Critical Areas

Critical areas are habitats that serve important ecolocial linkages and processes in the coral reef community. Coral spawning areas, sea turtle nesting beaches and fish spawning aggregations sites are critical areas that managers must include in the design of an MPA network.
Photos: Left © James Oliver, middle © S. Wear/TNC, right © David Obura

Critical areas are vital to the survival and sustainability of marine habitats. These areas may provide secure and essential sources of larvae, to enhance the replenishment and recovery of reefs damaged by bleaching, hurricanes, or other events. They include high-priority conservation targets, such as fish spawning aggregations and nursery habitats. Fish spawning aggregations are critical in the life cycle of the fishes that use this reproductive strategy. When identifying areas for protection and focusing management activities, it is important to include critical areas in the design of the MPA (or network), to promote healthy ecological systems capable of responding to, and sustaining, different kinds of stress. For more information, see Resilient MPA Design and Critical Areas of the Coral Reef module of this toolkit.

Ecological Linkages

Include Resilient Communities in MPA Design

To design and manage MPAs specifically to survive climate-related mass bleaching and mortality, managers should identify coral reef communities with a high probability of resistance to mass bleaching; afford them high levels of protection; and incorporate these into larger management areas that include as diverse an array of reef types and habitats as possible.

Resilient coral communities, along with adjacent linked habitats, which exhibit low resistance but are also identified by rapid recovery through regeneration or strong recruitment, should be considered for zoning as strict reserves under high levels of management. This will enable control of all direct and upstream sources of threat on these critical areas.

Marine communities are highly interdependent on a variety of habitats and ecological processes, so it is important that a holistic approach is taken to both MPA design and management. Making sure to include all habitats important to the diverse life histories of reef organisms is fundamental. Such habitats include foraging grounds, breeding grounds, nursery areas, and migration routes. It is also important to provide special protections to FSAs, and other areas, known to be sources of larvae for other areas (i.e., source populations). If these areas are poorly managed, areas far beyond the site are likely to be affected, as their source of larvae will be compromised, along with the ability to recover from disturbance.

Ecological Processes

In addition to representative habitats, protection of ecological processes, such as herbivory and predation, should be a high priority for managers. Recent research has shown that presence of large herbivorous fish (e.g., some species of parrotfish) plays an important role in a coral’s ability to recover after a major die-off or disturbance. Recent studies have also demonstrated the importance of predator populations in maintaining healthy herbivore populations, making the case for preserving the trophic structure of a particular site or reef community. Protecting areas that serve as important habitats to herbivores and predators (i.e., critical areas) should be a priority.

Resistant and Resilient Communities

In the face of large-scale, climate-related events, the survival prospects of coral reef communities (e.g., as indicated by their resistance and resilience to mass bleaching) should receive substantial consideration in selection and design of MPAs. Areas that survive stressful events (e.g., mass bleaching), should be priorities for inclusion in a management framework. Communities that have large, old coral colonies (i.e., demonstrating ability to withstand disturbances over time), and those that demonstrate successful recruitment, are also good candidates for focused management.

Resources

R2 Training Manual Module 3 — Principles and Components of Resilience (download pdf, 333k)