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Recovery Strategy for Multi-Species at Risk in Garry Oak Woodlands in Canada (Proposed)


1. Introduction

This strategy has been developed under the broader Recovery Strategy for Garry Oak and Associated Ecosystems and their Associated Species at Risk in Canada: 2001-2006 (GOERT 2002) to address the recovery of five plant species at risk that occur within Garry oak (Quercus garryana) woodland habitat: deltoid balsamroot (Balsamorhiza deltoidea), white-top aster (Sericocarpus rigidus), small-flowered tonella (Tonella tenella), Howell's triteleia (Triteleia howellii), and yellow montane violet (Viola praemorsa ssp. praemorsa). In particular, this strategy comprises components of Strategic Approach D: "Protection and recovery of species at risk" of the GOERT strategy. This strategy covers all locations of all five of these species within Canada.

General background information that is common to all species is provided in Section A of the GOERT 2002 strategy and includes common habitat elements and background on Garry oak and associated ecosystems recovery.

The Garry Oak Woodlands Recovery Strategy provides two components of the three tiers of recovery identified by the Garry Oak Ecosystems Recovery Team (GOERT). In Section 2, key characteristics of the species, importance to people, threats to the species and habitat, critical habitat and recovery of the species are discussed. Section 3 provides detail on each species' biological needs and habitat requirements.

Table 1. Species addressed in this Recovery Strategy2
Species NameCOSEWIC StatusProvincial Rank and ListingGlobal RankSARA Status (Schedule 1)Estimated PopulationPercent Range in Canada
deltoid balsamroot
(Balsamorhiza deltoidea)
EndangeredS1 - RedG5Endangered~ 1160 plants< 1%
white-top aster
(Sericocarpus rigidus)
ThreatenedS2 - RedG3Threatened~ 54,800 – 94,800 stems~ 15%
small-flowered tonella
(Tonella tenella)
EndangeredS1 - RedG5Endangered~ 236-316 plants< 1%
Howell's triteleia
 (Triteleia howellii)
EndangeredS2 - RedG5Endangered~ 1000 plants< 1%
yellow montane violet
(Viola praemorsa ssp. praemorsa)
ThreatenedS2 - RedG5T3T5Threatened~ 45,000 plants< 1%

2 Taxonomy and nomenclature follows Douglas et al. (1998a, 1998b, 1999a, 1999b and 2001).

See Appendix 2 of the Recovery Strategy for Garry Oak and Associated Ecosystems for definitions of ranks and listings used in this table.

1.1 Stewardship Approach

For successful implementation in protecting species at risk there will be a strong need to engage in stewardship on a variety of land tenures, and in particular on private land and on Indian Reserves. Stewardship involves the voluntary cooperation of landowners to protect Species at Risk and the ecosystems they rely on. It is recognized in the Preamble to the federal Species at Risk Act (SARA) 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." It is recognized in the Bilateral Agreement on Species at Risk, between British Columbia and Canada 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."

1.2 Stewardship Approach for Private Lands

Since many species of risk occur only or predominantly on private lands, including some of the species in this strategy, stewardship efforts will be the key to their conservation and recovery. It is recognized that to successfully protect many species at risk in British Columbia there will have to be voluntary initiatives by landowners to help maintain areas of natural ecosystems that support these species of risk. This stewardship approach will cover many different kinds of activities, such as: following guidelines or best management practices to support species at risk; voluntarily protecting important areas of habitat on private property; conservation covenants on property titles; ecogifting part or all of their property to protect certain ecosystems or species at risk; or to sell their property for conservation. For example, both government and non-governmental organizations have had good success in conserving lands in the Province. This could be aided by the B.C. Trust for Public Lands.

1.3 Description of the Habitat Area Covered by the Recovery Strategy

The species covered in this strategy mostly occur in association with Garry oak woodlands in Canada. Garry oak woodlands, for the purposes of this strategy, range from open parkland with scattered Garry oak trees, a sparse shrub layer and a diverse herb layer, to closed Garry oak woodlands, sometimes including arbutus (Arbutus menziesii) and Douglas-fir (Pseudotsuga menziesii) trees, with a patchy mix of shrub thickets and meadow openings. These woodlands occur as patches within the Coastal Douglas-fir biogeoclimatic zone as a result of climatic, edaphic, and cultural factors (see Fuchs 2001).

