Abstract
The tidal marshes of the Fraser River Estuary (FRE) support many at-risk native species and ecosystem services. Many of these tidal marshes have been degraded and lost due to urban development resulting in coastal squeeze. The Department of Fisheries and Oceans (DFO) adopted the 'No Net Loss' principle in 1986 to specifically address the loss of fish habitat due to development. One of the ways this principle was applied was through the creation of compensation marshes. Compensation marshes were created between 1986 and 2013 when a proposed development activity would disrupt the productivity of pre-existing marsh habitat and an alternate development site was not feasible. When this occurred, the compensatory action of a replacement marsh of double the area of the impacted existing marsh was planned for. There have been over 100 compensation marshes created in the FRE. Common stressors to compensation marshes consist of wave action from boats, invasive plant invasion, and extensive grazing pressure from Canada geese (CAGO; Branta canadensis). To combat these impacts, some common treatments for these sites involve planting native marsh species, installing log booms to attenuate wave action, and creating goose exclosures. This project focuses on the New Westminster Quay Compensation Marsh (NWQCM) which was established in 1990. NWQCM previously had a shear boom installed along the South edge of the marsh to attenuate waves and protect woody debris from entering the site, but one of the anchor points has since broken, and no longer provides these functions. This has resulted in an accumulation of woody debris on the site, which in combination with the partially-anchored shear boom scour marsh sediment. Sediment scour further leads to invasive plant establishment such as purple loosestrife, yellow flag iris, and reed canary grass which have all been observed on site. The combination of these stressors further constrains establishment efforts of native marsh plants. The two goals of this restoration plan are 1) to study how CAGO use compensation marshes in the FRE and 2) to restore native plant species to the NWQCM to increase plant cover and encourage sedimentation in the marsh. Our study consists of conducting scan surveys at 11 compensation marshes and recording CAGO grazing behaviour. Key findings from our study suggest that CAGO do not heavily use compensation marshes during the fall and winter months, potentially due to lack of grazing viability and seasonality of grazing behaviour. The highest average count of CAGO was in October, and none were observed in November and December. The key objectives of Goal 2 are to increase native plant cover, protect against erosion, and reduce impacts from wake action and LWD accumulation. We propose constructing bio-engineered control structures composed of willow fascines and wattle fences to achieve these objectives.