PROJECT HIGHLIGHT
This project will conduct two studies to evaluate a novel approach to restoring kelp and to identify the best environmental and ecological conditions for kelp restoration.
PROJECT SUMMARY
Kelp forests support very high levels of biodiversity and form the foundation for many important services including commercial and recreational fisheries, mariculture, recreation/tourism and Indigenous uses. Yet, kelp forests in northern and central California are in crisis, with over 90% of the state's northern kelp forests and additional large expanses of kelp along the central coast lost in recent years.
This collaborative project involving six institutions conducts two complementary studies to address this crisis. In the first study, commercial and recreational divers clear kelp grazers, such as red and purple urchins and the wavy turban snail, separately and in combination, along the perimeter of remnant kelp forests to investigate how this might help kelp forests recover and expand. This study also evaluates how often such clearing efforts need to be repeated and at what financial cost and diver effort. The second study investigates the range of water temperatures, locations and methods best suited to ensure restoration success — for example, if it is more effective to outplant new kelp or remove kelp grazers so existing kelp can proliferate.
In its first year of implementation, researchers have established experimental plots at multiple sites along the California coast to test this "protect and expand" approach. Teams at the University of California, Santa Cruz conducted nine sets of experimental plots in Monterey, while researchers at Sonoma State University established five sets in Sonoma County at Timber Cove and Sea Ranch locations. The experiments target the margins between urchin barrens and remaining kelp forests, with various removal treatments including sea urchin-only and all-herbivore removal plots. Alongside active intervention experiments, researchers are characterizing conditions associated with natural kelp recovery through 11 recovery survey blocks established by the Monterey Bay Aquarium in collaboration with the University of California, Santa Cruz. Environmental data including temperature, wave intensity and freshwater inputs are being collected to generate predictive models for identifying potential areas of natural recovery and optimal locations for future restoration efforts. The project is also tracking costs associated with different restoration approaches and comparing the effectiveness of human removals with natural sea otter predation. The lessons learned from this project will help to protect remnant kelp forests and expand kelp forest footprints, providing guidance for future restoration efforts regarding the timing, location and methods that will promote a higher likelihood of success.
Brent Hughes