Golden paintbrush (Castilleja levisecta) COSEWIC assessment and status report: chapter 11

Technical Summary

Castilleja levisecta Greenman

golden paintbrush – castilléjie dorée

Range of Occurrence in Canada:

British Columbia

Extent and Area information

Extent of occurrence (EO) (km²) :

2.2 km² but historically likely only 100 km²

specify trend (decline, stable, increasing, unknown) :

stable over past 10 years

are there extreme fluctuations in EO (> 1 order of magnitude)?

no

area of occupancy (AO)

[Actual area occupied is about 0.039 km² but AO is 2 km² if a 1x1 km grid is used and 4 km²if a 2x2 km grid is applied] : maximum of 4 km²

specify trend (decline, stable, increasing, unknown) :

historic declines and 1 recent loss

are there extreme fluctuations in AO (> 1 order magnitude)?

no

number of extant locations :

2

specify trend in # locations (decline, stable, increasing, unknown) :

stable

are there extreme fluctuations in # locations (>1 order of magnitude)?

no

habitat trend: specify declining, stable, increasing or unknown trend in area, extent or quality of habitat :

declining in quality

Population information

generation time (average age of parents in the population) (indicate years, months, days, etc.) :

unknown, probably several years

number of mature individuals (capable of reproduction) in the Canadian population (or, specify a range of plausible values) :

currently < 3,400

total population trend: specify declining, stable, increasing or unknown trend in number of mature individuals :

decline

if decline, % decline over the last/next 10 years or 3 generations, whichever is greater (or specify if for shorter time period) :

25% over last 10 years

are there extreme fluctuations in number of mature individuals (> 1 order of magnitude)?

no

is the total population severely fragmented (most individuals found within small and relatively isolated (geographically or otherwise) populations between which there is little exchange, i.e., < 1 successful migrant / year)?

yes

list each population and the number of mature individuals in each :

  • Trial Island: 3,192
  • Alpha Islet: 169

specify trend in number of populations (decline, stable, increasing, unknown) :

stable over past 10 years

are there extreme fluctuations in number of populations (>1 order of magnitude)?

no

Threats (actual or imminent threats to populations or habitats)

  1. Threats to habitat: habitat degradation due to invasive species, altered fire regimes resulting in spread of shrubs and trees
  2. Threats to populations: mowing, herbivory, trampling

Rescue Effect (immigration from an outside source)

Low

does species exist elsewhere (in Canada or outside)?

yes

status of the outside population(s)?

globally critically imperiled

is immigration known or possible?

probably a very rare event

would immigrants be adapted to survive here?

likely

is there sufficient habitat for immigrants here?

yes

Current Status

COSEWIC : Endangered (May 2000), Endangered (Nov. 2007)

Status and Reasons for Designation

Status: Endangered

Alpha-numeric code: B1ab(iii,v)+2 ab(iii,v)

Reasons for Designation: The species is a perennial hemiparasitic herb of maritime meadows found within the Garry oak ecosystem of southeastern Vancouver Island. The species has lost most of its historic populations, having once been known from 7 locations. One small population was extirpated in recent years. The species is presently reduced to two populations on two small islands in the Victoria area. The spread of invasive alien plants continues to place the species at risk on Trial Island.

Applicability of Criteria

  • Criterion A (Declining Total Population): Not applicable. Decline in last 10 years only 25%.
  • Criterion B (Small Distribution, and Decline or Fluctuation): Meets Endangered B1ab(iii,v)+2ab(iii,v) due to the very small extent of occurrence and area of occupancy of the 2 remaining populations with continued loss of habitat quality and mature individuals.
  • Criterion C (Small Total Population Size and Decline): Meets Threatened C1 with a population size >2,500 but <10,000 mature plants and a decline of 25% in the past 10 years.
  • Criterion D (Very Small Population or Restricted Distribution): Meets Threatened D2 based on the occurrence of only 2 populations with an area of occupancy of <20km².
  • Criterion E (Quantitative Analysis): None available.

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