Plant communities - Coastal Douglas-fir communities

DOUGLAS-FIR/GARRY OAK - ONIONGRASS (Pseudotsuga menziesii/Quercus garryana-Melica subulata)

Status

This community has a very small range and, historically, occurred infrequently in the natural landscape. It has been fragmented and depleted by urbanization and agricultural conversion. There are only a few occurrences in protected areas, and the level of protection and management in some of these areas is insufficient. Development pressures, including the establishment of new woodlots, seriously threaten remaining occurrences of this community.

Ecology

This forest community has an open canopy of Pseudotsuga menziesii (Douglas-fir) and Quercus garryana (Garry oak). The shrub layer is sparse; Lonicera hispidula (hairy honeysuckle) is usually present. The herb layer is dominated by Melica subulata (Alaska oniongrass), with Carex inops (long-stoloned sedge), Sanicula crassicaulis (Pacific sanicle), Moehringia macrophylla (big-leaved sandwort), Dodecatheon hendersonii (broad-leaved shootingstar), Trisetum cernuum (nodding trisetum), and Galium aparine (cleavers). Rhytidiadelphus triquetrus (electrified cat's-tail moss) is the dominant moss.
This community occurs on dry sites over inactive colluvial and sometimes morainal parent materials. Soils are shallow, mostly sandy loamy, often with moderate coarse fragments, and are classified as Sombric Brunisols. Soil moisture is rated as very dry and the soil nutrient regime is rich to very rich.

Distribution

This community is restricted to low elevations along southeast Vancouver Island from Bowser to Victoria, and may also occur on the southern Gulf Islands. Elevational limits range from near sea level to approximately 150 m. It is now considered to be extirpated from the State of Washington.

Ecoprovince: Ecosections

GED: NAL, SOG, SGI

Biogeoclimatic unit

CDF: CDFmm/03

Broad ecosystem unit

GO (CD)

Structural stages

All stages

Selected references

Eng, M. 1992. Protected areas on Vancouver Island: An analysis of gaps in representation
for conservation purposes. B.C. Min. For., Victoria, B.C. 1991/1992 Progress Rep., EP 1145.

Erickson, W.R. 1996. Classification and interpretation of Garry oak (Quercus
garryana) plant communities and ecosystems in southwestern British Columbia. Univ. Victoria, Dep. Geog., Victoria, B.C. MSc thesis.

Garry Oak Meadow Preservation Society. 1995. Symposium on Rehabilitation of Garry
Oak Grasslands, June 10, 1995. Victoria, B.C.

Green, R.N. and K. Klinka. 1994. A field guide to site identification and interpretation for
the Vancouver Forest Region. B.C. Min. For., Victoria, B.C. Land Manage. Handb. No. 28.

Southeast Vancouver Island Sensitive Ecosystems Inventory. (In progress). B.C.
Conserv. Data Centre, B.C. Min. Environ., Lands and Parks, and Environ. Can., Qualicum Beach, B.C.