U.S. Fish & Wildlife Service

Draft Recovery Plan 

for Silene spaldingii

(Spalding’s Catchfly)

Silene spaldingii/Edna Rey-Vizgirdas; Inset/Gina Glenne
Draft Recovery Plan 

for 

Silene spaldingii

(Spalding’s Catchfly) 

Region 1 

U.S. Fish and Wildlife Service 

Portland, Oregon 

Approved: XXXXXXXXXXXXXXXXXXXXXXXXXXXXXX

 Regional Director, U.S. Fish and Wildlife Service 

Date: XXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
Draft Recovery Plan for Silene spaldingii ! October 2005 

i 

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. 2005. Draft Recovery Plan for Silene spaldingii 

(Spalding’s Catchfly). U.S. Fish and Wildlife Service, Portland, Oregon. 121 

pp. 

Electronic copies of this document will be made available at: 

http://endangered.fws.gov/recovery/index.html 
Draft Recovery Plan for Silene spaldingii ! October 2005 

ii 

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. 

Julie Anderson and Mike Finch

Swanson Lakes Wildlife Area 

Barbara Benner and Company 

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 

LeeAnn Eno 

Idaho Bureau of Land Management 

Frank Fink 

Idaho Natural Resources Conservation 

Service 

Zach Funkhouse and Company

Idaho Transportation Department 

Karen Gray

Idaho Conservation Data Center 

Herman Harder 

Adams County Noxious Weed Control 

Board 

Tom Hawkins

Idaho Department of Lands/Craig 

Mountain 

Janice Hill 

Consultant 

Jerry Hustafa 

Wallowa-Whitman National Forest 

Alan and Darla Klages

Private Landowners 

Peter Lesica 

Consultant 

Mark Lowry 

Bureau of Land Management 

Michael Mancuso 

Idaho Conservation Data Center 

Maria Mantas 

The Nature Conservancy of Montana 

Bill Mervyn

Private Landowner 

Gary Miller

La Grande Fish and Wildlife Office 

Kendrick Moholt 

Private Landowner 

Roger Rosentreter

Idaho Bureau of Land Management 

Mike Rule

Turnbull National Wildlife Refuge 
Draft Recovery Plan for Silene spaldingii ! October 2005 

iii 

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 

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 

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
Draft Recovery Plan for Silene spaldingii ! October 2005 

iv 

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 restricted to remnants of grasslands in eastern Washington, northeastern 

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

Columbia, Canada. S. spaldingii was listed as a threatened species under the 

Endangered Species Act on October 10, 2001 (USFWS 2001). There are 

currently 85 known populations of S. spaldingii, with more than half of these (58 

populations) composed of fewer than 100 individuals each. There are an 

additional 20 populations with at least 100 or more individuals apiece, and the 7 

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 

Washington and Idaho; and the Intermontane Valleys of northwestern Montana. 

Habitat Requirements and Limiting Factors: In general Silene spaldingii

is found in open, mesic (moist) grassland communities. However, the species is 

occasionally also found within sagebrush-steppe communities as well as pine 

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

characterized by one or both of two dominant bunchgrass species, Agropyron 

spicatum = Pseudoroegneria spicata (bluebunch wheatgrass) and Festuca 

idahoensis (Idaho fescue). The plant is found at elevations ranging from 420 to 

1,555 meters (1,380 to 5,100 feet), usually in deep, productive loess soils (fine, 

windblown soils). Plants are generally found in swales or on north or east 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 domestic livestock and wildlife 

grazing, and invasions of aggressive nonnative plants. In addition, a loss of 

genetic fitness (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. 
Draft Recovery Plan for Silene spaldingii ! October 2005 

v 

Recovery Priority Number: 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. 

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 on 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 vegetative 

community 

• Adjacent habitat is available 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 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-six 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 prairie, reaching a minimum 

size of 40 acres (16 hectares) of contiguous habitat may not be feasible 
Draft Recovery Plan for Silene spaldingii ! October 2005 

vi 

conservation areas and are distributed throughout the 5 identified 

physiographic provinces as follows: 5 within the Blue Mountain Basins, 6 

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

Intermontane Valleys, and 3 within the Palouse Grasslands. 

The number of 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. 

The validity of preserving the species based on populations composed of at 

least 500 reproducing individuals should be verified by the results of a 

population viability analysis that incorporates threats and further genetic and 

demographic research on Silene spaldingii. The analysis should be initiated 

within 3 years and completed within 15 years of the approval of this recovery 

plan. Once the population viability analysis is completed, the recovery 

criteria listed here will be revisited and the target of 500 reproducing 

individuals per key conservation area may be adjusted, as appropriate. 

2. All 26 key conservation areas of Silene spaldingii are composed of at least 80 

percent native vegetation, 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 (λ ≥ 0) for at least 20 years. 

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., offroad vehicle use, overgrazing by wildlife and domestic stock, herbicide 

application, etc.), protecting pollinators, enacting monitoring strategies, 

incorporating integrated pest management strategies, and incorporating 

appropriate fire management activities. 
Draft Recovery Plan for Silene spaldingii ! October 2005 

vii 

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

been continually controlled or eradicated within a 0.4 kilometer (0.25 mile) 

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

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 will not take place when it may exacerbate invasive 

nonnative plant populations. 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 at 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. 

8. A post-delisting monitoring program for the species is 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 Actions Needed: Silene spaldingii cannot be protected if its habitat is 

not conserved and restored. The goal of this recovery plan is to manage selfsustaining S. spaldingii populations through good habitat (ecosystem) 

management at key conservation areas. This will be accomplished by developing 

and implementing habitat management plans at these key conservation areas that 

provide a strategy for managing S. 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 Silene 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 
Draft Recovery Plan for Silene spaldingii ! October 2005 

viii 

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

spaldingii resides, especially large populations, should be prevented. Livestock 

grazing needs 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 $8,601,500 with an average yearly cost across the first 5 years 

of $349,900. Of the estimated total, roughly a quarter of the dollars are for 

surveys and monitoring. 

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

be possible as early as 2040. Because Silene spaldingii is a long-lived perennial 

species, annual counts vary significantly in response to climatic events (i.e., 

precipitation, temperature), and individuals may exhibit prolonged dormancy for 

up to 3 years, a minimum of 20 years of monitoring will be needed to determine 

long-term population trends. The earliest recovery date accounts for this longterm monitoring as well as the time it may take to supplement or establish new 

populations. 
Draft Recovery Plan for Silene spaldingii ! October 2005 

ix 

TABLE OF CONTENTS 

Executive Summary............................................................................................. iv 

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

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

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

C. Population Trends and Distribution ......................................................... 5 

D. Life History and Ecology......................................................................... 9 

E. Habitat Characteristics/Ecosystems........................................................ 13 

F. Associated Species of Conservation Concern ........................................ 19 

G. Reason for Listing/Threats Assessment................................................. 19 

1. Invasive Nonnative Plants........................................................................20 

2. Problems Associated with Small, Geographically Isolated Populations..23 

3. Changes in the Fire Regime and Fire Effects...........................................26 

4. Land Conversion Associated with Urban and Agricultural Development28 

5. Livestock Grazing and Trampling............................................................29 

6. Herbicide and Insecticide Spraying..........................................................30 

7. Grazing (Herbivory) and Trampling by Wildlife Species........................31 

8. Off-Road Vehicle Use..............................................................................32 

9. Insect Damage and Disease......................................................................32 

10. Impacts from Prolonged Drought and Global Warming ........................33 

11. Inadequacy of Existing Regulatory Mechanisms ...................................33 

H. Conservation Efforts ............................................................................... 34 

1. Inventory Efforts ......................................................................................34 

2. Monitoring Efforts and Demographic Studies .........................................36 

3. Additional Sources of Scientific Information on Silene spaldingii..........37 

4. Invasive Nonnative Plant Control Efforts ................................................38 

5. Additional Conservation Actions .............................................................39 

I. Biological Constraints and Needs............................................................. 40 

II. Recovery Strategy And Goals...................................................................... 41 

A. Recovery Strategy and Rationale........................................................... 41 

B. Recovery Goals, Objectives, And Criteria............................................. 45 

III. Recovery Program....................................................................................... 48 

A. Stepdown Outline of Recovery Actions................................................. 48 

B. Recovery Action Narrative..................................................................... 52 

IV. Implementation Schedule............................................................................. 82 

V. Literature Cited ............................................................................................ 94 

In Litt. References............................................................................................ 111

Personal Communications ............................................................................... 115 

Appendix A. Endangered and Threatened Species Recovery Priority Number 

Guidelines..................................................................................................... 116 

Appendix B. Scientific and Common Names used in Text .............................. 117 

Appendix C. Summary of Threats and Recommended Recovery Actions for 

Silene spaldingii............................................................................................ 120 
Draft Recovery Plan for Silene spaldingii ! October 2005 

x 

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.................. 4 

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

Figure 4. Physiographic regions where Silene spaldingii has been found........... 15 

Figure 5. Known populations of Silene spaldingii............................................... 24 

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

conservation areas within the Blue Mountain Basins physiographic 

region.................................................................................................... 53 

Figure 7. The nine known Silene spaldingii populations and three potential key 

conservation areas identified within the Canyon Grasslands 

physiographic region ............................................................................ 56 

Figure 8. The 35 known Silene spaldingii populations and 10 potential key 

conservation areas identified within the Channeled Scablands 

physiographic region ........................................................................... 59 

Figure 9. The nine Silene spaldingii populations and five potential key 

conservation areas identified within the Intermontane Valleys 

physiographic region ............................................................................ 61 

Figure 10. The 18 Silene spaldingii populations and 2 potential key conservation 

areas within the Palouse Grasslands physiographic region.................. 63 
Draft Recovery Plan for Silene spaldingii ! October 2005 

1 

I. Introduction and Overview 

A. INTRODUCTION 

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

is a regional endemic restricted to remnants of grasslands in eastern Washington, 

northeastern Oregon, west-central Idaho, western Montana, and barely extending 

into British Columbia, Canada. S. spaldingii is impacted by a variety of factors 

including competition with invasive nonnative plants; habitat destruction and 

fragmentation resulting from agricultural and urban development; habitat 

degradation; grazing and trampling by domestic livestock and native herbivores; 

herbicide treatments; annual climactic conditions (i.e., drought cycles); climatic 

change; alterations in fire frequency, intensity, and seasonality; off-highway 

vehicles; and a loss of genetic material associated with small, fragmented 

populations. 

Silene spaldingii was listed as a threatened species under the Endangered 

Species Act on October 10, 2001 (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). 
Draft Recovery Plan for Silene spaldingii ! October 2005 

2 

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) and later described by Sereno Watson 

in 1875, based on the Spalding material (Watson 1875). 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. S. spaldingii 

overlaps in range and is somewhat similar in appearance with S. scouleri, S. 

douglasii, S. cserei, S. oregana, and S. scaposa scaposa var. scaposa (see Figure 

1) (Schassberger 1988; Youtie 1990; Lichthardt 1997). A simple key for 

distinguishing Pacific Northwest bunchgrass Silene is provided in Figure 2. 

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 under unfavorable conditions, such as drought. 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 mile (1.6 kilometers) 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.
Draft Recovery Plan for Silene spaldingii ! October 2005 

3 

Figure 1. Silene spaldingii and a few of its closest look-alikes.
Draft Recovery Plan for Silene spaldingii ! October 2005 

4 

Schematic Silene Flower 

* key compiled by LeAnn Eno, Bureau of Land 

Management, Idaho (Hitchcock et al. 1964; 

Hitchcock and Cronquist 1973; Harris and 

Harris 1994) 

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 ssp. alba) 

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

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

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 – 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 cserei)

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)

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) 

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)

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) 

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) 

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-shaped lobes on the outer margins of the upper part of the 

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

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) 

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) 

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 var. scaposa) 

Figure 2. Dichotomous key for Pacific Northwest Bunchgrass Silene.*
Draft Recovery Plan for Silene spaldingii ! October 2005 

5 

One closely related species, bladder campion (S. latifolia ssp. alba), is an invasive 

nonnative plant. It may be separated from S. spaldingii by bladder campion’s much 

larger, inflated looking flowers. 

Silene spaldingii is an herbaceous perennial, a plant that withers to the ground 

every fall and emerges again in spring. Plants range from 20 to 61 centimeters (8 to 24 

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

light-green stem per plant, but sometimes there may be multiple stems. Each stem bears 

four to seven 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 root 

crown 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 (up to 60) flowers are horizontally positioned near the top of the plant 

in a branched arrangement (inflorescence). Flowers are approximately 1 centimeter (0.5 

inch) long; however, the majority of the flower petal is enclosed within a leaf like tube, 

the calyx, that 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. Below 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; Gamon 1991; Lesica and Heidel 1996; Lichthardt 1997; Hill and Gray 2004a). 

 

C. POPULATION TRENDS AND DISTRIBUTION 

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

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

Sanders), one county in Oregon (Wallowa), and five counties in Washington (Adams, 
Draft Recovery Plan for Silene spaldingii ! October 2005 

6 

Asotin, Lincoln, Spokane, and Whitman) (Idaho Conservation Data Center 2003; 

Montana Natural Heritage Program 2003; Oregon Natural Heritage Program 2003; 

Washington Natural Heritage Program 2003). Only one element occurrence record of S. 

spaldingii is known in British Columbia, Canada, and this site is located within 1 mile 

(1.6 kilometers) of plants in Montana (British Columbia Conservation Data Center 2004), 

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

the rangewide distribution of S. spaldingii. 

The distribution and habitat of Silene spaldingii are primarily restricted to mesic 

slopes, flats or depressions in grassland or steppe vegetation dominated by native 

perennial grasses such as Festuca idahoensis (Idaho fescue) or Festuca 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 

Washington and Idaho; and the Intermontane Valleys of northwestern Montana. The 

Palouse Grasslands, a subset of the Pacific Northwest bunchgrass habitat type (Tisdale 

1986), are believed to have been at the center of S. spaldingii’s historical range. 

Plants are tracked by State or province 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 occurrence records, or 58 

populations if the element occurrence records within 1 mile (1.6 kilometers) 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), 7 in the Intermontane Valleys (excluding 1 historical population and 1 

with poor location records), and 16 within the Palouse Grasslands (excluding 1 extirpated 

population and 1 with poor location records). When examined by state there were 7 

populations in Idaho, 6.53

 in Montana, 9 in Oregon, 35 in Washington, and 0.5 in British 

Columbia, Canada (G. Glenne, in litt. 2004a). Some 16,500 individual plants were 

 

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 mile (1.6 kilometers) (see section D., Life 

History and Ecology, for details). Recent improvements in mapping technology and criteria for designating 

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

the 52 populations originally identified in the Final Rule listing the species (USFWS 2001) would have 

been more accurately reported as 58 populations. 

3

 One population spans the border of the United States and Canada, reported here as 0.5 population. 
Draft Recovery Plan for Silene spaldingii ! October 2005 

7 

Figure 3. Rangewide distribution of Silene spaldingii.
Draft Recovery Plan for Silene spaldingii ! October 2005 

8 

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. 

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

habitat have resulted in the identification of 27 new populations. Today we have 124 

separate element occurrence records of S. spaldingii in 85 populations (Figure 3): 14 in the 

Blue Mountain Basins, 9 in the Canyon Grasslands, 35 in the Channeled Scablands, 9 in 

the Intermontane Valleys, and 18 in the Palouse Grasslands. When examined by state, 

there are 13 populations in Idaho, 8.5 in Montana, 14 in Oregon, 49 in Washington, and 

0.5 in British Columbia, Canada (G. Glenne, in litt. 2004a). The number of individual 

plants in each population may range from one to several thousand. None of the newly 

discovered populations has resulted in any significant range extension, nor are they 

indicative of an increase in plant vigor. The current estimated number of plants is 

approximately 24,500 individuals, again a rough approximation. 

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-one of the known populations of S. spaldingii (36 percent) occur on lands that are 

entirely in private ownership, with an additional 19 populations (22 percent) in partial 

private ownership (G. Glenne, in litt. 2004a). 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 7 populations of Silene spaldingii that may be considered 

relatively large, each with over 500 individuals (G. Glenne, in litt. 2004a). The largest 

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

Preserve in Montana, followed by Garden Creek, Idaho, with approximately 4,000 plants. 

The other 5 large populations range from 500 plants at Coal Creek, Washington, to some 

1,613 individuals at The Nature Conservancy’s Zumwalt Prairie Preserve in Oregon. 

Approximately 75 percent of the total known individuals of S. spaldingii are found within 

these few large populations. Of the 85 known S. spaldingii populations, just over twothirds (58 populations, or 68 percent) are small populations, each made up of fewer than 

100 individuals (G. Glenne, in litt. 2004a). Furthermore, much of the remaining habitat 

occupied by S. spaldingii is fragmented. For example, S. spaldingii populations in 

Oregon are located at least 64 kilometers (40 miles) from the nearest known populations 

in eastern Washington. When such small populations with few individuals are isolated 

and genetic exchange is not possible, they become vulnerable to the loss of genetic 
Draft Recovery Plan for Silene spaldingii ! October 2005 

9 

variation and, ultimately, the loss of the population itself (Barrett and Kohn 1991; 

Ellstrand and Elam 1993; 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 since European 

settlement of this region. Historical documentation indicates the species has always been 

relatively rare (Hitchcock and Maguire 1947), 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 95 percent of the 

original Palouse Prairie and 47 percent of the Channeled Scablands habitat has been lost 

(Noss et al. 1995), with obvious ramifications for S. spaldingii. Today there are half as 

many known S. spaldingii populations (18 versus 35) within the Palouse Grasslands as the 

Channeled Scablands, but only a tenth of the plant numbers (477 versus 4,313,) indicating 

some measure of the loss of suitable habitat within the Palouse Grasslands and the 

extremely small size of the remnant populations there. Other areas such as the Canyon 

Grasslands have undergone a less dramatic land-use conversion, but have been and 

continue to be affected by livestock grazing and nonnative plant invasions. 

Four population extirpations have been documented since tracking of Silene 

spaldingii began in the early 1980’s (Schassberger 1988; Gamon 1991; Idaho 

Conservation Data Center 2003; Montana Natural Heritage Program 2003; Oregon 

Natural Heritage Program 2003; Washington Natural Heritage Program 2003). At least 

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

plants present at the last visit (Washington Natural Heritage Program 2003). 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 such sites. 

D. LIFE HISTORY AND ECOLOGY 

At the end of a 5-year demography study, 72 percent of Silene spaldingii plants 

remained alive (Lesica 1997), suggesting that individuals regularly reach an age of 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), but generally flowering does not occur until during 

or after the third season (Lescia 1997). Adult plants emerge in spring, usually May, as 
Draft Recovery Plan for Silene spaldingii ! October 2005 

10 

either a stemmed plant, a rosette, or occasionally as a plant with both rosette(s) and 

stem(s) (Hill and Weddell 2003). 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). 

Silene spaldingii exhibits prolonged or summer dormancy; that is, plants can 

remain below the ground, without leaves, for up to 3 years when conditions are 

unfavorable (Lesica and Steele 1994; Lesica 1997). These unfavorable conditions are 

thought to be correlated with drought, although this is unclear. A preliminary analysis 

suggests prolonged dormancy tends to be higher in summers preceded by a wet summer 

and dry fall (P. Lesica, in litt. 2003). This prolonged dormancy can make population 

estimates and monitoring difficult. In one demography study, dormancy varied from a 

yearly low of 11 percent of individuals dormant to a high of 74 percent (Lesica 1997). 

