Restoring Blue Forests with Green Gravel
Green gravel involves seeding small rocks (gravel) with kelp and rearing in the laboratory, then out-planting to the field. The out-planted kelp has high survival and growth
over 9 months, even when dropped from the surface. The kelp eventually over-grew the gravel and attached to the turf substrate.
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’. Marine restoration is challenged by the difficulties involved in working underwater, complex species life histories and large scales of loss. Donor plants must be kept in situ in wave-exposed habitats long enough for reproduction to occur.
This involves complex engineered structures to be attached to the substrate underwater which are often rapidly removed by storms and waves. Deployment of such structures is labour and skill intensive, typically involving scuba diving under challenging and demanding conditions. Such challenges have limited the application, scale and success of marine restoration, particularly for marine forests.
Global active interventions, such as restoration, will be required to restore 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 on a global scale, with a variety of kelp species, and deployable by community groups, tertiary institutions and conservation organisations alike.