on the Zumwalt Prairie Preserve (Dingeldein et al. 2006, 

p. 1). 

(d) Washington. In Washington, monitoring of individual plants has 

occurred at 10 sites in Lincoln County since 1995 in conjunction with habitat 

monitoring on lands where livestock grazing occurs (B. Benner, in litt. 1999, p. 3; 

2003, p. 6; USBLM, in litt. 2006, Table 1). Plots have been monitored at 

Fairchild Air Force Base since 1995 (F. Caplow, WNHP, in litt. 2003, p. 5). 

Demography transects were established at Lamona and in the Blue Mountains in 

2003 and have been monitored yearly since (Lesica and Crone 2007, pp. 3-4). 

3. Additional Sources of Scientific Information on Silene spaldingii 

• Preliminary pollination biology for Silene spaldingii in Montana (Lesica 

1988b, p. 1) 

• Germination requirements and seedling biology of Silene spaldingii

(Lesica 1988a, pp. 1-2; 1993, pp. 196, 198-200; A. Raven, pers. comm.

2004, p. 1) 

• Importance of pollinators for reproduction in Silene spaldingii in Montana 

(Lesica 1991, pp. 4-11; 1993, pp. 196-200) 

• The effect of fire on Silene spaldingii in Montana (Lesica 1991, 1994, 

1995, 1999) 

• Preliminary genetic investigation of Silene spaldingii done at five 

locations, one in Idaho, one in Montana, one in Oregon, and two in 

Washington (Baldwin and Brunsfeld 1995) 

• Pollination biology of Silene spaldingii at one site in Idaho, one in 

Montana, one in Oregon, and two in Washington (Lesica and Heidel 1996) 
Recovery Plan for Silene spaldingii ● September 2007 

52 

• An investigation of the utility of remote sensing techniques for mapping 

Centaurea solstitialis infestations in Idaho (Hill 2002a; 2002b) 

• Effects of invasive nonnative plants and fires on Silene spaldingii at 

Garden Creek Ranch, Idaho (Hill and Gray 2000, pp. 8-10, 13-16; Hill et 

al. 2001, pp. 6-7, 10-11; Hill and Fuchs 2002, pp. 3-5; 2003, pp. 3, 6-7, 9-

12; Lichthardt and Gray 2002, p. 6; Menke 2003; Gray and Lichthardt 

2004, pp. 16-19) 

4. Invasive Nonnative Plant Control Efforts 

At the Craig Mountain Wildlife Management Area in Idaho spraying for 

Centaurea solstitialis (yellow starthistle) with 2,4-D and Tordon has occurred 

during the last 10 years, with approximately 20 to 220 hectares (50 to 550 acres) 

being treated each year. Centaurea solstitialis biocontrol agents have been 

released and monitored for the last 10 years. Approximately 4 hectares (10 acres) 

of Onopordum acanthium (Scotch thistle) have been treated for the last 15 years. 

Other invasive nonnative plants being treated include Crupina vulgaris (common 

crupina) and Linaria (toadflax). These spraying activities are expected to 

continue into the future. Known populations of Silene spaldingii are not sprayed; 

however, until 2004, surveys for S. spaldingii were not conducted prior to 

spraying (J. White, pers.comm. 2003, p. 1). 

Cooperative Weed Management Areas and County Weed Boards that 

work to control invasive nonnative plants have been established across much of 

Silene spaldingii’s range. For example, the Tri-State Weed Management Area, 

established by the Bureau of Land Management in 1996, encompasses 101,170 

hectares (250,000 acres) on the Idaho, Oregon, and Washington borders. The 

intent of this Cooperative Weed Management Area is to bring together Federal, 

State, County, Tribal, and private organizations to control invasive nonnative 

plants, primarily Centaurea solstitialis, and educate the public about the threat 

invasive nonnative plants pose. The Tri-State Weed Management Area treated 

over 1,010 hectares (2,500 acres) of invasive nonnative plants in 2003, surveyed 

over 5,670 hectares (14,000 acres), and informed over 950 individuals about the 

dangers invasive nonnative plants pose (L. Danly, USBLM, in litt. 2004). 

The Nature Conservancy’s Dancing Prairie Preserve in Montana has been 

the site of a research project looking at the effects of herbicides and fire on 
Recovery Plan for Silene spaldingii ● September 2007 

53 

control of Potentilla recta (sulfur cinquefoil) (Lesica and Martin 2003). Annual 

and sometimes biannual spot-spraying from a backpack or ATV (all-terrain 

vehicle) of Potentilla recta, Hypericum perforatum (St. Johnswort), Hieracium 

pratense (meadow hawkweed), and Centaurea maculosa (spotted knapweed) has 

occurred for the last 9 years (P. Lesica, in litt. 2003, p. 3). Biocontrol agents were 

released on Hypericum perforatum in the late 1990s. Invasive nonnative plant 

control efforts are expected to continue into the future (M. Mantas, in litt. 2007, p. 

2). A 2-year Integrated Pest Management Plan was prepared for the Dancing 

Prairie Preserve in 2006 and will be revisited after the next inventory in 2008 (M. 

Mantas, in litt. 2007, p. 2). Control of Potentilla recta is occurring adjacent to 

Silene spaldingii populations at The Nature Conservancy’s Zumwalt Preserve in 

Oregon (R. Taylor, in litt. 2004, p. 1). 

Invasive nonnative plant control is an ongoing activity on most Federal 

lands. Because Silene spaldingii is a threatened species under the Endangered 

Species Act, Federal agencies are required to consider S. spaldingii in developing 

guidelines for all invasive nonnative plant control activities within the plant’s 

range. The Bureau of Land Management in Spokane first surveys suitable habitat 

and does not treat invasive nonnative plants near S. spaldingii (USBLM 2002a, 

pp. 5-8). The Bureau of Land Management’s Vale District in Oregon limits aerial 

herbicide treatment of invasive nonnative plants to distances greater than 152 

meters (500 feet), broadcast spraying would be done no closer than 8 meters (25 

feet), directed hand spraying no closer than 3 meters (10 feet), and by wicking 

applications only, if necessary, if within 3 meters (10 feet) of S. spaldingii 

(USFWS, in litt. 2002, pp. 7-13). The Bureau of Land Management’s 

Cottonwood Field Office in Idaho has all plants flagged within 30 meters (100 

feet) of S. spaldingii and stipulates no boom spraying within 15 meters (50 feet) 

of S. spaldingii, hand spraying/wick/wipe applications only at a distance from 1.5 

to 15 meters (5 to 50 feet), wipe or wick spraying from 1 to 1.5 meters (3 to 5 

feet), and manual control only within 1 meter (3 feet). Picloram may not be used 

within 15 meters (50 feet) of S. spaldingii (USFWS, in litt. 2003, pp. 5-7). 

Invasive nonnative plant control and management specific to Silene 

spaldingii has occurred at Craig Mountain, Idaho, on Bureau of Land 

Management land. General mapping of invasive nonnative plants at all S. 

spaldingii locales, specific mapping of Centaurea solstitialis patches at seven of 

these locales, and manual control of Centaurea solstitialis and planting of native 
Recovery Plan for Silene spaldingii ● September 2007 

54 

seed in disturbed areas at two of these locales has been done for 4 years at Garden 

Creek Ranch (Hill and Gray 2000, pp. 1, 4; Hill et al. 2001, pp. 1, 3-4; Hill and 

Fuchs 2002, pp. 2-3; 2003, pp. 1-2). The Bureau of Land Management’s 

Cottonwood Field Office in Idaho has released biocontrol insects for Centaurea 

solstitialis at S. spaldingii sites on Craig Mountain (Danly 1999). 

Other control measures have included the release of biological invasive 

nonnative plant control agents for Cirsium arvense (Canada thistle), Centaurea 

disffusa (diffuse knapweed), and Centaurea maculosa (spotted knapweed) in 1996 

at Fairchild Air Force Base in Washington (Rush and Gamon 1999, p. 7; Caplow 

2001, p. 9). A limited amount of invasive nonnative plant control has also 

occurred at the Chief Joseph Gravesite monument near Joseph, Oregon and an 

Integrated Pest Management plan has been established for the site (T. Nitz, U.S. 

National Park Service, pers. comm. 2004, p. 1). 

Annual grasses exist near S. spaldingii sites at Crow Creek on the 

Wallowa-Whitman National Forest in Oregon where grazing practices are being 

altered to improve range condition. One Centaurea solstitialis patch, located on 

private land, is within 0.8 kilometer (0.5 mile) of one S. spaldingii site at Crow 

Creek and has been treated for 5 years by U.S. Forest Service personnel (J. 

Hustafa, pers. comm. 1999, p. 1). Centaurea maculosa is being treated along the 

road to the above S. spaldingii site (J. Hustafa, in litt. 2004b, p. 2). 

The Joseph Creek population managed by the Nez Perce Tribe does not 

have significant noxious weed issues. The bunchgrass community is nearly 

pristine with very limited amounts of Bromus tectorum (cheatgrass) present. A 

small Crupina vulgaris population exists within 0.4 kilometer (0.25 mile) of the 

site and will continue to be hand pulled by tribal staff. No domestic livestock 

grazing is currently allowed at this site (R. Miles, in litt. 2006, p. 3). 
Recovery Plan for Silene spaldingii ● September 2007 

55 

5. Additional Conservation Actions 

• Silene spaldingii seeds have been collected at 1 population in Idaho 

(Garden Creek), 1 population in Montana (Wild Horse Island), 3 

populations in Oregon (Clear Lake Ridge, Crow Creek, and Joseph 

Creek), and 1 population in Washington (Coal Creek) in the following 

quantities: 400 seeds were collected in Oregon in 1989, 2,500 seeds in 

Oregon in 1990, almost 3,000 seeds from Montana in 1990, almost 2,000 

seeds from Oregon in 1995, 2,300 seeds from Idaho in 1999, 3,400 seeds 

from Washington in 2000, 2,200 seeds from Idaho in 2000, over 31,000 

seeds from Oregon in 2001, and 1,048 seeds from Oregon in 2005 (R. 

Miles, in litt. 2006, p. 3). All seeds are stored at the Berry Botanic Garden 

in Portland, Oregon (A. Raven, in litt. 2004). 

• A draft management plan has been developed for Garden Creek Ranch, 

Idaho, where Silene spaldingii locations have been identified and 

protection methodologies have been outlined (Hill 1998). 

• A management plan for Silene spaldingii has been developed for Fairchild 

Air Force Base in Washington (Rush and Gamon 1999). 

• A management plan has been developed for BLM lands along Coal Creek 

in Washington, emphasizing protection of Silene spaldingii and the state 

threatened plant Polemonium pectinatum (USBLM 2002b). 

• A land acquisition through the Land and Water Conservation Fund and 

other land exchanges are ongoing for Bureau of Land Management land 

within Silene spaldingii habitat in Washington (B. Benner, in litt. 2003, p. 

6) (see Section H-1, “Inventory Efforts”). 

• A Conservation Easement at Pocket Creek Ranch is being funded using 

U.S. Fish and Wildlife Service Recovery Land Acquisition Grant money. 

The (2,354-hectare) (5,817-acre) conservation easement is adjacent to The 

Nature Conservancy’s Zumwalt Prairie Preserve. 

• A prescribed burning plan has been developed at The Nature 

Conservancy’s Dancing Prairie Preserve in Montana that recommends 

burning similar size patches every other year. In 2003 39 hectares (97 

acres), in 2005 54 hectares (134 acres), and in 2007 82 hectares (203 

acres) of Silene spaldingii habitat were burned (M. Mantas, in litt 2007, p. 

2). 
Recovery Plan for Silene spaldingii ● September 2007 

56 

• Montana Fish, Wildlife, and Parks has tried for several years to burn the 

grasslands on Wildhorse Island but residents have opposed these efforts 

(P. Lesica, in litt. 2006, p. 3). 

• A management plan is being developed for The Nature Conservancy’s 

Zumwalt Preserve that will include conservation strategies for Silene 

spaldingii (R. Taylor, in litt. 2003, p. 6). 

• An amendment to the Nez Perce Precious Lands Wildlife Management 

Plan is under development to incorporate conservation measures for the 

Joseph Creek population (R. Miles, in litt. 2006, p. 4). 

• An ordination study of Silene spaldingii habitat at Garden Creek Ranch is 

underway (J. Hill, in litt. 2007b, p. 11). 

I. BIOLOGICAL CONSTRAINTS

The long-lived nature of Silene spaldingii, in conjunction with sporadic 

and rare recruitment, delayed maturity, cryptic rosettes that may disappear before 

monitoring, prolonged dormancy, and difficulties identifying seedlings, make it 

challenging to measure changes in numbers of individuals of this species. For 

plants exhibiting prolonged dormancy, population trend monitoring needs to 

occur for 3 or more consecutive years every 5 to 20 years to adequately assess 

trends at a given site (Lesica and Steele 1994; see details in Section II-A, 

Recovery Strategy and Rationale). Although population trend and demographic 

monitoring is occurring at a number of sites, long-term monitoring of this kind 

has occurred at only one S. spaldingii site, the Dancing Prairie Preserve in 

Montana (see section H, Conservation Efforts). Monitoring efforts to date have 

not used consistent methodologies so comparisons of key life history parameters 

across the range of the species are difficult. 

Ground disturbing activities including fires, adverse livestock grazing and 

trampling, and off-road vehicle use impact Silene spaldingii the most during the 

flowering and seeding period (late July to September) and during seedling and 

shoot emergence in early spring. 

Small, isolated populations relegated to remnant fragments of native 

habitat pose a problem as their viability into the future is questionable. Silene 

spaldingii requires grasslands dominated by native vegetation, with adequate 

numbers of pollinators available and other S. spaldingii populations close enough 
Recovery Plan for Silene spaldingii ● September 2007 

57 

(within 1.6 kilometers [1 mile]) to provide for pollen exchange and enhance gene 

flow and genetic variability. 
Recovery Plan for Silene spaldingii ● September 2007 

58 

II. Recovery Strategy and Goals 

A. RECOVERY STRATEGY AND RATIONALE

The fragmentation of much of Silene spaldingii’s habitat by human related 

activities has reduced the species to a mosaic of small populations (67 percent of 

the known remaining populations are composed of fewer than 100 individuals) 

occurring in isolated habitat remnants. Many of these small populations may not 

be viable into the future. Populations with few individuals and low effective 

population size are likely to suffer from low genetic diversity (Loveless and 

Hamrick 1984, p. 72, Table 1; Karron et al. 1988, p. 1118; Ellstrand 1992, pp. 77; 

Ellstrand and Elam 1993, pp. 219, 221, 226-227). As population size diminishes, 

the chance of loss of genetic diversity increases and the likelihood that gene flow 

from distant populations will replenish genetic variability decreases (Loveless and 

Hamrick 1984, pp. 72-73, Table 1). The fragmented distribution of small 

populations further contribute to the positive feedback loop that Gilpin and Soulé 

(1986, pp. 25-26) have termed an “extinction vortex.” These depleted 

populations, and the species that they constitute, are more susceptible to both 

predictable and unexpected genetic, environmental, and demographic vagaries 

(Shaffer 1987, pp. 73-75; Simberloff 1988, p. 499-501; Ellstrand 1992, p. 79; 

Ellstrand and Elam 1993, pp. 222, 228-229, 232). 

Because small, fragmented populations with limited gene flow and 

susceptibility to inbreeding face a greater risk of extinction (Frankham 2003, p. 

S22-S29), increasing the size and connectivity of the larger remaining Silene 

spaldingii populations will be an important component of the recovery strategy 

for the species. Preserving representative populations from across the range of S. 

spaldingii, throughout all of the physiographic regions in which it occurs, is also a 

key element of the recovery strategy. Reciprocal transplant studies have shown 

that there is often a high degree of local adaptive differentiation in plant 

populations (Ellstrand and Elam 1993, pp. 233-234 and references therein). 

Frankham (2003, p. S22-S29) points to a substantial need for the effective genetic 

management of fragmented populations of threatened species, but also notes that 

only rarely does such management take place. The preservation of genetic 

diversity across populations is important not only to short-term persistence (e.g., 

Huenneke 1991, p. 36; Newman and Pilson 1997, p. 360; Neel and Cummings 

2003, pp. 227-228 ), but also provides the material for future adaptation and 
Recovery Plan for Silene spaldingii ● September 2007 

59 

evolutionary potential, thereby increasing the species’ probability of persistence 

over the long-term (Lande and Barrowclough 1987, p. 87; Shaffer 1987, pp. 74-75 

and references therein; Simberloff 1988, p. 495; Nunney and Campbell 1993, p. 

238; Neel and Cummings 2003, p. 228). 

As to how many populations are necessary, if specific genetic data on the 

populations selected for conservation are lacking, a recent evaluation 

demonstrated that anywhere from 53 to 100 percent of the remaining populations 

must be preserved to meet the genetic diversity conservation standard of the 

Center for Plant Conservation (Neel and Cummings 2003, p. 228). In the absence 

of data, it is extremely difficult to determine the number of populations needed for 

long-term persistence. Especially when populations have become isolated as the 

result of relatively recent habitat fragmentation events, Hanski et al. (1996, p. 

535) noted that even the number of extant populations may not necessarily be 

sufficient, as it is possible these populations have not yet reached a steady state 

equilibrium. Given these considerations and based on the recommendations of 

species experts, in this plan we propose the preservation of a minimum of 3 key 

conservation areas per physiographic region, and higher numbers where it is 

believed that suitable habitat either does or potentially exists, to reach the total 

number of 27 key conservation areas across the historical range of Silene 

spaldingii intended to preserve the available genetic variability within the species 

and provide for its long-term persistence. It is preferable that these key 

conservation areas be spread across each physiographic region. 

 Estimating minimum population sizes needed to ensure long-term viability 

is also a challenge. Population viability analyses utilize computer modeling to 

estimate a population’s viability into the future under various threats and 

management scenarios. A population viability analysis that incorporates threats 

such as fire management, genetic data, and pollinator success, as well as 

demographic data (transition probabilities), has not been done for Silene 

spaldingii rangewide and is needed to identify those populations that should be 

the focus of conservation efforts and which management scenarios will best 

preserve these populations (Menges 2000, pp. 51-56; Oostermeijer et al. 2003, pp. 

389-398). Detailed information on parameters such as recruitment, growth, 

mortality, and age structure of the population are required to model population 

persistence (Menges 1990, p. 54; Schemske et al. 1994, pp. 590-591; Lesica 1997, 

p. 347; Menges 2000, p. 55), consequently many years of monitoring will be 
Recovery Plan for Silene spaldingii ● September 2007 

60 

needed to acquire the data necessary to conduct a population viability analysis for 

S. spaldingii. Without a population viability analysis, minimum viable population 

numbers for plants must be estimated utilizing data from the general literature and 

comparisons with similar species. 

 Minimum viable population size is most frequently and broadly estimated 

at 250 to 500 reproductive individuals (summarized in Schonewald-Cox et al. 

1983, p. 392). However, caution is needed when applying a standard minimum 

viable population number, especially to plants, since different life strategies may 

make them more or less susceptible to extinction (Menges 1991b, p. 49). For 

example, in one study, researchers determined that populations with fewer than 

100 breeding individuals are highly vulnerable to extinction through mutations, 

although this extinction may take 100 generations (Lynch et al. 1995, p. 509). 

Another study found plants that were primarily outcrossing species were more 

prone to extinction than other selfing species (Lennartsson 2002, p. 3069). 

Depending on factors such as population growth rates and the degree of 

environmental variation, some estimates of minimum viable populations range 

into the thousands or tens of thousands (Soulé and Simberloff 1986, p. 30; Shaffer 

1987, pp. 73-75; Nunney and Campbell 1993, p. 235; Lande 1995, pp. 784-789). 

Researchers examining Silene regia found that population size was not the 

primary influencing factor, but that fire management most significantly affected 

survivability into the future (Menges and Dolan 1998, pp. 74-75). A population 

viability analysis has not been done for S. spaldingii but would help to direct 

management, identify what factors are important for conservation of S. spaldingii, 

and which S. spaldingii populations are most important for conservation. In 

contrast to this utility of population viability analyses, establishing minimum 

viable population sizes can be difficult and problematic. For example, a recent 

review study predicting minimum viable population sizes for 1198 species found 

estimates were unrelated to the anthropogenic threats and were unrelated to 

extinction risk (Brook et al. 2006, p. 375). We suggest utilizing the standard 

minimum of at least 500 reproductive individuals. This number may be revisited 

with input from species experts upon the completion of a population viability 

analysis. More importantly, populations identified as key conservation areas will 

need to demonstrate stable or increasing trends. Sites with more than 500 plants 

will be maintained at or above current population numbers. 
Recovery Plan for Silene spaldingii ● September 2007 

61 

 This recovery plan emphasizes conservation efforts for larger populations 

of Silene spaldingii while attempting to preserve the genetic diversity within each 

of the five physiographic regions where the plant resides. This is in line with the 

conservation strategy suggested by Nunney and Campbell (1993, p. 237-238), 

which focuses on the preservation of several populations, each supporting a 

density of at least the minimum viable population size, across heterogeneous 

habitats. Until additional information on the population viability of S. spaldingii is 

available, all existing habitat supporting S. spaldingii should be protected and 

managed. In particular, emphasis should be placed on populations or areas that 

have the potential of supporting at least 500 individuals. We have defined such 

populations or areas as key conservation areas. A key conservation area 

possesses the following qualities: 

• Composed of intact habitat (not fragmented), preferably 40 acres (16 

hectares) in size or greater7

• Native plants comprise at least 80 percent of the canopy cover of the 

vegetation community 

• Adjacent habitat sufficient to support pollinating insects 

• Habitat is of the quality and quantity necessary to support at least 500 

reproducing individuals of Silene spaldingii 

The protection and management of these key conservation areas, or areas 

that have the potential to serve as key conservation areas, forms the foundation of 

the recovery strategy for Silene spaldingii. When possible, these key 

conservation areas should be surrounded by 300 acres of habitat that is intact or 

can be restored to eventually support S. spaldingii. Details regarding the 

identified key conservation areas for S. spaldingii are provided in the Recovery 

Actions Narrative (Section III-B), and the key conservation areas for each 

physiographic region are identified in Figures 6 through 10 of that section. 

The wide range of Silene spaldingii creates a suite of various habitats 

where a complex list of threats to the species interacts. This recovery plan seeks 

to address these threats and makes recommendations to ensure the persistence of 

the species. As described in detail in the Threats Assessment (Section I-G of this 

plan), the threats addressed include invasive nonnative plants, small populations 

and habitat fragmentation, livestock use, wildlife herbivory, fire suppression and 

 

7

 In some regions, such as the already severely fragmented Palouse prairie, reaching a minimum 

size of 40 acres (16 hectares) of contiguous habitat may not be feasible. 
Recovery Plan for Silene spaldingii ● September 2007 

62 

increases, habitat loss, and off-road vehicle use. The aim of the recovery strategy 

for S. spaldingii is to first manage its habitat on an ecosystem basis ⎯

maintaining the habitat so that S. spaldingii and its natural interactions within the 

ecosystem (e.g. pollinators, fire) may be maintained. This will be accomplished 

by developing and implementing habitat management plans at all key 

conservation areas that provide guidance in managing S. spaldingii, and that also 

address the threats to the species. To accomplish conservation and recovery of S. 

spaldingii a series of actions need to be implemented. Invasive nonnative plants 

need to be controlled and managed within S. spaldingii habitat with minimal 

impact to the species itself. Larger populations where small population size and 

fragmentation are less of a problem should be a higher priority for protection than 

smaller, more fragmented populations. In addition, in order to preserve the full 

array of genetic variability within the species, large populations are needed in 

each of the five geographic regions where the plant resides. Because successful 

recruitment events are sporadic and may be separated by several years, ex situ 

propagation and restoration to supplement existing populations will probably be 

necessary in order to meet the recovery goals. Fire management and prescribed 

burning need to be conducted carefully, with sound monitoring strategies and 

guided by the best available scientific information. Conservation actions should 

be implemented for those sites that occur on lands targeted for development. Offroad vehicle use within S. spaldingii populations should be prevented. Wildlife 

should be managed at levels that are compatible with S. spaldingii conservation, 

and livestock grazing and trampling should be managed so that S. spaldingii and 

its habitat are not adversely affected. 

