A survey of current trends and suggested future directions in coral transplantation for reef restoration

Coral transplantation has been used in reef restoration for several decades, but information on the type of projects, their scope, scale, and success is mostly limited to published scientific studies and technical reports. Many practitioners do not have the capacity to share their progress in peer-reviewed literature, yet likely have a wealth of information to share on how to improve the efficiency of transplantation efforts. In order to incorporate non-published data on coral transplantation projects and gain an overview of the general features of these projects, we conducted an initial systematic online survey of projects run by various practitioners. Surveyed projects (n = 50) covered most of the tropical belt and ranged in size from a few hundred transplanted corals to >5000 transplants. The most frequent source of coral fragments were corals already broken from some previous impact (“corals of opportunity”; 58% of projects), followed by fragments stored in different types of aquaculture systems (42% of projects). The use of sexual reproduction was very limited. Fast-growing, branching corals were used in 96% of projects, being by far the most common transplanted growth form. About half of the projects mentioned undertaking maintenance of the transplantation plots. The majority of projects undertook subsequent monitoring (80%), yet the available data indicates that duration of monitoring efforts was not adequate to evaluate long-term success. The findings underline that while some general principles for successful coral restoration projects are reasonably well established, others need to be mainstreamed better in order to improve the effectiveness of coral transplantation for reef restoration. This relates in particular to sustainable funding, adequate site assessment, and long-term monitoring using established protocols. Additional information is needed to better understand and address potential challenges with regards to the sourcing of transplants and use of slow-growing species. A better integration of practitioners is necessary to improve the understanding of coral transplantation effectiveness. The results underline a need to develop and use monitoring protocols that allow gauging and comparing the effectiveness of coral transplantation among various projects, as well as for accessible platform(s) to allow the exchange of experiences made in different projects. Regular surveys of restoration projects are recommended to collate and share information among practitioners. We provide a number of recommendations for items to include in future surveys

Coral restoration effectiveness: multiregional snapshots of the long-term responses of coral assemblages to restoration

Coral restoration is rapidly becoming a mainstream strategic reef management response to address dramatic declines in coral cover worldwide. Restoration success can be defined as enhanced reef functions leading to improved ecosystem services, with multiple benefits at socio-ecological scales. However, there is often a mismatch between the objectives of coral restoration programs and the metrics used to assess their effectiveness. In particular, the scales of ecological benefits currently assessed are typically limited in both time and space, often being limited to short-term monitoring of the growth and survival of transplanted corals. In this paper, we explore reef-scale responses of coral assemblages to restoration practices applied in four well-established coral restoration programs. We found that hard coral cover and structural complexity were consistently greater at restored compared to unrestored (degraded) sites. However, patterns in coral diversity, coral recruitment, and coral health among restored, unrestored, and reference sites varied across locations, highlighting differences in methodologies among restoration programs. Altogether, differences in program objectives, methodologies, and the state of nearby coral communities were key drivers of variability in the responses of coral assemblages to restoration. The framework presented here provides guidance to improve qualitative and quantitative assessments of coral restoration efforts and can be applied to further understanding of the role of restoration within resilience-based reef management

A roadmap to integrating resilience into the practice of coral reef restoration.

Recent warm temperatures driven by climate change have caused mass coral bleaching and mortality across the world, prompting managers, policymakers, and conservation practitioners to embrace restoration as a strategy to sustain coral reefs. Despite a proliferation of new coral reef restoration efforts globally and increasing scientific recognition and research on interventions aimed at supporting reef resilience to climate impacts, few restoration programs are currently incorporating climate change and resilience in project design. As climate change will continue to degrade coral reefs for decades to come, guidance is needed to support managers and restoration practitioners to conduct restoration that promotes resilience through enhanced coral reef recovery, resistance, and adaptation. Here, we address this critical implementation gap by providing recommendations that integrate resilience principles into restoration design and practice, including for project planning and design, coral selection, site selection, and broader ecosystem context. We also discuss future opportunities to improve restoration methods to support enhanced outcomes for coral reefs in response to climate change. As coral reefs are one of the most vulnerable ecosystems to climate change, interventions that enhance reef resilience will help to ensure restoration efforts have a greater chance of success in a warming world. They are also more likely to provide essential contributions to global targets to protect natural biodiversity and the human communities that rely on reefs

