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UBC Theses and Dissertations

Zostera marina and Neotrypaea californiensis as indicators of ecosystem integrity in Grice Bay, British Columbia Carty, Sarah Elizabeth


Using indicator species as proxies to assess ecosystem integrity has been identified as a necessary means to develop efficient and effective ways to monitor natural ecosystems. Criteria have been developed to aid in the choice of an indicator species and while there are still limitations, improvements can be made by choosing more than one species and having multiple indices to measure. This study established baseline data on the seagrass, Zostera marina and ghost shrimp, Neotrypaea californiensis for their use as health indicators in Grice Bay, Clayoquot Sound, British Columbia. The widespread distribution and ecological importance of seagrasses and their sensitivity to water quality parameters have led to the use of these plants as biological indicators of water quality. In this study, seagrass biomass, density, size structure, reproductive timing & frequency were quantified as indicator parameters. Physiological indices, for use as early warning signals, were also quantified including sugar & chlorophyll concentrations. Ghost shrimp have not previously been used as an indicator species, however their important role in the food web of Grice Bay as the primary detritivore and as a prey species for juvenile gray whales makes them an important organism to monitor. Indicator qualities of ghost shrimp are those sensitive to water quality, such as density, biomass, population size structure, frequency of reproductive females, size of reproductive females and length of reproductive season.

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