Cowichan Estuary Salt Marsh Rehabilitation Project

Mariners Island

Solid cover of large woody debris in different stages of composition preventing growth of marsh vegetation and smothering tidal drainage channels of vital ecological importance

The rehabilitation of the Salt Marsh of Mariners Island had been identified as a priority project resulting from a comprehensive participatory SWOT analysis implemented by CERCA in 2012. Subsequently a funding proposal had been submitted by CERCA to the Department of Fisheries and Oceans and approved.The project rationale is to rehabilitate approximately three hectares of prime salt marsh interspersed with inter-tidal pools and water channels currently covered by a solid layer of logs and large woody debris in different stages of decomposition. Once restored the target area will again provide food and shelter to a wide spectrum of fauna including Chinook, Coho and Chum smolts thriving along the still un-disturbed sections of shoreline, intertidal pools, and side channels of the Cowichan Estuary.The Cowichan Bay salt marshes are of key importance to a large number of over-wintering shorebirds and waterfowl forming part of a registered "Important Bird Area", attracting an increasing number of bird watchers, wildlife photographers and artists, slowly turning into a popular tourist destination with growing importance to the local economy.The planned restoration of Mariners Island will not only benefit wildlife but also, once restored, will significantly enhance the carbon sequestration capacity of this ecosystem which is recognized as one of the most effective carbon sinks of all vegetation types, by far exceeding our boreal forests in terms of carbon sequestration.The project focuses on the removal of logs and woody debris washed up over time onto the marshes located to the south of the Western Forest Mill log pond in the heart of the Cowichan Estuary. Logs and woody debris moved around by tidal changes and storms in the Cowichan Estuary and marshes prevent and disturb the growth of riparian- and marshland vegetation, most visible and pronounced on Mariners Island, the target area of this rehabilitation project. The removal of large woody debris to be processed on the Mill site of Western Forest Products has been preceded by a large woody debris inventory implemented by CERCA in cooperation with Ducks Unlimited in order to establish baselines for future monitoring. The inventory was based on a random sampling design using geo-referenced plots which later will also be used for a vegetation survey to be spearheaded by Cowichan Tribes in cooperation with CERCA, to be repeated over several years to record salt marsh vegetation recovery. The inventory which covered 15 hectares of salt marsh substantiated the presence of approximately 10,000 logs in different stages of decomposition.This project is implemented by CERCA in close cooperation with Western Forest Products, Cowichan Tribes, Ducks Unlimited, Cowichan Estuary Environmental Management Committee, and the Vancouver Island Land Conservation Management Program of the Fish and Wildlife Branch. The expected completion date of the project will be March 31.Dr. Goetz SchuerholzChair CERCA