1. About this book

©2025 Thornton et al., CC BY-NC 4.0 https://doi.org/10.11647/OBP.0453.01

The Conservation Evidence project

The Conservation Evidence project has four main parts:

  1. The synopses of the evidence captured for the conservation of particular species groups or habitats, such as this synopsis. Synopses bring together the evidence for each possible action (also known as an intervention). They are freely available online and, in some cases, available to purchase in printed book form.
  2. An ever‐expanding database of summaries of previously published scientific papers, reports, reviews or systematic reviews that document the effects of actions. This resource comprises over 8,700 pieces of evidence, all available in a searchable database on the website https://www.conservationevidence.com.
  3. What Works in Conservation, which is an assessment of the effectiveness of actions by expert panels, based on the collated evidence for each action for each species group or habitat covered by our synopses. This is available as part of the searchable database and is published as an updated book edition each year (https://www.conservationevidence.com/content/page/79).
  4. An online, open access journal Conservation Evidence publishes new pieces of research on the effects of conservation management actions. All our papers are written by, or in conjunction with, those who carried out the conservation work and include some monitoring of its effects (https://conservationevidencejournal.com/).

The purpose of Conservation Evidence synopses

Conservation Evidence synopses do

Conservation Evidence synopses do not

  • Bring together scientific evidence captured by the Conservation Evidence project (over 7,800 studies so far) on the effects of actions to conserve biodiversity
  • Include evidence on the basic ecology of species or habitats, or threats to them
  • List all realistic actions for the species group or habitat in question, regardless of how much evidence for their effects is available
  • Make any attempt to weigh or prioritize actions according to their importance or the size of their effects
  • Describe each piece of evidence, including methods, as clearly as possible, allowing readers to assess the quality of evidence
  • Weigh or numerically evaluate the evidence according to its quality
  • Work in partnership with conservation practitioners, policymakers and scientists to develop the list of actions and ensure we have covered the most important literature
  • Provide recommendations for conservation problems, but instead provide scientific information to help with decision-making

Who this synopsis is for

If you are reading this, we hope you are someone who makes decisions about how best to support or conserve biodiversity. You might be a resource manager, a conservationist in the public or private sector, a fisher, a campaigner, an advisor or consultant, a policymaker, a researcher or someone taking action to protect your own local wildlife or reef. Our synopses summarize scientific evidence relevant to your conservation objectives and the actions you could take to achieve them.

We do not aim to make your decisions for you, but to support your decision‐making by telling you what evidence there is (or isn’t) about the effects that your planned actions could have.

When decisions must be made with particularly important consequences, we recommend carrying out a systematic review, as the latter is likely to be more comprehensive than the summary of evidence presented here. Guidance on how to carry out systematic reviews can be found at the Collaboration for Environmental Evidence (Guidelines for Authors – Environmental Evidence).

Background

Corals (Phylum: Cnidaria), including the stony corals as well as soft and cold-water species, are found in a diverse range of marine habitats in tropical, temperate, and arctic waters from shallow coasts all the way down to the deep sea. Formed over many thousands of years, corals can form reefs which develop when larvae from reef-building stony corals (also known as hard or scleractinian corals) settle on hard substrate at the edge of an island or volcano. As individual polyps grow and the hard calcium carbonate skeleton forms to support the polyps, the colony grows. Despite covering just 0.2% of the ocean floor, coral reefs are believed to support more than 25% of marine species (Souter et al. 2021). Corals are threatened by anthropogenic impacts, such as land-use change (urban, industrial and agricultural), nutrient enrichment, chemical and noise pollution, resource exploitation, damage from fishing gear and destructive fishing activity, invasive species, disease, and declining water quality (Souter et al. 2021). Climate change and increasing levels of atmospheric greenhouse gases continue to have serious direct and indirect effects, including ocean acidification, more frequent bleaching events and increasing frequency and intensity of storms (Hein et al. 2020). The Status of the Coral Reefs of the World 2020 report, by the Global Coral Reef Monitoring Network (GCRMN) reported that between 2009 and 2018 there was a loss of 14% of the global average cover of stony (hard) coral on the world’s coral reefs (Souter et al. 2021).

