Management Plan for Coastal Wood Fern in Canada [Final] 2011: Species Status Information
Coastal wood fern[1]
Legal Designation
- Identified Wildlife:[2] No
- B.C. Wildlife Act: [3] No
- SARA Schedule: 1 (2003)
B.C. Rank: S2S3 (2000)
B.C. List: Blue
Global Rank: G5 (1999)
COSEWIC: Special Concern (2001)
Subnational Ranks[5]: AZ: S2; All other states (WA ; OR; CA; MO): SNR
B.C. Conservation Framework (CF)[6]
Goal 1: Contribute to global efforts for species and ecosystem conservation. Priority:[7] 3
Goal 2: Prevent species and ecosystems from becoming at risk. Priority: 6
Goal 3: Maintain the diversity of native species and ecosystems Priority: 2
CF Action Groups: Compile Status Report; Send to COSEWIC; Planning; Monitor Trend; Habitat Protection; Habitat Restoration; Private Land Stewardship
1 Data Source: B.C. Conservation Data Centre (2010) unless otherwise noted
2 Identified Wildlife under the Forest and Range Practices Act
3 Listed as Endangered or Threatened under theWildlife Act
4 S = Subnational; N = National; G = Global; B= Breeding; X = presumed extirpated; H = possibly extirpated; 1 = critically imperiled; 2 = imperiled; 3 = special concern, vulnerable to extirpation or extinction; 4 = apparently secure; 5 = demonstrably widespread, abundant, and secure; NA = not applicable; NR = unranked; U = unrankable
5 Data Source: NatureServe (2009)
6 Data Source: Ministry of Environment (2010)
7Six-level scale: Priority 1 (highest priority) through to Priority 6 (lowest priority)
The coastal wood fern is an evergreen fern, 20–60 cm tall, which grows in vase-like clusters from a stout, short, creeping rhizome (Figure 1). The oblong lanceolate-shaped leaves are twice divided with deeply cut pinnae (primary division of a compound frond with leaflets on both sides of a central axis). The pinnules (secondary leaflet in a bipinnately compound frond) have small, spiny teeth along the margin. The rhizomes, stipes, and undersides of the pinnae have lance-shaped, chestnut-coloured scales (Douglaset al. 2000).
Figure 1. Illustration of the coastal wood fern. Used with permission from the University of Washington Press (Hitchcock et al. 1969. Illustrations by Jeanne R. Janish).
The coastal wood fern is found along North America's west coast in British Columbia (B.C.), Washington, Oregon, and California; and inland in Montana and Arizona (NatureServe 2006). The Montana populations were not noted in the status report (COSEWIC 1998). The B.C. populations are approximately 250 km distance (disjunct) from the closest populations in Snohomish County, Washington State. Figure 2 outlines the North American distribution of this species.
Figure 2. North American distribution of coastal wood fern (from COSEWIC 1998)
In B.C. the distribution of the coastal wood fern is limited to eastern Vancouver Island and several adjacent northern Gulf Islands, including Denman and Hornby islands and several smaller islands in the Ballenas / Winchelsea Archipelago off the coast of Nanoose Bay (Figure 3) (COSEWIC 1998; B.C. CDC Element Occurrence Records 2006). The populations occur in a narrow rectangle measuring 6 km wide by 50 km long, totaling approximately 300 km2, with large expanses of water between populations. The area of occupancy for the coastal wood fern from Conservation Data Centre (CDC) records and recent surveys is approximately 1.9 ha.
B.C. supports less than 1% of the global abundance of this species. As of 2007, the total number of plants in B.C. is approximately 7500 (B.C. CDC Element Occurrence Data 2006; Maslovat, pers. obs. 2007).
Figure 3. Distribution of coastal wood fern in B.C. and Canada. Numbers for populations on Denman and Hornby Islands correspond to population names listed in Table 1.