Six priorities to advance the science and practice of coral reef restoration worldwide

Coral reef restoration is a rapidly growing movement galvanized by the accelerating degradation of the world's tropical coral reefs. The need for concerted and collaborative action focused on the recovery of coral reef ecosystems coalesced in the creation of the Coral Restoration Consortium (CRC) in 2017. In March 2020, the CRC leadership team met for a biennial review of international coral reef restoration efforts and a discussion of perceived knowledge and implementation bottlenecks that may impair scalability and efficacy. Herein we present six priorities wherein the CRC will foster scientific advancement and collaboration to: (1) increase restoration efficiency, focusing on scale and cost-effectiveness of deployment; (2) scale up larval-based coral restoration efforts, emphasizing recruit health, growth, and survival; (3) ensure restoration of threatened coral species proceeds within a population-genetics management context; (4) support a holistic approach to coral reef ecosystem restoration; (5) develop and promote the use of standardized terms and metrics for coral reef restoration; and (6) support coral reef restoration practitioners working in diverse geographic locations. These priorities are not exhaustive nor do we imply that accomplishing these tasks alone will be sufficient to restore coral reefs globally; rather these are topics where we feel the CRC community of practice can make timely and significant contributions to facilitate the growth of coral reef restoration as a practical conservation strategy. The goal for these collective actions is to provide tangible, local-scale advancements in reef condition that offset declines resulting from local and global stressors including climate change

Ecotourism and coral reef restoration: case studies from Thailand and the Maldives

Coral restoration activities are often time and labour intensive, preventing restoration efforts to be carried out at meaningful spatial and temporal scales. This chapter shows that ecotourism can help address some of the current limitations of coral restoration efforts through two case studies: the Reefscapers program in the Maldives and the New Heaven Reef Conservation Program in Thailand. Using volunteer workforce conveys the advantages of increasing restoration capacity, reducing restoration costs, improving the opportunity to educate the general public to the threats to coral reef ecosystems and building conservation stewardship

Assessing baseline levels of coral health in a newly established marine protected area in a global scuba diving hotspot

While coral reefs are increasingly threatened worldwide, they are also increasingly used for recreational activities. Given the environmental and socio-economic significance of coral reefs, understanding the links between human activities and coral health and evaluating the efficacy of marine protected areas (MPAs) as a management regime to prevent further deterioration are critically important. The aim of this study was to quantify indicators of coral health at sites inside and outside a newly rezoned MPA framework in the dive tourism hotspot of Koh Tao, Thailand. We found that patterns in the health and diversity of coral communities one year on did not reflect the protected status conferred by newly zoned MPAs, but instead reflected past history of recreational use around the island. Sites characterised as past high-use sites had lower mean percent cover of hard corals overall and of corals in the typically disease- and disturbance-susceptible family Acroporidae, but higher mean cover of species in the more weedy family Agariciidae. Past high use sites also had higher mean prevalence of infectious diseases and other indicators of compromised health. Sites within the newly established MPAs are currently subjected to higher levels of environmental and anthropogenic pressures, with sedimentation, algal overgrowth, feeding scars from Drupella snails, and breakage particularly prevalent compared to sites in non-MPA areas. Given the greater prevalence of these factors within protected sites, the capacity of the MPA framework to effectively prevent further deterioration of Koh Tao's reefs is unclear. Nevertheless, our study constitutes a strong baseline for future long-term evaluations of the potential of MPAs to maintain coral health and diversity on highly threatened reefs

