Recovery strategy for multi-species at risk in Garry Oak Woodlands in Canada
3. Single species background
- 3.1 Deltoid balsamroot
- 3.2 White top aster
- 3.3 Small-flowered tonella
- 3.4 Howell’s triteleia
- 3.5 Yellow montane violet
Last examination and change:
May 2000 (No Change)
Reason for designation:
Few highly reduced populations mainly in threatened Garry oak habitats. At risk from development and competition from exotics.
Designated in April 1996 as Endangered. Status re-examined and confirmed Endangered in May 2000.
Deltoid balsamroot is a member of a genus of about 12 Asteraceae species restricted to western North America (Cronquist 1955). Two species of Balsamorhiza occur in British Columbia (Douglas et al. 1998a). The genus is characterized by yellow ray and disk flowers on scaly receptacles (Bailey and Bailey 1976). Deltoid balsamroot is a perennial with a deep taproot and a woody stem-base. Its leaf blades are usually triangular, prominently nerved, and 10-50 cm long and 10-20 cm wide (Ryan and Douglas 1994, Douglas and Ryan 2001, Douglas et al. 1998a). The involucral bracts are sword-shaped and the 13 to 21 ray flowers are bright yellow. Juvenile plants have smaller, elliptic leaves that are fewer in number than mature plants.
Genetic barriers between the 12 species of Balsamorhiza in western North America appear to be few or absent so that hybrids are usually present where two species come into contact with one another. This has caused some confusion in the delineation of species (Cronquist 1955) although specimens collected along the west coast of British Columbia and the United States are easily identified as deltoid balsamroot.
The ecological role of deltoid balsamroot remains unstudied. This species was a source of food by Coast Salish Indians (Turner 1978). There is also a report of this species being used as chicken feed by early settlers in the Victoria area MacFie (1972). There is no record of the plant being used for other cultural resources (clothing, medicine, ceremonial or symbolic purposes) or ecotourism.
Populations and Distribution
Deltoid balsamroot occurs on the west coast of North America from southwestern British Columbia along the western slopes of the Cascade Mountains in Washington and Oregon to the western slopes of the Sierra Nevada in California (Figure 1, Cronquist 1955, Douglas et al. 1998a). In Canada, deltoid balsamroot is restricted to southeastern Vancouver Island (Figure 1; Douglas et al. 1998a, 2002). The Canadian populations are about 75 km from the nearest populations in Island County (probably Whidbey Island) in Washington (WTU Herbarium Database 2003).
Globally, deltoid balsamroot has a rank of G5, indicating that in most of its range the plant is “apparently common, demonstrably secure and essentially ineradicable under present conditions”(NatureServe 2004). In the U.S. the species is ranked S2 In Washington and SNR (= unranked) in Oregon and California. In Canada, the species has a national rank of N1. Provincially, deltoid balsamroot has been ranked by the Conservation Data Centre as S1 and appears on the British Columbia Ministry of Sustainable Resource Management red list (Douglas et al. 2002). The S1 rank is the most critical rank that can be applied to species at the provincial level and indicates that the species is “critically imperiled because of extreme rarity (typically five or fewer occurrences or very few remaining individuals) or because of some factor(s) making it especially vulnerable to extirpation or extinction.”
Less than 1% of the current global range of deltoid balsamroot occurs in Canada. The historical range of the species is unknown, although it is possible that the historical range and/or population size was larger than estimates of Garry oak woodland habitat loss suggest since MacFie (1972) mentions the species being used for chicken feed by early settlers. To warrant mention as food for chickens suggests a large supply of seeds.
Deltoid balsamroot is known at eight extant (post-1976) sites in British Columbia, with all populations located on southeastern Vancouver Island (Table 8). Seven other historic sites have been extirpated. This represents a loss of 47% of all sites since 1981. The total number of plants currently known in Canada is approximately 1070. Two of the sites contain 90% of all the plants.
Description of Figure 1
Map on left demonstrates Deltoid balsamroot distribution in North America. Map on right demonstrates Deltoid balsamroot distribution in British Columbia.
Population trends are known from only two deltoid balsamroot populations. The site at the Campbell River Indian Reserve was first inventoried in 1992 and then again in 1997, and most recently, in 2004. Over this 12 year period at this site plant numbers have declined from 1700 to approximately 500 (however other observers in 2004 reported 700-900 plants). This decline in the population was mainly due to ongoing degradation of the site by recreational vehicles, invasion by exotic species, and most recently by residential land development (in 2003). A second population, at the Mt. Tzuhalem Ecological Reserve, has remained relatively stable with counts ranging from about 300 in 1991 to 463 in 2004. The increase at the latter site is due to the finding of small additional subpopulations. Annual observations of one Mt. Tzuhalem subpopulation (65-70 plants) over a period of 19 years of have found little change in the population size (Douglas pers. obs.).
