Debora Obrist

Degrees: BSc, University of Victoria

Current Position: Master’s student

Email: dobrist@sfu.ca

The Hakai Institute’s 100 Islands Project was launched to explore how marine subsidies impact terrestrial ecosystems on islands across the central coast of British Columbia. The goal of this project is to investigate how the biogeographical features of islands affect their abilities to accept and retain subsidies, shaping the ecologies of plants, beach-cast seaweeds, invertebrates, mammals, and songbirds.

For my master’s project, I am working on the bird component. I am analyzing how physical features of islands, such as area, perimeter to area ratios, topography, and isolation can be predictors of terrestrial songbird species diversity. I am also going to look at how bird diversity is affected by input of marine-derived nutrients on these islands. Lastly, I will study the movement of nutrients from the sea to the birds. Some birds feed directly on marine invertebrates, some eat terrestrial invertebrates that have fed on sea wrack, and others eat seeds or berries of subsidy-fertilized plants. By matching the isotopic signatures from bird feathers and feces to signatures from plants, insects, and seaweed found on these islands, I will be able to determine the percentage of their diet that is marine-derived, and obtain a better understanding of the ecological pathways that lead to nutrient assimilation in these birds.