No Reef is an Island: Integrating Coral Reef Connectivity Data into the Design of Regional-Scale Marine Protected Area Networks

Countries around the world are taking actions to promote coral reef conservation and management. For example, many countries are working to expand protection of coral reef habitat by designating Marine Protected Areas (MPAs), one of the most widely used methods for protecting coral reefs. It has been observed that coral reefs rely heavily on ocean currents that provide new recruits from near and far locations. These connections are known to be a key ecological support system for coral reefs and studies suggest that reef connectivity influences community-level biomass, population persistence, resilience, and species diversity. However, since connectivity is typically not incorporated into regional design processes, studies have shown that MPA networks rarely achieve their full potential. A key challenge in the MPA network design process is to identify the appropriate size, spacing, and location of MPAs to secure sufficient connectivity processes that will maintain a healthy functioning ecosystem.

In this study, larval dispersal was modeled across coral reefs in the Caribbean and Gulf of Mexico to identify important reef connections on a regional scale. A spatially explicit connectivity model was used to model coral population connectivity based on a 30-day maximum larval dispersal period across eight spawning events from 2008-2011. This information was then used in the conservation planning software Marxan to identify coral reef priority areas that meet conservation targets while maintaining important connections between reef populations. The results suggest that 77% of coral reefs in the Caribbean and Gulf of Mexico with a high regional connectivity value are not included in existing MPAs. Researchers quantified and reported larval connectivity data by Exclusive Economic Zones (EZZ) and used the connectivity information in a systematic conservation planning program to design a regional MPA network that includes these important reef connections. The study hopes to promote multilateral cooperation in coral reef protection and management, aiding in disturbance recovery and improving reef resilience by identifying important shared reef connections between marine jurisdictions.

Author: Schill, S.R., G.T. Raber, J.J. Roberts, E.A. Treml, J. Brenner, and P.N. Halpin
Year: 2015
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PLoS ONE. DOI:10.1371/journal.pone.0144199

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Minimizing the Short-Term Impacts of Marine Reserves on Fisheries While Meeting Long-Term Goals for Recovery

No-take marine reserves are often proposed as management tools to recover small-scale fisheries, which, if enforced, can improve mid to long-term harvests and profits. However, the short-term losses may prevent fishers from supporting and implementing no-take reserves, resulting in a loss of recovery of fisheries. Trade-offs between short-term loss in profits and long-term benefits to small-scale fisheries were quantified, using a multispecies model of coral reef fisheries for one case study. Impacts of reserves at different time scales depend on the social and management context, but the key to gaining support for marine reserves is to quantify the trade-offs at different time scales for stakeholders and policy makers. Policies for implementing marine reserves that are flexible can offer options with less short-term losses for fisheries that can be more appealing to fishermen, while still reaping the long-term recovery benefits.

Author: Brown, C.J., S. Abdullah, and P.J. Mumby
Year: 2014
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Conservation Letters 8(3): 180-189

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The Micronesia Challenge: Assessing The Relative Contribution Of Stressors On Coral Reefs To Facilitate Science-To-Management Feedback

The Micronesia Challenge is an international conservation strategy initiated by the political leaders of 6 tropical island nations to conserve at least 30% of marine resources by 2020. Growing population and a shift towards cash-based economies have started to erode the traditional sources of sustainable reef management and have increased pressure upon marine resources. This study examined the effects of human populations on the diversity, function and status of coral reef ecosystems across Micronesia by assessing ecosystem condition to evaluate conservation goals of the Challenge, examining the distribution and variance of ecosystem condition as indicators of ecological stability and looking at the role of two stressors – fishing and pollution – in driving ecosystem metrics. Results showed that fishing pressure was a primary determinant of ecosystem condition across the majority of locations studied. Reef habitats that were most impacted by localized stressors also had the least stable ecosystem condition scores. In conclusion, habitats close to urban centers may require more management effort and may show less of a positive response to management than distant sites. Also, fish assemblages appeared to have a hierarchical influence upon coral-reef ecosystems compared with localized pollution. Prioritizing management upon herbivore size and diversity may best preserve the trophic relationships responsible for ecosystem services that coral reefs provide to the Micronesian island nations.