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, in litt. 2003). 

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. Plants are generally just taller than surrounding vegetation (Gamon 1991), and the 

seeds are small, flat, and somewhat winged. The 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 

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

passage through the digestive tract of herbivores. 

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 indicate some germination could occur in fall (Lesica 1988a, 1993). 

Lesica’s (1988a, 1993) 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 

1988a, 1993). 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). 
Draft Recovery Plan for Silene spaldingii ! October 2005 

11 

In a demography study, Lesica (1997) 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. After germination, Lesica (1988a) 

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 re-growth would reflect fall growth (Lesica 1988a). 

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 (Hill and Weddell 2003; P. Lesica, in litt. 2003), adult rosettes with a conspicuous 

lack of stem material between the leaves (Hill and Weddell 2003; Hill and Gray 2004b), 

seedling rosettes with hairless leaves (Hill and Gray 2000; P. Lesica, in litt. 2003, Hill 

and Weddell 2003), seedling leaves with hairs only along the edges (Hill and Gray 

2004b), and leaf size (Hill and Weddell 2003). None of these techniques are definitive 

and persons performing monitoring for the species should be aware of this constraint. 

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

reproduction (spread by vegetative growth) (Lesica 1993). The species is partially selfcompatible, 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 becoming receptive (Lesica 1988b). 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) 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). Lesica and Heidel (1996) 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 

suggested that these bumblebees preferred the nonnative invasive plant Hypericum 

perforatum (St. Johnswort) over S. spaldingii (Lesica and Heidel 1996). 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 impact reproduction, and pollinators must consistently 

visit S. spaldingii. 
Draft Recovery Plan for Silene spaldingii ! October 2005 

12 

Pollinators were observed for over 20 hours 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). 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. 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. Night pollination 

studies have not been performed. 

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

except the extreme south (Thorpe et al. 1983). 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 foot (0.3 meter) of soil (Hobbs 1966). 

The queen emerges from hibernation in spring and establishes a seasonal colony that can 

contain over 200 individuals by fall (Hobbs 1966). 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 (Thorpe et al. 1983). 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). 

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. One study 

documented that bees fly 1 kilometer (0.6 mile) or less (Steffan-Dewenter and Tscharntke 

1999). In another study, the bumblebee Bombus terrestris did not fly more than a 

distance of 621 meters (2,037 feet; Osborne et al. 1999). Another bumblebee pollinated 

plant species, Scabiosa columbaria, 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). These studies suggest that 

genetic exchange via pollen transfer may be extremely rare for distances over 1 mile (1.6 

kilometers, or 1,600 meters). This is one of the rationales we used when grouping Silene 

spaldingii sites within 1 mile (1.6 kilometers) of one another as populations. 

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 found that genetic diversity of S. spaldingii was comparable to 

that of other rare Silene (S. regia and S. hawaiiensis), as well as other more common 
Draft Recovery Plan for Silene spaldingii ! October 2005 

13 

species in the genus (Dolan 1994; Westerbergh and Saura 1994). 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’s (1996) study, which reported lower 

pollinator visitation rates and a higher incidence of fruit abortion at the Dancing Prairie 

site. The Baldwin and Brunsfeld (1995) study 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 420 to 1,555 meters (1,380 to 5,100 

feet) (Idaho Conservation Data Center 2003; Montana Natural Heritage Program 2003; 

Oregon Natural Heritage Program 2003; Washington Natural Heritage Program 2003). 

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); anywhere from 45 to 65 

percent of the precipitation occurs during the winter months (Daubenmire 1942; 

Mueggler and Stewart 1980). A drought period occurs in mid and late summer when 

precipitation is minimal and temperatures are high (Tisdale 1983). 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). S. 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). 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). 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). 

Silene spaldingii is generally found in deep loamy soils (fertile soils comprised 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). 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 (Agropyron 

spicatum = Pseudoroegneria spicata) communities (Johnson and Simon 1987). Soils in 

the tri-state (Idaho, Oregon and Washington) area are loess (wind-dispersed) and ash 

(from volcanic eruptions) influenced (Tisdale 1986a; Johnson and Simon 1987), while 

soils in Montana are more glacially influenced (Schassberger 1988). S. spaldingii is 

found on a wide range of slopes, from flat areas to slopes as great as 70 percent. Most 
Draft Recovery Plan for Silene spaldingii ! October 2005 

14 

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

2004a), although this may be an artifact of where intact habitat has not been converted to 

other uses. 

Silene spaldingii is found primarily within the plant association known as the 

Pacific Northwest Bunchgrass Grasslands, extending from Washington and Oregon into 

parts of Montana and into adjacent British Columbia and Alberta, Canada (Tisdale 1983). 

This area has mistakenly, at times, been broadly described as the “Palouse Prairie” or the 

Palouse region (Tisdale 1983; Lichthardt and Moseley 1997; USFWS 2001). 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 are characterized by one or both of two main bunchgrass 

species, Agropyron spicatum (bluebunch wheatgrass) and Fesctuca idahoensis (Idaho 

fescue), with Festuca idahoensis sometimes co- or subdominant with Festuca scabrella

(rough fescue) in Montana (Tisdale 1983). 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). Exceptions include the Dancing 

Prairie in Montana and Turnbull National Wildlife Refuge in Washington. 

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) Agropyron spicatum – Festuca idahoensis or Festuca idahoensis – 

Agropyron spicatum; and 5) Festuca scabrella (Daubenmire 1970; Mueggler and Stewart 

1980; Tisdale 1986b; Johnson and Simon 1987). Primary shrub habitats include: 1) 

Artemesia tridentata (big sagebrush) – Festuca idahoensis; and 2) Artemesia tripartita

(three-tip sagebrush) – Festuca idahoensis. Primary forest habitat types include: 1) Pinus 

ponderosa (ponderosa pine) – Festuca idahoensis; and 2) Pinus ponderosa – 

Symphoricarpos albus. Seventy-three percent of known Silene spaldingii occurrences are 

within grassland habitat types, 20 percent within shrub habitat types, and 7 percent within 

forest habitat types (summarized by Hill and Gray 2004a). Some of the most difficult 

nonnative invasive plants to control in S. spaldingii habitat include Centaurea solstitialis

(yellow starthistle), Cardaria draba (whitetop), Centaurea maculosa (spotted knapweed), 

Euphorbia esula (leafy spurge), Hypericum perforatum (St. Johnswort), 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 
Draft Recovery Plan for Silene spaldingii ! October 2005 

15 

Figure 4. Physiographic regions where Silene spaldingii has been found. 
Draft Recovery Plan for Silene spaldingii ! October 2005 

16 

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, and were delineated by taking the physiographic 

regions from Hill and Gray (2004a) and relating the regions to the more widely used 

Level IV Ecoregions for each state (U.S. Environmental Protection Agency 2004). 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). The lowest elevation (420 meters [1,380 feet)] population of S. spaldingii occurs 

within the Canyon Grasslands (Idaho Conservation Data Center 2003). The dramatic 

range in 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). 

Within the Canyon Grasslands, Silene spaldingii is found at elevations from 420 

to 1,220 meters (1,380 to 4,000 feet) on northerly slopes that support more mesic Festuca 

idahoensis communities. Because of their steep nature, 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 have formed similarly to the Palouse Grasslands except 

that massive flooding, associated with bursting ice dams in the last ice age 12,000 to 

16,000 years ago, has scoured the area (Mueller and Mueller 1997). This scouring has 
Draft Recovery Plan for Silene spaldingii ! October 2005 

17 

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). An interesting landscape feature of the Channeled Scablands is 

referred to as “biscuit and swale” topography, commonly used to describe small biscuitlike 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). Like the Palouse Grasslands, the loess islands that remain in the 

Channeled Scablands are fertile and consequently have been largely converted to 

agriculture. 

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 sides of biscuits (B. Benner, in 

litt. 1993). 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). 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. 

Glacial sediments that are generally less fertile than loess or ash deposits comprise the 

soils (Daubenmire 1970). 

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). An underlying 

basalt layer is covered with deep deposits of loess and ash, forming long undulating 
Draft Recovery Plan for Silene spaldingii ! October 2005 

18 

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), and have high 

moisture-holding capacity and water infiltration rates (Johnson and Simon 1987). 

Occasionally tall granitic hills (“steptoes”) protrude above the undulating dunes. 

Beginning in 1880, the Palouse Grasslands have undergone a dramatic conversion to 

farm lands. So much so, it is estimated that today only 0.1 percent of the grasslands 

remain in a natural state (Noss 1995; Noss et al. 1995). The remains of the Palouse 

Grasslands include small remnants in rocky areas or at field corners (Daubenmire 1970; 

Tisdale 1986b). 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; 

Lichthardt and Moseley 1997). 

Silene spaldingii within the Palouse Grasslands is restricted to small fragmented 

populations (“eyebrows5,” 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, 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 its highest known 

elevation (1,555 meters [5,100 feet]) within the Blue Mountain Basins, specifically the 

Wallowa Valley (Oregon Natural Heritage Program 2003). 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). 

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. 

 

5

 “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. 
Draft Recovery Plan for Silene spaldingii ! October 2005 

19 

Rangewide suitable habitat for Silene spaldingii would include all flat and 

northern slopes between 420 to 1,555 meters (1,380 to 5,100 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 vast tracts of suitable habitat for S. spaldingii on private and public 

lands within the Canyon Grasslands, Channeled Scablands, Intermontane Valleys, 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. 

F. ASSOCIATED SPECIES OF CONSERVATION CONCERN 

Rare animal species that occur within Silene spaldingii’s range include the 

Columbian sharp-tailed grouse (Tympanuchus phasianellus columbianus). Rare endemic 

plant species include Aster jessicae (Jessica’s aster), Astragalus riparius (Piper’s milkvetch), Calochortus macrocarpus var. maculosus (green-band mariposa lily), 

Calochortus nitidus (broad-fruit mariposa), Cirsium brevifolium (Palouse thistle), 

Haplopappus liatriformis (Palouse goldenweed), Polemonium pectinatum (Washington 

polemonium), Rubus nigerrimus (Northwest raspberry), and Trifolium plumosum var. 

amplifolium (plumed clover) (Hill and Gray 2004a). 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 the 

rare species listed above. 

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: 

 

A ⎯ The present or threatened destruction, modification, or curtailment of habitat 

or range; 

B ⎯ Overutilization for commercial, recreational, scientific, or educational 

purposes; 

C ⎯ Disease or predation; 

D ⎯ The inadequacy of existing regulatory mechanisms; and 

E ⎯ Other natural or man-made factors affecting the continued existence of a 

species. 
Draft Recovery Plan for Silene spaldingii ! October 2005 

20 

 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). 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). Centaurea maculosa (spotted knapweed) 

is considered to be “the number one weed problem on rangeland in western Montana” 

(Whitson et al.1996) and has infested more than 1,900,000 hectares (4,700,000 acres) in 

the state (Westbrooks 1998). And, 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). 

Many experts believe that following habitat destruction, invasive nonnative plants 

are the next greatest threat to biodiversity (Randall 1996). 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 habitat (Hill and Gray 2004a). 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 2003). 

Invasive nonnative plants detrimentally affect native plants, including rare plants 

like Silene spaldingii, through competitive exclusion, niche displacement, hybridization, 

and changes in insect predation; examples are widespread among taxa and locations or 

ecosystems (D’Antonio and Vitousek 1992; Olson 1999; Mooney and Cleland 2001). 

Examples of rare plants being affected by invasive nonnative plants follow. 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). In another 

study, Huenneke and Thomson (1995) 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) found that 

Centaurea maculosa reduced recruitment and population growth of the rare Arabis 

fecunda (Mt. Sapphire rockcress). 

Annual invasive nonnative grasses co-occur with Silene spaldingii at most if not 

all populations and pose a threat to the species. They are most commonly represented by 

Bromus japonicus (Japanese brome), Bromus secalinus (cheat), Bromus tectorum

(cheatgrass), and Ventenata dubia (ventenata) (Hill and Gray 2004a). Bromus tectorum, 

for example, has contributed to the widespread degradation of native rangelands 
Draft Recovery Plan for Silene spaldingii ! October 2005 

21 

throughout the 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). 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; see Section G-3). 

Rhizomatous6 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, 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). 

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). 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 (Idaho Conservation Data Center 2003), 

Centaurea solstitialis spread from approximately 60 hectares (150 acres) in 1987 to 810 

hectares (2,000 acres) in 1998 (J. Hill, in litt. 1999). 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). 

Centaurea solstitialis is found in the vicinity of all Silene spaldingii populations 

in Idaho (Lichthardt 1997). 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 

 

6

 “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. 
Draft Recovery Plan for Silene spaldingii ! October 2005 

22 

solstitialis or other invasive nonnative winter annuals (Lichthardt 1997). The seeds of 

Centaurea solstitialis can remain dormant in the soil for 10 years (Callihan and Miller 

1997), making effective control of this invasive nonnative plant difficult. Previously, 

most Centaurea solstitialis within the Canyon Grasslands was restricted to southern 

slopes where S. spaldingii generally does not occur (Roché 1965). However, in recent 

years Centaurea solstitialis is expanding its ecological amplitude and invading the 

northern slopes as well (Hill and Gray 2000). 

 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, although all 

Centaurea solstitialis and Bromus tectorum infestations were at least 2 meters (6.5 feet) 

away from existing S. spaldingii individuals (Menke 2003). The researcher proposed that 

the similarity in vigor of S. spaldingii plants may have been due to the relative site 

productivity, or that S. spaldingii and the invasive nonnative plants partition resources 

differently in space or time. Invasive nonnative plant effects on recruitment of S. 

spaldingii were not measured in this study. Alternatively, another study found that the 

greater the invasive nonnative plant cover, the lower the vigor of S. spaldingii at the 

Fairchild Air Force Base in Washington (Caplow 2002a). 

 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). 

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). 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). 

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 can 

decrease biodiversity and compete with native plants (summarized by Harrison et al.

1996). For example, Agropyron stands in 1966 in southern Idaho had already persisted 

for 30 to 50 years and were spreading into adjacent habitats (Hull and Klomp 1966, 

1967). Other studies have also found nonnative planted grasses invading adjacent native 
Draft Recovery Plan for Silene spaldingii ! October 2005 

23 

communities (D’Antonio and Vitousek 1992). The planting of nonnative range grasses is 

thought to have eliminated habitat for S. spaldingii in several locations across its range, 

particularly in the Channeled Scablands (B. Benner in litt. 1993, 2003; B. Weddell in litt. 

2003; Washington Natural Heritage Program 2003). Nonnative grasses are being planted 

at Corral Creek, near S. spaldingii sites in Idaho, and spreading along road corridors (K. 

Gray, in litt. 2004). For these reasons, nonnative grasses should not be used for 

restoration near S. spaldingii sites. 

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; Lichthardt 1997; Idaho Conservation Data Center 2003; 

Montana Natural Heritage Program 2003; Oregon Natural Heritage Program 2003; 

Washington Natural Heritage Program 2003; Hill and Gray 2004a). If populations are 

defined by grouping together sites within 1 mile (1.6 kilometers) of one another (a long 

distance for pollen transfer), there are 85 known populations of S. spaldingii. Of these 85 

populations, 48 (56 percent) have fewer than 50 plants, and another 10 populations have 

100 or fewer individuals, meaning that 68 percent of the populations have 100 or fewer 

individual plants overall (Figure 5) (G. Glenne, in litt 2004a). 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). 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. Such 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. 

 Small populations are vulnerable to relatively minor environmental disturbances 

such as fire, herbicide drift, and nonnative plant invasions (Gamon 1991) and are subject 

to the loss of genetic diversity from genetic drift and inbreeding (Ellstrand and Elam 

1993). 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). Smaller populations generally have lower genetic 

diversity, and lower genetic diversity may in turn lead to smaller populations by 
Draft Recovery Plan for Silene spaldingii ! October 2005 

24 

Figure 5. Known populations of Silene spaldingii. 
Draft Recovery Plan for Silene spaldingii ! October 2005 

25 

decreasing the species’ ability to adapt: a negative feedback loop. 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). 

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. Often the fragments are not of sufficient size to support 

the natural diversity prevalent in an area and so exhibit a decline in biodiversity (Soulé 

1987; Noss and Cooperrider 1994). Habitat fragments are often functionally smaller than 

they appear because edge effects impact the available habitat within the fragment (Lienert 

and Fischer 2003), and intense agricultural practices will affect adjacent fragments 

(Boutin and Jobin 1998). Habitat fragmentation has been shown to disrupt plantpollinator interactions and predator-prey interactions (Steffan-Dewenter and 

Tscharntke1999) and alter seed germination percentages (Menges 1991a). 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). 

 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). Lowered seed germination percentages were 

found in smaller prairie fragments of Silene regia (royal catchfly) (Menges 1991a). 

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). Plants that were less capable of self-fertilization showed 

strongly reduced population viability with pronounced extinction thresholds at high levels 

of fragmentation (Lennartsson 2002). 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; Richards 1997). 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 mile (1.6 

kilometers; 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; Lesica and Heidel 1996; 

Baldwin and Brunsfeld 1995). 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; Lesica and Heidel 1996). In addition to 

agricultural conversion and pesticides, pollinators are vulnerable to plant herbicide 
Draft Recovery Plan for Silene spaldingii ! October 2005 

26 

applications, domestic livestock grazing, and fire, and these potential impacts to 

pollinators must therefore be considered in conservation strategies for S. spaldingii

(Gamon 1991; Lesica 1993). 

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 (Landres et al. 1999). Fire 

regimes within Silene spaldingii habitat in the western United States have been highly 

disrupted (Whisenant 1990; D’Antonio and Vitousek 1992; Mutch et al. 1993; Narolski 

1996; Weddell 2001; Hilty et al. 2004). In some instances, fire suppression has allowed 

grasslands to be invaded by trees (Menges 1995; Conner et al. 2001; Lesica 1997, 1999; 

Lesica and Martin 2003). At the same time, in many grassland and shrub habitats fire 

frequencies have increased because of annual nonnative grass invasions (Whisenant 

1990; D’Antonio and Vitousek 1992; Hilty et al. 2004). These annual nonnative invasive 

grasses 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 rangewide (Hill and Gray 2004a). 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). 

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; Menke and Muir 

2004). S. 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; Hill and Weddell 2003; Menke 

2003; Hill and Gray 2004b). Fire apparently broke prolonged dormancy, so that plant 

numbers were higher the year subsequent to a fire in both Idaho and Montana (Lesica 

1999; Hill and Fuchs 2003; Menke 2003), and more flowers were produced per plant 

after a fire (Lesica 1999; Hill and Weddell 2003), although fewer of these flowers 

developed mature fruit (Menke 2003). 