Annual precipitation in Victoria, the centre of historical Garry oak woodland distribution in Canada, is approximately 600 mm (based on climate normals 1971-2000, Environment Canada 2004). Annual precipitation increases toward the periphery of Garry oak woodlands, approaching 1000 mm in Metchosin and up to 1500 mm in Duncan. The majority of this rainfall occurs in winter, with only approximately 45-65 mm per month falling in May-August in Duncan and 20 mm or less during this period in Victoria.

Soils supporting Garry oaks on southeastern Vancouver Island are often gravelly loams or gravelly sandy loams (Stein 1990). These soils are often shallow (i.e. <30 cm), with depths ranging from a few to over 100 cm, with deeper soils typically being very well-drained (Fuchs 2001, Roemer 1993). Soils can also be nitrogen poor, resulting in less competition from other native species.

It is likely that Garry oak woodlands had a more extensive range in Canada several thousand years ago as suggested by pollen in soil cores sampled on southern Vancouver Island and the adjacent mainland (R. Hebda pers. comm.; Brown and Hebda 2002, Pellat et al. 2001). The use of fire by First Nations is thought to have allowed the oak woodlands to persist and perhaps expand on southeastern Vancouver Island, particularly in areas with deeper soil, by preventing conifer encroachment as the climate became wetter (Pellat et al. 2001, Fuchs 2001, Turner 1999, Thilenius 1968).

There is little intact Garry oak woodland ecosystem left and most of the remaining stands contain an abundance of invasive, often introduced, species (MacDougall et al. 2004). In urban areas, veteran oaks remain, however, the understory has mostly been replaced by cultivated lawns and pavement. Remaining woodland patches are highly disjunct, typically small, and are most often dominated by invasive plant species. In addition, ecosystem processes (such as fire, herbivory, and hydrology) are often altered.

The remnants of Garry oak woodland habitats in which the species in this strategy are found vary between sites and do not necessarily represent typical or historical habitat conditions. Historically, Garry oak woodlands have been described as occurring in two major forms: oak parklands typified by richer, deeper soils with an understory mosaic of shrubs and herbaceous meadows, and drier scrub oak ecosystems on rocky hillsides and shorelines with poorer, shallower soils and a sparser understory (MacDougall et al. 2004). The species within this strategy typically occur in one of these woodland types, however, the majority of the habitat has been heavily invaded by exotic species, and community structure and composition has been altered by fire suppression. One deltoid balsamroot population (Tyee Spit) does not have a Garry oak overstory. One common factor in all of the sites is that they experience seasonal drought and/or have well-drained soils.

1.4 Rationale for Multi-species Approach to Recovery

Habitat protection plays an essential role in the conservation of wildlife species, as noted in the federal Species At Risk Act (SARA). GOERT has recognized this in their broad and fine filter approach to recovery planning, as discussed in the umbrella strategy (GOERT, 2002). A number of other important considerations identified by the National Recovery Working Group (2001) also indicate a need to approach species-specific recovery of Garry oak woodland species from a habitat perspective:

  • These species at risk occupy a limited geographical area and their recovery actions must be integrated at some point in the planning process.
  • These species may have conflicting needs which can be identified and addressed proactively with ecosystem and habitat approaches.
  • Some threats to these species, such as invasive species, operate at an ecosystem scale and are therefore more effectively tackled with an ecosystem or habitat-wide approach.

Populations of species at risk in Garry oak woodlands are at the northern limit of their range (Ceska 1992, Pojar 1980) and may face similar important genetic and other recovery issues as a result.

Finally, due to the large number of species at risk (approximately 100 species) that occupy Garry oak ecosystems, recovery planning at the ecosystem and habitat levels enables a highly integrated and efficient planning process.