Because Silene spaldingii has a long life span, takes several years to reach 

reproductive maturity, exhibits prolonged dormancy, and has sporadic recruitment 

events, long-term monitoring data are necessary to adequately assess trends 

within populations. Lesica and Steele (1994, p. 211) assessed the implications of 

prolonged dormancy in plants for monitoring, and point out that long-term 

monitoring is necessary to distinguish real population trends from the variation 

that may be observed over the short term due to recording error, prolonged 

dormancy, or other changes related to climatic fluctuations. They suggest that 

repeated sampling of permanent plots for 3 or more consecutive years (short-term 

sample) would be needed every 5 to 20 years (long-term period) to overcome the 

natural variability in population counts and make any statistically significant 

estimate of the population trend. Thus for a plant such as S. spaldingii, it will 
Recovery Plan for Silene spaldingii ● September 2007 

63 

take at least 3 years of repeated sampling to get a single data point from which to 

assess trends. Monitoring 3 out of every 5 years over a 20 year time period would 

yield a total of four data points for each permanent monitoring plot. We 

considered this to be the minimum amount of data required from which to 

estimate long-term population trends in S. spaldingii, leading to our 

recommendation that delisting be considered only after populations have been 

monitored for at least 20 years. 

Silene spaldingii should be closely monitored: 1) to determine population 

trends, reproductive success, and habitat conditions; and 2) to assess the effects of 

existing or potential threats on S. spaldingii and its important habitat. 

Effectiveness monitoring should also be developed to address management 

actions and ensure that the factors affecting S. spaldingii are being adequately 

addressed. Survey efforts are needed to identify other S. spaldingii populations 

that need conservation. Outreach will inform the public about the species so they 

may assist in conservation, and seed banks will help to protect the species from 

catastrophic losses. Funding is required to implement all of these actions. 

Finally, a regular review of this recovery plan is needed so that new information 

may be incorporated and management adjusted accordingly. 

B. RECOVERY GOALS, OBJECTIVES, AND CRITERIA

The goal of the recovery program is to recover Silene spaldingii to the 

point where it can be delisted, i.e., to remove the species from threatened status. 

The primary objectives to meet this goal are to reduce or eliminate the threats to 

the species, and protect and maintain multiple reproducing, self-sustaining 

populations distributed across each of the five distinct physiographic regions 

where it resides sufficient to ensure the 

long-term persistence of the species 

(Figures 4 and 5). 

Delisting of Silene spaldingii will 

be warranted when the species no longer 

meets the definition of threatened or 

endangered under the Endangered 

Species Act (Act) (Box 2). We set 

recovery criteria to serve as objective, 

Box 2. Definitions according to 

section 3 of the Endangered 

Species Act. 

Endangered Species 

Any species that is in danger of 

extinction throughout all or a significant 

portion of its range 

Threatened Species 

Any species that is likely to become 

endangered within the foreseeable 

future throughout all or a significant 

portion of its range 
Recovery Plan for Silene spaldingii ● September 2007 

64 

measurable guidelines to assist us in determining when a species has recovered to 

the point that the protections afforded by the Act are no longer necessary. 

However, the actual change in status is not solely dependent upon achieving the 

recovery criteria set forth in a recovery plan; it requires a formal rulemaking 

process based upon an analysis of the same five factors considered in the listing of 

a species (see pages 25 and 26). The recovery criteria presented in this recovery 

plan thus represent our best assessment of the conditions that would most likely 

result in a determination that delisting of S. spaldingii is warranted as the outcome 

of a formal five factor analysis in a subsequent regulatory rulemaking. The 

recovery criteria and actions outlined here reflect the information currently 

available on this species, and identify information needs that are pertinent to the 

long-term conservation and management of S. spaldingii. The rationales for the 

following criteria are contained below and within the following “Recovery Action 

Narrative.” 

Delisting Criteria 

Delisting of Silene spaldingii will be considered when all the following 

criteria are met: 

1. Twenty-seven populations, with at least 500 reproducing Silene spaldingii 

individuals in each and with intact habitat, occur rangewide at key 

conservation areas and are distributed throughout the 5 identified 

physiographic provinces as follows: 5 within the Blue Mountain Basins, 7 

within the Canyon Grasslands, 8 within the Channeled Scablands, 4 within 

the Intermontane Valleys, and 3 within the Palouse Grasslands. Given the 

uncertainty associated with creating new key conservation areas (i.e.

transplanting) and the limited available habitat within the Palouse 

physiographic region, the delisting criteria of three key conservation areas 

within the Palouse will be evaluated within 10 years (2017) based on new 

information. Populations with more than 500 plants will be maintained at 

or above current population numbers. 

The number of populations/key conservation areas for each physiographic 

province was set at a minimum of three to preserve genetic diversity. For 

some regions, a greater number of key conservation areas are proposed to 

reflect the number of populations needed to maintain connectivity and, to 
Recovery Plan for Silene spaldingii ● September 2007 

65 

the extent possible, preserve historical distribution across the remaining 

potential habitat estimated to be available (Factors A-E). 

2. All 27 key conservation areas of Silene spaldingii are composed of at least 

80 percent native vegetation (by canopy cover), have adjacent habitat 

sufficient to support pollinating insects, and are not fragmented (i.e., 

intact; see criterion #1) (Factor A). 

3. Populations of Silene spaldingii at key conservation areas demonstrate 

stable or increasing population trends (less than a 10 percent chance that 

the population is declining) for at least 20 years. To address this criterion, 

consistent range-wide long-term monitoring methodologies that identify 

what parameters will be monitored, how, and at what frequency need to be 

developed. Acceptable statistical power and false-change error rates will 

be established at a later date when a standardized rangewide monitoring 

protocol is developed (Factors A-E). 

4. Habitat management plans have been developed and implemented for all 

key conservation areas. These management plans will provide for the 

protection of Silene spaldingii habitat, and will also protect the ecosystem 

by addressing conservation of other rare species, reducing the identified 

threats (e.g., off-road vehicle use, adverse grazing and trampling by 

wildlife and domestic stock, herbicide application, etc.), protecting 

pollinators, enacting monitoring strategies, incorporating integrated pest 

management strategies, and incorporating appropriate fire management 

activities (Factors A, C, D). 

5. Invasive nonnative plants with the potential to displace Silene spaldingii

have been continually controlled or eradicated within 100 meters (328 

feet) of all S. spaldingii populations within key conservation areas (Factor 

A). Certain invasive plants that are established and difficult to eradicate, 

as detailed for each physiographic province under Recovery Actions 1.1.4, 

1.2.4, 1.3.4, 1.4.4, and 1.5.5, may be controlled within 25 meters (82 feet) 

of S. spaldingii populations. 

6. Prescribed burning is conducted, whenever possible, to mimic historical 

fire regimes within a particular physiographic region in Silene spaldingii 
Recovery Plan for Silene spaldingii ● September 2007 

66 

habitat. Prior to burning, presence/absence surveys for the plant will be 

completed. Prescribed burning of more than 30 percent of the individuals 

at a S. spaldingii population should not occur at any one time and should 

not take place when it may exacerbate invasive nonnative plant 

populations unless invasive nonnative plant control measures, monitoring, 

and a management strategy are in place prior to the prescribed burn. 

Where S. spaldingii is present, monitoring is enacted prior to and 

following the prescribed burn. Historical fire regimes are carefully 

analyzed utilizing the best available technology (Factors A, E). 

7. Seed banking occurs ex situ first at all smaller Silene spaldingii

populations (not key conservation areas or potential key conservation 

areas) and second at all larger S. spaldingii populations (key conservation 

areas or potential key conservation areas) to preserve the breadth of 

genetic material across the species’ range (Factor A). 

8. A post-delisting monitoring program for the species will be developed and 

ready for implementation. This program will be developed through 

coordination with the Bureau of Land Management, U.S. Forest Service, 

U.S. Fish and Wildlife Service, Tribes, States, The Nature Conservancy, 

and other interested parties (Factors A-E). 
Recovery Plan for Silene spaldingii ● September 2007 

67 

III. Recovery Program 

The recovery program presented here is separated into two parts: (1) 

recovery actions specific to each of the physiographic regions; and (2) general 

recovery actions. Because differences are considerable between physiographic 

regions, this split is needed to address recovery actions specific to a physiographic 

region while still identifying recovery actions that are applicable rangewide. 

A. STEPDOWN OUTLINE OF RECOVERY ACTIONS

1. Conserve, identify, develop, and expand Silene spaldingii populations and 

habitat in each of the five physiographic regions where S. spaldingii resides. 

1.1. Conserve, identify, and expand Silene spaldingii populations and habitat 

within the Blue Mountain Basins (goal: five key conservation areas). 

1.1.1. Conserve and work to enhance the four Silene spaldingii 

populations within the Blue Mountain Basins identified here as 

potential key conservation areas. 

1.1.2. Conduct further surveys to identify, or work to create, at least one 

new population and key conservation area within the Blue 

Mountain Basins with over 500 individuals. 

1.1.3. Conserve and protect smaller populations within the Blue 

Mountain Basins. 

1.1.4. Control and manage invasive nonnative plant species specific to 

the Blue Mountain Basins. 

1.2. Conserve, identify, and expand Silene spaldingii populations and habitat 

within the Canyon Grasslands (goal: seven key conservation areas). 

1.2.1. Conserve and work to enhance the five Silene spaldingii

populations within the Canyon Grasslands identified here as 

potential key conservation areas. 

1.2.2. Conduct further surveys to identify at least two new populations 

and potential key conservation areas within the Canyon Grasslands 

with over 500 individuals. 

1.2.3. Conserve and protect smaller populations within the Canyon 

Grasslands. 

1.2.4. Control and manage invasive nonnative plant species specific to 

the Canyon Grasslands. 
Recovery Plan for Silene spaldingii ● September 2007 

68 

1.3. Conserve, identify, and expand Silene spaldingii populations and habitat 

within the Channeled Scablands (goal: eight key conservation areas). 

1.3.1. Conserve, survey, and work to enhance the seven Silene spaldingii

populations within the Channeled Scablands identified here as 

potential key conservation areas. 

1.3.2. Conduct further surveys to identify, or work to create, at least one 

new population and key conservation area within the Channeled 

Scablands with over 500 individuals. 

1.3.3. Conserve and protect smaller populations within the Channeled 

Scablands. 

1.3.4. Control and manage invasive nonnative plant species specific to 

the Channeled Scablands. 

1.4. Conserve, identify, and expand Silene spaldingii populations and habitat 

within the Intermontane Valleys (goal: four key conservation areas). 

1.4.1. Conserve and work to enhance the three Silene spaldingii

populations within the Intermontane Valleys identified here as 

potential key conservation areas. 

1.4.2. Conduct further surveys or work to supplement existing 

populations within the Intermontane Valleys to achieve at least one 

additional potential key conservation areas with over 500 

individuals. 

1.4.3. Conserve and protect smaller populations within the Intermontane 

Valleys. 

1.4.4. Control and manage invasive nonnative plant species specific to 

the Intermontane Valleys. 

1.5. Conserve, identify, develop, and expand Silene spaldingii populations and 

habitat within the Palouse Grasslands (goal: three key conservation 

areas). 

1.5.1. Conserve and work to enhance the three Silene spaldingii

populations within the Palouse Grasslands identified here as a 

potential key conservation areas. 

1.5.2. Conduct a study identifying intact habitat within the Palouse 

Grasslands where Silene spaldingii may occur and follow with 

surveys for the plant. 

1.5.3. Supplement existing populations and conduct a restoration and 

reintroduction program within the Palouse Grasslands to achieve 
Recovery Plan for Silene spaldingii ● September 2007 

69 

the goal of three key conservation areas of Silene spaldingii with 

over 500 individuals. 

1.5.4. Conserve and protect smaller populations within the Palouse 

Grasslands. 

1.5.5. Control and manage invasive nonnative plant species specific to 

the Palouse Grasslands. 

2. Conduct general recovery actions across the range of Silene spaldingii. 

2.1. Revise and implement general management plans to include Silene 

spaldingii where the species resides. 

2.2. Develop Silene spaldingii specific habitat management plans at all key 

conservation areas. 

2.3. Habitat management plans and recovery actions should manage for 

impacts and threats to Silene spaldingii populations and habitat both at 

key conservation areas as well as at smaller populations.

2.3.1. Implement invasive nonnative plant control and integrated pest 

management programs at all Silene spaldingii sites, taking care not 

to impact S. spaldingii. 

2.3.1.1.Incorporate integrated pest management programs into habitat 

management plans for Silene spaldingii at all key conservation 

areas and other areas as needed. 

2.3.1.2.Conduct invasive nonnative plant control and management 

measures at all key conservation areas and other populations as 

needed. 

2.3.1.3.Ensure invasive nonnative plant control and management 

measures are coordinated with appropriate agencies. 

2.3.1.4.Conduct outreach activities for individuals or organizations 

that are involved in controlling and managing invasive 

nonnative plants. 

2.3.1.5.Conduct surveys for Silene spaldingii before invasive 

nonnative plant control measures are implemented. 

2.3.1.6.Develop and implement guidelines for herbicide applications 

around Silene spaldingii plants. 

2.3.1.6.1. Develop set distances where various herbicide 

application techniques may be used near Silene 

spaldingii plants. 

2.3.1.6.2. Develop set distances for specific herbicides that may 

be employed near known Silene spaldingii sites. 
Recovery Plan for Silene spaldingii ● September 2007 

70 

2.3.1.6.3. Develop guidelines for the timing of herbicide 

applications. 

2.3.2. Conduct fire management activities within Silene spaldingii

habitat. 

2.3.2.1. Incorporate fire management plans into habitat 

management plans for all Silene spaldingii populations 

identified as key conservation areas and other areas as 

needed. 

2.3.2.2. Carefully conduct prescribed burns within Silene 

spaldingii habitat. 

2.3.2.2.1. Conduct surveys for Silene spaldingii before 

prescribed burns are implemented. 

2.3.2.2.2. Monitor the effects to Silene spaldingii and 

its habitat from all burns. 

2.3.2.2.3. Do not conduct prescribed burns where 

invasive nonnative plant infestations exist 

unless accompanied by an integrated pest 

management program and monitoring. 

2.3.3. Protect Silene spaldingii sites from development on public and 

private lands. 

2.3.4. Monitor and manage livestock grazing and associated management 

activities to avoid impacts to Silene spaldingii and its habitat. 

2.3.4.1. Manage and mitigate livestock grazing and associated 

management activities to avoid and minimize impacts to 

Silene spaldingii and its habitat. 

2.3.4.2. Monitor livestock grazing and associated management 

activities to measure and manage impacts to Silene 

spaldingii and its habitat. 

2.3.5. Implement effective off-road vehicle use control measures. 

2.3.6. Monitor and manage wildlife populations and associated 

management activities to avoid impacts to Silene spaldingii and its 

habitat. 

2.3.7. Avoid herbicide use not related to controlling invasive nonnative 

plant infestations specific to protecting Silene spaldingii and all 

insecticide use within a 1.6 kilometer (1 mile) radius of all S. 

spaldingii populations. 

2.4. Monitor population trends and habitat conditions. 
Recovery Plan for Silene spaldingii ● September 2007 

71 

2.4.1. Monitor Silene spaldingii populations at key conservation areas 

periodically to determine population trends. 

2.4.2. Conduct demographic monitoring across the range of Silene 

spaldingii. 

2.4.3. Monitor and evaluate the response of Silene spaldingii to fire and 

invasive nonnative plants. 

2.4.4. Obtain permission from private landowners to conduct population 

trend monitoring for Silene spaldingii on private lands. 

2.4.5. Determine if sites with no plants have been extirpated. 

2.5. Conduct research essential to the conservation of Silene spaldingii.

2.5.1. Determine population viabilities for Silene spaldingii populations. 

2.5.2. Develop new populations or supplement existing populations of 

Silene spaldingii where appropriate. 

2.5.2.1. Utilize existing potential key conservation areas and 

identify new key conservation areas with good habitat 

where new populations should be developed or where 

existing populations could be supplemented. 

2.5.2.2. Determine the best techniques and develop guidelines for 

creating new populations or supplementing existing 

populations of Silene spaldingii. 

2.5.2.3. Develop guidelines to ensure genetic conservation during 

supplementation, re-introduction, and introduction 

activities. 

2.5.2.4. Determine the best techniques to restore Silene spaldingii 

habitat. 

2.5.3. Conduct research essential to controlling and managing invasive 

nonnative plants within Silene spaldingii habitat. 

2.5.4. Conduct research essential to managing livestock, wildlife, and 

insect herbivory at Silene spaldingii populations. 

2.5.5. Conduct research to better determine the effects of fire on Silene 

spaldingii and identify when and where prescribed fire should 

occur, particularly outside of Montana. 

2.5.6. Conduct further research regarding reproductive biology and 

essential pollinators for Silene spaldingii. 

2.5.7. Conduct research investigating seed dispersal mechanisms for 

Silene spaldingii. 
Recovery Plan for Silene spaldingii ● September 2007 

72 

2.5.8. Conduct research on soil seed bank ecology including seed 

longevity, seed viability, and genetics. 

2.5.9. Conduct further genetic research including genetic diversity and 

gene flow across Silene spaldingii’s range. 

2.6. Conduct surveys in potential habitat areas. Manage and protect any 

newly discovered Silene spaldingii populations. 

2.6.1. Conduct surveys on Federal lands for Silene spaldingii. 

2.6.2. Conduct surveys on State and Tribal lands, especially where 

activities may affect Silene spaldingii habitat. 

2.6.3. Obtain permission from private landowners to conduct surveys for 

Silene spaldingii on private lands. 

2.6.4. Protect newly discovered Silene spaldingii populations. 

2.7. Support conservation on privately owned lands. 

2.7.1. Support conservation actions on lands owned by The Nature 

Conservancy. 

2.7.2. Support conservation activities on other private lands. 

2.7.3. Conduct outreach and awareness efforts with the public regarding 

Silene spaldingii’s plight and its conservation. 

2.8. Pursue land and species designations that will help facilitate conservation 

of Silene spaldingii. 

2.9. Establish propagule banks, including a long-term seed storage facility for 

Silene spaldingii. 

2.10. Secure funding for implementation of recovery tasks. 

2.11. Validate and revise recovery objectives as needed. 

2.12. Convene annual meetings of the Silene spaldingii technical team. 

3. Develop a post-delisting monitoring plan. 

.
Recovery Plan for Silene spaldingii ● September 2007 

73 

B. RECOVERY ACTION NARRATIVE

1. Conserve, identify, develop, and expand Silene spaldingii populations and 

habitat in each of the five physiographic regions where S. spaldingii 

resides. In general, large populations have higher genetic diversity than 

smaller populations and so have a higher survivability (Barrett and Kohn 

1991, pp. 5-6). In addition, genes in wide ranging taxa also vary across the 

larger landscape (Huenneke 1991, pp. 32-33). To preserve the genetic 

integrity of Silene spaldingii, larger populations are prioritized before smaller 

populations, and representative populations from each of the five 

physiographic regions are identified. Until a population viability analysis has 

been done for S. spaldingii that models which populations are viable under 

various management strategies, a minimum of 500 reproducing individuals ⎯

assumed to represent the minimum viable population size ⎯ will be the 

default goal for all key conservation areas in each of the five physiographic 

regions (identified below and in Figures 6 through 10). Within regions, 

attempts should be made to develop key conservation areas so that they are 

distributed across each physiographic region. Several physiographic regions 

(the Blue Mountain Basins, Canyon Grasslands, and Channeled Scablands) 

will likely reach their key conservation area goals through further survey 

efforts, whereas the Intermontane Valleys and Palouse Grasslands may require 

the creation or supplementation of populations such that their key 

conservation area goals can be met. 

Box 3. Interpretation of Figures 6 thru 10, key conservation areas for Silene 

spaldingii in each of the five physiographic regions. 

 Buffers were computer generated using element occurrence record (or site) data. 

 If 0.8 kilometer (0.5 mile) buffers around element occurrence records (sites) 

overlapped, sites were grouped together into a single population. Overlap indicated 

two sites were within 1.6 kilometers (1 mile) of one another. 

 Physiographic regions as delineated in Figure 4 are repeated within these figures for 

the specific physiographic region pictured. 

 One-mile and 2-mile buffers have been included to indicate satellite populations with 

the potential to become part of adjacent populations, depending upon further surveys. 

 Population numbers and key conservation areas are identified in each figure only for 

the physiographic region delineated within the dashed line. 

 Potential key conservation areas are indicated with labeled boxes. 
Recovery Plan for Silene spaldingii ● September 2007 

74 

Figure 6. The 14 known Silene spaldingii populations and 4 potential key 

 conservation areas within the Blue Mountains physiographic region.
Recovery Plan for Silene spaldingii ● September 2007

75 

Figure 7. The 22 known Silene spaldingii populations and 5 potential key 

 conservation areas identified within the Canyon Grasslands 

 physiographic region.
Recovery Plan for Silene spaldingii ● September 2007 

76 

Figure 8. The 33 known Silene spaldingii populations and 7 potential key 

 conservation areas identified within the Channeled Scablands 

 physiographic region.
Recovery Plan for Silene spaldingii ● September 2007

77 

Figure 9. The 10 Silene spaldingii populations and 3 potential key conservation areas 

 identified within the Intermontane physiographic region.
Recovery Plan for Silene spaldingii ● September 2007 

78 

Figure 10. The 18 Silene spaldingii populations and 3 potential key conservation 

 areas within the Palouse Grasslands physiographic region.
Recovery Plan for Silene spaldingii ● September 2007 

79 

1.1. Conserve, identify, and expand Silene spaldingii populations and 

habitat within the Blue Mountain Basins (goal: five key conservation 

areas). The Blue Mountain Basins of Oregon, with 14 Silene spaldingii

populations, have 4 potential key conservation areas identified here: Clear 

Lake Ridge, Crow Creek, Wallowa Lake, and the Zumwalt Prairie (Figure 

6). The populations on The Nature Conservancy’s Zumwalt Prairie 

Preserve were not discovered until the land was purchased in 2000, and 

there appear to be substantial tracts of suitable habitat on unsurveyed 

private, Tribal, and public lands, so it is reasonable to assume there are 

most likely other populations of S. spaldingii within the Blue Mountain 

Basins. Therefore, the goal of 5 populations of S. spaldingii with both 

intact habitat and a minimum of 500 reproducing individuals within the 

Blue Mountain Basins is justified. Populations with fewer than 500 

individuals, not identified as potential key conservation areas, should be 

conserved where possible, particularly on federally managed land. 

1.1.1. Conserve and work to enhance the four Silene spaldingii 

populations within the Blue Mountain Basins identified here as 

potential key conservation areas. The population at Clear Lake 

Ridge (considered here as part of the Blue Mountain Basins and not 

the Canyon Grasslands) has at least 331 individuals, Crow Creek has 

at least 2,385 individuals, Wallowa Lake has at least 506 individuals, 

and the Zumwalt Prairie has at least 1,917 individuals. Furthermore, 

all four populations have other satellite populations nearby (generally 

within 5 kilometers [3 miles]) with intact habitat between; S. 

spaldingii could be found in these intervening spaces in the future. 

