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Coral Reef Restoration Monitoring Guide: Methods to evaluate restoration success from local to ecosystem scales
Abstract and Figures
As coral restoration efforts continue to increase in size and
number, there is an overwhelming need to define restoration
success and determine progress towards successful restoration.
Meaningful, consistent, comparable, and quantitative data is
required to quantify the changes that result from restoration
actions. However, there may be many definitions of success
depending on the program or project goal(s). Restorations
can have one or many goals that can be very different (e.g.,
ecological, educational), and therefore, goals cannot be
addressed in a “one size fits all” monitoring approach. The
application of quantitative approaches to monitoring not only
provides a reliable way to evaluate progress towards restoration
success, but also provides means to identify problems and apply
adaptive management efforts as needed.
The CRC established a priority for the Restoration Monitoring
Working Group to develop guidance for monitoring coral
reef restorations and to determine restoration success. This
“Coral Reef Restoration Monitoring Guide: Best Practices
for Monitoring Coral Restorations from Local to Ecosystem
Scales” was developed for practitioners and programs in any
stage of their practice: from starting up a new restoration effort,
to scaling up current efforts, to improving efficiency. Coral
restoration practitioners can use the hypotheses- and datadriven
monitoring framework presented in this Guide to make
confident comparisons between projects, programs, and regions,
increase the efficiency of data collection, and make informed
decisions about the data necessary to describe the success of
the restoration goal or objective.
Two categories of coral restoration monitoring metrics are
included in this Guide: Universal Metrics and Goal-Based
Performance Metrics. The four Universal Metrics, Landscape/
Reef-level, Population-level, Colony-level, and Genetic and
Genotypic Diversity, are suggested as basic requirements for
monitoring all restoration projects, regardless of the goal of the
project. These metrics provide data on restoration scale, growth,
survival, and diversity, yet require minimal equipment and time.
These Universal Metrics should be monitored on any restoration
project regardless of the restoration scale, species, habitat,
location, expertise, or budget.
Goal-Based Performance Metrics address five major coral
restoration goals: Ecological Restoration, Socioeconomic, Eventdriven
Restoration, Climate Change Adaptation, and Research.
Metrics are tailored within each goal to address key components
of the goal. For example, when monitoring a restoration with an
ecological goal, a practitioner should evaluate coral condition,
species diversity, habitat quality, and vertebrate and invertebrate
communities, and potentially others. Metrics are detailed for
each goal including key points, suggested methods, reporting
guidelines, and criteria to evaluate the performance towards the
restoration goal and towards restoration success.
Coral reef restoration, while a quickly growing field, is
still relatively new. This document is the first to provide
comprehensive guidance for monitoring coral restorations to
evaluate progress towards meeting restoration goals. Metrics
and associated methods developed herein are based on our
experiences, working group and workshop input, practitioner
interviews, and current published peer reviewed literature and
manuals. While every effort was made to address every situation,
we recognize that as this field develops and the metrics are fully
vetted, some metrics may need to be improved, modified, or
deemed unnecessary. We therefore encourage the evolution of
this Guide as a living document to be updated when necessary
to be relevant and representative. Our experiences and the
examples provided are mainly from the greater Caribbean
region; however, reviews and feedback from practitioners who
have worked globally indicate that the metrics developed are
applicable on coral restorations in all regions.
This Guide should be used to measure and describe the
progress of coral restoration projects towards meeting restoration
goals. The CRC Monitoring Working Group has also developed
a Coral Restoration Database and Evaluation Tool to be
complementary to this Guide and used together. The Coral
Restoration Database allows the input of comparable restoration
projects and monitoring data. The Coral Restoration Evaluation
Tool allows the practitioner to score the performance of their
project, program, or region and determine what is working
well and what needs improvement. The use of this Guide and
feedback provided by practitioners will improve the evaluation of
coral restoration success.
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... New technologies are accelerating the capacity for data collection in coral reef systems. Data science will play a pivotal role in informing-and, in turn, transforming the effectiveness and scale of-reef conservation and restoration ( Fig. 16.1) (Voolstra et al. 2025;Goergen 2020;Voolstra et al. 2021). Automation is extending the temporal and spatial scales with which reef ecological and process-based data can be collected, overcoming the challenges of in-water dive time, and in turn, rapidly moving operational bottlenecks towards how large datasets can be stored and re-accessed, analyzed, and modeled. ...
