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Recovery Strategy for the Island Blue* (Plebejus saepiolus insulanus) in Canada (Proposed)


Appendix 1. Recovery

Recovery Feasibility

Recovery is “the process by which the decline of an endangered, threatened or extirpated species is arrested or reversed, and threats removed or reduced to improve the likelihood of the species persistence in the wild. A species will be considered recoveredwhen its long-term persistence in the wild has been secured” (Environment Canada et al. 2005). Recovery of Greenish Blue insulanus subspecies depends upon the location of at least one population, eliminating threats to this population, and otherwise ensuring its survival.

As with many other rare species, little is known about the historical distribution of Greenish Blue insulanussubspecies. Nothing indicates that this subspecies was ever abundant or widespread in British Columbia. No data exist on the habitat and ecology of this subspecies and population viability cannot be estimated.

Canadian lepidopterists recognize Greenish Blue insulanus subspecies as a separate subspecies confined to southeastern Vancouver Island (Layberry et al. 1998; COSEWIC2000; Guppy and Shepard 2001). In the United States, Scott (1986) shows the subspecies P. saepiolus insulanus as being more widespread and having a range from northwestern California to southwestern B.C. (Vancouver Island only), Montana, Colorado, Nevada, and Utah. Hinchliff (1994) applies P.saepiolus insulanus to a few populations that occur only within Oregon. Until the taxonomic uncertainty surrounding the butterfly can be resolved, Greenish Blue insulanussubspecies is recognized as a distinct subspecies occurring only on Vancouver Island and found nowhere else in Canada (COSEWIC2000). Recovery of Greenish Blue insulanus subspecies is not currently feasible as there are no known populations of the subspecies. If a population is found, recovery could be possible through the current framework for species protection in British Columbia.

Are individuals capable of reproduction currently available to improve the population growth rate or population abundance?
No population of Greenish Blue insulanus subspecies is known. Should a population be located, successful reproduction is implied. The capability of such a population to serve as a source to repopulate unoccupied habitat is unknown. Little information exists on population structure, dispersal and reproductive capability of this subspecies.

Is sufficient habitat available to support the species or could it be made available through habitat management or restoration?
Habitat and host information for Greenish Blue insulanussubspecies is scarce; few museum specimens exist and the most recent record is 1979. Because of this, the true extent of existing suitable habitat cannot be determined. General habitat and host information can be inferred from available data for other subspecies of the Greenish Blue. Locating a population of Greenish Blue insulanus subspecies would permit determination of details of habitat and host requirements.

Can significant threats to the species or its habitat be avoided or mitigated through recovery actions?
Much of the range of Greenish Blue insulanus subspecies falls within a densely populated area of British Columbia and habitat threats within that area (e.g., development pressure, invasive species) are expected to continue. At higher elevations, development pressure is less of a threat, although forestry may occur in adjacent habitats (e.g., road building through potential Greenish Blue insulanussubspecies habitat). Habitat threats may be mitigated through stewardship agreements with private landholders, working with local governments and industry on provincial Crown lands managed for resource extraction, and/or other measures.

Do the necessary recovery techniques exist and are they known to be effective?
If a population of the subspecies is found, effective recovery techniques exist and may be successful. Captive breeding of Greenish Blue insulanus subspecies to gain life history and reproduction knowledge and supplement wild populations may be feasible. Techniques potentially used in the recovery of this subspecies would be similar to the techniques applied to species with similar threats, issues, and requirements: captive breeding, invasive species control, host plant propagation. However, all threats to survival of this subspecies must be mitigated first and some may preclude successful recovery.

Recovery Goal

The recovery goal is to confirm the presence or absence of Greenish Blue insulanus subspecies within the species historic range in Canada, and protect1 any extant population(s) if found.

Recovery Objectives

  • To survey all historical sites and areas of potential habitat and locate any existing population(s) of Greenish Blue insulanus subspecies by 2017.
  • To implement habitat protection1 and threat mitigation for any populations located by 2017, using stewardship activities and other mechanisms.

Approaches Recommended to Meet Recovery Objectives

Potential threats include invasive species encroachment, habitat destruction, recreational habitat use, Btk spraying, climate change, and collecting (Table 1). The broad strategies to address the threats are as follows (II – III strategies apply should a population be located):

  1. Inventory – survey historic locations and additional suitable habitat.
  2. Site protection – protect1 any extant populations and their habitats if the species is relocated in British Columbia.
  3. Clarify taxonomic uncertainty within the Plebejus saepiolus subspecies group.
  4. Research and monitoring - conduct research on populations, habitats, and potential threats; identify the real threats by establishing a monitoring program for known and potential threats and to monitor changes in population attributes and habitats.

