Multi-species at risk in maritime meadows (garry oak ecosystems) recovery strategy: chapter 4

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3. Species descriptions

• 3.1 Island marble Euchloe ausonides insulanus
  • 3.1.1 The species
  • 3.1.2 Distribution
  • 3.1.3 Population and distribution trend
  • 3.1.4 Biotic and abiotic features of habitat
  • 3.1.5 Spatial requirements
  • 3.1.6 Annual cycle
  • 3.1.7 Ecological niche
  • 3.1.8 Biologically limiting factors
• 3.2 Taylor’s checkerspot Euphydryas editha taylori
  • 3.2.1 The species
  • 3.2.2 Distribution
  • 3.2.3 Population and distribution trend
  • 3.2.4 Biotic and abiotic features of habitat
  • 3.2.5 Spatial requirements
  • 3.2.6 Annual cycle
  • 3.2.7 Ecological niche
  • 3.2.8 Biologically limiting factors
• 3.3 Bearded owl-clover Triphysaria versicolor ssp. Versicolor
  • 3.3.1 The species
  • 3.3.2 Distribution
  • 3.3.3 Population and distribution trend
  • 3.3.4 Biotic and abiotic features of habitat
  • 3.3.5 Annual cycle
• 3.4 Bear’s-foot sanicle Sanicula arctopoides
  • 3.4.1 The species
  • 3.4.2 Distribution
  • 3.4.3 Population and distribution trend
  • 3.4.4 Biotic and abiotic features of habitat
  • 3.4.5 Annual cycle
• 3.5 Coastal scouler’s catchfly Silene scouleri ssp. Grandis
  • 3.5.1 The species
  • 3.5.2 Distribution
  • 3.5.3 Population and distribution trend
  • 3.5.4 Biotic and abiotic features of habitat
  • 3.5.5 Annual cycle
  • 3.5.6 Biologically limiting factors
• 3.6 Golden paintbrush Castilleja levisecta
  • 3.6.1 The species
  • 3.6.2 Distribution
  • 3.6.3 Population and distribution trend
  • 3.6.4 Biotic and abiotic features of habitat
  • 3.6.5 Annual cycle
  • 3.6.6 Biologically limiting factors
• 3.7 Prairie lupine Lupinus lepidus var. Lepidus
  • 3.7.1 The species
  • 3.7.2 Distribution
  • 3.7.3 Population and distribution trend
  • 3.7.4 Biotic and abiotic features of habitat
  • 3.7.5 Annual cycle
  • 3.7.6 Biologically limiting factors
• 3.8 Sanicle bipinnatifide Sanicula bipinnatifida
  • 3.8.1 The species
  • 3.8.2 Distribution
  • 3.8.3 Population and distribution trend
  • 3.8.4 Biotic and abiotic features of habitat
  • 3.8.5 Annual cycle
  • 3.8.6 Biologically limiting factors
• 3.9 Seaside birds-foot lotus Lotus formosissimus
  • 3.9.1 The species
  • 3.9.2 Distribution
  • 3.9.3 Population and distribution trend
  • 3.9.4 Biotic and abiotic features of habitat
  • 3.9.5 Annual cycle
  • 3.9.6 Biologically limiting factors

3.1 Island marble Euchloe ausonides insulanus

3.1.1 The species

Euchloe ausonides subspecies insulanus is a well-delineated taxon as described in the Committee on the Status of Endangered Wildlife in Canada (COSEWIC) Status report (Shepard 2000b). The species was recognized as a separate subspecies as described in Guppy and Shepard (2001).

The island marble is a white and greyish black butterfly with a marbled texture to the underside of the hindwings and black markings at the tips of the forewings. The veins on the hindwings are emphasized as yellowish lines, giving the species a marbled appearance. The sexes are similar but the females have darker yellowish marbling on the hindwings, and a yellow ground colour, compared to the white of the males. The body is covered with whitish-yellow hairs giving it a fuzzy appearance.

Figure 1: Approximate global and Canadian distribution of island marble

Extant populations shown as stars, extirpated populations as triangles.

3.1.2 Distribution

The subspecies Euchloe ausonides insulanus is isolated from the rest of the species’ range. The species as a whole is found from Alaska south to California and Colorado and east to Ontario and Minnesota.

The current global range of the subspecies, insulanus consists of one known population in Washington State (S1), identified in 1998 at San Juan Island Historical Park, American Camp, San Juan Island, Washington (Figure 1) (J. Fleckenstein per. comm. 2002). Other than this single population, the subspecies insulanus has not been documented in the United States. The subspecies has been extirpated from British Columbia (Hinchliff 1994, 1996; Layberry et al. 1998).

3.1.3 Population and distribution trend

The island marble is known from 14 historical records in Canada suggesting the existence of five naturally fragmented populations distributed among the Greater Victoria area (Langford, Beacon Hill Park and James Bay), and Nanaimo (Wellington) on Vancouver Island and Gabriola Island (Figure 1). The earliest record, from the 1860s, was a specimen labeled simply ‘Vancouver;’ this was most likely a reference to Vancouver Island. The species is presumed extirpated by about 1910, with the last record in Canada being in 1908 on Gabriola Island. Recent survey efforts have not located any new populations of this species in Canada.

Extirpation of the island marble in Garry oak ecosystems in Canada occurred prior to substantial habitat loss of these ecosystems. It is suspected that grazing by sheep and/or cattle prior to, or during World War I eliminated the larval foodplant (suspected to be hairy rockcress [Arabis hirsuta]) and acted as the primary cause leading to extirpation of this species from British Columbia (Shepard 2000b). The overall reasons for extirpation are unknown.

There is no published estimate of global abundance for the population on San Juan Island. At least 20 individuals were observed in 2002, (Fleckenstein pers.comm. 2002; Miskelly pers. comm. 2004), and at least 100 in 2003 (Pyle pers. comm. 2003), but no population estimate was completed. There is no indication of the former total number of individuals in Canada.

3.1.4 Biotic and abiotic features of habitat

Since the island marble has not been recorded in Canada since 1908, habitat requirements are based on information from the San Juan Island population in the United States and current descriptions of sites with historic records.

The San Juan Island population lives in a large (> 100 ha) open area that contains three distinct habitats: mesic, disturbed grassland; sand dunes; and shorelines. The area primarily faces west and is devoid of large trees. The areas used by the butterflies are not steep: slopes range from flat to up to 50% (Miskelly pers. obs. 2004). Introduced mustards (Brassicaceae) are patchy but abundant in the grassland and sand dunes, while native foodplants are abundant along the shorelines. Native and introduced weedy mustards (Brassicaceae) usually reach their highest densities in moderately disturbed areas. The mustard plants in the grasslands grow in areas disturbed by burrowing mammals (Fleckenstein pers. comm. 2002; Miskelly pers. comm. 2004; Pyle pers. comm. 2003). There are no similar habitats of this scale in Canada.

The extant population on San Juan Island, Washington, oviposits on the introduced European weeds field mustard (Brassica campestris) and tumble mustard (Sisymbria altissimum), and the native tall pepper-grass (Lepidium virginicum), family Brassicaceae (Fleckenstein pers. comm. 2002; Miskelly pers. comm. 2004; Pyle pers. comm. 2003). This is consistent with documented use of weedy introduced Brassicaceae by larvae of other subspecies of Euchloe ausonides (Opler 1975). Field mustard grows in more mesic habitat than native rockcress (Arabis) species, and is therefore less susceptible to early dessication.