The current area of occurrence for deltoid balsamroot is about 1100 km2. This area is most likely be overstated since there is no evidence that the species ever occurred in the area between Campbell River and Mt. Tzuhalem, a distance of approximately 200 km. It is possible that the Campbell River population was established by native peoples from seed collected to the south. The current area of occupancy is 2156 m2. The Tyee Spit site at Campbell River accounts for 87% of this area.
|Collection Site||Last Observation||Collector or Observer||Population (no./area)|
|Tolmie Farm (Victoria)||1891||Newcombe||Extirpated|
|Lost Lake (Victoria)||1916||Newcombe||Extirpated|
|Lake Hill (Victoria)||1926||Walker||Extirpated|
|Royal Oak (Victoria)||1935||Goddard||Extirpated|
|Campbell River, South of||1959||Beamish||Extirpated|
|Witty's Lagoon (Victoria)||1965||Carl||Extirpated|
|Portage Inlet (Victoria)||1976||Brayshaw||Extirpated|
|Thetis Lake (Victoria)||1999||Douglas & Fleming ca.||100/100 m2|
|Francis-King Park, SW of||2001||Douglas||36/30 m2|
|Fort Rodd Hill (Victoria)||2004||Roemer & Turner||4/2 m2|
|Mill Hill, Victoria||2004||Roemer||55/100 m2|
|Beacon Hill Park (Victoria)||2004||Douglas||1/1 m2|
|Tyee Spit, Campbell RiverFootnote a||2004||Douglas & Douglas||500/1875 m2|
|Mount Tzuhalem (Duncan)||2004||Douglas & Richards||463/137 m2|
|Skirt Mountain (Victoria)||2005||Fuller||1/1 m2|
- Footnote A
B. Brooks, T. Ennis and S. Simpson also surveyed this population in 2004 and reported 700-900 plants (Penny pers. comm.. 2005).
Deltoid balsamroot emerges in the spring from its perennial taproot, grows on and flowers by early summer (Douglas and Ryan 2001). By mid-summer, when drought conditions are prevalent, seed set has occurred and the leaves wither and turn brown. By the end of August, the plants have died back to the perennial taproots. Seedlings are not commonly seen in the field. Although seeds are usually relatively easy to germinate, the cultivation of young plants (at least in the garden) in the Victoria area sometimes appears to be difficult (H. Roemer, pers. comm. 2003). Young plants seem to be sensitive to soil moisture conditions and predators (mainly slugs) during the growing season (H. Roemer, pers. comm. 2003). However, in the dry, more typical, deltoid balsamroot habitats, slugs are uncommon.
No information is available regarding the population dynamics of this species in the wild, including the extent to which seed remains viable in the soil, the frequency with which recruitment occurs from established seedlings, and the longevity of mature plants. The identity of pollinators and their importance are not known. Germination rates in both field and laboratory experiments are 70-90%, although seedling development is slow (Ehret et al. 2004, Bailey and Bailey 1997). Seedling survival, in a controlled experiment in the Victoria area, was relatively high, with only a 15% overwinter mortality rate when dormant seedlings were transplanted outdoors (Ehret et al. 2004).
Deltoid balsamroot currently occurs in a range of Garry oak woodland/ rock outcrop habitats in Canada although it is typically associated with very dry, exposed or partially shaded sites with shallow soils (Douglas and Ryan 2001). A Garry oak overstory is often, but not always, present. The essentially open Tyee Spit site in Campbell River has only a single Douglas-fir tree in the meadow, and no Garry oak trees. This site also has different soils than the other sites, as it occurs on coarse, well-drained marine sediments adjacent to the ocean. In contrast, the Mt. Tzuhalem site near Duncan occurs in a relatively moist (at least in spring) ravine with common snowberry, purple sanicle (Sanicula bipinnatifida) and yellow montane violet. Seasonal drought or very well-drained soils seem to be key habitat requirements for deltoid balsamroot.
Associated shrubs include the native common snowberry, and introduced Scotch broom. Herbaceous native associates include: broad-leaved stonecrop (Sedum spathifolium), nodding onion (Allium cernuum) and Menzies’ larkspur (Delphinium menziesii), as well as native and introduced brome species and the introduced sweet vernalgrass (Anthoxanthum ordoratum).
Last examination and change:
May 2000 (No Change)
Reason for designation:
Perennial herb occupying very small patches of habitat at few sites on southeastern Vancouver Island within the threatened Garry Oak Ecosystem where it is at continued risk from development pressures and exotic species.
Designated Threatened in April 1996. Status re-examined and confirmed in May 2000. Last assessment based on an existing status report with an addendum.
White-top aster is a member of a genus of about 250 species, most of which occur in North America (Cronquist 1955). Twenty-three of these Aster species occur in British Columbia (Douglas 1995, 1998a). White-top aster is a rhizomatous, leafy, erect, herbaceous perennial ranging from 10-30 cm tall with broadly lanceolate, alternate leaves 2.5-3.5 cm long (Douglas and Illingworth 1996,1997). Both the lower and upper leaves are reduced. The 5-20 flower heads are borne on short stalks in a terminal inflorescence. The involucres are narrow while the ray flowers are white, few and inconspicuous. The disk flowers are pale yellow with purple anthers. The fruit consists of smooth, densely grey-hairy achenes. White-top aster is easily distinguished from other members of the Aster genus in British Columbia by its few (1-3), short (1-3 mm), white ray flowers that are obscured by the taller pappus.
Populations and distribution
White-top aster is restricted to the Pacific Northwest in North America, occurring from the southeasternn Vancouver Island area in British Columbia to west-central Washington and north-western Oregon (Figure 2, Cronquist 1955, Douglas et al. 1998a). In Canada, white-top aster is known at 21 extant (post-1982) sites in British Columbia with all but two of these populations (Trial Island and Hornby Island) located on southeasternn Vancouver Island (Figure 2). Similarly to deltoid balsamroot, the Canadian populations of white-top aster are about 75 km from the nearest populations in Island County, Washington (WTU Herbarium Database 2003). Approximately 15% of the current global range of white-top aster occurs in Canada.