Three of the four potential key conservation areas already have more 

than 500 individuals; only Clear Lake Ridge has fewer. This 

population should be better surveyed to potentially locate more 

individuals. If no more individuals can be located, supplementing 

the population with individuals grown from local seed sources should 

be considered (see Recovery Action 2.5.2). The Clear Lake Ridge 

population is predominantly managed by The Nature Conservancy 

and the Wallowa-Whitman National Forest, although some sites are 

on private land. Crow Creek is predominantly managed by the 

Wallowa-Whitman National Forest, with a small site or portions of 
Recovery Plan for Silene spaldingii ● September 2007 

80 

sites on private land. The Wallowa Lake population is almost 

entirely privately owned with the exception of a site at the Chief 

Joseph Gravesite managed by the National Park Service. The 

Zumwalt Prairie is within the confines of The Nature Conservancy’s 

Zumwalt Prairie Preserve. The recent acquisition of an unsurveyed 

conservation easement on property adjacent to the Zumwalt Prairie 

Preserve may add additional S. spaldingii individuals in the future. 

The numerous landowners involved will provide an additional 

challenge in conserving the species within the Blue Mountain Basins. 

1.1.2. Conduct further surveys to identify, or work to create, at least 

two new populations and key conservation area within the Blue 

Mountain Basins with over 500 individuals. With additional 

survey work, particularly on private land, it is expected that 

additional populations of S. spaldingii will be located within the Blue 

Mountain Basins. If new populations are not identified, 

supplementing existing populations (see Recovery Action 2.5.2) 

should be considered to achieve the recovery goal of five key 

conservation areas in this region. 

1.1.3. Conserve and protect smaller populations within the Blue 

Mountain Basins. Several smaller populations exist within the Blue 

Mountain Basins. These populations should also be protected from 

threats (see recovery actions listed under 2). Those populations that 

occur on private lands may benefit from education and outreach 

activities (see actions 2.3.1.4 and 2.7.3), conservation easements and 

voluntary cooperation (see action 2.7).

1.1.4. Control and manage invasive nonnative plant species specific 

to the Blue Mountain Basins. Invasive nonnative plant species vary 

by physiographic region. Within the Blue Mountain Basins, invasive 

nonnative plant species of concern include: Centaurea maculosa

(spotted knapweed), C. diffusa (diffuse knapweed), C. solstitialis 

(yellow starthistle), Cirsium arvense (Canada thistle), Poa pratensis 

(Kentucky bluegrass), and Potentilla recta (sulfur cinquefoil). These 

invasive nonnative plant species, and others as they are discovered, 

should be controlled or eliminated utilizing integrated pest 
Recovery Plan for Silene spaldingii ● September 2007 

81 

management practices (Bottrell 1979; Luken and Thieret 1997) 

within 100 meters (328 foot) of Silene spaldingii populations (see 

Recovery Action 2.3.1). Other invasive nonnative grass species 

including Bromus tectorum (cheatgrass), and Ventenata dubia

(ventenata), should be controlled using integrated pest management 

practices to within 25 meters (82 feet) of Silene spaldingii 

populations. 

1.2. Conserve, identify, and expand Silene spaldingii populations and 

habitat within the Canyon Grasslands (goal: seven key conservation 

areas). The Canyon Grasslands of Idaho, Oregon, and Washington, with 

22 Silene spaldingii populations, have 5 potential key conservation areas 

identified here: the Blue Mountain Foothills, Center Ridge, Craig 

Mountain, Garden Creek, and Joseph Creek (Figure 7). The Joseph Creek 

site is included here despite its small population size (161 plants) because 

of the quality and extent of intact habitat, the potential to discover more 

sites in the immediate area, and because it occurs on the Nez Perce 

Precious Lands Wildlife Management Area which offers permanent 

protection (R. Miles, in litt. 2006, p. 4). The Canyon Grasslands are steep 

and therefore difficult to survey and there remain large tracts of 

unsurveyed intact habitat, so it is expected there may be many more 

populations of S. spaldingii within this physiographic region. Therefore, 

the goal of seven populations of S. spaldingii with intact habitat and a 

minimum of 500 reproducing individuals within the Canyon Grasslands is 

justifiable. Populations with fewer than 500 individuals, not identified as 

key conservation areas, should be conserved where possible, particularly 

on federally managed land.

1.2.1. Conserve and work to enhance the five Silene spaldingii 

populations within the Canyon Grasslands identified here as 

potential key conservation areas. Three of these populations 

already number more than 500 individuals: the Blue Mountain 

Foothills has at least 997, Center Ridge has an estimated 500 

individuals, and Garden Creek has at least 3,987 individuals. Two 

separate populations comprise the Craig Mountain key conservation 
Recovery Plan for Silene spaldingii ● September 2007 

82 

area as shown in Figure 7: Captain John Creek with at least 223 

individuals to the north, and Billy Creek with at least 220 individuals 

to the south. Much of the land between these two sites remains 

unsurveyed and it is expected that with further survey effort this may 

become one larger population. With still further surveys, it is 

possible that the Garden Greek and Craig Mountain key conservation 

areas may constitute one single large population. The Joseph Creek 

site contains at least 161 individuals with a high potential to discover 

more within one mile of the known site. There is extensive habitat in 

the immediate area with good opportunity to discover or create 

additional populations. The Blue Mountains Foothills population is 

managed by the Umatilla National Forest. The Center Ridge 

population is managed by the Nez Perce National Forest. Craig 

Mountain is managed by the Bureau of Land Management 

Cottonwood Field Office in the south and the Idaho Department of 

Fish and Game in the north. Garden Creek is managed by the Bureau 

of Land Management and The Nature Conservancy. The Nez Perce 

Tribe manages the Joseph Creek population with support from the 

Bonneville Power Administration (R. Miles, in litt. 2006, p. 5).

1.2.2. Conduct further surveys to identify at least two new potential 

key conservation areas within the Canyon Grasslands with over 

500 individuals. All of the populations within the Canyon 

Grasslands have been discovered within the last 15 years, and most 

within the last 10 years. Prior to the discovery of these populations, 

the Canyon Grasslands had not been searched for Silene spaldingii. 

The Canyon Grasslands are extremely steep and difficult to access, 

which has kept the habitat relatively intact and under surveyed. For 

these reasons, it is expected that there are many more populations of 

S. spaldingii within this physiographic region with intact habitat. In 

addition to the three potential key conservation areas already 

identified (Recovery Action 1.2.1), at least three additional potential 

key conservation areas must be established to meet the recovery goal 

for this region. If two new populations cannot be discovered with 

increased survey effort, the establishment of new populations should 

be considered (see Recovery Action 2.5.2).
Recovery Plan for Silene spaldingii ● September 2007 

83 

1.2.3. Conserve and protect smaller populations within the Canyon 

Grasslands. Several smaller populations exist within the Canyon 

Grasslands. These populations should also be protected from threats 

(see recovery actions listed under 2). Those populations that occur 

on private lands may benefit from education and outreach activities 

(see actions 2.3.1.4 and 2.7.3), conservation easements and voluntary 

cooperation (see action 2.7).

1.2.4. Control and manage invasive nonnative plant species specific 

to the Canyon Grasslands. Within the Canyon Grasslands, invasive 

nonnative plants of concern include: Acroptilon repens (Russian 

knapweed), Cardaria draba (whitetop), Centaurea diffusa (diffuse 

knapweed), Centaurea maculosa (spotted knapweed), Crupina 

vulgaris (common crupina), Euphorbia esula (leafy spurge), 

Lepidium latifolium (perennial pepperweed), Linaria dalmatica 

(Dalmatian toadflax), Onopordum acanthium (Scotch thistle), and 

Potentilla recta (sulfur cinquefoil). These invasive nonnative plants 

and others as they are discovered should be controlled or eliminated 

utilizing integrated pest management practices (Bottrell 1979; Luken 

and Thieret 1997) within a 100 meters (328 foot) of Silene spaldingii 

populations at key conservation areas (see Recovery Action 2.3.1). 

Other invasive nonnative plants including bur chervil (Anthriscus 

caucaluis), Bromus tectorum (cheatgrass), Centaurea solstitialis

(yellow starthistle), and Hypericum perforatum (St. Johnswort), Poa 

pratensis (Kentucky bluegrass), and Ventenata dubia (ventenata) are 

already relatively common within the Canyon Grasslands and so 

would be extremely expensive and difficult to control. Instead, these 

invasive nonnative plant species should be controlled using 

integrated pest management practices to within 25 meters (82 feet) of 

S. spaldingii populations. Where these more widespread invasive 

nonnative plants are not already present within S. spaldingii 

populations, such as Centaurea solstitialis at the Blue Mountain 

Foothills, control or eradication should occur within 100 meters (328 

feet).

1.3. Conserve, identify, and expand Silene spaldingii populations and 

habitat within the Channeled Scablands (goal: eight key conservation 
Recovery Plan for Silene spaldingii ● September 2007 

84 

areas). The Channeled Scablands region of Washington, with 35 Silene 

spaldingii populations, has 7 potential key conservation areas identified 

here: Coal Creek –Lamona, Crab Creek, Fishtrap Lake – Miller Ranch, 

Rocky Ford, Swanson Lake, Telford, and Twin Lakes (Figure 8). Intact 

habitat comprises many of these areas, which if fully surveyed have the 

potential to yield many more Silene spaldingii populations. In addition, 

many recent land acquisitions have led to the discovery of substantial new 

populations of S. spaldingii. Therefore, the goal of eight populations of S. 

spaldingii with intact habitat surrounding the populations and a minimum 

of 500 reproducing individuals is attainable within the Channeled 

Scablands. Populations with fewer than 500 individuals, not identified as 

potential key conservation areas, should be conserved where possible, 

particularly on federally managed land. 

1.3.1. Conserve, survey, and work to enhance the seven Silene 

spaldingii populations within the Channeled Scablands identified 

here as potential key conservation areas. Of these 7 potential key 

conservation areas, the Coal Creek – Lamona (500 individuals) and 

Telford (1100 individuals) populations currently have over 500 

individuals. To meet the recovery goal for this region, at least 5 of 

the remaining potential key conservation areas must be further 

surveyed or enhanced to achieve the minimum of 500 individuals. 

At present, Crab Creek has at least 162 individuals, Fishtrap Lake – 

Miller Ranch has at least 490 individuals in two populations, Rocky 

Ford has over 300 individuals, Swanson Lake has over 487 

individuals at one population and over 220 at another, and Twin 

Lakes has 603 individuals in four populations. Two of these 

potential key conservation areas, Fishtrap Lake – Miller Ranch and 

Swanson Lake, includes more than one population of Silene 

spaldingii. Both of these sites are within relatively intact habitat 

which if more thoroughly surveyed may lead to the discovery of 

more S. spaldingii individuals in interspaces. Crab Creek and Rocky 

Ford, with more extensive survey effort, could be part of the same 

population. The Coal Creek – Lamona, Crab Creek, Fishtrap Lake – 

Miller Ranch, Rocky Ford, and Telford key conservation areas are all 
Recovery Plan for Silene spaldingii ● September 2007 

85 

managed by the Bureau of Land Management Spokane District. 

Twin Lakes are managed by both the Bureau of Land Management 

Spokane District as well as private landowners. Swanson Lake is 

managed by the Bureau of Land Management Spokane District and 

the Washington Department of Fish and Wildlife. Preferably, at 

least one key conservation area would be located in the northeastern 

portion of the Channeled Scablands, closer to Spokane and one 

further south to get better geographical spacing of key conservation 

areas. 

1.3.2. Conduct further surveys to identify, or work to create, at least 

one new population and key conservation area within the 

Channeled Scablands with over 500 individuals. At least one 

additional population and key conservation area is needed within the 

Channeled Scablands. Populations towards the southern and 

northeastern reaches of the Channeled Scablands are small and 

isolated. To preserve genetic material across the Channeled 

Scablands, it would be better if new populations and key 

conservation areas were found or developed in these areas. 

1.3.3. Conserve and protect smaller populations within the 

Channeled Scablands. Numerous smaller populations exist within 

the Channeled Scablands. These populations should also be 

protected from threats (see recovery actions listed under 2). Those 

populations that occur on private lands may benefit from education 

and outreach activities (see actions 2.3.1.4 and 2.7.3), conservation 

easements and voluntary cooperation (see action 2.7) 

1.3.4. Control and manage invasive nonnative plant species specific 

to the Channeled Scablands. Within the Channeled Scablands, 

invasive nonnative plants of concern include: Cirsium arvense 

(Canada thistle), Centaurea diffusa (diffuse knapweed), Chondrilla 

juncea (rush skeletonweed), Euphorbia esula (leafy spurge), Linaria 

(toadflax), and Centaurea solstitialis (yellow starthistle). These 

invasive nonnative plants and others as they are discovered should be 

controlled or eliminated utilizing integrated pest management 

practices (Bottrell 1979; Luken and Thieret 1997) within 100 meters 
Recovery Plan for Silene spaldingii ● September 2007 

86 

(328 foot) of S. spaldingii populations at key conservation areas (see 

Recovery Action 2.3.1). Other invasive nonnative plants including 

Poa pratensis (Kentucky bluegrass), Bromus tectorum (cheatgrass), 

Ventenata dubia (ventenata), and Hypericum perforatum (St. 

Johnswort) are already relatively common within the Channeled 

Scablands and so would be extremely expensive to control. Instead, 

these invasive nonnative plant species should be controlled using 

integrated pest management practices to within 25 meters (82 feet). 

1.4. Conserve, identify, and expand Silene spaldingii populations and 

habitat within the Intermontane Valleys (goal: four key conservation 

areas). The Intermontane Valleys of Montana, with 11 Silene spaldingii 

populations, have three potential key conservation areas identified: 

Crosson Valley, Dancing Prairie, and Lost Trail (Figure 9). Two of these 

sites, Crosson Valley and Dancing Prairie, already have populations with 

over 500 individuals. Further surveys and supplementation of already 

existing populations may be necessary within the Intermontane Valleys to 

achieve the recovery goal of four populations with a minimum of 500 

individuals. Populations with fewer than 500 individuals, not identified 

within potential key conservation areas, should be conserved where 

possible, particularly on federally managed lands. 

1.4.1. Conserve and work to enhance the three Silene spaldingii 

populations within the Intermontane Valleys identified here as 

potential key conservation areas. The Dancing Prairie key 

conservation area has over 10,000 individuals and is the largest 

known population of Silene spaldingii. Crosson Valley (near 

Sullivan Hill) was recently resurveyed and 651 individuals were 

counted. Lost Trail is separated into 2 populations, one with 203 

individuals, and one with 177 individuals. The Crosson Valley key 

conservation area is on the Flathead Indian Reservation, home of the 

Confederated Salish and Kootenai Tribes. The Dancing Prairie key 

conservation area is composed of lands managed by The Nature 

Conservancy on its Dancing Prairie Preserve. Lost Trail is managed 

by the U.S. Fish and Wildlife Service and adjacent Montana State 

Trust Lands.
Recovery Plan for Silene spaldingii ● September 2007 

87 

1.4.2. Conduct further surveys or work to supplement existing 

populations within the Intermontane Valleys to achieve at least 

one additional key conservation areas with over 500 individuals. 

The Dancing Prairie and Crosson Valley sites already meet the 

criteria of 500 individuals for key conservation areas. Two 

additional key conservation areas with at least 500 individuals are 

needed to meet the recovery goal for this region. These additional 

key conservation areas may be established through either further 

survey effort or enhancement of known sites. Although not 

identified in Figure 9, a series of small, isolated valleys exist within 

Montana where suitable habitat and populations of Silene spaldingii 

may exist. If 2 new populations with a minimum of 500 individuals 

cannot be discovered with increased survey effort, the 

supplementation of existing potential key conservation area 

populations should be considered (see Recovery Action 2.5.2). Sites 

with known populations in intact habitat that could potentially be 

enhanced to function as key conservation areas include Wild Horse 

Island and the Cromwell Creek/Hog Heaven Range sites. It has been 

suggested that a key conservation area be established somewhere 

near Kalispell because one extirpated site was near this area (P. 

Lesica, in litt. 2006, p. 4). 

1.4.3. Conserve and protect smaller populations within the 

Intermontane Valleys. Several smaller populations exist within the 

Intermontane Valleys. These populations should also be protected 

from threats (see recovery actions listed under 2). Those populations 

that occur on private lands may benefit from education and outreach 

activities (see actions 2.3.1.4 and 2.7.3), conservation easements and 

voluntary cooperation (see action 2.7).

1.4.4. Control and manage invasive nonnative plant species specific 

to the Intermontane Valleys. Within the Intermontane Valleys, 

invasive nonnative plants of concern include: Hieracium pratense

(meadow hawkweed), Centaurea maculosa (spotted knapweed), and 

Potentilla recta (sulfur cinquefoil). These invasive nonnative plants 

and others as they are discovered should be controlled or eliminated 
Recovery Plan for Silene spaldingii ● September 2007 

88 

utilizing integrated pest management practices (Bottrell 1979; Luken 

and Thieret 1997) within 100 meters (328 foot) of Silene spaldingii 

populations at key conservation areas (see Recovery Action 2.3.1). 

Other invasive nonnative plants including Poa pratensis (Kentucky 

bluegrass), Bromus tectorum (cheatgrass), Cirsium arvense (Canada 

thistle), and Hypericum perforatum (St. Johnswort) are already 

relatively common within S. spaldingii Intermontane Valley sites and 

so would be extremely expensive to control. Instead, these invasive 

nonnative plant species should be controlled using integrated pest 

management to within 25 meters (82 feet) of S. spaldingii 

populations. 

1.5. Conserve, identify, develop, and expand Silene spaldingii populations 

and habitat within the Palouse Grasslands (goal: three key 

conservation areas). The Palouse Grasslands of Idaho and Washington, 

with 17 Silene spaldingii populations, have 3 potential key conservation 

areas identified: the Kramer Palouse Natural Area, Paradise 

Ridge/Gormsen Butte, and the Pitt Cemetery (Figure 10). Two of these 

sites, the Kramer Palouse Natural Area and the Pitt Cemetery are small 

(under 16 hectares [40 acres]) and have fewer than 500 individuals. 

Paradise Ridge/Gormsen Butte currently has no Silene spaldingii 

individuals, but is a larger site (over 150 acres [60 hectares]) that is 

protected through interested landowners as well as conservation easements 

but currently has no S. spaldingii. The Idaho Department of 

Transportation is considering a plan to attempt introducing S. spaldingii 

plants to another private land site in Idaho. Of the five physiographic 

regions, the Palouse Grasslands have been most heavily impacted by 

agricultural development with few large intact parcels of lands remaining. 

To better survey for potential S. spaldingii populations, the Palouse 

Grasslands need to be first surveyed for intact stands of habitat, and 

subsequently these should be searched for S. spaldingii. To preserve 

genetic material from this physiographic region, supplementing or 

developing new S. spaldingii populations that can be adequately conserved 

will be necessary to attain the goal of three populations with a minimum of 

500 reproducing individuals. Because it represents a larger area of 

contiguous Palouse Prairie habitat, Kamiak Butte in Washington has also 

been suggested as a potential key conservation areas, no S. spaldingii 
Recovery Plan for Silene spaldingii ● September 2007 

89 

plants currently reside there. Populations with fewer than 500 individuals, 

not currently identified as potential key conservation areas, should be 

conserved where possible, particularly on federally managed lands. 

1.5.1. Conserve and work to enhance the three Silene spaldingii 

populations within the Palouse Grasslands identified here as 

potential key conservation areas. The Kramer Palouse Natural 

Area has at least 200 Silene spaldingii individuals and is within two 

miles of another population with 11 individuals. The Pitt Cemetery 

has at least 62 S. spaldingii individuals. Paradise Ridge/Gormsen 

Butte currently has no Silene spaldingii but comprises over 150 acres 

960 hectares) of intact Palouse Prairie; the landowners manage the 

land and are willing to have S. spaldingii introduced there. The 

Kramer Palouse Natural Area is managed by Washington State 

University, the Pitt Cemetery is privately owned and Paradise Ridge 

is privately owned. Other key conservations areas are needed where 

existing or new populations of S. spaldingii can be supplemented or 

established within the Palouse Grasslands (see Recovery Action 

2.5.2). 

1.5.2. Conduct a study identifying intact habitat within the Palouse 

Grasslands where Silene spaldingii may occur and follow with 

surveys for the plant. With over 95 percent of the Palouse 

Grasslands lost to agricultural development, very few intact 

grasslands remain in this area. A study that identifies parcels of land 

that are over 4 hectares (10 acres) in size with potential Silene 

spaldingii habitat is needed. Subsequently, these parcels should be 

surveyed for the plant. 

1.5.3. Supplement existing populations and conduct a restoration and 

reintroduction program within the Palouse Grasslands to achieve 

the goal of three key conservation areas of Silene spaldingii with 

over 500 individuals. The recovery goal for this region may be met 

through a combination of enhancing the two extant populations 

identified as potential key conservation areas (Recovery Action 

1.5.1) and restoration and reintroduction to establish additional key 

conservation areas. If intact habitat exists or if adjacent habitat can 
Recovery Plan for Silene spaldingii ● September 2007 

90 

be restored, existing populations of Silene spaldingii within the 

Palouse Grasslands should be supplemented (see Recovery Action 

2.5.2) to create self sustaining populations of S. spaldingii with a 

minimum of 500 individuals. In the event that existing populations 

cannot be expanded, a new site with intact habitat that can be 

conserved should be identified and planted with nearby genetic 

material from S. spaldingii. If intact habitat cannot be found, 

restoration should occur at a site that can be conserved and 

subsequently planted with nearby genetic material from S. spaldingii. 

1.5.4. Conserve and protect smaller populations within the Palouse 

Grasslands. Numerous smaller populations exist within the Palouse 

Grasslands, most on private lands. These populations should also be 

protected from threats (see recovery actions listed under 2). Those 

populations that occur on private lands may benefit from education 

and outreach activities (see actions 2.3.1.4 and 2.7.3), conservation 

easements and voluntary cooperation (see action 2.7).

1.5.5. Control and manage invasive nonnative plant species specific 

to the Palouse Grasslands. Within the Palouse Grasslands, invasive 

nonnative plants of concern include: Chondrilla juncea (rush 

skeletonweed), Potentilla recta (sulfur cinquefoil), Dipsacus 

sylvestris (teasel), Linaria (toadflax), and Centaurea solstitialis 

(yellow starthistle). These invasive nonnative plants and others as 

they are discovered should be controlled or eliminated utilizing 

integrated pest management practices (Bottrell 1979; Luken and 

Thieret 1997) within 100 meters (328 foot) of Silene spaldingii 

populations at key conservation areas (see Recovery Action 2.3.1). 

Other invasive nonnative plants, including Anthriscus caucalis (bur 

chervil), Bromus tectorum (cheatgrass), Cirsium arvense (Canada 

thistle), Hypericum perforatum (St. Johnswort), and Poa pratensis

(Kentucky bluegrass), are already relatively common within S. 

spaldingii Palouse Grassland sites and so would be extremely 

expensive and difficult to control. Instead, these invasive nonnative 

plant species should be controlled using integrated pest management 

practices to within 25 meters (82 feet) of S. spaldingii populations. 
Recovery Plan for Silene spaldingii ● September 2007 

91 

2. Conduct general recovery actions across the range of Silene spaldingii. 

Many recovery actions are applicable across Silene spaldingii’s range. These 

actions are condensed here instead of being repeated for each physiographic 

region above. These actions should protect important (occupied and 

potentially suitable) habitat and implement actions that may be necessary to 

eliminate or control threats. Habitat should be managed to maintain or 

enhance viable populations of S. spaldingii, to protect pollinators, and to allow 

for the maintenance of natural ecosystem functions and processes and 

contribute to the long-term preservation of this species. 

2.1. Revise and implement general management plans to include Silene 

spaldingii where the species resides. Land management agencies 

including Federal, State, Tribal, and private entities that are responsible for 

the development and revision of land management plans should 

specifically address conservation of Silene spaldingii in their plans. 

Federal agencies include: the Bureau of Land Management (Spokane 

District in Washington, and the Coeur d’Alene and Cottonwood Field 

Offices in Idaho), the Department of Defense (Fairchild Air Force Base), 

the National Park Service (Chief Joseph Gravesite in Oregon), the U.S. 

Fish and Wildlife Service (Lost Trail National Wildlife Refuge in Montana 

and Turnbull National Wildlife Refuge in Washington), and the U.S. 

