Warning This Web page has been archived on the Web.

Archived Content

Information identified as archived on the Web is for reference, research or recordkeeping purposes. It has not been altered or updated after the date of archiving. Web pages that are archived on the Web are not subject to the Government of Canada Web Standards, as per the Policy on Communications and Federal Identity.

Skip booklet index and go to page content

Part 2: Multi-species Recovery Strategy for the Princeton Landscape, Including Dwarf Woolly-heads (Psilocarphus brevissimus var. brevissimus), Slender Collomia (Collomia tenella), and Stoloniferous Pussytoes (Antennaria flagellaris) in British Columbia, prepared by the Southern Interior Rare Plants Implementation Group, for the British Columbia Ministry of Environment

Multi-species Recovery Strategy for the Princeton Landscape, Including Dwarf Woolly-heads (Psilocarphus brevissimus var. brevissimus), Slender Collomia (Collomia tenella), and Stoloniferous Pussytoes (Antennaria flagellaris) in British Columbia

 

Photo: Princeton Landscape plants (Dwarf Woolly-heads – Southern Mountain population, Slender Collomia and Stoloniferous Pussytoes)

Prepared by the Southern Interior Rare Plants Recovery Implementation Group

 

British Columbia -- Ministry of Environment

Table of Contents – Part 2

Document Information – Part 2

List of Tables

List of Figures

Top of Page


Document Information – Part 2

About the British Columbia Recovery Strategy Series

This series presents the recovery strategies that are prepared as advice to the Province of British Columbia on the general strategic approach required to recover species at risk. The Province prepares recovery strategies to meet its commitments to recover species at risk under the Accord for the Protection of Species at Risk in Canada, and the Canada – British Columbia Agreement on Species at Risk.

What is recovery?

Species at risk recovery is the process by which the decline of an endangered, threatened, or extirpated species is arrested or reversed, and threats are removed or reduced to improve the likelihood of a species’ persistence in the wild.

What is a recovery strategy?

A recovery strategy represents the best available scientific knowledge on what is required to achieve recovery of a species or ecosystem. A recovery strategy outlines what is and what is not known about a species or ecosystem; it also identifies threats to the species or ecosystem, and what should be done to mitigate those threats. Recovery strategies set recovery goals and objectives, and recommend approaches to recover the species or ecosystem.

Recovery strategies are usually prepared by a recovery team with members from agencies responsible for the management of the species or ecosystem, experts from other agencies, universities, conservation groups, aboriginal groups, and stakeholder groups as appropriate.

What’s next?

In most cases, one or more action plan(s) will be developed to define and guide implementation of the recovery strategy. Action plans include more detailed information about what needs to be done to meet the objectives of the recovery strategy. However, the recovery strategy provides valuable information on threats to the species and their recovery needs that may be used by individuals, communities, land users, and conservationists interested in species at risk recovery.

For more information

To learn more about species at risk recovery in British Columbia, please visit the Ministry of Environment Recovery Planning.

Multi-species Recovery Strategy for the Princeton Landscape, Including Dwarf Woolly-heads (Psilocarphus brevissimus var. brevissimus), Slender Collomia (Collomia tenella), and Stoloniferous Pussytoes (Antennaria flagellaris) in British Columbia

Prepared by the Southern Interior Rare Plants Recovery Implementation Group

June 2008

Recommended citation

Southern Interior Rare Plants Recovery Implementation Group. 2008. Multi-species recovery strategy for the Princeton Landscape, including dwarf woolly-heads (Psilocarphus brevissimus var. brevissimus), slender collomia (Collomia tenella), and stoloniferous pussytoes (Antennaria flagellaris) in British Columbia. Prepared for the B.C. Ministry of Environment, Victoria, BC. 28 pp.

Cover illustration/photograph

Terry McIntosh

Additional copies

Additional copies can be downloaded from the B.C. Ministry of Environment Recovery Planning.

Library and Archives Canada Cataloguing in Publication Data
Southern Interior Rare Plants Recovery Implementation Group.
Multi-species recovery strategy for the Princeton landscape, including Dwarf woolly-heads (Psilocarphus brevissimus var. brevissimus), Slender collomia (Collomia tenella), and Stoloniferous pussytoes (Antennaria flagellaris) in British Columbia [electronic resource]

(British Columbia recovery strategy series)

Available on the Internet.
Includes bibliographical references.
ISBN 978-0-7726-6016-9

1. Short Woolyheads (Plant)- British Columbia - Princeton Region. 2. Diffuse collomia - British Columbia - Princeton Region. 3. Antennaria flagellaris - British Columbia - Princeton Region. 4. Wildlife recovery - British Columbia - Princeton Region. 5. Rare plants - British Columbia - Princeton Region. 6. Endangered plants - British Columbia. I. British Columbia. Ministry of Environment.

QK203.S68 2008     583'.99     C2008-960121-1

Content (excluding photographs and illustrations) may be used without permission, with appropriate credit to the source.

Disclaimer

This multi-species recovery strategy has been prepared by the Southern Interior Rare Plants Recovery Implementation Group, as advice to the responsible jurisdictions and organizations that may be involved in recovering the species. The British Columbia Ministry of Environment has received this advice as part of fulfilling its commitments under the Accord for the Protection of Species at Risk in Canada, and the Canada – British Columbia Agreement on Species at Risk.

This document identifies the recovery strategies that are deemed necessary, based on the best available scientific and traditional information, to recover dwarf woolly-heads, slender collomia, and stoloniferous pussytoes populations in British Columbia. Recovery actions to achieve the goals and objectives identified herein are subject to the priorities and budgetary constraints of participatory agencies and organizations. These goals, objectives, and recovery approaches may be modified in the future to accommodate new objectives and findings.