Author: Houk, P., R. Camacho, S. Johnson, M. McLean, S. Maxin, J. Anson, E. Joseph, O. Nedlic, M. Luckymis, K. Adams, D. Hess, E. Kabua, A. Yaon, E. Buthung, C. Graham, T. Leberer, B. Taylor, and R. van Woesik
Year: 2015
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PLoS ONE 10(6): e0130823/ doi: 10.1371/journal.pone.0130823

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Evaluating The Relative Conservation Value Of Fully And Partially Protected Marine Areas

Marine protected areas (MPAs) offer various states of protection and are often viewed as a conflict between conservation and fishing. This study synthesized research that compared partially protected areas (PPAs), no-take reserves (NTRs) and open access areas (Open), to assess the potential benefits of different levels of protections of fish populations. Response to protection was examined in relation to MPA parameters and the exploitation status of fish. 40 relevant studies were included in the meta-analysis. The results suggested that PPAs significantly enhance density and biomass of fish relative to Open areas. NTRs yielded significantly higher biomass of fish within their boundaries relative to PPAs. The authors conclude that MPAs with partial protection confer advantages, such as enhanced density and biomass of fish, compared to areas with no restrictions. The strongest responses occurred for areas with total exclusion. MPAs with a combination of protection levels are a valuable spatial management tool especially in regions where stopping all activities is not politically and socio-economically viable.

Author: Sciberras, M., S.R. Jenkins, R. Mant, M.J. Kaiser, S.J. Hawkins, and A.S. Pullin
Year: 2015
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Fish and Fisheries 16: 58-77. doi: 10.1111/faf.12044

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Marine Zoning In St. Kitts And Nevis: A Design For Sustainable Management In The Caribbean

This paper details a marine zoning process for the island nation of St. Kitts and Nevis in the Eastern Caribbean, incorporating the use of marine spatial planning (MSP) and marine zoning to address multiple uses in the same ocean space. Multiple uses include coastal protection, food security, tourism amenities, biodiversity protection and climate change adaptation. MSP is an approach facilitating a balanced co-existence between marine sectors with competing interests and attempts to combine marine management strategies by describing the local context, outlining key activities and discusses planning process outcomes. Key activities include engaging stakeholders, establishing clear objectives, building a multi-objective geodatabase, generating tools to assist stakeholders and decision makers consider zoning plan options and using a participatory process to outline zone locations. The paper concludes that this approach helped provide an integrated view of marine space and uses for St. Kitts and Nevis and the stakeholders were able to develop a shared vision for their waters. There were also challenges throughout the MSP process and lessons learned were generated to help improve future marine planning and zoning process.

Author: Agostini, V. N., S.W. Margles, J.K. Knowles, S.R. Schill, R.J. Bovino, and R.J. Blyther
Year: 2015
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Ocean & Coastal Management 104: 1-10. doi:10.1016/j.ocecoaman.2014.11.003

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The Intrinsic Vulnerability To Fishing Of Coral Reef Fishes And Their Differential Recovery In Fishery Closures

Coral reef fisheries play a role in livelihoods and local economies around the world, but the impacts of fishing on targeted species of reef fish is poorly understood. The authors of this study examined the vulnerability of different species of coral reef fish to fisheries and evaluated the effectiveness of no-take reserves and periodically-harvested closures. Using life history traits to characterize the vulnerability of fish species to fishing, they found that larger-bodied carnivorous fish have a higher vulnerability compared to smaller-bodied herbivores and detritivores. In no-take areas, moderately to highly vulnerable species take a significantly longer time (decades) to recover than less vulnerable species. Based on these findings, they make the following recommendations for managers:

    • Expand studies of reef fish to improve estimates of vulnerability; Maintain long-term (20-40 year) no-take areas for full population recovery
    • Enforce compliance of no-take areas
    • Control timing and intensity of periodic closures for long-term fishery benefits
    • Use periodic and closures and no-take areas together as fishery management tools

    Author: Abesamis, R.A., A.L. Green, G.R. Russ, and C.R.L. Jadloc
    Year: 2014
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    Reviews in Fish Biology and Fisheries. doi: 10.1007/s11160-014-9362-x

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Micronesia – Predator Outbreaks

A Well-Developed Community-Based Marine Protected Area Proves Resilient to a Crown-of-Thorns Sea Star Outbreak

Nimpal Channel Marine Conservation Area, Yap, Federated States of Micronesia

The Challenge
Yap State is situated in the westernmost region of the Federated States of Micronesia (FSM). The main island of Yap State is located within the Indo-Pacific center of biodiversity. The island is approximately 100 square kilometers, with a densely vegetated and hilly landscape. It is home to 7400 residents spread over 10 municipalities, a relatively small population compared to the other states of Micronesia. The population and urban center are slowly growing, placing increasing pressure on the islands’ natural resources for subsistence and economic gain.

The Nimpal Channel is located off the central-western coast of Yap. Both Okaw and Kaday villages have their fishing grounds associated with the Nimpal Channel. The villages are within the municipality of Weloy, home to approximately 1000 residents. In 2005, a men’s village meeting was called to address the ongoing problem of overfishing in their channel, and decided to seek help and information from outside their community. In 2006, a rapid ecological assessment (REA) was conducted across Yap Proper, including the Nimpal region, so that stakeholders could get a better sense of the current status of their resources. The coral-reef monitoring and assessment team for the REA process consisted of many knowledgeable fishermen from Okaw and Kaday villages, as well as regional scientists with local and global expertise. Following data collection and reporting efforts, and realizing that Nimpal’s resources were not as well off as many other places in Yap due to both natural causes and local fishing pressures, these two villages began discussing their desire to set aside part of their reefs as no-take fishing areas.

Monitoring seagrass beds. © Nimpal Channel MCA.

Monitoring seagrass beds. © Nimpal Channel MCA.

While the Nimpal Channel is very narrow (approximately 0.5 kilometers in width) and has only a limited mangrove stand associated with it, the two communities proposed to make it a Marine Conservation Area (MCA). Through the REA process, marine scientists recommended areas for protection that were larger, deeper, and had more extensive connections with nearshore mangrove habitats known to nourish juvenile fish populations. To marine scientists, the area that Okaw and Kaday proposed to set aside was clearly influential for the locally-owned marine resources, yet was smaller in size and harbored less biological diversity in comparison to other larger and more extensive channel systems nearby. In short, this was not the most ideal area to bolster fishery resources based upon ecological criteria alone. However, the timing was right, and the two communities strongly supported management in that area. Shortly after, in May 2008, Okaw and Kaday, in partnership, publically declared the Nimpal Channel as a Marine Conservation Area with technical support from the Yap Community Action Program.

Within only 1-2 years, monitoring results began to document improved fishery resources in the conservation area. These positive results were an immediate testament to strong community support for management, and dedicated local enforcement. Four years after formalizing the Nimpal Channel Marine Conservation Area, in 2012, a more formal scientific assessment of the channel reefs highlighted that the reef’s condition is second-highest among other MCAs in the region despite having one of the smallest extents. The MCA exceeded the expectations of many marine scientists and changed the way they thought about establishing new marine protected areas going forward. In this case, strong social acceptance and enforcement was more important than ecological criteria.

A crown-of-thorns starfish on a reef in Yap outside of Nimpal MCA. © Peter Houk

A crown-of-thorns starfish on a reef in Yap outside of Nimpal MCA. © Peter Houk

In late spring 2009, Acanthaster planci, commonly known as the crown-of-thorns sea star (COTS), began populating the coral reefs around Micronesia (from Pohnpei westward to Yap). A. planci is a carnivorous species of starfish that preferentially preys upon hard corals such as Acropora spp. and Montipora spp. A. planci were first quantified in monitoring programs off the southwest coast of Yap, and anecdotal reports from fishermen and data suggested a northward migration up the west coast of the island.

Actions Taken
Healthy coral reef systems with high levels of fishery resources have been shown to be resistant to the threat of an A. planci outbreak based upon recent evidence from places like the Great Barrier Reef and Fiji. While the exact mechanism remains elusive, there appears to be some added resistance to these natural disturbance events from healthy fish populations through predation and/or other biological interactions. Reefs that have already been stressed by increased sedimentation, reefs with low numbers of predators due to overfishing, and reefs with low coral diversity have proven most vulnerable to A. planci predation.

