Multi-species at risk in maritime meadows (garry oak ecosystems) recovery strategy: chapter 2

1. Introduction

This strategy has been developed to address the recovery of seven plant and two butterfly species and their associated habitats (Table 1). These species are all characterized by one or more of the following: total population decline, small distributions with decline or fluctuation, loss of habitat, declining small population sizes or very small populations or restricted distribution (COSEWIC 2003b). Unless recovery actions are initiated, these species may become extinct or extirpated from Canada.

This recovery strategy is compatible with the federal Species at Risk Act (SARA). The strategy has been prepared using COSEWIC (Committee on the Status of Endangered Wildlife in Canada) status reports and is designed to guide the development of an Action Plan.

All of the species addressed in this strategy live almost exclusively within Garry oak and associated ecosystems. This strategy addresses both the specific needs of the target species as well as the plant communities and ecosystems where the species occur. The strategy constitutes one component of the recovery program for Garry oak and associated ecosystems as outlined in the Recovery Strategy for Garry Oak and Associated Ecosystems and their Associated Species at Risk in Canada: 2001-2006 (GOERT 2002). In particular, this strategy expands upon Strategic Approach D: “Protection and recovery of species at risk” of the umbrella GOERT strategy. This habitat-based, multi-species strategy for maritime meadow species is nested in the larger ecosystem-level recovery planning addressed by GOERT. It includes species-level planning as well as planning for the common habitat of the maritime meadow species.

The first section of this recovery strategy provides general background information common to all species, including common habitat elements, key characteristics of the species and the rationale for taking a multi-species approach to recovery. Section B addresses common threats and the identification of critical habitat. Section B also includes recovery goals, objectives and approaches for all species and for maritime meadow ecosystems. Section C describes each species, including their distribution, habitat and biologically limiting factors.

All nomenclature for plants follows the Illustrated Flora of British Columbia by Douglas et al. (1998a, b; 1999a, b; 2000; 2001a, b; 2002). The nomenclature for butterflies follows Butterflies of British Columbia by Guppy and Shepard (2001), which includes a subspecific reference for the island marble (Euchloe ausinoides ssp. insulanus) and differs from the nomenclature (Euchloe ausinoides) used by COSEWIC and SARA.


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 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.

 

Table 1: Species addressed in this recovery strategy
Species SARA Status
(Schedule 1)
COSEWIC status Date Designated BC DC RankFootnote a
Island marble Euchloe ausonides insulanus Extirpated Extirpated May 2000 G1T1
SX
Taylor’s checkerspot Euphydryas editha taylori Endangered Endangered Nov 2000 G1T1
SH
Bearded owl-clover Triphysaria versicolor ssp. versicolor Endangered Endangered May 2000 G5T5
S1
Bear’s-foot sanicle Sanicula arctopoides Endangered Endangered May 2001 G5
S1
Coastal Scouler’s catchfly Silene scouleri ssp. grandis Consultations Phase Endangered May 2003 G5TNR
S1
Golden paintbrush Castilleja levisecta Endangered Endangered May 2000 G1
S1
Prairie lupine Lupinus lepidus var. lepidus Endangered Endangered May 2000 G5
S1
Purple sanicle Sanicula bipinnatifida Threatened Threatened May 2001 G5
S2
Seaside birds-foot lotus Lotus formosissimus Endangered Endangered May 2000 G5
S1

COSEWIC uses the following definitions:
Extinct: A species that no longer exists.
Extirpated: A species that no longer exists in the wild in Canada, but occurs elsewhere.
Endangered: A species facing imminent extirpation or extinction.


1.3 Habitat area covered by the recovery strategy

All of the species covered in this recovery strategy are limited in their Canadian distribution to areas within the range of Garry oak and associated ecosystems. All of the Canadian occurrences of species covered in this recovery strategy are at the northern limit of their distribution and their ranges extend south into the United States. The Canadian populations of some of the species addressed in this strategy are widely disjunct from their main ranges in the United States (Table 2).