Globally, white-top aster has a rank of G3, indicating that in most of its range the plant is “rare and local, found only in a restricted range, or because of some other factors making it susceptible to extirpation or extinction” (NatureServe 2004). In the U.S., the species is ranked S2 in Oregon and S3 in Washington. The species has a national rank in Canada of N1. Provincially, white-top aster has been ranked by the BC Conservation Data Centre as S1 and appears on the British Columbia Ministry of Environment red list (Douglas et al. 2002).
Description of Figure 2
Map on left demonstrates White aster distribution in North America. Map on right demonstrates White aster distribution in British Columbia.
The S1 rank is the most critical rank that can be applied to species at the provincial level and indicates that the species is “critically imperilled because of extreme rarity (typically five or fewer occurrences or very few remaining individuals) or because of some factor(s) making it especially vulnerable to extirpation or extinction.”
White-top aster is known at 21 extant (post-1981) sites in British Columbia with all but two of these populations (Trial Island and Hornby Island) located on southeastern Vancouver Island (Table 9). Seven other historic sites have been extirpated. The latter represents a loss of 25% of the known sites since 1887. There are currently 54 800-94 800Footnote 2 stems occurring in Canada. Over 90% of the stems occur at the five locations that each have greater than 3000 stems. The current area of occurrence for white-top aster is approximately 1100 km2. The current area of occupancy is approximately 8020 m2.
Long term population trends are known from only one white-top aster population, at Mt. Tzuhalem. This site has been monitored for eleven years and has decreased from a high of 1350 stems in 1994 to 850 stems in 2004. Part of this decrease is due to the destruction of the largest subpopulation while burning piles of pulled Scotch broom on the ecological reserve.
|Collection Site||Last Observation||Collector or Observer||Population (stems/area)|
|Cedar Hill (Victoria)||1897||Anderson||Extirpated|
|Foul Bay (Victoria)||1914||Macoun||Extirpated|
|Lost Lake (Victoria)||1945||Hardy||Extirpated|
|Knockan Hill Park, west of (Victoria)||1968||Roemer||Extirpated|
|White Rapids Rd. (Wellington)||1982||Ceska||15/5 m2|
|Camas Hill (Sooke)||1985||Ceska||30/4 m2|
|Kangaroo Rd. (Sooke)||1985||Ceska||Not recorded|
|Woodley Range (Ladysmith)||1992||Cadrin||500+/300 m2|
|Francis-King Park, south of (Victoria)||1993||Ryan||Not recorded|
|Mt. Finlayson (Victoria)||1993||Ryan||200/4 m2|
|Uplands Park (Victoria)||1994||Douglas||600/42 m2|
|Harmac (Nanaimo)||1998||Douglas||24 000+/134 m2|
|Francis-King Park (Victoria)||1999||Douglas||438-478/7 m2|
|Bear Hill Regional Park (Saanich)||1996||Illingworth||300/40 m2|
|Cowichan Garry Oak Preserve (Duncan)||1998||Douglas||858/17 m2|
|Downes Pt. (Hornby Island)||1998||Douglas||7 300/10 m2|
|Cordova Bay (Victoria)||2001||Douglas||560/34 m2|
|Port Alberni||2003||Ceska||Not recorded|
|Mt. Tolmie (Victoria)||2003||Ceska||Not recorded|
|Little Saanich Mountain (Saanich)||2003||Fairbarns||12 000-45 000/3 700 m2|
|Mill Hill (Victoria)||2004||Roemer||3 990+/ca 600 m2|
|Mt. Tzuhalem Ecological Reserve (Duncan)||2004||Douglas & Richards||850/120 m2|
|Mt. Wells||2004||Ansell||158/4.5 m2|
|Maple Mountain||2004||Douglas & Richards||20/3 m2|
|Trial Island||2004||Fairbarns||3 000-8 000/3 000 m2|
Each year in April, white-top aster shoots emerge from the rhizomes. Flowering occurs in August, with seeds dispersing a month later (Clampitt 1987). Due to the plant’s rhizomatous habit, white-top aster always occurs in clumps, or colonies. In Washington, colonies average 1-10 m2 and 5-30% of stems bear flowers (Gamon and Salstrom 1992, Thomas and Carey 1996, Bigger 1999). Populations surveyed by Douglas in the 1990’s in BC had higher counts of 30-50% flowering stems, although no seedlings were observed (Douglas and Illingworth 1997). A recent study by Fairbarns at two sites, over two seasons, found very few flowering plants, with only 1-2% of fully developed plants flowering (Fairbarns 2005).
White-top aster is pollinated by a variety of bees and wasps (Giblin and Hamilton 1999, Bigger 1999), as well as a ringlet butterfly (Coenonympha sp.: in the Family Satyridae) (Bigger 1999). Research on white-top aster has been unable to find a correlation between the species’ reproductive biology and its rarity since seed production has been found to be within the normal range for Asteraceae (Clampitt 1987, Giblin and Hamilton 1999, Bigger 1999).