The responsible jurisdictions and all members of the recovery team have had an opportunity to review this document. However, this document does not necessarily represent the official positions of the agencies or the personal views of all individuals on the recovery team.

Success in the recovery of these species depends on the commitment and cooperation of many different constituencies that may be involved in implementing the directions set out in this strategy. The Ministry of Environment encourages all British Columbians to participate in the recovery of stoloniferous pussytoes, slender collomia, and dwarf woolly-heads.

Top of Page


Recovery Team Members

Southern Interior Rare Plants Recovery Implementation Group
Ted Lea (co-chair) – Vegetation Ecologist, B.C. Ministry of Environment
Orville Dyer (co-chair) – Wildlife Biologist, B.C. Ministry of Environment
Harold Baumbrough – Biologist
Brenda Costanzo – Plants at Risk Biologist, B.C. Ministry of Environment
Pam Krannitz – Biologist, Environment Canada, Canadian Wildlife Service
Lisa Scott – Consultant/SOSCP Stewardship

Technical Contacts

Ron Hall – Osoyoos Indian Band

Top of Page

Author

Ksenia Barton

Top of Page

Responsible Jurisdictions

The British Columbia Ministry of Environment is responsible for producing a recovery strategy for dwarf woolly-heads, slender collomia, and stoloniferous pussytoes under the Accord for the Protection of Species at Risk in Canada. Environment Canada’s Canadian Wildlife Service participated in the preparation of this recovery strategy.

Top of Page

Acknowledgements

Ksenia Barton prepared this document on behalf of the Southern Interior Rare Plants Recovery Implementation Group. Lucy Reiss, Ted Lea, and Brenda Costanzo offered valuable comments and suggestions during the development of this report. The B.C. Conservation Data Centre provided most of the rare plant information. The structure of this report is based in part on those of other multi-species recovery strategies (authors: Mike Miller, Carrina Maslovat, Matt Fairbarns, George Douglas, and Shyanne Smith). The following people provided useful information and advice: Curtis Björk, Matt Fairbarns, Dave Fraser, Joyce Gould, Gordon Humphrey, Frank Lomer, Terry McIntosh, Jenifer Penny, Allison Sanger, Rolf Schmitt, Madelon Schouten, Thayne Tuason, and George Wooten (affiliations noted in the Contacts list). Terry McIntosh, James Reveal, Mark Turner, and Carol Witham provided photographs. Environment Canada funded the preparation of this document.

Top of Page

Executive Summary

This multi-species recovery strategy has been developed to guide the recovery of plant species at risk that occur in a landscape south of Princeton, BC. The target species at risk are dwarf woolly-heads, southern mountain population (Psilocarphus brevissimus var. brevissimus), slender collomia (Collomia tenella), and stoloniferous pussytoes (Antennaria flagellaris). These species’ ranges extend south into the western United States.

The area consists of approximately 5 km² and has been described as one of the most important rare plant sites in British Columbia. In addition to the three nationally endangered species that grow there, at least nine additional provincially rare plant species have also been found within the area. This document addresses the recovery of the three target species at risk, and also recommends the recovery of the associated ecosystem.

The site occurs at the western edge of the distribution of open shrub/grassland at that elevation. Big sagebrush (Artemisia tridentata) dominates the vegetation of the landscape, which also features scattered ponderosa pine (Pinus ponderosa) and Douglas-fir (Pseudotsuga menziesii) trees. The habitat features unusual soils, perhaps explaining the unique species assemblage that occurs at the site. Important microsites in the landscape include vernal pools; eroding slopes with spring seepage; and dry, eroded sandy ridge slopes.

The target species are at risk due to a number of broad categories of threats such as habitat loss or degradation, invasive alien species, changes in ecological dynamics or natural processes, and disturbance. Other threats include stochastic events (e.g., wildfires and sustained drought), climate change, and natural disasters. Main concerns are from resource extraction, habitat degradation from recreation and cattle grazing, invasive alien species, and biological factors including demography and genetics. Intrinsic limiting factors include limited dispersal, poor recruitment or reproduction, population fluctuations, inbreeding, and restricted range. The recovery of the three target species at risk is considered technically and biologically feasible.

The recovery goals for each of dwarf woolly-heads, slender collomia, and stoloniferous pussytoes are:

  1. To maintain population(s) with the current area of occupancy; and
  2. To maintain any newly located additional population(s).

The recovery objectives for each of dwarf woolly-heads, slender collomia, and stoloniferous pussytoes are:

  1. Increase protection[1] for all extant occurrences by 2012;
  2. Confirm the distribution of these three species and update population and distribution objectives as needed by 2011;
  3. Reliably determine population trends by 2012;
  4. Assess the severity of the main threats to the populations (habitat loss or degradation, exotic species, changes in ecological dynamics or natural processes) by 2012;
  5. Determine the ecological factors necessary for population maintenance by 2012; and
  6. Determine the feasibility and necessity of restoring populations in suitable habitat areas by 2012.

Broad strategies to address the threats and meet the recovery objectives include communication and outreach, habitat protection and stewardship, site management, inventory, monitoring, scientific research, and population enhancement.

Critical habitat cannot be identified at this time due to a lack of general and site-specific information about the habitat requirements of the species. It will be identified in a recovery action plan.

Recovery actions could affect the following socioeconomic sectors: private land development, petroleum natural gas exploration and extraction, coal exploration and extraction, livestock grazing, some agricultural management, and off-road vehicle recreation.The expected magnitude of these effects is unknown and will be further addressed in the recovery action plan.

