The shores of Pacific Rim provide a diverse range of vegetation. From the ocean’s edge to rocky crevices and sand dunes, each community is adapted to the stresses imposed by its location.
The forelog zone is found between the open sand beach and the driftlogs. Vegetation is limited to clumps of sea rocket and sandwort in this area most subject to the action of tides and waves. The driftlog zone is cluttered with an accumulation of logs and other flotsam deposited by tides and storms. Beach rye, beach pea and giant vetch grow among the logs furthest from the water’s edge.
The postlog zone is more stable than the two preceding zones. It supports European beach grass and rye grass on its seaward side and Nootka rose, willows, black twinberry and salal as it leaves the beach and becomes the spruce fringe community. Within this zone some areas of sand dunes have developed. These areas, by contrast, are constantly changing. Root networks of plants such as mace-headed sedge help to stabilize shifting dunes. Other vegetation such as yellow sand verbena and beach morning glory establish themselves in deeply rooted, widespread clumps, contributing to the stabilization of dune systems. On its outer fringes, kinnikinnick, a mat-forming shrub, accumulates a layer of organic matter that forms the base for eventual soil development and a seedbed for the slow invasion of the adjacent forest community.
Along the shoreline, exposed rocky headlands and islets provide little soil substrate for vegetation. Plants establish themselves above the reach of high tides but are still exposed to heavy salt spray and wind. Rock cracks offer refuge for hardy cinquefoils, plantains and thrift at the margins of the spruce fringe. Selfheal, nodding onions and beach strawberry commonly establish themselves in soil pockets, with scattered patches of yellow- and blue-eyed grasses, stonecrop and Indian paintbrush.
While shrubs are not common in this area, saskatoon berry, Nootka rose and salmonberry can be seen hugging the transition between rocky shoreline and forest. Tree cover is missing except for the occasional wind-stunted spruce or cedar high up on the rocks. In more sheltered regions between rocky headlands, silverweed, glasswort, and rush fringe cobble and shell-type beaches.
Salt marsh, where the land is periodically invaded by the sea, is dominated by grasses and sedges. Where the marsh is cut by stream and tide channels, mud flats host a rich profusion of eel grass. This grass is integral to the estuarine community, providing cover, food, and habitat to a diverse array of marine organisms and significant populations of waterfowl.
Vegetation is a complex expression of environmental factors. In Pacific Rim National Park it is expressed as dense, multi-storied, uneven-aged foreshore communities and rich shore zones. Recognizing an understanding the communities making up this vegetative mosaic provide an appreciation for its uniqueness and guidance for its ongoing protection.
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