Forest Service (Wallowa-Whitman National Forest in Oregon, the Nez 

Perce and Clearwater National Forests in Idaho, and the Umatilla National 

Forest in Oregon and Washington). State managed lands include: the 

Craig Mountain Wildlife Management Area managed by the Idaho 

Department of Fish and Game; Montana State managed lands adjacent to 

the Lost Trail National Wildlife Refuge and on Wild Horse Island State 

Park; and in Washington on the Swanson Lakes Wildlife Area, at the 

Steptoe Butte State Historic Area, and at three sites managed by 

Washington State University, the Smoot Hill Reserve, the Kramer Palouse 

Natural Area, and the Washington State University Prairie Preserve. 

Tribal lands where the species resides includes lands owned by the 

Confederated Salish and Kootenai Tribes and the Nez Perce Tribe. Silene 

spaldingii is not currently included in any management plans for these 

areas. The Nature Conservancy manages three populations of S. spaldingii

at their Garden Creek Ranch Preserve in Idaho, the Dancing Prairie 

Preserve in Montana, and the Zumwalt Prairie Preserve in Oregon. If 
Recovery Plan for Silene spaldingii ● September 2007 

92 

management plans are developed for these sites, conservation of S. 

spaldingii should be incorporated. Actions specific to S. spaldingii 

identified within general land management plans should include 

recommendations made in S. spaldingii habitat management plans (see 

Recovery Action 2.2) and be consistent with the actions identified in this 

recovery plan. 

2.2. Develop Silene spaldingii habitat management plans at all key 

conservation areas. All key conservation areas identified in 1.1, 1.2, 1.3, 

1.4, and 1.5 above should have habitat management plans developed 

specifically to assist in conserving S. spaldingii at these sites. 

Management plans should include provisions to identify and control 

factors that may degrade habitat quality for S. spaldingii, such as 

nonnative plant invasions, changes in the fire regime, land conversions, 

adverse livestock grazing and trampling, herbicide or pesticide use, 

wildlife herbivory, off-road vehicle use, and insect damage and disease. 

When cross-agency coordination is needed for activities such as invasive 

nonnative plant control through integrated pest management programs, 

prescribed burns, or herbicide use, management plans should indicate who 

will take the lead and how that coordination will be accomplished. Plans 

should incorporate principles of adaptive management. 

2.3. Habitat management plans and recovery actions should manage for 

impacts and threats to Silene spaldingii populations and habitat both 

at key conservation areas as well as at smaller populations. Threats 

include invasive nonnative plants; problems associated with small, 

geographically isolated populations; changes in the fire regime and fire 

effects; land conversion associated with urban and agricultural 

development; adverse livestock grazing and trampling; herbicide and 

insecticide spraying; adverse grazing (herbivory) and trampling by wildlife 

species; off-road vehicle use; insect damage and disease; impacts from 

prolonged drought and climate change; and an inadequacy of existing 

regulatory mechanisms. All of these threats should be addressed both 

through habitat management plans and recovery actions both at key 

conservation areas as well as at smaller populations.
Recovery Plan for Silene spaldingii ● September 2007 

93 

2.3.1. Implement invasive nonnative plant control and integrated 

pest management programs at all Silene spaldingii sites, taking 

care not to impact S. spaldingii. Invasive nonnative plants may 

deleteriously affect Silene spaldingii through direct competition and 

habitat degradation. Therefore, ongoing invasive nonnative plant 

control and management is needed at all S. spaldingii sites. 

Unfortunately invasive nonnative plant control activities, such as 

herbicide applications, may also negatively affect S. spaldingii

individuals. While invasive nonnative plant control is necessary, it 

should be done with care to minimize effects from control activities 

on S. spaldingii. Integrated pest management strategies that utilize 

the least aggressive tool necessary to enact control measures when 

economic and/or ecological values are affected should be 

incorporated into S. spaldingii habitat management plans (Bottrell 

1979; Luken and Thieret 1997). 

2.3.1.1.Incorporate integrated pest management programs into 

habitat management plans for Silene spaldingii at all key 

conservation areas and other areas as needed. Effective 

control and management of invasive nonnative plant species 

cannot be done without considering impacts to Silene spaldingii

and, more importantly, its habitat. Without a healthy native 

plant community, habitat degradation is accelerated, thereby 

impacting the threatened species. Integrated pest management 

(Bottrell 1979; Luken and Thieret 1997) plans should seek to 

control nonnative plant invasions while maintaining or restoring 

the native plant community, not just S. spaldingii. Integrated 

pest management strategies utilize the least aggressive tool 

necessary to achieve management goals. Incorporating 

integrated pest management strategies into habitat management 

plans should facilitate the conservation of S. spaldingii as well 

as its habitat. Integrated pest management strategies are needed 

at all key conservation areas (see Recovery Actions 1.1, 1.2, 

1.3, 1.4, and 1.5 above), and should be targeted to maintain 

cover of native species at 80 percent or greater within each area. 

Integrated pest management strategies should identify all 

control methods available such as prevention, manual control, 
Recovery Plan for Silene spaldingii ● September 2007 

94 

biological control, and herbicide control. These integrated pest 

management strategies should include periodic weed surveys to 

detect new infestations or new invasive nonnative plant species, 

restore areas where weeds have been controlled to prevent 

reinvasion, and monitoring and evaluation to determine if 

control goals are being met. 

2.3.1.2.Conduct invasive nonnative plant control and management 

measures at all key conservation areas and other 

populations as needed. Physiographic region specific 

guidelines for invasive nonnative plant control and management 

measures are listed above (see Recovery Actions 1.1.3, 1.2.3, 

1.3.2, 1.4.3, and 1.5.4). Implementation of integrated pest 

management strategies should be conducted at all key 

conservation areas. 

2.3.1.3.Ensure invasive nonnative plant control and management 

measures are coordinated with appropriate agencies. 

Invasive nonnative plant control and management efforts should 

be coordinated with the U.S. Fish and Wildlife Service, U.S. 

Bureau of Land Management, U.S. National Forests, private 

landowners, County, Tribal, and State agencies to ensure the 

protection of S. spaldingii individuals and habitat. This will 

minimize the opportunity for S. spaldingii plants to be 

inadvertently harmed by invasive nonnative plant control 

activities. 

2.3.1.4.Conduct outreach activities for individuals or organizations 

that are involved in controlling and managing invasive 

nonnative plants. Many organizations that conduct invasive 

nonnative plant control measures on a regular basis may be 

accidentally spraying Silene spaldingii because of identification 

problems or because they do not realize the plant is an imperiled 

species (USFWS, pers. comm. 2004, p. 6). Outreach is needed 

to inform invasive nonnative plant management agencies such 

as Weed Management Areas, County Weed Boards, State and 

County highway maintenance programs, and programs for 
Recovery Plan for Silene spaldingii ● September 2007 

95 

herbicide applicators to prevent inadvertent spraying of S. 

spaldingii. Counties with S. spaldingii sites include Idaho, 

Lewis, and Nez Perce Counties in Idaho; Flathead, Lake, 

Lincoln, and Sanders Counties in Montana; Wallowa County in 

Oregon; and Adams, Asotin, Lincoln, Spokane, and Whitman 

Counties in Washington. 

2.3.1.5.Conduct surveys for Silene spaldingii before invasive 

nonnative plant control measures are implemented. Surveys 

should be conducted in all suitable habitats prior to spraying for 

invasive nonnative plants. If possible, surveys should not be 

conducted during drought years, since many Silene spaldingii

plants may remain dormant and consequently will not be 

visible. 

2.3.1.6.Develop and implement guidelines for herbicide 

applications around Silene spaldingii plants. Herbicides will 

deleteriously affect Silene spaldingii; therefore, careful 

application is needed to minimize effects to S. spaldingii. 

Chemicals and application methods will differ by site. A 

preliminary set of guidelines that can be altered to match 

specific sites is offered below to assist land managers and 

owners in determining how and where to apply various 

herbicides. Invasive nonnative plant control, when possible, 

should occur when S. spaldingii is dormant (October thru 

March), to minimize effects to the plant. When possible use 

herbicides that break down in the environment quickly, since 

chemicals that are longer lived in the environment such as 

picloram based chemicals are more likely to travel and affect 

non-target organisms (Cox 1998, p. 16 to 19). 

2.3.1.6.1. Develop set distances where various herbicide 

application techniques may be used near Silene 

spaldingii plants. Before spraying at Silene spaldingii 

sites, all individuals should be located and flagged. All 

herbicide applications should occur when wind speeds are 

less than 8 kilometers (5 miles) an hour to minimize 
Recovery Plan for Silene spaldingii ● September 2007 

96 

herbicide drift. Aerial spraying (from airplanes or 

helicopters) should not occur within 305 meters (1,000 

feet) of known S. spaldingii plants; boom spraying should 

not occur within 15 meters (50 feet), and wiping or 

wicking should be the only herbicide application technique 

employed when within 15 meters (50 feet). Managers may 

want to utilize manual control techniques only when 

within 0.3 meter (1 foot) of individual S. spaldingii plants. 

These suggestions may be adjusted depending on the 

characteristics of the site where they are being employed. 

2.3.1.6.2. Develop set distances for specific herbicides that 

may be employed near known Silene spaldingii sites. 

Persistent chemicals such as picloram should not be used 

within 15 meters (50 feet) of existing Silene spaldingii 

plants. Chemicals that do not affect members of the 

Caryophyllaceae family should be identified and utilized 

whenever possible. These suggestions may be adjusted 

depending on the characteristics of the site where they are 

being employed. 

2.3.1.6.3. Develop guidelines for the timing of herbicide 

applications. Herbicide applications can occur at times 

when the target invasive nonnative plant is susceptible but 

when Silene spaldingii is not susceptible. For example, S. 

spaldingii actively grows from May to September while 

Potentilla recta (sulfur cinquefoil) is active from April to 

October. Herbicide applications to P. recta in April and 

October, when S. spaldingii is dormant, will help to 

minimize effects. 

2.3.2. Conduct fire management activities within Silene spaldingii

habitat. Assessing historical fire frequencies within Silene 

spaldingii habitat (grasslands) is difficult because of the lack of trees 

and tree rings (used to determine fire frequencies). The wide range 

of S. spaldingii also makes analyzing the effects of fire more difficult 

because of the variability in habitats and historical fire regimes. For 
Recovery Plan for Silene spaldingii ● September 2007 

97 

example, unlike the Intermontane Valleys, Canyon and Palouse 

Grasslands may have been stable ecosystems, with species 

composition and distribution not determined by fire (Daubenmire 

1970, p. 7; Tisdale 1986a, p. 35), although fire did still occur in these 

areas. Although there are some areas at higher elevations in the 

Canyon Grasslands that were maintained by fire. Because fire poses 

a threat to humans, fire suppression activities are sometimes 

necessary but should be done so as to minimize damage to S. 

spaldingii to the extent possible. Prescribed burning may enhance 

plant communities and prevent tree encroachment, but may also 

damage S. spaldingii plants or degrade its habitat by accelerating 

nonnative plant invasions or harm native plant communities by 

applying fire at times when plant communities did not historically 

burn. All fire management should be done carefully and with due 

consideration of these factors. 

2.3.2.1. Incorporate fire management plans into habitat 

management plans for all Silene spaldingii populations 

identified as key conservation areas and other areas as 

needed. Fire management should not be done without 

considering impacts to Silene spaldingii and, perhaps more 

importantly, its habitat. Furthermore, fire management plans 

should be considered on a physiographic region basis. For 

example, fire management in Montana’s Intermontane Valleys 

with a thick litter layer and tree encroachment should differ 

significantly from fire management within the Canyon 

Grasslands with a thin litter layer (Hill and Weddell 2003, pp. 

17–18, 23-24; Hill and Gray 2004a, pp. 105-106) and little to no 

problems with tree encroachment (Daubenmire 1970, pp. 7-8; 

Tisdale 1986a, p. 35; Johnson and Simon 1997, pp. 55-56; 

Lesica 1999, p. 1001; Weddell 2001, p. 2). Fire management 

plans should clearly describe strategies to protect S. spaldingii

populations and habitat in the event of a wildfire, during both 

fire-fighting activities and post-fire rehabilitation efforts. Fire 

management plans should be incorporated into habitat 

management plans. The potential for using prescribed or wild 

fire to enhance S. spaldingii habitat, if appropriate, could also 
Recovery Plan for Silene spaldingii ● September 2007 

98 

be included in fire management plans. These fire management 

plans should carefully assess and mimic, as closely as possible, 

historical fire regimes. 

2.3.2.2. Carefully conduct prescribed burns within Silene 

spaldingii habitat. Prescribed burns should be especially 

considered as a management tool for increasing Silene 

spaldingii in areas where Festuca scabrella (rough fescue) is a 

dominant species (Lesica 1997, p. 355). Some have suggested 

that in areas where F. scabrella is not present, the benefits of 

fire may be more questionable. Because of the risk of 

exacerbating invasive nonnative plant populations, prescribed 

burning should be carefully employed across S. spaldingii’s 

range. Prescribed burns should not occur across an entire S. 

spaldingii populations but should instead occur in smaller 

pieces. This should enable managers and land owners to adjust 

burning practices accordingly if problems arise. 

2.3.2.2.1. Conduct surveys for Silene spaldingii before 

prescribed burns are implemented. All prescribed burn 

areas within Silene spaldingii habitat should be surveyed 

for the plant prior to burning. If S. spaldingii is located, 

management activities should be adjusted accordingly 

either by not burning in the area or enacting a monitoring 

program to gauge the plant’s response. 

2.3.2.2.2. Monitor the effects to Silene spaldingii and its 

habitat from all burns. If a fire or a prescribed burn does 

occur where Silene spaldingii resides, trend monitoring 

and possibly demographic monitoring (see actions 2.4.1 

and 2.4.2) studies should be done for 4 years prior to 

burning, whenever possible. Ideally a control plot should 

be part of the monitoring scheme. Post-fire monitoring 

should be done consecutively for 4 years, every 5 years, 

for a monitoring period of at least 15 years after a fire. 

Monitoring should measure both the abundance of S. 

spaldingii as well as habitat characteristics including 
Recovery Plan for Silene spaldingii ● September 2007 

99 

invasive nonnative plant populations. This monitoring is 

needed to understand fire’s effects on S. spaldingii 

recruitment and its habitat. 

2.3.2.2.3. Do not conduct prescribed burns where invasive 

nonnative plant infestations exist unless accompanied 

by an integrated pest management program and 

monitoring. Fire may exacerbate nonnative plant 

invasions (Christensen and Burrows 1986, p. 100; Hobbs 

and Huenneke 1992, pp. 324-325; Lesica and Martin 2003, 

pp. 516, 521). In areas where invasive nonnative plants 

are present, control of or a well formulated integrated pest 

management program for control of invasive nonnative 

plants should be accomplished prior to burning. For 

example, within the Channeled Scablands, prior to 

burning, Bromus tectorum (cheatgrass) cover should be 

less than 20 percent, and all Centaurea solstitialis (yellow 

starthistle), Potentilla recta (sulfur cinquefoil), Chondrilla 

juncea (rush skeletonweed), and Centaurea maculosa

(spotted knapweed) populations should be controlled or 

eliminated. In addition, carefully planned monitoring with 

an unburned control should be implemented prior to 

burning (see action 2.3.2.2.2). 

2.3.3. Protect Silene spaldingii sites from development on public and 

private lands. All Silene spaldingii sites and populations, especially 

key conservation areas, should be protected from development. 

Requirements of the Endangered Species Act should prevent S. 

spaldingii sites from development on Federal lands and Tribal lands 

held in trust by the Federal government. Sites on State lands should 

be protected from development through habitat management plans 

and by needed State designations. Sales to conservation entities may 

also be considered. Populations of S. spaldingii on private land 

should be protected by education and encouragement, conservation 

easements, consideration of deed restrictions, or possibly direct 

acquisition from willing landowners. Working through appropriate 

State, Federal, local, or County agencies, voluntary cooperation 
Recovery Plan for Silene spaldingii ● September 2007 

100 

should be encouraged to protect S. spaldingii habitat on private lands. 

In particular, the conservation and protection of the large population 

on private lands at the north end of Wallowa Lake, Oregon, should 

be encouraged because of its large population size (over 500 

individuals) (ONHP 2006, Element Occurrence 10; Hill and Gray 

2004a, pp. 11, 13). 

2.3.4. Monitor and manage livestock grazing and associated 

management activities to avoid impacts to Silene spaldingii and 

its habitat. All Federal lands with suitable habitat for Silene 

spaldingii should be surveyed in allotments where grazing is 

authorized. Consultation under section 7 of the Endangered Species 

Act should be completed by 2010 for all Federal land allotments with 

suitable habitat for S. spaldingii. If livestock grazing and Silene 

spaldingii co-occur, careful management and monitoring is needed 

(see 2.3.4.1 and 2.3.4.2 below) that includes several site visits during 

the growing season to ensure detrimental effects are not occurring. It 

has been suggested that livestock grazing could be a benefit when a 

thick litter layer has accumulated and prescribed fire may not be used 

(P. Lesica, in litt. 2006, p.3). It has also been suggested that 

livestock utilize the dry areas where Silene spaldingii resides more in 

spring when moisture is available in these areas and that the plant 

may still be able to produce an inflorescence(s) if grazed. Later in 

the season livestock may preferentially eat the inflorescences of 

Silene spaldingii and the plant appears unable to produce another 

inflorescence. 

2.3.4.1. Manage and mitigate livestock grazing and associated 

management activities to avoid and minimize impacts to 

Silene spaldingii and its habitat. Livestock grazing should not 

occur within Silene spaldingii populations, especially at key 

conservation areas, when seedling germination occurs in early 

spring (April and May), during plant emergence and growth 

(May and June), or when the plant is flowering and setting seed 

in late July through September. Careful monitoring that 

demonstrates livestock do not generally utilize areas where S. 

spaldingii resides (i.e. hard to reach because of rocky areas or 
Recovery Plan for Silene spaldingii ● September 2007 

101 

distant from water sources) or demonstrates that population 

numbers are not being deleteriously affected (see 2.3.4.3 below) 

by livestock grazing, may preclude these prescriptions. 

Effective grazing management may include the 

construction and maintenance of fencing, moving watering 

troughs and/or salting areas away from Silene spaldingii 

population, allowing for rest years, and revising allotment 

plans, grazing schedules, and stocking levels to maintain S. 

spaldingii habitat. Management of livestock should be tailored 

to each individual site based on topographic features and 

utilization scenarios. 

Grazing that reduces vegetation by over 50 percent 

should not take place at any time because of the potential 

damage to pollinators, the chance for creating and exacerbating 

invasive nonnative plant problems, and the damages that S. 

spaldingii may incur. Livestock grazing should not occur in S. 

spaldingii pastures where serious invasive nonnative plant 

populations exist unless the invasive nonnative flowers have 

been removed. Responsible parties should evaluate cumulative 

effects of herbivory in areas where both native and domestic 

ungulates graze. 

2.3.4.2. Monitor livestock grazing and associated management 

activities to measure and manage impacts to Silene 

spaldingii and its habitat. Monitoring that can determine 

whether livestock grazing is having an effect on S. spaldingii

should occur at all sites within grazing allotments on a regular 

basis. If populations decline because of adverse livestock 

grazing or trampling, grazing practices should be amended. It is 

recommended that monitoring associated with livestock use 

include paired grazed versus ungrazed transects at each site 

where grazing occurs to adequately determine whether grazing 

is having an effect. In addition, the vegetation community 

should be assessed at each paired plot to determine the effects 

livestock may be having on the habitat. Careful selection of 
Recovery Plan for Silene spaldingii ● September 2007 

102 

paired plots is needed to ensure that trampling or site 

differences are not influencing data. 

Alternative monitoring methods being employed where 

Silene spaldingii resides include: placing “key areas for 

utilization measuring” near Silene spaldingii plants; conducting 

trend monitoring for S. spaldingii without a paired, ungrazed 

site; implementation monitoring; consistent site visits. These 

alternatives should be further discussed as part of the 

monitoring actions (see 2.4 below). Standardized monitoring 

for livestock use should be developed, in as much as possible, 

through the Silene spaldingii technical team. 

2.3.5. Implement effective off-road vehicle use control measures. 

Off-road vehicle use should be effectively controlled in all areas 

containing Silene spaldingii habitat. This may involve the use of 

fencing or other barriers, and developing signs to restrict vehicle use 

to existing, designated roads. Educational signs, oral presentations, 

or other forms of public outreach may be necessary to inform the 

public about the conservation needs of this rare species and raise 

awareness of their responsibility to protect the plant on public lands. 

2.3.6. Monitor and manage wildlife populations and associated 

management activities to avoid impacts to Silene spaldingii and 

its habitat. Analyze the potential effects of wildlife management 

activities on Silene spaldingii sites and habitat. Federal and State 

agencies should monitor and evaluate the effects of wildlife 

populations and associated activities on S. spaldingii. Responsible 

parties should also evaluate cumulative effects of herbivory in areas 

where both native and domestic ungulates graze. 

2.3.7. Avoid herbicide use not related to controlling invasive 

nonnative plant infestations specific to protecting Silene 

spaldingii and all insecticide use within a 1.6 kilometer (1 mile) 

radius of all S. spaldingii populations. Because of the risk of 

herbicides harming S. spaldingii and insecticides harming the 

pollinators of S. spaldingii, a 1.6 kilometer (1 mile) buffer where no 
Recovery Plan for Silene spaldingii ● September 2007 

103 

pesticide use may occur should be utilized whenever possible. In 

sites where populations are near or adjacent to agricultural fields this 

buffer may not be feasible. In these instances precautionary 

measures should be taken to minimize the effects to Silene spaldingii 

populations. These precautionary measures should include 

minimizing or eliminating drift, or the use of pesticides that will not 

harm S. spaldingii or its pollinators.

2.4. Monitor population trends and habitat conditions. Measuring recovery 

will require monitoring of both Silene spaldingii individuals and habitat 

throughout its range in Idaho, Montana, Oregon, and Washington. 

Monitoring will provide information on threats to S. spaldingii habitat, 

population and habitat trends, and will also provide feedback on the 

effectiveness of management and conservation activities. Furthermore, 

monitoring will provide a measurement of when the recovery criteria have 

been met and delisting of S. spaldingii may be considered. In as much as 

possible, a standardized monitoring procedure should be established 

rangewide. 

2.4.1. Monitor Silene spaldingii populations at key conservation areas 

periodically to determine population trends. Responsible agencies 

at potential key conservation areas should ensure that long-term 

monitoring is conducted, beginning within the next 3 years, to 

determine population trends and evaluate habitat conditions at Silene 

spaldingii populations. The effects of adjacent land uses, such as 

recreation, prescribed burns, livestock grazing and trampling, and 

herbicide spraying on this species should be monitored annually. 

Monitoring programs should be designed to evaluate the effects of 

invasive nonnative plants, native ungulate grazing, insect predation 

levels, and other impacts, and be able to document declines at S. 

spaldingii sites. Use of global positioning equipment may be helpful. 

Because of the long-lived nature of the plant and its prolonged 

dormancy, one suggestion is that to adequately assess trends 

monitoring should occur consecutively for 4 or more years every 5 to 

20 years (Lesica and Steele 1994, p. 211). In as much as possible, a 

standardized trend monitoring procedure, coordinated through the 

technical team, should be established rangewide. This will be 
Recovery Plan for Silene spaldingii ● September 2007 

104 

challenging because different areas may require different protocols. 

Because of the difficulties prolonged dormancy presents for 

monitoring, either repeated measures analysis (Lesica and Steele 

1994, p. 211; Lesica and Steele 1996, p. 880; Lesica and Steele 1997, 

p. 336) or mark-recapture methods (Alexander et al. 1997, pp. 1235-

1236; Shefferson et al. 2001, pp. 153-154) should be utilized. This 

standardized trend monitoring procedure should at a minimum 

identify at what time of the year monitoring should occur, 

standardize the minimum acceptable power, a standardized sample 

universe, and standardize age classes. Results from demographic 

monitoring studies in Idaho have found that monitoring should be 

done early in the season soon after emergence when all aboveground 

plants are detectable since some individuals senesce or are eaten 

before flowering (J. Hill, in litt. 2007a). It is important that these 

results be analyzed and reported so they may be shared with other 

parties. 