The following knowledge gaps exist concerning the target species at risk which, if filled, could influence recovery planning and actions:

  • confirmation of the persistence of slender collomia individuals in Canada, in the form of reproducing individuals or a seed bank;
  • detailed characteristics and delineation of suitable habitat;
  • research on species biology including life history, demography, genetics, pollinators, and impacts of invasive species;
  • seed bank dynamics;
  • response to disturbances (current and projected);
  • effects of changes to hydrological regimes; and
  • effects of climate change.

An action plan will be drafted by April 2011.

Top of Page


Background

Introduction

This multi-species recovery strategy has been developed to guide the recovery of three plant species at risk that occur in a landscape south of Princeton, British Columbia (B.C.). The target species at risk are dwarf woolly-heads, southern mountain population (Psilocarphus brevissimus var. brevissimus) (henceforth referred to as dwarf woolly-heads), slender collomia (Collomia tenella), and stoloniferous pussytoes (Antennaria flagellaris) (status summarized in Table 1). All known occurrences of the target species at risk in B.C. are within the Princeton area, and the species face a number of common threats and limitations, including: the extraction of coalbed methane; the development of transportation, housing, recreation, and tourism infrastructure; and habitat degradation. General recovery approaches are outlined to reduce the risk of extirpation of the target species in Canada.

In addition to addressing the recovery of the three target species at risk, this recovery strategy recommends the recovery of the associated ecosystem. This habitat-based approach addresses not only the nationally endangered species that are present, but also aims to protect other non-target species within the landscape, including a number of provincially rare plant species (some of which are candidates for COSEWIC assessment; see Table 3).

This report starts with a description of the Princeton landscape, followed by detailed information about each target species. The multi-species approach addresses common threats and limitations, knowledge gaps, and actions already completed or underway. Finally, the recovery section outlines the recovery goals and objectives, and approach for recovery implementation. Nomenclature for species follows Douglas et al. (1998b, 1999).

Table 1. Summary of target species at risk addressed in recovery strategy.

SpeciesCOSEWIC statusDate of COSEWIC designationGlobal and provincial ranksa% of global range in Canada
Dwarf woolly-heads (Psilocarphus brevissimus var. brevissimus)EndangeredNov. 2003, confirmed 2006G4T4?
S1 (Red list)
<1%
Slender collomia (Collomia tenella)EndangeredNov. 2003G4?
S1 (Red list)
<1%
Stoloniferous pussytoes (Antennaria flagellaris)EndangeredMay 2004G5?
S1 (Red list)
<1%

Based on COSEWIC (2003a, 2003b, 2004, 2006), Douglas et al. (2003, 2004), Douglas and Penny (2003), and Natureserve (2007).

a For more information, see “Populations and distribution” section for each species.

The three species are found in the Similkameen watershed, in the Southern Interior of B.C. The Similkameen watershed, along with the South Okanagan watershed, has been recognized for its ecological importance as a biodiversity hotspot (SOSCP 2003). These watersheds act as species migration corridors between the dry grasslands of the B.C. Southern Interior and the sagebrush steppe areas of the western United States (SOSCP 2003).

Frank Lomer discovered the botanical importance of this landscape in 1997. Within an area that he describes as one of the most important rare plant sites in B.C., Lomer (pers. comm., 2005) documented several rare vascular plant species occurrences, some of which were the first discoveries in Canada (Douglas et al. 1998a). He delineated the area (approximately 5 km²) that he considered to be excellent rare plant habitat, based on the occurrence of provincially Red- and Blue-listed species.

Figure 1. Princeton location in B.C., indicated by a star.

Figure 1 is a map showing the location of Princeton, B.C, indicated by a star.

The target species at risk occurrences are located along Highway 3, near the town of Princeton, approximately 1 km west of the Similkameen River, and north of Whipsaw Creek. The landscape occurs in the gradual transition zone between the North Cascades Mountains and the Thompson Plateau (Holland 1964). This physiographic region is part of the Dry Ecodomain, Semi-arid Steppe-highland Ecodivision, also known as the Columbia Basin, of the western United States between the Sierras and the Rocky Mountains (SOSCP 2003).

The climate of the area is classified within the Interior Douglas-fir Okanagan very dry hot biogeoclimatic zone (IDFxh1; Lloyd et al. 1990). Climatic conditions in the IDFxh1 are continental, characterized by hot, dry summers, a fairly long growing season, and cool winters. The site occurs at the western edge of the distribution of open shrub/grassland at that elevation. Big sagebrush (Artemisia tridentata) with scattered ponderosa pine (Pinus ponderosa) and Douglas-fir (Pseudotsuga menziesii) trees dominates vegetation of the landscape (Douglas et al. 2004).

This small area not only provides habitat for these three nationally endangered species (populations summarized in Table 2) but also at least eight provincially rare plant species (Table 3). The B.C. Conservation Data Centre does not have any records of non-plant COSEWIC Red- or Blue-listed species for the area.

Table 2. Canadian population information for target species at risk.

SpeciesPopulationEst. popn. sizeLast. obs.Land tenureSource
Dwarf woolly-heads (Psilocarphus brevissimus var. brevissimus)Princeton 17200
± 500
2004privateB.C. CDC 2008
Princeton 211 775
2 patches
2004privateB.C. CDC 2008
Slender collomia (Collomia tenella)Princeton 3127*2003privateB.C. CDC 2008
Stoloniferous pussytoes (Antennaria flagellaris)Princeton 41.4 million**
± 100 000
11 subpopulations
2003privateB.C. CDC 2008
Princeton 55000
5 subpopulations
2003privateDouglas et al. 2004

* no plants observed in 2004 (B.C. CDC 2008)
** 2002 estimate

Table 3. Additional provincially rare species that occur in the Princeton area.