... Automated and, where possible, standardized data collection in coral reef monitoring will need to incorporate a diverse array of variables, including temperature and chemical sensor data, acoustics and visual data stemming from satellites, drones, divers, or automated underwater vehicles (Voolstra et al. 2025). Integration will facilitate comparison and ef cient mapping and monitoring of coral reefs, signicantly advancing our knowledge through automated reef surveys (Voolstra et al. 2025;Voolstra et al. 2021;Goergen 2020). Achieving this goal requires the development of advanced data storage architectures, robust data management systems, ef cient data transmission protocols, and improved data sharing and accessibility frameworks. ...
... Restoration is one integral part of ensuring a future for coral reefs (Peixoto et al. 2024a;Suggett et al. 2024). Cost, motivation, need, and impact of restoration projects are based on visual assessments, monitoring, and/or predictions that need to be available in a feasible time frame for interventions to be effective (Bayraktarov et al. 2019;Goergen 2020;Lange et al. 2024). Although, in many cases, the damage and coral reef declines are already visible and undeniable, AI/ ML can help to continue to forecast further impacts and support the selection of restoration sites or reserves (Leslie et al. 2003). ...
Based on concepts and data discussed throughout this book, here we introduce the term “Assisted Restoration” (AR) as the sum of approaches required to deliver effective ecological restoration. AR signifies a multidisciplinary strategy with which innovative tools are integrated into routine practices of coral restoration to build sustained resilience for increased survival in a changing world. Coral microbiomes are arguably central targets for active intervention strategies due to their malleability, as well as for monitoring approaches because of their biomarker capacity, serving as indicators of healthy ecosystems. We highlight the role of customized and integrated approaches to optimize coral reef interventions and indicate how artificial intelligence (AI) and standardized data collection methods have the potential to revolutionize the monitoring and analysis of coral reef health under an Assisted Restoration approach. Such an integrative approach is critical to advance ecosystem-scale restoration and is directly connected to planetary and human health under the One Health concept.
... Robust communication of restoration intent and process is central for several fundamental reasons: (1) Scalability of restoration rests-in part-upon effective networks of practice that are built upon a solid foundation of communication and knowledge exchange (e.g., the Coral Restoration Consortium); (2) Precision around definitions is needed for clarity in regards to restoration intent and purpose ; and (3) Consistent terms or definitions enable reconciliation of disparate data sets needed to improve practice (Goergen et al. 2020) and create certainty for investors in what they actually fund and can expect in terms of returns. As such, the growth of restoration as a field and as a practice is-at least in part-constrained by a lack of common lexicon. ...
... Any intention to implement restoration activities starts with setting clear socio-ecological goals and development of underlying targets and objectives (Table 2). Robust operational planning and an effective monitoring strategy are required to track performance that governs perceptions of reef restoration activity "success' (Goergen et al. 2020). Key to performance tracking is expanding focus beyond the intended restoration site to include both "reference" and "control" sites (detailed in Gann et al. 2019) (Table 2). ...
... A critical requirement across the common restoration workflow is effective monitoring of the processes to improve practice as well as measure outcomes relative to restoration goals. Monitoring for restoration is an expansive topic spanning data capture, analysis, reporting, and stewardship that has been evaluated in detail recently and we refer readers to this resource (Goergen et al. 2020). However, we also recognize the need to rapidly advance critical areas including data capture, analysis, storage, and accessibility, which warrants dedicated and detailed consideration beyond current works. ...
Global coral reef restoration efforts continue to diversify in approach, location, and socio-ecological context. In parallel, vocabulary has evolved such that practitioners, scientists, policy makers, communicators, and investors must navigate an increasingly confusing set of terms that are inconsistently defined. Precision around terms and definitions is an important attribute underpinning the rate and extent with which restoration can scale. However, in contrast with more established ecological restoration fields, coral reef restoration lacks a formal lexicon for its core approaches and processes. Here we synthesize, distill, and clarify a core lexicon proposed for coral reef restoration. We navigate readers systematically through terms used for various coral reef restoration approaches, project planning and intent, process workflows, and biological material. We also consider vague terms commonly used that present challenges to singularly define. While we expect this proposed lexicon to continue to evolve, we offer an important first step toward more integrated communications around coral reef restoration.