Although all corals face broadly similar threats, actions aimed at conserving or restoring corals will vary depending on the communities/composition of species and where the reef is located. Actions can be considered within three broad themes i) protection of healthy reefs (e.g. use of Marine Protected Areas), ii) measures to reduce impact of threats (e.g. fisheries management, pollution control), and iii) active restoration (e.g. ex-situ cultivation, transplanting). As coral colonies can take many years or even centuries to recover from damage (Boch et al. 2019), the priority should be effective measures to protect existing reefs, and colonies, followed by measures to mitigate anthropogenic impacts and threats. Restoration should work in conjunction with protection and mitigation (Montero-Serra et al. 2019; Boström-Einarsson et al. 2020; Souter et al. 2021). All these measures must be combined with global efforts to tackle climate change and reduce the devastating impact on the world’s corals such as a rise in ocean temperature and increased ocean acidification, as well as the equally deleterious impacts of excess nutrient input and eutrophication (Silbiger et al. 2018).

Evidence-based knowledge is key for planning successful conservation and/or restoration strategies and for the cost-effective allocation of scarce resources for conservation and restoration programmes. However, there is a paucity of evidence within the literature for the effectiveness of actions aimed at coral conservation or reef restoration (Shaver et al. 2018). Reviews of some conservation actions (e.g. Marine Protected Areas) have been carried out (e.g. Pendleton et al. 2018; Montero-Serra et al. 2018, NASEM 2019, Boström-Einarsson et al. 2020). However, the evidence for the effectiveness of all actions targeting coral conservation or reef restoration has not yet been synthesized and assessed under a formal review.

Here, we use a subject-wide evidence synthesis approach (Sutherland & Wordley 2018, Sutherland et al. 2019) to simultaneously summarize the evidence for the wide range of practical actions dedicated to the protection, conservation and restoration of all corals (including stony, soft, and deep-water species in tropical, temperate, or deep-sea environments). By simultaneously targeting the range of potential actions, we can review the evidence for each action cost-effectively, and the resulting synopsis can be updated periodically and efficiently to incorporate new research. This synopsis is freely available at https://www.conservationevidence.com and, alongside the Conservation Evidence online database (comprising all summarized information from the synopsis along with expert assessment scores), should be a valuable asset to the toolkit of practitioners and policy makers seeking sound information to support coral reef conservation and restoration.

Scope of the Coral Conservation synopsis

Review subject

This synthesis collates global evidence for the effectiveness of all conservation and restoration actions for all corals (including stony, soft, and deep-water species) on reefs (fringing, barrier, patch, and atoll) in tropical, temperate, or cold-water environments. The synopsis focuses on summarizing evidence for practical actions including, but not limited to, designating Marine Protected Areas, cultivating corals both in-situ and ex-situ, transplanting coral fragments, and stabilizing damaged reefs. We include corals on reefs in shallow waters through the mesophotic zone (reduced light penetration at 30–150 m depth) down to the deep sea. This subject has not yet been covered using subject-wide evidence synthesis. This is defined as a systematic method of reviewing and synthesising evidence that covers broad subjects (in this case conservation and restoration of corals) at once, including all closed review topics within that subject at a fine scale, and analysing results through study summary and expert assessment, or through meta-analysis. The term can also refer to any product arising from this process (Sutherland et al. 2019). The topic is therefore a priority for the discipline-wide Conservation Evidence database.

Evidence for the effectiveness of actions targeting the conservation of other aquatic or semi-aquatic species that rely on coral reef habitats (such as fishes, invertebrates, etc.) are covered in separate synopses.

In relation to active restoration actions, we did not include evidence from the substantial literature on the commercial cultivation of coral species solely for the aquarium trade. However, we included these actions where they were relevant to the conservation of wild declining or threatened species (e.g. cultivation and propagation of coral species for the purpose of reintroductions). We also included actions designed to restore coral reef habitat by transplanting ex-situ nursery-cultivated coral on to man-made structures (e.g. frames) or natural surfaces (e.g. existing dead coral, rocks, or crevices on the sea floor); a process known as ‘coral gardening’. Actions relating to enhancing artificial structures in the marine environment, other than for the purposes of coral reef restoration, are published in other synopses and will not be considered here. For this synthesis, restoration actions include those that aim to restore corals.