There are 13 recorded populations in B.C. (Table 1) rather than 18 populations as listed in the status report (COSEWIC 1998). One location at Mount Finlayson, in Goldstream Provincial Park is unconfirmed and is not addressed in this management plan. Therefore, there are 12 extant populations in British Columbia.
Although two additional populations were found after the status report was written (B.C. CDC Element Occurrence Data 2006), some of the populations listed in the status report are now treated as subpopulations, since they are less than 1 km apart (a criteria used by the CDC for distinguishing populations). In this report, subpopulations less than 1 km apart are combined into one subpopulation, except for Amelia and Gerald islands, which are treated as separate populations because they are geographically isolated by the ocean.
(Note: With the exception of Henry (1915) the references in this table are denoting herbarium specimen collector and date, and not actual publications.)
Summary of land tenure of known populations
- 6 private
- 1 private + provincial park
- 1 private + DND
- 1 private + camping co-op and conservancy association
- 2 provincial parks + Goldstream Park (Mt. Finlayson) unconfirmed historical population
- 1 provincial Crown land
In Canada, the coastal wood fern is limited to the Coastal Douglas-fir Biogeoclimatic Zone, moist maritime subzone (CDFmm) (B.C. CDC 2006). The coastal wood fern grows in coastal wooded slopes under open forest canopies of Douglas-fir (Pseudotsuga menziesii), Garry oak(Quercus garryana) or arbutus (Arbutus menziesii), and on rocky coastal bluffs and outcrops with stunted Garry oak (Quercus garryana) and oceanspray (Holodiscus discolor) (COSEWIC 1998; B.C. CDC Element Occurrence Records 2006). Plants growing on rocky outcrops and coastal cliffs show more signs of stress than plants found in coastal wooded habitats, such as smaller leaf blades and chlorosis (COSEWIC 1998). Plants growing in exposed habitats have also been observed to be less successful at overwintering (Martin, pers. comm. 2007).
Site aspect ranges generally from southwest to southeast, and one subpopulation occurs in a site with an east aspect. Elevation ranges from 0 to 120 m. Most populations occur on steep slopes, which range from 0 to 80%. Soils are mostly very dry to moderately dry, rapidly drained, and with moderate levels of nitrogen (COSEWIC 1998; B.C. CDC Element Occurrence Records 2006).
Information concerning the biology and ecology of the coastal wood fern is limited. Plants take 1–5 years to reach maturity and each fertile blade can produce as many as 13.5–15 million wind-dispersed spores. Some of the spores are retained on the blades over the winter and released the following spring. Spore viability averages three years or more for other Dryopteris species. In other fern species, spore germination, early gametophyte development, and gamete fusion occur when soils are moist in early spring (COSEWIC 1998). In California, coastal wood fern young sporophytes are found only in shaded areas with bare mineral soil (Veilleux, pers. comm. 2007). No prothalli (leaf-like structure bearing sexual organs) were noted during recent winter surveys in B.C., although survey time may not have been ideal (Maslovat, pers. obs. 2007).
The coastal wood fern can also reproduce vegetatively by rhizome elongation. Vegetative reproduction appears to be more common in dry, rapidly drained sites that are not ideal for spore germination and gamete fertilization (COSEWIC 1998).
The coastal wood fern is difficult to propagate ex situ from spores (Fraser, pers. comm. 2007; Furman, pers. comm. 2007; Wilson pers. comm. 2007). Horticultural propagation is via division of rhizome offshoots in the spring or autumn (Leigh 1999; Furman, pers. comm. 2007; Wilson, pers. comm. 2007).
Demographic collapse. The degree of sexual reproduction of the coastal wood fern in Canada is not known and may be a limiting factor. Although survey times were not ideal for finding prothalli, no evidence of sexual reproduction was found during winter surveys of Denman and Hornby Island populations (Maslovat, pers. obs. 2007). The ability of coastal wood fern populations to rebound from disturbances or extirpation may be hampered by a lack of sexual reproduction. There is a low probability this will influence recovery or management potential for the species.