... A hexagonal grid with units of 10 m 2 was superimposed on each classification. We chose this grid size since 10 m 2 is a common and recommend area for outplanting (Bayraktarov et al. 2019;Goergen et al. 2020), and chose the hexagonal shape because it exhibits superior characteristics in spatial analysis and data visualization due to its unambiguous adjacencies and reduced quantization error (Sahr 2011). We calculated the percentage coverage of each class inside each hexagon and then defined all hexagons as A. palmata that contained at least 0.2% (0.2 m 2 ) of the species. ...
... Furthermore, outplant survival should be assessed on a rigorous basis, as well as any major changes to the overall distribution of the focal species. Monitoring efforts may also include measuring fragment growth, reproductive capacity, and ecosystem traits such as complexity, functional diversity, and community composition across spatial scales (Hein et al. 2017;Goergen et al. 2020). Ongoing monitoring, in conjunction with the modelling approaches we demonstrate here, will improve decision making in terms of where and when to invest future restoration efforts. ...
Context
Restoration is an effective measure to counteract declines of reef-building coral populations. Despite decades of coral restoration research and practice, very little emphasis has been placed on how the spatial distribution of restoration sites influences ecosystem recovery and connectivity.
Objectives
Combining image classification of aerial data with geoinformatics, we aim to identify priority restoration sites to increase the structural connectivity and fertilization potential of coral keystone species.
Methods
We focus on Acropora palmata at two natural reefs with contrasting spatial distributions of the species and include a hypothetical reef with a random distribution as a comparative baseline to represent a highly structurally degraded system. Priority sites are then identified at each reefscape through spatial modelling using three connectivity metrics from classical landscape ecology.
Results
Our models suggest that restoration sites joining or bordering major patches of A. palmata have the greatest potential to increase structural connectivity. Reefs of more degraded status are favourable for restoration because they exhibit a greater increase in connectivity metrics per area restored, while also maximizing the fertilization potential between colonies. Furthermore, the spatial extent that needs to be restored to achieve maximum efficiency is greatly dependent on the initial coverage and distribution of the species.
Conclusions
Our study demonstrates the importance of including spatial planning in the site selection process of coral restoration and provides a methodological framework that can aid in tailoring related strategies in accordance with the spatial arrangement of the target species.
... All criteria and steps used in the design and implementation of the restoration program are described in detail in the planning and design guide for coral reef restoration programs [42][43][44]. ...
... In the case of Francesita, a reef with a smaller area (0.0048 km 2 ) and considering that the ideal sampling area using UDP is c.a. 0.00038 km 2 [44], the restoration efforts carried out in the intervened area (0.001 km 2 ) suggest a positive impact on the changes observed over the whole reef. However, at Manchoncitos (0.15 km 2 ), with an intervened area of 0.0015 km 2 , active restoration efforts should be increased to see results in all the reefs. ...
Coral reefs are threatened by multiple stressors that have driven a decline in the cover of reef-building coral species, resulting in a loss of reef structure and function. Restoration reef science provides useful conservation tools to preserve and restore the key species and ecological functions of these ecosystems. However, gaps remain in restoration at large scales. This study provides a guide of how to invest and apply innovative solutions and immediate action strategies from the tourism-hotel sector in alliance with academia and key stakeholders, through the development and implementation of a multi-species restoration program at two sites in the Mexican Caribbean: Manchoncitos Reef, Riviera Maya and La Francesita Reef, Cozumel. We have identified effective propagation and outplanting techniques for key critically endangered species, as well as genotypes resistant to temperature stress and Stony Coral Tissue Loss Disease (SCTLD), based on pre-restoration nursery trials. We include a comparative analysis over time (2020–2022) showing increased coral cover, structural complexity and fish biomass. Baseline assessment of the study areas will allow adaptation of repopulation techniques not only for hard corals, but also to advance in the comprehensive restoration of the ecosystem, incorporating new elements to the reef, such as fish, crab or sea urchin post larvae. These organisms could accelerate herbivory functions and in turn could improve the natural processes of the coral reefs. Our results improve the understanding of the use of restoration as a tool for climate change adaptation led by the private sector.
