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 or move off 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.
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.
There is urgent need for novel solutions to combat habitat loss in marine ecosystems and promote their resilience to climate change. Kelp forests are highly productive underwater seascapes dominated by large brown seaweeds.
There has been an accelerating loss of these valuable ‘blue forests’ and replacement by turf reefs or overgrazed sea urchin barrens. Marine restoration is challenged by the difficulties involved in working underwater, complex species life histories and large scales of loss. We need upscalable and easy to deploy techniques for to bring back marine forests.
Large-scale active interventions, such as restoration, will be required to protect our kelp forests.
Green gravel is a restoration tool that overcomes some of the major hurdles in kelp restoration and provides a promising new defence to combat declining kelp forests.
Healthy kelp forests that are resilient to future stress maintaining the valuable ecological services and habitats that the forests naturally provide.
We aim for Green Gravel to be an accessible part of the global restoration tool-kit, readily available to those wanting to contribute to the restoration of kelp forest ecosystems.
The tool should be adaptable for use with a variety of kelp species, and deployable by community groups, institutions and conservation organisations alike.