Need for Restoration
Anthropogenic impacts are often chronic (long-term). Even when they are acute, such as ship-groundings, they can cause physical damage that compromises natural recovery processes.
Where there are chronic human impacts, in order to allow natural recovery processes to operate, passive or indirect restoration measures such as sewage treatment, watershed management, or fisheries enforcement may be needed, followed by active or direct restoration interventions such as coral transplantation or substrate stabilization to assist. Where recovery is impeded because of physical damage, active physical restoration may be a pre-requisite for recovery. It is mainly in situations in which humans impact reefs that restoration (passive or active) is needed. The main socioeconomic purpose for restoring reefs is to return the flow of goods and services provided by healthy reefs to the people who depend on them.
Conditions that drive the need for restoration and the questions that should be considered in order to identify the type of restoration necessary or possible are shown in the table below.
| Conditions driving the need for restoration | Questions which help define restoration approach |
| Reductions in habitat and species diversity, and in habitat size and heterogeneity | What is expected of a natural habitat and what are the natural ecosystem goods and services? Can these be quantified and replaced? |
| Reduction in the population size, dynamics or range of many species | What are the human uses and demands on the system and are these compatible with natural ecological structures and functions? |
| Fragmentation of habitats, increasing the vulnerability of remaining isolated pockets to natural or human-induced environmental changes, especially if fragmentation prevents the movement of propagules | Can the stressors be stopped, mitigated or compensated? If so, will the system recover on its own or require some degree of intervention? |
| Reduction in the ability of naturally functioning ecosystems to provide economically important goods | Are there some human impacts which are unavoidable? What are the human impacts against a background of natural and wider changes, such as global climate change? |
Common reasons for carrying out reef restoration interventions include:
- Lack of awareness in a local community, or a poor appreciation of the economic and cultural value of reef ecosystems
- Loss of biodiversity
- Loss of productivity (food species)
- Loss of key reef components (usually coral, but also adjacent seagrass or mangroves) due to natural disturbances (bleaching, storm damage, coral predation and disease)
- Loss of key ecosystem processes (e.g., recruitment of juvenile corals, grazing of macroalgae by herbivorous fish or urchins) and services.
- Provision of alternative livelihoods (e.g., culture of aquarium products, tourism) for stakeholders who agree to stop harvesting reef resources
- Mitigation for developments that will adversely impact coral reef species at a site, especially the relocation of threatened corals