Methods

Literature searches

Literature was obtained from the Conservation Evidence discipline-wide literature database, and from searches of additional subject specific literature sources. The Conservation Evidence discipline-wide literature database is compiled using systematic searches of journals and organisational reports; relevant publications describing studies of conservation actions for all species groups and habitats are saved from each search and are added to the database.

  1. Global evidence

Evidence from all around the world is included.

  1. Languages included

A recent study on the topic of language barriers in global science indicates that approximately 35% of conservation studies may be in non-English languages (Amano et al. 2016). Therefore, journals published in a total of 17 languages have been searched and relevant papers extracted by Conservation Evidence:

  • Arabic (11 journals)
  • Chinese, simplified (61 journals)
  • Chinese, traditional (14 journals)
  • English (over 330 journals)
  • French (13 journals)
  • German (40 journals)
  • Hungarian (4 journals)
  • Indonesian (1 journal)
  • Italian (7 journals)
  • Japanese (20 journals)
  • Korean (5 journals)
  • Persian (9 journals)
  • Polish (10 journals)
  • Portuguese (29 journals)
  • Russian (12 journals)
  • Spanish (63 journals)
  • Turkish (27 journals)
  • Ukrainian (4 journals)

Journals listed as “English” are either published in English or at least carry English summaries (Appendix 1). Non-English-language journals are listed in Appendix 2. All relevant papers were added to the Conservation Evidence discipline-wide literature database (see below).

  1. Journals searched
  1. From Conservation Evidence discipline-wide literature database

All of the journals (and years) listed in Appendix 1 and Appendix 2 had already been searched and relevant papers added to the Conservation Evidence discipline-wide literature database. An asterisk indicates the journals most relevant to this synopsis. Others are less likely to have included papers relevant to this synopsis, but if they did, they will be summarized.

  1. Update searches

Due to time constraints, we did not update journal searches. However, we did undertake new searches of more relevant journals (see list below).

  1. New searches

In addition to the list of journals in Appendix 1, specialist journal searches were carried out for studies published from 2000–2021 in the journals Coral Reefs and Bulletin of Marine Science. There was no time to conduct focused searches of other journals relevant to the conservation or restoration of coral reefs listed below. Searches of these journals may be carried out at a later date and added to any future synopsis update.

  • Ecological Engineering
  • Ocean & Coastal management
  • Marine Biology
  • Marine Policy
  • Estuarine Coastal and Shelf Science
  • Western Indian Ocean Journal of Marine Science
  • Deep Sea Research II
  • Marine Biodiversity
  1. Reports from specialist websites searched
  1. From Conservation Evidence discipline-wide literature database

All of the report series (and years) shown in Appendix 3 had already been searched for the Conservation Evidence project. An asterisk indicates the report series most relevant to this synopsis. Others are less likely to have included reports relevant to this synopsis, but if they did, they were summarized.

  1. Update searches

Due to time constraints, we did not update report searches. However, we undertook new searches of more relevant reports (see list below).

  1. New searches

New searches of targeted specialist reports relevant to coral reef conservation and restoration as listed below. These searches reviewed every report title and abstract or summary within each report series (published before the end of 2021) and any relevant reports were added to the project database.

The following resource has published over 9,000 reports and therefore a systematic search of every title was not possible within the time frame of this project. Instead, key-word searches (for ‘coral’, ‘reef’, ‘atoll’, ‘zooxanthellae’) were carried out within the topic.

  1. Other literature searches

The online database https://www.conservationevidence.com was searched for relevant publications that have already been summarized.

  1. Reviews or supplementary literature identified by advisory board or relevant stakeholders

There were no reviews identified and summarized for this synopsis. New or collective data from reviews (both systematic and non-systematic) were summarized as part of the broader synthesis covering the effectiveness of all conservation and restoration actions for coral reefs. An example of new data would be previously unpublished data from a case study, which may be used to support or illustrate points arising from the review. Examples of collective data would be a meta-analysis of results from previously published studies, a table listing the survival rate of transplanted corals in previously published studies, or a combination of multiple published studies to describe long-term changes in one restoration site. Summary paragraphs for reviews will indicate which other summarized studies they include (if any). Due to time constraints, reviews will not be used to identify further publications to summarize unless they are explicitly identified by the advisory board.