 

Table 2: Canadian population size and global percentages
Species Percentage of global population in Canada Estimated Total PopulationFootnote a.1
Island marble Less than 1% 0
Taylor’s checkerspot Less than 1% ~ 15
Bearded owl-clover Less than 1% 8 300-9 000
Bear’s-foot sanicle Less than 1% ~7 500
Coastal Scouler’s catchfly Less than 1% 400-540
Golden paintbrush 15% ~10 500
Prairie lupine Less than 1% ~115
Purple sanicle Less than 1% ~4 000
Seaside birds-foot lotus Less than 1% 400-600

The restricted Canadian range of these species is characterized by mild winters and dry, cool summers. In the winter, relatively warm, low-pressure systems dominate. January, the coldest month, has a daily mean temperature of 4.6° C and a mean daily minimum of 2.5° CFootnote 3 (Environment Canada 2003). December, the wettest month, receives an average of 108 mm of precipitation, including very little snow (Environment Canada 2003). In the summer, a large semi-permanent high-pressure area extends over the northeastern Pacific. May, June, July and August each bring less than 25 mm of mean monthly precipitation (Environment Canada 2003). The scarcity of snow and rarity of hard frosts allows the vegetation to remain green throughout the winter. Strong moisture deficits turn the ground vegetation brown in mid-summer.

While all of the species addressed in this strategy occur in maritime meadows, some of them also occur in associated ecosystems. These ecosystems include: rocky coastal bluffs, mesic open deciduous or coniferous woodlands, open shrubby areas and vernal pool margins. This strategy deals with all sites in Canada where each of these species occur. Recovery of the butterfly species covered in this strategy may require consideration of actions on a broader suite of habitat types in order to effect recovery and will be guided by the recovery goals and needs of each species.

The term “maritime meadow” is an informal designation and there is no classification of such ecosystems in British Columbia. Maritime meadows are low-elevation (< 30 m), herb-dominated ecosystems largely confined to coastal situations (within 3 km of the shoreline) along southeastern Vancouver Island and a subset of islands in the Straight of Georgia, Haro Strait and the Strait of Juan de Fuca. Summer temperatures are greatly moderated by proximity to the ocean. Coastal fogs bring heavy dew in the late summer and early fall, stimulating germination and breaking shoot dormancy in many perennials even as inland areas remain dry and brown. Coastal fogs and the proximity to shoreline also tend to moderate winter frosts (particularly at night), retard the accumulation of heat and may slow down the development of plants, particularly in the late spring (Fairbarns pers. obs. 2004). Maritime meadows may be largely free of woody vegetation for a variety of reasons, including strong summer moisture deficits (particularly on wind-exposed sites and/or those with thin, coarse-textured soils), salt spray and a long history of First Nations burning. These forces may act alone or in concert, consequently some maritime meadows are subject to forest ingrowth while others remain open despite fire suppression.

Maritime meadows only occupy a small portion of coastal habitats, even where the natural vegetation remains. Cool north- and east-facing slopes and sheltered pockets of deep soils allow establishment of forest species while shallow, outcropping rock provides too little moisture to sustain maritime meadow species. There are no rigorous estimates of their former extent, but maritime meadows likely occupied less than 2,000 ha of heavily-fragmented habitat even in the early 18th century prior to European colonization. Since then, the area of maritime meadow habitats has declined substantially on southeast Vancouver Island. Early settlers drastically altered Garry oak and associated ecosystems by introducing grazing, cultivation and exotic plants (MacDougall et al. 2004) and fire suppression has favoured forest encroachment and ingrowth of woody species on sites that were formerly maintained by First Nations burning (c.f. Fuchs 2001). The future of remaining areas of maritime meadow is also at risk because they occur on high value shoreline property in a densely-populated, fast-growing region. From 1991-2001, the population in the Capital Region increased by 8.6% with the fastest growing areas in the Western Communities (16.6%) and the Gulf Islands (18.1%) (CRD 2002).Growth in the Capital Region is forecast to increase by 28.9% in 2026 from 1996 population levels (CRD 2001). Trends in Garry oak forests and woodlands, which have declined by 95% as a result of European settlement, provide a useful reference point for the decline of maritime meadows (Lea 2002). Maritime meadows have probably declined at least as much, since they are subject to even more intense development pressure due to the habitats’ slope and aspect, which was desirable for agriculture and grazing, and their proximity to the ocean. It appears quite likely that less than 200 ha of maritime meadow remain relatively intact.