A range of seed viability has been recorded, with results of 13% (Drake and Ewing 1997), 20% (Clampitt 1987), 22% (Ehret et al. 2004) and 39% (Bigger 1999). This range is likely a result of variation among sites and/or years (Bigger 1999). Although white-top aster germination does not appear to be a major problem, seedlings are rarely observed (Clampitt 1987), and have not been observed in BC (Henderson 2005). The plant probably reproduces primarily by vegetative means since seedlings require light to germinate, and also grow extremely slowly in the presence of competitors (Clampitt 1987, Bigger 1999, Giblin and Hamilton 1999). Most research on white-top aster reproduction has supported the hypothesis that the species is an outbreeder, with self-pollination being highly unlikely (Clampitt 1987, Bigger 1999). However, a study by Giblin and Hamilton (1999) has indicated that, although primarily an outbreeder, white-top aster is actually partially self-compatible.
White-top aster is highly stress-tolerant, and is able to persist for long periods once established, even when no seedlings are produced. Clampitt (1987) found that white-top aster exhibited less wilting under droughty conditions, than its exotic competitors [hairy cat's-ear (Hypochaeris radicata), Scouler’s hawkweed (Hieracium cynoglossoides or H. scouleri), and colonial bentgrass (Agrostis tenuis or A. capillaris).
The species’ ability to withstand abiotic stress indicates that once established, white-top aster is likely to persist and Giblin and Hamilton (1999) suggest that white-top aster is an excellent candidate for successful reintroduction to existing and restored prairie habitat. A recent capped landfill restoration in Washington used white-top aster along with other native prairie species and found a 60% white-top aster survival rate after three years (Ewing 2002). However, Clampitt (1993) indicates that the aster is eventually extirpated in moderately or heavily disturbed areas and in areas with a higher percentage of exotics. Clampitt (1987) also speculated that since the aster seedlings grow very slowly, it is possible that they lack the stored resources to grow through soil or plant debris before they unfurl their leaves in the light. White-top aster seeds are more likely to germinate in the spring, rather than the fall (Clampitt 1987), which may be one factor limiting the ability of the plant to reinvade an area, since some of the competing exotic species germinate throughout the winter.
Throughout its range in the U.S., white-top aster is restricted to open or partially open low elevation grasslands. In Washington, the species is found almost exclusively on well-drained, gravely glacial outwash prairies. At the southern limit of the species’ range, in southern Oregon, white-top aster is found in wet tufted hairgrass (Deschampsia cespitosa) grasslands.
White-top aster habitat in Washington has been relatively well studied. Clampitt (1993) noted that the prairies were sparsely vegetated, with a mean vascular plant cover of approximately 81%, in the plots studied. Clampitt (1993) also analysed major associated species to determine that white-top aster was present where Roemer’s fescue (Festuca idahoensis ssp. roemeri) constituted more than 32% cover. The additional presence of four other species [bracken (Pteridium aquilinum), streambank lupine (Lupinus rivularis), sweet vernalgrass, and spikelike goldenrod (Solidago spathulata)] further increased the likelihood of white-top aster presence. This study suggests that white-top aster is a community subordinate that occurs in the gaps between clumps of the bunchgrass, Roemer’s fescue. Another study, at Fort Lewis, Washington, found white-top aster occurring primarily on mounds, small rises and swales of open to partially wooded prairies with greater than 50% cover of native species. The most common native associates were Roemer’s fescue, woolly eriophyllum (Eriophyllum lanatum), spikelike goldenrod and kinnikinnick (Arctostaphylos uva-ursi). Ponderosa pine (Pinus ponderosa) and Garry oak were overstory associates, although white-top aster cover was less abundant under the tree canopy, since it is shade intolerant. White-top aster was also found growing with exotics [Scotch broom, colonial bentgrass, hairy cat's-ear, oxeye daisy (Leucanthemum vulgare), common St. John's-wort (Hypericum perforatum) and ribwort plantain (Plantago lanceolata)], although with lower cover and frequency (Thomas and Carey 1996).
In British Columbia, white-top aster habitat is somewhat different than in the United States. White-top aster in Canada is usually only associated with Garry oak woodlands and is often found on very dry sites. It is not a good competitor, likely partly because of its late flowering, however, white-top aster can withstand extreme conditions including drought and shallow soils. It also requires a southerly or southwesterly exposure. Soils have been described as shallow over bedrock, and vary from shallow dark brown brunisols to brownish-red brunisols (Douglas and Illingworth 1996, 1997). Major associates include sweet vernalgrass, Scotch broom, orchard-grass, oceanspray (Holodiscus discolor), common snowberry, and Pacific sanicle (Sanicula crassicaulis).
The Garry oak woodland in the Cowichan Garry Oaks Preserve is an example of a good white-top aster population. The habitat at this site has been described in detail by Douglas et al. (2001), who classified the site as a Garry oak/orchard-grass plant community with sombric brunisol soils up to a metre in depth that are well aerated, with a high organic carbon content. It is likely that prior to understory dominance by orchard-grass, in this and other Garry oak stands of the region, this plant community would have fallen within the Garry oak/ California brome (Bromus carinatus) community type (Roemer 1972).