2.4.2. Conduct demographic monitoring across the range of Silene 

spaldingii. Demographic data (good estimates of demographic 

transition probabilities) allow researchers to predict short-term 

trends, analyze factors that limit population growth and 

establishment (Pavlik 1994, p. 322-350), and are necessary for 

conducting population viability analyses (see Recovery Action 

2.5.1). Because of the long-lived nature of the plant and its 

prolonged dormancy, demographic monitoring should occur 

consecutively for a minimum of 10 consecutive years (P. Lesica, in 

litt. 2007a, pp. 2-3). Careful consideration should be given to both 

aboveground structures that senesce or are eaten by the time 

flowering structures, which should be measured later in the season, 

appear (J. Hill, in litt. 2007a). Not detecting a plant that is present 

aboveground can lead to biased results and erroneous conclusions 

(Kéry and Gregg 2003; Kéry et al. 2005). Also, in some cases, age 

classes cannot be inferred from the aboveground life form. 

Information gained from such studies can be used to guide 

management of Silene spaldingii habitat. Therefore demographic 

studies, dispersed across the range of the plant, are recommended. It 

is important that these results be analyzed and reported so they may 
Recovery Plan for Silene spaldingii ● September 2007 

105 

be shared with other parties. In as much as possible, a standardized 

demographic monitoring procedure should be established rangewide. 

This will be challenging because different areas may require different 

protocols. 

2.4.3. Monitor and evaluate the response of Silene spaldingii to fire 

and invasive nonnative plants. In the event that Silene spaldingii 

sites are burned by wildfire or prescribed burning, annual monitoring 

should be conducted to evaluate the response of S. spaldingii and its 

habitat to fire (see Recovery Action 2.3.2.2.2). If habitat 

rehabilitation or enhancement measures are needed (e.g., to control 

and manage invasive nonnative plants or erosion), these measures 

should be developed in conjunction with the U.S. Fish and Wildlife 

Service, and should be described in site-specific fire management 

plans. The same should be done in association with the incursion of 

invasive nonnative plants. It is important that these results be 

analyzed and reported so they may be shared with other parties. In as 

much as possible, a standardized monitoring procedure should be 

established rangewide (see action 2.4.1 above). This will be 

challenging because different areas may require different protocols. 

2.4.4. Obtain permission from private landowners to conduct 

population trend monitoring for Silene spaldingii on private 

lands. Silene spaldingii sites on private lands should be monitored to 

determine population trends and habitat conditions. Prior to 

conducting monitoring on private lands, permission will be requested 

and obtained from appropriate landowners. In as much as possible, a 

standardized trend monitoring procedure should be established 

rangewide. This will be challenging because different areas may 

require different protocols. 

2.4.5. Determine if sites with no plants have been extirpated. Many 

sites had no Silene spaldingii individuals present when last surveyed. 

Further surveys and methodologies are needed to determine if the 

plants may have been dormant at the time they were last surveyed 

and have since reappeared, or if the species should be considered 

extirpated from these sites. 
Recovery Plan for Silene spaldingii ● September 2007 

106 

2.5. Conduct research essential to the conservation of Silene spaldingii. 

Additional research regarding Silene spaldingii needs to be conducted to 

validate the recovery objectives for this species or to allow for their 

revision, as appropriate. Information on life history, population 

characteristics, and habitat requirements should be obtained to allow for 

more accurate specification of management and population goals. 

Partnerships with other State, Federal, Tribal, or private agencies and 

individuals should be developed, where possible, to meet these objectives. 

We will work with appropriate entities to identify and support the funding 

to conduct essential research on S. spaldingii. 

2.5.1. Determine population viabilities for Silene spaldingii

populations. Conduct essential research, including further genetic 

(including genetic diversity and the loss of genetic variation over 

time) and demographic studies, to determine the long-term 

population viability of Silene spaldingii under various management 

scenarios. A population viability analysis is needed to guide 

management in answering how to manage sites, identifying which 

populations are likely to survive into the future, and which are too 

small and isolated to persist (Menges 1991b, p. 45). Estimates of 

population viability for this species will require data on factors such 

as mortality, dispersal, and recruitment. In addition, habitat 

availability and threats, including manmade or anthropogenic threats, 

natural catastrophes, and genetic and demographic stochasticity 

(Menges 1991b, p. 45) should also be evaluated. A population 

viability analysis may also assist in determining whether the current 

goal of a minimum of 500 reproducing individuals in a potential key 

conservation area and the number of key conservation areas within 

each physiographic region is valid to ensure long-term persistence, 

and allow for refinement of this number, if necessary. 

2.5.2. Develop new populations or supplement existing populations of 

Silene spaldingii where appropriate. Recruitment of Silene 

spaldingii is rare and occurs slowly (P. Lesica, in litt. 2004, p. 6), 

making human intervention necessary to preserve smaller 

populations. Preliminary studies looking at seedling growth indicate 
Recovery Plan for Silene spaldingii ● September 2007 

107 

that growing S. spaldingii in cultivation is a possibility (Lesica 

1988a; 1993; Hill and Gray 2000; 2004a; A. Brusven, University of 

Idaho, in litt. 2004; A. Raven, in litt. 2004). Potential key 

conservation areas where populations will be supplemented or 

developed will need to have plans that address how these activities 

will occur. All new populations and supplementations will be 

conducted on protected areas only. When completed, the population 

viability analysis should assist in identifying what genetic material 

needs to be better conserved. 

2.5.2.1. Utilize existing potential key conservation areas and 

identify new key conservation area sites with good habitat 

where new populations should be developed or where 

existing populations could be supplemented. The time and 

expense of supplementing existing populations and creating 

new populations should be undertaken only at areas that are 

protected and only at areas that have the potential to become 

key conservation areas. Supplementation, reintroduction, and 

introduction should occur only if it will help facilitate the 

recovery of the species and meeting the goals of this recovery 

plan. 

2.5.2.2. Determine the best techniques and develop guidelines for 

creating new populations or supplementing existing 

populations of Silene spaldingii. More research is needed in 

developing the best techniques for successful establishment of 

Silene spaldingii individuals. Seeds seem to germinate easily 

and grow in greenhouse containers. However, techniques to 

successfully transplant individuals to the wild are still needed. 

Furthermore, growing seed as a crop (grow-out) to increase 

seed has not been tested. A grow-out experiment could help in 

providing seed for supplementing or creating new populations 

and minimize impacts to native populations. Guidelines and the 

suitability of re-introduction and introduction activities should 

be periodically evaluated based on new information. 
Recovery Plan for Silene spaldingii ● September 2007 

108 

2.5.2.3. Develop guidelines to ensure genetic conservation during 

supplementation, re-introduction, and introduction 

activities. Use principles of population genetics to guide 

transplanting and reintroduction activities. Additional research 

to describe the genetic variability of S. spaldingii populations 

across the species range may be needed before introduction and 

supplementation efforts can proceed. These efforts should be 

coordinated through the technical team (see action 2.12). 

Guidelines the suitability of re-introduction and introduction 

activities should be periodically evaluated based on new 

information. 

2.5.2.4. Determine the best techniques to restore Silene spaldingii 

habitat. Before populations of Silene spaldingii are created or 

expanded, habitat restoration may be needed to mimic native 

habitat. This native habitat cannot be recreated without 

identifying and practicing the most effective restoration 

techniques. 

2.5.3. Conduct research essential to controlling and managing 

invasive nonnative plants within Silene spaldingii habitat. More 

research is needed in determining the best invasive nonnative plant 

control and management methods within and adjacent to Silene 

spaldingii sites. Subjects for investigation should include the most 

effective herbicides for various invasive nonnative plants; best times 

for herbicide application; the effects of prescribed burning, mowing, 

and biological control agents; and various other techniques that will 

reduce competition from invasive nonnative plants and improve 

habitat for S. spaldingii. 

Additional research is needed to determine the effects of 

nonnative plant invasions on Silene spaldingii. Questions 

investigated should include: which species of invasive nonnative 

plants have the most deleterious effect on S. spaldingii; at which life 

history stage of S. spaldingii is competition from invasive nonnative 

plants most severe; and whether invasive nonnative plants are 
Recovery Plan for Silene spaldingii ● September 2007 

109 

expanding into S. spaldingii habitat where they previously were 

unable to reside.

Research is needed to investigate the best restoration 

techniques to use in degraded Silene spaldingii habitats. Invasive 

nonnative plants may be better detected if remote sensing techniques 

are identified that can detect invasive nonnative plant populations in 

locations that are difficult to access by foot or vehicle. 

2.5.4. Conduct research essential to managing livestock, wildlife, and 

insect herbivory at Silene spaldingii populations. Herbivory of 

Silene spaldingii occurs at all sites where S. spaldingii resides. The 

plant has adapted to some herbivory over the course of evolutionary 

time, while other herbivory is new or may have increased as a result 

of human activities. Research is needed to determine at what levels 

of herbivory S. spaldingii plants can persist, and at what levels its 

habitat remains intact. Also research is needed to address whether 

under some conditions where prescribed fire may not be utilized and 

litter has accumulated, livestock grazing could be used as a tool to 

enhance S. spaldingii populations. Livestock grazing is the most 

obvious form of human-related herbivory. 

Information is needed on how differences in duration, 

intensity, and seasonality of herbivory, particularly livestock grazing 

and trampling, impact Silene spaldingii, its habitat, and nonnative 

plant invasions. Aside from livestock grazing and trampling, 

herbivory effects from wildlife species that may be at higher than 

historical levels need investigation. Finally, insect and small 

mammal herbivory needs further investigation. For example, to 

what extent is the presence of invasive nonnative plants increasing or 

decreasing natural insect herbivory levels. 

2.5.5. Conduct research to better determine the effects of fire on 

Silene spaldingii and identify when and where prescribed fire 

should occur, particularly outside of Montana. Information is 

needed on how fires conducted during various seasons, the presence 

of invasive nonnative plants, and various habitat types affect Silene 
Recovery Plan for Silene spaldingii ● September 2007 

110 

spaldingii, its recruitment rates, its habitat, and nonnative plant 

invasions. For example, because litter build-up varies, do fires 

within the Canyon Grasslands and their effects on S. spaldingii differ 

from those at the Dancing Prairie Preserve in Montana, where 

research has already occurred? Which invasive nonnative plants 

benefit from fire and which are affected deleteriously? At what 

densities do invasive nonnative plants proliferate with fire and at 

what densities do they decline? Are these densities different across 

various habitat types? Is tree encroachment into grasslands a 

problem across the range of S. spaldingii? What are the effects to S. 

spaldingii and its habitats from prescribed fires that typically occur 

outside of the historical fire season? Since some research on fire 

effects has already taken place on S. spaldingii populations in 

Montana, such studies are particularly needed in other areas within 

the species’ range. 

An accurate method of measuring historical fire frequency 

within grassland habitats is needed. In addition, research on the 

effects of fire on Symphoricarpos albus (snowberry) and Rosa spp. 

(rose) is needed to determine if fire encourages these browse 

species, as has been suggested by wildlife managers. 

2.5.6. Conduct further research regarding reproductive biology and 

essential pollinators for Silene spaldingii. Research is needed to 

better separate self-incompatibility mechanisms from inbreeding 

depression and to determine if Silene spaldingii is capable of creating 

seed without the addition of pollen (apomixis). No research has 

investigated if outbreeding depression may be problematic for S. 

spaldingii. Information on outbreeding depression would be useful 

in reintroduction experiments. 

Because pollinators are required for full seed set of Silene 

spaldingii (Lesica 1988b, p. 5; 1993, p. 198; Lesica and Heidel 1996, 

p. 9), conservation measures should be designed to protect nearby 

pollinator populations. Research is needed to better design 

conservation measures that protect pollinators. Additional 

information on the requirements of pollinators, especially Bombus 
Recovery Plan for Silene spaldingii ● September 2007 

111 

fervidus, is needed, including the locations of nests, queen 

overwintering sites, preferred habitats, and resource competition. 

Research investigating how far Bombus fervidus is capable of 

transporting pollen as well as the relative contributions of other 

pollinators is needed. The effects of threats including adverse 

livestock grazing and trampling, and fire on S. spaldingii’s ground 

dwelling pollinators should be studied. 

2.5.7. Conduct research investigating seed dispersal mechanisms for 

Silene spaldingii. No studies have investigated seed dispersal 

mechanisms for Silene spaldingii. Research is needed to determine 

how S. spaldingii seeds are transported, what transports seeds, and 

how far seeds are generally transported. This information is needed 

to conserve dispersal mechanisms, and to develop a better 

understanding of gene dispersal and what constitutes a discrete 

population. 

2.5.8. Conduct research on soil seed bank ecology including seed 

longevity, seed viability, and genetics. No studies have 

investigated how long Silene spaldingii seeds may remain viable in 

the ground. This information is important because if seeds are viable 

for only a year or two, the loss of one year’s seed production to fire 

or herbivory will dramatically reduce the amount of seed available 

for recruitment. 

2.5.9. Conduct further genetic research including genetic diversity 

and gene flow across Silene spaldingii’s range. Baldwin and 

Brunsfeld’s (1995) genetic study was only preliminary; they made a 

number of recommendations for further genetic work. First, genetic 

material should be collected from a wider range of samples and 

analyze more loci during a moist year when sample sizes can be large 

enough to more definitely make conclusions about the dispersal of 

genes across the range of Silene spaldingii (Baldwin and Brunsfeld 

1995, p. 7). And second, the higher homozygosity levels and lower 

pollinator visitation rates at the Dancing Prairie site need to be 

further investigated (Baldwin and Brunsfeld 1995, p. 7). 
Recovery Plan for Silene spaldingii ● September 2007 

112 

In addition, genetic research is needed that investigates the 

effects of small population size, fragmentation, and genetic isolation. 

Genetic analyses should help to identify high priority populations for 

conservation efforts, which populations should be used to found new 

populations, the suitability of preservation based on key conservation 

areas, and should be incorporated with the population viability 

analysis identified in Recovery Action 2.5.1 above. Finally, 

investigations of the genetic reservoir represented by the soil seed 

bank would further clarify the overall genetic diversity of the species 

and assist managers in assessing the importance of the seed bank to 

future conservation of the species. 

2.6. Conduct surveys in potential habitat areas. Manage and protect any 

newly discovered Silene spaldingii populations. Intensive field work 

should be conducted to locate additional populations of this species, 

especially within the Canyon Grasslands. The habitat of any newly 

discovered populations should be protected and managed as necessary. 

Habitat models are often utilized to prioritize where surveys should occur 

for rare species. To date, habitat models for S. spaldingii have resulted in 

large areas of suitable habitat. These large areas are then difficult to 

prioritize. Better habitat models are need for further refining and 

prioritizing survey efforts. Because the Canyon Grasslands are extremely 

steep and quite remote, there are still significant portions of suitable 

habitat to be searched, particularly on the Oregon side of the Snake River 

directly across from Craig Mountain, along the lower Grande Ronde River 

in Oregon and Washington, the Imnaha River in Oregon, and the lower 

Clearwater and Salmon Rivers in Idaho (summarized in Hill and Gray 

2004a, pp. 17-21). Over 40 percent of known S. spaldingii sites are on 

private land; in general, these private lands have had much less inventory 

effort. The possibility for large populations residing on private property 

can not be overlooked. Several recent Bureau of Land Management land 

acquisitions in Washington (B. Benner, in litt. 2003, p. 6), as well as The 

Nature Conservancy’s acquisition in 2000 of the Zumwalt Prairie 

Preserve, have led to the discovery of large, previously unknown S. 

spaldingii populations. 
Recovery Plan for Silene spaldingii ● September 2007 

113 

2.6.1. Conduct surveys on Federal lands for Silene spaldingii. 

Intensive surveys for Silene spaldingii should be conducted prior to 

approving and implementing activities that may affect habitat (either 

occupied or potentially suitable) for this species in the Canyon 

Grasslands, Palouse Grasslands, Channeled Scablands, Blue 

Mountain Basins, and Intermontane Valleys. Discovering new and 

large populations of S. spaldingii, especially within intact habitat, 

will help meet delisting goals. Surveys are especially needed within 

the Canyon Grasslands where it is surmised populations may reside 

with minimal threats. Surveys should also be conducted in areas 

where ongoing activities such as livestock grazing or trampling may 

adversely affect known or potentially suitable habitat for S. 

spaldingii on Federal lands, and whenever possible on State, Tribal, 

and private lands as well. 

2.6.2. Conduct surveys on State and Tribal lands, especially where 

activities may affect Silene spaldingii habitat. Surveys are needed 

on both Tribal and State lands. Staff and funding should be 

identified to accomplish these activities. 

2.6.3. Obtain permission from private landowners to conduct surveys 

for Silene spaldingii on private lands. Prior to conducting surveys 

on private lands, permission will be requested and obtained from 

appropriate landowners. 

2.6.4. Protect newly discovered Silene spaldingii populations. Newly 

discovered populations should be granted the same protection as 

already discovered sites, and recovery tasks included here should 

apply to these newly discovered sites. 

2.7. Support conservation on privately owned lands. Over 50 percent of the 

known populations of Silene spaldingii are on lands not managed by 

Federal, Tribal, or State entities (Hill and Gray 2004a, pp. 7, 14). Because 

the Endangered Species Act does not require surveys of S. spaldingii on 

private land, it is expected that many S. spaldingii sites remain 

unidentified or unreported on private lands. One of the seven known 

populations with over 500 individuals is currently unprotected on private 
Recovery Plan for Silene spaldingii ● September 2007 

114 

lands. Three populations with over 500 individuals are located either 

wholly or partially on lands managed by The Nature Conservancy, a 

private conservation organization. Participation with private landowners is 

needed for successful conservation of S. spaldingii. Participation from 

private landowners is not required by the Endangered Species Act; 

therefore, outreach activities are needed to encourage voluntary 

conservation on private lands. 

2.7.1. Support conservation actions on lands owned by The Nature 

Conservancy. The Nature Conservancy has been vital in 

conservation of Silene spaldingii. The largest population of S. 

spaldingii is located on The Nature Conservancy’s Dancing Prairie 

Preserve (Mincemoyer 2005, p. 10). The Zumwalt Prairie Preserve 

in Oregon and the Garden Creek Ranch in Idaho also have large 

populations of S. spaldingii (ONHP 2006, Element Occurrences 7, 

22, 28-36; ICDC 2007, Element Occurrence 6). Many research and 

monitoring studies have been conducted and funded on these parcels 

of land. The action items listed here should apply to S. spaldingii

sites on The Nature Conservancy lands. A volunteer registry of S. 

spaldingii populations on private lands, such as the one The Nature 

Conservancy maintains in Washington and Montana, should be 

implemented and updated in all States where S. spaldingii resides. 

Registry lands should be considered for permanent easements that 

protect S. spaldingii. 

2.7.2. Support conservation activities on other private lands. Key 

conservation areas on private land, such as those along Wallowa 

Lake in Oregon, should be identified where conservation of Silene 

spaldingii is needed. Appropriate landowners should be contacted 

and potential conservation activities identified and implemented 

whenever possible. Recommendations for protection on private 

lands are included in Recovery Actions 2.1, 2.2, 2.3, 2.3.3, 2.4, 2.4.4, 

and 2.7.1. Programs available to fund conservation activities and/or 

acquisitions on private lands include the U.S. Fish and Wildlife 

Service’s Partners for Fish and Wildlife Program, Private 

Stewardship Grants, Recovery Land Acquisition Grants, and 

Landowner Incentive Program; and the Natural Resource 
Recovery Plan for Silene spaldingii ● September 2007 

115 

Conservation Service’s Environmental Quality Incentives Program, 

Wildlife Habitat Incentives Program, Conservation Reserve Program, 

and Grassland Reserve Program. In addition, State agencies may 

have programs that provide incentives for conservation. 

2.7.3. Conduct outreach and awareness efforts with the public 

regarding Silene spaldingii’s plight and its conservation. Without 

outreach and awareness activities, the public will not know about 

Silene spaldingii or its conservation needs. Written outreach material 

is needed in the form of newspaper articles, pamphlets, and displays 

at public meetings. Oral presentations are needed to groups 

concerned with invasive nonnative plant control (see Recovery 

Action 2.3.1.3), native plant societies, Master Gardeners, Natural 

Resource Conservation Service personnel, County conservation 

committees, Soil and Water Conservation Districts, Cooperative 

Extension Agencies, and others to reach the public. In areas 

experiencing impacts from off highway vehicle (OHV) use, specific 

outreach programs should be aimed at local OHV groups, businesses, 

and events. 

2.8. Pursue land and species designations that will help facilitate 

conservation of Silene spaldingii. Federal agencies should consider 

designating important Silene spaldingii habitat areas on public land as 

special management areas (e.g., as Areas of Critical Environmental 

Concern, Botanical Special Interest Areas, or Research Natural Areas). 

Protected habitat areas should include occupied habitat and potentially 

suitable, currently unoccupied habitat to allow for population expansion, 

especially near key conservation areas. Recommendations for special 

management designations should be incorporated into S. spaldingii habitat 

management plans. Because S. spaldingii is not protected on State 

managed lands, protection of the species occurs only through the good will 

of State managers (the exception is in Oregon, where the species is 

technically protected; however, no populations of S. spaldingii are known 

to occur on State lands in Oregon). State legislation is recommended to 

better protect the species on State managed lands. This legislation should 

also serve to protect the plant on lands owned by educational institutions 

that receive State funding. In Washington, mechanisms exist to acquire 
Recovery Plan for Silene spaldingii ● September 2007 

116 

land from willing landowners and designate the land as Natural Area 

Preserves, which are then managed specifically for the species or 

ecosystem of interest at the site. 

2.9. Establish propagule banks, including a long-term seed storage facility 

for Silene spaldingii. Silene spaldingii seeds have been collected from 

only six populations, all of which are relatively large. Seeds of S. 

spaldingii should be collected according to currently accepted protocol 

from all populations, and stored at a long-term seed storage facility such as 

the Berry Botanic Garden in Portland, Oregon. Seeds should be collected 

in coordination with seed storage facilities to capture as much of the 

species’ genetic variability as possible. Seeds should be collected from 

representative populations throughout the range of the species starting 

with all small, isolated populations and those on private lands to conserve 

genetic diversity. The U.S. Fish and Wildlife Service will assist with 

securing permits for activities as appropriate. 

2.10. Secure funding for implementation of recovery actions. Additional 

funding over the long-term will be needed to implement the recovery 

actions listed here. Each land manager or owner will be responsible for 

securing funding to protect Silene spaldingii. Collaborative efforts 

between agencies and individuals will be necessary to accomplish larger 

actions such as surveying the Canyon Grasslands. 

2.11. Validate and revise recovery objectives. This recovery plan should be 

updated as recovery actions are accomplished, or revised as additional 

information becomes available. In particular, the results of any population 

viability analyses conducted for Silene spaldingii will be considered in 

future recovery plan revisions. 

2.12. Convene annual meetings of the Silene spaldingii technical team. 

Annual meetings or conference calls of the S. spaldingii technical team 

should be conducted. The technical team should be composed of 

interested individuals and organizations. These annual meetings should 

inform other members of ongoing S. spaldingii conservation actions, and 

serve as a forum to discuss, coordinate, evaluate, and prioritize recovery 

actions.
Recovery Plan for Silene spaldingii ● September 2007 

117 

3. Develop a post-delisting monitoring plan. A plan for monitoring the species 

for a minimum of 5 years after delisting must be in place and ready for 

implementation at the time of delisting. Such a plan will ensure the ongoing 

recovery of the species and provide a means of assessing the effectiveness of 

management actions. 
Recovery Plan for Silene spaldingii ● September 2007 

118 

IV. Implementation Schedule 

The Implementation Schedule that follows outlines the recommended 

recovery actions and estimated time and costs of the recovery program for Silene 

spaldingii, as set forth in this recovery plan. It is a guide for meeting the recovery 

goals outlined in this plan. The schedule indicates action priorities, action 

numbers, action descriptions, duration of actions, the parties responsible for 

actions, and estimated costs. Parties with the authority, responsibility, or 

expressed interest to implement a specific recovery action are identified in the 

Implementation Schedule. When more than one party has been identified, the 

proposed lead party is indicated by an asterisk (*). The listing of a party in the 

Implementation Schedule does not require the identified party to implement the 

action(s) or to secure funding for implementing the action(s). 