Maritime meadow ecosystems with over 5% cover of California oatgrass (Danthonia californica), Roemer’s fescue (Festuca idahoensis ssp. roemeri) and/or native elements of red fescue (Festuca rubra) have been described for the adjacent Puget Trough in Washington State but other maritime meadow ecosystems in the area have not been classified (Chappell 2004b). Many of the maritime meadow communities in Canada fall into the unclassified group, so it would be premature to cross-reference Canadian maritime meadows with Washington State plant communities. Accordingly, it is not possible to assess the global extent or conservation of maritime meadow communities.

While there is no classification of maritime meadows in Canada, certain patterns are worthy of comment. The most drought-prone sites, referred to as dry maritime meadows in this strategy, tend to be well-drained and have quite low vegetation. They tend to support many low-growing species that are out-competed on more productive sites. Mesic maritime meadows warm up more slowly in the spring and dry out more slowly as the summer drought develops. They tend to support more productive vegetation and often have a substantial component of robust invasive grasses. Moist maritime meadows develop where water tends to pond slightly during the winter. They are transitional to vernal seeps and their vegetation tends be dominated by small plants that wither quickly with the onset of summer drought. Excluded from this classification are meadows composed of tall grasses and herbs occurring in areas with brief or non-existent summer moisture deficits. Such communities, which are transitional to coastal marshes, tend to have a quite different vegetation composition from the maritime meadow types described above. Furthermore, the rare species addressed in this recovery strategy are not known from such ecosystems.

As mentioned above, many of the ‘maritime meadow’ plant species addressed in this recovery strategy also occur on closely related ecosystems (refer to Table 3 for key habitat characteristics). Bearded owl-clover tends to occur in moist meadows or along the margins of vernal pools and seeps. Such habitats are described by Miller (in prep.). Coastal Scouler’s catchfly, purple sanicle and seaside birds-foot lotus are most abundant in maritime meadows but also occur in mesic, open Garry oak woodlands (c.f. Douglas and Smith in prep.). Seaside birds-foot lotus also occasionally occurs in mesic, open coniferous forests but these populations probably established in maritime meadows, and the conifer canopy has developed as a result of subsequent forest ingrowth. Prairie lupine formerly occurred in maritime meadows but is recently known only from higher elevation grassland habitat. Such sites are superficially similar to maritime meadows but have a greatly different vegetation composition, which has not yet been formally described. In addition to maritime meadows, Taylor’s checkerspot habitat can also include areas cleared by humans including powerline right of ways. The single remaining population of island marble on San Juan Island in the United States occurs in a mix of disturbed grassland, sand dunes and shorelines.

 