In the Cowichan Garry Oaks Preserve, an extremely rich low shrub and herb stratum is present during the spring. The most prominent species are Pacific sanicle and orchard-grass. Other species with moderate to high constancies associated with white-top aster include common camas and great camas (Camassia quamash and C. leichtlinii), brome species (Bromus spp.), broad-leaved shootingstar (Dodecatheon hendersonii ssp. hendersonii), cleavers (Galium aparine) and common snowberry. A marked change in composition takes place by mid-summer. Many of the conspicuous native plants at the site (e.g., common and great camas, broad-leaved shooting star, and yellow montane violet) have completed their yearly life cycle and have essentially disappeared. Perennial grasses that were not recognizable or had not initiated growth in the spring and numerous introduced annuals, well adapted to the drier soils, dominate the understory. At this time, orchard-grass and vetch (Vicia spp.) species are the most prominent, with greatly increased mean covers. Other prominent species include the native grasses, California brome and Alaska oniongrass (Melica subulata) and the introduced grasses: barren brome (Bromus sterilis) and Kentucky bluegrass (Poa pratensis).
Last examination and change:
November 2003 (New)
Reason for designation:
A small annual herb known from a single site in the Gulf Islands, British Columbia. At risk to potential development, exotic species and fire management.
Designated Endangered in November 2003. Assessment based on a new status report.
The small-flowered tonella [Tonella tenella (Benth.) Heller], is a member of a genus of only two species occurring in western North America (Hitchcock et al. 1959). Small-flowered tonella is a slender, ascending to prostrate herb from a delicate taproot (Douglas and Penny 2003a and b, Pojar 2000). The smooth, often branched stems are 5-25 cm tall with 1-2 cm long opposite leaves. The blue or white flowers are small and long-stalked. Fruits are egg to globe-shaped capsules containing 2 to 4, 1-1.5 mm long, wingless seeds.
The ecological role of small-flowered tonella remains unstudied and there is no record of the plant being used for cultural resources (food, clothing, medicine, ceremonial or symbolic purposes) or ecotourism.
Populations and distributions
Small-flowered tonella ranges disjunctly from British Columbia to the species’ main range in southern Washington (Columbia River gorge), through Oregon to central California (Figure 3, Hitchcock et al. 1959, Wetherwax 1993, Pojar 2000. In Canada, small-flowered tonella is known only from a single privately-owned site in on Salt Spring Island in south-western British Columbia (Figure 3). The Canadian populations are about 295 km from the nearest populations in the Columbia River Gorge, south-western Washington (Hitchcock et al. 1959). Less than 1% of the current global range of small-flowered tonella occurs in Canada.
Globally, small-flowered tonella has a rank of G5, indicating that in most of its range the plant is “apparently common, demonstrably secure and essentially ineradicable under present conditions” (NatureServe 2004). In the U.S. the species is ranked SNR (= unranked) in Washington, Oregon and California. The species has a national rank in Canada of N1. Provincially, small-flowered tonella has been ranked by the BC Conservation Data Centre as S1 and appears on the British Columbia Ministry of Environment red list (Douglas et al. 2002). The S1 rank is the most critical rank that can be applied to species at the provincial level and indicates that the species is “critically imperilled because of extreme rarity (typically five or fewer occurrences or very few remaining individuals) or because of some factor(s) making it especially vulnerable to extirpation or extinction.”
Four small subpopulations of small-flowered tonella were recently confirmed in 2002 at the Salt Spring Island site (Table 10). These subpopulations, plus an earlier (1976) collection record, occur in a narrow band extending up a mountainside for approximately 425 m, thus the area of occurrence is about 2 ha. The subpopulations consist of 30 to 150 plants with areas of 1 to approximately 120 m2, respectively. The area of occupancy is 62 m2. Since the plant is inconspicuous and extremely difficult to detect, it is likely other subpopulations occur on the slope.
|Collection site||Last Observation||Collector||Number of plants/area (m2)|
|#1. Upper slope, south||1976||Douglas||Not recorded|
|#2. Upper slope, north||2002||Lomer||56+ /40|
|#4. Lower slope||2002||Douglas||50-80/6|
|#5. Ca. 10 m uphill from beach||2002||Lomer||30 /1|
Description of Figure 3
Map on left demonstrates Small-flowered tonella distribution in North America. Map on right demonstrates Small-flowered tonella distribution in British Columbia.
Species of Tonella, along with its sister genus, Collinsia, of the tribe Collinsieae, are self-compatible annuals (Armbruster et al. 2002). Their persistence at the site in British Columbia indicates that at this time the seeds are viable and germinate readily. Low elevation pollinators for the tribe include bees (Bombus, Anthophora, Emphoropsis, Synhalonia and Osmia spp.) (Armbruster et al. 2002). The phenology of the species has yet to be recorded.
Small-flowered tonella typically occurs on woodland slopes in the U.S., and in Canada is found on a west-facing slope on stable talus. This talus occurs in open bigleaf maple–arbutus forest, where associates include cleavers, little western bitter-cress (Cardamine oligosperma), miner's-lettuce (Claytonia perfoliata), barren brome, and large-flowered collomia (Collinsia grandiflora) or in open Douglas-fir–arbutus–Garry oak forests with Oregon beaked moss (Kindbergia oregana), dicranum moss (Dicranum spp.), Harford's melic (Melica harfordii), upright hedge-parsley (Torilis japonica) and barren brome.
Last examination and change:
May 2003 (New)
Reason for designation:
This is a geographically highly restricted species with a small population occurring at a few scattered sites within remnant Garry oak habitats. It is located within a highly urbanized region with on-going risks to the species from such factors as habitat loss, competition with invasive species, habitat loss, and habitat fragmentation.
Designated Endangered in May 2003. Assessment based on a new status report.