  1. Search record database

A database was created of all relevant publications found during searches. Reasons for exclusion were recorded for all those included during screening that were not summarized for this synopsis.

Publication screening and inclusion criteria

  1. Screening

To ensure consistency/accuracy when screening publications for inclusion in the literature database, an initial test using the Conservation Evidence inclusion criteria (provided below) and a consistent set of references was carried out by authors, compared with the decisions of the experienced core Conservation Evidence team. Results were analysed using Cohen’s Kappa test (Cohen 1960). Where initial results did not show ‘substantial’ (K = 0.61–0.8) or ‘almost perfect’ agreement (K = 0.81–1.0), authors were given further training. A second Kappa test was used to assess the consistency/accuracy of article screening for the first two years of the first journal searched by each author. Again, where results did not show ‘substantial’ (K = 0.61–0.8) or ‘almost perfect’ agreement (K = 0.81–1.0), authors received further training before carrying out further searches.

Authors of other synopses who have searched journals and added relevant publications to the Conservation Evidence literature database since 2018, and all other searchers since 2017 have undertaken the initial paper inclusion test described above; searchers prior to that have not. Kappa tests have been conducted on the first two years of searches carried out by all new contributors to the Conservation Evidence literature database since July 2018.

We acknowledge that the literature search and screening method used by Conservation Evidence, as with any method, will result in gaps in the evidence. The Conservation Evidence literature database currently includes relevant papers from over 330 English language journals as well as over 320 non-English journals. Additional journals are frequently added to those searched, and years searched are often updated. It is possible that searchers will have missed relevant papers from those journals searched. Publication bias has not been taken into account, and it is likely that additional biases will result from the evidence that is available, for example there are often geographic biases in study locations.

  1. Inclusion criteria

The following Conservation Evidence inclusion criteria were used.

Criteria A: Conservation Evidence includes studies that measure the effect of an action that might be done to conserve biodiversity

  1. Does this study measure the effect of an action that is or was under the control of humans, on wild taxa (including captives), habitats, or invasive/problem taxa? If yes, go to 3. If no, go to 2.
  2. Does this study measure the effect of an action that is or was under the control of humans, on human behaviour that is relevant to conserving biodiversity? If yes, go to Criteria B. If no, the study will be excluded.
  3. Could the action be put in place by a conservationist/decision maker to protect, manage or restore wild taxa or habitats, reduce impacts of threats to wild taxa or habitats, or control or mitigate the impact of the invasive/problem taxon on wild taxa or habitats? If yes, the study will be included. If no, the study will be excluded.

Explanation:

1a. Study must have a measured outcome on wild taxa, habitats or invasive species: excludes studies on domestic/agricultural species, theoretical modelling or opinion pieces. See Criteria B for actions that have a measured outcome on human behaviour only.

1b. Action must be carried out by people: excludes impacts from natural processes (e.g. wave action, natural storms), impacts from background variation (e.g. sediment type, climate change), correlations with habitat types, where there is no test of a specific action by humans, or pure ecology (e.g. movement, distribution of species).

2. Study must test an action that could be put in place for conservation. This excludes assessing impacts of threats (actions which remove threats would be included). The test may involve comparisons between sites/factors not originally put in place or modified for conservation, but which could be (e.g. fished vs unfished sites, dredged vs undredged sites – where the removal of fishing/dredging is as you would do for conservation, even if that was not the original intention in the study).

If the title and/or abstract are suggestive of fulfilling our criteria, but there is not sufficient information to judge whether the action was under human control, the action could be applied by a conservationist/decision maker or whether there are data quantifying the outcome, then the study was included. If the article has no abstract, but the title is suggestive, then a study was included.

We sort articles into folders by which taxon/habitat they have an outcome on. If the title/abstract does not specify which species/taxa/habitats are impacted, then the full article was searched and then assigned to folders accordingly.