... In the meantime, factors such as the importance of the nursery stock, the practitioner context, and weather projections will aid in assessing the risk/reward of shading coral nurseries to protect nursery stock from unfavourable environmental conditions. Our results also further reinforce the importance of considering such site conditions when installing nurseries (Goergen et al. 2020) to ensure suitable steps can be taken in the future to protect stock. ...
Tropical coral reefs are increasingly threatened by more frequent and severe global stressors induced by Anthropogenic climate change. Restoration-based interventions, such as in situ coral propagation and out-planting, are increasingly being adopted to enhance natural recovery. However, these interventions face the same global stressors affecting natural reefs, and hence also need protection. Shading or relocating corals can reduce the severity of coral bleaching, but how such protective interventions are best suited to coral nurseries on the Great Barrier Reef (GBR) remains untested. We therefore conducted a manipulative field experiment factorially crossing two treatments, adding shade structures and lowering of nurseries, to test the efficacy of decreasing solar irradiance during an ocean heatwave to improve coral-bleaching outcomes at two sites on Opal Reef, GBR in 2024. Metrics of coral health (paling and mortality) were monitored for 138 days. The nursery-lowering treatment (from 4 to 7 m) statistically improved bleaching outcomes (less paling and higher survival) at one site, but not the other. Overall, shading nurseries did not reduce coral paling or mortality, suggesting that irradiance may not have been a primary regulator of bleaching severity, or that thermal stress was not severe enough wherein shading would mitigate bleaching. Our results suggest practitioners should first consider lowering coral nurseries where possible ahead of predicted bleaching conditions as this may provide a low-cost low-effort benefit. Consideration of nursery stock importance, practitioner context, and irradiance projections will further help assess the risk/reward of additional shading. We recommend further research could evaluate different shading regimes (e.g., time and length of shading and percentage shade) on nursery corals under higher irradiance conditions.
... These sites should serve as vital demonstrations of the feasibility and efficacy of coral reef restoration techniques (Cook et al. 2022), providing tangible proof of concept to garner support from local communities, governments and other stakeholders. Alongside the establishment of these trial sites, there is a pressing need for the development and implementation of a shared and coherent monitoring programme (Goergen et al. 2020). This programme would facilitate the systematic comparison of restoration outcomes across sites and countries, enabling researchers to evaluate the effectiveness of different restoration approaches. ...
Coral reefs directly support the well‐being of millions of people across Southeast Asia, however, these critical ecosystems are also under immense pressure, threatening their sustainability. Coral reef restoration has emerged as a promising strategy to contribute to safeguarding these critical ecosystems and securing the socioeconomic benefits they provide to local communities across the region. In this paper, we present the outcomes of a week‐long of deliberations between policymakers, research funders, practitioners and scientists from Indonesia, Philippines, Vietnam and Australia, which identified four strategies for building improved capacity for coral reef restoration in Southeast Asia; (i) the creation of a learning network, (ii) addressing critical research needs, (iii) improved approaches to communication and engagement to diverse audiences and (iv) the establishment of sustainable funding mechanisms. These strategies are discussed in detail with a view of providing a roadmap to help support coral reef restoration processes across Southeast Asia.
... US $900,000/km 2 ) (Spalding et al., 2016;De Valck and Rolfe, 2018;Suggett et al., 2023), costs incurred may deliver positive cost-benefit in retaining such value (Naidoo et al., 2006). Further work is needed to confirm this notion via detailed cost-benefit analyses and longerterm, goal-based ecological monitoring that can capture ecological changes underpinning ecosystem function, resilience, and associated ecosystem service value (e.g., Hein et al., 2017;Ladd et al., 2019;Goergen et al., 2020). ...