Definition of Action Priorities: 

Priority 1 - An action that must be taken to prevent extinction or to prevent 

the species from declining irreversibly in the foreseeable future. 

Priority 2 - An action that must be taken to prevent a significant decline in 

species population or habitat quality, or some other significant negative 

impact short of extinction. 

Priority 3 - All other actions necessary to meet the recovery objectives. 

Definition of Action Durations: 

Continual - An action that will be implemented on a routine basis once begun. 

Ongoing - An action that is currently being implemented and will continue 

until the action is no longer necessary. 

Estimated Costs: 

Continual and ongoing costs, as well as the estimated total cost, are based 

on a projected 34-year timeframe to recovery and delisting of the species. 

Because Silene spaldingii is a long-lived perennial species and annual counts vary 
Recovery Plan for Silene spaldingii ● September 2007 

119 

significantly in response to climatic events, a minimum of 20 years of monitoring 

is needed to determine long-term population trends. The estimated projected 

recovery date of 2040 reflects the need for this long-term monitoring as well as 

the time it may take to supplement or establish new populations. 

Key to Responsible Parties: 

BBG Berry Botanic Garden 

BLM Bureau of Land Management 

CSKT Confederated Salish and Kootenai Tribes 

CBLM Cottonwood Field Office, Bureau of Land Management, Idaho 

CMWMA Craig Mountain Wildlife Management Area, Idaho Department of 

Fish and Game 

DPP Dancing Prairie Preserve, The Nature Conservancy 

DOD Department of Defense 

DOT Department of Transportation 

EDU Higher education facilities 

FAFB Fairchild Air Force Base 

FS U.S. Forest Service 

GCR Garden Creek Ranch, The Nature Conservancy 

HP Heritage Programs and Conservation Data Centers 

IDL Idaho Department of Lands 

LTNWR Lost Trail National Wildlife Refuge 

MSTL Montana State Trust Lands 

NRCS Natural Resource Conservation Service 

NPT Nez Perce Tribe 

OCJG Old Chief Joseph Gravesite, Nez Perce National Historic Park 

PVT Private landowners 

SWCD Soil and Water Conservation District 

SBLM Spokane District Bureau of Land Management, Washington 

ST State land management agencies 

SLWA Swanson Lakes Wildlife Area, Washington Department of Fish 

and Wildlife 

T Native American Tribes 

TNC The Nature Conservancy 

TNWR Turnbull National Wildlife Refuge 

UNF Umatilla National Forest 

USFWS U.S. Fish and Wildlife Service 

VBLM Vale District Bureau of Land Management, Oregon 

WWNF Wallowa-Whitman National Forest 

WNHP Washington Natural Heritage Program 

WMA Weed Management Areas 

WHISP Wild Horse Island State Park, Montana Fish, Wildlife, and Parks 

ZPP Zumwalt Prairie Preserve, The Nature Conservancy 
120 

Implementation Schedule for the Silene spaldingii Recovery Plan 

Cost Estimates ($1,000) Priority 

Number 

Action 

Number 

Action Description Action 

Duration 

(years) 

Responsible 

Parties Total 

CostH

FY 

2007 

FY 

2008 

FY 

2009 

FY 

2010 

FY 

201

1 1.1.1 

Conserve and work to enhance the four Silene spaldingiipopulations within the Blue Mountain Basins identified here as potential key conservation areas. 

Ongoing 

EDU, NRCS, 

OCJG, PVT, 

SWCD, 

USFWS*, 

WWNF, ZPP 

1 1.1.4 

Control and manage invasive nonnative plant species specific to the Blue Mountain Basins. 

Ongoing 

OCJG, PVT, 

USFWS, 

VBLM, WMA, 

WWNF*, ZPP 

102 3 3 3 3 3 

1 1.2.1 

Conserve, identify, and work to enhance the five Silene spaldingii populations within the Canyon Grasslands identified here as potential key conservation areas. 

Ongoing 

CBLM, 

CMWMA, 

EDU, GKR, 

NPT, UNF, 

USFWS*, 

WWNF 

1 1.2.4 

Control and manage invasive nonnative plant species specific to the Canyon Grasslands. Ongoing 

CBLM, 

CMWMA, 

GKR, NPT, 

PVT, ST, UNF, 

USFWS, 

WMA*, WWNF

102 3 3 3 3 3 

1 1.3.1 

Conserve, survey, and work to enhance seven Silene spaldingii populations within 

the Channeled Scablands identified here as potential key conservation areas. 

Ongoing 

NRCS, PVT, 

SBLM*, 

SLWA, SWCD, 

USFWS 
121 

Implementation Schedule for the Silene spaldingii Recovery Plan 

Cost Estimates ($1,000) Priority 

Number 

Action 

Number 

Action Description Action 

Duration 

(years) 

Responsible 

Parties Total 

CostH

FY 

2007 

FY 

2008 

FY 

2009 

FY 

2010 

FY 

201

1 1.3.4 

Control and manage invasive nonnative plant species specific to the Channeled Scablands. 

Ongoing 

FAFB, PVT, 

SBLM*, 

SLWA, TNWR, 

USFWS, WMA

102 3 3 3 3 3 

1 1.4.1 

Conserve and work to enhance three Silene spaldingiipopulations within the Intermontane Valleys identified here as potential key conservation areas. 

Ongoing 

CSKT, DPP, 

EDU, LTNWR, 

PVT, ST, 

USFWS*, 

WHISP 

1 1.4.2 

Conduct further surveys or work to supplement existing populations within the Intermontane Valleys to achieve at least one additional potential key conservation areas with over 500 individuals. 

Ongoing 

CSKT, EDU, 

FS, LTNWR, 

MSTL, NRCS, 

PVT, ST, 

SWCD, 

USFWS* 

1 1.4.4 

Control and manage invasive nonnative plant species specific to the Intermontane Valleys. Ongoing 

CSKT, DPP, FS, 

LTNWR, 

MSTL, PVT, 

ST, USFWS*, 

WHISP, WMA

102 3 3 3 3 3 
122 

Implementation Schedule for the Silene spaldingii Recovery Plan 

Cost Estimates ($1,000) Priority 

Number 

Action 

Number 

Action Description Action 

Duration 

(years) 

Responsible 

Parties Total 

CostH

FY 

2007 

FY 

2008 

FY 

2009 

FY 

2010 

FY 

201

1 1.5.1 

Conserve and work to enhance the three Silene spaldingii

populations within the Palouse Grasslands identified here as potential key conservation areas. 

Ongoing 

EDU, NRCS, 

PVT, SWCD, 

USFWS*, 

WSU, NPT 

1 1.5.3 

Supplement existing populations and conduct a restoration and reintroduction program within the Palouse Grasslands to achieve the goal of three key conservation areas of Silene spaldingii with over 

500 individuals. 

Ongoing 

CBLM, EDU, 

NRCS, PVT, 

SBLM, ST, 

SWCD, 

USFWS*, WSU

1 1.5.5 

Control and manage invasive nonnative plant species specific to the Palouse Grasslands. 

Ongoing 

CBLM, PVT, 

SBLM, ST, 

USFWS*, 

WMA, WSU 

34 1 1 1 1 1 

1 2.10 

Secure funding for implementation or recovery tasks. 

Continual All 
123 

Implementation Schedule for the Silene spaldingii Recovery Plan 

Cost Estimates ($1,000) Priority 

Number 

Action 

Number 

Action Description Action 

Duration 

(years) 

Responsible 

Parties Total 

CostH

FY 

2007 

FY 

2008 

FY 

2009 

FY 

2010 

FY 

201

1 2.2 

Develop Silene spaldingiispecific habitat management plans at all key conservation areas. 

6 

CBLM, 

CMWMA, 

CSKT, DDP, 

GKR, LTNWR, 

OCJG, PVT, 

SBLM, SLWA, 

UNF, USFWS*, 

WHISP, WSU, 

WWNF, ZPP, 

NPT 

480 40 40 40 40 40 

1 2.3.1.2 

Conduct invasive nonnative plant control and management measures at all key conservation areas and other populations as needed. 

Continual All 

1 2.3.3 

Protect Silene spaldingii sites 

from development on public and private lands. 

Continual All 204 6 6 6 6 6 

1 2.5.2.2 

Determine the best techniques for creating new populations or supplementing existing populations of Silene spaldingii. 

10 

BLM, DOD, 

EDU, FS, ST, T, 

TNC, USFWS*

40 4 4 4 4 4 

1 2.5.2.3 

Develop guidelines to ensure genetic conservation during supplementation, reintroduction, and introduction activities. 

5 

BLM, DOD, 

EDU, FS, ST, T, 

TNC, USFWS*

50 10 10 10 10 10 
124 

Implementation Schedule for the Silene spaldingii Recovery Plan 

Cost Estimates ($1,000) Priority 

Number 

Action 

Number 

Action Description Action 

Duration 

(years) 

Responsible 

Parties Total 

CostH

FY 

2007 

FY 

2008 

FY 

2009 

FY 

2010 

FY 

201

1 2.5.2.4 

Determine the best techniques to restore Silene spaldingiihabitat. 

Continual 

BLM, DOD, 

EDU, FS, ST, T, 

TNC, USFWS*

170 5 5 5 5 5 

1 2.5.9 

Conduct further genetic research including genetic diversity and gene flow across Silene spaldingii’s range. 

5 

BLM, DOD, 

EDU, FS, ST, T, 

TNC, USFWS*

100 20 20 20 20 20 

1 2.6.4 Protect newly discovered Silene spaldingii populations. Continual All 1 2.9 

Establish propagule banks, including a long-term seed storage facility for Silene spaldingii. 

Ongoing All, BBG* 34 1 1 1 1 1 

2 1.1.2 

Conduct further surveys to identify, or work to create, at least one new population and key conservation area within the Blue Mountain Basins with over 500 individuals. 

Ongoing 

EDU, NRCS, 

OCJG, PVT, 

SWCD, 

USFWS*, 

VBLM, 

WWNF, ZPP 

2 1.2.2 

Conduct further surveys to identify at least two new populations and potential key conservation areas within the Canyon Grasslands with over 500 individuals. 

Ongoing 

CBLM, 

CMWMA, 

EDU, GKR, 

IDL, NPT, PVT, 

SBLM, ST, 

UNF, USFWS*, 

VBLM, WWNF
125 

Implementation Schedule for the Silene spaldingii Recovery Plan 

Cost Estimates ($1,000) Priority 

Number 

Action 

Number 

Action Description Action 

Duration 

(years) 

Responsible 

Parties Total 

CostH

FY 

2007 

FY 

2008 

FY 

2009 

FY 

2010 

FY 

201

2 1.3.2 

Conduct further surveys to identify, or work to create, at least one new population and key conservation area within the Channeled Scablands with over 500 individuals. 

Ongoing 

FAFB, PVT, 

SBLM*, 

SLWA, TNWR, 

USFWS, WMA

2 1.4.2 

Conduct further surveys or work to supplement existing populations within the Intermontane Valleys to achieve two additional potential key conservation areas with over 500 individuals. 

Ongoing 

CSKT, EDU, 

FS, LTNWR, 

MSTL, NRCS, 

PVT, ST, 

SWCD, 

USFWS* 

2 2.3.1.5 

Conduct surveys for Silene spaldingii before invasive nonnative plant control measures are implemented. 

Ongoing All 612 18 18 18 18 18 

2 2.3.1.6.1 

Develop set distances where various herbicide application techniques may be used near Silene spaldingii plants. 

Once every 

5 years 

BLM, FS, ST, 

USFWS*, 

WMA 

7 1 

2 2.3.1.6.2 

Develop set distances for specific herbicides that may be employed near known Silene spaldingii sites. 

Once every 

5 years 

BLM, FS, ST, 

USFWS*, 

WMA 

7 1 
126 

Implementation Schedule for the Silene spaldingii Recovery Plan 

Cost Estimates ($1,000) Priority 

Number 

Action 

Number 

Action Description Action 

Duration 

(years) 

Responsible 

Parties Total 

CostH

FY 

2007 

FY 

2008 

FY 

2009 

FY 

2010 

FY 

201

2 2.3.1.6.3 

Develop guidelines for the timing of herbicide applications. 

Ongoing; 

once every 

5 years 

BLM, EDU, FS, 

ST, USFWS*, 

WMA 

7 1 

2 2.3.2.1 

Incorporate fire management plans into habitat management plans for all Silene spaldingiipopulations identified as key conservation areas and other areas as needed. 

6 Same as Action 2.2 

2 2.3.2.2.1 

Conduct surveys for Silene spaldingii before prescribed burns are implemented. Ongoing All 612 18 18 18 18 18 

2 2.3.2.2.3 

Do not conduct prescribed burns where invasive nonnative plant infestations exist unless accompanied by an integrated pest management program and monitoring. 

Ongoing All 

2 2.3.4 

Monitor and manage livestock grazing and associated management activities to avoid impacts to Silene spaldingiiand its habitat. 

Ongoing All 442 13 13 13 13 13 

2 2.3.5 

Implement effective off-road vehicle use control measures. Continual All 170 5 5 5 5 5 
127 

Implementation Schedule for the Silene spaldingii Recovery Plan 

Cost Estimates ($1,000) Priority 

Number 

Action 

Number 

Action Description Action 

Duration 

(years) 

Responsible 

Parties Total 

CostH

FY 

2007 

FY 

2008 

FY 

2009 

FY 

2010 

FY 

201

3 1.1.3 

Conserve and protect smaller populations within the Blue Mountain Basins. Ongoing 

EDU, NRCS, 

OCJG, PVT, 

SWCD, 

USFWS*, 

VBLM, 

WWNF, ZPP 

3 1.2.3 

Conserve and protect smaller populations within the Canyon Grasslands. 

Ongoing 

CBLM, 

CMWMA, 

EDU, GKR, 

IDL, NPT, PVT, 

SBLM, ST, 

UNF, USFWS*, 

VBLM, WWNF

3 1.3.3 

Conserve and protect smaller populations within the Channeled Scablands. Ongoing 

FAFB, PVT, 

SBLM*, 

SLWA, TNWR, 

USFWS, WMA

3 1.4.3 

Conserve and protect smaller populations within the Intermontane Valleys. Ongoing 

CSKT, EDU, 

FS, LTNWR, 

MSTL, NRCS, 

PVT, ST, 

SWCD, USFWS

3 1.5.4 

Conserve and protect smaller populations within the Palouse grasslands. Ongoing 

CBLM, PVT, 

SBLM, ST, 

USFWS*, 

WMA, WSU 
128 

Implementation Schedule for the Silene spaldingii Recovery Plan 

Cost Estimates ($1,000) Priority 

Number 

Action 

Number 

Action Description Action 

Duration 

(years) 

Responsible 

Parties Total 

CostH

FY 

2007 

FY 

2008 

FY 

2009 

FY 

2010 

FY 

201

3 1.5.2 

Conduct a study identifying intact habitat within the Palouse Grasslands where Silene spaldingii may occur and follow with surveys for the plant. 

5 

CBLM, EDU, 

PVT, SBLM, 

ST, USFWS*, 

WSU, NPT 

20 4 4 4 4 4 

3 2.1 

Revise and implement general management plans to include Silene spaldingii where the species resides. 

As plans 

are revised

BLM, EDU, 

FAFB, FS, 

OCJG, ST, T, 

TNC, USFWS* 

100 10 10 10 10 10 

3 2.3.1.1 

Incorporate integrated pest management programs into habitat management plans for Silene spaldingii at all key conservation areas and other areas as needed. 

6 Same as Action 2.2 

3 2.3.1.3 

Ensure invasive nonnative plant control and management measures are coordinated with appropriate agencies. 

Ongoing All 

3 2.3.1.4 

Conduct outreach activities for individuals or organizations that are involved in controlling and managing invasive nonnative plants. 

Ongoing All, USFWS* 34 1 1 1 1 1 

3 2.3.2.2.2 

Monitor the effects to Silene spaldingii and its habitat from all burns. 

Ongoing All 340 10 10 10 10 10 
129 

Implementation Schedule for the Silene spaldingii Recovery Plan 

Cost Estimates ($1,000) Priority 

Number 

Action 

Number 

Action Description Action 

Duration 

(years) 

Responsible 

Parties Total 

CostH

FY 

2007 

FY 

2008 

FY 

2009 

FY 

2010 

FY 

201

3 2.3.6 

Monitor and manage wildlife populations and associated management activities to avoid impacts to Silene spaldingiiand its habitat. 

Continual BLM, FS, ST*, T 68 2 2 2 2 2 

3 2.3.7 

Avoid herbicide use not related to controlling invasive nonnative plant infestations specific to protecting Silene spaldingii and all insecticide use within a 1.6 kilometer (1 mile) radius of all S. spaldingii populations. 

Ongoing All 

3 2.4.1 

Monitor Silene spaldingii

populations at key conservation areas periodically to determine population trends. 

Continual Same as Action 2.2 1,632 48 48 48 48 48 

3 2.4.2 

Conduct demographic monitoring across the range of Silene spaldingii. 

At least 10 

years 

Same as Action 

2.2 450 30 30 30 30 30 

3 2.4.3 

Monitor and evaluate the response of Silene spaldingiito fire and invasive nonnative plants. 

Ongoing All 
130 

Implementation Schedule for the Silene spaldingii Recovery Plan 

Cost Estimates ($1,000) Priority 

Number 

Action 

Number 

Action Description Action 

Duration 

(years) 

Responsible 

Parties Total 

CostH

FY 

2007 

FY 

2008 

FY 

2009 

FY 

2010 

FY 

201

3 2.4.4 

Obtain permission from private landowners to conduct population trend monitoring for Silene spaldingii on private lands. 

Continual 

BLM, EDU, FS, 

HP, NRCS, 

PVT, USFWS*

3 2.4.5 

Determine if sites with no plants have been extirpated. 3 BLM, EDU, FS, HP, NRCS, 

PVT, USFWS*

6 2 2 2 

3 2.5.1 

Determine population viabilities for Silene spaldingii

populations. 15 

BLM, EDU, FS, 

ST, TNC, 

USFWS* 

20 

3 2.5.2.1 

Utilize existing key conservation areas and identify new key conservation areas with good habitat where new populations should be developed or where existing populations could be supplemented. 

Continual All 510 15 15 15 15 15 

3 2.5.3 

Conduct research essential to controlling and managing invasive nonnative plants within Silene spaldingiihabitat. 

Continual 

BLM, DOD, 

EDU, FS, ST, T, 

TNC, USFWS*

170 5 5 5 5 5 
131 

Implementation Schedule for the Silene spaldingii Recovery Plan 

Cost Estimates ($1,000) Priority 

Number 

Action 

Number 

Action Description Action 

Duration 

(years) 

Responsible 

Parties Total 

CostH

FY 

2007 

FY 

2008 

FY 

2009 

FY 

2010 

FY 

201

3 2.5.4 

Conduct research essential to managing livestock, wildlife, and insect herbivory at Silene spaldingii populations. 

20 

BLM, DOD, 

EDU, FS, ST, T, 

TNC, USFWS*

200 10 10 10 10 10 

3 2.5.5 

Conduct research to better determine the effects of fire on Silene spaldingii and identify when and where prescribed fire should occur, particularly outside of Montana. 

20 

BLM, DOD, 

EDU, FS, ST, T, 

TNC, USFWS*

200 10 10 10 10 10 

3 2.5.6 

Conduct further research regarding reproductive biology and essential pollinators for Silene spaldingii. 

3 

BLM, DOD, 

EDU, FS, ST, T, 

TNC, USFWS*

18 6 6 6 

3 2.5.7 

Conduct research investigating seed dispersal mechanisms for Silene spaldingii. 

5 

BLM, DOD, 

EDU, FS, ST, T, 

TNC, USFWS*

10 2 2 

3 2.5.8 

Conduct research on soil seed bank ecology including seed longevity, seed viability, and genetics. 

Depends on 

longevity 

BLM, DOD, 

EDU, FS, ST, T, 

TNC, USFWS*

To be 

determined 1 1 1 1 1 

3 2.6.1 

Conduct surveys on Federal lands for Silene spaldingii. Ongoing BLM*, DOD, FS, USFWS 612 18 18 18 18 18 
132 

Implementation Schedule for the Silene spaldingii Recovery Plan 

Cost Estimates ($1,000) Priority 

Number 

Action 

Number 

Action Description Action 

Duration 

(years) 

Responsible 

Parties Total 

CostH

FY 

2007 

FY 

2008 

FY 

2009 

FY 

2010 

FY 

201

3 2.6.2 

Conduct surveys on State and Tribal lands, especially where activities may affect Silene spaldingii habitat. 

Ongoing HP, ST, T, USFWS 204 6 6 6 6 6 

3 2.6.3 

Obtain permission from private landowners to conduct surveys for Silene spaldingii

on private lands. 

Ongoing HP, NRCS, PVT*, USFWS 204 6 6 6 6 6 

3 2.7.1 

Support conservation actions on lands owned by The Nature Conservancy. 

Ongoing TNC*, USFWS

3 2.7.2 Support conservation activities on other private lands. Continual All 3 2.7.3 

Conduct outreach and awareness efforts with the public regarding Silene spaldingii's plight and its conservation. 

Continual All 272 8 8 8 8 8 

3 2.8 

Pursue land and species designations that will help facilitate conservation of Silene spaldingii. 

Continual All 34 1 1 1 1 1 

3 2.11 Validate and revise recovery objectives. Continual All, USFWS* 175 25 3 2.12 

Convene annual meetings of the Silene spaldingii technical team. 
133 

Implementation Schedule for the Silene spaldingii Recovery Plan 

Cost Estimates ($1,000) Priority 

Number 

Action 

Number 

Action Description Action 

Duration 

(years) 

Responsible 

Parties Total 

CostH

FY 

2007 

FY 

2008 

FY 

2009 

FY 

2010 

FY 

201

3 3.0 

Develop a post-delisting monitoring plan. 1 year All, USFWS* 10 

Total estimated cost for recovery 8,666 330 338 338 339 331
Recovery Plan for Silene spaldingii ● September 2007 

134 

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IN LITT. REFERENCES

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Button, Clair, 2004. Botanist, U.S. Bureau of Land Management, Baker City, 

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Button, Clair. 2005. Botanist, U. S. Bureau of Land Management, Baker City, 

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Caplow, Florence. 2003. Botanist, Washington Natural Heritage Program, 

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23 September 2003. 1 p. 

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Janice Engle, Fish and Wildlife Biologist, U.S. Fish and Wildlife Service, 

Boise, Idaho. Gravel pits and Silene spaldingii. 15 April 2004. 1 p. 

Gray, Karen. 2004. Botanist, Idaho Conservation Data Center, Moscow, Idaho. 

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Comments on the Silene spaldingii draft recovery strategy. 1 June 2004. 

3 pp.

Hays, Mike. 2007. Botanist, Nez Perce National Forest, Grangeville, Idaho. To 

Gina Glenne, Botanist, U.S. Fish and Wildlife Service, Boise, Idaho. 

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April 2007. 2 pp. 
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161 

Hill, Janice. 1999. Private consultant, Deary, Idaho. To Edna Rey-Vizgirdas, 

Botanist, U.S. Fish and Wildlife Service, Boise, Idaho. Silene spaldingii

at the Garden Creek Ranch. 6 January 1999. 4 pp. 