Study results differed between the sites in that in Montana, Silene spaldingii 

seedling recruitment was significantly higher after fire, whereas in Idaho it was not (Hill 

and Weddell 2003). 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 idahoensis-dominated grasslands in Idaho (1.3 centimeters [0.5 

inch]) (Hill and Weddell 2003; Hill and Gray 2004a). Greater litter depth affects S. 

spaldingii seedling recruitment because it is difficult for seedlings to germinate under and 

grow through a dense litter layer (Lesica 1999; Hill and Gray 2004a). While fire appears 
Draft Recovery Plan for Silene spaldingii ! October 2005 

27 

necessary for maintaining grasslands and preventing tree and shrub encroachment in 

Montana (Lesica 1999), it may not be important in maintaining the drier grasslands 

within the Canyon Grasslands where a lack of moisture is thought to preclude tree and 

shrub invasion (Daubenmire 1970; Tisdale 1986b; Weddell 2001; Hill and Gray 2004a). 

Nonnative plant invasions are affected by fires, both natural and prescribed, 

within Silene spaldingii habitat. Lesica and Martin (2003) 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. 2001). 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). 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 Agropyron spicatum (bluebunch wheatgrass), exotic grasses, and other forb 

species 2 years after a fire (Menke 2003). At one site in Washington, a prescribed burn 

escaped in 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, 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) 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 such a 

physical record. 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; J. White, in litt. 2003), to infrequently (Weddell 2001). Weddell 
Draft Recovery Plan for Silene spaldingii ! October 2005 

28 

(2001) 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. 

 With or without accurate fire frequency data, Silene spaldingii does appear to be 

able to tolerate some fire (Lesica 1999; Hill and Fuchs 2003; Hill and Weddell 2003; 

Menke 2003). 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 1997). 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 disturbanceadapted species can be promoted by fire (Christensen and Burrows 1986; Hobbs and 

Huenneke 1992; Lesica and Martin 2003). 

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 31 populations of S. spaldingii (36 percent) of those known to 

remain today occur entirely on privately owned lands, with an additional 19 populations 

(22 percent) in partial private ownership (G. Glenne, in litt. 2004a). These populations 

are currently affected by changes in land use practices, including certain livestock 

grazing practices, 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 two decades in all 

counties where S. spaldingii resides (Hill and Gray 2004a). 

 Active housing development threatens to eliminate Silene spaldingii habitat near 

Redbird Ridge in Idaho (Lichthardt 1997). Unsurveyed residential developments 

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, in litt. 1998). 

Continued development in this area is expected (B. Martin, in litt. 1998). S. spaldingii on 

private land near Wallowa Lake in eastern Oregon, one of the 7 sites with over 500 

individuals, may be threatened by development (Oregon Natural Heritage Program 2003). 

Other S. spaldingii sites on private land in Idaho, Montana, and Washington are also 

threatened by development. 
Draft Recovery Plan for Silene spaldingii ! October 2005 

29 

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 in litt. 2004b). 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). 

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

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). 

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; Crone 

2001), and Lesica (1997) 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 caudex7

, potentially killing the 

plant (B. Benner, in litt. 1995, 2003). 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). Trampling by livestock may also 

threaten the nests of ground dwelling pollinators of S. spaldingii, including the 

bumblebee Bombus fervidus (Sugden 1985; Lesica 1993; Lesica and Heidel 1996). 

More important than direct consumption or trampling impacts to Silene spaldingii

is the habitat degradation associated with livestock disturbances (summarized by 

Fleischner 1994 and Jones 2000). 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, hooved animals (Mack and Thompson 1982) and 

so are impacted more severely by livestock grazing. Disturbances, most frequently 

linked to livestock grazing, 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 (Bock et 

al. 1993; J. DiTomaso, in litt. 2000; Knick et al. 2003). For example, the initial 

introduction and spread of the most prevalent invasive nonnative annual grass, Bromus 

tectorum (cheatgrass), throughout the range of S. spaldingii is attributed to overgrazing 

by livestock that occurred at the end of the 1800s and early 1900s (Mack 1981) (see the 

 

7

 The caudex is the root crown, the persistent and often woody base of an otherwise herbaceous perennial 

plant. 
Draft Recovery Plan for Silene spaldingii ! October 2005 

30 

section “Invasive Nonnative Plants” above for a better discussion on the effects of 

Bromus tectorum). Research on the nonnative Centaurea maculosa (spotted knapweed) 

and native grass Festuca idahoensis (Idaho fescue) found that sheep preferred F. 

idahoensis, and so accelerated the invasion of C. maculosa through selective grazing 

(Olson et al. 1997). 

Livestock grazing has coexisted with Silene spaldingii for over 150 years, or an 

estimated seven generations of S. spaldingii (Mack 1981). The relatively long life span 

of this herbaceous perennial and its long taproot has likely helped S. spaldingii withstand 

some livestock grazing impacts. Without good historical population number estimates 

for comparison from the time prior to the initiation of livestock grazing, it is difficult to 

assess the expected declines over time. Instead, we must use shorter term, more evident 

losses such as loss of reproductive structures, individuals, and habitat degradation to infer 

an impact to S. spaldingii from livestock grazing. This is not to say that properly 

managed livestock grazing in conjunction with a good management program for invasive 

nonnative plants is not compatible with conservation of S. spaldingii. 

6. Herbicide and Insecticide Spraying (Factor E) 

Herbicide and insecticide spraying is a problem for Silene spaldingii both within 

contiguous wild lands as well as more fragmented landscapes. This problem 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 S. spaldingii’s range 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-of-ways, spray herbicides and 

pesticides without first surveying for S. spaldingii (J. White, in litt. 2003). In some 

instances these landowners are aware that S. spaldingii may occur within their ownership, 

and in other instances landowners may be unaware that the species occurs on their 

property. 

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). 

Another listed Canyon Grassland plant species, Mirabilis macfarlanei (Macfarlane’s 

four-o’clock), was accidentally aerially sprayed in 1997 (C. Johnson, in litt. 1997). 

Herbicide spraying effects on S. spaldingii have not been researched, although it is 

reasonable to assume that broad spectrum herbicides such as glyphosate, picloram, and 
Draft Recovery Plan for Silene spaldingii ! October 2005 

31 

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). 

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 drift 

threatens populations in Idaho (Lichthardt 1997; J. Hill, in litt. 1999), Oregon (J. Hustafa, 

U.S. Forest Service, pers. comm. 1999; J. Kagan, Oregon Natural Heritage Information 

Center, pers. comm. 1998), and Washington (Washington Natural Heritage Program 

2003). 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). 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). 

Grasshopper and other insect control programs generally utilize broad spectrum 

insecticides that will affect native bee species (Johansen et al. 1983). The effects of 

insect control programs on S. spaldingii’s pollinators 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; Lesica 

and Heidel 1996). 

7. Grazing (Herbivory) and Trampling by Wildlife Species (Factor C) 

 Grazing or browsing of Silene spaldingii inflorescences by native herbivores has 

been observed and is considered a threat to the species (Kagan 1989; Lesica 1993; Heidel 

1995; B. Benner, in litt. 1999; Hill and Weddell 2003; Hill and Gray 2004a,b). 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. For example, elk numbers 

are generally thought to have been historically low at Craig Mountain, Idaho; this is 

extrapolated from historical reports such as Lewis and Clark’s comments on the paucity 

of wildlife along the Clearwater River in 1805 (Idaho Department of Fish and Game 

2003). Elk were virtually absent from the Craig Mountain area until the 1960s (Idaho 

Department of Fish and Game 2003). In 1992 the Bonneville Power Administration 

purchased 60,000 acres on Craig Mountain for the State of Idaho as wildlife habitat (U.S. 

Bonneville Power Administration 2003). Elk herds have doubled over the last 20 years, 

with over 3,500 elk in the “Hells Canyon Zone” surrounding and including Craig 
Draft Recovery Plan for Silene spaldingii ! October 2005 

32 

Mountain, and further increases are expected (Idaho Department of Fish and Game 

2003). Long-term 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 Gray 2000; Hill and Weddell 2003; Hill and Gray 2004b). At the 

Kramer Prairie site in Washington, heavy grazing has occurred where livestock is 

excluded; deer are thought to be the cause (Wentworth 1996). 

 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; 

Caplow 2001; Hill and Gray 2004b). 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). 

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 (Idaho Conservation Data Center 2003; Washington 

Natural Heritage Program 2003). At the site in Idaho, off-road vehicle use is thought to 

be the primary threat to S. spaldingii (Idaho Conservation Data Center 2003). 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 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; Kagan 1989; Youtie 1990; Gamon 

1991; Lichthardt 1997; B. Benner, in litt. 1999; S. Riley, U.S. Forest Service, pers. 

comm. 1999; Hill and Gray 2000, 2004; Hill and Weddell 2003; R. Taylor, in litt. 2003; 

P. Lesica in litt. 2004). Predation on seed capsules has been documented to be as high as 

90 percent at the Kramer Prairie, Washington, site (Heidel 1979), although lower 

percentages are more common. Most insect predation seems to be from larva (Hill and 

Gray 2000; P. Lesica, in litt. 2004), although a seed weevil (Kagan 1989; Youtie 1990) 

and some other beetles (Heidel 1979) 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. 
Draft Recovery Plan for Silene spaldingii ! October 2005 

33 

A fungal rust has been found on Silene spaldingii plants in Washington (B. 

Benner, in litt. 2004). It is unknown how this rust may be affecting the species or how 

often it occurs. 

 10. Impacts from Prolonged Drought and Global Warming (Factor E) 

Silene spaldingii has adapted to drought, evident in its prolonged dormancy 

response. Prolonged dormancy is a great asset because it increases the likelihood of adult 

survival and therefore minimizes 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). Prolonged periods of drought will increase 

the numbers of dormant individuals at a S. spaldingii site (Heidel 1995; Lesica 1997; B. 

Benner, in litt. 1999), limiting the number of individuals reproducing, which could make 

small populations more susceptible to extinction. Based on demographic studies of 

mapped individuals of S. spaldingii, Lesica (1997) considered plants that failed to 

reappear after 3 consecutive years to be dead. 

Causes aside, global temperatures are increasing (U.S. Environmental Protection 

Agency 2000). The effects of this global warming are speculative, but it has the potential 

to affect rare plants such as Silene spaldingii. Researchers speculate that global warming 

will alter rainfall patterns, with some regions becoming drier and others wetter (Given 

1994). Within the Pacific Northwest a recent model predicts warmer and wetter winters 

in 80 years (U.S. Department of Energy 2004). Because plants are stationary and can’t 

easily move with a shifting climate, it is believed they are more susceptible to global 

warming than wildlife species (Wilson 1989). 

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). 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. Therefore, S. 

spaldingii is not legally protected on any State or private lands. Silene spaldingii is not 

afforded protection by either the Species at Risk Act or the Canada Wildlife Act in 

Canada (Douglas et al. 2002). 
Draft Recovery Plan for Silene spaldingii ! October 2005 

34 

Special Federal land designations such as Areas of Critical Environmental 

Concern, Research Natural Areas, and Botanical Special Interest Areas have not been 

designated within Silene spaldingii habitat except at Coal Creek, Washington, where an 

Area of Critical Environmental Concern has been established. 

No protection is provided by State Natural Heritage Programs and Conservation 

Data Centers. 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 

Surveys for Silene spaldingii are being conducted on most 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. Although in general grazing allotments on federally 

managed lands have not been inventoried, grazing lease renewals are being surveyed in 

Washington (B. Benner, in litt. 2004) and in Oregon (G. Yates, in litt. 2004). 

(a) Idaho. Within Idaho, extensive inventories have been conducted in the Craig 

Mountain Canyon Grasslands by The Nature Conservancy on their Garden Creek Ranch, 

by the Bureau of Land Management, during the course of a master’s thesis project 

(Menke 2003), and by the Idaho Conservation Data Center. The Idaho Conservation 

Data Center has done some inventory work on the Craig Mountain Wildlife Management 

Area owned by the Idaho Department of Fish and Game. However, 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 are being planned in the near future. Surveys on Tribal lands in Idaho have 

not yet occurred although funding has been secured to survey Nez Perce Tribal lands 

within S. spaldingii’s habitat in Idaho, Oregon, and southern Washington (A. Sondenaa, 

in litt. 2003). Palouse grasslands have generally been surveyed only in association with 
Draft Recovery Plan for Silene spaldingii ! October 2005 

35 

section 7 consultation projects, although increased attention to Palouse prairie fragments 

is leading to an increase in non-project specific inventory efforts. 

(b) Montana. In Montana, the Montana Natural Heritage Program is conducting 

a status report, visiting all existing populations and searching some suitable habitat on the 

Kootenai National Forest, around The Nature Conservancy’s Dancing Prairie Preserve, 

and in the Niarada area (C. Bjork, private consultant, pers. comm. 2003; Hill and Gray 

2004a). 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 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, in litt. 2004). Funding is being sought to conduct 

further surveys for S. spaldingii on Tribal lands within Montana (U.S. Fish and Wildlife 

Service, in litt. 2004). 

(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 completely inventoried (R. Taylor, in litt. 2003). The WallowaWhitman 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). Funding has recently been secured for inventory work on Nez Perce lands (A. 

Sondenaa, in litt. 2003). 

(d) Washington. In Washington, inventories are being conducted on lands 

owned by the Bureau of Land Management (B. Benner, in litt. 2003; C. Button, in litt. 

2004), at the Fairchild Air Force Base (Caplow 2001), and at Turnbull National Wildlife 

Refuge (Weddell 2002). Swanson Lake Wildlife Area, owned by the State, has been 

partially inventoried and Wawawai Canyon near the Snake River, owned by the 

Washington Department of Natural Resources, has been inventoried (Caplow 2002b). 

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). Funding has recently been secured for inventories on Nez Perce 

Tribal lands in parts of Washington. 

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 (Hill and Gray 2004a). Over 40 percent of 

known S. spaldingii sites are on private land; in general, these private lands have had 
Draft Recovery Plan for Silene spaldingii ! October 2005 

36 

much less inventory effort. The possibility for large populations residing on private 

property can not be overlooked. Several recent land acquisitions in Washington (B. 

Benner, in litt. 2003), 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. In Idaho, 3 populations of Silene spaldingii have 19 monitoring or 

demography transects or plots located either on areas administered by the Bureau of Land 

Management or on lands managed by the Idaho Department of Fish and Game at Craig 

Mountain. Two of these populations, one managed by the State and the other by the 

Bureau of Land Management, have two permanent long-term monitoring plots each that 

have been monitored in 2001, 2002, and 2003 (Lichthardt and Gray 2002). The largest 

population in Idaho, Garden Creek Ranch, has four permanent long-term monitoring 

plots, all on Bureau of Land Management Lands, that were monitored in 2001, 2002, and 

2003 (Lichthardt and Gray 2002), seven permanent demographic belt transects that 

compare a burned and unburned site within the population measured in 2002 and 2003 

(Hill and Weddell 2003; Hill and Gray 2004b), three permanent belt transects that 

monitor nonnative plant invasions (two Centaurea solstitialis sites and one Poa pratensis

site) monitored in 1999 and again in 2003 (Hill and Gray 2000; Hill et al. 2001; Hill and 

Fuchs 2002, 2003; J. Hill, in litt. 2003), and one permanent monitoring transect 

established in 1998 (U.S. Bureau of Land Management 1998). All of the monitoring 

plots and transects at Garden Creek Ranch are on Bureau of Land Management Lands. In 

addition, accurate mapping of seven S. spaldingii locales and invasive nonnative plants 

has been done at Garden Creek Ranch (Hill and Gray 2000; Hill et al. 2001) and a census 

effort was undertaken in establishing the eight permanent long-term monitoring plots for 

the three populations described above (Lichthardt and Gray 2002). At two of the seven 

permanent demographic belt transect sites, trend monitoring by census has been 

conducted for 5 consecutive years (Hill and Gray 2000; Hill et al. 2001; Hill and Fuchs 

2002, 2003). In addition, 107 plots at 32 locales within the Garden Creek Ranch 

population on Bureau of Land Management and Nature Conservancy lands were 

established and monitored in 2001 and 2003 in conjunction with a master’s thesis to 

monitor nonnative plant invasions and fire effects (Menke 2003). 

(b) Montana. In Montana, monitoring occurred at Wild Horse Island from 1986 

to 1992. A demography study has been ongoing at The Nature Conservancy’s Dancing 

Prairie Preserve since 1987 (Lesica 1988c, 1988d, 1997, in litt. 2003) and at the Lost 

Trail National Wildlife Refuge in 2003 (P. Lesica, in litt. 2003). 

(c) Oregon. In Oregon, monitoring plots were established at Clear Lake Ridge 

in 1990, but were not revisited until 2002 (Youtie 1990; Elseroad and Taylor 2002). The 
Draft Recovery Plan for Silene spaldingii ! October 2005 

37 

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). 

(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, 2003). Plots have been 

monitored at Fairchild Air Force Base since 1995 (F. Caplow, in litt. 2003). Demography 

transects were established at Lamona and in the Blue Mountains in 2003 (P. Lesica, in 

litt. 2003). 

3. Additional Sources of Scientific Information on Silene spaldingii 

• Preliminary pollination biology for Silene spaldingii in Montana (Lesica 1988b) 

• Germination requirements and seedling biology of Silene spaldingii (Lesica 1988a, 

1993; A. Raven, pers. comm. 2004) 

• Importance of pollinators for reproduction in Silene spaldingii in Montana (Lesica 

1991, 1993) 

• 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) 

• An investigation of the utility of remote sensing techniques for mapping Centaurea 

solstitialis infestations in Idaho (Lass 1999; Hill 2002a, 2002b) 

• Effects of invasive nonnative plants and fires on Silene spaldingii at Garden Creek 

Ranch, Idaho (Hill and Gray 2000; Hill et al. 2001; Hill and Fuchs 2002, 2003; 

Lichthardt and Gray 2002; Menke 2003; Gray and Lichthardt 2004) 

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 
Draft Recovery Plan for Silene spaldingii ! October 2005 

38 

spaldingii are not sprayed; however, until 2004, surveys for S. spaldingii were not 

conducted prior to spraying (J. White, in litt. 2003). 

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, 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 control of Potentilla 

recta (sulfur cinquefoil) (Lesica and Martin 2003). Annual and sometimes biannual spotspraying from a backpack or ATV (all-terrain vehicle) of Potentilla recta, Hypericum 

perforatum (St. Johnswort), Hieracium pretense (meadow hawkweed), and Centaurea 

maculosa (spotted knapweed) has occurred for the last 9 years (P. Lesica, in litt. 2003). 

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.

2003). 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). 

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 (U.S. Bureau of Land Management 2002). 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 (U.S. Fish and Wildlife Service 2002). The Bureau of 

Land Management’s Cottonwood District 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 (U.S. Fish and Wildlife Service, in litt. 2003). 
Draft Recovery Plan for Silene spaldingii ! October 2005 

39 

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 seed in disturbed areas at two of these locales has been 

done for 4 years at Garden Creek Ranch (Hill and Gray 1999, 2000; Hill et al. 2001; Hill 

and Fuchs 2002, 2003). The Bureau of Land Management’s Cottonwood District 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; Caplow 2001). 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). 

Annual grasses exist near S. spaldingii sites at Crow Creek on the WallowaWhitman 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). Centaurea 

maculosa is being treated along the road to the above S. spaldingii site (J. Hustafa, in litt. 

2004b). 

5. Additional Conservation Actions 

• Silene spaldingii seeds have been collected at one population in Idaho (Garden 

Creek), one population in Montana (Wild Horse Island), two populations in Oregon 

(Clear Lake Ridge and Crow Creek), and one 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, and over 31,000 seeds from Oregon in 

2001. 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). 
Draft Recovery Plan for Silene spaldingii ! October 2005 

40 

• 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) (see Section H-1,“Inventory Efforts”). 