Howell’s triteleia is a perennial herb from a deep, straw-coloured, fibrous-scaly, nearly globe-shaped, bulb-like corm (Pojar 2001). The erect, flowering stem is 20-50 cm tall with one or two smooth, slender, linear basal leaves. The leaves are 20-40 cm long, 3-8 mm wide, sheathed at the base and have entire margins. The flowers consist of six whitish to blue, vase-shaped to narrowly bell-shaped, fused segments forming a 1.5-2 cm long tube. The corolla lobes, which are about as long as the tube, are in two, spreading, petal-like whorls, about as long as the tube. The outer three are broadly lanceolate, the inner three are oblong-egg-shaped and all are slightly ruffled. The fruit consists of a stalked, egg-shaped capsule containing black, rounded seeds.
Howell’s triteleia has a similar appearance to its close relative large-flowered triteleia (Triteleia grandiflora Lindl.). It is distinguished from the latter by its flat filaments which are attached at the same level on the perianth tube (Pojar 2001). The filaments of large-flowered triteleia, in contrast, are not flat and are attached at two levels on the perianth tube.
The ecological role of Howell’s triteleia remains unstudied and there is no record of the plant being used for cultural resources (food, clothing, medicine, ceremonial or symbolic purposes) or ecotourism. Triteleia bulbs may have been dug by aboriginals and used as a starchy food source like other lilies (Turner 1999), however, it is unknown whether Howell’s triteleia has been used for this purpose. Like many other species of Triteleia and Brodiaea, Howell’s triteleia is now available commercially from a United Kingdom nursery.
Populations and distribution
Howell’s triteleia ranges from south-western British Columbia, south through Washington and Oregon to northern California (Figure 4, Keator 1993; Barkworth 1977a). In Canada, Howell’s triteleia is known only from southeasternn Vancouver Island in south-western British Columbia (Figure 4; Pojar 2001, Douglas et al. 2002a).
The Canadian populations are about 15 km from the nearest populations in San Juan County in Washington (Barkworth 1977a).
Globally, Howell’s triteleia has a rank of G5, indicating that in most of its range the plant is “apparently common, demonstrably secure and essentially ineradicable under present conditions” (NatureServe 2004). In the U.S. the species is ranked S1 in California and SNR (= unranked) in Washington and Oregon. The species has a national rank in Canada of N2. Provincially, Howell’s triteleia has been ranked by the BC Conservation Data Centre as S2 and appears on the British Columbia Ministry of Environment red list (Douglas et al. 2002). The S2 rank indicates that the species is imperiled in the province “because of rarity due to very restricted range, very few populations (often 20 or fewer), steep declines, or other factors making it very vulnerable to extirpation from the province” (Natureserve 2004).
Howell’s triteleia is known at 13 extant (post-1998) sites in British Columbia with all of them located on southeastern Vancouver Island (Table 11). Three other historic sites have been extirpated. The latter represents a loss of 19% of the known sites since 1912. There are currently about 1000 plants occurring in Canada. One site, at the Cowichan Garry Oak Preserve, contains 45% of all plants.
The current area of occurrence for Howell’s triteleia is about 50 km2. The current area of occupancy is 3-4 ha. Less than 1% of the current global range of Howell’s triteleia occurs in Canada.
Description of Figure 4
Map on left demonstrates Howell’s triteleia distribution in North America. Map on right demonstrates Howell’s triteleia distribution in British Columbia.
There is little known about Howell’s triteleia in terms of its biology throughout its range. Species of Triteleia generally require well-drained soil and reproduction is through division of the corm, by the production of numerous cormlets, and by seed (Barkworth 1977b). Pollinators are unknown.
Howell’s triteleia occurs mainly on rock outcrops in Garry oak woodlands and in highly disturbed sites dominated by weeds in urban yards and on roadsides. In the highly disturbed sites, dominants include orchard-grass, common vetch (Vicia sativa), rip-gut brome (Bromus rigidus), soft brome (B. hordeaceus), perennial ryegrass (Lolium perenne) and Pacific sanicle, all introduced except for the latter. It is likely that Howell’s triteleia may have occurred in deeper soil sites (similar to the Cowichan Garry Oak Preserve) prior to the widespread loss of this habitat in the Victoria area upon European settlement.
|Collection Site||Last Observation||Collector||Population (no./area)|
|Oak Bay (Victoria)||1912||Beaven||Extirpated|
|Saanich Arm (Victoria)||1919||Newcombe||Extirpated|
|Witty’s Lagoon Regional Park (Metchosin)||1999||Douglas & Penny||43/200 m2|
|Gordon Head (Saanich)||1999||Fontaine||51/5 m2|
|Cowichan River Estuary (Duncan)||2001||Douglas||62/3 m2|
|Cowichan Garry Oak Preserve (Duncan)||2001||Douglas||450/3-4 ha|
|Thetis Lake Regional Park (View Royal)||2002||Ceska||1/1 m2|
|Mt. Tzuhalem, base of (along Knipsen Road)||2003||Janszen||6/0.5 m2|
|Horth Hill Regional Park (North Saanich)||2003||Janszen||3/1 m2|
|Canoe Cove||2003||Fairbarns||2/1 m2|
|Island View Beach||2003||Fairbarns||1/1 m2|
|Beacon Hill Park (Victoria)||2004||Fairbarns||ca. 200/12 m2|
|Somenos Lake (Duncan)||2004||Roemer||126/140 m2|
|Albert Head (Metchosin)||2004||Roemer||9/2 m2|
|William Head Rd. (Metchosin)||2004||Milne||14/10 m2|
The Garry oak woodland in the Cowichan Garry Oak Preserve contains the best example of a Howell’s triteleia population. The habitat at this site is described above in the white-top aster background (section 3.2).