In Canada, it is likely that the island marble was associated with open grassland successional stages of Garry oak and associated ecosystems. Larval foodplants in British Columbia were likely rockcress (Arabis spp.), perhaps A. hirsuta (Shepard 2000a; 2000b), as well as tall pepper-grass (Lepidium virginicum). Rockcress (Arabis spp.) is the major foodplant for subspecies mayi in the southern interior of BC. However there is no historical record of the larval foodplants or the habitats used.

3.1.5 Spatial requirements

The amount of habitat needed to sustain a viable population is unknown. It is likely that a moderately large habitat patch or close proximity to other patches is required for long term survival. A patch of 50 to 100 hectares of high quality habitat may be required, based on an estimate of a 100 ha area inhabited by the extant population on San Juan Island although further research is required to determine minimum habitat sizes. There are very few habitat patches of this size that remain in British Columbia.

3.1.6 Annual cycle

Eggs hatch from late May to late June and larvae feed until pupation, which occurs between late-June and late-July.

High mortality results if the larval food plants desiccate prior to pupation. The amount of spring and early summer rain affects the date of food plant senescence, and hence larval success in reaching pupation.

3.1.7 Ecological niche

There has been no research on the ecological role of this butterfly. The adults may be minor pollinators of flowers. The larvae are minor herbivores of Brassicaceae family and feed on flowers and fruits. Adults, larvae and pupae may serve as prey for insectivorous birds, small mammals, and predatory insects (Family Braconidae). Eggs, larvae and pupae are likely to also function as hosts for insect parasitoids (van Nouhys and Hanski, 2004).

3.1.8 Biologically limiting factors

There is minimal knowledge of the biologically limiting factors for the island marble. Flight and dispersal capabilities have not been studied. Observations on the behaviour of subspecies mayi, suggest that individual adults may move significant distances during their lifespan. In California, near the ocean, adults of E. ausonides have been documented moving up to one kilometre (Scott 1975a; 1975b).

The larvae of island marbles are actively feeding during late May and June, the later part of the period in which Btk is scheduled for application in the historic range of the species in British Columbia (Nealis pers. comm. 2003).

3.2 Taylor’s checkerspot Euphydryas editha taylori

3.2.1 The species

Taylor’s checkerspot is a medium-size butterfly. The upper wing surfaces have distinct alternate black and orange bands. Wing undersides show a pattern of orange, white, red, pale cream and black-checkered bands outlined with black. Checkered bands are parallel to the black thorax and abdomen. The front wings have rounded tips. Males are slightly smaller than females.

Caterpillars are black with orange bands. Eggs are pale yellow and transparent. Euphydryas editha taylori is a well-delineated taxon as described in the COSEWIC Status report (Shepard 2000c).

3.2.2 Distribution

The current global range consists of fifteen known populations in Clallum County and the south Puget Sound (Washington) (S1), and the Willamette Valley (Oregon) (S1) (Figure 2).

In Canada, Taylor’s checkerspot is known historically from 22 naturally fragmented populations: fifteen sites in the greater Victoria area, three sites from Mill Bay to Duncan, three sites on Hornby Island and one near Courtenay (Figure 2). Records date from 1887 to 1995. The species is currently listed as Endangered (2000), although recent surveys in 2001 and 2003 of the last known sites confirmed the species is likely extirpated from Canada (Miskelly 2003). However, in 2005, 15 individuals were found on Denman Island, near Courtenay on Vancouver Island (Jennifer Heron, pers. comm., 2005).

Figure 2: Global and Canadian distribution of Taylor’s checkerspot

Extirpated populations shown as triangles.

3.2.3 Population and distribution trend

Many of the populations in the Victoria area persisted until the 1950s except the Beacon Hill Park population, which was likely extirpated by the early 1930s. In 1989, only one population remained, which was in a powerline right-of-way 3 km southwest of Mill Bay (Shepard 2000c), which was also extirpated by 1995 (Shepard 2000a). In 1995, several populations were found on Hornby Island, were known to be extant in 1996 (Shepard 1995; Shepard 2000b; 2000c), but were thought to be extirpated by 2001 (Guppy and Fischer 2001).

Although trends are not documented specifically for Taylor’s checkerspot habitat, Garry oak and associated ecosystems have declined substantially. Fire suppression and conifer encroachment into areas of water seepage and deeper soil, coupled with drought, may have extirpated the Helliwell Park population on Hornby Island.

In Washington State, population sizes are unknown. The two populations in Oregon state are estimated at 1000 (Vaughan and Black 2002b) and 500 (Black pers. comm. 2004). Historic Canadian populations numbered 1100 at Hornby Island (1996) and 1000 at Mill Bay (1989) (Shepard 2000c) but there is no indication of the former total number of individuals in Canada.

3.2.4 Biotic and abiotic features of habitat

Habitat descriptions for the Taylor’s checkerspot are based on observations of the last known occupied locations cccc and current descriptions of sites with historic records. There are no completed habitat studies for this butterfly in Canada, although research is underway at the University of Victoria (Eastman et al. 2002).

Taylor’s checkerspot requires non-forested habitats (Shepard 2000b; 2000c). Native ecosystem habitats are not necessarily required; areas cleared by human activities, such as powerline rights-of-way, can be suitable habitat (Vaughan and Black 2002b; Shepard 2000b; 2000c). Recent surveys in Washington have found thriving populations in new locations uncharacteristic of historic populations, including a site at 600m elevation in habitat that was formerly logged and burned with sheer cliffs interspersed with the native species oceanspray (Holodiscus discolor), ceanothus (Ceanothus sp.) and currants (Ribes spp.) (Miskelly pers. comm. 2004).

Foodplants of extant populations in the United States are ribwort plantain (Plantago lanceolata), harsh paintbrush (Castilleja hispida), large-flowered blue-eyed Mary (Collinsia grandiflora), sea blush (Plectritis congesta) and one record of dwarf owl-clover (Triphysaria pusilla) (Grosboll pers.comm. 2004, Potter pers. comm. 2003;2005). Taylor’s checkerspot larvae may also use sea plantian (Plantago maritima), golden paintbrush (Castilleja levisecta), and possibly other owl-clover species (Murphy et al. 1983; Pelham, pers. comm. 2003).

It is unknown whether any populations in British Columbia used anything other than ribwort plantain (Plantago lanceolata) as a primary or secondary foodplant (Shepard 2000b; 2000c; Danby 1890). It is speculated that Taylor’s checkerspot populations in British Columbia could have used the same, additional foodplants as those used by butterflies in Washington.

Nectar is not required for reproduction, but egg production in subspecies E. editha bayensis is dependent on available nectar sources, with up to double the number of eggs laid when nectar was abundant (Murphy et al. 1983). Important nectar sources for extant populations of Taylor’s checkerspot in the United States include common camas (Camassia quamash), strawberries (Fragaria spp.), spring gold (Lomatium utriculatum), and sea blush (Plectritis congesta) (Potter pers. comm. 2003; Grosboll pers. comm. 2003; Ross pers. comm. 2003). Nectar plants for former British Columbia populations are not known.

