Marine Reserves

Marine Reserves

MSEL have worked on several aspects of marine reserve design and impacts.

Impacts of marine reserves

We have been fortunate to study the Exuma Cays Land and Sea Park (ECLSP) in the central Bahamas, which is one of the World’s oldest and most effective marine parks. Our research has made a number of points:

1) Increases in parrotfish biomass inside parks can reduce levels of macroalgae, foster greater coral recruitment, and enhance coral recovery.

2) In addition to increasing the biomass of a number of fish groups (which isn’t surprising), marine reserves can also increase the diversity of a number of fish groups.

3) Detecting marine reserve impacts is challenging because of the inherent natural variability in marine ecosystems. By surveying reef systems in the Bahamas at multiple scales, we distinguish genuine marine reserve impacts from potentially misleading effects.

4) Elevated densities of fish predators have prevent the recovery of the sea urchin Diadema inside the ECLSP.

Mumby PJ, Harborne AR (2010) Marine reserves enhance the recovery of corals on Caribbean reefs. PloS One 5: e8657

Harborne AR, Renaud PG, Tyler EHM, Mumby PJ (2009) Reduced density of the herbivorous urchin Diadema antillarum inside a Caribbean marine reserve linked to increased predation pressure by fishes. Coral Reefs 28: 783-791

Harborne AR, Mumby PJ, Kappel CV, Dahlgren CP, Micheli F, Holmes KE, Sanchirico JN, Broad K, Elliott I, Brumbaugh DR (2008) Reserve effects versus natural variation in coral reef communities. Journal of Applied Ecology 45: 1010-1018

Mumby PJ, Harborne AR, Williams J, Cappel CV, Brumbaugh DR, Micheli F, Holmes KE, Dahlgren CP, Paris CB, Blackwell PG (2007) Trophic cascade facilitates coral recruitment in a marine reserve. Proceedings National Academy of Science 104: 8362-8367

Mumby PJ, Dahlgren CP, Harborne AR, Kappel CV, Micheli F, Brumbaugh DR, Holmes KE, Mendes JM, Broad K, Sanchirico JN, Buch K, Box S, Stoffle RW, Gill AB (2006) Fishing, trophic cascades, and the process of grazing on coral reefs. Science 311: 98-101

Design of marine reserves

We have focused on two aspects of marine reserve design. The first is stratifying reserve placement by the type of temperature regime the corals experience. The aim here is to ‘future proof’ networks of reserves for future impacts of climate change. However, there is great uncertainty over the response of corals to climate change so we actually create multiple potential reserve networks for different assumptions about how corals will respond. We find that some locations are always selected regardless of our expectations for the future. In this case, such locations make a good bet for early inclusion. These methods take account of coral physiology, levels of larval dispersal and consider the scope for adaptation.

Mumby PJ, Elliott IA, Eakin CM, Skirving W, Paris CP, Edwards HJ, Enriquez S, Iglesias-Prieto R, Cherubin L, Stevens JR (2010) Reserve design for uncertain responses of coral reefs to climate change. Ecology Letters (in press)

The second approach to reserve design explicitly looks at the connectivity of reef fish among habitats, principally from seagrass beds to mangroves to coral reefs. The aim is to place extra weight on parts of the seascape which are well connected and therefore more likely to facilitate ontogenetic migrations of reef fish. These methods also attempt to translate static fish abundance data into an overall measure of importance for ecosystem processes and services.

Edwards HJ, Elliott IA, Pressey RL, Mumby PJ (2010) Incorporating ontogenetic dispersal, ecological processes, and conservation zoning into reserve design. Biological Conservation 143: 457-470

Beger M, Grantham HS, Pressey RL, Wilson KA, Peterson EL, Dorfman D, Mumby PJ, Lourival R, Brumbaugh DR, Possingham HP (2010) Conservation planning for connectivity across marine, freshwater, and terrestrial realms. Biological Conservation 143: 565-575

Mumby PJ (2006) Connectivity of reef fish between mangroves and coral reefs: algorithms for the design of marine reserves at seascape scales. Biological Conservation 128: 215-222