• 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. The first year of this treatment was 2003, with 40.5 hectares (100 acres) 

of Silene spaldingii habitat burned (M. Mantas, in litt. 2003). 

• 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). 

I. BIOLOGICAL CONSTRAINTS 

The long-lived nature of Silene spaldingii, in conjunction with sporadic and rare 

recruitment, delayed maturity, 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). 

Ground disturbing activities including fires, livestock grazing, and off-road 

vehicle use impact Silene spaldingii the most during the flowering and seeding period 

(late July to September) and during seedling 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 (within 1.6 kilometers [1 

mile]) to provide for pollen exchange and enhance gene flow and genetic variability. 
Draft Recovery Plan for Silene spaldingii ! October 2005 

41 

II. Recovery Strategy and Goals 

A. RECOVERY STRATEGY AND RATIONALE 

The fragmentation of Silene spaldingii’s habitat by human related activities has 

reduced the species to a mosaic of small populations (68 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; Karron et al. 1988; Ellstrand 

1992; Ellstrand and Elam 1993). 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). The fragmented 

distribution of small populations further contribute to the positive feedback loop that 

Gilpin and SoulJ (1986) have termed an “extinction vortex.” Such depleted populations, 

and the species that they constitute, are more susceptible to both predictable and 

unexpected genetic, environmental, and demographic vagaries (Frankel and SoulJ 1981; 

Shaffer 1987; Simberloff 1988; Ellstrand 1992; Ellstrand and Elam 1993). 

Because small, fragmented populations with limited gene flow and susceptibility 

to inbreeding face a greater risk of extinction (Frankham 2003), increasing the size and 

connectivity of the larger remaining S. 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 and references therein). Frankham (2003) 

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; Newman and Pilson 1997; Neel and 

Cummings 2003), but also provides the material for future adaptation and evolutionary 

potential, thereby increasing the species’ probability of persistence over the long-term 

(Lande and Barrowclough 1987; Shaffer 1987 and references therein; Simberloff 1988; 

Nunney and Campbell 1993; Neel and Cummings 2003). 

As to how many populations are necessary, if specific genetic data on the 

populations selected for conservation are lacking, a recent evaluation demonstrated that 
Draft Recovery Plan for Silene spaldingii ! October 2005 

42 

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). 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) note 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 potentially exists, to reach the total number of 26 key conservation areas across 

the historical range of S. spaldingii intended to preserve the available genetic variability 

within the species and provide for its long-term persistence. 

 Estimating the 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; Oostermeijer et al. 2003). Detailed 

information on parameters such as recruitment, growth, mortality, and age structure of 

the population are required to model population persistence (Menges 1990; Schemske et 

al. 1995; Lesica 1997), consequently many years of monitoring will be 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 500 

reproductive individuals (summarized in Schonewald-Cox et al. 1983). 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). 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). 

Another study found plants that were primarily outcrossing species were more prone to 

extinction than other selfing species (Lennartsson 2002). 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 (SoulJ and 

Simberloff 1986; Shaffer 1987; Nunney and Campbell 1993; Lande 1995). Researchers 

examining Silene regia found that population size was not the primary influencing factor, 
Draft Recovery Plan for Silene spaldingii ! October 2005 

43 

but that fire management most significantly affected survivability into the future (Menges 

and Dolan 1998). Clearly a population viability analysis is preferable and necessary to 

best estimate the minimum viable population numbers specific to Silene spaldingii. In 

the meantime, we suggest utilizing the standard minimum of 500 reproductive individuals 

until such a population viability analysis can be completed. 

 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), which focuses on the preservation of 

several populations, each supporting a density of at least the minimum viable population 

size, across heterogenous 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 greater8

• Native plants comprise at least 80 percent of the vegetative community 

• Adjacent habitat is available 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 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 interact. 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 plant management, small populations and habitat 

fragmentation, livestock use, wildlife herbivory, fire suppression and increases, habitat 

development, 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. 

 

8

 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. 
Draft Recovery Plan for Silene spaldingii ! October 2005 

44 

spaldingii, and that also address the threats to the species. To accomplish conservation 

and recovery of S. spaldingi 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. 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. Off-road 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 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) assessed the implications of prolonged dormany 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 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 essential 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. 
Draft Recovery Plan for Silene spaldingii ! October 2005 

45 

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 

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, 

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 page 19). 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-six 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 
Draft Recovery Plan for Silene spaldingii ! October 2005 

46 

the Blue Mountain Basins, 6 within the Canyon Grasslands, 8 within the Channeled 

Scablands, 4 within the Intermontane Valleys, and 3 within the Palouse Grasslands. 

The number of 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. 

The validity of preserving the species based on populations composed of at least 500 

reproducing individuals should be verified by the results of a population viability 

analysis that incorporates threats and further genetic and demographic research on 

Silene spaldingii. The analysis should be initiated within 3 years and completed 

within 15 years of the approval of this recovery plan. Once the population viability 

analysis is completed, the recovery criteria listed here will be revisited and the target 

of 500 reproducing individuals per key conservation area may be adjusted, as 

appropriate. 

2. All 26 key conservation areas of Silene spaldingii are composed of at least 80 percent 

native vegetation, 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 (λ ≥ 0) for at least 20 years. 

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, 

overgrazing by 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 0.4 kilometer (0.25 mile) radius of all S. 

spaldingii populations within key conservation areas. 

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 will not 

take place when it may exacerbate invasive nonnative plant populations. 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. 
Draft Recovery Plan for Silene spaldingii ! October 2005 

47 

7. Seed banking occurs at 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. 

8. A post-delisting monitoring program for the species is 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. 
Draft Recovery Plan for Silene spaldingii ! October 2005 

48 

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, or work to create, at least 1 new population and 

key conservation area within the Blue Mountain Basins with over 500 

individuals. 

1.1.3. 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: six key conservation areas). 

1.2.1. Conserve and work to enhance the three Silene spaldingii populations 

within the Canyon Grasslands identified here as potential key conservation 

areas. 

1.2.2. Conduct further surveys to identify at least 3 new populations and 

potential key conservation areas within the Canyon Grasslands with over 

500 individuals. 

1.2.3. Control and manage invasive nonnative plant species specific to the 

Canyon Grasslands. 

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 10 Silene spaldingii

populations within the Channeled Scablands identified here as potential 

key conservation areas. 

1.3.2. Control and manage invasive nonnative plant species specific to the 

Channeled Scablands. 
Draft Recovery Plan for Silene spaldingii ! October 2005 

49 

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 four 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 3 additional potential key 

conservation areas with over 500 individuals. 

1.4.3. 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 two 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. 

1.5.3. Supplement existing populations and conduct a restoration and 

reintroduction program within the Palouse Grasslands to achieve the goal 

of 3 key conservation areas of Silene spaldingii with over 500 individuals. 

1.5.4. 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.

2.3.1. Implement invasive nonnative plant control and management measures at 

all Silene spaldingii sites, taking care not to impact S. spaldingii. 

2.3.2. Incorporate integrated pest management programs into habitat 

management plans for Silene spaldingii at all key conservation areas. 

2.3.3. Conduct invasive nonnative plant control and management measures at all 

key conservation areas and other populations as needed. 

2.3.4. Ensure invasive nonnative plant control and management measures are 

coordinated with appropriate agencies. 

2.3.5. Conduct outreach activities for individuals or organizations that are 

involved in controlling and managing invasive nonnative plants. 

2.3.6. Conduct surveys for Silene spaldingii before invasive nonnative plant 

control measures are implemented. 

2.3.7. Develop and implement guidelines for herbicide applications around 

Silene spaldingii plants. 
Draft Recovery Plan for Silene spaldingii ! October 2005 

50 

2.3.7.1.1. Develop set distances where various herbicide application 

techniques may be used near Silene spaldingii plants. 

2.3.7.1.2. Develop set distances for specific herbicides that may be 

employed near known Silene spaldingii sites. 

2.3.7.1.3. Develop guidelines for the timing of herbicide applications. 

2.3.8. Conduct fire management activities within Silene spaldingii habitat. 

2.3.8.1. Incorporate fire management plans into habitat management 

plans for all Silene spaldingii populations identified as key 

conservation areas on public lands. 

2.3.8.2. Carefully conduct prescribed burns within Silene spaldingii 

habitat. 

2.3.8.2.1. Conduct surveys for Silene spaldingii before 

prescribed burns are implemented. 

2.3.8.2.2. Monitor the effects to Silene spaldingii and its habitat 

from all burns. 

2.3.8.2.3. Do not conduct prescribed burns where invasive 

nonnative plant infestations exist. 

2.3.9. Protect Silene spaldingii sites from development on public and private 

lands. 

2.3.10. Effectively manage livestock grazing in Silene spaldingii habitat. 

2.3.11. Implement effective off-road vehicle use control measures. 

2.3.12. Monitor and manage wildlife populations and associated management 

activities to avoid impacts to Silene spaldingii and its habitat. 

2.4. Monitor population trends and habitat conditions. 

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 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 for creating new populations or 

supplementing existing populations of Silene spaldingii. 

2.5.2.3. Determine the best techniques to restore Silene spaldingii habitat. 
Draft Recovery Plan for Silene spaldingii ! October 2005 

51 

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. 

2.5.8. Conduct research investigating the period seeds may remain viable in the 

soil. 

2.5.9. Conduct further genetic research for Silene spaldingii. 

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 education 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. 

3. Develop a post-delisting monitoring plan. 
Draft Recovery Plan for Silene spaldingii ! October 2005 

52 

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). In addition, genes also vary 

across the larger landscape (Huenneke 1991). 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, 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). 

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 over 500 reproducing individuals within the Blue Mountain

Box 3. Interpretation of Figures 6 through 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. 
Draft Recovery Plan for Silene spaldingii ! October 2005 

53

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

conservation areas within the Blue Mountain Basins physiographic region. 
Draft Recovery Plan for Silene spaldingii ! October 2005 

54 

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 401 individuals, Crow Creek has at least 835 

individuals, Wallowa Lake has at least 506 individuals, and the Zumwalt 

Prairie has at least 1,613 individuals. Furthermore, all four populations 

have other satellite populations nearby (generally within 5 kilometers [3 

miles]) with intact habitat between; Silene spaldingii could be found in 

these interspaces 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 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 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 1 new 

population 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. 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: Potentilla recta (sulfur 
Draft Recovery Plan for Silene spaldingii ! October 2005 

55 

cinquefoil), Centaurea maculosa (spotted knapweed), C. diffusa (diffuse 

knapweed), and C. solstitialis (yellow starthistle). These invasive 

nonnative plant species, and others as they are discovered, should be 

controlled or eliminated within a 0.4 kilometer (0.25 mile) radius of 

Silene spaldingii populations at key conservation areas (see Recovery 

Action 2.3.1). Other invasive nonnative grass species including Poa 

pratensis (Kentucky bluegrass), Bromus tectorum (cheatgrass), and 

Ventenata dubia (ventenata), should be reduced to less than 20 percent 

cover through habitat management programs. 

1.2. Conserve, identify, and expand Silene spaldingii populations and habitat 

within the Canyon Grasslands (goal: six key conservation areas). The 

Canyon Grasslands of Idaho, Oregon, and Washington, with nine Silene 

spaldingii populations, have three potential key conservation areas identified here: 

the Blue Mountain Foothills, Craig Mountain, and Garden Creek (Figure 7). 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 6 populations of S. spaldingii with intact habitat and over 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 three Silene spaldingii populations 

within the Canyon Grasslands identified here as potential key 

conservation areas. Two of these populations already number more than 

500 individuals: the Blue Mountain Foothills has at least 997, and Garden 

Creek has at least 3,987 individuals. Two separate populations comprise the 

Craig Mountain key conservation area as shown in Figure 7: Captain John 

Creek with at least 272 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 Blue Mountains Foothills 

population is managed by the Umatilla National Forest. Craig Mountain is 

managed by the Bureau of Land Management Cottonwood District 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. 
Draft Recovery Plan for Silene spaldingii ! October 2005 

56

Figure 7. The nine known Silene spaldingii populations and three potential key 

conservation areas identified within the Canyon Grasslands physiographic region.
Draft Recovery Plan for Silene spaldingii ! October 2005 

57 

1.2.2. Conduct further surveys to identify at least 3 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 

considered suitable habitat for Silene spaldingii. The Canyon Grasslands are 

extremely steep and difficult to access, which has kept the habitat relatively 

intact and undersurveyed. 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 key 

conservation areas must be established to meet the recovery goal for this 

region. If three new populations cannot be discovered with increased survey 

effort, the establishment of new populations should be considered (see 

Recovery Action 2.5.2). 

1.2.3. Control and manage invasive nonnative plant species specific to the 

Canyon Grasslands. Within the Canyon Grasslands, invasive nonnative 

plants of concern include: Crupina vulgaris (common crupina), Centaurea 

diffusa (diffuse knapweed), Euphorbia esula (leafy spurge), Lepidium 

latifolium (perennial pepperweed), Acroptilon repens (Russian knapweed), 

Onopordum achanthium (Scotch thistle), Centaurea maculosa (spotted 

knapweed), Potentilla recta (sulfur cinquefoil), Linaria (toadflax), and 

Cardaria draba (whitetop). These invasive nonnative plants and others as 

they are discovered should be controlled or eliminated within a 0.4 kilometer 

(0.25 mile) radius 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), Ventenata 

dubia (ventenata), Centaurea solstitialis (yellow starthistle), and Hypericum 

perforatum (St. Johnswort) 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 reduced to 

covers of less than 20 percent through management programs. 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 0.4 kilometer (0.25 

mile). 

1.3. Conserve, identify, and expand Silene spaldingii populations and habitat 

within the Channeled Scablands (goal: eight key conservation areas). The 

Channeled Scablands region of Washington, with 35 Silene spaldingii 

populations, has 10 potential key conservation areas identified here: Coal Creek – 
Draft Recovery Plan for Silene spaldingii ! October 2005 

58 

Lamona, Crab Creek, Fishtrap Lake – Miller Ranch, Rock Creek, Rock Creek 

– Adams County, Rocky Ford, Sprague South, 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 8 populations of S. spaldingii with intact habitat surrounding the 

populations and over 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 10 Silene spaldingii 

populations within the Channeled Scablands identified here as potential 

key conservation areas. Of these 10 potential key conservation areas, only 

the Coal Creek – Lamona site currently has over 500 individuals. To meet 

the recovery goal for this region, at least 7 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 387 individuals, Rock 

Creek has at least 173 individuals, Rock Creek – Adams County has at least 

145 individuals, Rocky Ford has over 300 individuals, Sprague South has 

over 200 individuals, Swanson Lake has over 487 individuals at 1 population 

and over 220 at another, the Telford area has over 400 individuals, and Twin 

Lakes has 3 populations with over 100 individuals, one of these with over 

271 individuals. Two of these potential key conservation areas, Swanson 

Lake and Twin Lakes, include 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. Rock Creek and Sprague South both have 

satellite populations that are within 3 miles of their current geographic 

extent, which with further survey effort could yield one larger population. 

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, Rock Creek – Adams County, Rocky Ford, 

and Telford key conservation areas are all managed by the Bureau of Land 

Management Spokane District. Rock Creek, Sprague South, and 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.
Draft Recovery Plan for Silene spaldingii ! October 2005 

59

Figure 8. The 35 known Silene spaldingii populations and 10 potential key conservation 

areas identified within the Channeled Scablands physiographic region. 
Draft Recovery Plan for Silene spaldingii ! October 2005 

60 

1.3.2. 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), Linaria (toadflax), and Centaurea solstitialis (yellow 

starthistle). These invasive nonnative plants and others as they are 

discovered should be controlled or eliminated within a 0.4 kilometer (0.25 

mile) radius 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 reduced to covers of less than 20 percent through 

management programs. 

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 nine Silene spaldingii populations, have 

five potential key conservation areas identified: Dancing Prairie, Lost Trail, 

Sullivan Hill, Tobacco Plains, and Wild Horse Island (Figure 9). Only one of 

these potential key conservation sites has a population with over 500 individuals, 

Dancing Prairie. Surveys and supplementation of already existing populations 

may be necessary within the Intermontane Valleys to achieve the recovery goal of 

4 populations with over 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 four 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. 

Lost Trail is separated into 2 populations, 1 with 50 to 100 individuals, and 1 

with 150 to 200 individuals; Sullivan Hill has at least 67 individuals; the 

Tobacco Plains have at least 223 individuals; and Wild Horse Island has at 

least 250 individuals. The Tobacco Plains and Dancing Prairie are within 3 

miles of one another and could be part of one larger population/key 

conservation area if further surveys identify additional individuals of S. 

spaldingii in the interspaces. The Dancing Prairie key conservation area is 

composed of lands managed by The Nature Conservancy on its Dancing 

Prairie Preserve
Draft Recovery Plan for Silene spaldingii ! October 2005 

61

Figure 9. The nine Silene spaldingii populations and five potential key conservation 

areas identified within the Intermontane Valleys physiographic region. 
Draft Recovery Plan for Silene spaldingii ! October 2005 

62 

as well as private landowners. Lost Trail includes lands managed by the U.S. 

Fish and Wildlife Service at the Lost Trail National Wildlife Refuge as well 

as adjacent State lands. Sullivan Hill is on Tribal lands managed by the 

Confederated Salish and Kootenai Tribes. Wild Horse Island is managed by 

Montana Fish, Wildlife, and Parks, and the Tobacco Plains key conservation 

area occurs entirely on private lands and spans the border of the United States 

and Canada. 

1.4.2. Conduct further surveys or work to supplement existing populations 

within the Intermontane Valleys to achieve 3 additional key 

conservation areas with over 500 individuals. The Dancing Prairie site 

already meets the criteria for a key conservation area. Three 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 reside. If 3 new populations with over 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). 

1.4.3. 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 within a 0.4 kilometer (0.25 

mile) radius 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 reduced to covers of less than 20 percent 

through management programs. 

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 18 Silene spaldingii 

populations, have 2 potential key conservation areas identified, the Kramer 

Palouse Natural Area and the Pitt Cemetery (Figure 10). Both of these sites are 

small (under 16 hectares [40 acres]) and have fewer than 500 individuals. Of the
Draft Recovery Plan for Silene spaldingii ! October 2005 

63

Figure 10. The 18 Silene spaldingii populations and 2 potential key conservation 

areas within the Palouse Grasslands physiographic region.
Draft Recovery Plan for Silene spaldingii ! October 2005 

64 

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 3 

populations with over 500 reproducing individuals. 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 two 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 2 miles of another population with 

11 individuals. The Pitt Cemetery has at least 62 S. spaldingii individuals. 

The Kramer Palouse Natural Area is managed by Washington State 

University and the Pitt Cemetery 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. 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 3 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/or restoration and 

reintroduction to establish additional key conservation areas. If intact 

habitat exists or if adjacent habitat can 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 over 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 
Draft Recovery Plan for Silene spaldingii ! October 2005 

65 

conserved and subsequently planted with nearby genetic material from S. 

spaldingii. 

1.5.4. 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 within a 

0.4 kilometer (0.25 mile) radius 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 Palouse 

Grassland sites and so would be extremely expensive and difficult to control. 