This species is particularly vulnerable to invasion by exotic shrubs, which decreases the availability and amount of foodplants. Scotch broom (Cytisus scoparius) invasion of human-cleared habitat resulted in the extirpation of the population near Mill Bay, BC (Shepard 2000b; 2000c). Invasion was implicated in the extirpation of at least one Washington population, and may threaten one remaining population in Oregon (Vaughan and Black 2002b). The Bright Angel Provincial Park population, south of Duncan, British Columbia, was extirpated by subdivision development adjacent to the park, combined with increased native shrub growth within the park (Guppy, pers. comm. 2003).

3.2.5 Spatial requirements

In order to ensure long-term survival of a population, the required patch size is estimated to be 5 to 20 hectares of high quality habitat (abundant ribwort plantain [Plantago lanceolata] or harsh paintbrush [Castilleja hispida] and nectar sources). These figures are based on estimates of the areas occupied by historic populations (Guppy pers. comm. 2003). Several extant populations occupy areas of less than one hectare (Miskelly pers. obs. 2004).

3.2.6 Annual cycle

The related subspecies, Euphydryas editha bayensis, typically lays an initial mass of 130-180 eggs, with each female laying several batches of eggs of successively smaller numbers (Murphy et al. 1983). This is consistent with the size of clusters of first instar larvae observed at the Taylor’s checkerspot site southwest of Mill Bay (Guppy pers. comm. 2003). The larvae hatch from eggs in May or early June and feed until they are in the late third instar and enter diapause. Techniques of captive oviposition of checkerspots, with or without captive mating, are well known and easily implemented (eg. Murphy et al. 1983). In 1988/89, Guppy (pers. comm. 2003) successfully reared Taylor’s checkerspot larvae, collected as second instar from near Mill Bay, BC. In 2004, Taylor’s checkerspot rearing experiments were conducted using 20-40 larvae collected in Thurston and Clallum County, Oregon. A more rigorous rearing program for Taylor’s checkerspot is scheduled to begin in 2005 (Potter pers. comm. 2005). There may be significant phenological differences between populations in Canada and the United States that suggest some degree of genetic divergence (Guppy pers. comm. to Miskelly 2004).

3.2.7 Ecological niche

There has been no research on the ecological role of this butterfly. The adults, when at high densities, may be significant pollinators of native spring flowers. The larvae are major herbivores of ribwort plantain when at high densities, and can completely strip off all leaves on plants in some patches (Guppy pers. comm. 2003). There is no evidence that this herbivory adversely affects the viability of plantain populations. Adults, larvae and pupae may serve as prey for insectivorous birds, small mammals, and predatory insects. However they contain iridoid glycosides (sequestered from their larval foodplants), and hence are not palatable to most predators. Eggs, larvae and pupae are likely to also function as hosts for insect parasitoids (van Nouhys and Hanski 2004).

3.2.8 Biologically limiting factors

Dispersal capabilities of Taylor’s checkerspot have not been studied. Adults of subspecies E. editha bayensis and E. editha wrighti only move 200 to 300 feet under favourable environmental conditions even within patches of suitable habitat, but may disperse more widely under stress of drought or high densities, and have difficulty establishing new populations even when transplanted (Ehrlich 1961; Ehrlich et al. 1980; Harrison 1989; Murphy and White 1984). E. editha taylori appears to be less limited in dispersal abilities, and has been observed crossing forested areas and other barriers (Potter pers.comm. 2003; Vaughn pers. comm. 2003; Black pers. comm. 2004). Metapopulations of subspecies bayensis rely on a large, stable central population as a source to establish and stabilize peripheral populations (Harrison 1989). If new populations are re-established in Canada, distance between patches of suitable habitat may have a strong influence on dispersal potential. In some instances, populations of subspecies bayensis are very close to another and share very few individuals and did not rescue one another from extirpation (Hellmann et al. 2003, McLaughlin et al. 2002).

Larval starvation results when the foodplants, especially plantain, desiccate due to summer drought prior to the larvae entering diapause (Vaughan and Black 2002b). This is believed to be the main cause of mortality in this species. The effects of weather on larval success in reaching diapause, and on survival through diapause, has been demonstrated to be a key variable in determining adult population size and population persistence in the Californian subspecies bayensis (McLaughlin et al. 2002). Viable populations of other subspecies in California are around 1000 individuals (Ehrlich 1961; Hellmann et al. 2003) with smaller populations having greater susceptibility to extirpation by droughts or other stochastic events. However, even populations that numbered around 1000 individuals have become extirpated (Hellman pers. comm. 2005). Climate change is expected to increase rates of extinction for Taylor’s checkerspot (McLaughlin et al. 2002) by limiting the variability of foodplants phenology.

Taylor’s checkerspot larvae are actively feeding during the early spring when Btk is normally applied to control forest pests (Wagner and Miller 1995; Nealis pers. comm. 2003).

3.3 Bearded owl-clover Triphysaria versicolor ssp. versicolor

3.3.1 The species

Triphysaria versicolor Fisch. & C. Meyer ssp. versicolor is a well-delineated taxon as described in the status report (Penny et al. 1996). T. versicolor ssp. faucibarbatus, the only other taxon within the species, is restricted to California (Chuang and Heckard 1993). Bearded owl-clover is a small (10-50 cm) annual herbaceous plant with tiny hairs on the leaves and stems. The leaves are pinnately divided onto linear segments. The inflorescence, a terminal spike, has white or pink flowers and leaf-like bracts. The club-shaped corollas distinguish bearded owl-clover from narrow-leaved owl-clover (Castilleja attenuatus). It can be distinguished from dwarf owl-clover (T. pusilla), which is a smaller plant with more finely dissected leaf segments (Douglas et al. 2000; Penny et al. 2000). Bearded owl-clover is a root-parasite (hemiparasite) that appears to parasitize a broad range of host species.

3.3.2 Distribution

Bearded owl-clover ranges from southern Vancouver Island, south along the Pacific coast to southern California (Figure 3). The species is absent from Washington State and northern Oregon; the Canadian populations are disjunct, by about 500 km², from the next nearest populations in Lane County (Oregon). In the United States, bearded owl-clover is ranked SNR in California and Oregon, the only two states where it occurs (NatureServe 2004).

In Canada, the historical extent of occurrence covered approximately 95 km² and the current extent of occurrence is under 15 km². The COSEWIC status report estimates the area of occupancy to be 379 m² although since this report two newly documented populations (combined area under 200 m²) place the total area of occupancy in Canada under 600 m².

Figure 3: Global and Canadian distribution of bearded owl-clover

Global distribution on left; Canadian distribution on right with open stars showing extirpated populations and solid stars showing locations of one or more extant populations.

3.3.3 Population and distribution trend

There are seven extant populations and one that has been extirpated. This has been confirmed using the description of populations from the BC Conservation Data Centre criterion for recognizing distinct populations (those separated by less than 1000 m as subpopulations) in addition to subsequent surveys.

The COSEWIC status report describes eight extant ‘populations’ and two or three other populations (the record from Mount Finlayson may have been based on a misidentification) which have not been reported for more than 80 years (Penny et al. 1996). The COSEWIC status report estimates a total population size of between 4000 and 5000 plants (Penny et al. 1996). Subsequent surveys (Table 11) of some populations indicated that their numbers may be higher, at least in favourable years.