Acropora coral showing feeding scars from crown-of-thorns starfish on a reef outside of Nimpal MCA in Yap. © Peter Houk

Acropora coral showing feeding scars from crown-of-thorns starfish on a reef outside of Nimpal MCA in Yap. © Peter Houk

This outbreak of A. planci was not a new threat for Yap. A. planci outbreaks have been described as natural, cyclical events. There are a few theories on why the outbreaks occur. Some experts theorize that COTS outbreaks occur when the sea stars ‘sense’ oceanic conditions are most conducive for their larval offspring to successfully develop, and hence the initial outbreaks may be triggered by some form of nutrient enrichment in the surface waters near coral reefs. Following spawning from initial population outbreaks, it has also been hypothesized that larvae may get caught in ocean currents and somehow influence secondary starfish outbreaks downstream. In Yap, the single most significant COTS event was documented in the early 1970s, although there is local knowledge of smaller outbreaks over the years.

To the local community, the sea stars are well known, but their lifecycles remain mysterious. Locals understand the origins of threats to the reefs like bleaching, sedimentation, and overfishing; however outbreaks of the crown-of-thorns sea stars just suddenly occur without any obvious proximal cause. During the 2009 A. planci outbreak there was no official attempt on Yap to remove the sea stars from their reefs, but fishermen noted their presence. In the case of the Nimpal MCA, the communities did not choose to remove starfish because of adherence to the established no-take MCA policy.

How Successful Has it Been?
The recovery of the coral reefs to the A. planci outbreak in Yap varied. A recent study revisited the study sites where coral populations were monitored as part of the 2006 REA survey and found interesting results. Many reefs along the western coast of Yap showed an expected decline in coral colony sizes and diversity, yet there was one unique exception. The Nimpal Channel MCA appeared to be more resilient to the disturbance event compared with sites to the north and south of this channel. Remarkably, no sea stars were found in the protected area during surveys shortly after the COTS event. In fact, monitoring of the area during the disturbance revealed an increase in coral colony sizes, no significant change in diversity within coral groups, and consistently high fish biomass. Reefs in the protected area showed high abundances of Porites spp. (the less desired coral for A. planci) but Acropora spp. also remained throughout the disturbance period. The area’s resistance to COTS is hypothesized to be due to an intact predator fish population and high coral diversity.

Community participants in a planning workshop. © Nimpal Channel MCA

Community participants in a planning workshop. © Nimpal Channel MCA

In contrast, formerly diverse reefs with extensive coral growth, such as off the southwestern tip of Yap, had the greatest coral reef damage after the sea star outbreak, with little recovery reported as of 2013. Other coral reefs to the north of the Nimpal Channel MCA started to recover in 2012, but recovery has been a slow process and remains ongoing. These findings suggest that the establishment of the locally-managed MCA may have benefitted the resilience of Nimpal’s reefs, and might be supporting recovery along adjacent reefs.

This case study highlights the importance of well-managed marine protected areas for weathering disturbance events. Nimpal Channel MCA appeared to provide added resistance to the COTS disturbance through a series of highly influential, but still poorly understood, ecological processes.

Installing monitoring equipment. © Nimpal Channel MCA

Installing monitoring equipment. © Nimpal Channel MCA

While the Nimpal Channel MCA was initially established to aid fish stock recovery, it was later found to have added benefits of enhanced resistance to COTS. The success of the Nimpal Channel Marine Conservation Area in both enhancing fish populations and mitigating the damage done by the 2009 disturbance continues to be a very popular and productive discussion at regional management meetings across Micronesia. This example shows that marine protected areas have additional benefits that we are only beginning to understand. Certainly the list of benefits will grow into the future.

Lessons Learned and Recommendations
People, rather than biology and science, are most important to think about when establishing a marine protected area. Without the community’s dedication to protecting their channel, the Nimpal Channel Marine Conservation Area would never have been established. Based on biological considerations and the small size of the managed area, scientists felt other areas were better suited to set aside as a protected area; it was only through the community’s will and support that their protected area was established. Science is used to drive management recommendations, but other factors might be more relevant for successful management.

