Date of Graduation

Spring 5-16-2025

Document Access

Project/Capstone - Global access

Degree Name

Master of Science in Environmental Management (MSEM)

College/School

College of Arts and Sciences

Department/Program

Environmental Management

First Advisor

Simon Scarpetta

Second Advisor

John Callaway

Third Advisor

April Randle

Abstract

California’s kelp forests are some of the most biodiverse and productive ecosystems on the planet. Centuries of anthropogenic degradation via habitat destruction and climate change have culminated in decreased kelp forest habitat at an accelerated rate since at least the 1850s (Scarborough et al. 2022; Rogers-Bennett & Catton, 2019; Kumagai et al. 2024; Smith et al. 2023). This study synthesizes major threats, past and present, to California’s kelp forests, including the overharvesting of multiple species, pollution from coastal development, and climate change impacts. I also examine current management practices regarding kelp forests such as the use of marine protected areas as well as completed and ongoing kelp restoration projects throughout California. Of 83 kelp restoration projects analyzed in California, 71 restoration projects focused on giant kelp, 3 of which are ongoing, and 12 restoration projects focused on bull kelp, 10 of which are ongoing. The most successful projects used multiple restoration methods, with the most successful combination of restoration methods being grazer control, seeding, and transplantation, which yielded successful restoration outcomes in 9 out of 12 projects in California. The least successful restoration method was artificial reefs, which failed in 8 of 16 projects used as the sole restoration method and failed in 12 out of 20 projects when considering restoration attempts that used other kelp restoration methods. The five largest kelp restoration projects used different kelp restoration methods, but all had significant financial capabilities and interest in the restoration activities. These five projects highlight the important role in funding to increase the scale of kelp restoration, the need for diverse resources, the important role of continuous ecological monitoring, and potential to adapt restoration methods to increase the potential for successful kelp restoration. Although California has had over 80 restoration projects, the majority remain small in scale, with the median area of giant kelp restoration projects being 0.51ha and the median area of bull kelp restoration projects being 2.0ha. Multiple individuals involved in kelp restoration cite barriers in policy and long waiting times to obtain proper permitting from the California Department of Fish and Wildlife (CDFW) for kelp restoration and associated activities, citing “blue tape” and highlighting the difficulty experienced by citizen scientists and academics wanting to restore California’s kelp forests. To improve restoration outcomes, I recommend using multiple methods together, such as grazer control, seeding, and transplanting, reintroducing the sunflower sea star to Central and Northern California, increasing the publicity of community-based restoration opportunities, and applying methods from the kelp-harvesting industry to increase the scale of kelp restoration.

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