Implementation of coral restoration practices within reef management strategies is accelerating globally to support reef resilience and recovery. However, full costs underpinning restoration project feasibility have historically been underreported yet are critical to informing restoration cost-benefit decision-making. Such knowledge is especially lacking for Australia’s Great Barrier Reef (GBR), where a coral restoration program led by reef tourism operators, Coral Nurture Program (CNP), was initiated in 2018 (northern GBR) and continues to scale. Here we describe the early outcomes and costs of implementing similar tourism-led asexual coral propagation and outplanting practices in a new region, the Whitsundays (central GBR) through the CNP. Specifically, we detail the local operational and environmental context of CNP Whitsundays, describe the costs of implementation and continuation of restoration activities, as well as evaluate survivorship of coral outplants across three restoration sites for nine months after project establishment (August 2022 to June 2023). Baseline benthic surveys revealed relatively low hard coral cover at restoration sites (ranging from 3.22-8.67%), which significantly differed in benthic composition from coral collection sites (ranging 16.67-38.06%), supporting strong motivation by tourism operators to undertake restoration activities. Mean coral survivorship of coral outplants in fate-tracked plots differed between the three restoration sites after 267 days (ranging 23.33-47.58%), with declines largely driven by coral detachment. Early-stage cost-effectiveness (costs relative to outplant survival) associated with implementation of restoration activity varied widely from US$33.04-178.55 per surviving coral (n = 4,425 outplants) depending on whether ‘in-kind’ costs, restoration activity (outplanting only vs. total costs encompassing planning through to monitoring), site-based survivorship, or a combination of these factors, were considered. As coral reef restoration projects continue to be established globally, our results highlight the need for ongoing, long-term monitoring that can inform adaptive practice, and fully transparent cost-reporting to understand and improve feasibility for any given project. We further highlight the inherent context-dependency of restoration costs, and the importance of considering local social-environmental contexts and their associated cost-benefits in economic rationale for reef restoration projects.
Marine heatwaves (MHWs) are increasingly affecting tropical seas, causing mass coral bleaching and mortality in the wider Caribbean (WC) and eastern tropical Pacific (ETP). This leads to significant coral loss, reduced biodiversity, and impaired ecological functions. Climate models forecast a troubling future for Latin American coral reefs, but downscaled projections for the WC and ETP remain limited. Understanding regional temperature thresholds that threaten coral reef futures and restoration efforts is critical. Our goals included analyzing historical trends in July–August–September–October (JASO) temperature anomalies and exploring future projections at subregional and country levels. From 1940 to 2023, JASO air and ocean temperature anomalies showed significant increases. Projections indicate that even under optimistic scenario 4.5, temperatures may exceed the +1.5 °C air threshold beyond pre-industrial levels by the 2040s and the +1.0 °C ocean threshold beyond historical annual maximums by the 2030s, resulting in severe coral bleaching and mortality. Business-as-usual scenario 8.5 suggests conditions will become intolerable for coral conservation and restoration by the 2030s, with decadal warming trends largely surpassing historical rates, under unbearable conditions for corals. The immediate development of regional and local adaptive coral reef conservation and restoration plans, along with climate change adaptation and mitigation strategies, is essential to provide time for optimistic scenarios to materialize.
Executive summary
● Literature reviews of marine vegetation surveys between 2002-2024 indicate extensive and potentially 100% cover of seagrass and limited information on marine algae in the Thursday Island region.
● Reef Ecologic conducted marine vegetation surveys between 22 and 26 November 2024 using drone, towed underwater video, drop camera, quadrats and field collections.
● Hydrographic survey data of the existing pipeline corridor between Hammond to
Thursday Island indicated undulating topography with small and large deep holes with a maximum depth of 14 m; and Horn to Thursday Island indicated a gentle slope with sand ripples with a maximum depth of 7 m.
● We quantified benthic habitats with the tow video camera methodology for the pipeline area as 39.14% seagrass, 16.20% algae, 2.75% coral, 38.62% sand/silt and 3.27% other.
● The drop camera resulted in very similar benthic habitat with 37.42% seagrass, 18.02% algae, 2.66% coral, 26.37% sand/silt and 15.46% other. The lower percentage of sand\silt is due to targeted drop camera sampling in areas of marine vegetation.
● There were differences between the two pipelines sites with Hammond and Thursday Island containing coral (4.5%), moderate seagrass (26.3%) and marine algae (27.8%) in comparison to Thursday and Horn Island which recorded high seagrass (52.95%) and sand\silt habitats (42.5%).
● The main species of marine vegetation we observed and collected were: Sickle Seagrass Thalassia hemprichii, Tape Seagrass Enhalus acoroides, Sea Wrack Halophila ovalis and Sargassum spp.