Instead, these invasive nonnative plant species should be reduced to covers 

of less than 20 percent through management programs 

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 essential (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. Key 

conservation areas should be prioritized, however, the threats addressed through 

habitat management and recovery actions should be addressed at all known 

populations of S. spaldingii when feasible. 

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 Upper Columbia Salmon 

Clearwater District 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 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; 
Draft Recovery Plan for Silene spaldingii ! October 2005 

66 

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 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 through integrated pest management 

programs, changes in the fire regime, land conversions, 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, 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. 

2.3.1. Implement invasive nonnative plant control and management 

measures 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 
Draft Recovery Plan for Silene spaldingii ! October 2005 

67 

enact control measures when economic and/or ecological values are 

affected should be incorporated into S. spaldingii habitat management 

plans.

2.3.1.1. Incorporate integrated pest management programs into habitat 

management plans for Silene spaldingii at all key conservation 

areas. 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 plans 

should seek to control nonnative plant invasions while maintaining 

or restoring the native plant community, not just S. spaldingii. 

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). Integrated pest management strategies 

should identify all control methods available such as prevention, 

manual control, 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, 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. 
Draft Recovery Plan for Silene spaldingii ! October 2005 

68 

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 (U.S. Fish and Wildlife 

Service, in litt. 2004). Outreach is needed to inform invasive 

nonnative plant management agencies such as Weed Management 

Areas, County Weed Boards, and programs for 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. 

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 5 miles (8 kilometers) an hour 

to minimize herbicide drift. Aerial spraying (from airplanes or 

helicopters) should not occur within 1,000 feet (305 meters) of 

known S. spaldingii plants; boom spraying should not occur 

within 50 feet (15 meters), and wiping or wicking should be the 

only herbicide application technique employed when within 50 
Draft Recovery Plan for Silene spaldingii ! October 2005 

69 

feet (15 meters). 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 50 feet 

(15 meters) 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 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; Tisdale 1986b). 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. 
Draft Recovery Plan for Silene spaldingii ! October 2005 

70 

2.3.2.1. Incorporate fire management plans into habitat management 

plans for all Silene spaldingii populations identified as key 

conservation areas on public lands. 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 and 

fewer problems with tree encroachment. 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 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 considered as a management 

tool for increasing Silene spaldingii in areas where Festuca scabrella

(rough fescue) is a dominant species (Lesica 1999). Additional 

research is needed to determine if prescribed burning will benefit S. 

spaldingii in other areas. Prescribed burning should be carefully 

employed across S. spaldingii’s range. 

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 studies should be done for 3 years 

prior to burning, whenever possible. Post-fire monitoring 

should be done consecutively for 3 years, every 5 years, for a 

monitoring period of at least 15 years after a fire. This 
Draft Recovery Plan for Silene spaldingii ! October 2005 

71 

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. Fire may exacerbate nonnative plant 

invasions (Christensen and Burrows 1986; Hobbs and 

Huenneke 1992; Lesica and Martin 2003). In areas where 

invasive nonnative plants are present, 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. 

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. Sites on State lands should be protected 

from development through habitat management plans and by needed State 

designations. Consideration of sales to conservation entities may also be 

considered. Populations of S. spaldingii on private land should be 

protected by conservation easements, consideration of deed restrictions, or 

possibly direct acquisition from willing landowners. Working through 

appropriate State, local, or County agencies, voluntary cooperation 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) 

(Oregon Natural Heritage Program 2003; Hill and Gray 2004). 

2.3.4. Effectively manage livestock grazing in Silene spaldingii 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. 

Monitoring of all known S. spaldingii sites within grazing allotments 

should be conducted on a regular basis, and if populations decline grazing 

practices should be amended. Effective grazing management may include 

the construction and maintenance of fencing, moving watering troughs, 
Draft Recovery Plan for Silene spaldingii ! October 2005 

72 

allowing for rest years, and revising allotment plans, grazing schedules, 

and stocking levels to maintain S. spaldingii 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. Heavy grazing 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. 

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. 

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. 

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. 

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, 

grazing, 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 
Draft Recovery Plan for Silene spaldingii ! October 2005 

73 

the long-lived nature of the plant and its prolonged dormancy, to 

adequately assess trends monitoring should occur consecutively for 3 or 

more years every 5 to 20 years (Lesica and Steele 1994). 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. Because of the difficulties prolonged dormancy 

presents for monitoring, either repeated measures analysis (Lesica and 

Steele 1994; Lesica and Steele 1996; Lesica and Steele 1997) or markrecapture methods (Alexander et al. 1997; Shefferson et al. 2001) should 

be utilized. This standardized trend monitoring procedure should identify 

at what time of the year monitoring should occur and standardize age 

classes. 

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), and 

are necessary for conducting population viability analyses (see Recovery 

Action 2.5.1). 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. 

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 sitespecific fire management plans. The same should be done in association 

with the incursion of invasive nonnative plants. 

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. 

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 
Draft Recovery Plan for Silene spaldingii ! October 2005 

74 

been dormant at the time they were last surveyed and have since 

reappeared, or if the species should be considered extirpated from these 

sites. 

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, 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 and demographic 

studies, to determine the long-term population viability of Silene 

spaldingii. 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). 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) should also be evaluated. A population 

viability analysis will also assist in determining whether the current goal 

of 500 reproducing individuals in a potential key conservation area 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), making human intervention 

necessary to preserve smaller populations. Preliminary studies looking at 

seedling growth indicate that growing S. spaldingii in cultivation is a 

possibility (Lesica 1988a, 1993; Hill and Gray 2000, 2004a; A. Brusven, 

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. 
Draft Recovery Plan for Silene spaldingii ! October 2005 

75 

2.5.2.1. Utilize existing 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 and reintroduction 

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 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. 

2.5.2.3. 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. 

Methods 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 
Draft Recovery Plan for Silene spaldingii ! October 2005 

76 

invasive nonnative plants are 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. 

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, impact Silene 

spaldingii, its habitat, and nonnative plant invasions. Aside from livestock 

grazing, 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 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 to 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 historic 

fire season? Since some research on fire effects has already taken place 
Draft Recovery Plan for Silene spaldingii ! October 2005 

77 

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, 1993; Lesica and Heidel 1996), 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 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. 

Nighttime pollination, found to be important in another rare Silene, should 

be investigated (Kephart 2003). The effects of threats including livestock 

grazing 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 investigating the period seeds may remain viable in 

the soil. 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 
Draft Recovery Plan for Silene spaldingii ! October 2005 

78 

production to fire or grazing will dramatically reduce the amount of seed 

available for recruitment. 

2.5.9. Conduct further genetic research for Silene spaldingii. Baldwin and 

Brunsfeld’s (1995) genetic study was only a preliminary genetic study; 

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). 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). 

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 

and should be incorporated with the population viability analysis 

identified in Recovery Action 2.5.1 above. 

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. 

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 may 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 
Draft Recovery Plan for Silene spaldingii ! October 2005 

79 

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 40 percent of the known 

populations of Silene spaldingii are on lands not managed by Federal, Tribal, or 

State entities (Hill and Gray 2004). 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 7 

known populations with over 500 individuals is currently unprotected on private 

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 (Montana Natural 

Heritage Program 2003). The Zumwalt Prairie Preserve in Oregon and the 

Garden Creek Ranch in Idaho also have large populations of S. spaldingii

(Idaho Conservation Data Center 2003, Oregon Natural Heritage Program 

2003). 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. 
Draft Recovery Plan for Silene spaldingii ! October 2005 

80 

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 on private lands include the U.S. 

Fish and Wildlife Service’s Partners for Fish and Wildlife Program, 

Private Stewardship Grants, and Landowner Incentive Program; and the 

Natural Resource Conservation Service’s Environmental Quality 

Incentives Program, Wildlife Habitat Incentives Program, Conservation 

Reserve Program, and Grassland Reserve Program. 

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 invasive nonnative plant control related groups 

(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. 

2.8. Pursue land and species designations that will help facilitate conservation 

of Silene spaldingii. Federal agencies should consider designating essential 

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. 
Draft Recovery Plan for Silene spaldingii ! October 2005 

81 

2.9. Establish propagule banks, including a long-term seed storage facility for 

Silene spaldingii. Silene spaldingii seeds have been collected from only five 

populations, all of which are relatively large. Seeds of S. spaldingii should be 

collected according to currently accepted protocol from all populations not 

identified as key conservation areas, 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. 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. 

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. 
Draft Recovery Plan for Silene spaldingii ! October 2005 

82 

 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 35 year timeframe to recovery and delisting of the species. Because Silene 

spaldingii is a long-lived perennial species and annual counts vary significantly in 

response to climatic events, a minimum of 20 years of monitoring is needed to determine 

long-term population trends. The earliest 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. 
Draft Recovery Plan for Silene spaldingii ! October 2005 

83 

Key to Responsible Parties: 

BBG Berry Botanic Garden 

BLM Bureau of Land Management 

CSKT Confederated Salish and Kootenai Tribes 

CBLM Cottonwood District 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 

LTNWR Lost Trail National Wildlife Refuge 

MBLM Montana Bureau of Land Management 

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 
84

Implementation Schedule for the Silene spaldingii Draft Recovery Plan 

Cost Estimates ($1,000) Priority 

Number 

Action 

Number 

Action Description Action 

Duration 

(years) 

Responsible 

Parties Total 

CostH

FY 

2005 

FY 

2006 

FY 

2007 

FY 

2008 

FY 

2009 

1 1.1.1 

Conserve and work to enhance four Silene spaldingiipopulations within the Blue Mountain Basins identified here as key conservation areas.

Ongoing 

EDU, NRCS, 

OCJG, PVT, 

SWCD, 

USFWS*, 

WWNF, ZPP 

1 1.2.1 

Conserve and work to enhance three Silene spaldingiipopulations within the Canyon Grasslands identified here as key conservation areas. 

Ongoing 

CBLM, 

CMWMA, 

EDU, GKR, 

NPT, UNF, 

USFWS*, 

WWNF 

1 1.3.1 

Conserve, survey, and work to enhance 10 Silene spaldingii

populations within the Channeled Scablands identified here as key conservation areas. 

Ongoing 

NRCS, PVT, 

SBLM*, 

SLWA, SWCD, 

USFWS 

1 1.4.1 

Conserve and work to enhance four Silene spaldingiipopulations within the Intermontane Valleys identified here as key conservation areas. 

Ongoing 

CSKT, DPP, 

EDU, LTNWR, 

PVT, ST, 

USFWS*, 

WHISP 

1 1.5.1 

Conserve and work to enhance two Silene spaldingiipopulations within the Palouse Grasslands identified here as a key conservation areas. 

Ongoing 

EDU, NRCS, 

PVT, SWCD, 

USFWS*, WSU
85

Implementation Schedule for the Silene spaldingii Draft Recovery Plan (continued)

Priority Cost Estimates ($1,000) 

Number 

Action Number Action Description 

Action 

Duration 

(years) 

Responsible 

Parties Total 

CostH

FY 

2005 

FY 

2006 

FY 

2007 

FY 

2008 

FY 

2009 C

1 1.5.3 

Supplement existing populations and conduct a restoration and reintroduction program within the Palouse Grasslands to create 3 new populations and key conservation areas of Silene spaldingii with over 500 individuals. 

Ongoing 

CBLM, EDU, 

NRCS, PVT, 

SBLM, ST, 

SWCD, 

USFWS*, WSU

S2

1 2.10 

Secure funding for implementation or recovery tasks. 

Continual All 

Ca

1 2.2 

Develop Silene spaldingii

specific 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 

465 77.5 77.5 77.5 77.5 77.5 

$kppc

1 2.3.3 

Protect Silene spaldingii sites 

from development on public and private lands. 

Continual All 216 6 6 6 6 6 $

r

1 2.6.4 Protect newly discovered Silene spaldingii populations. Continual All C

a

1 2.7.1 

Conduct conservation actions on lands owned by The Nature Conservancy. 

Ongoing TNC*, USFWS

Ca
86

Implementation Schedule for the Silene spaldingii Draft Recovery Plan (continued)

Priority Cost Estimates ($1,000) 

Number 

Action Number Action Description 

Action 

Duration 

(years) 

Responsible 

Parties Total 

CostH

FY 

2005 

FY 

2006 

FY 

2007 

FY 

2008 

FY 

2009 

1 2.7.2 

Conservation activities on other private lands. Continual All 

2 1.1.2 

Conduct further surveys or work to create 1 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 1.1.3 

Control and manage invasive nonnative plant species specific to the Blue Mountain Basins. 

Ongoing 

OCJG, PVT, 

USFWS, 

VBLM, WMA, 

WWNF*, ZPP 

52.5 1.5 1.5 1.5 1.5 1.5 

2 1.2.2 

Conduct further surveys or work to create 3 new populations and key conservation areas within the Canyon Grasslands with over 500 individuals. 

Ongoing 

CBLM, 

CMWMA, 

EDU, GKR, 

NPT, PVT, 

SBLM, ST, 

UNF, USFWS*, 

VBLM, WWNF

2 1.2.3 

Control and manage invasive nonnative plant species specific to the Canyon Grasslands. Ongoing 

CBLM, 

CMWMA, 

GKR, NPT, 

PVT, ST, UNF, 

USFWS, 

WMA*, 

WWNF 

52.5 1.5 1.5 1.5 1.5 1.5 
87

Implementation Schedule for the Silene spaldingii Draft Recovery Plan (continued) 

Cost Estimates ($1,000) Priority 

Number 

Action 

Number 

Action Description Action 

Duration 

(years) 

Responsible 

Parties Total 

CostH

FY 

2005 

FY 

2006 

FY 

2007 

FY 

2008 

FY 

2009 

2 1.3.2 

Control and manage invasive nonnative plant species specific to the Channeled Scablands. Ongoing 

FAFB, PVT, 

SBLM*, SLWA, 

TNWR, USFWS, 

WMA 

52.5 1.5 1.5 1.5 1.5 1.5 

2 1.4.2 

Conduct further surveys or work to supplement existing populations within the Intermontane Valleys to establish 3 additional populations and key conservation areas with over 500 individuals. 

Ongoing 

CSKT, EDU, FS, 

LTNWR, 

MBLM, NRCS, 

PVT, ST, 

SWCD, 

USFWS* 

2 1.4.3 

Control and manage invasive nonnative plant species specific to the Intermontane Valleys. Ongoing 

CSKT, DPP, FS, 

LTNWR, 

MBLM, PVT, 

ST, USFWS*, 

WHISP, WMA 

52.5 1.5 1.5 1.5 1.5 1.5 

2 1.5.4 

Control and manage invasive nonnative plant species specific to the Palouse Grasslands. Ongoing 

CBLM, PVT, 

SBLM, ST, 

USFWS*, WMA, 

WSU 

17.5 0.5 0.5 0.5 0.5 0.5 

2 2.3.1.5 

Conduct surveys for Silene 

spaldingii before invasive 

nonnative plant control measures are implemented. 

Ongoing All 630 18 18 18 18 18 
88

Implementation Schedule for the Silene spaldingii Draft Recovery Plan (continued) 

Cost Estimates ($1,000) Priority 

Number 

Action 

Number 

Action Description Action 

Duration 

(years) 

Responsible 

Parties 

Total 

CostH

FY 

2005 

FY 

2006 

FY 

2007 

FY 

2008 

FY 

2009 

2 2.3.2.1 

Incorporate fire management plans into habitat management plans for all Silene spaldingii

populations identified as key conservation areas on public lands. 

6 Same as Action 2.2 

2 2.3.2.2.1 

Conduct surveys for Silene spaldingii before prescribed 

burns are implemented. Ongoing All 630 18 18 18 18 18 

2 2.3.2.2.3 

Do not conduct prescribed burns where invasive nonnative plant infestations exist. Ongoing All 

2 2.3.4 

Effectively manage livestock grazing in Silene spaldingiihabitat. Ongoing All 455 13 13 13 13 13 

2 2.3.5 

Implement effective off-road vehicle use control measures. Continual All 175 5 5 5 5 5 

2 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 

2 2.5.2.3 

Determine the best techniques to restore Silene spaldingii

habitat. Continual 

BLM, DOD, 

EDU, FS, ST, T, 

TNC, USFWS*

175 5 5 5 5 5 
89

Implementation Schedule for the Silene spaldingii Draft Recovery Plan (continued) 

Cost Estimates ($1,000) Priority 

Number 

Action 

Number 

Action Description Action 

Duration 

(years) 

Responsible 

Parties 

Total 

CostH

FY 

2005 

FY 

2006 

FY 

2007 

FY 

2008 

FY 

2009 

2 2.9 

Establish propagule banks, including a long-term seed storage facility for Silene spaldingii. Ongoing All, BBG* 35 1 1 1 1 1 

3 1.5.2 

Conduct a study identifying intact habitat within the Palouse Grasslands where Silene spaldingii may occur. 

5 

CBLM, EDU, 

PVT, SBLM, ST, 

USFWS*, WSU

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. 

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* 35 1 1 1 1 1 
90

Implementation Schedule for the Silene spaldingii Draft Recovery Plan (continued) 

Cost Estimates ($1,000) Priority 

Number 

Action 

Number 

Action Description Action 

Duration 

(years) 

Responsible 

Parties 

Total 

CostH

FY 

2005 

FY 

2006 

FY 

2007 

FY 

2008 

FY 

2009 

3 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 

3 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 

3 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 

3 2.3.2.2.2 

Monitor the effects to Silene 

spaldingii and its habitat from all 

burns. 

Ongoing All 350 10 10 10 10 10 

3 2.3.6 

Monitor and manage wildlife populations and associated management activities to avoid impacts to Silene spaldingii and 

its habitat. 

Continual BLM, FS, ST*, T 70 2 2 2 2 2 

3 2.4.1 

Monitor Silene spaldingii

populations at key conservation areas periodically to determine population trends. 

Continual Same as Action 2.2 1,628 46.5 46.5 46.5 46.5 46.5 
91

Implementation Schedule for the Silene spaldingii Draft Recovery Plan (continued) 

Cost Estimates ($1,000) Priority 

Number 

Action 

Number 

Action Description Action 

Duration 

(years) 

Responsible 

Parties 

Total 

CostH

FY 

2005 

FY 

2006 

FY 

2007 

FY 

2008 

FY 

2009 

3 2.4.2 

Conduct demographic monitoring across the range of Silene 

spaldingii. 

Continual Same as Action 2.2 525 15 15 15 15 15 

3 2.4.3 

Monitor and evaluate the response of Silene spaldingii to fire and 

invasive nonnative plants. Ongoing All 

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 525 15 15 15 15 15 
92

. 

Implementation Schedule for the Silene spaldingii Draft Recovery Plan (continued) 

Cost Estimates ($1,000) Priority 

Number 

Action 

Number 

Action Description Action 

Duration 

(years) 

Responsible 

Parties 

Total 

CostH

FY 

2005 

FY 

2006 

FY 

2007 

FY 

2008 

FY 

2009 

3 2.5.3 

Conduct research essential to controlling and managing invasive nonnative plants within Silene spaldingii habitat.

Continual 

BLM, DOD, 

EDU, FS, ST, T, 

TNC, USFWS*

175 5 5 5 5 5 

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 2 2 2 

3 2.5.8 

Conduct research investigating the period seeds may remain viable in the soil. 