Common nameScientific nameProvincial statusSourceComments
  • Carolina meadow-foxtail
Alopecurus carolinianusS2 (Red list)B.C. CDC 20083 populations,
vernally moist meadows/pools
  • Close-flowered knotweed
Polygonum polygaloides ssp. confertiflorumS1 (Red list)B.C. CDC 2008Vernally wet meadow
  • Cusick’s paintbrush
Castilleja cusickiiS1 (Red list)B.C. CDC 2008Vernally moist meadow
  • Dark lamb’s-quarters
Chenopodium atrovirensS1 (Red list)B.C. CDC 2008On dry, eroding slope
  • Dwarf groundsmoke*
Gayophytum humileS2S3 (Blue list)B.C. CDC 2008 
  • Kellogg’s knotweed
Polygonum polygaloides ssp. kelloggiiS2S3 (Blue list)B.C. CDC 20083 populations,
vernally wet meadow, seep, and depression
  • Oniongrass*
Melica bulbosa var. bulbosaS2 (Red list)B.C. CDC 2008 
  • Valley sedge*
Carex vallicola var. vallicolaS1 (Red list)B.C. CDC 2008 

* Species potentially at risk in Canada; candidates for COSEWIC assessment (B.C. CDC 2005).

Important microsites in the landscape feature distinct soil moisture regimes:

  • vernal pools that support populations of the dwarf woolly-heads and other species that specialize on this type of microhabitat (Table 3);
  • eroding slopes with spring seepage followed by summer drying that provide habitat for stoloniferous pussytoes and other species (Table 3); and
  • dry, eroded sandy ridge slopes that support the single slender collomia population.

Top of Page

Dwarf Woolly-Heads

Species assessment information from COSEWIC

Date of assessment: April 2006

Common name (population): dwarf woolly-heads, southern mountain population

Scientific name: Psilocarphus brevissimus var. brevissimus

COSEWIC status: Endangered

COSEWIC Status history: Designated Endangered in November 2003. Renamed Dwarf Woolly-heads (Southern Mountain population) in April 2006 and designated Endangered. Last assessment based on an update status report.

Canadian occurrence: British Columbia

Reason for designation: An annual herb restricted to a very small range and present at only three small sites on private lands within the COSEWIC Southern Mountain Ecological Area of British Columbia. Population size is subject to extreme fluctuations in the number of mature individuals due to variation in precipitation levels. The population is at risk from such factors as increased land development in the region and land use practices.

Summary from COSEWIC (2006).

Description

Dwarf woolly-heads is an herb with 8–20 cm long branched, woolly-hairy stems that are prostrate and matted (dwarfed forms may have simple, erect stems) and have a short taproot (Figure 2). Stem leaves are opposite, lance-linear, lance-oblong, or lance-triangular, and whitish woolly-hairy. Leaves are 4–15 mm long and 1.5 mm wide. Basal leaves are lacking. The flower heads are disciform (round and flattened), and occur singly in leaf axils or at tips of branches. The heads lack involucres (circles of bracts surrounding the flower head), and have hooded and balloon-like receptacular bracts (carried on the receptacle) that are 2.5–4.0 mm long at maturity. Heads usually have 50–80 female flowers (rarely as few as 20 in dwarfed forms) (Douglas et al. 1998b).

Figure 2. Dwarf woolly-heads (Photo by Carol Witham).

Figure 2 is a photograph of Dwarf Woolly-heads.

Populations and distribution

In Canada, the dwarf woolly-heads reaches the northern limits of its range in southern British Columbia, Alberta, and Saskatchewan. In British Columbia, the species is restricted to the Similkameen Valley, south of Princeton (see Figure 1; Douglas et al. 1998a, 2003). In the Canadian prairies, dwarf woolly-heads occurs in the extreme southeastern corner of Alberta and the extreme southwestern corner of Saskatchewan (populations previously identified as Psilocarphus elatior; Douglas et al. 2001; J. Gould, pers. comm., 2005).

Globally, Psilocarphus brevissimus var. brevissimus is restricted to western North America. In the United States, the plant occurs in California, Idaho, Montana, Nevada, Oregon, Utah, Washington, and Wyoming (Cronquist et al. 1994).

In Washington State, dwarf woolly-heads is common in vernal pools on the Columbia Plateau (Björk and Dunwiddie 2004). The nearest known U.S. population to the individuals in B.C. is in Lincoln County, approximately 250 hundred kilometres to the south (Douglas et al. 2003). In Montana, dwarf woolly-heads is rare. The nearest known U.S. population to the Alberta–Saskatchewan populations is located near Great Falls, Montana, approximately 170 km to the southwest (Montana Natural Heritage Program 2005).

The global, national, and subnational conservation status of dwarf woolly-heads are as follows: globally G4T4? (apparently secure); in Canada, NNR (not yet assessed); in the United States, NNR (not yet assessed). In B.C., the species is ranked S1 (critically imperiled), and in Alberta, S2 (imperiled). In the United States, it was assessed in only Idaho, Montana, and Wyoming as S2. It has not yet been assessed in California, Nevada, Oregon, Utah, and Washington. Status is based on Natureserve (2007), COSEWIC (2003a), Vujnovic and Gould (2002), and Douglas et al. (2001).

Two populations of dwarf woolly-heads have been recorded in B.C. (Table 2) (B.C. CDC 2008). Population sizes of this annual herb are strongly tied to annual precipitation patterns (Bauder 2000). This is typical of vernal pool plants (Griggs and Jain 1983). The first population, “Princeton 1”, is separated into two patches. It increased in size from 450 plants in 2003 to approximately 7200 plants in 2004 (B.C. CDC 2008). The second population, “Princeton 2”, has fluctuated dramatically in size in recent years. In 1997, the population size was described as “a few thousand plants” and it increased to 10,000+ plants in 2000. By 2002, it had grown to “one to two million plants”. In 2003, a drought year, the population declined to “several hundred plants”. In 2004, the population size increased to 11 775 plants (B.C. CDC 2008).