● We did not observe any significant coral outcrops or coral bommies along the survey
area. We did observe and record hard and soft corals including Salad Coral Turbinaria
mesenterina.
● An estimated total direct footprint for installing two 3850 m cables on the substrate 1m apart and adjacent to the existing water pipeline is impact to 7641.6 m2 of marine
vegetation, (comprising 5,877.2 m2 seagrass, 1764.4 m2 algae) and 422 m2 of coral.
● Based on potential impact footprints of 5 and 20 m wide cable installation we estimated temporary impacts to marine plants of 9552 m2 and 38208 m2.
● We conclude that the cable works will involve temporary impacts and benefits to fish habitats as fish generally feed and shelter adjacent to hard structures. We conclude that there will be no permanent impacts to marine vegetation or fish habitat as the cables will generally be buried by shifting sediment or natural recruitment of seagrass and algae will occur.
● Species of marine vegetation and other marine life were added to iNaturalist projects to increase local knowledge. As of 10 February 2025 the project has accumulated 1605 observations of 360 species with the most common observations: Ringed Sap-sucking Slug Plakobranchus ocellatus, Erroneous Cowry Erronea errones, Spotted Mangrove Rhizophora stylosa and Thorny Oysters Genus Spondylus
Anthropogenic stressors like overfishing, land based runoff, and increasing temperatures cause the degradation of coral reefs, leading to the loss of corals and other calcifiers, increases in competitive fleshy algae, and increases in microbial pathogen abundance and hypoxia. To test the hypothesis that corals would be healthier by moving them off the benthos, a common garden experiment was conducted in which corals were translocated to midwater geodesic spheres (hereafter called Coral Reef Arks or Arks). Coral fragments translocated to the Arks survived significantly longer than equivalent coral fragments translocated to Control sites ( i.e ., benthos at the same depth). Over time, average living coral surface area and volume were higher on the Arks than the Control sites. The abundance and biomass of fish were also generally higher on the Arks compared to the Control sites, with more piscivorous fish on the Arks. The addition of Autonomous Reef Monitoring Structures (ARMS), which served as habitat for sessile and motile reef-associated organisms, also generally significantly increased fish associated with the Arks. Overall, the Arks increased translocated coral survivorship and growth, and exhibited knock-on effects such as higher fish abundance.
Monitoring the state of coral reefs is necessary to identify drivers of change and assess effectiveness of management actions. There are several widely-used survey methods, each of which is likely to exhibit different biases that should be quantified if the purpose is to combine datasets obtained via different survey methods. The latter is a particularly important consideration when switching methodologies in long-term monitoring programs and is highly relevant to the Caribbean today. This is because of the continuing need for regionally comparable coral reef monitoring datasets and the fact that the Global Coral Reef Monitoring Network (GCRMN)-Caribbean node is now recommending a photoquadrat (PQ) method over the chain intercept transect method widely adopted by the members of the first truly regional monitoring network, Caribbean Coastal Marine Productivity Program (CARICOMP), in the early-1990s. Barbados, a member of the CARICOMP network, has been using a variation of the chain intercept method in its long-term coral reef monitoring program for more than two decades. Now a member of GCRMN-Caribbean, Barbados is considering switching to the PQ method in conformity with other regional members. Since we expect differences between methods, this study seeks to quantify the nature of those differences to inform Barbados and others considering switching methods. In 2017, both methods were concurrently implemented at 21 permanent monitoring plots across three major reef types in Barbados. Differences in % cover estimates for the six major benthic components, that is, hard corals, sponges, gorgonians, macroalgae, turf algae and crustose coralline algae, were examined within and among reef types. Overall, we found a complex pattern of differences between methods that depended on the benthic component, its relative abundance, and the reef type. We conclude that most benthic components would require a different conversion procedure depending on the reef type, and we provide an example of these procedures for Barbados. The factors that likely contribute to the complex pattern of between-method differences are discussed. Overall, our findings highlight that switching methods will be complicated, but not impossible. Finally, our study fills an important gap by underscoring a promising analytical framework to guide the comparison of ecological survey methods on coral reefs.