Depends 

on 

longevity 

BLM, DOD, 

EDU, FS, ST, T, 

TNC, USFWS*

To be 

determined 1 1 1 1 1 

3 2.5.9 

Conduct further genetic research for Silene spaldingii. 5 

BLM, DOD, 

EDU, FS, ST, T, 

TNC, USFWS*

100 20 20 20 20 20 
93

Implementation Schedule for the Silene spaldingii Draft Recovery Plan (continued) 

Cost Estimates ($1,000) Priority 

Number 

Action 

Number 

Action Description Action 

Duration 

(years) 

Responsible 

Parties 

Total 

CostH

FY 

2005 

FY 

2006 

FY 

2007 

FY 

2008 

FY 

2009 

3 2.6.1 

Conduct surveys on Federal lands for Silene spaldingii. Ongoing BLM*, DOD, FS, USFWS 630 18 18 18 18 18 

3 2.6.2 

Conduct surveys on State and Tribal lands, especially where activities may affect Silene 

spaldingii habitat. 

Ongoing HP, ST, T, USFWS 210 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 210 6 6 6 6 6 

3 2.7.3 

Conduct outreach and education with the public regarding Silene 

spaldingii's plight and its 

conservation. 

Continual All 280 8 8 8 8 8 

3 2.8 

Pursue land and species designations that will help facilitate conservation of Silene 

spaldingii. 

Continual All 35 1 1 1 1 1 

3 2.11 Validate and revise recovery objectives. Continual All, USFWS* 175 3 3.0 

Develop a post-delisting monitoring plan. 1 year All, USFWS* 10 

Total estimated cost for recovery 8,601.5 345.5 353.5 353.5 352.5 344.5..

 HAll ongoing and continual total costs based upon a 35 year time frame; when the species may potentially be recovered 
Draft Recovery Plan for Silene spaldingii ! October 2005 

94 

V. Literature Cited 

Alexander, H. M., N.A. Slade, and W.D. Kettle. 1997. Application of markrecapture models to estimation of the population size of plants. Ecology 

78:1230-1237. 

Alt, D.D. and D.W. Hyndman. 1986. Roadside geology of Montana. Mountain 

Press Publishing Company, Missoula, Montana. 427 pp. 

Alt, D.D. and D.W. Hyndman. 1989. Roadside geology of Idaho. Mountain 

Press Publishing Company, Missoula, Montana. 394 pp. 

Baldwin, C.T. and S.J. Brunsfeld. 1995. Preliminary genetic analysis of Silene 

spaldingii (Spalding’s catchfly), a candidate threatened species. Wildland 

Plant Ecogenetics Cooperative, University of Idaho, in cooperation with 

Montana Natural Heritage Program, Moscow, Idaho. 23 pp. 

Barrett, S.C.H. and J.R. Kohn. 1991. Genetic and evolutionary consequences of 

small population size in plants: Implication for conservation. Pages 1-30 

in D.A. Falk and K.E. Holsinger (editors), Genetics and conservation of 

rare plants. Oxford University Press, Oxford, United Kingdom. 

Biodiversity Legal Foundation, Montana Native Plant Society, Washington 

Native Plant Society, and P. Lesica. 1995. Petition to list Spalding’s 

catchfly (Silene spaldingii) as threatened or endangered under the 

Endangered Species Act. 25 pp. 

Bock, C.E., J.H. Bock, and H.M. Smith. 1993. Proposal for a system of Federal 

livestock exclosures on public rangelands in the Western United States. 

Conservation Biology 7:731-733. 

Boutin, C. and B. Jobin. 1998. Intensity of agricultural practices and effect of 

adjacent habitats. Ecological Applications 8:544-557. 

British Columbia Conservation Data Centre. 2004. Element occurrence records 

for Silene Spaldingii, includes the limited use agreements for digital data. 

6 pp. 

Callihan, R. C. and T. M. Miller. 1997. A pictorial guide to Idaho’s noxious 

weeds. Pages 58-59 in Weed Diagnostic Laboratory, Department of Plant, 

Soil, and Entomological Sciences, College of Agricultures, Agricultural 

Communications Center, University of Idaho, Moscow, Idaho. 
Draft Recovery Plan for Silene spaldingii ! October 2005 

95 

Caplow, F. 2001. Annual report for Spalding's Catchfly (Silene spaldingii) on 

Fairchild Air Force Base, Washington. Washington State Department of 

Natural Resources, Natural Heritage Program, Olympia, Washington. 11 

pp. 

Caplow, F. 2002a. Annual report for Spalding’s catchfly (Silene spaldingii) on 

Fairchild AFB, Washington. Washington Natural Heritage Program. 11 

pp. 

Caplow, F. 2002b. Silene spaldingii Wats. (Spalding's catchfly) field inventory 

and management recommendations. Washington State Department of 

Natural Resources, Natural Heritage Program, Olympia, Washington. 6 

pp. 

Christensen, P.E. and N.D. Burrows. 1986. Fire: An old tool with a new use. 

Pages 57-66 in R.H. Groves, and J.J. Burdon (editors), Ecology of 

biological invasions: An Australian perspective. Australian Academy of 

Science, Canberra, Australia. 

Conner, R., A. Seidl, L. VanTassel, and N. Wilkins. 2001. United States 

grasslands and related resources: An economic and biological trends 

assessment. Available online at 

<http://landinfo.tamu.edu/presentations/chap1_high.pdf>. Accessed 1 

August 2001. 

Crone, E. E. 2001. Is survivorship a better fitness surrogate than fecundity? 

Evolution 55:2611-2614. 

D’Antonio, C.M. and P.M. Vitousek. 1992. Biological invasions by exotic 

grasses, the grass/fire cycle, and global change. Annual Review of 

Ecological Systems 23:63-87. 

Danly, L. 1999. Reports on bio-control insect releases. Craig Mountain, Idaho. 

Bureau of Land Management, Cottonwood, Idaho. 

Daubenmire, R. 1942. An ecological study of the vegetation of southeastern 

Washington and adjacent Idaho. Ecological Monographs 12:53-79. 

Daubenmire, R. 1968. Soil moisture in relation to vegetation distribution in the 

mountains of northern Idaho. Ecology 49:431-438. 

Daubenmire, R. 1970. Steppe vegetation of Washington. Technical Bulletin 62. 

Washington State University, Washington Agricultural Experiment 

Station, College of Agriculture, Pullman, Washington. 131 pp. 
Draft Recovery Plan for Silene spaldingii ! October 2005 

96 

Dolan, R.W. 1994. Patterns of isozyme variation in relation to population size, 

isolation, and phytogeographic history in royal catchfly (Silene regia; 

Caryophyllaceae). American Journal of Botany 81:965-972. 

Douglas, G.W., D.V. Meidinger, and J.L. Penny. 2002. Silene spaldingii. In Rare 

native vascular plants of British Columbia, 2nd edition. British Columbia. 

Ministry of. Sustainable Resource. Management and Water Land and Air 

Protection and British .Colombia. Ministry. Forestry, Victoria, British 

Columbia. 359 pp. 

Dukes, J.S. and H.A. Mooney. 2003. Disruption of ecosystem processes in 

western North America by invasive species. In Bradshaw, P.A. Marquet, 

H.A. Mooney (editors), How landscapes change: Human disturbance and 

ecosystem disruptions in the Americas, series: Ecological studies Vol 

162. G.A.. 66 pp. <http://www.springeronline.com/sgw/cda/front 

page/0,10735,4-102-22-2135615-0,00.html?c>. Accessed 26 March 

2004. 

Ellstrand, N.C. 1992. Gene flow by pollen: implications for plant conservation 

genetics. Oikos 63:77-86. 

Ellstrand, N.C. and D.R Elam. 1993. Population genetic consequences of small 

population size: Implications for plant conservation. Annual Review of 

Ecology and Systematics 24:217-242. 

Elseroad, A. and R. Taylor. 2002. Prescribed burning for Silene spaldingii at 

Clear Lake Ridge Preserve. The Nature Conservancy of Oregon, 

Enterprise, Oregon. 5 pp. 

Ertter, B. and R. Moseley. 1992. Floristic regions of Idaho. Journal of the Idaho 

Academy of Science 28:57-70. 

Farmer, A.M. 1993. The effects of dust on vegetation – A review. 

Environmental Pollution 79:63-75. 

Fenster, C.B. 1991. Gene flow in Chamaecrista fasciculata (Leguminosae). 

Evolution 45:410-422. 

Fleischner, T.L. 1994. Ecological costs of livestock grazing in western North 

America. Conservation Biology 8:629-644. 

Frankel, O.H., and M.E. SoulJ. 1981. Conservation and evolution. Cambridge 

University Press, Cambridge, United Kingdom. 

Frankham, R. 2003. Genetics and conservation biology. Comptes Rendus 

Biologies 326:S22-S29. 
Draft Recovery Plan for Silene spaldingii ! October 2005 

97 

Franklin, J.F. and C.T. Dyrness. 1988. Natural vegetation of Oregon and 

Washington. Oregon State University Press, Corvallis, Oregon. 

Gamon, J. 1991. Report on the status of Silene spaldingii Wats. in Washington. 

Washington State Department of Natural Resources. Washington Natural 

Heritage Program, Olympia, Washington. 53 pp. 

Gilpin, M.E., and M.E. SoulJ. 1986. Minimum viable populations: processes of 

species extinction. Pages 19-34 in M.E. SoulJ (editor). Conservation 

biology: the science of scarcity and diversity. Sinauer Associates, 

Sunderland, Massachusetts. 584 pp. 

Given, D.R. 1994. How plants become threatened or extinct. Pages 13 – 36 in

Principles and practice of plant conservation. Timber Press, Portland, 

Oregon. 

Gray, K. and J.Lichthardt. 2004. Spalding’s catchfly (Silene spaldingii) 

monitoring, Craig Mountain, Idaho, second year results. Idaho 

Conservation Data Center, Idaho Department of Fish and Game, P.O. Box 

25, Boise, Idaho. 27 pp. 

Hanski, I., A. Moilanen, and M. Gyllenberg. 1996. Minimum viable 

metapopulation size. American Naturalist 147:527-541. 

Harris, J.G., and M.W. Harris. 1994. Plant Identification Terminology: an 

illustrated glossary – 2nd Edition. Spring Lake Publishing, Payson, Utah. 

206 pp. 

Harrison, R.D., N.J. Chatterton, R.J. Page, M. Curto, K.H. Asay, K.B. Jensen, 

and W.H. Horton. 1996. Competition, biodiversity, invasion, and wildlife 

use of selected introduced grasses in the Columbia and Great basins. Utah 

Agricultural Experiment Station, Logan, Utah. Available online at 

<http://www.agx.usu.edu/agx/ResearchReports/USDAREPORT/toc.html> 

Accessed 11 November 2003. 

Heidel, B. 1979. Silene spaldingii. Pages 67-69 in Endangered and threatened 

plants in the Northern Idaho BLM District. U.S. Bureau of Land 

Management. Unpublished report. 

Heidel, B. 1995. Preliminary status report for Silene spaldingii (Spalding’s 

catchfly), a candidate threatened species. Montana Natural Heritage 

Program, Helena, Montana. 11 pp.
Draft Recovery Plan for Silene spaldingii ! October 2005 

98 

Hill, J.L. 1998. Garden Creek Ranch cooperative resource management plan for 

1998-2002. Section A - Aggressive Nonnative Plants. Draft, Unpublished 

report for The Nature Conservancy of Idaho and Bureau of Land 

Management, Cottonwood Resource Area, Cottonwood, Idaho. 16 pp. 

Hill, J.L. 2002a. QuickBird Satellite Imagery for detection of yellow starthistle 

at the Garden Creek Ranch. Unpublished report on file at: The Nature 

Conservancy Field Office, Sun Valley, Idaho. 33 pp. 

Hill, J. L. 2002b. Ground-truthing of 1998 tri-state hyperspectral imagery for 

detection of yellow starthistle at the Garden Creek Ranch. Unpublished 

report on file at The Nature Conservancy of Idaho Field Office, Sun 

Valley, Idaho. 14 pp. 

 

Hill, J.L. and S.J. Fuchs. 2002. Special Ecological Areas Pilot Study at the 

Garden Creek Ranch, Craig Mountain, Idaho. Unpublished report on file 

at: The Nature Conservancy of Idaho Field Office, Sun Valley, Idaho. 60 

pp. 

Hill, J.L. and S.J. Fuchs. 2003. Special Ecological Area Pilot Study at the 

Garden Creek Ranch, Craig Mountain, Idaho - 2002 Field Season. 

Unpublished report on file at: The Nature Conservancy of Idaho Field 

Office, Sun Valley, Idaho. 16 pp. 

Hill, J.L. and K.L. Gray. 1999. Summary Report: Alien and rare plant inventory 

and vegetation mapping, Garden Creek Ranch, Craig Mountain, Idaho. 

Unpublished report on file at: The Nature Conservancy of Idaho Field 

Office, Sun Valley, Idaho. Cooperative Challenge Cost-share with Bureau 

of Land Management, Cottonwood Resource Area Headquarters, 

Cottonwood, Idaho. 131 pp. 

Hill, J.L. and K.L. Gray. 2000. Conservation of Spalding’s catchfly (Silene 

spaldingii) in the Lower Corral Creek Study Area, Garden Creek Ranch, 

Craig Mountain, Idaho - 1999 Field Season. Unpublished report on file at: 

The Nature Conservancy of Idaho Field Office, Sun Valley, Idaho. 18 pp. 

Hill, J.L. and K.L Gray. 2004a. Conservation Strategy for Spalding’s Catchfly 

(Silene spaldingii Wats.). Unpublished report prepared by the Idaho 

Conservation Data Center for the U.S. Fish and Wildlife Service, February 

2004. 153 pp. 

Hill, J.L. and K.L. Gray. 2004b. Population dynamics of Spalding’s silene 

(Silene spaldingii) in canyon grasslands at the Garden Creek Ranch, Craig 

Mountain, Idaho, 2003 field season. Palouse Clearwater Environmental 

Institute. 33 pp. 
Draft Recovery Plan for Silene spaldingii ! October 2005 

99 

Hill, J.L. and B.J. Weddell. 2003. Population dynamics of Spalding's Catchfly 

(Silene spaldingii Watts.) in the Lower Corral Creek Study Area, Garden 

Creek Ranch, Craig Mountain, Idaho - 2002 Field Season. Unpublished 

report, Challenge Cost-share for the Palouse-Clearwater Environmental 

Institute and the Bureau of Land Management, Cottonwood Resource 

Area, Cottonwood, Idaho. 29 pp. 

Hill, J.L., K.L. Gray, and S.J. Fuchs. 2001. Conservation of Spalding’s catchfly 

(Silene spaldingii) in the Lower Corral Creek Study Area, Garden Creek 

Ranch, Craig Mountain, Idaho - 2000 Field Season. Unpublished report 

on file at: The Nature Conservancy of Idaho Field Office, Sun Valley, 

Idaho. 15 pp. 

Hilty, J. H., D.J. Eldridge, R. Rosentreter, M.C. Wicklow-Howard, and M. 

Pellant. 2004. Recovery of biological soil crusts following wildfire in 

Idaho. Journal of Range Management 57:89-96. 

Hitchcock, C.L., and A. Cronquist. 1973. Flora of the Pacific Northwest. 

University of Washington Press, Seattle, Washington. 730 pp. 

Hitchcock, C.L. and B. Maguire. 1947. A revision of the North American 

species of Silene. University of Washington Publications in Biology, 

Volume 13, University of Washington Press, Seattle, Washington. 73 pp. 

Hitchcock, C.L., A. Cronquist, M. Ownbey, and J.W. Thompson. 1964. Vascular 

plants of the Pacific Northwest, Part 2: Salicaceae to Saxifragaceae. 

University of Washington Press, Seattle, Washington. 597 p. 

Hobbs, G.A. 1966. Ecology of species of Bombus Latr. (Hymenoptera: Apidae) 

in Southern Alberta. IV Subgenus Fervidobombus Skoridov. The 

Canadian Entomologist 98:33-39. 

Hobbs, R.J. and L.F. Huenneke. 1992. Disturbance, diversity and invasion: 

Implications for conservation. Conservation Biology 6:324-337. 

Huenneke, L.F. 1991. Ecological implications of genetic variation in plant 

populations. Pages 31 to 44 in D.A. Falk, and K.E. Holsinger (editors), 

Genetics and conservation of rare plants. Oxford University Press, New 

York, New York. 283 pp. 

Huenneke, L.F. and J.K. Thomson. 1995. Potential interference between a 

threatened endemic thistle and an invasive nonnative plant. Conservation 

Biology 9:416-425. 
Draft Recovery Plan for Silene spaldingii ! October 2005 

100 

Hull, A.C., Jr. and G.J. Klomp. 1966. Longevity of crested wheatgrass in the 

sagebrush-grass type in southern Idaho. Pages 5-11 in Utah Agricultural 

Experimentation Station Journal Paper 458. Logan, Utah and Twin Falls, 

Idaho. 

Hull, A.C., Jr. and G.J. Klomp. 1967. Thickening and spread of crested 

wheatgrass stands on southern Idaho ranges. Pages 222-227 in Utah 

Agricultural Experimentation Station Journal Paper 606. Logan, Utah and 

Twin Falls, Idaho. 

Karron, J.D., Y.B. Linhart, C.A. Chaulk, and C.A. Robertson. 1988. Genetic 

structure of populations of geographically restricted and widespread 

species of Astragalus (Fabaceae). American Journal of Botany 75:1114-

1119. 

Idaho Conservation Data Center. 2003. Element occurrence records for Silene 

spaldingii. Idaho Department of Fish and Game, Boise, Idaho. 46 pp. 

Idaho Department of Fish and Game. 2003. Project W-170-R-27 Progress 

Report, July 1, 2002 to June 30, 2003, Elk, Idaho. 109 pp. 

Jacquemyn, H., R. Brys, and M. Hermy. 2002. Patch occupancy, population size 

and reproductive success of a forest herb (Primula elatior) in a fragmented 

landscape. Oecologia 130:617-625. 

Jennersten, O. 1988. Pollination in Dianthus deltoides (Caryophyllaceae): Effect 

of habitat fragmentation on visitation and seed set. Conservation Biology 

2:359-366. 

Johansen, C.A., D.F. Mayer, J.D. Eves, and C.W. Kious. 1983. Pesticides and 

bees. Environmental Entomology 12:1513-1518. 

Johnson, C.G., Jr. and S.A. Simon. 1987. Plant associations of the WallowaSnake Province., Wallowa Whitman National Forest R6-ECOL-TP-355A86. U.S. Department of Agriculture, U. S. Forest Service, Pacific 

Northwest Region, Wallowa-Whitman National Forest, Baker City, 

Oregon. 399 pp. 

Jones, A. 2000. Effects of cattle grazing on North American arid ecosystems: a 

quantitative review. Western North American Naturalist 60:155-164. 

Kagan, J. 1989. Draft species management guide for Silene spaldingii. Oregon 

Natural Heritage Data Base, Portland, Oregon. 10 pp. 
Draft Recovery Plan for Silene spaldingii ! October 2005 

101 

Kephart, S.R. 2003. Plant-animal interactions in coastal and montane meadows: 

Rarity, re-introduction and pollination of Silene douglasii var. oraria. 