Because this species was not known to occur in B.C. before 1997 (Douglas et al. 1998a), long-term trends are unknown. The species may have been overlooked in the past, possibly due to fluctuating population sizes of mature individuals due to its annual reproductive strategy. If this were the case, the trends in the population size and area of occupancy cannot be known.

Needs of dwarf woolly-heads

Habitat and biological needs
Dwarf woolly-heads grows in “dried beds of vernal pools” (Hitchcock and Cronquist 1973). Keeley and Zedler (1998) define vernal pools as “precipitation-filled seasonal wetlands inundated during periods when temperature is sufficient for plant growth, followed by a brief waterlogged-terrestrial stage and culminating in extreme desiccating soil conditions of extended duration.”

In B.C., populations of dwarf woolly-heads occur in vernal pools and at the edges of ephemeral ponds. Sites have calcareous clay bottoms; the soil is wet in the spring and dry, hard, and cracked in the summer (Douglas et al. 2003; F. Lomer, pers. comm., 2005). The vernal pools occur in large forest openings and are dominated by Scouler’s popcornflower (Plagiobothrys scouleri) and close-flowered knotweed (Polygonum polygaloides ssp. confertiflorum). Other species that occur near the vernal pools include one-spike oatgrass (Danthonia unispicata), tiny mousetail (Myosurus minimus), Carolina meadow-foxtail (Alopecurus carolinianus), lowland cudweed (Gnaphalium palustre), and annual hairgrass (Deschampsia danthonioides) (Douglas et al. 2003).

Dwarf woolly-heads is considered a vernal pool specialist (Schlising and Sanders 1982; Keeley and Zedler 1998; Bauder 2000). Dwarf woolly-heads’ tolerance of inundation allows the species to outcompete grassland perennials, while its tolerance of soil desiccation and heat during summer drought allows it to proliferate where aquatic/wetland species cannot (Bauder 2000). Experimental studies have demonstrated, however, that the species grows best in areas of bare ground or with less competition from other species (Moore et al. 2001).

This annual species is assumed to reproduce either by self-pollination (Douglas et al. 2003) or through asexual reproduction (Cronquist 1950). Keeley and Zedler (1998) recognize four stages in the annual vernal pool cycle: (1) a wetting phase; (2) an aquatic or inundation phase; (3) a waterlogged-terrestrial phase, and (4) a drought phase. In vernal pool species, germination is typically initiated during the wetting or inundation phases. Flowering is initiated during the transition to the waterlogged-terrestrial phase, which occurs in June in the Princeton area. Fruiting follows during the drought phase (Douglas et al. 2003).

This annual species relies on a seed bank for its persistence in vernal pool sites. The importance of the seed bank in allowing dwarf woolly-heads populations to rebound after disturbances has been illustrated experimentally (Cox and Austin 1990). Birds are the most likely agents of seed dispersal for the species over longer distances (Silveira 1998).

Top of Page

Slender Collomia

Species assessment information from COSEWIC

Date of assessment: November 2003

Common name: Slender collomia

Scientific name: Collomia tenella

COSEWIC status: Endangered

COSEWIC Status history: Designated Endangered in November 2003. Assessment based on a new status report.

Canadian occurrence: British Columbia

Reason for designation: An annual herb present at a single sandy site near Princeton, BC. The population fluctuates widely from year to year. At risk to stochastic events, roadside development, sand removal, and invasion by alien species.

Summary from COSEWIC (2003b).

Description

Slender collomia is an annual herb from a taproot, with ascending to spreading, freely branched stems up to 15 cm tall, with stalked glands at least on the upper part (Figure 3). The alternate, linear, entire leaves are 1–5 cm long and 1–5 mm wide. Flowers occur singly or in pairs along and at the ends of the branches (appearing to be borne in the forks of branches and in leaf axils). The corollas are pinkish to white and 4–6 mm long. The short corolla tubes spread to five lobes. The calyces are one-half to one-third as long as the corollas and they bow out, often forming purplish knobs at the sinuses. Calyces have 1–2 mm long triangular teeth. Capsules have one-seeded chambers that release seeds that become sticky when moistened (Douglas et al. [eds.] 1999).

Figure 3. Slender collomia (Photo by James L. Reveal).

Figure 3 is a photograph of Slender collomia

Populations and distribution

In Canada, slender collomia reaches the northern limit of its range in B.C., where it is rare. The plant is restricted to the Similkameen Valley, south of Princeton (see Figure 1; Douglas et al. 1998a; Douglas and Penny 2003).

Globally, slender collomia is restricted to western North America. In the United States, the plant occurs in Idaho, Nevada, Oregon, Utah, Washington, and Wyoming (Natureserve 2007).

In Washington State, slender collomia is uncommon, but widespread and localized. One population occurs along the Lost River Trail, near the confluence with the Methow River, in open conifer forest (G. Wooten, pers. comm., 2005). This population is approximately 70 km to the south of the Canadian population at the Princeton site. Washington populations of this species could theoretically contribute to a rescue effect for Canadian populations if the sticky seeds were transported by an animal or vehicle.

The global, national, and subnational conservation status of slender collomia is summarized as follows. Global status is G4? (apparently secure), national status in Canada is N1 (critically imperiled), and in the United States the status has not yet been assessed. Status in B.C. is S1 (critically imperiled). The rank in Utah is S2? (imperiled) and in Wyoming S3 (vulnerable). The status has not yet been assessed in Idaho, Nevada, Oregon, and Washington. Status is based on Natureserve (2007).

