Pacific salmon (Oncorhynchus spp.) migrations constitute one of the largest nutrient transfers between freshwater, terrestrial and marine ecosystems within the Pacific Northwest. Research has shown strong trophic linkages between salmon-derived nutrients and freshwater and riparian food webs suggesting salmon can play an important role in the maintenance of coastal ecosystem integrity. To date, studies investigating the significance of this nutrient pulse in downstream depositional zones have been limited. My work focusses on small to medium-sized mesohaline estuaries on the central coast of British Columbia. These systems rely on allochthonous nutrient input and can be exposed to over half of all salmon-derived nutrients within a watershed during spawning events. I am investigating estuarine nutrient pathways and trophic structure in twenty discrete, relatively intact, salmon bearing watersheds on the central coast of British Columbia. Specifically, I am interested in the mechanistic processes that mediate the ecological significance of this marine-derived nutrient pulse such as landscape size, connectivity and habitat structure.
I am comparing stable isotopes and size and condition data of estuarine invertebrates, that span multiple trophic levels, against a comprehensive suite of metrics on landscape size, upstream habitat structure, community composition and salmon escapement. By comparing metrics within and between sites across a natural salmon spawning density gradient, I hope to highlight patterns of retention and absorption within these ecosystems.