Howell’s triteleia also occurs in a mixed Garry oak–arbutus stand at the base of rock outcrops on Horth Hill. The shrub layer is more prominent at this site than it is at the Cowichan Garry Oak Preserve, and is dominated by tall Oregon-grape (Mahonia aquifolium) and oceanspray. Associates include hairy honeysuckle (Lonicera hispidula), rip-gut brome, cleavers, small-flowered nemophila (Nemophila parviflora) and hedgehog dogtail (Cynosurus echinatus).
violet, yellow montane
Viola praemorsa ssp. praemorsa
Last examination and change:
May 2000 (No change)
Reason for designation:
Highly localized species with few sites and restricted to habitats under threat from development, recreational use and from spread of exotic plants.
Designated Threatened in April 1995. Status re-examined and confirmed in May 2000. Last assessment based on an existing status report.
Yellow montane violet is a perennial from a fibrous root, ranging from 6 to 25 cm tall with broadly lanceolate, sparsely to densely hairy, mainly basal leaves, with blades 2 to 10 cm long (Ryan and Douglas 1995, Douglas et al. 2000). The yellow, terminal flowers are solitary on one to several, erect stems. The fruit is a smooth to hairy capsule with dark brown seeds. Among the yellow violets which occur in western British Columbia, yellow montane violet is distinguished primarily by the slightly serrate, ovate-lanceolate, pubescent leaves. The only other plant occupying similar habitats that superficially resembles flowerless yellow montane violet, is the introduced ribwort plantain (Plantago lanceolata). The latter has leaves which are similar in colour and shape to those of yellow montane violet but usually lack hairs and gradually taper to the petiole.
The ecological role of yellow montane violet remains unstudied and there is no record of the plant being used for cultural resources (food, clothing, medicine, ceremonial or symbolic purposes) or ecotourism.
Populations and distribution
Yellow montane violet occurs on the west coast of North America from south-western British Columbia to northern California (Figure 5, Hitchcock and Cronquist 1961, Little 1993). In Canada, yellow montane violet occurs on southeasternn Vancouver Island and adjacent Salt Spring Island (Figure 5; Douglas and Ryan 1998, Douglas et al. 2002). The Canadian populations are approximately 30 km from the nearest populations in San Juan County, Washington.
Description of Figure 5
Map on left demonstrates Yellow montane violet distribution in North America. Map on right demonstrates Yellow montane violet distribution in British Columbia.
Globally, yellow montane violet has a rank of G5T3T5, indicating that in most of its range this subspecies ranges from “vulnerable” to “apparently common, demonstrably secure and essentially ineradicable under present conditions” (NatureServe 2004). In the U.S., the species is ranked SNR (= unranked) in Washington, Oregon and California. The species has a national rank in Canada of N1. Provincially, yellow montane violet has been ranked by the BC Conservation Data Centre as S1 and appears on the British Columbia Ministry of Environment red list (Douglas et al. 2002).
The S1 rank is the most critical rank that can be applied to species at the provincial level and indicates that the species is critically imperilled because of extreme rarity (typically five or fewer occurrences or very few remaining individuals) or because of some factor(s) making it especially vulnerable to extirpation or extinction.
Yellow montane violet is known from 13 extant (post-1996) sites in British Columbia with all but two of these populations (on Salt Spring Island) located on southeastern Vancouver Island (Table 12). Five other historic sites have been extirpated. In addition, three sites, last seen between 1961 and 1977, remain unconfirmed. Therefore, 38% of the known sites have probably been extirpated since 1977. There are currently about 45 000 plants occurring in Canada. One site, at Somenos Lake, contains 88% of all plants that occur in Canada.
The current area of occurrence for yellow montane violet is about 330 km2. The current area of occupancy is approximately 18 870 m2. Less than 1% of the current global range of yellow montane violet occurs in Canada.
Yellow montane violet is a perennial species which overwinters as a short vertical rhizome. In British Columbia, the violet, as with many other forbs located in Garry oak communities, appears to take advantage of the warm temperatures, ample moisture, and high light levels found during spring. In early spring (March), the leaves emerge, followed by the appearance of flowers in April and May. This usually occurs before the Garry oak leaves have fully emerged and before grasses, which usually dominate the understory, have grown to a sufficient size where they shade or smother yellow montane violet and other forbs. Seeds are explosively ejected from the capsules during early to mid-summer and most plants then dieback to the perennating rhizome (underground stem which persists more than one growing season). Some plants retain their leaves and produce elongated decumbent (lying on ground but with tip ascending) stems which may exceed 25 cm in length. Eventually these plants will also wither and die back to the perennating rhizome (Ryan and Douglas 1995).