One population (Princeton Population 3) of slender collomia has been found in Canada (Table 2), but no individuals were observed in 2004 (B.C. CDC 2008). Long-term trends are unknown as this species was not known to occur in B.C. before 1997 (Douglas et al. 1998a). The population size of this annual species has been fluctuating in recent years (Table 4) (Douglas and Penny 2003; B.C. CDC 2008).

Table 4 . Slender collomia population sizes (1997–2004) (Douglas and Penny 2003; B.C. CDC 2008).

YearPopulation size
199710
20001
20020
2003127
20040
Needs of slender collomia

Habitat and biological needs
Douglas and Penny (2003) describe the B.C. habitat of slender collomia as:

“Eroded, steeply-sloped, southeast-facing sections of a sandy ridge. The sandy ridge, formed by fluvial processes during the last glaciation, consists of fine-textured sands. The eroded sections of the slopes are sparsely vegetated with about 20% cover.”

The associated vegetation includes the shrub saskatoon (Amelanchier alnifolia), as well as a variety of herbs: arrowleaf balsamroot (Balsamorhiza sagittata), timber milk-vetch (Astragalus miser), narrow-leaved collomia (Collomia linearis), thread-leaved phacelia (Phacelia linearis), silky lupine (Lupinus sericeus), Dalmatian toadflax* (Linaria genistifolia ssp. dalmatica), cheatgrass* (Bromus tectorum), and bluebunch wheatgrass (Pseudoroegneria spicata). Scattered Douglas-fir (Pseudotsuga menziesii) and ponderosa pine (Pinus ponderosa) trees occur on the ridge (Douglas and Penny 2003).

In Washington State, slender collomia grows along lightly disturbed trails and slopes in the lower montane zone. Habitats are similar to those of small-flowered blue-eyed Mary (Collinsia parviflora) and the wooded slopes, thickets, and open places where Great Basin nemophila (Nemophila breviflora) grows (Hitchcock et al. 1959; G. Wooten, pers. comm., 2005).

Other annual members of the Collomia genus are self-compatible and self-pollinating (Wilken 1993). Seeds are sticky when moistened and may, therefore, be animal-dispersed (Douglas and Penny 2003). This annual species relies on a seed bank for its persistence in sites.

Little is known about slender collomia habitats, and habitat needs of the species in Canada cannot be generalized.

Top of Page

Stoloniferous Pussytoes

Species assessment information from COSEWIC

Date of assessment: May 2004

Common name: Stoloniferous pussytoes

Scientific name: Antennaria flagellaris

COSEWIC status: Endangered

Status history: Designated Endangered in May 2004. Assessment based on a new status report.

Canadian occurrence: British Columbia

Reason for designation: A short-lived perennial plant present at only three geographically restricted localities occupying very small areas of specialized habitat of ephemerally moist seepage sites on private lands. It is at greatest risk from ATV use that currently is evident close to the populations. It may also be impacted by changes in ground water hydrology and surface impacts from increased development activities in the area such as the proposed production of coalbed methane.

Summary from COSEWIC (2004).

Description

Stoloniferous pussytoes is a short-lived perennial herb that grows from a fibrous root; its several simple, silky woolly-hairy, erect to ascending stems are 0.5–3.5 cm tall (Figure 4). The plant produces slender stolons up to 10 cm long that are naked (except for the tips). The unstalked basal leaves are linear to linear-oblanceolate, silky woolly-hairy, and 1–3 cm long by 0.5–2 mm wide. The stem leaves are similar, but are slightly reduced upwards. The flowers occur in solitary, terminal heads. Female involucres (circles of bracts surrounding the flower head) are 7–13 mm tall, with lanceolate, brown- or reddish-brown-tinged involucral bracts that are thinly woolly-hairy below. Male involucres are 4–7 mm tall, with translucent, brownish-tipped involucral bracts. Female flowers are 5–7 mm tall, while male ones are 3–4.5 mm tall. Fruits are warty, elliptic achenes that are 2–3 mm long. The 6–8 mm tall pappus (scales, bristles, or hairs at the apex of the seed) is white with hairlike bristles (Douglas et al. 1998b).

Figure 4. Stoloniferous pussytoes (Photo by Mark Turner).

Figure 4 is a photograph of Stoloniferous pussytoes

Populations and distribution

In Canada, stoloniferous pussytoes reaches the northern limit of its range in B.C., where it is rare. The plant is restricted to the Similkameen Valley, south of Princeton (see Figure 1; Douglas et al. 1998a, 2004).

Globally, the species is restricted to western North America. In the United States, the plant occurs in California, Idaho, Nevada, Oregon, Washington, and Wyoming (Cronquist et al. [eds.] 1994). In Washington State, stoloniferous pussytoes occurs widely but in locally common patches (G. Wooten, pers. comm., 2005). The nearest known U.S. population occurs approximately 70 km to the south of the Canadian populations, 8 km northeast of Mazama, WA, in red bed volcanic marine deposits (G. Wooten, pers. comm., 2005). This population of this wind-dispersed species may possibly contribute to a rescue effect for Canadian populations. Such a rescue effect was previously thought to be unlikely for because the nearest known U.S. location was as much as 190 km to the south of Canadian populations (Douglas et al. 2004).

The global, national, and subnational conservation status of stoloniferous pussytoes is as follows: global status is G5? (secure), and status in Canada and the United States is NNR (not yet assessed). In British Columbia, the species is ranked S1 (critically imperiled), in California, S3 (vulnerable), and in Wyoming, S1S2 (critically imperiled to imperiled). The status has not yet been assessed for Idaho, Oregon, and Washington, and is not listed as occurring in Nevada (NatureServe 2007).

