Initial Planning for Biological Restoration

Reef in Molokini, Hawaii. When planning any restoration, the type of coral community, including coral species and density of colonies, must be evaluated. Photo © Stacey Kilarski

Can previous coral communities be identified?
Once the areas where biological restoration is to be performed have been identified, the type of coral community needs to be assessed. Look for remnant or healthy coral communities surrounding the damaged area. The healthy areas can serve as a reference site which can be used to guide which species to transplant and the suitable density and composition of species. Alternatively, there may be records of the community composition before the degradation occurred.

What is the extent of the areas requiring restoration?
The total area to be restored needs to be measured. The cost of transplantation will be proportional to the area.

Which coral species would be appropriate transplants at sites selected for transplantation?
The common coral species found at the reference site should be selected for the transplantation site to assist natural recovery. Fast growing, branching species (acroporids and pocilloporids) can act as “engineering species” as they quickly generate topographic complexity. Massive and sub-massive species (poritids and favids) are generally slower growing, but are less susceptible to bleaching, disease and predators. A good approach is to transplant a broad cross-section of species with regard to both the reference site and availability of source material.

What density of transplants is appropriate to assist recovery?
The reference site can provide information on the density of coral colonies on a healthy reef in the area. This gives an estimate of how many transplants per unit area to deploy.

Is there a suitable local source of transplants for the selected coral species?
Once the species to transplant are identified and the estimated numbers of transplants needed, the next step is to locate potential sources of transplant material that are near the rehabilitation site.

Is nursery rearing required?
For small-scale transplantations, it may be possible to work directly with fragments from donor colonies. Projects that aim to rehabilitate large areas will likely require nursery-reared transplant material. In a mitigation project where an area of reef is being sacrificed to development of some kind (e.g., harbor dredging, pipeline construction, etc.) there is generally coral material that is being removed from project impact areas and no need for more source coral.