The outcome for wild taxa/habitats can be negative, neutral or positive, does not have to be statistically significant but must be quantified (if hard to judge from abstract, then it will be included). It could be any outcome that has implications for the health of individuals, populations, species, communities or habitats, including, but not limited to the following:

  • Individual health, condition or behaviour, including in captivity: e.g., growth, size, weight, stress, disease levels or immune function, movement, use of natural/artificial habitat/structure, range, or predatory or nuisance behaviour that could lead to retaliatory action by humans
  • Breeding: egg/sperm production, sperm motility/viability after freezing, artificial fertilization success, mating success, birth rate, litter size, calf/pup condition, ‘overall recruitment’
  • Genetics: genetic diversity, genetic suitability (e.g. adaptation to local conditions, use of correct flyways for migratory species, etc.)
  • Life history: age/size at maturity, survival, mortality
  • Population measures: number, abundance, density, presence/absence, biomass, movement, cover, age-structure, species distributions (only in response to a human action), disease prevalence, sex ratio
  • Community/habitat measures: species richness, diversity measures (including trait/functional diversity), community composition, community structure (e.g. trophic structure), area covered (e.g. by different habitat types), physical habitat structure (e.g. rugosity, height, basal area)

Actions within the scope of Conservation Evidence include:

See https://www.conservationevidence.com/data/index for more examples of actions.

Note on study types:

Literature reviews, systematic reviews, meta-analyses or short notes that review studies that fulfil these criteria were included.

Theoretical modelling studies were excluded, as no action has been taken. However, studies that use models to analyse real-world data, or compare models to real-world situations were included (if they otherwise fulfil these criteria).

Criteria B: Conservation Evidence includes studies that measure the effect of an action that might be done to change human behaviour for the benefit of biodiversity

  1. Does this study measure the effect of an action that is or was under human control on human behaviour (actual or intentional) which is likely to protect, manage or restore wild taxa or habitats, or reduce threats to wild taxa or habitats? If yes, go to 2. If no, the study will be excluded.
  2. Could the action be put in place by a conservationist, manager or decision maker to change human behaviour? If yes, the study will be included. If no, the study will be excluded.

Explanation:

1a. Study must have a measured outcome on actual or intentional human behaviour including self-reported behaviours: excludes outcomes on human psychology (tolerance, knowledge, awareness, attitude, perceptions or beliefs).

1b. Change in human behaviour must be linked to outcomes for wild taxa and habitats, excludes changes in behaviour linked to outcomes for human benefit, even if these occurred under a conservation program (e.g. we would exclude a study demonstrating increased school attendance in villages under a community-based conservation program).

1c. Action must be under human control: excludes impacts from climatic or other natural events.

2. Study must test an action that could be put in place for conservation: excludes studies with no action, e.g. correlating human personality traits with likelihood of conservation-related behaviours.

The human behaviour outcome of the study can be negative, neutral or positive, does not have to be statistically significant but must be quantified (if hard to judge from abstract, then it was included). It could be any behaviour that is likely to have an outcome on wild taxa and habitats (including mitigating the impact of invasive/problem taxon on wild taxa or habitats). Actions include, but are not limited to the following:

Actions which are particularly likely to have a behaviour change outcome include, but are not limited to the following:

We allocated studies to folders by their outcome. All studies under Criteria B went in the ‘Behaviour change’ folder. They were additionally duplicated into a taxon/habitat folder if there was a specific intended outcome of the behaviour change (if none mentioned, they were filed only in Behaviour change).

  1. Relevant subject

Studies relevant to the synopsis subject included those focused on the conservation or restoration of coral reefs.

  1. Relevant types of action

An action has to be one that could be put in place by a manager, conservationist, policy maker, advisor or consultant to protect, manage or restore coral reefs or reduce the impacts of threats to them. Alternatively, actions may aim to change human behaviour (actual or intentional), which is likely to protect, manage or restore coral reefs or reduce threats to them. See inclusion criteria above for further details.

If the following two criteria were met, a combined action was created within the synopsis, rather than duplicating evidence under all the separate actions: a) there were five or more publications that used the same well-defined combination of actions, with very clear description of what they were, without separating the effects of each individual action, and b) the combined set of actions is a commonly used conservation strategy.