|Collection Site||Last Observation||Collector/ Observer||Population (no./area)|
|Cedar Hill (Victoria)||1887||Macoun||Extirpated|
|Prospect Lake (Saanich)||1921||Harvey||Extirpated|
|Holmes Point (Comox)||1961||Beamish||Unknown|
|Mount Tolmie (Victoria)||1963||Young||Unknown|
|Nanoose Hill (Nanaimo)||1976||Douglas||No original data; 2004 search unsuccessful; almost certainly extirpated|
|Mary Hill (Metchosin)||1977||Ceska||Unknown|
|Mt. Maxwell (Salt Spring Island)||1985||Roemer||No original data; 2001, 2003, 2004 search unsuccessful; may be extirpated|
|Rithet’s Bog||1987||Ring||Probably extirpated|
|Beacon Hill Park (Victoria)||1997||Douglas||465/1 000 m2|
|Smith Hill (Victoria)||1997||Douglas||490/435 m2|
|Uplands Park (Victoria)||1997||Douglas||95/18 m2|
|Falaise Park (Victoria)||1997||Douglas & Mothersill||59/10 m2|
|Cowichan Garry Oak Preserve (Duncan)||2000||Douglas & Penny||3 205/10 828 m2|
|Playfair Park (Saanich)||2000||Douglas & Penny||282/305 m2|
|Mount Tzuhalem (Duncan)||2001||Douglas||55/115 m2|
|Christmas Hill (Saanich)||2001||Penny||86/136 m|
|Bear Hill Regional Park (Saanich)||2001||Fraser||78/6 m2|
|Little Saanich Mountain (Saanich)||2004||Fairbarns||25/15 m2|
|Mount Tuam (Saltspring Island)||2004||Douglas & Smith||53+/400 m2|
|St. Peters Church (Duncan)||2004||Douglas & Smith||5/0.5 m2|
|Somenos Lake (Duncan)||2004||Douglas||40 000+/5 600 m2|
Yellow montane violet does not appear to spread by either stolons or rhizomes hence, seed production appears to be very important in the maintenance and spread of this species into new habitats. Observations by M. Fairbarns (pers. comm.) indicate that seeds are likely dispersed by ants since the seeds bear what appear to be elaiosomes (lipid-rich structures that attract ants), as well as through ballistic dispersal (explosive opening of the fruit). Both methods probably do not facilitate seed dispersal more than approximately one metre.
Like other Viola species, the yellow montane violet may also produce seeds by cleistogamous flowers. These are apetalous (lacking petals) flowers, containing both stamens and ovules, which do not open but produce seeds by self-pollination. They emerge after the petalous flowers have completed flowering. The extent to which yellow montane violet produces cleistogamous flowers and the importance of their contribution to seed production is not known.
There is little direct information on the importance of insect pollinators, the proportion of flowers which are self- and cross-pollinated, and the average number of viable seeds produced by individual plants. Pollination of the closely related species, Nuttall’s violet (V. nuttallii), is by solitary bees and occasionally by butterflies. Despite its broad distribution, there is no indication that pollinators differ between ecogeographical regions (Beattie 1974). Beattie (1974) believes that Viola flowers are pollinated by a wide variety of both medium- and long-tongued pollinators. Davidse (1976) has observed flies of the genera Eristalis and Bombylius (drone flies and bee flies) frequently and indiscriminately visiting the yellow-flowered violets: yellow sagebrush violet (Viola vallicola), Utah violet (V. utahensis) and upland yellow violet [V. praemorsa ssp. major (=V. praemorsa ssp. linguifolia)].
In British Columbia, yellow montane violet occupies a number of different habitats in Garry Oak communities and grass-dominated meadows. Yellow montane violet is predominantly found in Garry oak communities with deeper soils and less exposed bedrock, typically with a southerly exposure on slopes ranging from relatively flat (0-5% slope) to steep (25-50% slope). These sites tend to be somewhat mesic in the spring, although they may become very dry in the late summer. Sites also contain a substantial number of other forbs including white triteleia (Triteleia hyacinthina) and western buttercup (Ranunculus occidentalis) but tend to be dominated by a mixture of introduced grasses such as early hairgrass, orchard-grass, hedgehog dogtail, and sweet vernalgrass, and several species of brome. Some stands are dominated in the understorey by shrubs, in particular, common snowberry and Scotch broom, which effectively shade out many herbaceous species. Soils are usually orthic sombric brunisols (Roemer 1972).
The Garry oak woodland in the Cowichan Garry Oak Preserve contains one of the best examples of a yellow montane violet population. The habitat at this site has been described in detail by Douglas et al. (2001) and a summary of this habitat appears in the white-top aster section. The largest yellow montane violet population occurs at Somenos Lake, where it occurs on two sides of an open meadow along with brome species, under an open Garry oak canopy. Other associated native species include: mountain sweet-cicely (Osmorhiza berteroi), slender toothwort (Cardamine nuttallii), broad-leaved shootingstar, and Erythronium oregonum (Ryan and Douglas 1994).
Some populations are also located on relatively steep rocky slopes where Garry oak–oceanspray is the dominant vegetation type. On these sites, they are usually located in pockets of deep soil partially shaded by Garry oak. Yellow montane violet may occasionally be found in open grass-dominated meadows where soils are relatively deep and likely retain some moisture during summer drought conditions (such as at Somenos Lake). On less optimum sites, such as at Mt. Tuam where soils are very shallow and vegetation is heavily grazed by sheep, plants are noticeably smaller in size.
- Footnote 2
Abundance estimates of white-top aster populations are problematic. The numerous stems appear at regular intervals along one to two m, or more, rhizomes and individual plants are impossible to estimate without excavating. Stem counts therefore give only an approximate estimate of relative abundance between populations. In addition, some observers of large populations (e.g., Fairbarns, see Table 10) have recorded broad ranges only, likely due to practical time considerations.
- Date Modified: