Marine protected areas are designated mostly for the purpose of protecting coastal and marine resources from human-induced impacts. Nonetheless, natural events can cause just as great, or greater, disturbances to an MPA ecosystem in a day or week than most human activities can. The worldís coasts are subject to a wide variety of severe natural hazards -- hurricanes, cyclones, tsunamis -- and MPAs are not immune from their impact. Natural climate variability, too, can cause significant shifts in species distribution, with die-outs of coral and other organisms.
These natural phenomena are inarguably a part of the ecosystems that MPAs are designed to protect, yet they can abruptly alter those very ecosystems and create real challenges for managers.
In light of the recent impact of Hurricane Lenny on the Soufrière Marine Management Area on St. Lucia (see next article), MPA News surveyed several experts for their thoughts on the role of natural hazard events and climate variability in MPAs. We also asked how managers could prepare for them.
Role of Natural Events
Natural hazard events are integral to the continual re-formation of coastal ecosystems. Alastair Harborne, marine science coordinator for UK-based Coral Cay Conservation, called the effect of such events on coral reefs inevitable.
"In tropical marine ecosystems, research is unequivocal on the importance of hurricane effects as factors that shape reef communities," said Harborne. "Long-term quantitative monitoring programs have documented dramatic changes in many taxa, including corals and algae, following storm events. Indeed, it seems likely that such disturbances maintain the diversity of reefs by providing opportunities for pioneers and poorer competitors."
Such opportunities may also come as a result of climate variability. Janne Kaje, a research associate with the Joint Institute for the Study of Oceans and Atmosphere (JISAO) at the University of Washington (US), said that extreme seasonal to interannual climate events -- strong El Niño events, for example -- produce adverse conditions for some species while offering brief windows of opportunity to others. "[These events] are akin to natural hazards -- like hurricanes and typhoons -- in that they represent low-probability, high-impact events with potentially significant consequences for ecosystems," said Kaje, referring to climate variability as a normal, essential component of ecosystems.
Kaje said the impacts of climate variability could take any number of forms, including physical habitat destruction (e.g., soft corals and barrier islands); temperature-driven direct mortality (e.g., coral reefs); range movement or range contraction of organisms (e.g., many schooling pelagic fish); or disruption of "normal" patterns of current-driven dispersal (e.g., for larvae of many benthic invertebrates and demersal fish).
Managing for Change
These natural and unpredictable changes in the physical and chemical environment create a moving target for managers charged with protecting coastal and marine ecosystems, said Cliff Robinson, a marine ecologist with Parks Canada. "Coastal ecosystems are continuously evolving and responding to short- and long-term environmental variability," said Robinson. "The challenge facing managers is to understand how human-use activities will impact the ecological integrity -- the structure and function -- of MPA ecosystems, nested within this background of environmental variability."
Robinson said that managers of Parks Canadaís Marine Conservation Areas need to prepare for such variability by developing adaptive strategies that build on monitoring of key ecological components. "Ultimately science has the lead role of assisting managers in developing an understanding of the dynamics of [MPA] ecosystem structure and function over long and short time scales," he said.
JISAOís Kaje added, "Most importantly, managers should embrace the notion that natural hazards and climate variability are essential organizing properties of living systems. Explicit acknowledgment of variability, beginning at the design stages of MPAs, will promote a precautionary management approach that reflects the expectation of change rather than a myopic one of presumed stability."
Kaje said managers could arrange monitoring efforts in order to learn from natural hazard events. While baseline monitoring could be an ongoing activity, for example, predetermined and intensive monitoring plans could be in place for responding to extreme events. Such responsive monitoring could help determine how ecosystems react to environmental changes.
Proactive monitoring is ongoing in Australia, where managers at the Coral Seas National Nature Reserves are keeping a photographic record (aerial and surface) to help reveal impacts related to major storm events on beach and vegetation, according to Leanne Wilks, Assistant Director of Marine Protected Areas for Environment Australia. Tracking of these impacts is important for the management of bird and turtle nesting sites in the reserves. Wilks added that Environment Australiaís Solitary Islands Marine Park has proposed to undertake an overall park monitoring program that would include monitoring for the effects of ocean warming.
