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Sea Cliff Shoreline

  Ainslie Point, South Pender Island        

Trincomali, North Pender Island

Sea Cliff W Aerial Cliff View


Description

Sea cliffs are hard, mostly bedrock shores with slopes steeper than 20%. This type of shoreline is common on the Gulf Islands. Backshore soils tend to be shallow and rocky, making them prone to drought.

The sea cliff shore type is 26% of the total shoreline in the Islands Trust area based on the twelve major islands that had shoreline mapping completed.  Gambier Island has the most at 54%, while Denman Island has the least at 3%.   18% of South Pender Island's shoreline has been mapped as the sea cliff shore type.

Physical Features

Sea cliffs are resistant to erosion and tend to be stable over a human time scale.  Sediment transport rates along shoreline nearby sea cliffs are low, because of the limited sediment they supply to the nearshore.  Sea cliffs may also have associated rock fall hazards.

Biological Features

Sea cliffs in the Gulf Islands support the common upper intertidal zone community of barnacles, rockweed and blue mussels, at all wave exposures. Associated species include limpets, periwinkles, shore crabs, and sea stars.  

In areas of higher wave exposure, sea cliffs can have a diverse community of attached algae and invertebrates, in particular in the lower intertidal zone, where lush benthic kelps, red algae and many invertebrate species are found. Bull kelp, a highly productive habitat, occurs throughout the Gulf Islands in nearshore rocky areas, often at rocky headlands like sea cliffs or areas of higher tidal currents.  

Many offshore rock islets in the Gulf Islands are sea cliff shoreline type and are important nesting and roosting areas for sea birds such as Pelagic Cormorant, Black Oystercatcher and Pigeon Guillemot.

Seacliff WEB

 

Page last updated: 01/10/15
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