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Hawaii – Coral Disease


Detection of a Coral Disease Outbreak in Kauaʻi, Hawaiʻi and Lessons for the Future

Location
Hanalei, Kauaʻi, Hawaiʻi

The Challenge
Hanalei, on the North Shore of Kauaʻi, Hawaiʻi, is a small community of about 450 permanent residents. The Hanalei region is rich in biodiversity and cultural tradition and is home to species of high conservation value. Five ahupuaʻa, the traditional Hawaiian land division, drain into Hanalei Bay. There are also three culturally important fish ponds, a traditional Hawaiian aquaculture technique that encloses or diverts stream waters into an enclosed near shore area for purposes of rearing fish for local consumption. The Hanalei River is one of fourteen American heritage Rivers in the United States.

Hanalei River and Valley

Hanalei River and Valley. © Hanalei Watershed Hui

Tourism is the main economic driver on Kauaʻi. Many community members operate small-scale tourism businesses. On the North Shore, only about 25% of the residents are long-term, permanent residents; many residential properties have been converted to vacation rentals, with many of these visitors and seasonal residents originating from the mainland United States.

The community is highly engaged in natural resource management and planning and has identified major causes of land-based pollution including the conversion of single family homes to more intense commercial uses, inefficient waste water management systems, natural erosion, over-use of fertilizers, and erosion and disturbance caused by feral pigs. Strong wave action characterizes the ocean waters surrounding Hanalei, ensuring that the water surrounding Hanalei’s reefs are generally well mixed and water residence times are low.

Answering media questions

Answering media questions about the coral disease response.
© Hawaii Division of Aquatic Resources

In 2004, scientists studying the reefs on the North Shore of Kauaʻi first observed a black band coral disease at low levels. Then, in 2012, outbreak levels of the disease were reported to the volunteer reporting network, Eyes of the Reef (EOR). Scientists with the United States Geological Survey (USGS), University of Hawaiʻi Institute of Marine Biology (UH), and the National Ocean and Atmospheric Administration (NOAA) have now confirmed that the disease affects three species of rice corals (Montipora capitata, M. patula, and M. flabellata), and, with some variation across sites, approximately 1-8% of colonies of these species. While these percentages are relatively low, Montipora corals are the dominant reef-building corals on North Shore reefs and therefore the disease has the potential to have a significant impact on reef structure and function. Black band coral disease can move through a coral colony very fast. Typically a disease front of cyanobacteria can be observed. It leaves behind dead coral tissue and algae covers the exposed skeleton.

Actions Taken

black band disease

Documenting the impact of the black band disease. © Hawaii Division of Aquatic Resources

Once the Eyes of the Reef Network confirmed the coral disease outbreak, USGS, UH, and NOAA conducted an initial assessment, according to the established protocol of the Rapid Response Contingency Plan (RRCP). The RRCP provides the Hawaiʻi Division of Aquatic Resources (DAR) and its partners with a plan to respond to events affecting reef health, including coral disease, coral bleaching, and crown-of-thorn starfish (COTS) outbreaks. The first step after receiving the report was getting partner scientists and government biologists to confirm and assess the extent of the disease. In 2012, a UH microbiology laboratory identified a cyanobacteria responsible for the disease, similar to diseases that have been observed in the Caribbean and the Indo-Pacific. A UH doctoral student surveyed Kauaʻi’s reefs in 2013 and confirmed that the disease was predominantly affecting the North Shore (86% of the 21 northern surveyed sites had the disease present, while only one site out of four in the south had the disease). The press covered the disease outbreak extensively, which brought attention and community concern about the issue.

Lesions from black band disease

Lesions from black band disease on a coral (healthy coral is to the left of the disease front, dead coral is to the right). © University of Hawaii Institute of Marine Biology

There is relatively little known about coral diseases and less about how to manage diseased reefs; therefore, research is a major part of the first phase response. DAR partners are currently undertaking studies on diverse topics including disease transmission, potential treatments, the influence of coral health on coral susceptibility to the black band coral disease, how environmental factors correlate to the incidences of black band disease, and an experimental treatment option. This research will provide essential information to more effectively identify management options.

