coastal bluff 1  220x136  hhWhat are coastal bluffs?

Coastal bluffs are bedrock outcrops, rocky islets and steep cliffs (often composed of either rock or unconsolidated glacial till), that are located close to the ocean. They form a transition between marine shorelines and forests such as coastal douglas-fir and coastal western hemlock ecosystems. Coastal bluffs are characterized by little or no soil, and the soil that is present is usually low in nutrients. Small differences in soil, moisture and sun exposure in these ecosystems provide opportunities for different types of organisms. For example, rainwater and soil tend to collect in rock crevices, allowing plants to grow there. Coastal bluffs are often exposed to harsh weather, in the form of wind, sea spray, and drought. The plants and animals that live here are adapted to these extreme conditions; nevertheless, they can easily be damaged by trampling and compaction.

What lives on coastal bluffs?

The vegetation on coastal bluffs varies depending on the site. Some common species include:
  • lichens such as sea tar lichen and coastal reindeer lichen
  • grasses such as barren fescue (Vulpia bromoides) and early hairgrass (Aira praecos)
  • shrubs such as Nootka rose (Rosa nutkana), hairy manzanita (Arctostaphylos columbiana) and oceanspray (Holodiscus discolor)
  • herbaceous flowering plants such as nodding onion (Allium cernuum), stonecrop (Sedum spp.), western buttercup (Ranunculus occidentalis), coastal strawberry (Fragaria chiloensis), cinquefoil (Potentilla spp.), sea blush (Plectritis congesta) and shootingstar (Dodecatheon spp.)
Coastal bluffs provide prime nesting sites for birds such as oystercatchers, turkey vultures, cormorants, kingfishers and swallows. Sea lions and harbour seals often use rocky outcrops as haul-outs and for breeding.

Why are coastal bluffs important?

Coastal bluffs are very small components of the landscape, compared with other types of ecosystems, yet they host many rare and endangered plant and animal species. Therefore, they contribute significantly to the biodiversity of British Columbia and southern Vancouver Island. As part of the scenic coastlines we enjoy, they also provide aesthetic and recreational opportunities. Rocky outcrops are the most stable type of shoreline and are often chosen as sites for building houses and other structures. Bluffs composed of glacial till, on the other hand, are unstable, and are subject to erosion. However, they provide a source of fine sediment that is continuously worn away and transported to nearby shores and beaches through coastal sediment processes. This sediment supply is important for maintaining beaches and sand and gravel shorelines.

What threatens coastal bluffs?

Coastal bluffs are susceptible to trampling and compaction from pedestrians, horses, mountain and dirt bikes and other vehicles. Because the vegetation is often shallowly rooted in poor soil, it can be easily disturbed. Nesting birds can also be disturbed by too much traffic, and sometimes abandon their nests or young if they feel threatened by human presence.

Since people are attracted by beautiful ocean views, coastal bluffs are popular locations for residential and commercial development. While bedrock outcrops are relatively stable places to build, bluffs composed of glacial till are very prone to erosion, and any buildings on such slopes should be set well back from the edge. Even in the case of rocky shorelines, steps can be taken to ensure a minimal impact on coastal bluff ecosystems. As with most other ecosystems, invasive species threaten coastal bluffs. One of the more common invaders in these areas is Scotch broom.

How can I help protect coastal bluffs?

For more information on protecting coastal bluffs, please visit our How Can I Help section.

© Image courtesy of Emily Norton

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