Hill, Janice. 2007a. Botanist, Idaho Conservation Data Center, Deary, Idaho. To 

Gina Glenne, Botanist, U.S. Fish and Wildlife Service, Boise, Idaho. 

Progress report on 5 year Silene spaldingii demography study in the 

Canyon Grasslands. 23 April 2007. 3 pp. 

Hill, Janice. 2007b. Botanist, Idaho Conservation Data Center, Deary, Idaho. To 

Gina Glenne, Botanist, U.S. Fish and Wildlife Service, Boise, Idaho. 

Comments of Recovery Plan. 23 April 2007. 12 pp. 

Holt, Jasa. 2006. Data Specialist, Washington Natural Heritage Program, 

Olympia, Washington. To: Gina Glenne, Botanist, U.S. Fish and Wildlife 

Service, Boise, Idaho. New separation distance for Washington Element 

Occurrences. 6 September 2006. 2 pp. 

Holt, Jasa. 2007. Data Specialist, Washington Natural Heritage Program, 

Olympia, Washington. To Gina Glenne, Botanist, U.S. Fish and Wildlife 

Service, Boise, Idaho. Extirpations in Washington. 4 April 2007. 10 pp. 

Hustafa, Jerold. 2004a. Botanist, U. S. Forest Service, Enterprise, Oregon. To 

Gina Glenne, Botanist, U. S. Fish and Wildlife Service, Boise, Idaho. 

Monitoring Silene spaldingii. 30 April 2004. 3 pp. 

Hustafa, Jerold. 2004b Botanist, U. S. Forest Service, Enterprise, Oregon. To 

Gina Glenne, U. S. Fish and Wildlife Service, Boise, Idaho. Weeds in 

Oregon found near Silene spaldingii populations. 30 April 2004. 3 pp. 

Johnson, Craig. 1997. Fisheries Biologist, U.S. Bureau of Land Management, 

Cottonwood Field Office, Idaho. Unauthorized Herbicide Spraying of 

Blackhawk Colony of MacFarlane’s Four-O’clock (Mirabilis 

macfarlanei). 27 June 1997. 6 pp. 
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162 

Lesica, Peter. 2003. Private consultant, Missoula, Montana. To Janice Hill, 

private consultant, Deary, Idaho. Comments on the draft conservation 

strategy for S. spaldingii. 17 November 2003. 6 pp. 

Lesica, Peter. 2004. Private consultant, Missoula, Montana. To Gina Glenne, 

Botanist, U.S. Fish and Wildlife Service, Boise, Idaho. Comments on the 

draft recovery strategy for Silene spaldingii. 1 June 2004. 7 pp. 

Lesica, Peter. 2006. Private consultant, Missoula, Montana. To: U.S. Fish and 

Wildlife Service, Boise, Idaho. Comments on Draft Recovery Plan for 

Silene spaldingii. 5 May 2006. 6 pp. 

Lesica, Peter. 2007a. Private consultant, Missoula, Montana. To: Gina Glenne, 

Botanist, U.S. Fish and Wildlife Service, Boise, Idaho. Comments on the 

last draft of the Silene spaldingii recovery plan. 23 April 2007. 3 pp. 

Lesica, Peter. 2007b. Private consultant, Missoula, Montana. To: U.S. Fish and 

Wildlife Service, Boise, Idaho. Litter accumulation at Dancing Prairie 

Preserve. 6 February 2007. 1 p. plus picture. 

Mantas, Maria. 2007. Western Montana Science and Stewardship Director, The 

Nature Conservancy, Coteau, Montana. To Gina Glenne, Botanist, U.S. 

Fish and Wildlife Service. 27 April 2007. 2 pp. 

Martin, Brian. 1998. Director of Science and Stewardship, The Nature 

Conservancy, Helena, Montana. To Edna Rey-Vizgirdas, Botanist, U.S. 

Fish and Wildlife Service, Boise, Idaho. Status of Spalding’s catchfly. 

Silene spaldingii. 4 December 1998. 1 p. 

Miles, Rebecca A. 2006. Nez Perce Tribal Executive Committee, Lapwai, Idaho. 

To: Jeff Foss, Field Supervisor, U.S. Fish and Wildlife Service, Boise, 

Idaho. Comments on the Draft Silene spaldingii Recovery Plan. 25 May 

2006. 8 pp. 

Morgan, Penny. 2007. Professor of Forest Resources, University of Idaho, 

Moscow, Idaho. To: Gina Glenne, Botanist, U.S. Fish and Wildlife 
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163 

Service, Boise, Idaho. Comments on fire frequencies in the Palouse and 

Canyon Grasslands. 10 February 2001. 4 pp. 

Raven, Andrea. 2004. Botanist, The Berry Botanic Garden, Portland, Oregon. 

To Gina Glenne, Botanist, U. S. Fish and Wildlife Service, Boise, Idaho. 

Collections of Silene spaldingii at the Berry Botanic Garden. 16 April 

2004. 10 pp. 

Taylor, Robert. 2003. Ecologist, The Nature Conservancy, Enterprise, Oregon. 

To Janice Hill, private consultant, Deary, Idaho. Questionnaire, Zumwalt 

Prairie and Clear Lake Ridge reports and maps. 4 April 2003. 10 pp. 

Taylor, Robert. 2004. Ecologist, The Nature Conservancy, Enterprise, Oregon. 

To Gina Glenne, Botanist, U. S. Fish and Wildlife Service, Boise, Idaho. 

Communication stating weed control is within 100 meters of Silene 

spaldingii populations. 28 April 2004. 1 p. 

U.S. Bureau of Land Management. 2006. Spokane District Office, Spokane 

Valley, Washington. Spalding’s catchfly comments. 11 May 2006. 9 pp. 

U.S. Fish and Wildlife Service. 2002. Formal Section 7 Consultation for the 

Bureau of Land Management’s Vale District Integrated Noxious Weed 

Management Program, 2001 to 2011. Biological Opinion transmitted in a 

memorandum from State Supervisor/Deputy State Supervisor, Oregon 

Fish and Wildlife Office, Portland, Oregon to District Manager, Vale 

District Bureau of Land Management, Vale, Oregon. Ref. no.1-7-F-01-

319. January 10, 2002. 

U.S. Fish and Wildlife Service. 2003. Bureau of Land Management Noxious 

Weed Control Program in the Snake, Salmon and Clearwater River 

Drainages, Idaho County, Idaho – Biological assessment and concurrence. 

Memorandum from Supervisor, U.S. Fish and Wildlife Service, Boise, 

Idaho to Field Manager, U.S. Bureau of Land Management, Cottonwood 

Field Office, Idaho. File #1005.2000 1-4-03-I-420. 3 April 2003. 15 pp. 
Recovery Plan for Silene spaldingii ● September 2007 

164 

Weddell, Bertie. 2003. Private consultant, Draba Consulting, Pullman, 

Washington. To Janice Hill, private consultant, Deary, Idaho. 

Questionnaire regarding Silene spaldingii. 27 June 2003. 7 pp. 

Wick, Arne. 2004. Fish and Wildlife Biologist, U.S. Fish and Wildlife Service, 

Kalispell, Montana. To Marilyn Hemker, Fish and Wildlife Biologist, U. 

S. Fish and Wildlife Service, Boise, Idaho. Occurrence of Silene 

spaldingii on Plum Creek lands is unknown. 15 April 2004. 1 p. 

Wood, Jean. 2004. Botanist, U.S. Forest Service, Pendleton, Oregon. To Gina 

Glenne, Botanist, U.S. Fish and Wildlife Service, Boise, Idaho. Silene 

spaldingii and weeds on the Umatilla National Forest. January 16, 2004. 

1 p. 

Yates, Gene. 2004. Botanist, U.S. Forest Service, Baker City, Oregon. To Gina 

Glenne, Botanist, U.S. Fish and Wildlife Service, Boise, Idaho. 

Comments on the draft recovery strategy. 28 May 2004. 1 p. 
Recovery Plan for Silene spaldingii ● September 2007 

165 

PERSONAL COMMUNICATIONS

Hustafa, Jerry. 1999. Botanist, U.S. Forest Service, Enterprise, Oregon. To Edna 

Rey-Vizgirdas, Botanist, U.S. Fish and Wildlife Service, Boise, Idaho. 

Silene spaldingii at Crow Creek, Oregon. 14 January 1999. 1 p. 

Kagan, Jimmy. 1998. Botanist, Oregon Natural Heritage Information Center, 

Portland, Oregon. Telephone conversation with Edna Rey-Vizgirdas, 

Botanist, U.S. Fish and Wildlife Service, Boise, Idaho. Information 

regarding noxious weeds and herbicide spraying. 22 December 1998. 1 p. 

Nitz, Timothy. 2004. Manager, U.S. National Park Service, Joseph, Oregon. 

Conversation with Gina Glenne, Botanist, U.S. Fish and Wildlife Service, 

Boise, Idaho. Silene spaldingii at the Chief Joseph National Historical 

Monument. 17 February 2004. 1 p. 

Raven, Andrea. 2004. Botanist, The Berry Botanic Garden, Portland, Oregon. 

To Gina Glenne, Botanist, U.S. Fish and Wildlife Service, Boise, Idaho. 

Tele-Fax with results of Silene spaldingii germination studies at the Berry 

Botanic Garden. 16 March 2004. 1 p. 

Riley, Scott. 1999. Botanist, U.S. National Forest, Pendleton, Oregon. To Edna 

Rey-Vizgirdas, Botanist, U.S. Fish and Wildlife Service, Boise, Idaho. 

Silene spaldingii on the Umatilla National Forest, Asotin County, 

Washington. 3 February 1999. 1 p. 

U.S. Fish and Wildlife Service. 2003. Meeting notes for the draft conservation 

strategy for Silene spaldingii in Lewiston, Idaho on October 28, 2003. 4 

November 2003. 7 pp. 

U.S. Fish and Wildlife Service. 2004. Notes from public meetings held in 

Montana , Idaho, Washington and Oregon February and March 2004. 9 

pp. 
Recovery Plan for Silene spaldingii ● September 2007 

166 

White, Jim. 2003. Manager, Idaho Department of Fish and Game, Lewiston, 

Idaho. Conversation with Gina Glenne, Botanist, U.S. Fish and Wildlife 

Service, Boise, Idaho. Silene spaldingii on Idaho Fish and Game, Craig 

Mountain Wildlife Management.
Recovery Plan for Silene spaldingii ● September 2007 

A-1 

Appendix A. Endangered and Threatened Species Recovery Priority 

Number Guidelines*

Degree of Threat Recovery 

Potential Taxonomy Conflict?† Priority

Monotypic Genus Yes 1C 

No 1 

Species Yes 2C 

No 2 

Yes 3C 

High 

Subspecies 

No 3 

Monotypic Genus Yes 4C 

No 4 

Species Yes 5C 

No 5 

Yes 6C 

High 

Low 

Subspecies 

No 6 

Monotypic Genus Yes 7C 

No 7 

Species Yes 8C 

No 8 

Yes 9C 

High 

Subspecies 

No 9 

Monotypic Genus Yes 10C 

No 10 

Species Yes 11C 

No 11 

Yes 12C 

Moderate 

Low 

Subspecies 

No 12 

Monotypic Genus Yes 13C 

No 13 

Species Yes 14C 

No 14 

Yes 15C 

High 

Subspecies 

No 15 

Monotypic Genus Yes 16C 

No 16 

Species Yes 17C 

No 17 

Yes 18C 

Low 

Low 

Subspecies 

No 18 

* adapted from Listing and Recovery Priority Guidelines, Federal Register 48:4309-43105 

†priority is given to those species that are, or may be, in conflict with construction or other development 

projects or other forms of economic activity, designated by a “C” in the priority ranking system.
Recovery Plan for Silene spaldingii ● September 2007 

B-1 

Appendix B. Scientific and common names used in the text.

Plants 

Scientific name Common name 

Acroptilon repens (L.) DC. Russian knapweed 

Agropyron cristatum (L.) Gaertn. crested wheatgrass 

Agropyron desertorum (Fisch. ex 

Link) J.A. Schultes crested wheatgrass 

Amsinckia grandiflora (Kleeb. Ex 

Gray) Kleeb. Ex Greene large-flowered fiddleneck 

Arabis fecunda Rollins Mt. Sapphire rockcress 

Artemisia tridentata Nutt. big sagebrush 

Artemisia tripartita Rydb. three-tip sagebrush 

Anthriscus caucalis Bieb. bur chervil 

Aster jessicae Piper =

Symphyotrichium jessicae (Piper) 

Nesom 

Jessica’s aster 

Astragalus riparius Barneby Piper’s milk-vetch 

Bromus inermis Leyss. smooth brome 

Bromus japonicus Thunb. ex Murr = 

B. arvensis L. Japanese brome 

Bromus tectorum L. cheatgrass 

Calochortus macrocarpus Dougl. var. 

maculosus A. Nels and J.F. Macbr. green-band or Nez Perce mariposa lily 

Calochortus nitidus Dougl. broad-fruit mariposa 

Cardaria draba (L.) Desv. whitetop 

Centaurea diffusa Lam. diffuse knapweed 

Centaurea maculosa = C. stoebe L. 

ssp. micranthos (Gugler) Hayek spotted knapweed 

Centaurea solstitialis L. yellow starthistle 

Chondrilla juncea L. rush skeletonweed 

Cirsium arvense (L.) Scop. Canada thistle 

Cirsium brevifolium Nutt. Palouse thistle 

Cirsium vinaceum Woot. & Standl. Sacramento Mountains thistle 

Crupina vulgaris Cass. common crupina 

Dianthus deltoides L. maiden pink 

Dipsacus sylvestris Huds. = Dipsacus teasel 
Recovery Plan for Silene spaldingii ● September 2007 

B-2 

Scientific name Common name 

fullonum L. 

Euphorbia esula L. leafy spurge 

Festuca idahoensis Elmer Idaho fescue 

Festuca scabrella Torr. ex Hook = F. 

campestris Rydb. rough fescue 

Hesperostipa comata (Trin. & Rupr) 

Barkworth = Stipa comata Trin. & 

Rupr. 

needle-and-thread grass 

Hieracium pratense Taush = H. 

caespitosum Dumort. meadow hawkweed 

Hypericum perforatum L. St. Johnswort 

Koeleria cristata Pers. = K. macrantha 

(Ledeb.) J.A. Schultes prairie junegrass 

Lepidium latifolium L. perennial pepperweed 

Linaria dalmatica (L.) P. Mill Dalmatian toadflax 

Linaria spp. toadflax 

Lupinus sericeus Pursh. silky lupine 

Mirabilis macfarlanei Constance & 

Rollins Macfarlane’s four-o’clock 

Onopordum acanthium L. Scotch thistle 

Pinus ponderosa P. & C. Lawson ponderosa pine 

Poa pratensis L. Kentucky bluegrass 

Polemonium pectinatum Greene Washington polemonium 

Potentilla recta L. sulfur cinquefoil 

Primula elatior (L.) Hill oxlip 

Pseudoroegneria spicata (Pursh) A. 

Löve = Agropyron spicatum Pursh bluebunch wheatgrass 

Pyrrocoma liatriformis Greene = 

Happlopappus liatriformis (Greene) 

St. John

Palouse goldenweed 

Rosa spp. rose 

Rubus nigerrimus (Greene) Rydb. Northwest raspberry 

Scabiosa columbaria L. dove pincushions, pincushion flower 

Silene cserei Baumg. Balkan catchfly 

Silene douglasii Hook. Douglas’ catchfly 

Silene hawaiiensis Sherff Hawai`i catchfly 
Recovery Plan for Silene spaldingii ● September 2007 

B-3 

Scientific name Common name 

Silene latifolia Poir ssp. alba (P. Mill) 

Greuter & Burdet bladder campion 

Silene oregana S. Wats. Oregon catchfly 

Silene regia Sims royal catchfly 

Silene scaposa B.L. Robins var. 

scaposa Scapose silene 

Silene scouleri Hook. Scouler’s catchfly 

Silene spaldingii S. Wats. Spalding’s catchfly, Spalding’s silene, 

Spalding’s campion 

Symphoricarpos albus (L.) Blake snowberry 

Trifolium plumosum Dougl. ex. Hook. 

var. amplifolium (J.S. Martin) J. Gillett plumed clover 

Ventenata dubia (Leers) Coss. ventenata 

Animals 

Scientific Name Common Name or Type of Animal 

Bombus fervidus (Fabricius) bumblebee 

Bombus terrestris (L.) bumblebee 

Lasioglossum spp. solitary bee 

Halictus tripartitus Cockerell solitary bee 

Dienoplus rugulosus R. Bohart solitary bee 

Apis spp. honey bee 

Tympanuchus phasianellus 

columbianus Ord 

Columbian sharp-tailed grouse 
Recovery Plan for Silene spaldingii ● September 2007 

C-1 

Appendix C. Summary of Threats and Recommended Recovery Actions 

for Silene spaldingii 

This table identifies the recovery actions recommended to address the 

threats to Silene spaldingii, as well as those recovery criteria that will provide a 

measure of the elimination or sufficient reduction of those threats to consider 

delisting of this threatened species. 

Listing 

Factor* Threat 

Recovery 

Criteria Recovery Action Numbers 

A 

Invasive 

Nonnative 

Plants 

2, 3, 4, 5 

1. conserve and expand populations 

in each physiographic region; 1.1.3. 

control in Blue Mountain Basins; 

1.2.3. control in Canyon Grasslands; 

1.3.2. control in the Channeled 

Scablands; 1.4.3. control in the 

Intermontane Valleys; 1.5.4. control 

in the Palouse Grasslands; 2.1 general 

management plans; 2.3 habitat 

management plans; 2.3.1 invasive 

nonnative plant control; 2.4 monitor; 

2.5.3 control research; 2.7 private 

land conservation; 2.10 funding 

A, E 

Problems 

Associated with 

Small, 

Geographically 

Isolated 

Populations 

1, 2, 3, 4, 

7 

1. conserve and expand populations 

in each physiographic region; 2.1 

general management plans; 2.3 

habitat management plans; 2.4 

monitor; 2.5.1 population viabilities; 

2.5.2 develop larger populations; 

2.5.6 reproductive biology research; 

2.5.7 seed dispersal research; 2.5.8 

seed viability research; 2.5.9 genetic 

research 2.7 private land 

conservation; 2.9 propagule banks, 

2.10 funding 
Recovery Plan for Silene spaldingii ● September 2007 

C-2 

Listing 

Factor* Threat 

Recovery 

Criteria Recovery Action Numbers 

A 

Changes in the 

Fire Regime 

and Fire Effects 

2, 3, 4, 6 

1. conserve and expand populations 

in each physiographic region; 2.1 

general management plans; 2.3 

habitat management plans; 2.3.2 fire 

management; 2.5.5 fire research 

A 

Land 

Conversion 

Associated with 

Urban and 

Agricultural 

Development 

1, 2, 3, 4 

1. conserve and expand populations 

in each physiographic region; 2.1 

general management plans; 2.3 

habitat management plans; 2.3.3 

protect from development; 2.4 

monitor; 2.6 surveys; 2.7 private land 

conservation; 2.10 funding 

A, C 

Adverse 

Livestock 

Grazing and 

Trampling 

2, 3, 4 

1. conserve and expand populations 

in each physiographic region; 2.1 

general management plans; 2.3 

habitat management plans; 2.3.4 

manage livestock grazing; 2.4 

monitor; 2.5.4 research; 2.7 private 

land conservation; 2.10 funding 

E 

Herbicide and 

Insecticide 

Spraying 

2, 3, 4 

1. conserve and expand populations 

in each physiographic region; 2.1 

general management plans; 2.3 

habitat management plans; 2.3.1.6 

herbicide application guidelines; 2.4 

monitor; 2.5.3 control research; 2.7 

private land conservation; 2.10 

funding 

C 

Adverse 

Grazing 

(Herbivory) and 

Trampling by 

Wildlife 

Species 

2, 3, 4 

1. conserve and expand populations 

in each physiographic region; 2.1 

general management plans; 2.3 

habitat management plans; 2.3.6 

monitor and manage wildlife; 2.4 

monitor; 2.5.4 research; 2.7 private 

land conservation; 2.10 funding 
Recovery Plan for Silene spaldingii ● September 2007 

C-3 

Listing 

Factor* Threat 

Recovery 

Criteria Recovery Action Numbers 

A, E Off-Road 

Vehicle Use 2, 3, 4 

1. conserve and expand populations 

in each physiographic region; 2.1 

general management plans; 2.3 

habitat management plans; 2.3.5 

implement off-road vehicle control; 

2.4 monitor; 2.7 private land 

conservation; 2.10 funding 

C Insect Damage 

and Disease 2, 3, 4 

1. conserve and expand populations 

in each physiographic region; 2.1 

general management plans; 2.3 

habitat management plans; 2.4 

monitor; 2.5.4 research; 2.10 funding 

E 

Impacts from 

Prolonged 

Drought and 

Global 

Warming 

2, 3, 4 

1. conserve and expand populations 

in each physiographic region; 2.1 

general management plans; 2.3 

habitat management plans; 2.4 

monitor; 2.10 funding 

D 

Inadequacy of 

Existing 

Regulatory 

Mechanisms 

2, 3, 4 

1 conserve and expand populations in 

each physiographic region; 2.1 

general management plans; 2.3 

habitat management plans; 2.4 

monitor; 2.7 private land 

conservation; 2.8 pursue land and 

species designations, 2.10 funding 

*Listing Factors: 

A. The Present or Threatened Destruction, Modification, of Curtailment of 

Silene spaldingii’s Habitat or Range 

B. Overutilization for Commercial, Recreational, Scientific, or Educational 

Purposes 

C. Disease or Predation 

D. The Inadequacy of Existing Regulatory Mechanisms 

E. Other Natural or Manmade Factors Affecting Silene spaldingii’s 

Continued Existence.
Recovery Plan for Silene spaldingii ● September 2007 

D-1 

Appendix D. Summary of Public, Agency, and Peer Review Comments 

on the Draft Recovery Plan for Silene spaldingii (Spalding’s 

Catchfly) 

On October 10, 2001, we, the U.S. Fish and Wildlife Service, listed Silene 

spaldingii (Spalding’s catchfly) as a threatened species, under the Endangered 

Species Act of 1973, as amended. On December 17, 2001, a recovery outline was 

prepared. We then contracted the Idaho Conservation Data Center to compile a 

Conservation Strategy for Spalding’s catchfly (Silene spaldingii Wats.)

(Conservation Strategy). In writing the Conservation Strategy, over 35 

individuals were consulted from the private sector, educational facilities, 

government agencies, and land managing conservation organizations. A group 

was assembled in Lewiston, Idaho on October 28, 2003, to discuss the draft 

Conservation Strategy, recovery priorities, and the next steps in the recovery 

planning process. The Conservation Strategy was complete on February 23, 2004 

(Hill and Gray 2004a). This Conservation Strategy was utilized extensively in 

writing the Draft Recovery Plan for Silene spaldingii (Spalding’s catchfly). 

In addition, eight meetings were held to allow stakeholders to learn about 

and contribute to the recovery planning effort in early 2004, two meetings at each 

of four locations (Kalispell, Montana, on February 26th; Enterprise, Oregon, on 

March 1st; Ritzville, Washington, on March 2nd; and Lewiston, Idaho, on March 

3rd). We also identified over 12 individuals to participate in a technical team. 

Members of this technical team reviewed and provided input on early versions of 

the draft recovery plan and participated in a related conference call on June 1, 

2004. 

The Draft Recovery Plan for Silene spaldingii (Spalding’s catchfly) was 

made available to the public through a 60-day comment period from March 16, 

2006, to May 15, 2006. More than 600 letters were sent out to individuals 

notifying them of the availability of the draft recovery plan. Over 50 copies of the 

draft recovery plan were sent out and electronic copies were available on our web 

site for review during the comment period. Additionally, letters were sent to 

Federal, State, Tribal, and local government offices within the range of the 

species as well as industry groups, conservation groups, scientists and interested 

parties. Members of the technical team provided comments during the 60-day 

comment period, reviewed a draft of the final recovery plan, and participated in a 
Recovery Plan for Silene spaldingii ● September 2007 

D-2 

conference call on April 30, 2007. A list of individuals we solicited technical 

comments from is included in Appendix E. 