Page 42 In T.N. Kaye, M. Gisler, and R. Fiegener, editors. Proceedings of 

a conference on native plant restoration and management on public lands 

in the Pacific Northwest: Rare plants, invasive species and ecosystem 

management. February 11-13, 2003, Oregon State University, Corvallis, 

Oregon. Available online at <http://www.appliedeco.org/Restoration 

Conference2003/ConferenceProceedings03.htm>. Accessed 1 April 2005. 

Knick, Steven T., D.S. Dobkin, J.T. Rotenberry, M.A. Schroeder, W.M. Vander 

Haegen, and C. Van Riper III. 2003. Teetering on the edge of too late? 

Conservation and research issues for avifauna of sagebrush habitats. The 

Condor 105:611-634. 

Lande, R. 1995. Mutation and conservation. Conservation Biology 9:782-791. 

Lande, R., and G. F. Barrowclough. 1987. Effective population size, genetic 

variation, and their use in population management. Pages 87-123 in M.E. 

SoulJ, ed. Viable populations for conservation. Cambridge University 

Press, Cambridge, United Kingdom. 

Landres, P.B., P. Morgan, and F.J. Swanson. 1999. Overview of the use of 

natural viability concepts in managing ecological systems. Ecological 

Application 9:1179-1188. 

Lass, L.W., J.P. McCaffrey, D.C. Thill, and R.H. Callihan. 1999. Yellow 

starthistle biology and management in pasture and rangeland. Bulletin 

805. University of Idaho, College of Agriculture, Moscow, Idaho. 19 pp. 

Lennartsson, T. 2002. Extinction thresholds and disrupted plant pollinator 

interactions in fragmented plant populations. Ecology 83:3060-3072. 

Lesica, P. 1988a. Germination requirements and seedling biology of Spalding's 

Catchfly (Silene spaldingii). Unpublished paper prepared for The Nature 

Conservancy, Montana/Wyoming Office, Helena, Montana. 2 pp. 

Lesica, P. 1988b. A preliminary study of the pollination biology of Spalding's 

Catchfly in the Tobacco Valley, Lincoln County, Montana. Unpublished 

paper prepared for The Nature Conservancy, Montana/Wyoming Office, 

Helena, Montana. 5 pp. 

Lesica, P. 1988c. Monitoring Silene spaldingii on Wild Horse Island: 1988 

Progress Report. Unpublished paper prepared for The Nature 

Conservancy, Montana/Wyoming Office, Helena, Montana. 3 pp. 
Draft Recovery Plan for Silene spaldingii ! October 2005 

102 

Lesica, P. 1988d. Monitoring S. spaldingii on Dancing Prairie Preserve: 1988 

progress report. Unpublished report prepared for The Nature 

Conservancy, Montana Field Office, Helena, Montana. 15 pp. 

Lesica, P. 1991. Inbreeding depression and the importance of pollinators to the 

threatened plant, Silene spaldingii (Caryophyllaceae). Unpublished report 

prepared for The Nature Conservancy, Montana Field Office, Helena, 

Montana. 15 pp. 

Lesica, P. 1993. Loss of fitness resulting from pollinator exclusion in Silene 

spaldingii (Caryophyllaceae). Madroño 40:193-201. 

Lesica, P. 1994. The effects of fire on S. spaldingii at Dancing Prairie Preserve – 

1994 progress report. Unpublished report prepared for The Nature 

Conservancy, Montana Field Office, Helena, Montana. 17 pp. 

Lesica, P. 1995. Effects of fire on Silene spaldingii at Dancing Prairie Preserve: 

1995 progress report. Unpublished report to The Nature Conservancy 

Helena, Montana. 30 pp. 

Lesica, P. 1997. Demography of the endangered plant, Silene spaldingii

(Caryophyllaceae) in northwest Montana. Madroño 44:347-358. 

Lesica, P. 1999. Effects of fire on the demography of the endangered, geophytic 

herb Silene spaldingii (Caryophyllaceae). American Journal of Botany 

86:996-1002. 

Lesica, P. and B. Heidel. 1996. Pollination biology of Silene spaldingii. 

Unpublished report prepared for the Montana Field Office, The Nature 

Conservancy, Helena, Montana. 16 pp. 

Lesica, P. and B. Martin. 2003. Effects of prescribed fire and season of burn on 

recruitment of the invasive exotic plant, Potentilla recta, in a semiarid 

grassland. Restoration Ecology 11:516-523. 

Lesica, P. and J.S. Shelly. 1996. Competitive effects of Centaurea maculosa on 

the population dynamics of Arabis fecunda. Bulletin of the Torrey 

Botanical Club 123:111-121. 

Lesica, P. and B.M. Steele. 1994. Prolonged dormancy in vascular plants and 

implications for monitoring studies. Natural Areas Journal 14:209-212. 

Lesica, P. and B.M. Steele. 1996. A method for monitoring long-term population 

trends: an example using rare arctic-alpine plants. Ecological 

Applications 6: 879-887. 
Draft Recovery Plan for Silene spaldingii ! October 2005 

103 

Lesica, P. and B.M.Steele. 1997. Use of permanent plots in monitoring plant 

populations. Natural Areas Journal 17: 331-340. 

Lichthardt, J. 1997. Revised report on the conservation status of Silene 

spaldingii in Idaho. Conservation Data Center, Idaho Department of Fish 

and Game, Boise, Idaho. 20 pp. 

Lichthardt, J. and K. Gray. 2002. Field surveys for Silene spaldingii (Spalding’s 

catchfly) in Idaho, 2001. Idaho Department of Fish and Game, 

Conservation Data Center, Boise, Idaho. 14 pp. 

Lichthardt, J., and R.K. Moseley. 1997. Status and conservation of the Palouse 

grassland in Idaho. Conservation Data Center, Idaho Department of Fish 

and Game, Boise, Idaho. 28 pp. 

Lienert, J. and M. Fischer. 2003. Habitat fragmentation affects the common 

wetland specialist Primula farinosa in north-east Switzerland. Journal of 

Ecology 91:587-599. 

Loveless, M.D., and J.L. Hamrick. 1984. Ecological determinants of genetic 

structure in plant populations. Annual Review of Ecology and 

Systematics. 15:65-95. 

Lynch, M., J. Conery, and R. Burger. 1995. Mutation accumulation and the 

extinction of small populations. American Naturalist 146:489-518. 

Mack, R.N. 1981. Invasion of Bromus tectorum L. into Western North America: 

An ecological chronicle. Department of Botany, Washington State 

University, Pullman, Washington. Agro-Ecosystems 7:145-165. 

Mack, R. N. and J.N. Thompson. 1982. Evolution in steppe with few large, 

hooved mammals. American Naturalist 119:757-773. 

Menges, E.S. 1990. Population viability analysis for an endangered plant. 

Conservation Biology 4:52-62. 

Menges, E. S. 1991a. Seed germination percentage increases with population 

size in a fragmented prairie species. Conservation Biology 5:158-164. 

Menges, E. 1991b. The application of minimum viable population theory to 

plants.. Pages 45-61 in D.A. Falk, and K.E. Holsinger (editors), Genetics 

and conservation of rare plants. Oxford University Press, New York, New 

York. 283 pp. 

Menges, E. 1995. Factors limiting fecundity and germination in small 

populations of Silene regia (Caryophyllaceae), a rare hummingbirdpollinated prairie forb. American Midland Naturalist 133:242-255. 
Draft Recovery Plan for Silene spaldingii ! October 2005 

104 

Menges, E.S. 2000. Population viability analyses in plants: challenges and 

opportunities. Trends in Ecology and Evolution 15:51-56. 

Menges, E.S. and R.W. Dolan. 1998. Demographic viability of populations of 

Silene regia in Midwest Prairies: Relationships with fire management, 

genetic variation, geographic location, population size and isolation. 

Journal of Ecology 86:63-78. 

Menke, C. 2003. Relationships of exotic species and wildfire to the threatened 

plant Silene spaldingii. M.S. Thesis. Department of Botany and Plant 

Pathology, Oregon State University, Corvallis, Oregon. 73 pp. 

Menke, C. A. and P.S. Muir. 2004. Patterns and influences of exotic species 

invasion into the grassland habitat of the threatened plant Silene 

spaldingii. Natural Areas Journal 24: 119-128. 

Miller, P and P. Westra. 2004. Herbicide surfactants and adjuvants. Colorado 

State University Cooperative Extension. No. 0.559. Available online at 

<http://www.ext.colostate.edu/pubs/crops/00559.html>. Accessed 2 July 

2004. 

Montana Natural Heritage Program. 2003. Element occurrence records for Silene 

spaldingii. Helena, Montana. 

Mooney, H.A. and E.E. Cleland. 2001. The evolutionary impact of invasive 

species. Proceedings of the National Academy of Sciences of the United 

States of America. 98:5446-5451. 

Mueggler, W.F. and W.L. Stewart. 1980. Grassland and shrubland habitat types 

of western Montana. Intermountain Forest and Range Experiment Station. 

U.S. Department of Agriculture. Forest Service General Technical Report 

INT-66. Ogden, Utah. 153 pp. 

Mueller, M. and T. Mueller. 1997. Pages 24-29 and 74-77 in Fire, faults and 

floods. University of Idaho Press, Moscow, Idaho. 

Mutch, R. W., S.F. Arno, J.K. Brown, C.E. Carlson, R.D. Ottmar, and J.L. 

Peterson. 1993. Forest health in the Blue Mountains: A management 

strategy for fire-adapted ecosystems. U.S. Dept of Agriculture Forest 

Service, Pacific Northwest Research Station, February 1993. 15 pp. 

Narolski, S. W. 1996. Pages 1-9 and 39-45 in Forest inventory. Peter J. Johnson 

Wildlife Mitigation Unit. Prepared for: U.S. Department of Energy, 

Bonneville Power Administration, Project No. 92-069. 

Neel, M.C., and M.P. Cummings. 2003. Effectiveness of conservation targets in 

capturing genetic diversity. Conservation Biology 17:219-229. 
Draft Recovery Plan for Silene spaldingii ! October 2005 

105 

Newman, D., and D. Pilson. 1997. Increased probability of extinction due to 

decreased genetic effective population size: experimental populations of 

Clarkia pulchella. Evolution 51:354-362. 

Newman, D. and D.A. Tallmon. 2001. Experimental evidence for beneficial 

fitness effects of gene flow in recently isolated populations. Conservation 

Biology 15:1054-1063. 

Noss, R.F. 1995. What should endangered ecosystems mean to the Wildlands 

Project? Wild Earth 5: 20-29.

Noss, R.F. and A.Y Cooperrider. 1994. Saving nature’s legacy: protecting and 

restoring biodiversity. Defenders of Wildlife and Island Press, 

Washington D.C. 416 pp. 

Noss, R.F., E.T. LaRoe III, and J.M. Scott. 1995. Endangered ecosystems of the 

United States: a preliminary assessment of loss and degradation. 

Biological Report 28. U.S. Department of the Interior, National 

Biological Service, Washington, D.C. 58 pp. 

Nunney, L., and K.A. Campbell. 1993. Assessing minimum viable population 

size: demography meets population genetics. Trends in Ecology and 

Evolution 8:234-239. 

Oliphant, J.O. 1934. The botanical labors of the reverend Henry H. Spalding. 

Washington Historical Quarterly 25:93-102. 

Olson, B.E. 1999. Impacts of noxious weeds on ecologic and economic systems. 

Pages 6-18 in: R. L. Sheley, J.K. Petroff (editors), Biology and 

management of noxious rangeland weeds. Oregon State University Press, 

Corvallis, Oregon. 

Olson, B.E., R.T. Wallander, and J.R. Lacey. 1997. Effects of sheep grazing on a 

spotted knapweed infested Idaho fescue community. Journal of Range 

Management 50:386-390. 

Oostermeijer, J.G.B., S.H. Luijten, and J.C.M. Den Nijs. 2003. Integrating 

demographic and genetic approaches in plant conservation. Biological 

Conservation 113:389-398. 

Oregon Department of Agriculture. 2004. Oregon administrative rule. Division 

73. Plants: wildflowers, and endangered, threatened, and candidate 

species. Oregon State Archives. Available online at 

<http://arcweb.sos.state.or.us/rules/OARS_600/OAR_603/603_073.html>.

Accessed 14 April 2004. 
Draft Recovery Plan for Silene spaldingii ! October 2005 

106 

Oregon Natural Heritage Program. 2003. Element occurrence records for Silene 

spaldingii. Portland, Oregon. 

Osborne, J.L., S.J. Clark, R.J. Morris, I.H. Williams, J.R. Riley, A.D. Smith, D.R. 

Reynolds, and A.S. Edwards. 1999. A landscape-scale study of bumble 

bee foraging range and constancy using harmonic radar. Journal of 

Applied Ecology 36:519-533. 

Pavlik, B.M. 1994. Demographic monitoring and the recovery of endangered 

plants. Pages 322-350 in M.L. Bowles, and C. Whelan (editors), 

Recovery and Restoration of Endangered Species. Cambridge University 

Press, Cambridge, United Kingdom. 

Pavlik, B.M., D.L. Nickrent, and A.M. Howald. 1993. The recovery of an 

endangered plant. I. Creating a new population of Amsinckia grandiflora. 

Conservation Biology 7:510-526. 

Randall, J. 1996. Weed control for the preservation of biological diversity. 

Weed Technology 10:370-383.

Richards, A.J. 1997. Pages192-193 in Population biology and gene flow, plant 

breeding systems. Second Edition. Chapman and Hall, United Kingdom. 

Roché, B.F., Jr. 1965. Ecologic studies of yellow starthistle (Centaurea 

solstitialis L.). Ph.D. Dissertation. University of Idaho, Moscow, Idaho. 

78 pp. 

Rush, T. and J. Gamon. 1999. Management plan for Spalding's catchfly (Silene 

spaldingii) on Fairchild Air Force Base, Washington. Unpublished report 

by the Washington Natural Heritage Program, Olympia, Washington. 15 

pp. 

Saunders, D.A., R.J. Hobbs, and C.R. Margules. 1991. Biological consequences 

of ecosystem fragmentation: A review. Conservation Biology 5:18-32. 

Schassberger, L. A. 1988. Report on the conservation status of Silene spaldingii, 

a candidate threatened species. Montana Natural Heritage Program, 

Helena, Montana. 67 pp. 

Schemske, D.W., B.C. Husband, M.H. Ruckelshaus, C. Goodwillie, I.M. Parker, 

and J.G. Bishop. 1994. Evaluating approaches to the conservation of rare 

and endangered plants. Ecology 75:584-606. 

Schonewald-Cox, C.M., S.M, Chambers, B. MacBryde, and L. Thomas. 1983. 

Genetics and conservation. A reference for managing wild animal and 

plant populations. 469 pp. 
Draft Recovery Plan for Silene spaldingii ! October 2005 

107 

Schultz, B.W. and W.K. Ostler. 1995. Effects of prolonged drought on 

vegetation associations in the northern Mojave Desert. Pages 228-235 in

B.A. Roundy, E.D. McArthur, J.S. Haley, and D.K. Mann (editors), 

Proceedings: Wildland shrub and arid land restoration symposium. United 

States Department of Agriculture Forest Service. General Technical 

Report INT-GTR-315. 

Shaffer, M. 1987. Minimum viable populations: coping with uncertainty. Pages 

69-86 in M.E. SoulJ (editor). Viable populations for conservation. 

Cambridge University Press, Cambridge, United Kingdom. 

Shefferson, R.P., B.K. Sandercock, J. Proper, and S.R. Beissinger. 2001. 

Estimating dormancy and survival of a rare herbaceous perennial using 

mark-recapture models. Ecology 82: 145-156. 

Silvertown, J., M. Franco, I. Pisanty, and A. Mendoza. 1993. Comparative plant 

demography, relative importance of life-cycle components to the finite 

rate of increase in woody and herbaceous perennials. Journal of Ecology 

81:465-476. 

Simberloff, D. 1988. The contribution of population and community biology to 

conservation science. Annual Review of Ecology and Systematics 

19:473-511. 

SoulJ, M.E. (editor). 1987. Viable populations for conservation. Cambridge 

University Press, Cambridge, United Kingdom. 

SoulJ, M.E., and D. Simberloff. 1986. What do genetics and ecology tell us 

about the design of nature reserves? Biological Conservation 35:19-40. 

Steffan-Dewenter, I. and T. Tscharntke. 1999. Effects of habitat isolation on 

pollinator communities and seed set. Oecologia 121:432-440. 

Stephen, W.P., G.E. Bohart, and P.F. Torchio. 1969. The biology and external 

morphology of bees. Agricultural Experiment Station, Oregon State 

University, Corvallis, Oregon. 140 pp. 

Sugden, E.A. 1985. Pollinators of Astragalus monoensis Barneby (Fabaceae): 

new host records; potential impact of sheep grazing. Great Basin 

Naturalist 45:299-312. 
Draft Recovery Plan for Silene spaldingii ! October 2005 

108 

Tepedino, D.W. 1996. The reproductive biology of rare rangeland plants and 

their vulnerability to insecticides. In Environmental Monitoring and 

Evaluation G.L. Cunningham and M.W. Sampson (editors), Grasshoppers: 

Their biology, identification and management, user handbook. Section III. 

Available online at 

<http://www.sidney.ars.usda.gov/grasshopper/Handbook/III/index.htm>. 

Accessed 26 November 2003. 

Thorp, R.W., D.S. Horning, Jr., and L.L. Dunning. 1983. Bumble bees and 

cuckoo bumble bees of California (Hymenoptera: Apidae). University of 

California Publications, Bulletin of the California Insect Survey. 7 pp. 

Tisdale, E.W. 1983. Grasslands of western North America: The Pacific 

Northwest Bunchgrass. Pages 223-245 in A.C. Nicholson, A. McLean, 

and T.E. Baker (editors), Grassland ecology and classification symposium 

proceedings, Ministry of Forest, Province of British Columbia, Victoria, 

British Columbia, Canada. 

Tisdale, E.W. 1986a. Canyon grasslands and associated shrublands of westcentral Idaho and adjacent areas. Bulletin No. 40. Forest, Wildlife and 

Range Experiment Station, University of Idaho, Moscow, Idaho. 42 pp. 

Tisdale, E.W. 1986b. Native vegetation of Idaho. Rangelands 8:202-207. 

U.S. Bonneville Power Administration. 2003. Peter T. Johnson Unit becomes a 

model of restoration. June 2003 DOE/BP-3526. 4 pp. 

U.S. Bureau of Land Management. 1998. Summary for 1998 special status plant 

monitoring survey, and management and 1999 planned work. BLM 

Cottonwood Resource Area. 3 pp. 

U.S. Bureau of Land Management. 2001. Cottonwood Field Office, Craig 

Mountain Cooperative Management Area Environmental Assessment Fire 

Management Plan. January 31, 2001. Upper Columbia Salmon – 

Clearwater District. Cottonwood, Idaho. 

U.S. Bureau of Land Management. 2002. Programmatic Biological Assessment 

with monitoring protocols (with programmatic BA) Spokane District, 

Border Resource Area. Spokane Washington. 14 pp. 

U. S. Department of Energy. 2004. Model predicts wet winters; dry summers for 

northwest, state energy office project brief. U.S. Department of energy – 

Energy efficiency and renewable energy state energy program. Available 

on line at <http://eere.energy.gov/state energy program/project brief 

detail.cfm/pb id=96?print>. Accessed 7 July 2004. 
Draft Recovery Plan for Silene spaldingii ! October 2005 

109 

U.S. Environmental Protection Agency. 2004. Ecoregions of Oregon, Montana, 

Idaho. Western Ecology Division, Corvallis, Oregon. Available online at 

<http://www.epa/gov/wed.pages/ecoretions/level iv.htm>. Accessed 6 

July 2004. 18 pp. 