Members of the coral disease laboratory at University of Hawaiʻi Institute of Marine Biology have been piloting an experimental treatment for affected coral colonies. Application of marine epoxy putty to edges of the disease lesions on affected corals has been found to effectively stop or slow disease progression on corals and a larger trial of effectiveness is a next step.

How Successful Has it Been?
In January 2014, DAR formed a Management Response Team with the partners that conducted the initial disease assessment as well as the Environmental Protection Agency (EPA), DAR biologists and education specialists, and a coral specialist from the Kewalo Marine Laboratory. The purpose of the Team, as described in the Rapid Response Contingency Plan, is to review incoming data regarding the disease outbreak, communicate the event to the public, and evaluate management options. Thus far, the team has prioritized projects that will identify environmental drivers for the disease, evaluate potential management strategies, and launched a website where they will continue to post the latest information about the response. The black band disease outbreak is ongoing and no recovery can be reported as of yet.

Lessons Learned and Recommendations
Lessons learned and key recommendations include:

    • A plan facilitates a coordinated response. The existence of the Rapid Response Contingency Plan enabled DAR and its partners to respond to the black band coral disease in an organized manner. Some diseases move quickly and can cover large areas, so it is good to be prepared and to know what resources are available to respond to these events.
summer camp about coral health

DAR staff teaching a local summer camp about coral health. © Hawaii Division of Aquatic Resources

  • Community involvement is key. The citizen science network Eyes of the Reef is able to recognize coral disease outbreaks more quickly than if DAR staff had been working alone. In this case, community members expanded the capacity of managers to monitor for coral disease disturbances and will play a key role in the reef’s recovery.
  • Communication is critical when responding to this type of disturbance. Having a communication plan or involving a communication expert from the beginning would have aided the team in informing all partners and the community on Kauaʻi of what was known about the coral disease and about the research being done.
  • Contingency funding continues to be a substantial barrier. It is difficult because you cannot predict when, where, and how much funding will be needed for a disease event. A finance plan needs to be created that will allow funds to be isolated specifically for coral disease, bleaching, and COTS disturbances.
  • Partnerships are essential. Investigating a coral disease takes a multi-disciplinary team of scientists, managers, NGOs, communication experts, community leaders, private sector participants, etc. Collaboration can allow more resources to be leveraged in a timely and efficient way during a coral disease disturbance. DAR is building on this lesson by establishing the first global learning exchange of managers who respond to these types of coral reef impacts at the September 2014 U.S Coral Reef Task Force Meeting.

 

Funding Summary
Hawaiʻi Department of Land and Natural Resources, Division of Aquatic Resources (DAR) and Division of Boating and Ocean Recreation (DOBOR)The School of Ocean and Earth Science and Technology (SOEST)University of Hawaiʻi Institute of Marine Biology (HIMB)US Geological Survey (USGS)
National Oceanic and Atmospheric Administration Coral Reef Ecosystem Division (NOAA-CRED)Several additional community partners also contributed resources and supplies

Lead Organizations (Management Response Team Members)
Hawai‘i Department of Land and Natural Resources, Division of Aquatic Resources
University of Hawaiʻi Institute of Marine BiologyNational Oceanic and Atmospheric Administration, Pacific Islands Fisheries Science Center, Coral Reef Ecosystem Division
The Environmental Protection Agency, Pacific Island Region
U.S. Geological Survey Wildlife Health Center
University of Hawaiʻi Kewalo Marine Laboratory
University of Hawaiʻi Department of Microbiology

Partners
Bubbles Below
Eyes of the Reef
Hanalei Watershed Hui
Kauaʻi Community College
Seasport Divers
Waipa Foundation