Three Canadian populations of stoloniferous pussytoes were originally identified in the COSEWIC status report (Douglas et al. 2004). Since then, the B.C. Conservation Data Centre reinterpreted the population information and defined two populations for the species in Canada (Table 2; B.C. CDC 2008).). The first population, “Princeton 4”, consisted of approximately 1.4 million individuals in 11 subpopulations in 2003. The second population, “Princeton 5”, consisted of approximately 5000 individuals in 5 subpopulations in the same year. Although some populations have been visited more than once, short-term trends cannot be assessed due to different survey methods (B.C. CDC 2008).

As this species was not found in B.C. before 1997 (Douglas et al. 1998a), long-term trends are unknown. The species may have been overlooked in the past, possibly due to its occurring on private land, or because of fluctuating population sizes of mature individuals due to its short generation times, in which case the trends in the population size and area of occupancy are unknown.

Needs of stoloniferous pussytoes

Habitat and biological needs
In B.C., stoloniferous pussytoes populations occur in a matrix of level to gently sloping big sagebrush (Artemisia tridentata) shrub/grassland with scattered ponderosa pine (Pinus ponderosa) and Douglas-fir (Pseudotsuga menziesii). Stoloniferous pussytoes grows on moderate slopes with southerly aspects. The sites have a distinct hydrology, characterized by ephemeral winter seepage followed by drying in the early summer. The soil moisture regime is associated with erosion in the form of slow, downslope soil movement. As a result, the sites have exposed mineral soil and are sparsely vegetated (Douglas et al. 2004).

In Washington State, stoloniferous pussytoes is found “in dry rocky soils, open areas, vernal-wet in sagebrush-steppe” (Turner and Gustafson 2006).

The species is dioecious, with male and female structures on separate plants. Pollination is by wind, and seeds are produced sexually by outcrossing (Bayer 1996). The numerous hair-like bristles of the mature achenes facilitate its dispersal by wind. Plants also reproduce vegetatively by producing stolons that terminate in plantlets. Initially, the mother plant provides the plantlet with nutrients via the stolon. The genetically identical plantlets eventually become independent plants, as stolons are naturally severed over time. This mode of reproduction results in very restricted dispersal, as stolons only reach 10 cm long (Douglas et al. 1998b).

Genetically, some functional inbreeding has been observed in Oregon and California populations of the species. Those populations were found to have relatively high intra- and inter-population genetic diversity. The peripheral populations from California are not genetically differentiated from the central Oregon ones (Bayer 1990).

Based on habitats where the species has been observed in Canada and elsewhere, stoloniferous pussytoes appears to thrive on gently sloping sagebrush sites with vernally wet soils that dry out in summer. Vegetation cover tends to be low. Transplantation studies in California indicate that soil chemistry and characteristics may be important to the species’ habitat needs (Grant 1989, 1990).

Top of Page

Limiting Factors

Limited dispersal may explain the very small extent of occurrence of these three species at risk in Canada. Poor dispersal reduces the likelihood that populations will be bolstered by immigrant propagules, or that new populations will become established in suitable habitats.

Poor recruitment and reproduction and population fluctuations are limiting factors relevant to the persistence of slender collomia in Canada, as no reproducing individuals were found in 2004 and it is unknown whether individuals emerged in 2005. Unless plants germinate from the seed bank, the species will be extirpated in Canada. The duration of viability of seeds in the seed bank is unknown. Dwarf woolly-heads and stoloniferous pussytoes population sizes tend to fluctuate according to climatic conditions and poor recruitment/reproduction likely occur in drought years, though seed banking is expected to offset fluctuations to some degree in these annual/short-lived species.

As both species are assumed to reproduce by self-pollination, inbreeding poses a potential risk to the persistence of dwarf woolly-heads and slender collomia in Canada. Population genetic studies would be required to assess the degree of this concern. U.S. populations of stoloniferous pussytoes have exhibited some functional inbreeding as well (Bayer 1990). All three target species at risk have restricted ranges in Canada. Small or restricted ranges increase the likelihood of catastrophic events extirpating all occurrences of species in this jurisdiction.

Top of Page

Threats

These three species are at risk due to a number of current and potential threats and limitations. Table 5 summarizes the threats and their potential risks and effects on recovery. The threats are described in more detail in the following sections.

Table 5. Threats to habitat and survival of target species at risk.

ThreatPotential effect of threat on individual speciesPotential effect of threat on target species at risk
Dwarf woolly-headsSlender collomiaStoloniferous pussytoesNature of impact1Risk of threatPotential effect on recoveryBiological and technical potential to alleviate impactOverall threat priority2
Habitat Loss Or Degradation 
Resource extraction
  • Petroleum natural gas
highhighhighS, Hmed?highhighv. high
  • Coal
highhighhighS, Hlow?highhighhigh
Property development
Tourism and recreationhighhighhighS, Hmed?highhighv. high
ResidentialhighhighhighS, Hlow?highhighhigh
Recreational activities
  • Off-road vehicle use
highhighhighS, Hmed?highhighv. high
Grazingmed?low?low?S, Hhighlow?highhigh
Soil extraction/depositionhighhighhighS, Hlow?highhighhigh
Invasive Alien Species
Competitionlowmed?med?S, Hmed?med?lowlow
Use of non-specific herbicideshighhighhighShighhighhighhigh
Changes In Ecological Dynamics Or Natural Processes
Hydrological alterationshighlow?high?S, Hlow?highhighhigh
Secondary succession
  • Encroachment by native vegetation (due to fire suppression)
lowmed?med?Hlow?med?medlow
Stochastic events
  • Wildfires
med?med?med?Slow?high?lowlow
  • Sustained drought
med?low?med?Smed?high?nolow
Climate And Natural Disasters
Global climate changemed?low?med?S, Hmed?low?nov. low