Table 3: Key habitat characteristics of species at risk in maritime meadows
Environmental Attribute Species
Island marble Taylor’s checkerspot Bearded owl-clover Bear’s-foot sanicle Coastal Scouler’s catchfly Golden paintbrush Prairie lupine Purple sanicle Seaside birds-foot lotus
Climate sub-Mediterranean sub-Med sub-Med sub-Med sub-Med sub-Med sub-Med sub-Med sub-Med
Distance from coast (km) 0-3.5 0-5.0 0-3.0 0-0.1 0-2.5 0-3.0 0-10Footnote d 0-2.5 0-0.1
Elevation (m) unknown 1-250 (600)Footnote a.2 1-10 1-20 1-20 (- 225Footnote b) 1-20 (-60Footnote c) 1-400 1-250 1-25
Slope/aspect unknown Nearly level to very strong slopes facing southwest to northwest Nearly level Nearly level to moderate southeast to southwest slopes Nearly level to gentle slopes with various aspects Nearly level Nearly level to moderate slopes with various aspects Nearly level to very strong southeast to southwest slopes Nearly level to moderate southeast to southwest slopes
Meso slope position unknown Crest, upper slope, middle slope, level depression level, middle slope (lower slope, toe) level (upper slope, middle slope) level crest, upper slope, middle slope, level level, upper slope, middle slope level, lower slope
Drainage unknown Rapidly to poorly imperfectly to poorly well to rapidly well to rapidly moderately well to well rapidly to well moderately well to well moderately well to well
Soil moisture -summer- unknown unknown subarid subarid to arid subarid subarid semiarid semiarid to subarid semiarid to subarid
Soil moisture -winter- unknown unknown peraquic humid to subhumid perhumid to subaquic subaquic to perhumid humid humid to perhumid perhumid to subaquic
Soil nutrient regime unknown unknown unknown unknown unknown unknown unknown unknown unknown
Minimum soild depth unknown unknown unknown unknown unknown unknown unknown unknown unknown
Maximum soil depth/Root-restricting layer unknown Variable- no root restricting layer in gravelly Puget Prairies Usually less than 10 cm - no root restricting layer in sites with moderate to severe exposure to wind and/or salt spray Usually less than 50 cm soil - no root restricting layer in sites with moderate to severe exposure to wind and/or salt spray Usually less than 50 cm soil - no root restricting layer in sites with moderate to severe exposure to wind and/or salt spray Usually less than 50 cm soil - no root restricting layer in sites with moderate to severe exposure to wind and/or salt spray Usually less than 50 cm soil - no root restricting layer in sites with moderate to severe exposure to wind and/or salt spray Usually less than 50 cm soil - no root restricting layer in sites with moderate to severe exposure to wind and/or salt spray Usually less than 50 cm soil - no root restricting layer in sites with moderate to severe exposure to wind and/or salt spray
Coarse frag. content unknown unknown unknown unknown unknown unknown unknown unknown unknown
Mineral soil texture unknown unknown unknown unknown unknown unknown unknown unknown unknown
Humus form unknown unknown unknown unknown unknown unknown unknown unknown unknown
Vegetation unknown Rock bluff, dry meadow, mesic meadow, wet meadow, deciduous woodland, dry or mesic openings in coniferous forest Wet meadow, vernal pool margin Dry meadow Dry meadow, mesic meadow, mesic open deciduous woodland Dry meadow, mesic meadow Dry meadow, rock bluff, open shrubland Dry meadow, mesic meadow, mesic open deciduous woodland Dry meadow, mesic meadow, mesic open deciduous or conif. woodland

 


1.4 Key characteristics of the group of species

1.4.1 Ecology of the species

All of the species are at the northern limits of their distribution in Canada and many are disjunct. Species at the edge of their distribution may be genetically and/or morphologically distinct and protecting these peripheral populations may be important for long-term survival of the species. Although Canada has a small percentage of the current global range of each species (except for Golden paintbrush), the habitat in Canada is an important and significant part of the species’ range. Future climatic changes (review in Fuchs 2001) may make preservation of species at the northern limit of their distribution especially important for species recovery.

In most cases, the ecological significance of these species is not known. Both bearded owl-clover and golden paintbrush are root parasites (hemiparasites). The association between these and related hemiparasites and their hosts is a relatively random process and a broad range of species may be parasitized (Atsatt and Strong 1970). There is no evidence that either of these species have a significant effect on populations of their host species or significantly regulate vegetation composition where they occur. None of the species addressed in this recovery strategy are known to be keystone species, ecologically dominant species, or a significant prey item or pest.

