Gulf of Alaska | Ecosystem Perspectives MASTER’S POSTER PRESENTATION Direct cascading effects of sea star wasting on rocky intertidal communities Presenter: Mack Hughes , mjhughes4@alaska.edu
Brenda Konar , bhkonar@alaska.edu, University of Alaska Fairbanks Katrin Iken , kbiken@alaska.edu, University of Alaska - Fairbanks
Nearshore communities are often structured by top-down control, such as predation. This control can be disrupted by major events such as the recent Sea Star Wasting (SSW) epidemic that resulted in a large reduction in sea star abundance and diversity along much of the Eastern Pacific coastline, including the Gulf of Alaska (GoA). Here, sea stars are a top predator and differences in community structure post SSW have been observed but the direct cascading effects through trophic levels have yet to be elucidated. The goal of my project is to determine the direct cascading effects that SSW has had on rocky intertidal communities across the GoA, testing the hypotheses: H1) the onset of SSW correlated with increases in sea star prey, namely the gastropod-predator Nucella spp . and the chiton-grazer Katharina tunicata , and H2) increased Nucella predation and Katharina grazing due to release of top-down control correlates with decreases in their prey densities and cover (i.e., barnacles and mussels for Nucella and macroalgae for Katharina ). I am investigating this by using a retrospective analysis on a long-term monitoring dataset (Gulf Watch Alaska from 2006-2021), conducting feeding preference experiments. My research will further our understanding of the extent of top-down control within the GoA’s rocky intertidal ecosystems. This understanding will help contribute to a growing body of knowledge to better understand the cascading effects of large-scale disturbances on top-down controlled ecosystems. I am producing research that will be publicly accessible and disseminated so that it can inform others of relationships within these ecosystems.
Alaska Marine Science Symposium 2023 165
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