Garry oak ecosystems: more than just an oak tree

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a garry oak tree with its mottled bark

Since moving to Canada and specifically Vancouver Island, I’ve learned a lot about the Pacific Northwest and its environments, ecosystems and geology. One of my favorite ecosystems and landscapes is the garry oak meadow or the garry oak ecosystem. As the name implies, the foundation of this zone is the garry oak tree (Quercus garryana). An ecosystem, however, by definition is not just a tree. Its a whole community of all the creatures living in the area and how they interact.

These meadows are unlike anything I grew up around out east or many places I’ve seen since. I think that’s why I like them so much; not to mention they are so full of life (especially birds)! Southeastern Vancouver Island is one of the only places in Canada to have the garry oak ecosystem. In the U.S., garry oaks are found along the western edge of the Cascades in Washington and Oregon and into northern California. The garry oak is the only native species of oak in this region.

Living in a rain shadow area with dry summers, the garry oak is drought-tolerant and fire-resistant and prefers well-drained soil (GOERT). The tree are often successful in areas with shallow soil and rocky outcrops; most remaining modern garry oak ecosystems are rockier sites (ICOR, University of Victoria).

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a garry oak stand in the summer

Because there is a variety of sub-environments in a garry oak ecosystem like woodlands, savannah, meadows and vernal pools, there is the potential for high biodiversity. Much of the Greater Victoria region was naturally a garry oak ecosystem, but with European colonization much of the landscape was lost for development in the last 200 years (see map). With the loss of much of the garry oak habitat with European settlement, some species like the Western Bluebird and Lewis’s Woodpecker became extinct on the island.

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Black-tailed Deer thrive in garry oak habitat
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Map of Greater Victoria with previous garry oak ecosystems in 1800 (green) and those remaining in 1997 (red). Map by Lea, T., Horth, D., Richards, D. and T. Brierly, retrieved from GOERT.

One of the best things about garry oak ecosystesm (okay, I’m biased) are all the birds! Birds are abundant in these areas during all four seasons. Common birds I see are Anna’s Hummingbirds, Spotted Towhees, sparrows (particularly Golden-crowned, White-crowned & Song), a wide variety of warblers, Red-breasted Nuthatches, woodpeckers, Bald Eagles and Turkey Vultures flying overhead, swallows (Barn and Tree) and Bewick’s Wrens. Invasive birds in garry oak meadows are European Starlings and House Sparrows, both of which displace native cavity nesters.

Garry oak commonly co-exist among Douglas Fir trees and Arbutus trees (Canada’s only broadleaf evergreen tree). Other common plants in garry oak meadows I have learned are camas, fawn lilies, Henderson’s Shooting Star, wild rose and buttercups. Scotch broom (or gorse) and English ivy are two of the top invasive culprits taking over.

Some places to see a variety of intact garry oak ecosystems around Victoria includes: Mt. Tolmie, Uplands Park, Beacon Hill Park, Mt. Douglas and Little Mt. Douglas, Francis King Park and Fort Rodd Hill. Many of the Gulf Islands have beautiful areas of garry oak habitat as well.

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garry oak grove in early autumn at dusk
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garry oak meadow in the winter

Resources
Garry Oak Ecosystems Recovery Team
University of British Columbia Geography Department
University of Victoria Geography Department

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