Caribbean reef corals have experienced unprecedented declines from climate change, anthropogenic stressors and infectious diseases in recent decades. Since 2014, a highly lethal, new disease, called stony coral tissue loss disease, has impacted many reef-coral species in Florida. During the summer of 2018, we noticed an anomalously high disease prevalence affecting different coral species in the northern portion of the Mexican Caribbean. We assessed the severity of this outbreak in 2018/2019 using the AGRRA coral protocol to survey 82 reef sites across the Mexican Caribbean. Then, using a subset of 14 sites, we detailed information from before the outbreak (2016/2017) to explore the consequences of the disease on the condition and composition of coral communities. Our findings show that the disease outbreak has already spread across the entire region by affecting similar species (with similar disease patterns) to those previously described for Florida. However, we observed a great variability in prevalence and tissue mortality that was not attributable to any geographical gradient. Using long-term data, we determined that there is no evidence of such high coral disease prevalence anywhere in the region before 2018, which suggests that the entire Mexican Caribbean was afflicted by the disease within a few months. The analysis of sites that contained pre-outbreak information showed that this event considerably increased coral mortality and severely changed the structure of coral communities in the region. Given the high prevalence and lethality of this disease, and the high number of susceptible species, we encourage reef researchers, managers and stakeholders across the Western Atlantic to accord it the highest priority for the near future.
Coral decline in the Caribbean is marked by the loss of habitat-forming corals, such as elkhorn coral (Acropora palmata). Elkhorn coral recovery has been isolated and patchy, but recently a “re-sheeting” phenomenon, in which elkhorn tissue grows over standing dead coral skeletons, was observed along the reefs in the Mexican Yucatán peninsula. Little is known about the ecological factors contributing to “re-sheeting,” but it is hypothesized that grazing from herbivores provides top-down control of algal growth and promotes coral recovery. The purpose of this study was to evaluate the status of elkhorn populations in Akumal, Mexico and determine if Diadema urchins or parrotfish populations are associated with higher elkhorn abundance and lower algal cover. To achieve this objective, we surveyed 12 spur and groove reef sites in Akumal, where re-sheeting was recently observed, and measured elkhorn coral and herbivore population metrics. We found that both herbivore groups are associated with increasing elkhorn coral presence and cover, and lower macroalgal cover. Additionally, we tested for sampling bias in counting Diadema urchins and found that a significant difference in urchins counts between paired day and night transects on shallow, high complexity reefs. Our results suggest that historically important herbivore groups may be contributing to the recovery of elkhorn coral in Akumal by facilitating tissue re-sheeting.
Ecological restoration, when implemented effectively and sustainably, contributes to protecting biodiversity; improving human health and wellbeing; increasing food and water security; delivering goods, services, and economic prosperity; and supporting climate change mitigation, resilience, and adaptation. It is a solutions-based approach that engages communities, scientists, policymakers, and land managers to repair ecological damage and rebuild a healthier relationship between people and the rest of nature. When combined with conservation and sustainable use, ecological restoration is the link needed to move local, regional, and global environmental conditions from a state of continued degradation, to one of net positive improvement. The second edition of the International Principles and Standards for the Practice of Ecological Restoration (the Standards) presents a robust framework for restoration projects to achieve intended goals, while addressing challenges including effective design and implementation, accounting for complex ecosystem dynamics (especially in the context of climate change), and navigating trade-offs associated with land management priorities and decisions.
Active coral restoration typically involves two interventions: crossing gametes to facilitate sexual larval propagation; and fragmenting, growing, and outplanting adult colonies to enhance asexual propagation. From an evolutionary perspective, the goal of these efforts is to establish self‐sustaining, sexually reproducing coral populations that have sufficient genetic and phenotypic variation to adapt to changing environments. Here, we provide concrete guidelines to help restoration practitioners meet this goal for most Caribbean species of interest. To enable the persistence of coral populations exposed to severe selection pressure from many stressors, a mixed provenance strategy is suggested: genetically unique colonies (genets) should be sourced both locally as well as from more distant, environmentally distinct sites. Sourcing three to four genets per reef along environmental gradients should be sufficient to capture a majority of intraspecies genetic diversity. It is best for practitioners to propagate genets with one or more phenotypic traits that are predicted to be valuable in the future, such as low partial mortality, high wound healing rate, high skeletal growth rate, bleaching resilience, infectious disease resilience, and high sexual reproductive output. Some effort should also be reserved for underperforming genets because colonies that grow poorly in nurseries sometimes thrive once returned to the reef and may harbor genetic variants with as yet unrecognized value. Outplants should be clustered in groups of four to six genets to enable successful fertilization upon maturation. Current evidence indicates that translocating genets among distant reefs is unlikely to be problematic from a population genetic perspective but will likely provide substantial adaptive benefits. Similarly, inbreeding depression is not a concern given that current practices only raise first‐generation offspring. Thus, proceeding with the proposed management strategies even in the absence of a detailed population genetic analysis of the focal species at sites targeted for restoration is the best course of action. These basic guidelines should help maximize the adaptive potential of reef‐building corals facing a rapidly changing environment.