3.3.4 Biotic and abiotic features of habitat

Bearded owl-clover grows in maritime meadows and seepages. It is largely restricted to low sites <10 m above sea level and within 30 m of the shoreline. It occurs in rocky areas and moderately shallow soils and its habitat is often maintained open by a combination of salt spray, wind, summer drought and winter seepage, which combine to prevent trees, shrubs and more robust herbs from becoming established. It occurs in vegetation dominated by grasses and forbs. The sites have not been ploughed in the past but often contain large amounts of invasive alien pasture grasses including orchard-grass (Dactylis glomerata), barren brome (Bromus sterilis), soft brome (B. hordeaceus), sweet vernalgrass (Anthoxanthum odoratum), hedgehog dogtail (Cynosurus echinatus) and common velvet-grass (Holcus lanatus). The meadow soils are fresh or wet throughout the winter months but dry to the permanent wilting point by mid-summer.

3.3.5 Annual cycle

Bearded owl-clover is an annual plant. Unpublished notes (M. Fairbarns 2003 and 2004) have documented the annual cycle.

Unpublished notes (M. Fairbarns 2003 and 2004) from Harling Point, Victoria Golf Club, Glencoe Cove and Strongtide Island reveal the following cycle. Germination begins in January. At least some seedlings, bearing nothing but cotyledons, are found as late as mid-March. True leaves are evident on rapidly growing plants by as early as February. Most plants are dead by late June. Flowering begins in April and may continue until late May. Fruit development begins in late April and seed dispersal in some plants continues into July.

3.4 Bear’s-foot sanicle Sanicula arctopoides

3.4.1 The species

Sanicula arctopoides Hooker and Arn. Is a well-delineated taxon as described in the status report (Donovan and Douglas 2000). Kartesz (1994) does not recognize any intraspecific taxa within this species.

Bear’s foot sanicle is a tap rooted perennial with prostrate or ascending branches (5-30 cm long). Basal leaves form a rosette and are irregularly toothed, somewhat succulent and often yellowish. Stem leaves are reduced. The inflorescence is several to many compact umbels with bright yellow corollas surrounded by a distinct involucel. The seeds are egg-shaped schizocarps with hooked prickles. Bear’s foot sanicle is distinguished from other sanicle species by its prostrate growth habit and conspicuous involucels (Douglas et al. 1998a; Donovan and Douglas 2001).

3.4.2 Distribution

Bear’s-foot sanicle ranges from southern Vancouver Island, south along the Pacific coast to central California (Figure 4). The Canadian populations are disjunct, by about 150 km, from the next nearest populations on the west coast of central Washington State. The species is ranked S1 in Washington and SNR in California and Oregon (Natureserve 2004).

In Canada, bear’s-foot sanicle is restricted to a small area in and near Victoria, British Columbia. The historical and current range encompassed a narrow coastal fringe about 100 km long but only about 50 m wide, hence the extent of occurrence never exceeded about 5 km². The COSEWIC status report estimates the area of occupancy to be 3614 m². The combined area of populations subsequently documented at Rocky Point and on Discovery and Mary Tod Islands covers less than 200 m². The extirpated populations at Chain Island, Cadboro Bay, Clover Point, Beacon Hill and Foul Bay are unlikely to have covered more than 1000 m². From this data, the current area of occupancy in Canada is estimated at 3814 m², down from a historic value of as much as 4814 m².

Figure 4: Global and Canadian distribution of bear’s-foot sanicle

Global distribution on left; Canadian distribution on right with extant populations shown as stars, extirpated populations as triangles.

3.4.3 Population and distribution trend

The COSEWIC status report describes five extant populations, one population with an ‘unknown’ status, and four extirpated populations (Donovan and Douglas 2000). Four new populations have been documented since this report and another extirpated population at Cattle Point has been confirmed. There are now nine known, extant populations of bear’s-foot sanicle and it appears that 3-4 populations have become extirpated (Table 12).

There is no indication of the past total number of plants in Canada. The COSEWIC status report estimates a total population size of 7364 plants, although this includes both flowering and non-flowering individuals. The newly documented occurrences add slightly to the total estimated population. Unfortunately, there is no accurate estimate of the reproductive population, the criterion that COSEWIC uses to rank species.

3.4.4 Biotic and abiotic features of habitat

The habitat of bear’s-foot sanicle consists of dry maritime meadows. The following information on ecosystem structure is from the COSEWIC status report supplemented by recent vegetation sampling (Fairbarns pers. obs. 2004). These meadows are less than 10 m above sea level. Their soils are over 15 cm deep and remain moist throughout the winter months but dry to the permanent wilting point by late spring. The sites have never been ploughed or hayed, but some have been lightly grazed by livestock and most probably burned in the past.

Trees are not present due to wind exposure, salt spray and the extreme droughty nature of the shallow soils. The same environmental stresses usually preclude the presence of shrubs, although small amounts of salal (Gaultheria shallon), Nootka rose (Rosa nutkana) and/or the alien Scotch broom (Cytisus scoparius) are occasionally present.

The herb layer is typically dominated by a mix of native and introduced species. The leading native species are forbs (Puget Sound gumweed [Grindelia integrifolia], thrift [Armeria maritima], field chickweed [Cerastium arvense], small-flowered birds-foot trefoil [Lotus micranthus], Spanish clover [Lotus unifoliolatus], white triteleia [Triteleia hyacinthina], slender plantain [Plantago elongata], dwarf owl-clover [Triphysaria pusilla]), although a small component of native graminoids (California oatgrass [Danthonia californica], many-flowered wood-rush [Luzula multiflora], beach bluegrass [Poa confinis]) may be present.

Introduced grasses (rip-gut brome [Bromus rigidus], soft brome [B. hordeaceus], hedgehog dogtail [Cynosurus echinatus], red fescue [Festuca rubra], early hairgrass [Aira praecox], fescues [Vulpia spp.]) and forbs (hairy cat’s ear [Hypochaeris radicata], ribwort plantain [Plantago lanceolata], small-flowered catchfly [Silene gallica], small hop-clover [Trifolium dubium]) are often present, and any of these may dominate at a given site.

Mosses and lichens are usually sparse in extent, but Dicranum scoparium, Racomitrium canescens, Homalothecium sp. and Cladonia portentosa are often present.

3.4.5 Annual cycle

The COSEWIC status report provides little information on the annual cycle of bear’s-foot sanicle although subsequent research has added pertinent information (Fairbarns in. prep. c.).

Germination occurs in January or February depending on weather events and site characteristics. Seedling mortality is low initially, with most juveniles developing 1-3 true leaves before the onset of the summer drought. Most populations are so dense that the survival of individual plants over the summer dormant season can’t be determined. The dense nature of populations of this monocarpic perennial species suggests that survivorship through the first drought season is relatively high.

Established plants re-sprout after the summer/fall drought. Fresh rosettes appear as early as September if there are late summer rains which moisten the soil. In typical years shoot dormancy does not break until October or early November. Plants grow slowly through the winter and begin to die back by May. Most shoots are dead by June although a few large non-reproductive rosettes may not die back completely until early July.