Two of the three offices of the Hawaiian Islands Humpback Whale National Marine Sanctuary (US) lie within a tsunami inundation zone. Superintendent Allen Tom has prepared for potential disasters by creating an evacuation plan for volunteers and staff, and being ready to relay tsunami information to the surrounding community. In terms of minimizing damage to natural resources from hazard events, said Tom, the sanctuary could do such things as set mooring pins and construct breakwaters in areas prone to wave damage. "These are natural events, though," he said, "and Iím not sure it is our job as managers to try and prevent them."
Knowledge of the ecosystemís health is the most important part of preparing for a natural hazard event, said Kerim ben Mustapha, a coral scientist with the Institut National des Sciences et Technologies de la Mer (INSTM) in Tunis, Tunisia. "By understanding the biodiversity of the MPA and the functioning mechanisms of its protected ecosystems, the MPA manager will be able to predict how much a natural event may damage these ecosystems," he said. He added that the creation of buffer areas around MPAs, for the study of ecosystem functions and mechanisms beyond the boundaries of the MPA, were essential to such understanding.
Healthy Ecosystems Are More Resilient
Anthropogenic impacts on MPAs have the effect of decreasing ecosystem resiliency to natural change, said several experts. "The interesting question is the degree to which we have affected the ability of reefs to recover," said Coral Cay Conservationís Harborne. "For example, if there has been damage to areas of reefs which supply coral or fish larvae, this will have a significant effect on re-cruitment to communities recovering from natural events."
Harborne said MPA managers could mitigate the effects of natural hazards by maintaining a healthy ecosystem. "Research is still lacking," he said, "but it seems intuitive that a balanced, stress-free area will recover more quickly and ënaturallyí than an area affected by poor water quality, sedimentation, and over-fishing. Managers cannot change the path of hurricanes, but if their [MPA] is in good health and part of a network linked by larval recruitment, then they have a much better chance of long-term success."
Creating more and bigger MPAs, and linking them, might also offer greater resilience from natureís hazards. Said JISAOís Kaje, "A sufficiently large and diverse network of MPAs can provide protection for essential ecosystem components and processes that will buffer species and communities against extreme events and [climate] shifts."
Added Hawaiiís Tom, "[Larger MPAs] would be good for the habitatís and ecosystemís sake as well."
For more information:
Alastair Harborne, Coral Cay Conservation, 154 Clapham Park Road, London, SW4 7DE, UK. Tel: +44-(0)171-498-6248; E-mail: arh [at] coralcay.org; WWW: www.coralcay.org.
Janne Kaje, University of Washington, Box 354235, JISAO/SMA Climate Impacts Group, 4909 25th Ave. N.E., Seattle, WA 98195, USA. Tel: +1 206 616 5349; E-mail: jkaje [at] u.washington.edu.
Cliff Robinson, Ecosystem Services, Parks Canada Agency, 300 - 300 West Georgia St., Vancouver, BC V6B 6B4, Canada. Tel: +1 604 666 2374; E-mail: cliff_robinson [at] pch.gc.ca.
Leanne Wilks, Marine Group, Environment Australia, GPO Box 787, Canberra ACT 2601, Australia. Tel: +61 2 6274 1767; E-mail: Leanne.Wilks [at] ea.gov.au.
Allen Tom, Hawaiian Islands Humpback Whale NMS, 726 South Kihei Road, Kihei, HI 96753, USA. Tel: +1 808 879 2818; E-mail: allen.tom [at] noaa.gov.
Kerim ben Mustapha, Institut National des Sciences et Technologies de la Mer (INSTM), 2025 Salammbô, Tunis, Tunisia. Tel: +216 1 730 420; Fax: +216 1 732 622; E-mail: karim.benmustapha [at] instm.rnrt.tn.