  1. Relevant types of comparator

To determine the effectiveness of actions, studies must include a comparison, i.e., monitoring change over time (typically before and after the action was implemented), or for example at treatment and control sites. Alternatively, a study could compare one specific action (or implementation method) against another. For example, this could be comparing a coral reef before and after the closure of an area to bottom trawling or measuring the effectiveness of coral restoration or ‘gardening’ using different types of structures.

Exceptions, which may not have a control but will still be included, are for example the effectiveness of ex-situ coral cultivation.

  1. Relevant types of outcome

Below we provide a list of anticipated metrics; others were included if reported within relevant studies.

  1. Relevant types of study design

The table below lists the study designs included. The strongest evidence comes from randomized, replicated, controlled trials with paired sites and before-and-after monitoring.

Table 1. Study designs

Term

Meaning

Replicated

The action was repeated on more than one individual or site. In conservation and ecology, the number of replicates is much smaller than it would be for medical trials (when thousands of individuals are often tested). If the replicates are sites, pragmatism dictates that between five and ten replicates is a reasonable amount of replication, although more would be preferable. We provide the number of replicates wherever possible. Replicates should reflect the number of times an action has been independently carried out, from the perspective of the study subject. For example, 10 plots within a mown field might be independent replicates from the perspective of plants with limited dispersal, but not independent replicates for larger motile animals such as birds. In the case of translocations/release of captive bred animals, replicates should be sites, not individuals.

Randomized

The action was allocated randomly to individuals or sites. This means that the initial condition of those given the action is less likely to bias the outcome.

Paired sites

Sites are considered in pairs, within which one was treated with the action and the other was not. Pairs, or blocks, of sites are selected with similar environmental conditions, such as water quality or adjacent land use. This approach aims to reduce environmental variation and make it easier to detect a true effect of the action.

Controlled*

Individuals or sites treated with the action are compared with control individuals or sites not treated with the action. (The treatment is usually allocated by the investigators (randomly or not), such that the treatment or control groups/sites could have received the treatment).

Before-and-after

Monitoring of effects was carried out before and after the action was imposed.

Site comparison*

A study that considers the effects of actions by comparing sites that historically had different actions (e.g. action vs no action) or levels of action. Unlike controlled studies, it is not clear how the actions were allocated to sites (i.e. the investigators did not allocate the treatment to some of the sites).

Review

A conventional review of literature. Generally, these have not used an agreed search protocol or quantitative assessment of the evidence.

Systematic review

A systematic review follows structured, predefined methods to comprehensively collate and synthesize existing evidence. It must weigh or evaluate studies, in some way, according to the strength of evidence they offer (e.g. sample size and rigour of design). Environmental systematic reviews are available at: https://www.environmentalevidence.org/index.htm

Study

If none of the above apply, for example a study looking at the number of people that were engaged in an awareness raising project. Or a study measuring change over time in only one site and only after an action.

* Note that ‘controlled’ is mutually exclusive from ‘site comparison’. A comparison cannot be both controlled and a site comparison. However, one study might contain both controlled and site comparison aspects, e.g. study of bycatch by fishers using modified nets (e.g. with a smaller mesh size) and unmodified nets (controlled), and fishers using an alternative net modification, e.g. stiffened nets (site comparison).

Study quality assessment & critical appraisal

We did not quantitatively assess the evidence from each publication or weight it according to quality. However, to allow interpretation of the evidence, we made the size and design of each study we reported clear. We critically appraised each potentially relevant study and excluded those that did not provide data for a comparison to the treatment, did not statistically analyse the results (or if included this was stated in the summary paragraph) or had obvious errors in their design or analysis. A record of the reason for excluding any of the publications was included during screening and kept within the synopsis database.

Data extraction

Data on the effectiveness of the relevant action (e.g. mean species abundance inside or outside a protected area; reduction in bycatch after installation of a bycatch reduction device) was extracted from and summarized for publications that included the relevant subject, types of action, comparator and outcomes outlined above.

In addition to ensuring consistency/accuracy when screening publications for inclusion in the discipline-wide literature database (see above), when authors first began summarizing, the first 10 publications were sent to Conservation Evidence for editing. Further to this, relevant data were extracted by a member of the core Conservation Evidence team for a set of publications as well as the synopsis author to ensure agreement on the correct data and interpretation of the results for inclusion in the synopsis. In addition, summaries were also swapped between authors on a semi-regular basis to quality control the paragraphs that were being written.