U.S. Fish and Wildlife Service. 2002. Biological Opinion transmitted in a 

Memorandum dated 1/10/02 from State Supervisor/Deputy State 

Supervisor, Oregon Fish and Wildlife Office, Portland, Oregon to District 

Manager, Vale District Bureau of Land Management, Vale, Oregon. 

Subject: Formal Section 7 Consultation for the Bureau of Land 

Management’s Vale District Integrated Noxious Weed Management 

Program, 2001 to 2011 (ref. no.1-7-F-01-319). 

Velterop, O. 2000. Effects of fragmentation on pollen and gene flow in insectpollinated plant populations. Master’s thesis, University of Groningen, 

The Netherlands. 156 pp. 

Washington Natural Heritage Program. 2003. Element occurrence records for 

Silene spaldingii, Olympia, Washington. 

Watson, S. 1875. Revision of the genus Ceanothus, and descriptions of new 

plants, with a synopsis of the western species of Silene. Proceedings of 

the American Academy of Science 10:333-350. 

Weddell, B.J. 2002. Field surveys for Silene spaldingii at Turnbull National 

Wildlife Refuge, Swanson Lakes Wildlife Area, and Wawawai Canyon 

DNR Parcel, August-September 2002. Report for the Department of 

Natural Resources, State of Washington. 7 pp. 

Weddell, B.J. 2001. Fire in Steppe Vegetation of the Northern Intermountain 

Region. Idaho Bureau of Land Management, Technical Bulletin No. 01-

14, August 2001. 

Wentworth, J. 1996. Conservation recommendations for Silene spaldingii in 

Washington. Washington Natural Heritage Program, Olympia, 

Washington. 12 pp. 

Westbrooks, R. 1998. Federal Interagency Committee for the Management of 

Noxious and Exotic Weeds, Department of Defense. Invasive Plant Fact 

Book. Available online at <http://ww.denix.osd.mil/denix/Public/ESPrograms/Conservation/Invasive/contents.htm>. Accessed 26 March 

2004. 

Westerbergh, A. and A. Saura. 1994. Genetic Differentiation in endemic Silene 

(Caryophyllaceae) on the Hawaiian Islands. American Journal of Botany. 

81:1487-1493. 
Draft Recovery Plan for Silene spaldingii ! October 2005 

110 

Western Regional Climate Center. 2003a. Climates of Idaho, Montana, Oregon 

and Washington. Available online at 

<http://www.wrcc.dri.edu/narratives>. Accessed 8 July 2004. 

Western Regional Climate Center. 2003b. Period of record general climate 

summaries. Available online at <http://www.wrcc.dri.edu/cgibin/cliGCStP.pl?>. Accessed 6 August 2003. 

Whisenant, S.G. 1990. Changing fire frequencies on Idaho's Snake River Plains: 

ecological and management implications. Pages 4-10 in E.D. McArthur, 

E.M. Romney, S.D. Smith, and P.T. Tueller (editors), Proceedings of a 

Symposium on Cheatgrass Invasion, Shrub Die-off, and Other Aspects of 

Shrub Biology and Management. U.S. Forest Service General Technical 

Report INT-276, Intermountain Forest and Range Experiment Station, 

Ogden, Utah. 

Whitson, T.D., Burrill, L.C., S.A. Dewey, D.W. Cudney, B.E. Nelson, R.D. Lee, 

and R. Parker. 1996. Pages 88-89 in Weeds of the West, fifth edition. 

Western Society of Weed Science, Newark, California. 630 pp. 

Wilson, E.O. 1989. Threats to biodiversity. Scientific American September:108-

116. 

Young, J.A. 1994. History and use of semiarid plant communities - changes in 

vegetation. Pages 5-7 in S.B. Monsen and S.G. Kitchen (editors), 

Proceedings: ecology and management of annual Rangelands; U.S. 

Department of Agriculture, Forest Service, Intermountain Research 

Station, General Technical Report INT-GTR-313. 

Youtie, B. 1990. Silene spaldingii study on Clear Lake Ridge Preserve. 

Unpublished report for The Nature Conservancy of Oregon. 7 pp. 
Draft Recovery Plan for Silene spaldingii ! October 2005 

111 

IN LITT. REFERENCES 

Benner, Barbara. 1993. Botanist, U.S. Bureau of Land Management, Spokane, 

Washington. Edna Rey-Vizgirdas, Botanist, U.S. Fish and Wildlife 

Service, Boise, Idaho. Occurrence of Silene spaldingii in Lincoln Co. 

Washington. 5 pp. 

Benner, Barbara, 1995. Botanist, U.S. Bureau of Land Management, Spokane, 

Washington. To Edna Rey-Vizgirdas, Botanist, U.S. Fish and Wildlife 

Service, Boise, Idaho. Silene spaldingii information in Washington. 1 

April 1995. 1 p. 

Benner, Barbara. 1999. Botanist, U.S. Bureau of Land Management, Spokane, 

Washington. To Edna Rey-Vizgirdas, Botanist, U.S. Fish and Wildlife 

Service, Boise, Idaho. Information on Silene spaldingii in the Border 

Resource Area. 7 January 1999. 3 pp. 

Benner, Barbara. 2003. Botanist, U.S. Bureau of Land Management, Spokane, 

Washington. T Janice Hill, private consultant, Deary, Idaho. Letter and 

questionnaire regarding Silene spaldingii. 6 May 2003. 7 pp. 

Benner, Barbara. 2004. Botanist, U.S. Bureau of Land Management, Spokane, 

Washington. To Marilyn Hemker, Fish and Wildlife Biologist, U.S. Fish 

and Wildlife Service, Boise, Idaho. Programmatic Biological Assessment. 

5 August 2002. 78 pp. 

Brusven, Annette. 2004. Horticulturalist, University of Idaho Forest Nursery, 

Moscow, Idaho. To Gina Glenne, Botanist, U.S. Fish and Wildlife 

Service, Boise, Idaho. Information on seedlings grown at the nursery. 25 

June 2004. 4 pp. 

Button, Clair. 2005. Botanist, U. S. Bureau of Land Management, Baker City, 

Oregon. To Gina Glenne, Botanist, U.S. Fish and Wildlife Service, Boise, 

Idaho. Survey efforts for Silene spaldingii. 19 January 2005. 1 pp. 

Caplow, Florence. 2003. Botanist, Washington Natural Heritage Program, 

Olympia, Washington. To Janice Hill, private consultant, Deary, Idaho. 

Letter and questionnaire regarding Silene spaldingii. 21 May 2003. 5 pp. 

Danly, L. A. 2004. Rangeland Management Specialist, U.S. Bureau of Land 

Management, Cottonwood, Idaho. Tri-State Weed Management Area, 

2003 End–of-Year-Report. 9 pp. 
Draft Recovery Plan for Silene spaldingii ! October 2005 

112 

DiTomaso, Joseph M. 2000. Invasive weeds in rangelands: Species, impacts, 

and management. Available online at Bioone.org/bione/?request=getdocument&issn-0043-1745&volume+048&is. Accessed 27 May 2004. 

15 pp. 

Glenne, Gina. 2003. Botanist, U.S. Fish and Wildlife Service, Boise, Idaho. To 

Janice Hill, private consultant, Deary, Idaho. Comments on draft 

conservation strategy, grazing of S. spaldingii plants at Zumwalt Prairie. 

23 September 2003. 1 p. 

Glenne, Gina. 2004a. Botanist, U.S. Fish and Wildlife Service, Boise, Idaho. 

Table that lists the number of extant, extirpated, historical or unknown 

populations determined by Edna Rey-Vizgirdas, Janice Hill and Gina 

Glenne as of 2000. 24 June 2004. 6 pp. 

Glenne, Gina. 2004b. Botanist, U.S. Fish & Wildlife Service, Boise, Idaho. To 

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. 

To Gina Glenne, Botanist, U.S. Fish and Wildlife Service, Boise, Idaho. 

Comments on the Silene spaldingii draft recovery strategy. 1 June 2004. 

3 pp.

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. 2003. Private Consultant, Deary, Idaho. To Janice Hill private 

consultant, Deary, Idaho. Questionnaire regarding Silene spaldingii 

population status including extensive documentation compiled by Janice 

Hill. 14 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. 1 p. 

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. 1 p. 

Johnson, Craig. 1997. Fisheries Biologist, U.S. Bureau of Land Management, 

Cottonwood, Idaho. Unauthorized Herbicide Spraying of Blackhawk 

Colony of MacFarlane’s Four-O’clock (Mirabilis macfarlanei). 27 June 

1997. 6 pp. 
Draft Recovery Plan for Silene spaldingii ! October 2005 

113 

Lesica, Peter. 2003. Private consultant, Missoula, Montana. To Gina Glenne, 

Botanist, U.S. Fish and Wildlife Service, Boise, Idaho. Comments on 

beginning and end portions of the draft conservation strategy for S. 

spaldingii. 6 November 2003. 3 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. 

Mantas, Maria. 2003. Botanist, The Nature Conservancy, Helena, Montana. To 

Janice Hill, private consultant, Deary, Idaho. Comments on the Draft 

conservation strategy for Silene spaldingii in Montana. 17 November 

2003. 6 pp. 

Martin, Brian. 1998. Director of Science and Stewardship, The Nature 

Conservancy, Helena, Montana. To Janice Hill private consultant, Deary, 

Idaho . Silene Spaldingii conservation strategy questionnaire. 24 March 

2003. 5 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. 

Rey-Vizgirdas, Edna. 1999. Botanist, U.S. Fish & Wildlife Service, Boise, 

Idaho. U. S. Fish and Wildlife Status Review for Silene spaldingii. 11 

January 1999. 10 pp. 

Sondenaa, Angela. 2003. Botanist, Nez Perce Tribe, Lapwai, Idaho. To Janice 

Hill, private consultant, Deary, Idaho. Grant proposal for Silene spaldingii

surveys on Nez Perce Tribal lands in Idaho, Washington and Oregon. 28 

May 2003. 1 p. 

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. 7 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. Environmental Protection Agency. 2000. Global warming-climate. 

Available online at 

<http://yosemite.epa.gov/oar/globalwarming.nsf/content/climate.html>. 

Accessed 6 July 2004. 
Draft Recovery Plan for Silene spaldingii ! October 2005 

114 

U.S. Fish and Wildlife Service. 2004. Notes from public meetings held in 

Montana , Idaho, Washington and Oregon February and March 2004. 9 

pp. 

U.S. Fish and Wildlife Service. 2003. Supervisor, U.S. Fish and Wildlife 

Service, Boise, Idaho. To Field Manager, U.S. Bureau of Land 

Management, Cottonwood, Idaho. Bureau of Land Management Noxious 

Weed Control Program in the Snake, Salmon and Clearwater River 

Drainages, Idaho County, Idaho – Biological assessment and concurrence 

File #1005.2000 1-4-03-I-420. 3 April 2003. 15 pp. 

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. 

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 Area properties. 16 December 2003. 1 p. 

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. 
Draft Recovery Plan for Silene spaldingii ! October 2005 

115 

PERSONAL COMMUNICATIONS 

Bjork, Curtis. 2003. Private consultant, Canada. Notes from Silene spaldingii

Conservation Strategy meeting in Lewiston, Idaho. Potential unsurveyed 

habitat for S. spaldingii exists at Bob Marshall Wilderness area, Flathead 

Indian Reservation, Lost Trail NWR, and the National Bison Range. 28 

October 2003. 1 p. 

Glenne, Gina. 2003. Botanist, U.S. Fish & Wildlife Service, Boise, Idaho. To 

Jim White, Manager, Idaho Department of Fish and Game. Silene 

spaldingii on Craig Mountain Wildlife Management Area properties. 16 

December 2003. 1 p. 

 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.
Draft Recovery Plan for Silene spaldingii ! October 2005 

116 

Appendix A. Endangered and Threatened Species Recovery 

Priority Number Guidelines* 

Degree of 

Threat

Recovery 

Potential Taxonomy Conflict?† Priority

Monotypic Yes 1C 

Genus No 1 

Species Yes 2C 

No 2 

Yes 3C 

High 

Subspecies 

No 3 

Monotypic Yes 4C 

Genus No 4 

Species Yes 5C 

No 5 

Yes 6C 

 

High 

 

Low 

Subspecies 

No 6 

Monotypic Yes 7C 

Genus No 7 

Species Yes 8C 

No 8 

Yes 9C 

High 

Subspecies 

No 9 

Monotypic Yes 10C 

Genus No 10 

Species Yes 11C 

No 11 

Yes 12C 

Moderate 

Low 

Subspecies 

No 12 

Monotypic Yes 13C 

Genus No 13 

Species Yes 14C 

No 14 

Yes 15C 

High 

Subspecies 

No 15 

Monotypic Yes 16C 

Genus 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.
Draft Recovery Plan for Silene spaldingii ! October 2005 

117 

Appendix B. Scientific and common names used in text 

 

Plants

Scientific name Common name 

Acroptilon repens Russian knapweed 

Agropygron desortum crested wheatgrass 

Agropygron spicatum = Pseudoroegneria 

spicata bluebunch wheatgrass 

Amsinckia grandiflora large-flowered fiddleneck 

Arabis fecunda Mt. Sapphire rockcress 

Artemesia tridentata big sagebrush 

Artemesia tripartita three-tip sagebrush 

Aster jessicae Jessica’s aster 

Astragalus riparius Piper’s milk-vetch 

Bromus inermis smooth brome 

Bromus japonicus Japanese brome 

Bromus tectorum cheatgrass 

Calochortus macroscarpus var. maculosus green-band mariposa lily 

Calochortus nitidus broad-fruit mariposa 

Cardaria draba whitetop 

Centaurea diffusa diffuse knapweed 

Centaurea maculosa spotted knapweed 

Centaurea solstitialis yellow starthistle 

Chondrilla juncea rush skeletonweed 

Cirsium arvense Canada thistle 

Cirsium brevifolium Palouse thistle 

Cirsium vinaceum Sacramento Mountains thistle 
Draft Recovery Plan for Silene spaldingii ! October 2005 

118 

Appendix B. Scientific and Common Names used in Text (continued) 

Plants

Scientific name Common name

Crupina vulgaris common crupina 

Dianthus deltoids maiden pink 

Dipsacus sylvestris = Dipsacus fullonum 

spp. sylvestris teasel 

Euphorbia esula leafy spurge 

Festuca idahoensis Idaho fescue 

Festuca scabrella rough fescue 

Happlopappus liatriformis Palouse goldenweed 

Hesperostipa comata = Stipa comata needle-and-thread grass 

Hieracium pretense meadow hawkweed 

Hypericum perforatum St. Johnswort 

Koeleria cristata prairie junegrass 

Lepidium latifolium perennial pepperweed 

Linaria dalmatica Dalmatian toadflax 

Linaria spp. toadflax 

Lupinus sericeus silky lupine 

Mirabilis macfarlanei Macfarlane’s four-o’clock 

Onopordum acanthium Scotch thistle 

Pinus ponderosa ponderosa pine 

Poa pratensis Kentucky bluegrass 

Polemonium pectinatum Washington polemonium 

Potentilla recta sulfur cinquefoil 

Primulus elatior oxlip 

Rosa spp. rose 

Rubus nigerrimus Northwest raspberry 
Draft Recovery Plan for Silene spaldingii ! October 2005 

119 

Appendix B. Scientific and Common Names used in Text (continued) 

Plants

Scientific name Common name

Scabiosa columbaria dove pincushions, pincushion flower 

Silene cserei Balkan catchfly 

Silene douglasii Douglas’ catchfly 

Silene hawaiiensis Hawai`i catchfly 

Silene latifolia ssp. alba bladder campion 

Silene oregana Oregon catchfly 

Silene regia royal catchfly 

Silene scaposa var. scaposa Scapose silene 

Silene scouleri Scouler’s catchfly 

Silene spaldingii Spalding’s catchfly, Spalding’s silene, 

Spalding’s campion 

Symphoricarpos albus snowberry 

Trifolium plumosum var. amplifolium plumed clover 

Ventenata dubia ventenata 

 

 

Animals

Scientific Name Common Name or Type of Animal 

Bombus fervidus bumblebee 

Bombus terrestris bumblebee 

Lasioglossum spp. solitary bee 

Halictus tripartitus solitary bee 

Dienoplus rugulosis solitary bee 

Apis spp. honey bee 

Tympanuchus phasianellus columbianus Columbian sharp-tailed grouse 
120

Appendix C. Summary of Threats and Recommended Recovery Actions for Silene 

This table identifies the recovery actions recommended to address the threats to Silene spaldingii, as well as thos

that will provide a measure of the elimination or sufficient reduction of those threats to consider delisting of this 

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. 

Basins; 1.2.3. control in Canyon Grasslands; 1.3.2. control in the Channecontrol in the Intermontane Valleys; 1.5.4. control in the Palouse Grasslamanagement plans; 2.3 habitat management plans; 2.3.1 invasive nonnatimonitor; 2.5.3 control research; 2.7 private land conservation; 2.10 fundin

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 gen

2.3 habitat management plans; 2.4 monitor; 2.5.1 population viabilities; populations; 2.5.6 reproductive biology research; 2.5.7 seed dispersal resresearch; 2.7 private land conservation; 2.9 propagule banks, 2.10 fundin

A Changes in the Fire Regime and 

Fire Effects 

2, 3, 4, 6 1. conserve and expand populations in each physiographic region; 2.1 gen

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 gen

2.3 habitat management plans; 2.3.3 protect from development; 2.4 moniprivate land conservation; 2.10 funding 

A, C Livestock Grazing and 

Trampling 

2, 3, 4 1. conserve and expand populations in each physiographic region; 2.1 gen

2.3 habitat management plans; 2.3.4 manage livestock grazing; 2.4 monitprivate land conservation; 2.10 funding 

E Herbicide and Insecticide 

Spraying 

2, 3, 4 1. conserve and expand populations in each physiographic region; 2.1 gen

2.3 habitat management plans; 2.3.1.6 herbicide application guidelines; 2research; 2.7 private land conservation; 2.10 funding 
121

Appendix C. Summary of Threats and Recommended Recovery Actions for Silene spald

C Grazing (Herbivory) and 

Trampling by Wildlife Species 

2, 3, 4 1. conserve and expand populations in each physiographic region; 2.1 gen

2.3 habitat management plans; 2.3.6 monitor and manage wildlife; 2.4 moprivate land conservation; 2.10 funding 

A, E Off-Road Vehicle Use 2, 3, 4 1. conserve and expand populations in each physiographic region; 2.1 gen

2.3 habitat management plans; 2.3.5 implement off-road vehicle control; land conservation; 2.10 funding 

C Insect Damage and Disease 2, 3, 4 1. conserve and expand populations in each physiographic region; 2.1 gen

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 gen

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 gen

2.3 habitat management plans; 2.4 monitor; 2.7 private land conservationspecies 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 
Region 1

U.S. Fish and Wildlife Service

Ecological Services

911 NE. 11th Avenue

Portland, Oregon 97232-4181

October 2005