Flower buds are usually evident by mid-February and flowering peaks in March or early April. Green fruit are evident by mid-May and fruit ripen in June. Fruit are shed slowly and many plants retain up to 20% of their fruit until October. Most of the barbed fruit are dispersed when animals brush against the plants but some fruit are dispersed when the dead shoots they are attached to snap off and tumble away.

3.5 Coastal Scouler’s catchfly Silene scouleri ssp. grandis

3.5.1 The species

Silene scouleri and its close relatives form a taxonomically difficult complex (Morton pers. comm. 2002). Most authors recognize S. scouleri Hooker ssp. grandis Hitchcock and Maguire at the subspecies or variety level.

Coastal Scouler’s catchfly is an erect (15-80 cm), taprooted perennial from a branched caudex. Basal leaves form rosettes and stem leaves are opposite, reducing in size up the stem. Leaves are hairy, unstalked and have no teeth or stipules. The flowers are greenish-white to purple and form a spike. The united sepals form a prominently nerved tube. Pimply seeds are contained in dry capsules (Douglas et al. 1998b; Fairbarns and Wilkinson 2003).

3.5.2 Distribution

Coastal Scouler’s catchfly occurs in a small area of southeastern Vancouver Island and nearby areas of Washington (Figure 5). The northern populations are disjunct by about 550 km from the main range of the species, along coastal areas from southern Oregon to the San Francisco Basin.

In Canada, coastal Scouler’s catchfly is restricted to two small islands near Victoria, BC. The historical extent of occurrence encompassed approximately 600 km² although the current extent of occurrence is about 0.6 km². The COSEWIC status report (2002) estimates the area of occupancy to be 1.58 ha yet subsequent surveys revise this figure to 2.0 ha (Fairbarns pers. obs. 2004).

Coastal Scouler’s catchfly has not been ranked globally or in the states of California, Oregon and Washington (NatureServe 2004). The species is absent from central and southern Washington State as well as northern and central Oregon. This raises the possibility that the Canadian populations (together with nearby populations in north-central Washington State) may have become genetically distinct from populations in the main range of the species.

3.5.3 Population and distribution trend

The COSEWIC status report describes two extant populations and at least six further populations that have become extirpated although there may have been up to four further populations. (Table 13).

The COSEWIC status report estimated a total population size of between 278 and 328 mature (flowering) plants. Surveys in 2004 revealed the existence of a further 18 flowering plants on Trial Island. The total past Canadian population is unlikely to have exceeded 5000 individuals.

Figure 5: Global and Canadian distribution of coastal scouler’s catchfly

Global distribution on left; Canadian distribution on right; triangles show extirpated populations and stars show extant populations.

3.5.4 Biotic and abiotic features of habitat

The habitat of coastal Scouler’s catchfly consists of mesic maritime meadows. The COSEWIC status report provides information on ecosystem structure supplemented by recent vegetation sampling (Fairbarns pers. obs. 2004). Suitable meadows are less than 30 m above sea level although the Mount Tzuhalem population occurred at about 250 m and the elevation of the extirpated Mount Douglas population was also higher. The meadow soils are moist throughout the winter months but dry almost to the permanent wilting point by late summer. Most plants are rooted in soil over 15 cm deep, and those plants that do occur on shallow soils wilt before flowering (except in the very wet summers). The sites have never been ploughed or hayed, but some have been lightly grazed by livestock and most probably burned in the past.

Trees are generally absent due to the wind exposure, salt spray and the droughty nature of the shallow soils. There was a very open canopy of Garry oak (Quercus garryana) at the Mount Tzuhalem site. Native shrubs are often sparse or absent although snowberry (Symphoricarpos albus) and Nootka rose (Rosa nutkana) are sometimes present. These two shrub species often form dense thickets at the edge of populations of coastal Scouler’s catchfly and may advance into the populations in moist years, presenting a threat to the species. Wildfires and First Nations burning may have formerly constrained the advance of these low shrub thickets. Alien, invasive shrubs such as Scotch broom (Cytisus scoparius) and gorse (Ulex europaeus) (and to a lesser extent spurge laurel [Daphne laureola], English ivy [Hedera helix] and Himalayan blackberry [Rubus discolor]) are sometimes abundant and will probably invade all locations of coastal Scouler’s catchfly in the absence of continuing control activities.

A mix of native and introduced species typically dominates the herb layer. The leading native species are forbs (strawberry [Fragaria spp.], bracken fern [Pteridium aquilinum], white-top aster [Sericocarpus rigidus], field chickweed [Cerastium arvense], yarrow [Achillaea millefolium], woolly eriophyllum [Eriophyllum lanatum], Puget Sound gumweed [Grindelia integrifolia], barestem desert-parsely [Lomatium nudicaule]), although native grasses (tufted hairgrass [Deschampsia cespitosa], blue wildrye [Elymus glaucus], red fescue [Festuca rubra]) are also present at some locations. Common camas (Camassia quamash) and broad leaved shootingstar [Dodecatheon hendersonii] are abundant in the spring at some locations. Introduced grasses (common velvetgrass [Holcus lanatus], Kentucky bluegrass [Poa pratensis], sweet vernalgrass [Anthoxanthum odoratum], hedgehog dogtail [Cynosurus echinatus]) are usually more abundant than introduced forbs (hairy cat’s ear [Hypochaeris radicata], sheep sorrel [Rumex acetosella], ribwort plantain [Plantago lanceolata], common vetch [Vicia sativa]).

3.5.5 Annual cycle

Information in the COSEWIC status report has been updated by subsequent field studies of plants on Trial island (Fairbarns in. prep. e.).

Established plants send out new shoots in July, August and September after the summer drought is broken. The shoots grow slowly during the winter but in May and June reproductive shoots elongate. Some of the tall shoots wilt and die back during the summer drought in July and August. Less stressed tall shoots develop flower buds, which begin to swell in late June and flower in July or early August. Most plants have ceased flowering by late August although plants on moister microsites may continue to develop flowers into September or October. Late forming flowers fail to produce viable fruit. Mature fruit on early flowers begin to dehisce in late August. Seeds gradually sift out of the dehisced capsules as shoots are shaken in the wind and late-maturing capsules may continue to shed seed well into November. Most dead shoots remain upright long after all seeds have been dispersed.

3.5.6 Biologically limiting factors

Germination occurs in March or April, when dense clusters of seedlings are sometimes found near the base of plants that bore seed in the previous year. Seedling mortality is high, with many seedlings wilting during brief dry periods when the upper soil layers dry out. Survivors grow slowly and do not flower in their first year. It is not clear how long plants take to flower in the wild but even in well-watered gardens most plants do not flower until they are three years old. Many shoots fail to elongate in any given year, and those that do often succumb to drought-induced wilt before flowers are produced. Reproductive shoots that survive until the summer drought is broken often fail to produce viable seed before cool autumn weather arrives and development ceases. Immature capsules rot during the winter. The potential for recovery of coastal Scouler’s catchfly is limited by the failure of some populations to produce viable seed before growth ends with cool fall weather.

3.6 Golden paintbrush Castilleja levisecta

3.6.1 The species

Castilleja levisecta Hooker is a well-delineated taxon as described in the status report (Douglas and Ryan 1995).

