MPA Perspective: Scientific Principles for Marine Reserve Systems

By Bill Ballantine, Leigh Marine Laboratory

Progress in establishing fully-protected marine reserves has been slow and highly variable among regions. Most reserves have been small and isolated, and were created for special reasons that were locally acceptable. However, on a world scale, progress has been continuous and has steadily accelerated. Recently, systems of marine reserves have been discussed, and last year the first two systems were established – in Victoria, Australia and around the Channel Islands, California (MPA News 4:7 and 4:6).

Moving to a consideration of systems – as opposed to individual protected areas – significantly changes almost everything, from science and economics to politics. We need clear scientific principles. In this article, I assume a commitment to systems, and attempt to list the set of scientific principles required. It is encouraging that members of the general public regard most of these principles as common sense. Argument mainly comes from those managers and scientists who find difficulty upgrading their thoughts from the very real problems in establishing single reserves.

1. Systems of fully-protected marine reserves are an addition to standard marine management. Detailed (i.e., problem-solving) and general (i.e., zoning) management will continue to apply and develop in the majority of the sea. Marine reserves are a new and different approach but provide support to standard management, especially in the absence of good data or a full understanding of the ecology.
2. Systems of marine reserves are fully proactive. The aim is to conserve (or restore) the whole range of marine biodiversity and to maintain all the intrinsic ecological processes. While they are likely to reduce some existing problems, this is incidental.
3. Marine reserves have multiple benefits to many sectors of society. All of these derive from the less disturbed (more natural) state, and are optimized by increasing the degree of naturalness.
4. In scientific terms, marine reserves are controls, not manipulations. Despite the viewpoint of politicians, by definition there cannot be an “effect” of the blank, the undisturbed piece. This is not a trivial or semantic point. The reversal of logic in talking about “reserve effects” seriously distorts thinking. When the density of a target species inside a reserve reaches 10 or 20 times that outside, this is often welcomed as a reserve effect, when we should focus on the indication of serious over-fishing outside the reserve (the manipulation effect).
5. Single marine reserves become less disturbed (more natural), but this takes time. Some changes take place quite quickly, but others may take 5, 10, or 20 years.
6. Systems of marine reserves will become even less disturbed, but this takes even longer. While it is clear that reserves are less disturbed (and therefore a sensible baseline), the baseline will shift.
7. Changes within the reserve system will slowly affect the region outside the reserves and produce changes there. These are the reserve effects and are of great interest to fisheries and other resource users.
8. All these changes are essentially unpredictable, although when a particular type has been observed several times, it is probable in similar situations.
9. The shifting baselines and the initial lack of prediction are often regarded as problems, but the situation should be seen as an opportunity for science and management. Analogous problems occur in other branches of science (e.g. physiologists can never precisely define a healthy animal, and keep learning more about what this means). A wide watching brief is needed to notice the changes, but for the first time we will have an objective (and steadily improving) measure of the intrinsic properties of marine habitats and ecosystems.
10. These considerations make the scientific principles for establishment of marine reserve systems relatively clear and straightforward. Systems must be:
    1. Fully-protected (against all reasonably-preventable human disturbances)
    2. Permanent (both the changes and the benefits are accumulative)
    3. Fully representative of all biogeographic regions and of all major habitats within each region.
    4. Spatially replicated for each habitat and ecosystem (to guard against accidents, to increase access to benefits, etc.)
    5. Spread as a network of reserves throughout the region, and spaced so as to promote connection by larval drift.
    6. Of a size which ensures self-sustainability. The separate reserves can aim only for a degree of ecological viability, but the whole system must be sustainable.
11. In any region there will be many possible ways of satisfying these principles. Provided the principles are adopted as policy, this allows existing users and interest groups a useful and proper role in the precise arrangement of the reserves.
12. None of the above points or principles are original, and most have already been adopted in at least some regions for some aspects of reserve establishment. The move to systems, however, makes general acceptance of the basic principles urgent and important.

For more information

W.J. (Bill) Ballantine, Leigh Marine Laboratory, University of Auckland, Box 349, Warkworth, New Zealand. Tel: +64 9 422 6071; E-mail: b.ballantine@auckland.ac.nz; Web: www.marine-reserves.org.nz.