Coral restoration: socio-ecological perspectives of benefits and limitations

Coral restoration is increasingly used globally as a management tool to minimize accelerating coral reef degradation resulting from climate change. Yet, the science of coral restoration is still very focused on ecological and technical considerations, impeding the understanding of how coral restoration can be used to improve reef resilience in the context of socio-ecological systems. Here, we visited four well-established coral restoration projects in different regions of the world (Thailand, Maldives, Florida Keys, and US Virgin Islands), and conducted key-informant interviews to characterize local stakeholder's perceptions of the key benefits and limitations associated with restoration efforts. Our results reveal that perceptions around coral reef restoration encompass far more than ecological considerations, and include all four dimensions of sustainability: ecological, social, economic, and governance, suggesting that effective coral restoration should be guided by the principles of sustainability science. Socio-cultural benefits were the most frequently mentioned (72.4% of all respondents), while technical problems were the most common theme for limitations of coral restoration efforts (58.3% of the respondents). Participants also revealed some key points likely to improve the outcomes of coral restoration efforts such as the need to better embrace socio-cultural dimensions in goal setting, evaluate ecological outcomes more broadly, secure long-term funding and improve management and logistics of day to day practices. While we identify several important limitations of coral reef restoration, particularly around amateur workforces and limited involvement of local communities, our results suggest that coral restoration can be used as a powerful conservation education tool to provide hope, enhance agency, promote stewardship and strengthen coral reef conservation strategies

Data from: Seagrass ecosystems reduce exposure to bacterial pathogens of humans, fishes and invertebrates

Plants are important in urban environments for removing pathogens and improving water quality. Seagrass meadows are the most widespread coastal ecosystem on the planet. Although these plants are known to be associated with natural biocide production, they have not been evaluated for their ability to remove microbiological contamination. Using amplicon sequencing of the 16S ribosomal RNA gene, we found that when seagrass meadows are present, there was a 50% reduction in the relative abundance of potential bacterial pathogens capable of causing disease in humans and marine organisms. Moreover, field surveys of more than 8000 reef-building corals located adjacent to seagrass meadows showed twofold reductions in disease levels compared to corals at paired sites without adjacent seagrass meadows. These results highlight the importance of seagrass ecosystems to the health of humans and other organisms

Seagrass ecosystems reduce exposure to bacterial pathogens of humans, fishes, and invertebrates

Plants are important in urban environments for removing pathogens and improving water quality. Seagrass meadows are the most widespread coastal ecosystem on the planet. Although these plants are known to be associated with natural biocide production, they have not been evaluated for their ability to remove microbiological contamination. Using amplicon sequencing of the 16S ribosomal RNA gene, we found that when seagrass meadows are present, there was a 50% reduction in the relative abundance of potential bacterial pathogens capable of causing disease in humans and marine organisms. Moreover, field surveys of more than 8000 reef-building corals located adjacent to seagrass meadows showed twofold reductions in disease levels compared to corals at paired sites without adjacent seagrass meadows. These results highlight the importance of seagrass ecosystems to the health of humans and other organisms

Effects of coral restoration on fish communities: snapshots of long-term, multiregional responses and implications for practice

Coral restoration is widely used around the world to address dramatic declines in coral cover; however, very few studies have looked specifically at the temporal response of fish assemblages (i.e. abundance and diversity) to coral restoration. Several critical reef functions and processes are driven by fishes, thereby making their recovery and responses around restoration structures key indicators of success. This study evaluates fish abundance and community composition on restoration plots following 8–12 years of restoration activity, in four locations (two Caribbean and two Indo‐Pacific). Responses were very complex with region‐, site‐, and body size‐specific patterns. Overall, fish abundance only increased in Indo‐Pacific sites where damselfish responded positively to increased coral cover and topographic complexity. Restoration effects on other fish families and particularly on larger bodied reef fish were negative or neutral at all locations. If restoration initiatives are going to substantively improve the condition and recovery of degraded reef fish communities, restoration efforts need to be planned, designed, and monitored based on fish‐specific habitat requirements and locally specific community dynamics