Resources
Reef Response: Black Band Coral Disease On Kauaʻi
Eyes of the Reef Network
Reefology 101, Coral Health and Ecology Forum
Hawaii Coral Reef Strategy, State of Hawaii (pdf)

Written by: Anne Rosinski, Marine Resource Specialist, Division of Aquatic Resources, Hawaiʻi Department of Land & Natural Resources
Makaʻala Kaʻaumoana, Hanalei Watershed Hui

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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U.S. Virgin Islands – Disturbance Response


The U.S. Virgin Islands BleachWatch Program

Location
U.S. Virgin Islands

Bleaching Coral. Photo © TNC

Bleaching Coral. Photo © TNC

The Challenge
In 2005, coral reefs throughout the tropical Atlantic and Caribbean were severely impacted by a mass coral bleaching event triggered by prolonged exposure to above normal water temperatures. The bleaching observed in 2005 caused some direct mortality and was also followed by an increased incidence of disease outbreaks. Multiple studies reported this pathway of bleaching followed by increased incidence of disease, with corals varying in degree of mortality resulting from both stresses. This event caused resource managers to realize a formal plan was needed to better respond to coral bleaching events and communicate with stakeholders.

Actions Taken
The U.S. Virgin Islands (USVI) BleachWatch Program was developed to assess and monitor coral bleaching primarily from warm water events and document the distribution, severity and impacts of bleaching to reefs and reef communities. The program was developed by adopting and modifying strategies from the Great Barrier Reef Marine Park and Florida’s successful BleachWatch programs.

BleachWatch BCD Tag

BleachWatch BCD Tag. Photo © TNC

Program Development
To guide the development of bleaching response efforts a steering committee was formed. The committee was composed of reef experts from local and federal government resource agencies, non-profit organizations, and academia. The Bleachwatch Program is one of five main components of the US Virgin Islands Reef Resilience Plan (VIRRP), a larger planning effort to conserve coral reefs in the USVI and promote coral reef resilience.

The VI Reef Resilience Plan and steering committee were necessary to generate and document agreed upon protocols between key stakeholders for the Bleachwatch Program. The Plan provides details on the purpose, response activities and triggers, monitoring protocols and community volunteer training. See further details of the plan below:

Assessment and Monitoring
NOAA’s Coral Reef Watch (CRW) Program, provides current reef environmental conditions to identify areas at risk for coral bleaching, and is used to prepare and respond to mass bleaching events. The following CRW products are monitored by The Nature Conservancy (TNC) in the USVI to provide a early warning system: Alert Areas, Hot Spots (current thermal stress), Degree Heating Week (DHW), Sea Surface Temperature (SST) and Sea Surface Temperature Anomaly (SSTA). These products are available free to researchers and stakeholders to understand and better manage coral bleaching in the region.

USVI Bleachwatch response activities are directly based on advisories and alert levels received from NOAA along with local temperature data. When a Bleachwatch alert is received from CRW by TNC, volunteers are mobilized. They are the first eyes in the water, reporting basic observations such as presence or absence of bleaching. Volunteers are asked to collect data for any areas they visit and also asked to survey specific sites of interest such as coral nursery outplantings and sites assessed with high resilience. If a more severe event takes place, TNC alerts the steering committee and the scientific community. During this time, volunteers might continue to assist with monitoring, but data is more specific and collected at a finer scale to estimate of the percentage of coral reef affected.

Alerts are issued by NOAA only when a station experiences a change in thermal stress level. Table 1 presents a summary of the advisories/alert levels from NOAA monitored by TNC, definitions of the each levels and the response of the USVI Bleachwatch program to each advisory.

BleachWatch Table 1

Community Volunteer Training
Individual volunteers from the public are a main component of the USVI Bleachwatch Program and contribute to the assessment of coral bleaching. BleachWatch assessment methods are taught through in-person training sessions (Since 2013, 4 volunteer trainings have been conducted in St. Croix and St. Thomas). Training sessions are 1 hour in length and focus on the identification of corals reef, fishes, and other creatures. Differences between bleaching, disease and mortality are discussed. Each session also includes training on survey methods, materials, methodology and guidelines for submitting data. A USVI Bleachwatch website was developed to communicate with volunteers and the public. Volunteers have the option of submitting reports through an online datasheet, by email or mail.