Recovery Planning Table

Table 1. Recovery Planning Table
PriorityObj. no.Threats addressedRecommended approaches to meet recovery objectives
HighI–III–III
  • Draft an Inventory Strategy for Greenish Blue insulanus subspecies, a document that describes a scheduled approach to surveying historically occupied sites and areas of potential habitat for Greenish Blue insulanus subspecies, including procedures for long-term monitoring of any newly found populations.
  • Within the Inventory Strategy for Greenish Blue insulanus subspecies, identify and record potential threats at each historic location.
  • Create a habitat map for the likely range of Greenish Blue insulanus subspecies, showing the distribution of potential food plants and habitats on Vancouver Island.
LowI–III–VI
  • Develop a public education program on butterfly species at risk and the threats to these species, in conjunction with the Garry Oak Ecosystems Recovery Team public education program.
  • Develop an approach to establishing stewardship agreements, covenants, or other relevant partnerships with private owners of suitable Greenish Blue insulanus subspecies habitat
  • Identify the invasive species that may further threaten the subspecies.
  • Support further research into the threats to Greenish Blue insulanus subspecies
  • Clarify taxonomic status and uncertainty around Greenish Blue insulanus subspecies and its relationship to additional subspecies
  • Support long-term butterfly monitoring within the gypsy moth spray zone.

Performance Measures

Criteria for evaluating progress towards achieving the goals and objectives of this strategy include the following (III–V assume populations are located):

  • Clarification of the taxonomic relationship between subspecies in the Plebejus saepiolus subspecies group.
  • Confirmation of the presence or absence of the subspecies in Canada.
  • The percentage of recovery habitat sites that are under some form of effective protection. The number of stewardship agreements and/or covenants in place on private lands, or other measures on Crown land.
  • The initiation and progress of research projects on existing populations, habitats, understanding of threats, determination of ecological and habitat requirements, establishment of a monitoring program.
  • The number of educational and stewardship activities conducted with landowners and land managers.

Critical Habitat

Identification of the species' critical habitat

No critical habitat, as defined under the federal Species at Risk Act [S.2], is proposed for identification at this time. The critical habitat for Greenish Blue insulanussubspecies cannot be defined. The subspecies was last recorded in 1979 and specific habitat information is not available. If a population of the subspecies is found, a detailed definition of Greenish Blue insulanus subspecies critical habitat will be prepared according to a schedule of studies (Table 2).

Recommended schedule of studies to identify critical habitat

Table 2. Schedule of studies
Description of activityOutcome/RationaleTimeline
  • Survey all historical locations of Greenish Blue insulanus subspecies.

If a population is located, record habitat information and compile critical habitat description.

Better understanding of habitat requirements.

2017
  • Create an inventory strategy for the entire range of Greenish Blue insulanus subspecies, including mapping the distribution of potential host plants and habitats on Vancouver Island where the subspecies could occur.
  • Initiate an inventory of priority potential new habitat (excluding historical sites where records are from).
  • Within the potential habitat, identify suitable habitat that meets the needs for survival and recovery of the species if it is relocated.

If a population is found, record habitat information and compile critical habitat description.

Possible new populations located; better understanding of habitat requirements.

2010

Existing and Recommended Approaches to Habitat Protection

If a population of Greenish Blue insulanus subspecies is found, the habitat should be a priority for protection. If the habitat is private land, landowner contact should be initiated and best management practices should be made available to the landowner. If the habitat is Crown owned, legislative protection measures should be implemented. If the land is regional or municipally owned, contact these governments and make best management practices available.

For successful implementation of species at risk protection measures, there is a strong need for engaging stewardship activities on a variety of land tenures, including private and First Nations lands. Stewardship involves voluntary cooperation of landowners to protect Species at Risk and the ecosystems they rely on. The Preamble to the federal Species at Risk Act states that “stewardship activities contributing to the conservation of wildlife species and their habitat should be supported” and that “all Canadians have a role to play in the conservation of wildlife in this country, including the prevention of wildlife species from becoming extirpated or extinct.” Furthermore, the Bilateral Agreement between British Columbia and Canada on Species at Risk states that “stewardship by land and water owners and users is fundamental to preventing species from becoming at risk and in protecting and recovering species that are at risk” and that “cooperative, voluntary measures are the first approach to securing the protection and recovery of species at risk.”

Effects on Other Species

Recovery efforts for Greenish Blue insulanus subspecies will benefit all native butterfly species that occur within the same habitat through inventory, habitat conservation, restoration, and invasive species removal. Effects on other species will be assessed as recovery work is undertaken, assuming Greenish Blue insulanus subspecies populations are located.

Socio-economic Considerations

No social or economic considerations are evident as populations of Greenish Blue insulanus subspecies are not known to exist. If the species is relocated, a socio-economic analysis could be conducted; there is currently no reason to believe there would be significant impacts.

Statement on Action Plans

Pending the discovery of new occurrences of Greenish Blue insulanus subspecies during the planned inventory, the recovery goals and objectives for the subspecies will be redefined, and an action plan will be completed within five years of the date of the revised recovery strategy.


1 Protection can be achieved through a variety of mechanisms including: voluntary stewardship agreements, conservation covenants, sale by willing vendors on private lands, land use designations, and protected areas.