The story of Coastal Douglas-fir forests: Some of the most rare and diverse plant communities in Canada

Coastal Douglas-fir forests and associated ecosystems exist at the interface between land and water on the edge of the Salish Sea. With a long legacy of land stewardship by Coast Salish Nations, the ecological communities characteristic to this region are abundant and diverse. Since non-Indigenous arrival in the area, aggressive land conversion due to logging and development has dramatically reduced and fragmented a once lush landscape. 

To paint a picture of what the CDF looked like historically, how it has changed over time, and what we can do to safeguard and enhance what remains, Shauna Doll, Raincoast’s Gulf Islands Forest Project Coordinator, has interviewed experts from different backgrounds and disciplines to collect different understandings of this assemblage of ecosystems. This interview with Jason Straka, RPBio, is the first installment in our ongoing series on the story of the CDF. 

How would you describe the ecological communities characteristic to the CDF?

There are plenty of ecological communities that can be found in the CDF, but the ones that I would call characteristic include forests dominated by Douglas-fir, grand fir, and western redcedar with an understory of shrubs like salal, Oregon grape, oceanspray, and often a thick layer of mosses, like Oregon beaked moss (Kindbergia oregana).  Other plants that can be abundant are baldhip rose, snowberry, and vanilla leaf. Drier sites can have iconic broadleaved trees like Garry oak and arbutus and some of these sites are associated with incredibly diverse herbs that provide awesome displays of wildflowers in the spring on rocky bluffs and meadows.  I should also give a shout out to some of the work that has been done on bryophyte communities of these ecosystems, which can be distinctive and diverse. 

What are some unique features of the CDF zone?

Climate is important in defining what is considered the CDF zone, and it is essentially the mildest climate in Canada.  The CDF occurs in the rain shadow of Vancouver Island and the Olympic mountains, which results in warm, dry summers and relatively mild, wet winters. Keen gardeners all know that the growing seasons are long but summers can bring extremely dry conditions. This unique climate helps support some of the most rare and diverse plant communities in Canada.  

In addition to climate, I think it’s important to recognize that the ecological communities of the CDF have been, and continue to be, shaped by humans. Indigenous people have been here managing this ecosystem since time immemorial.  More recently, settler colonialism and processes like fire suppression, changes in hunting patterns, agriculture, forestry, and urban development have all heavily modified the ecosystems we see today.

What makes the CDF zone so diverse?

I think it’s a mix of a unique climate, gnarly geography, and glacial history, helped along by land-managers, that has allowed so many species to arrive here, evolve here, and persist over time.  Indigenous knowledge has been instrumental in maintaining diversity in the CDF over time.

What are some of the most interesting or rare plant and animal species one might encounter within the CDF zone? Are there any endemic species?

Oh yes, there are plenty!  How many do I get to choose?!  I’ve recently been enjoying some species associated with seepage sites and vernal pools.  These are species that are often overlooked because they are small, ephemeral, and require very specific habitats to survive.  Last weekend I spent some time with a friend hunting down Macoun’s meadowfoam.  This is a plant that looks deliciously green, lush, and succulent around this time of year, and then dries out during the summer to the point where there is no identifiable trace of it until the next spring.  A few other species like this are Victoria’s owl-clover (a global endemic), and bearded owl-clover, both of which are neither owls nor clovers but are beautiful little plants. They’re also at least partially parasitic on other plants, which I think is pretty cool.  I’ve yet to find a blue-grey taildropper slug, which is perhaps near the top of a highly contentious list of charismatic slugs of BC, but it doesn’t stop me from looking for them or being excited about them. Some recent work led by Dr. Shannon Berch is revealing that there are more species of fungi than we previously knew, many of which are likely endemic to the CDF.

About Jason

Jason Straka, MSc, RPBio, is an ecologist, biologist, and educator with over a decade of experience working to inventory, conserve, and promote biodiversity in hotspots across Canada. Jason is the Program Ecologist with the BC Conservation Data Centre. Descended from Slovak grandparents, he has a deep and enduring love of debating ecological classification, hunting for fungi, and consuming root vegetables.

References

Austin, M. A., D. A. Buffet, D. J. Nicholson, and G. G. Scudder. 2008. Taking nature’s pulse: the status of biodiversity in British Columbia. Biodiversity BC, Victoria. British Columbia, Canada.

Erickson, W. R. 1993. Garry Oak Ecosystems. BC Ministry of Environment Lands and Parks, Wildlife Branch.

Flynn, S. 1999. Coastal Douglas-fir Ecosystems. BC Ministry of Environment Lands and Parks, Wildlife Branch.

Green, R. N., and K. Klinka. 1994. A field guide to site identification and interpretation for the Vancouver forest region. Land management handbook number 28.

Tucker, D., and C. L. Farge. 2021. Bryophyte communities in Quercus garryana ecosystems on South East Vancouver Island: Preliminary mesohabitat assessment. The Bryologist 124:198–217.

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