USVI Bleachwatch Volunteer Survey Methodology
Conduct a 15 minute roving snorkel or dive pausing each 3 minutes to document a “survey station”. At each survey station:

  • Take a photo or record data for a 1 m2 surface area of the reef
  • Estimate percent coral coverage and percent bleaching of coral
  • Report observations of the absence of bleaching
  • Record other findings such as number and types of herbivorous fishes, number and types of invertebrates and types of diseases
  • Record your findings on the VIRRP BleachWatch Reef Assessment Data Sheet

Materials Needed

  • Diving or snorkeling equipment
  • Underwater clipboard or slate
  • Underwater datasheet and pencils
  • Coral Watch Bleaching Cards
  • Underwater digital camera or video camera – if available (optional)

How Successful Has it Been?
Since the launch of the USVI BleachWatch Program over 35 individuals on St. Croix and St. Thomas have been trained to identify and quantify the severity of bleaching. In 2014 the program protocols were tested for the first time. A Bleachwatch alert was sent out and volunteers were successfully mobilized to survey sites for bleaching. Over 30 reports were received and, fortunately, no bleaching was observed. The secondary response components of the program have been fully tested, as there has not been significant bleaching of corals in the territory since 2005.

The USVI Bleachwatch Program has resulted in increased support and capacity for resource managers to identify and respond to bleaching events. Volunteers are functioning as an early warning system for bleaching events. Managers and the scientific community have a clear plan for assessment and response to bleaching events to inform the proactive management of coral reefs during severe bleaching events.

Lessons Learned and Recommendations
The most important lesson learned is to be mindful that not all volunteers will collect data uniformly. In some instances volunteers are comfortable only sharing whether or not bleaching was observed, which is also important information. It is important to be mindful of volunteers’ time and welcome any level of information that they are willing to share.

Here are some additional recommendations to consider when developing a program:

  • Have a point person in place to keep program organized and lead communication with steering committee members and volunteers. During the development of the program it is critical to determine who can serve as point of contact for the program, this requires staff time for coordination. Consider where point of contact responsibilities can be integrated into existing or complementary efforts for example coral reef monitoring efforts.
  • Clearly defining benefits, incentives, and creating a feedback loop to the volunteers is important.
  • Be flexible and realistic about of the quality of data you hope to receive and the format in which you will receive it from the volunteers – some will fill out the entire form, some will just send an email.
  • Provide other alternatives and options for reporting such as a mapping tool to make it easier for people to report the event.
  • Group volunteer time effort – consider expanding the topics included in a training to include other issues affecting coral reef health that volunteers are interested in reporting for example; invasive species, grounding damages.

Funding Summary
National Oceanic and Atmospheric Administration Coral Reef Conservation Program

Lead Organizations
The Nature Conservancy

Partners
The Nature Conservancy
The University of the Virgin Islands Center for Marine and Environmental Studies

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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

Location
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
Seacology
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
View Full Article

Marine Ecology Progress Series 520:1-20

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Community Change and Evidence For Variable Warm-Water Temperature Adaptation Of Corals In Northern Male Atoll, Maldives

This study is a descriptive analysis of coral reef communities in North Male, Maldives seven years after the major 1998 coral bleaching event with the goal of evaluating ongoing changes and ability for adaptation. The study looked at coral community composition, recruitment community, evidence for recovery and responses to corals to a subsequent thermal anomaly in 2005. Eleven shallow reef areas consisting of hard calcium carbonate were assessed using benthic field measurements and bleaching surveys. Maldivian coral recovery showed considerable spatial and taxonomic variability, with dominant taxa characterized by stress tolerance and several previously common taxa now still quite rare. Compared to other Indian Ocean islands, the Maldivian coral response was considerably more variable and complicated. The authors conclude that natural selective processes are in progress with responses showing potential for adaptation.