The success of a marine protected area is dependent on community involvement and knowledge. The success of the Nimpal Channel MCA is due to community-based decisions based in traditional ecological knowledge and supported by scientific measures. Consequently, the Nimpal Channel MCA is one of the few functioning protected areas in Yap.

Quantitative monitoring is essential for responding to increased frequency and intensity of disturbances. Identify critical biological thresholds in your management area. Reef ecosystems are complex systems that can behave in a non-linear manner (for instance, the decline of a predator fish population might not have the effect of reducing a reef’s resistance to an A. planci outbreak until the predator fish population declines past a critical threshold). Part of this non-linear behavior is related to trophic interactions (interactions between predators and prey, for example). Science has not fully explained trophic interactions and thresholds in coral reef systems. Disturbances are becoming more and more frequent; there might be a COTS outbreak one year and a bleaching event the next year. Because of the increasing frequency and severity of threats to coral reefs, it is important to collect quantifiable data to be able to perceive rates of change. For example, monitoring fish biomass in your area can be a good starting point to understanding how fish biomass is related to reef resilience. The relative level of biomass within different trophic levels may be related to the maintenance of coral reefs through time.

Funding Summary and Partners

Kaday Community and Cultural Development Organization
Pacific Marine Resources Institute
Yap Community Action Program
Marine Laboratory, University of Guam
Water and Environmental Resource Institute of the Western Pacific, University of Guam
Palau International Coral Reef Center (PICRC)
The Nature Conservancy Micronesia Program
Micronesian Conservation Trust
Conservation International’s Pacific Islands Program
Pacific Development & Conservation Trust
OneReef Micronesia

Written by: Peter Houk, Marine Laboratory, University of Guam
Berna Gorong, Kaday Community and Cultural Development Organization
Eva Buthung, Yap Community Action Program, Marine Program

This case study was adapted from: Cullman, G. (ed.) 2014. Resilience Sourcebook: Case studies of social-ecological resilience in island systems. Center for Biodiversity and Conservation, American Museum of Natural History, New York, NY.

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Herbivory And The Resilience Of Caribbean Coral Reefs: Knowledge Gaps And Implications For Management

This paper explores herbivory and how it affects the resilience of coral reefs in the Caribbean. The authors identify important knowledge gaps that limit our ability to predict when herbivores are most likely to support resilience. The authors explore:

  • What processes operate to prevent or facilitate coral persistence and recovery, and how are these influenced by herbivory?
  • What are the independent and combined effects of different species of herbivores in limiting algae and facilitating reef-building corals?
  • What factors limit herbivore populations and the process of herbivory on coral reefs?

The impacts of herbivores on coral reef resilience are likely to be highly context- dependent, thus it is necessary to understand the roles that particular types of herbivores play in limiting harmful algae and facilitating corals under a range of environmental conditions to improve sustainable management of coral reef ecosystems.

The paper provides specific information to guide how to manage herbivore populations to facilitate healthy, resilient coral reefs. The authors present the following management recommendations/guidance:

  • Local management efforts should focus on minimizing direct sources of coral mortality, such as sedimentation and pollution, as well as restoring ecological processes, such as herbivory, that are important for coral persistence and recovery
  • Maintaining healthy herbivore populations is likely to mitigate the negative impacts of ocean warming since abundant herbivores can control algae that inhibit coral recovery following coral decline
  • Better spatial management of fishing could minimize trade-offs between the need to maintain high levels of grazing while supporting sustainable fisheries
  • Implementation of marine protected areas or other spatial restrictions on herbivore fishing will only be effective if we can sustainably manage herbivore populations outside of protected areas. Different species of parrotfishes have different life-history traits and different impacts on benthic communities, thus should not be managed as a single species complex
  • Managers will need to ensure that reefs have the right mix of herbivores to carry out the full set of functions normally performed by the herbivore guild
  • It is critical to protect seagrasses and mangroves, which are important nursery habitats for several species of Caribbean herbivores
  • In cases where degradation has been severe and feedbacks are operating that could slow or prevent coral recovery, management actions targeted specifically at breaking feedbacks that maintain reefs in a degraded state are necessary

Author: Adam, T.C., D.E. Burkepile B.I. Ruttenberg, and M.J. Paddack
Year: 2015
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Marine Ecology Progress Series 520:1-20

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