Golden paintbrush is a multi-stemmed, erect (10-50 cm) perennial herb from a woody stem-base. The glandular, hairy leaves are alternate and range from entire to 3-lobed further up the stem. The inflorescence is a terminal spike with golden-yellow bracts that conceal the inconspicuous flowers. The dry capsules have many tiny seeds (Douglas et al. 2000; Ryan and Douglas 1995).

3.6.2 Distribution

Golden paintbrush ranges from in and near Victoria on southern Vancouver Island and offshore islands to the southern Puget Basin (Figure 6). It is ranked S1 in Washington and is extirpated from Oregon (SH) and southwest Washington (Natureserve 2004).

The historic and current range estimates the former area of occurrence at approximately 300 km² (BC Conservation Data Centre records 2004). The current extent of occurrence is approximately 2-3 km² and recent vegetation surveys show the current area of occupancy is actually about 50 000 – 60 000 m² (5-6 ha).

Figure 6: Global and Canadian distribution of golden paintbrush

Global historic distribution on left; Canadian distribution on right with star indicating approximate location of extant populations and triangles indicating extirpated populations.

3.6.3 Population and distribution trend

The COSEWIC status report describes three extant ‘populations’ and seven other populations, which have been extirpated or for which there is no recent data (Table 14). One population cited in the status report has subsequently become extirpated leaving only two extant populations. The COSEWIC status report estimates a total population size of 3563 plants. Records from 2002 estimate a total of 8850 although there are differences of opinions regarding this estimate (BC Conservation Data Centre 2004).

3.6.4 Biotic and abiotic features of habitat

The habitat of golden paintbrush consists of mesic maritime meadows. The COSEWIC status report provides information on ecosystem structure, which has been refined with further vegetation surveys (Fairbarns pers. obs. 2004, Chappell 2004a). These meadows are less than 30 m above sea level. Their soils are over 30 cm deep and remain moist throughout the winter months but dry to the permanent wilting point by late summer. The sites have never been ploughed or hayed, but may have been lightly grazed and probably burned in the past.

Trees are rarely present and their abundance and canopy cover is never great due to the combined effects of wind exposure, salt spray and/or the droughty nature of the shallow soils. Shrubs are usually absent or sparse although introduced species (Scotch broom [Cytisus scoparius], spurge laurel [Daphne laureola], gorse [Ulex europaeus]) are occasionally abundant. Native species (tall Oregon-grape [Mahonia aquifoilium], snowberry [Symphoricarpos albus]) are frequent but rarely abundant.

A mix of native and introduced species typically dominates the herb layer. The leading native species are forbs (common camas [Camassia quamash], great camas [C. leichtlinii], wild strawberry [Fragaria virginiana], barestem desert-parsely [Lomatium nudicaule], spring gold [L. utriculatum], bracken fern [Pteridium aquilinum], Pacific sanicle [Sanicula crassicaulis], white triteleia [Triteleia hyacinthina]), although a small component of native graminoids (tufted hairgrass [Deschampsia cespitosa], blue wildrye [Elymus glaucus]) may be present. Introduced grasses (sweet vernal grass [Anthoxanthum odoratum], red fescue [Festuca rubra], Kentucky bluegrass [Poa pratensis], barren fescue [Vulpia bromoides]) and forbs (hairy cat’s ear [Hypochaeris radicata], ribwort plantain [Plantago lanceolata], common vetch [Vicia sativa]) are often present, and any of these may dominate at a given site.

Mosses and lichens are usually sparse in extent, but Cladina portentosa and Dicranum scoparium may be moderately abundant.

3.6.5 Annual cycle

The information in the COSEWIC status report has been updated by subsequent study of plants on Trial Island and casual observations of plants on Alpha Islet (Fairbarns in. prep. a.).

Established plants resprout after the summer/fall drought. Buds on the root-crown break dormancy as early as August if there are late summer rains that moisten the soil. The young shoots may develop rapidly as long as temperatures remain high, and a small proportion of fresh shoots were observed flowering as early as mid-October in 2004.

In typical years, however, the soil doesn’t become sufficiently moist to trigger bud break until mid-autumn, at which point cool temperatures retard shoot growth. Early shoot growth occurs just above the soil surface and the developing shoots have dense internodes and tiny leaves clustered close to the root crown, which are easily overlooked. Shoot elongation begins in late February or March and shoots usually reach full length by late April or early May. Flowering is coincident with the full development of vegetative growth in late April and early May. Green fruit are abundant in June and most fruit have ripened by late July. Seed dispersal begins in late August and continues until late November or early December.

Golden paintbrush is a root parasite (hemiparasite). The association between this species and related hemiparasites and their hosts is a relatively random process and a broad range of species may be parasitized (Atsatt and Strong 1970).

3.6.6 Biologically limiting factors

Seedlings with cotyledons still attached were not observed in natural environments in three years of study but seedlings were observed in March 2004 in an experimental area near the Trial Island plot. It appears either that germination or early juvenile survivorship is a rare event, only occurring in particularly favourable years. It is hard to determine whether low levels of recruitment are due to low germination rates or high levels of early mortality because the seedlings are extremely small and hard to distinguish from those of other species in the area. The potential for recovery of golden paintbrush appears to be limited by intermittent reproduction.

3.7 Prairie lupine Lupinus lepidus var. lepidus

3.7.1 The species

The current taxonomy of prairie lupine is complicated and is not universally accepted. Refer to Douglas and Ryan (1996b) for a description of classification and nomenclature.

Lupinus lepidus var. lepidus is a tufted, perennial herb that grows 20-45 cm tall. Most of the silky leaves grow at the base of the plant with a few alternate leaves along the stem. The leaves are palmately compound, with 5-9 leaflets. The flower is a terminal raceme of pea-like flowers, each 10-13 mm long, ranging in colour from blue, white or purple. The hairy seedpods are 1-3 cm long and contain 2-4 seeds. Distinguishing features include the densely hairy stems and leaves and the woody stem-base (Douglas et al. 1999a; Ryan and Douglas 1996).

3.7.2 Distribution

Ryan and Douglas (1996b) consider the range of prairie lupine to extend from British Columbia south to Washington and Oregon. The distribution in the United States is difficult to determine because of taxonomic confusion and because it is not tracked as a rare species (SNR) in Washington and Oregon. The species is ranked S1 in Alaska but the identification of the specimen has been questioned (Ryan and Douglas 1996b). The species is relatively common in southern Puget Sound prairies (Thurston and Pierce Counties). Although the prairies themselves are highly fragmented and threatened, within the prairies, prairie lupine is common and is a characteristic species of the Roemer’s fescue/white-topped aster (Festuca idahoensis var. roemerii/Sericocarpus rigidus) plant association (Chappell pers. comm. 2004).

In Canada, two prairie lupine populations have recently (BC CDC 2005) been re-confirmed on southeast Vancouver Island at Mt. Braden and Mt. MacDonald. The historical extent of occurrence is difficult to determine because of limited records (BC Conservation Data Centre 2004).

Figure 7: Global and Canadian distribution of prairie lupine

Global distribution on left; Canadian on right with open triangles showing extirpated populations, grey triangles showing unverified populations and solid triangles showing location of recently extant population.

3.7.3 Population and distribution trend

The COSEWIC status report describes 7 extirpated or sites having poor location information. There is no indication of the past total number of plants in Canada.

