Date of Graduation
Master of Science in Environmental Management (MSEM)
College of Arts and Sciences
Northern California’s coastal marine ecosystems support one of the most productive and biodiverse habitats on the planet. Bull kelp forests (Nereocystic lutkeana) form habitats for an abundance of marine mammals, sea bird, fish, and invertebrates. In recent years, compounding ecological and climatic factors have disrupted the balance of the bull kelp forests and led to an unprecedented loss of bull kelp biomass and canopy cover. These areas that are typically teeming with marine life have shifted into a stable state of sea urchin barrens due to over grazing of bull kelp by purple sea urchins (Strongylocentrotus pupuratus). These sea urchin barrens provide very little habitat diversity and do not support the variety of life that rely on habitat forming bull kelp for nourishment, shelter, and breeding grounds. Marine heatwaves and warming ocean trends have exacerbated the detrimental effects of the sea urchins by leaving bull kelp more susceptible to grazing pressures. Estimates have shown a 93% loss of bull kelp canopy cover along the Mendocino and Sonoma counties coastline. This devastation has far reaching repercussions, from multi-million-dollar economic impacts on recreational and commercial fisheries that rely on bull kelp to provide habitat and food to their target species, to the loss of carbon sequestration services. This paper examines kelp restoration case studies to determine which restoration techniques and management practices have been successful. Based on this synthesis, I provide recommendations to the Greater Farallones National Marine Sanctuary (GFNMS) to restore and manage these areas that have been heavily affected by bull kelp loss. My bull kelp restoration and management recommendations for GFNMS are three pronged. 1) Mobilize stakeholders to participate in mass urchin culling events in urchin barren areas that are in close proximity with remaining bull kelp forests. 2) At sites where sea urchins are successfully thinned to a manageable density, employ kelp enhancement techniques of outplanting thermally tolerant juvenile bull kelp and transplanting adult bull kelp from neighboring bull kelp forests. 3) Implement a citizen science and education program to increase awareness and visibility of the collapse of bull kelp forests on the Northern California coast.
Johnson, Olivia, "Bull Kelp (Nereocystic lutkeana) Restoration and Management in Northern California" (2020). Master's Projects and Capstones. 1035.
Marine Biology Commons, Natural Resources and Conservation Commons, Natural Resources Management and Policy Commons, Other Environmental Sciences Commons, Other Plant Sciences Commons, Sustainability Commons, Terrestrial and Aquatic Ecology Commons