Green gravel is a novel technique for restoring kelp forests. It involves seeding small rocks with kelp propagules, rearing them in the lab and then out-planting them into the field.
The juvenile kelps overgrow the green gravel and attach to the underlying reef.
This technique is cheap, simple, and does not require scuba diving, highly trained field workers, or engineered structures. The gravel can be scattering from a boat and can be up-scaled to treat large areas. As a result, it overcomes some of the major hurdles in kelp restoration and provides a promising new defence to combat declining kelp forests.
Green gravel also represents an exciting avenue to ‘future proof’ restoration efforts. By seeding gravel with resilient species or assemblages, we may be able to enhance the resilience of kelp forests to future disturbance or climate change.