What are the benefits of assisted versus natural recovery? Development of a decision making framework.
Abstract
Marine assisted recovery options focussed on species are expensive and labour intensive. For most marine species, these barriers, coupled with low levels of economic return mean that no options have been developed to assist recovery. It is therefore likely that for most habitats removal of pressures to support the recovery of degraded habitats and management and conservation of remaining habitats will be prioritised over assisted recovery. Given the low feasibility, high costs and resources required for available assisted recovery options, it is likely these would only be considered where pressures have been removed but populations of high-value species are unlikely to recover naturally due to loss of connectivity and changes in habitat conditions (for example, negative feedbacks). Assisted recovery approaches have clear value for restoring biogenic habitats that have undergone historic declines and which have not recovered naturally and that on their recovered state provide high levels of ecosystem services and goods and benefits. Significant barriers remain to assisting recovery including costs, feasibility, the complexity of projects and the level of resources required. However, approaches are being developed such as the hessian bag planting method for seagrass seeds and the green gravel approach for kelps, that are lower in cost and scalable to larger areas.