Author: McClanahan, T.R. and N.A. Muthiga
Year: 2014
View Abstract
Email for the full article: resilience@tnc.org

Marine Pollution Bulletin 80(1-2): 107-113

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Coral Reef Community Composition in the Context of Disturbance History on the Great Barrier Reef, Australia

Spatial assessments of coral reef communities across five reefs of the central Great Barrier Reef were conducted. Reef condition proxies included coral cover, coral composition, coral recruit density, reef structural complexity and fish assemblages. Each reef was characterized by different disturbance histories: two were undisturbed in the past 15 years and three reefs had experienced disturbance (crown-of-thorns sea star outbreaks and/or coral bleaching) 7-10 years prior to the study. Patterns of coral cover and community composition related to a range of other variables (water movement, light penetration and temperature) assessed were thought to be important for reef dynamics. Significant coral community difference in the unrecovered reefs was documented, compared to the composition and cover found on undisturbed reefs. Ecological predictors most strongly correlated to coral composition patterns included density of juvenile corals, herbivore fish biomass, fish species richness and macro-algae cover.

Author: Graham, N.A.J., K.M. Chong-Seng, C. Huchery, F.A. Januchowski-Hartley, and K.L. Nash
Year: 2014
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PLoS ONE 9(7): e101204. doi: 10.1371/journal.pone.0101204

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Retention of Habitat Complexity Minimizes Disassembly of Reef Fish Communities following Disturbance: A Large-Scale Natural Experiment

A natural experiment used data collected over 20 years from reefs spread over 115,000 km2 of the Great Barrier Reef (GBR) to test how the loss of live coral versus loss of habitat complexity influenced reef fish community structure, reef fish diversity and fish species abundance. Reefs from a long-term monitoring program were classified into three treatments based on disturbance effects. On reefs with a major decline in complexity and live coral cover there were substantial shifts in fish and benthic communities. Species abundance declined with local disappearance of some fish species, including commercially valuable species. However, impacts to fish and benthic communities were minor on reefs that lost live coral cover without losing habitat complexity. Overall, habitat complexity is of fundamental importance for reef fishes, and maintaining diverse communities is critical for overall ecosystem health and function.

Author: Emslie, M.J., A.J. Cheal, and A.K. Johns
Year: 2014
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PLoS ONE 9(8): e105384. doi: 10.1371/journal.pone.0105384

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New and improved Network Forum

The Reef Resilience Network has launched a new and improved online discussion forum!

Now part of the Reef Resilience website, this interactive online community is a place where coral reef managers and practitioners from around the world can connect and share with others to better manage marine resources.

If you work to protect, manage, or promote coral reefs please join the conversation: www.reefresilience.org/network

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Assessing Habitat Risk From Human Activities To Inform Coastal And Marine Spatial Planning: A Demonstration In Belize

The expansion of existing and emerging ocean uses has negative effects on ecosystems that provide habitat for key species and benefits to people. Integrated coastal and ocean management needs straightforward approaches for understanding the effects people have on marine environment. In recent years, extensive research has resulted in development of accessible approaches and a better understanding of the relationships between human activities and marine ecosystems. However, some important gaps prevent the use of these approaches in policy-making. This study focuses on the following three impediments to the uptake of risk assessments in coastal management: (1) methods for estimating how habitats will change under future management scenarios; (2) better understanding of the degree to which estimated risk reflects observed environmental degradation; and (3) accessible and transparent tools for incorporating estimated risk into coastal and ocean planning. A model called the Habitat Risk Assessment (HRA) model was developed, which is available in open-source software and can be used by government planners, NGOs, or other stakeholders to assess future scenarios for managing marine ecosystems. To make results more accessible to a policy audience, areas of habitat are classified as high, medium or low risk based on the risk posed by individual activities or by the cumulative effects of multiple activities. The model was used to assess risk to coral reefs, mangrove forests and seagrass beds and to design a spatial plan for the sustainable use of the marine environment of Belize. Results from the analysis and the model developed were used to inform the design of the country’s first Integrated Coastal Zone Management (ICZM) Plan.