In September 2017, major Hurricanes Irma and Maria impacted Puerto Rico and the U.S. Virgin Islands (USVI) and caused considerable damage to shallow coral reefs. In February 2018, at the request of the Puerto Rico Department of Natural and Environmental Resources (PRDNER), the Federal Emergency Management Agency (FEMA) assigned the National Oceanic and Atmospheric Administration (NOAA) to conduct coral reef assessments and emergency coral stabilization activities in Puerto Rico as part of the Hurricane Maria response under the National Disaster Recovery Framework Natural and Cultural Resources Recovery Support Function. A total of 414,354 m2 of coral reef area, including over 87,000 corals, were assessed at 150 sites across Puerto Rico between February 27 and May 7, 2018. More than 8,700 corals were reattached at 35 reef sites in Puerto Rico. Prior to the FEMA effort, coral stabilization efforts were supported by NOAA and the National Fish and Wildlife Foundation (NFWF) in Puerto Rico and St. Thomas, USVI and reattached more than 7,500 corals at 28 additional sites. In total, coral stabilization efforts in PR and the USVI reattached 16,000 corals at 63 sites.
Coral reef restoration is gaining considerable momentum globally in response to climate change and other anthropogenic impacts on coral reefs. In Australia, as part of the Reef Restoration and Adaptation Program (RRAP), a range of unconventional interventions are currently being investigated to help the Great Barrier Reef resist, repair and recover from climate change. Many of these interventions are based on innovative approaches, such as assisted evolution. The regulatory environment is likely to be critical in determining the feasibility and viability of reef restoration and adaptation interventions. It influences what, where and how to restore, who should be responsible for, engaged in, and benefit from restoration. This study explores the regulatory implications of proposed restoration and adaptation interventions in the context of the Great Barrier Reef. This includes mapping the existing regulatory and governance landscape, establishing an approach to account for regulatory requirements of restoration and adaptation interventions, and examining regulatory issues associated with their development and deployment. The study also scopes administrative capacity; i.e., the capacity of regulators in terms of resources and skills required to assess novel risks and impacts of reef restoration and adaptation interventions. It provides important insights that may prove useful for other jurisdictions, where ecosystem restoration and adaptation has become an imperative under a fast-changing climate.
This paper presents a multi-temporal underwater photogrammetric survey of a reef patch located in Moorea, French Polynesia, designed to detect a coral growth of 10–15 mm/year. Structure-from-Motion photogrammetry and underwater imagery allows the three-dimensional quantification of reef structural complexity and ecologically relevant characteristics at the patch scale. A high degree of accuracy and fine resolution are required in order to guarantee the repeatability of surveys over time within the same reference system, meaning a proper geodetic network and acquisition scheme are mandatory. Measuring tools and reference points were properly designed in order to constrain the photogrammetric reconstruction. The network adjustment, performed with distance and height difference observations, provided an average accuracy of ± 1.2 mm and ± 2.9 mm in the horizontal and vertical components, respectively. The final accuracies of photogrammetric reconstructions are on the order of 1 cm and few millimeters for the 2017 and 2018 monitoring campaigns, respectively. This results in realized errors in the comparison of about ± 1 cm. Coordinate variations larger than this magnitude can be reasonably interpreted as coral growth or dissolution. The direct comparison of the two subsequent point clouds is effective in order to evaluate trends in growth and perform morphometric analyses. For highly accurate quantitative assessment of local changes, an expert operator can create and analyze specific 2D profiles that are easily produced from the point clouds.