Wetland Revegetation in an Agriculturally Degraded Western Red Cedar (Thuja plicata) Forest on Galiano Island, B.C.

Abstract

Cedars for the Next Century is a three-year, three-phase wetland restoration project led by the
Galiano Conservancy Association (GCA). The project goal is to restore the hydrological regime and
native species composition of the historical Western red cedar (Thuja plicata) swamp ecosystem in
the East Branch of the Chrystal Creek watershed, located at the Millard Learning Centre on Galiano
Island. Prior to restoration, the site contained ditches, an agricultural field, and a secondary growth
Western red cedar forest. Due to long-term land use, the East Branch severely lacked productive
soils, hydrophilic vegetation, and surface water sequestration. As part of Phase 2 of Cedars for the
Next Century, GCA planned a full hydrological restoration for the East Branch, including culvert
installation, stream and wetland creation, and native species planting. To achieve biodiversity
objectives, GCA required a revegetation strategy targeting riparian species typical to cedar-swamp
ecosystems. This strategy was co-developed with GCA and included an inventory of existing plants,
a Terrestrial Ecosystem Map (TEM), and Indicator Species Group (ISG) analysis. The TEM identified
three site series in the East Branch, 05 Cw-Bg, 06 Cw-Fd and 11 Cw-Skunk Cabbage, and the ISG
analysis informed the selection of moisture-tolerant native species for planting. To prepare the East
Branch for revegetation, the GCA team applied “rough and loose” mechanical decompaction to
restore topographical complexity and create new wetlands, around which 33 species (1298 total
plants) were planted in November 2022. Fencing, cages, and burlap were used to mitigate invasive
species encroachment and hyper-abundant black tail deer (Odocoileus hemionus) browsing.
Recommendations include monitoring for plant success and Western red cedar regeneration to
inform plant selection for the Phase 3 site in 2023.