This study provides a risk ranking method that calculates risk to ecosystems using two sets of information: (a) exposure, which represents the degree to which the habitat experiences stressors due to a specific human activity and (b) consequence, which reflects the habitat-specific response to stressors associated with different human activities. This method helps identify management options for reducing impacts. In general, management interventions have greater potential to reduce risk via changes in exposure than changes in consequence. New criteria was also developed for estimating risks specific to life history characteristics of the main taxa of coral reefs, mangrove forests and seagrass beds. Criteria developed to estimate exposure and consequence were based on the cumulative impact and risk assessment literature for ecosystem components. To quantify exposure, the model requires information on (a) spatial overlap between habitats and activities; (b) temporal overlap between habitats and activities; (c) intensity of the activity; and (d) effectiveness of management strategies for reducing exposure. To estimate consequence of exposure to human activities, the model requires information on (a) change in area; (b) change in structure; (c) frequency of natural disturbance; and (d) resilience. To estimate risk, the study used information on exposure of corals, mangroves and seagrass in Belize to selected human activities and the consequence of this exposure. The study also evaluates future habitat risk under alternative scenarios such as conservation, informed management and development, to understand the influence of human activities on coral reefs, mangrove forests and seagrass beds in the future. Results suggest that of the three future scenarios, the Conservation option would result in the greatest area of low-risk habitat and least amount at high risk, for all three habitats.

The HRA model presented here identifies both, planning regions where corals, mangroves and seagrass are at high risk, and which activities contributes the most to risk. The information allows managers to prioritize locations for actions to reduce risk by identifying where the spatial extent and exposure of certain high-risk activities can be reduced. In general, the approach presented has the potential to inform multi-sectoral ocean processes by identifying where cumulative risk from human activities is likely to degrade marine habitats, and how changing the location and extent of these activities reduces risk. When combined with models that estimate habitat-induced changes in ecosystem services, the HRA model helps to evaluate trade-offs between human activities and benefits that ecosystems provide to people.

Author: Arkema, K.K., G. Verutes, J.R. Bernhard, C. Clarke, S. Rosado, M. Canto, S.A. Wood, M. Ruckelshaus, A. Rosenthal, M. McField, and J. de Zegher
Year: 2014
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Environmental Research Letters 9. doi:10.1088/1748-9326/9/11/114016

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Contrasting Patterns of Coral Bleaching Susceptibility in 2010 Suggest an Adaptive Response to Thermal Stress

Guest et al. (2012) examine the bleaching and mortality responses of corals at sites in Southeast Asia with different thermal histories during a large-scale bleaching event in 2010 to explore whether corals have the capacity to adapt to elevated sea temperatures. They also assess whether reefs in more thermally variable environments bleach less severely during heat stress events. They found increases in thermal tolerance on reefs that previously experienced major bleaching with the most susceptible species exhibiting the greatest increases in thermal tolerance. They also demonstrated that corals generally bleached less severely at locations where temperature variability has been greater and warming rates lower over the last 60 years. These results are important because they suggest that locations that are more resistant to bleaching can be identified from analyzing their thermal histories, and such sites could be considered priorities for protection in marine protected area (MPAs). These results add to a growing body of evidence suggesting that the capacity for adaptation and acclimatization in corals has been underestimated which is good news for coral reefs.

Author: Guest, J.R., A.H. Baird, J.A. Maynard, E. Muttaqin, A.J. Edwards, S.J. Campbell, K. Yewdall, Y.A. Affendi, and L.M. Chou
Year: 2012
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PLoS ONE 7(3): e33353. doi:10.1371/journal.pone.0033353

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