UBC Theses and Dissertations
Life after death : the importance of salmon carcasses to watershed function Watkinson, Stephen
A model of a British Columbia watershed was constructed using the Atnarko River watershed as a case-study. A new routine in the Ecopath with Ecosim suite of software, Ecotrace, was used to track the flow of marine nitrogen, from returning adult salmon, throughout the aquatic, riparian, and forest regions of the watershed. Although there was no local data available regarding the concentration of marine nitrogen in organisms and secondary data had to be used to parameterize the model, results are consistent with values from other study areas that were derived through stable isotope analysis. The objective of this study was not to predict results for a specific model area but rather a test of the methodology to see if it could be applied to a model area where field data is available. In this respect, the study objective was accomplished. Some possible refinements to the methodology and future uses for the Ecotrace routine are suggested, including using the routine to cross validate diet composition data if used in conjunction with stable isotope data. Also, it is quite clear that salmon managers must consider the importance of marine derived nutrients for all streams and manage salmon harvesting accordingly rather than just focus on the commercially important runs of salmon.
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