Since the status report was written, two populations have been confirmed at Mount Braden (1996) in the Sooke Hills Wilderness Area and at Mount Wells Regional Park (2001) (Table 15). No plants were found in subsequent years at the Mount Braden population (Roemer pers. comm. 2004), until July 0f 2005 when 2 plants were seen. At Mount Wells, 7 plants were first observed in 2001 after a burn (BC Conservation Data Centre 2004). In 2003, the site was heavily vegetated with hairy manzanita [Arctostaphylos columbiana] and the alien Scotch broom [Cytisus scoparius] and only 2 plants (one of which flowered with 2 seeds in the seedpod) were found (Maslovat pers. obs. 2003). The plants were not found in 2004, although seed probably still exists in the seedbbank (Roemer pers. comm. 2004). In addition, in July of 2005, 113 plants were found on Mt. MacDonald where the plants had not been seen since 1913 (BC CDC database).

3.7.4 Biotic and abiotic features of habitat

Prairie lupine has been documented from few sites in Canada, so precise habitat descriptions are difficult to determine (Ryan and Douglas 1996b). It tends to occur on very dry, exposed sites with well-drained, nutrient poor, rocky or gravelly soils (Ryan and Douglas 1996b). Prairie lupine populations occurred on level to sloping (20%) ground with elevations ranging from 30-360 metres. At Mount Wells (2001), it was observed in a recent burn area, in flat shallow (< 30 cm) soil. One former site was regularly mowed and another was in a disturbed area between the highway and a railroad (BC Conservation Data Centre 2004).

At Mount Wells, prairie lupine was found in association with resprouting hairy manzanita (Arctostaphylos columbiana), seedlings of red-flowering currant (Ribes sanguineum), gummy gooseberry (Ribes lobbii), oceanspray (Holodiscus discolor), annual grasses and weeds. At Mount Braden, it was observed in patchy Roemer’s fescue (Festuca idahoensis ssp. roemeri), Rhacomitrium canescens and lichens. At Somenos, it was found with Rhacomitrium canescens and large-leaved lupine (Lupinus polyphyllus) with the alien Scotch broom (Cytisus scoparius) on the edges of the population (BC Conservation Data Centre 2004).

In Washington, it appears to prefer water stressed sites that have low soil moisture in the summer (Ewing pers. comm. 2004).

3.7.5 Annual cycle

Prairie lupine is a perennial plant that appears to be short-lived. There is no published information about the phenology or demography of this species. Prairie lupine appears to have a long life in the seedbank (Douglas pers. comm. 2004).

3.7.6 Biologically limiting factors

Without periodic soil disturbance or fires, prairie lupine plants appear to decline over time (Ryan and Douglas 1996b). Adult plants may be dying either due to a lack of vigour in adult plants or due to competition (Ryan and Douglas 1996b).

Other Lupinus species are affected by seed predation (Grosboll pers. comm. 2004) and herbivory (Fagan and Bishop 2000; Fagan et al. 2001) but the effect on prairie lupine is not known. During planting trials in Seattle, Washington, prairie lupine seedlings decreased in size with the addition of mulch and fertilizer and were decimated by an unknown disease (Ewing 2002; Ewing pers. comm. 2004).

3.8 Purple sanicle Sanicula bipinnatifida

3.8.1 The species

Sanicula bipinnatifida Hooker is a well-delineated taxon as described in the status report (Penny and Douglas 2000). Kartesz (1994) does not recognize any infraspecific taxa within this species. Purple sanicle is an erect (10-60 cm tall), branching, taprooted perennial. The basal and lower stem leaves are pinnately divided with a toothed, winged leaf axis. The inflorescence is several to many compact umbels with purple corollas and an inconspicuous involucel. The seeds are egg-shaped schizocarps covered with hooked prickles. Purple sanicle can be distinguished from other sanicle species by its inconspicuous involucel and deep purple flowers (Douglas et al. 1998a; Penny and Douglas 2001).

3.8.2 Distribution

Purple sanicle ranges from southern Vancouver Island, south along the Pacific coast and interior valleys to Baja California (Figure 8). The species is not ranked (SNR) in California, Oregon and Washington (Natureserve 2004). The Georgia Basin-Puget Sound populations appear to be disjunct, by about 100 km, from the main populations, which reach their northern limits along the Columbia River.

Figure 8: Global and Canadian distribution of purple sanicle

Global distribution on left with uncertain distribution in Baja Claifornia; Canadian distribution on right with stars showing location of disjunct population of uncertain status.

In Canada, purple sanicle is restricted to a small area of southeast Vancouver Island and the southern Gulf Islands. Based on the most recent records the extent of occurrence is estimated at approximately 3500 km² and the Canadian area of occupancy 2 to 3ha (BC Conservation Data Centre records 2004; Fairbarns pers. obs. 2004).

3.8.3 Population and Distribution Trend

The COSEWIC status report describes fourteen extant ‘populations’, five that have become extirpated and seven with status unknown (Table 16) (Penny and Douglas 2000). Describing populations separated by less than 1000 m as subpopulations (the default BC Conservation Data Centre criterion for recognizing distinct populations) in addition to subsequent surveys confirm there are there are 20 populations presumed extant, and 5-6 which are presumed extirpated.

The newly recorded subpopulations add to the total estimated population but there is no accurate estimate of the reproductive population. The COSEWIC status report estimates a total population size of 3692 plants, which includes both flowering and non-flowering individuals.

3.8.4 Biotic and abiotic features of habitat

The habitat of purple sanicle consists of mesic maritime meadows in addition to upland meadows. The information in the COSEWIC status report has been supplemented with information from recent vegetation sampling (Fairbarns pers. obs. 2004). These meadows are often less than 30 m above sea level although populations are known from elevations of 100-300 m at Mill Hill, Mount Tzuhalem and Brown Ridge as well as the extirpated population presumed to occur at Mount Douglas. Their soils are over 30 cm deep and remain moist throughout the winter months but dry to the permanent wilting point by early summer. The sites have never been ploughed or hayed, but several have been lightly grazed by livestock and most probably burned in the past.

Trees are sometimes present but their abundance and canopy cover is rarely great due to the combined effects of wind exposure, salt spray and/or the droughty nature of the shallow soils. Shrub cover varies considerably among sites, with the introduced species of Scotch broom (Cytisus scoparius), gorse (Ulex europaeus) and tree lupine (Lupinus arboreus) occasionally abundant.

A mix of native and introduced species typically dominates the herb layer. The leading native species are forbs (Puget Sound gumweed [Grindelia integrifolia], barestem desert-parsley [Lomatium nudicaule], bracken fern [Pteridium aquilinum]), although a small component of native graminoids (California brome [Bromus carinatus], California oatgrass [Danthonia californica]) may be present.

Introduced grasses (soft brome [Bromus hordeaceus], orchard grass [Dactylis glomerata], perennial ryegrass [Lolium perenne], barren brome [Vulpia bromoides]), and forbs (hairy cat’s ear [Hypochaeris radicata], ribwort plantain [Plantago lanceolata], sheep sorrel [Rumex acetosella], small hop-clover [Trifolium dubium], common vetch [Vicia sativa]) are often present, and any of these may dominate at a given site.