All of the species covered in this recovery strategy prefer open habitat. Each of the plant species is relatively shade-intolerant. The larval and nectar foodplants of both butterfly species require open meadows, and the butterflies inhabit these same meadow conditions. This habitat requirement makes all species particularly vulnerable to invasion by exotic shrubs and encroachment by native woody species due to the suppression of prior disturbance regimes that formerly limited woody invasion. Species adapted to regular disturbance regimes may be less able to compete with highly competitive woody and herbaceous species when disturbances are suppressed.

All of the species have mechanisms to address summer drought periods; five of the seven plants are dormant in the summer and the other two plant species can withstand heavy droughts. Both butterfly species diapause (enter a state of halted development) during summer drought.

All of the plant species have relatively limited dispersal mechanisms that limit their ability to disperse to suitable re-establishment habitat. Both sanicle species have hooked prickles on the seed that can attach to passing animals but the animal vectors do not preferentially select habitats suitable for the plants. Both seaside birds-foot lotus and prairie lupine have seedpods that twist explosively when ripe. However, in highly fragmented ecosystems, these mechanisms may not be sufficient for effective dispersal into unoccupied habitat.

Additional species may be added to this strategy over time. Some of these characteristics may not apply to other species at risk found in maritime meadows.


1.4.2 Economic/cultural value

Some maritime meadows contain large numbers of rare species. Some of the species at risk in this recovery strategy are showy and highly recognized as components of Garry oak and associated ecosystems. Protecting and appropriately restoring these rare ecosystems will help preserve biodiversity and prevent the loss of Canada’s natural heritage. GOERT has identified all of these species as components of integrated recovery efforts for Garry oak and associated ecosystems (GOERT 2002).

There are few references to Aboriginal use of any of the species addressed in this recovery strategy (Moerman 1998; Turner pers. comm. 2004). The Miwok people of California and Nevada states used purple sanicle root as a cure-all and an infusion of the leaves as a remedy for snakebite (Moerman 1998). Although other species in some of the same genera as the species in this recovery strategy (Castilleja spp. Lupinus spp., Silene spp.) have been used for food, medicinal or ceremonial use, with the exception of purple sanicle there are no records of First Nations’ use of the species in this recovery strategy.

None of the species in this recovery strategy are used commercially.


1.5 Rationale for taking a multi-species approach to recovery

To date, multi-species recovery strategies have been uncommon for species at risk in Canada. However, the federal Species at Risk Act permits ecosystem-level recovery planning and the Recovery of Nationally Endangered Wildlife (RENEW) recognizes the importance of a multi-species approach in dealing with multiple species at risk in a limited geographic area. The Garry Oak Ecosystems Recovery Team has used an ecosystem-level approach in the development of the Recovery Strategy for Garry Oak and Associated Ecosystems and their Associated Species at Risk in Canada: 2001-2006 (GOERT 2002).

The complex ecology of British Columbia’s Garry oak and associated ecosystems, and the large number of species at risk (both nationally and provincially-listed species) in maritime meadow ecosystems, are key factors in deciding upon a multi-species approach to recovery. A multi-species approach makes efficient use of limited recovery funds, as well as ecological and human resources. In addition, a multi-species approach is the most efficient one for addressing broad-scale recovery issues including communication planning, reintroduction possibilities, shared stewardship actions, education programs, landscape linkages, etc. (GOERT 2002).

All of the species included in this recovery strategy have a number of features that allow a multi-species approach to be effective. Most occurrences of these species are in highly specialized maritime meadows and many locations support more than one of the species covered in this recovery strategy. Species found in similar habitats also have similar adaptations to habitat conditions that influence potential management options.

A multi-species approach is the most effective one for addressing any conflicting needs between species and for developing appropriate protection and management strategies. A multi-species approach can address both species-specific threats and threats to habitat at the ecosystem level. A focus on habitat will accommodate range shifts and population expansions that cannot be included in a single species approach. Large-scale threats such as climate change and invasive species are best addressed at a broad scale. In the subsequent more detailed recovery action planning stage, specific needs of individual species covered by this recovery strategy can also be addressed and critical habitat proposed that will help ensure survival and effect recovery of a species at risk.

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