1. S = impact on survival, H = impact on habitat
2. Based on scoring scheme:

  • overall score (v. high = 8–9, high = 7, medium = 6, low = 5, very low = 0–4) = score for risk of threat + score for potential effect on recovery + score for likelihood of success (high = 3, medium = 2, low = 1, no = 0)
Threat classification

Habitat loss or degradation
Resource extraction: Economically important coalbed methane resources underlie the Princeton habitats of the target species at risk (R. Schmitt, pers. comm., 2005; G. Humphrey, pers. comm., 2005). Extraction of those resources is perhaps the greatest threat facing the three species. Concerns associated with coalbed methane extraction include the clearing of large areas of vegetation for wells (approximately 1 ha; R. Schmitt, pers. comm., 2005), the disruption of groundwater with potential changes in surface hydrology (Smith 2005), potential pollution of surface waters (Smith 2005), vegetation disruption associated with access routes, and reclamation activities (which may involve disposing of “drill mud” over large areas; R. Schmitt, pers. comm., 2005).

Property development: While not necessarily imminent, the threat of habitat loss and degradation due to property development activities could be significant. Development activities could destroy species habitat, with effects essentially irreversible or requiring long-term recovery or mitigation.

Recreational activities: In 2002, field surveyors observed evidence of all-terrain vehicle and dirt bike use near the sites. For example, some tracks passed within several metres of the “Princeton 4” population of stoloniferous pussytoes (Douglas et al. 2004). The lack of fences (except on the south side) allows for easy access to the area. Seasonally moist or wet microsites are most at risk from vehicle damage. Soil disturbance and rutting could alter the soil moisture regime or alter the pattern of erosion, either of which could contribute to the degradation of target species at risk habitats (Douglas et al. 2004). A study of vernal pool ecosystem invasibility has demonstrated that vehicle disturbance promotes the proliferation of invasive alien species in those habitats (Björk 2005).

Grazing: Cattle grazing poses a potential threat of habitat degradation, primarily by the mechanisms of soil compaction, mechanical damage of microbiotic crusts, and physical alteration of habitats (Kauffman and Krueger 1984; Elmore 1992; van Woudenberg 1999). Cattle heavily trampled the “Princeton 1” population of dwarf woolly-heads at the site in the past (B.C. CDC 2008). Findings from studies designed to assess the impacts of grazing on vernal pool systems have typically been inconclusive and contradictory. For example, impacts on plant species can vary significantly depending on the timing of grazing (Borgias 2004). Grazing can control vigorous growth of vegetation which can stifle germination. On the other hand, cattle grazing has been demonstrated to increase the proliferation of alien species in vernal pool ecosystems (Björk 2005). Slender collomia and stoloniferous pussytoes grow in sparsely vegetated microsites and do not seem to be affected by cattle activities (F. Lomer, pers. comm., 2005).

Soil extraction/deposition: Potential soil removal or deposition would also contribute to habitat degradation, through changes in soil characteristics or soil nutrient regime. This type of disturbance is not known to be an imminent threat.

Changes in ecological dynamics or natural processes
Hydrological alteration: Changes in hydrology represent a potential threat to target species at risk, and to dwarf woolly-heads in particular. Drilling of wells, irrigation systems, roads, soil removal or fill, and stream diversions all have the potential to alter the hydrological regimes of the microsites that support the target species at risk, resulting in habitat degradation that could contribute to population decline. Off-site activities can thus have significant detrimental effects on target species at risk habitats.

Secondary succession: Encroachment by native vegetation through secondary succession is not known to affect these three target species at risk populations, but is a potential risk.

Stochastic events: Due to the small ranges of the target species at risk in Canada, catastrophic stochastic events such as severe wildfires or sustained droughts could result in the extirpation of the species in Canada.

Invasive alien species
Invasive alien species are not known to be a serious threat to target species at risk populations currently, but they represent a potential threat. The B.C. Ministry of Agriculture and Lands has designated 21 plant species as “noxious weeds” in the South Okanagan–Similkameen (SOSCP 2003). Many other invasive alien species also occur in the area. The proliferation of invasive species can degrade habitat through competitive exclusion of native species.

Weed control activities also constitute a threat to target species at risk. Under the Weed Control Act, an occupier must control noxious weeds growing or located on land and premises (Province of British Columbia 2004). Marginally specific chemical weed control substances that kill broad-leaved plant species would likely kill individuals or populations of species at risk. The risk of this occurring is generally low, except along the transmission corridor, where the risk is higher.

Climate and natural disasters
Climate change, a potential threat to target species at risk populations, could result in population declines, because the species are already growing in marginal climatic conditions at the northernmost extents of their ranges. Climate change could also have detrimental effects on metapopulation dynamics if peripheral populations become increasingly isolated due to loss of habitat in the centers of species’ ranges.

Top of Page

Actions Already Completed or Underway

A broad range of organizations and programs are currently involved in the conservation of natural biodiversity of the South Okanagan and lower Similkameen watersheds (see SOSCP 2003 for more detail). Recovery work is intended to build on these efforts. Recovery actions specific to the target species at risk have yet to begin, although some landowner contact has been initiated.

Top of Page

Knowledge Gaps

Knowledge gaps exist concerning the target species at risk which, if filled, could influence recovery planning and actions. They include:

  • confirmation of the persistence of slender collomia individuals in Canada, in the form of reproducing individuals or a seed bank;
  • detailed habitat characteristics and delineation of suitable habitat;
  • research on species biology including life history, demography, genetics, pollinators and impacts of invasive species;
  • seed bank dynamics;
  • response to disturbances (current and projected);
  • effects of changes to hydrological regimes; and
  • effects of climate change.

Top of Page


Footnotes – Part 2

* Non-native species.

1 This may involve protection in any form including stewardship agreements and conservation covenants on private lands; land use designations on Crown lands; and protection in federal, provincial, and local government protected areas.