Mosses and lichens are usually sparse in extent.

3.8.5 Annual cycle

Information in the COSEWIC status report has been supplemented by subsequent study of plants at Trial Island and Macaulay Point and observations from other Canadian sites (Fairbarns in. prep. d.).

Established plants resprout in January or February. Plants grow slowly through the late winter and early spring, then grow rapidly in April and early May. Shoots begin to wither and die back as the summer drought begins to take hold in mid-May and most shoots are dead by late June or early July.

Flower buds are usually evident by mid-April and flowering peaks in late April and early May. Green fruit are evident by late May and fruit ripen in June. Fruit are shed slowly and many plants retain up to 20% of their fruit until October. The barbed fruit are dispersed when animals brush against the plants.

3.8.6 Biologically limiting factors

Germination occurs between mid-February and mid-April. Initial seedling mortality may be quite high, with few plants developing true leaves. Only a small proportion of germinants survive the succeeding dormant season.

3.9 Seaside birds-foot lotus Lotus formosissimus

3.9.1 The species

Lotus formosissimus Greene is a well-delineated taxon as described in the status report (Ryan and Douglas 1996). Kartesz (1994) does not recognize any intraspecific taxa within this species. Seaside birds-foot lotus is a sprawling perennial (20-50 cm) from stolons or rhizomes. The alternate leaves are pinnately compound with 5 (usually) round to egg-shaped leaflets. The flowers are umbels of 3-9 pink and yellow pea-like flowers. Few seeds are found in the linear to oblong pods. Seaside birds-foot lotus can be distinguished from other Lotus species by the large membraneous stipules on the leaves, perennial habit, and by the yellow and pink colour of the flowers (Douglas et al. 1999a; Ryan and Douglas 1996a).

3.9.2 Distribution

Seaside birds-foot lotus ranges from southern Vancouver Island, south along the Pacific coast to central California (Figure 9). The species is not ranked (SNR) in Washington, Oregon and California (Natureserve 2004). The Canadian populations are disjunct, by about 160 km, from the next nearest populations on the west coast of central Washington State.

In Canada, the historical and current range of seaside birds-foot lotus encompassed approximately a narrow coastal fringe about 60 km long but only about 50 m deep, hence extent of occurrence never exceeded about 3 km². The COSEWIC status report estimates the area of occupancy to be 155 m² although recent estimates place the total area of occupancy in Canada at under 200 m².

Figure 9: Global and Canadian distribution of seaside birds-foot lotus

Global distribution on left with uncertain distribution in Baja California; Canadian distribution on right with stars showing location of disjunct population of uncertain status.

3.9.3 Population and distribution trend

The COSEWIC status report describes two extant populations, one historical population and two populations that were presumed extirpated. Subsequent, fieldwork has confirmed five populations of seaside birds-foot lotus in Canada and one presumed extirpated (BC Conservation Data Centre 2004).

The COSEWIC status report estimates a total population size of 193 plants. Subsequent surveys (Table 17) of some populations indicated that the total Canadian population number between 350 and 600 plants. The precise size of most populations cannot be determined without destructive sampling.

3.9.4 Biotic and abiotic features of habitat

The habitat of seaside birds-foot lotus consists of mesic maritime meadows. The COSEWIC status report provides information on ecosystem structure, which has been supplemented with recent vegetation sampling (Fairbarns pers. obs. 2004). These meadows are less than 30 m above sea level. Their soils are over 20 cm deep and remain moist throughout the winter months but dry almost to the permanent wilting point by late summer. The sites have never been ploughed or hayed, but some have been lightly grazed and most probably burned frequently in the past.

A sparse canopy of Garry oak (Quercus garryana), logepole pine (Pinus contorta), arbutus (Arbutus menziesii) and/or Douglas-fir (Pseudotsuga menziesii) may be present but trees are generally absent due to wind exposure, salt spray and the droughty nature of the shallow soils. Native shrubs are usually sparse or absent although snowberry (Symphoricarpos albus), Nootka rose (Rosa nutkana) and salal (Gaultheria shallon) are sometimes present. These shrub species often form dense thickets at the edge of populations of seaside birds-foot lotus and may advance into the populations in moist years, presenting a threat to the species. Wildfires and First Nations burning may have formerly constrained the advance of these low shrub thickets at some sites. Alien, invasive shrubs such as Scotch broom (Cytisus scoparius), and to a lesser extent gorse [Ulex europaeus] and spurge laurel [Daphne laureola]) are sometimes abundant. These alien species will probably invade the more sheltered locations of seaside birds-foot lotus in the absence of continuing control activities.

A mix of native and introduced species typically dominates the herb layer. The leading native species are forbs (small-flowered birds-foot trefoil [Lotus micranthus], Spanish clover [L. unifoliolatus], two-coloured lupine [Lupinus bicolor], long-spurred plectritis [Plectritis macrocera], dwarf owl-clover [Triphysaria pusilla]), although native graminoids (blue wildrye [Elymus glaucus], California oatgrass [Danthonia californica], long-stoloned sedge [Carex inops]) may be present.

Introduced grasses (common velvetgrass [Holcus lanatus], Kentucky bluegrass [Poa pratensis], sweet vernalgrass [Anthoxanthum odoratum], orchard grass [Dactylis glomerata], soft brome [Bromus hordeaceus], barren brome [Vulpia bromoides], hairgrass [Aira spp.]), are usually more abundant than introduced forbs (ribwort plantain [Plantago lanceolata], hairy cat’s ear [Hypochaeris radicata], smooth cat’s ear [H. glabra], hawkbit [Leontodon spp.], common vetch [Vicia sativa], and small hop-clover [Trifolium dubium]).

Mosses and lichens are usually sparse in extent, but Dicranum scoparium and Cladonia portentosa are occasionally abundant, especially where the seaside birds-foot lotus grows in the shelter of boulders and shallow outcrops.

3.9.5 Annual cycle

The COSEWIC status report provides information on the annual cycle of seaside birds-foot lotus, which has been supplemented from a subsequent study of plants on Trial and Bentinck Island and casual observations from other Canadian sites (Fairbarns in. prep. b.).

Germination occurs in March, April and May depending on weather events and site characteristics.

Established plants resprout after the summer/fall drought. Buds on the buried root-crown break dormancy as early as September if there are late summer rains that moisten the soil. Shoots may emerge from the soil by late September or early October.

In typical years, however, the soil doesn’t become sufficiently moist to trigger bud break until mid-autumn, at which point cool temperatures retard shoot growth. Early shoot growth occurs underground or below the surface layer of moss and plant litter and shoots don’t begin to emerge until late February or March.

Flowering peaks in May and June and most plants bear mature fruit by July. Seed dispersal begins in July, as plants begin to wither, and continues into August, well after most of the foliage has died back. Plants on dry microsites may die, flower, fruit and die-back earlier, but their fruit are often aborted or they bear smaller seeds with less endosperm.

Vegetative growth, flowering and fruiting may be slightly prolonged if unusual summer rainfall events delay the summer drought, but most plants are dormant between mid-August and December.

3.9.6 Biologically limiting factors

Seedling mortality is high, with few plants surviving their first dormant (summer) season. Survivors grow slowly and do not flower in their first year. It is not clear how long plants take to flower.