Ten responses were received during the public comment period from the 

public and various agencies including: Idaho Conservation League; Idaho 

Department of Lands; Montana Fish, Wildlife and Parks; U.S. Bureau of Land 

Management Montana State Office, U.S. Department of Agriculture Pullman 

Plant Material Center; State of Idaho’s Department of Agriculture, Idaho Office 

of Species Conservation, Friends of the Clearwater, and the general public. 

We also received five peer review comments from: Peter Lesica; Scott 

Mincemoyer, Montana Natural Heritage Program; Maria Manta, The Nature 

Conservancy of Montana; Angela Sondenaa representing the Nez Perce Tribal 

Executive Committee; and Barbara Benner representing the U.S. Bureau of Land 

Management Spokane District Office. 

Number of letters received by affiliation: 

Federal agencies 2 letters 

State and local governments 4 letters 

Environmental interest 2 letter 

General public 2 letters 

Peer review 5 letters 

We also requested a review of the draft final recovery plan from 10 

scientists and agency persons familiar with Silene spaldingii and that had

participated in the S. spaldingii technical team. This final technical review was to 

ensure that revisions to the draft recovery plan based on public, agency, and peer 

review were scientifically sound. These individuals included: LeAnn Abell, U.S. 

Bureau of Land Management, Idaho; Barbara Benner, U.S. Bureau of Land 

Management, Washington; John Gamon, Washington Natural Heritage Program; 

Karen Gray, Idaho Conservation Data Center; Mike Hays, Nez Perce National 

Forest; Dr. Janice Hill, Idaho Conservation Data Center; Peter Lesica, private 

consultant; Mark Lowry, U.S. Bureau of Land Management, Idaho; Maria 

Mantas, The Nature Conservancy of Montana; and Jim White, Idaho Department 

of Fish and Game. 
Recovery Plan for Silene spaldingii ● September 2007 

D-3 

Summary of significant issues and comments: 

We received 10 public/agency and 5 peer review responses during the 

public comment period for the draft recovery plan. Some comments provided 

updated information about Silene spaldingii and its habitat. This information was 

incorporated into the appropriate sections of the final recovery plan. The 

substantive issues and comments, and our responses, are summarized in this 

appendix. 

Issue 1: Several commenters questioned the definition of key conservation areas 

and their applicability in the recovery plan. Several commenters questioned the 

number of populations and the number of populations within physiographic 

regions in the recovery plan. Several commenters questioned the criteria in the 

recovery plan of 500 plants per population. One commenter suggested that key 

conservation areas be composed of at least 40 acres of habitat and surrounded by 

at least 300 acres of habitat that can be restored and eventually support Silene 

spaldingii. One commenter suggested that key conservation areas be spread 

across each physiographic region. One commenter questioned how populations 

of 500 would be an acceptable number for populations that already have over 500 

plants. 

Response: This recovery plan emphasizes conservation efforts for larger 

populations of Silene spaldingii while attempting to preserve the genetic diversity 

within each of the five physiographic regions where the plant resides. This is in 

line with the conservation strategy suggested by Nunney and Campbell (1993, pp. 

235-238), which focuses on the preservation of several populations, each 

supporting a density of at least the minimum viable population size, across 

heterogeneous habitats. We agree that a population viability analysis would assist 

us in better identifying a minimum number of individuals of Silene spaldingii. 

However, in the absence of a population viability analysis, and based on 

recommendations from species experts, we utilize the standard minimum of 250 

to 500 reproductive individuals (summarized in Schonewald-Cox et al. 1983, p. 

392) and suggest that this number be revisited by species experts when a 

population viability analysis is completed. Sites with more than 500 plants will 

be maintained at or above current population numbers. Recovery Criterion 3 

specifically states that populations will have stable or increasing trends. 
Recovery Plan for Silene spaldingii ● September 2007 

D-4 

We have made adjustments to the number of key conservation areas and 

their distribution across physiographic regions to incorporate commenters’ 

suggestions. We set a minimum of three key conservation areas per 

physiographic region, and higher numbers of key conservation areas where it is 

believed that suitable habitat either exists or potentially can exist, to reach the 

total number of 27 key conservation areas across the historical range of Silene 

spaldingii. This number is intended to preserve the available genetic variability 

within the species and provide for its long-term persistence. We have added 

additional text in the recovery plan that states, when possible, key conservation 

areas should be surrounded by 300 acres of habitat that is intact or can be restored 

to eventually support S. spaldingii. We also added language that key conservation 

areas should be spread across each physiographic region. 

Issue 2: Several commenters suggested that the plan must rely on a population 

viability analysis and that the plan should be adaptive to incorporate results from 

such an analysis. One commenter questioned who would lead recovery efforts, 

and make assessments that recovery criteria are being met. Several commenters 

questioned who would be responsible for various actions and how cooperation 

should occur. 

Response: We agree that a population viability analysis would be useful for 

better managing Silene spaldingii and as a useful tool for assessing the validity of 

preserving the species based on populations composed of at least 500 reproducing 

individuals. However, minimum viable population size estimates are often 

erroneous as they relate to extinction risk (Brook et al. 2006, p. 375). We are 

required under section 4(f)(1)(B)(ii) of the Endangered Species Act of 1973 as 

amended, to have objective, measurable criteria. We have written Recovery 

Criterion 1 to meet this statute and included a population viability analysis as a 

recovery action. We have identified agencies responsible, including the primary 

agency responsible, for each action in the recovery plan in the Implementation 

Schedule. The Service is the primary agency responsible for assessing if recovery 

criteria are being met as well as for revising recovery criteria. We have added 

recovery action 2.12 (Convene annual meetings of the Silene spaldingii technical 

team) to the recovery plan and identified this team to guide all recovery efforts. 

The action states: Annual meetings or conference calls of the Silene spaldingii 

technical team should be conducted. The technical team should be composed of 

interested individuals and organizations. These annual meetings should inform 
Recovery Plan for Silene spaldingii ● September 2007 

D-5 

other members of ongoing S. spaldingii conservation actions, and serve as a 

forum to discuss, coordinate, and prioritize recovery actions. We anticipate the 

technical team, when the population viability analysis is completed, will evaluate 

if the criterion of at least 500 reproducing Silene spaldingii individuals should be 

adjusted in the future.

Issue 3: One commenter suggested that the recovery plan should discuss the 

possibility of de-listing populations by physiographic region. 

Response: Until recently, plants were not listed or de-listed except as a whole 

taxonomic entity (species or subspecies). That is, distinct population segments 

only applied to species of vertebrate fish or wildlife. However, recent draft 

guidance (D. Bernhardt, in litt. 2007), relating to the meaning of the phrase “in 

danger of extinction throughout all or a significant portion of its range” in the 

Endangered Species Act, may make it possible to list and de-list portions of 

species range based on various boundaries, which could include physiographic 

region.

Issue 4: One commenter suggested that smaller occurrences be given more 

weight in the recovery plan. 

Response: As mentioned before, this recovery plan emphasizes conservation 

efforts for larger populations of Silene spaldingii while attempting to preserve the 

genetic diversity within each of the five physiographic regions where the plant 

resides. This is in line with the conservation strategy suggested by Nunney and 

Campbell (1993, pp. 235-238), which focuses on the preservation of several 

populations, each supporting a density of at least the minimum viable population 

size, across heterogeneous habitats. Furthermore, it is difficult to craft recovery 

criteria for small populations and these small populations, given their limited size, 

may not add much benefit to the overall recovery of the species. 

With that in mind, we have addressed conservation of smaller populations. 

For example, Recovery Criterion 7 states: “Seed banking occurs ex situ for all 

smaller Silene spaldingii populations (not key conservation areas or potential key 

conservation areas) to preserve the breadth of genetic material across the species’ 

range”. We have added recovery actions 1.1.3, 1.2.3, 1.3.3, 1.4.3, and 1.5.4 to 

conserve and protect smaller populations within each physiographic region. We 
Recovery Plan for Silene spaldingii ● September 2007 

D-6 

also modified action 2.3 to include both potential key conservation areas as well 

as smaller populations.

Issue 5: One commenter questioned how recovery actions in the recovery plan 

were prioritized. 

Response: The Service’s policy on how recovery actions are prioritized within 

recovery plans dictates priorities numbers. The Service’s definition of recovery 

action priorities are as follows: Priority 1 – An action that must be taken to 

prevent extinction or to prevent the species from declining irreversibly in the 

foreseeable future; Priority 2 – An action that must be taken to prevent a 

significant decline in species population or habitat quality, or some other 

significant negative impact short of extinction; Priority 3 – All other actions 

necessary to meet the recovery objectives. Within each of these priority rankings, 

actions are not further prioritized. For example, while a population viability 

analysis is very important for better recovery planning, it is not an action that 

must be taken to prevent extinction of the species. We have added recovery 

action 2.12 (Convene annual meetings of the Silene spaldingii technical team) to 

assist managers and landowners in further prioritizing recovery actions. We also 

revised the priority number of several recovery actions based on commenters 

suggestions. 

Issue 6: Several commenters suggested that the recovery plan did not adequately 

address the role of private lands in recovery. One commenter suggested that 

populations on public lands were not given enough special consideration. Several 

commenters suggested additional mechanisms for collaboration and protecting 

populations on private lands. One commenter suggested one recovery goal should 

be to engage with non-Federal partners to implement strategies, and that 

cooperation and mechanisms necessary for partnerships are vague or not 

discussed. 

Response: Of the already identified 22 potential key conservation areas, 6 are 

solely on federally managed lands, 4 are on lands with both Federal management 

and private ownership, 1 has Federal, private, and The Nature Conservancy 

management or ownership, 4 have lands under both Federal and State 

management, 1 is on lands solely managed by States, 1 is on land managed solely 

by The Nature Conservancy, 1 is on land managed both by The Nature 
Recovery Plan for Silene spaldingii ● September 2007 

D-7 

Conservancy and under private ownership, 2 are solely on Tribal lands, and 2 are 

solely on privately owned lands (see Table D-1 below). 

Table D-1. Ownership of potential key conservation areas. 

Potential Key Conservation 

Area Ownership 

Clear Lake Ridge The Nature Conservancy (TNC)/ WallowaWhitman National Forest (WWNF)/private 

Crow Creek WWNF/private 

Wallowa Lake Private/Old Chief Joseph Gravesite 

(managed by the National Park Service) 

Zumwalt Prairie The Nature Conservancy (TNC) 

Blue Mountain Foothills Umatilla National Forest 

Center Ridge Nez Perce National Forest 

Craig Mountain Idaho Department of Fish and Game/ 

Cottonwood District Bureau of Land 

Management (CBLM) 

Garden Greek TNC/CBLM 

Joseph Creek Nez Perce Tribe 

Coal Creek – Lamona Spokane District Bureau of Land 

Management (SBLM) 

Crab Creek SBLM 

Fishtrap Lake – Miller Ranch SBLM/private 

Rocky Ford SBLM 

Swanson Lake SBLM/Washington Department of Fish and 

Wildlife 

Telford SBLM 

Twin Lakes SBLM/private 

Crosson Valley Confederated Salish and Kootenai Tribes 

Dancing Prairie The Nature Conservancy 

Lost Trail Lost Trail National Wildlife 

Refuge/Montana State Trust Lands 

Kramer Palouse Natural Area Washington State University 

Paradise Ridge/Gormsen Butte Private 

Pitt Cemetery Private 
Recovery Plan for Silene spaldingii ● September 2007 

D-8 

Clearly the participation of Federal, State, Tribal, The Nature 

Conservancy, and private entities is needed for the recovery of Silene spaldingii. 

Conservation of S. spaldingii on private lands is dependent on willing 

landowners, and cooperation with Federal and State agencies for funding. We 

have further identified mechanisms for cooperation and funding on private lands 

with the recovery actions and implementation schedule in recovery action 2.7 

(Support conservation on privately owned lands). We have also added action 2.12 

(Convene annual meetings of the S. spaldingii technical team) to guide recovery 

actions that are needed for conservation on private lands. Conservation on private 

lands that may serve as potential key conservation areas is included in the 

recovery criteria. 

Issue 7: Several commenters suggested that the recovery plan did not identify all 

known or potential population sites. Several commenters suggested that the 

recovery plan did not identify additional areas to be surveyed nor did it prioritize 

areas to survey based on physiographic areas. On commenter suggested that 

surveys on Federal land be a high priority since protecting sites on Federal land is 

less expensive than restoring known or establishing new Silene spaldingii sites. 

Response: We have used the best available scientific information in the final 

recovery plan. The population information is current as of May 2007. 

Habitat models have been used to predict where Silene spaldingii occurs 

in several instances. However, these models have all resulted in large tracts of 

suitable habitat that are too big to easily survey, making further prioritization of 

these areas difficult. Better techniques are need to further refine and prioritize 

surveys. The following areas are listed in the text: Because the Canyon 

Grasslands are extremely steep and quite remote, there are still significant 

portions of suitable habitat to be searched, particularly on the Oregon side of the 

Snake River directly across from Craig Mountain, along the lower Grande Ronde 

River in Oregon and Washington, the Imnaha River in Oregon, and the lower 

Clearwater and Salmon Rivers in Idaho (please see Hill and Gray 2004a, pp. 17-

21 for a summary of areas to be surveyed). Over 40 percent of known S. 

spaldingii sites are on private land; in general, these private lands have had much 

less inventory effort. The possibility for large populations residing on private 

property can not be overlooked. Several recent Bureau of Land Management land 

acquisitions in Washington (B. Benner, in litt. 2003, p. 3), as well as The Nature 
Recovery Plan for Silene spaldingii ● September 2007 

D-9 

Conservancy’s acquisition in 2000 of the Zumwalt Prairie Preserve, have led to 

the discovery of large, previously unknown S. spaldingii populations. Federal 

lands, because of environmental regulations, are already inventoried more 

frequently than State or private lands. 

Issue 8: One commenter suggested that standardized monitoring methodologies 

are needed across the range of the species. Another commenter suggested that 

demographic monitoring needs to occur in early June as well as later in the season 

to capture early season rosettes and later season reproductive structure 

information. 

Response: We have included language under all 2.4 (Monitor population trends 

and habitat conditions) recovery action items relating to a standardized 

monitoring procedure as follows: “In as much as possible, a standardized trend 

monitoring procedure should be established rangewide. This will be challenging 

because different areas may require different protocols.” We have added recovery 

action 2.12 (Convene annual meetings of the Silene spaldingii technical team). 

Already efforts are underway to develop standardized monitoring methodologies 

through the technical team. We have added language to recovery action 2.4.2

(Conduct demographic monitoring across the range of Silene spaldingii) to 

address the need to conduct demographic monitoring twice a year, and for a 

minimum of 10 years. 

Issue 9: One commenter suggested suitable techniques for supplementing or 

creating new Silene spaldingii populations. Several commenters supported plans 

to create new populations, especially in the Palouse Prairie. Several commenters 

suggested that guidelines be developed to ensure genetic conservation during 

supplementation, re-introduction, and introduction activities. 

Response: We have added recovery action 2.5.2.2 (Develop guidelines to ensure 

genetic conservation during supplementation, re-introduction, and introduction 

activities) to the Recovery Plan. Re-introduction to create new populations are 

suggested for several physiographic regions. 

Issue 10: Several commenters questioned the recovery criteria in the recovery 

plan associated with controlling/eradicating invasive nonnative plant species. 

Several commenters stated that the 0.4 kilometer (0.25 mile) radius for invasive 
Recovery Plan for Silene spaldingii ● September 2007 

D-10 

nonnative plant control was not feasible or economical. One commenter 

suggested that keeping invasive nonnative plant species below 20 percent would 

not be as effective as eliminating them within a smaller perimeter. One 

commenter questioned if there was any evidence that exotic annual grasses have 

negatively affected the species. Several commenters discussed integrated pest 

management strategies; one commenter stated that integrated pest management 

strategies rely on reducing the frequency and density of invasive nonnative plant 

species rather than eradicating them. Several commenters suggested that 

herbicides should be used to control the spread of non-native species while one 

commenter suggested that herbicides should not be used in, or adjacent to known 

habitat. One commenter suggested that herbicides with short residual effects be 

used near Silene spaldingii. 

Response: Based on recommendations, we adjusted the 0.4 kilometer (0.25 mile) 

radius for control of invasive nonnative plant to 100 meters (328 feet), and for 

those invasive nonnative plant species that are already more common from 80 

percent cover to control within a 50 meter (164 foot) radius (see actions 1.1.4, 

1.2.4, 1.3.4, 1.4.4, 1.5.5). We have no specific evidence that exotic annual 

grasses have negatively affected the species, but assume the possibility. 

We have added more information for integrated pest management 

techniques and clarified that these techniques strive to use the least aggressive 

tool necessary and added two pertinent review citations. Integrated pest 

management strategies utilize the least aggressive tool necessary to achieve 

management goals and utilize all control methods available such as prevention, 

manual control, biological control, and herbicide control. In some instances, the 

use of herbicides may be necessary to effectively control an invasive nonnative 

plant infestation. For example, a particular invasive nonnative plant may have 

deep underground roots that are impossible to remove by hand pulling. Having an 

integrated pest management plan in place will help identify when and where 

herbicides may be necessary, and what herbicides would control the invasive 

nonnative plant while causing the least harm to Silene spaldingii, its pollinators,

and its habitat. We have used the word “control” rather than “eradicate,” 

recognizing that eradication may be extremely difficult. We have added recovery 

action 2.3.7 (Avoid herbicide use not related to controlling invasive nonnative 

plant infestations specific to protecting S. spaldingii and all insecticide use within 
Recovery Plan for Silene spaldingii ● September 2007 

D-11 

a 1.6 kilometer (1 mile) radius of all S. spaldingii populations) to protect 

pollinators. 

Issue 11: One commenter stated that the recovery plan did not allow the use of 

nonnative grasses for restoring sites that are near or contain Silene spaldingii. 

Response: There is considerable discussion on how best to restore degraded sites 

within the arid west (Lesica and Allendorf 1999, Jones 2003, Roundy 2005). We 

recognize that native species may be more difficult to obtain and costly, and that 

successful invasive nonnative plant control and restoration with native species can 

be more difficult on arid sites or sites adjacent to invasive nonnative sites 

(Roundy 2005, p. 48). The use of nonnative restoration species and competition 

with rare species is not well understood. However, there are examples of 

nonnative restoration species affecting other rare plant species. For these reasons, 

we continue to suggest that nonnative restoration species should not be used near 

Silene spaldingii sites, unless previous greenhouse studies have shown that the 

nonnative restoration species will not compete with S. spaldingii. 

Issue 12: Several commenter suggested that prescribed fire should be used to 

control vegetation and promote Silene spaldingii recruitment while one 

commenter suggested that prescribed fire should not be used in or adjacent to 

known habitat. Several commenters suggested that prescribed fire should be a 

tool that can be utilized when invasive nonnative species are present so long as 

integrated pest management practices are in place. 

Response: We continue to include prescribed burning as a potential tool to be 

used cautiously, but have added language making it possible to do so in the 

presence of invasive nonnative plant infestations with appropriate invasive 

nonnative plant control measures, monitoring, and a management strategy being 

in place prior to the prescribed burn. We also added language recommending that 

only portions of Silene spaldingii populations be burned at any one time. 

Issue 13: Several commenters stated that we do not understand the effects of 

livestock grazing and trampling on Silene spaldingii. Several commenters noted 

the recovery plan identified that managed livestock grazing could be beneficial to, 

or compatible with S. spaldingii. One commenter stated that managed livestock 

grazing should be considered an option when prescribed fire is not feasible to 
Recovery Plan for Silene spaldingii ● September 2007 

D-12 

control litter accumulation and promote S. spaldingii recruitment. Other 

commenters stated that any level of livestock grazing and trampling is detrimental 

to the species, or provides a neutral effect depending how areas are managed. 

Several commenters stated that livestock grazing and trampling leads to habitat 

degradation. Several commenters stated that some recovery actions in the 

recovery plan related to livestock grazing appear to be unrealistic, for example, 

the time period when livestock use should not occur. One commenter stated we 

had not utilized livestock grazing references appropriately. One commenter 

stated that eliminating livestock grazing and trampling from S. spaldingii 

populations could limit the opportunity for future land acquisitions that would 

benefit S. spaldingii. 

Response: Livestock grazing and trampling is probably the most contentious 

management issue within the range of Silene spaldingii with critics and supporters 

(see Curtin 2002, p. 240). Sufficient research has not been completed to 

determine what effects livestock grazing is having on S. spaldingii. We modified 

our suggestions in recovery action 2.3.4 to state that livestock grazing may occur 

with careful monitoring. It is recommended that monitoring associated with 

livestock use include paired grazed versus ungrazed transects at each site where 

grazing occurs to adequately determine whether grazing is having an effect. In 

addition, the vegetation community should be assessed at each paired plot to 

determine the effects livestock may be having on the habitat. 

We have modified our “Adverse Livestock Grazing and Trampling” 

section in the document to incorporate commenters suggestions. 

Issue 14: One commenter suggested that cumulative impacts of herbivory from 

native and non-native ungulates, rodents, and insects should be assessed. 

Response: We have added to both recovery actions 2.3.4 (Monitor and manage 

livestock grazing and associated management activities to avoid impacts to Silene 

spaldingii and its habitat) and 2.3.6. (Monitor and manage wildlife populations 

and associated management activities to avoid impacts to S. spaldingii and its 

habitat) that cumulative effects of herbivory should be assessed in areas where 

both native and domestic ungulates graze. 
Recovery Plan for Silene spaldingii ● September 2007 

D-13 

Issue 15: Several commenters suggested that invasive nonnative plant species 

spread along roads. 

Response: We have included a discussion of roads and how invasive nonnative 

species move along them under the threat “Land Conversion Associated with 

Urban and Agricultural Development.”
Recovery Plan for Silene spaldingii ● September 2007 

E-1 

Appendix E. List of agencies and individuals we requested to provide 

comments for the Silene spaldingii Recovery Plan. 

LeAnn (Eno) Abell and Mark Lowry, U.S. Bureau of Land Management, Idaho

Joseph Arnett, Florence Caplow, and John Gamon, Washington Natural 

Heritage Program 

Barbara Benner and Diane Stutzman, U.S. Bureau of Land Management, 

Washington 

Joanne Bigcrane and Tamara Enz, The Confederated Salish and Kootenai 

Tribes of the Flathead Reservation, Montana 

Carrie Cordova, Columbia Basin Fish and Wildlife Office, Spokane, 

Washington 

Karen Gray, and Janice Hill, Idaho Conservation Data Center 

Mike Hays, Nez Perce National Forest, Idaho 

Trish Heekin, Latah County Soil and Water Conservation District, Idaho 

Jerry Hustafa and Gene Yates, Wallowa-Whitman National Forest, Oregon 

Peter Lesica, Consultant, Montana 

Maria Mantas, The Nature Conservancy of Montana 

Blair McClarin and Angela Sondenaa, Nez Perce Tribe, Idaho 

Gary Miller, La Grande Fish and Wildlife Office, Oregon 

Scott Mincemoyer and Sue Crispin, Montana Natural Heritage Program 

Robert Taylor, The Nature Conservancy of Oregon 

U.S. Fish and Wildlife Service Ecological Services Offices (Boise, Idaho; 

Helena and Kalispell, Montana; La Grande, Oregon; Spokane and Lacey, 

Washington) 

Jim White and Jerome Hansen, Idaho Department of Fish and Game 

Jean Wood, Umatilla National Forest, Oregon and Washington 
Region 1

U.S. Fish and Wildlife Service

Ecological Services

911 NE. 11th Avenue

Portland, Oregon 97232-4181

September 2007