Evidence synthesis

  1. Summary protocol

Each publication usually has just one paragraph for each action it tests describing the study in (usually) no more than 150 words using plain English, though more complex studies required longer summaries. Each summary is in the following format:

A [TYPE OF STUDY] in [YEARS X–Y] in [HOW MANY SITES] in/of [HABITAT] in [REGION and COUNTRY] [REFERENCE] found that [ACTION] [SUMMARY OF ALL KEY RESULTS] for [SPECIES/HABITAT TYPE]. [DETAILS OF KEY RESULTS, INCLUDING DATA]. In addition, [EXTRA RESULTS, IMPLEMENTATION OPTIONS, CONFLICTING RESULTS]. The [DETAILS OF EXPERIMENTAL DESIGN, ACTION METHODS and KEY DETAILS OF SITE CONTEXT]. Data were collected in [DETAILS OF SAMPLING METHODS].

Type of study — use terms and order in Table 1.

Site context — for the sake of brevity, only nuances essential to the interpretation of the results are included. The reader is always encouraged to read the original source to get a full understanding of the study site (e.g. history of management, physical conditions, landscape context etc.).

For example:

A replicated, controlled study in 2008–2009 at two coral reef sites near Guana Island, British Virgin Islands (1) found that removing macroalgae from the transplant site for storm-generated fragments of elkhorn Acropora palmata coral led to a higher increase in live tissue growth but no difference in survival compared to fragments transplanted without algae removal. One year after transplanting, the increase in live tissue surface area was higher on fragments where algae had been removed (160%) than fragments transplanted without algae clearance (68%). Survival of fragments after one year did not vary significantly (algae cleared: 52%; algae not cleared: 60% survival). In July – August 2008, a total of 237 storm-generated fragments of elkhorn coral were collected from a coral reef and prepared for transplantation either at the collection site or another site 0.4–3.6 km away. Fragments were attached to the reef substrate, or dead elkhorn coral skeletons, using cable ties, marine epoxy or cement and ensuring live tissue was in contact with the substrate. Once attached, macroalgae was scraped away from a circle of 20 cm radius around 117 of the 237 fragments. Growth (surface area of live tissue) was measured after two and 12 months, and survival was recorded after 12 months using photographs.

  1. Forrester G.E., O’Connell-Rodwell C., Baily, P., Forrester L.M., Giovannini S., Harmon L., Karis R., Krumholz, J., Rodwell T. & Jarecki L. (2011), Evaluating methods for transplanting endangered Elkhorn Corals in the Virgin Islands. Restoration Ecology, 19, 299–306. https://doi.org/10.1111/j.1526-100X.2010.00664.x

A replicated, paired, site comparison study in 2002 of two coastal coral reefs in the Philippines (2) found that establishing a marine reserve closed to fishing resulted in higher density and biomass of species of fish taken by local fishers within the reserve compared to a fished area in one of two cases. For species taken by fishers, density and biomass inside reserve one was higher (density: 68 fish/500 m2; biomass: 89 kg) than outside (27/500 m2; 25 kg), but not significantly different inside and outside reserve two (density inside and outside: 41/500 m2; no biomass data provided). For fish species not subject to fishing, density was higher inside both reserves compared to outside; however, statistical tests showed this was mainly due to habitat variation not protection status (reserve one: 146 fish/250 m2 inside, 113/250 m2 outside; reserve two: 93/250 m2 inside, 32/250 m2 outside). No-take reserves approximately 450 m long (protected for 20 years) and 650 m long (protected for 15 years) off two islands were each compared to fished areas approximately 500 m away. Fish were surveyed in November and December 2002. Divers surveyed fish at six (reserve one) and eight (reserve two) coral reef slope sites inside and outside each reserve. Counts were along 50 × 10 m transects for fish taken by fishers and 50 × 5 m transects for fish not fished. Transects were surveyed twice.

  1. Abesamis R.A., Russ G.A. & Alcala A.C. (2006) Gradients of abundance of fish across no-take marine reserve boundaries: Evidence from Philippine coral reefs. Aquatic Conservation: Marine and Freshwater Ecosystems, 16, 349–371. https://doi.org/10.1002/aqc.730
  1. Terminology used to describe the evidence

Unless specifically stated otherwise, results reflect statistical tests performed on the data, i.e. we only state that there was a difference if it was supported by the statistical test used, and otherwise state that there was no difference or that outcomes were similar. If there was a good reason to report differences between treatments and controls that were not tested for statistical significance, it was made clear within the summary that statistical tests were not carried out. Table 1 above defines the terms used to describe the study designs.

  1. Dealing with multiple actions within a publication

When separate results were provided for the effects of each of the different actions tested, separate summaries were written under each action heading. However, when several actions were carried out at the same time and only the combined effect reported, the result was described with a similar paragraph under all relevant actions. In these circumstances, we clearly communicated within the summary paragraph where multiple actions were used in combination. For example, the first sentence would articulate that a combination of actions was carried out, i.e. ‘...(REF) found that [x action], along with [y] and [z actions] resulted in [describe effects]’.

  1. Dealing with multiple publications reporting the same results and reviews

If two publications described results from the same action implemented in the same space and at the same time, we only included the most stringently peer-reviewed publication (i.e. journal of the highest impact factor). If one included initial results (e.g. after year one) of another (e.g. after 1–3 years), we only included the publication covering the longest time span. If two publications described at least partially different results, we included both but made clear they were from the same project in the paragraph, e.g. ‘A controlled study... (Gallagher et al. 1999; same experimental set-up as Oasis et al. 2001)...’.

  1. Taxonomy

Taxonomy was not updated but follows that used in the original publication. Where possible, common names and scientific names were both given the first time each species was mentioned within each summary.

  1. Key messages

Each action has a set of concise, bulleted key messages at the top, written once all the literature had been summarized. These include information such as the number, design and location of studies included. The first bullet point describes the total number of studies that tested the action and the locations of the studies, followed by key information on the relevant metrics presented under the headings and sub-headings shown below (with number of relevant studies in parentheses for each).

  • X studies examined the effects of [ACTION] on [TARGET POPULATION]. Y studies were in [LOCATION 1]1,2 and Z studies were in [LOCATION 2]3,4.
    • Locations will usually be countries, ordered based on chronological order of studies rather than alphabetically, i.e. ‘the USA1, Australia2’ rather than ‘Australia2, the USA1’. However, when more than 4–5 separate countries, they may be grouped into regions to make it clearer e.g. Europe, North America. The distribution of studies amongst habitat types may also be added here if relevant.

COMMUNITY COMPOSITION (x STUDIES)

  • Richness/diversity (x studies):

POPULATION RESPONSE (x STUDIES)

  • Abundance/Cover (x studies):
  • Reproductive success (x studies):
  • Survival (x studies):
  • Condition (x studies):

OTHER (x STUDIES) (Included only for actions/chapters where relevant)

  • [Sub-heading(s) for the metric(s) reported will be created] (x studies): If no suitable studies were found for an action, the following text was added in place of the key messages above:
  • We found no studies that evaluated the effects of [ACTION] on [TARGET POPULATION].

‘We found no studies’ means that we have not yet found any studies that have directly evaluated this action during our systematic journal and report searches. Therefore, we have no evidence to indicate whether or not the action has any desirable or harmful effects.

  1. Background information

Background information for an action is provided to describe the action and where we feel recent knowledge is required to interpret the evidence. This is presented after the key messages, and relevant references are included in a reference list at the end of the Background section. In some cases, where a body of literature has strong implications for coral conservation, but does not directly test actions for their effects, we may also refer the reader to this literature in the background sections.

Dissemination/communication of evidence synthesis

The information from this evidence synthesis will be available in three ways:

References

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Sutherland W.J., Taylor N.G., MacFarlane D., Amano T., Christie A.P., Dicks L.V., Lemasson A.J., Littlewood N.A., Martin P.A., Ockendon N., Petrovan S.O., Robertson R.J., Rocha R., Shackelford G.E., Smith R.K., Tyler E.H.M. & Wordley C.F.R. (2019) Building a tool to overcome barriers in the research-implementation space: the Conservation Evidence database. Biological Conservation, 238, 108199. https://doi.org/10.1016/j.biocon.2019.108199

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