Skip to main content
  • Systematic Map Protocol
  • Open access
  • Published:

What evidence exists on the ecological and physical effects of built structures in shallow, tropical coral reefs? A systematic map protocol



Shallow, tropical coral reefs face compounding threats from habitat degradation due to coastal development and pollution, impacts from storms and sea-level rise, and pulse disturbances like blast fishing, mining, dredging, and ship groundings that reduce coral reefs’ height and variability. One approach toward restoring coral reef structure from these threats is deploying built structures. Built structures range from engineered modules and repurposed materials to underwater sculptures and intentionally placed natural rocks. Restoration practitioners and coastal managers increasingly consider incorporating built structures, including nature-based solutions, into coral reef-related applications. Yet, synthesized evidence on the ecological and physical performance of built structure interventions across a variety of contexts (e.g., restoration, coastal protection, mitigation, tourism) is not readily available to guide decisions. To help inform management decisions, here we aim to document the global evidence base on the ecological and physical performance of built structures in shallow (≤ 30 m) tropical (35° N to 35° S latitude) coral ecosystems. The collated evidence base on use cases and associated ecological and physical outcomes of built structure interventions can help inform future consideration of built structures in reef restoration design, siting, and implementation.


To discover evidence on the performance of built structures in coral reef-related applications, such as restoration, mitigation, and coastal protection, primary literature will be searched across indexing platforms, bibliographic databases, open discovery citation indexes, a web-based search engine, a novel literature discovery tool, and organizational websites. The geographic scope of the search is global, and there is no limitation to temporal scope. Primary literature will be screened first at the level of title and abstract and then at the full text level against defined eligibility criteria for the population, intervention, study type, and outcomes of interest. Metadata will be extracted from studies that pass both screening levels. The resulting data will be analyzed to determine the distribution and abundance of evidence. Results will be made publicly available and reported in a systematic map that includes a narrative description, identifies evidence clusters and gaps, and outlines future research directions on the use of built structures in coral reef-related applications.


Coral reefs provide extensive ecosystem services, including biodiversity benefits, coastal protection, and fisheries provisioning [53], yet face global declines from multiple threats [15, 28]. Local threats include those from habitat degradation often linked to coastal development [24], overfishing [54], and pollution [32, 34, 55], as well as from disturbances like blast fishing [52], coral mining [10], dredging [17], and ship groundings [37]. Global stressors from climate change include mortality from ocean warming and associated bleaching [29], disease [27], and ocean acidification [12]. Climate change is also increasing the severity and frequency of storms that can further degrade coral reefs by breaking and dislodging coral [18] and increasing sedimentation, which reduces the potential for successful coral recruitment [16, 47].

Strategies to slow or reverse declines in coral reefs often include restoration, such as direct transplantation of corals or larval enhancement [5]. Coastal managers and restoration practitioners are considering the incorporation of built structures into coral restoration design and implementation [50]. Here, we define built structures as those that have been engineered, designed, created, built, or constructed using artificial, hybrid, or natural materials. We define restoration broadly, following the UN Decade on Ecosystem Restoration, as “efforts to prevent, halt, or reverse the degradation of ecosystems” [48]. For coral reefs, this definition includes partial or holistic ecosystem recovery and thus actions aimed towards returning reefs to a historical state or creating new reefs [49, 50]. Built structures have a centuries-long history of being deployed in the seascape for multiple objectives. For example, artificial reefs have been purposely sunk since the 1600 s [44] to increase fishing yield, provide recreation opportunities, and conduct scientific research experiments, but in select cases have also been used expressly to restore coral reefs by creating, replacing, supplementing, enhancing, or stabilizing structured habitat [4, 25]. These intentionally deployed structures include those that have been repurposed from their original uses (e.g., concrete pipes originally used in construction), as well as modules designed for particular contexts, such as reef restoration (e.g., target species, environmental settings) [31, 43]. In the past decade, underwater artwork installations have grown in popularity, as artwork and sculpture gardens have been commissioned and implemented to help restore corals and generate locations for recreational divers to enjoy [3, 41] (1000 Mermaids Artificial Reef Project,

Built structures have also been used for environmental mitigation and coastal protection purposes. Structures installed for environmental mitigation seek to address impacts from disturbances like blast fishing, ship grounding, coral mining, dredging, and storms, which can reduce reef height and complexity and create excess amounts of rubble that prevent survival of coral recruits [8, 51]. In these instances, deployment of natural rock, hybrid structures (e.g., rock with cement, rock with mesh net), or human-made structures (e.g., concrete) can help stabilize rubble and allow for recruit survival [8]. The role of coral reefs in providing coastal protection benefits has become increasingly apparent as coral reefs can reduce wave energy by ~ 97% where present [19] and thus provide ~ $1.8 billion in hazard risk reduction benefits per year in the U.S. alone [39]. In response to the risk reduction benefits, new initiatives have been launched to design engineered reefs for coastal protection. In Grenada, for example, modular engineered structures were deployed to help reduce coastal erosion and flooding [38], while in southeast India, trapezoidal artificial modules were deployed to dissipate wave energy [30]. Newly funded Department of Defense projects in the U.S. aim to create hybrid reef structures that incorporate some “gray” engineering (e.g., traditional hardened structures) and some “green” (e.g., natural components and nature-based solutions) ecological objectives to mitigate flooding, erosion, and storm damage (Reefense,

Despite the history and increasing consideration of built structures for coral restoration and related applications like environmental mitigation and coastal protection, questions remain regarding how built structures should be considered in management and restoration decisions. Central to these questions is that the global evidence base regarding the use and performance of built structures has not been collated or synthesized; but, see syntheses for particular contexts, such as artificial reefs [25], substrate stabilization [8], and 3D technology for reef structures [33]. The lack of broadly synthesized evidence presents barriers to implementing management and policy decisions regarding future use of built structures in coral reef systems. Without synthesized evidence, it is challenging for decision makers to rigorously and reproducibly evaluate whether built structures may be appropriate tools in particular environmental settings and use-case scenarios.

The goal of this study is to collate evidence on the ecological and physical performance of built structure interventions in shallow, tropical coral reef settings. This synthesis of knowledge will help inform practice for built structure design and implementation, including as nature-based solutions that can help address societal and ecological challenges. Because built structures have been used for multiple applications related to tropical coral reefs, such as for restoration, coastal protection and environmental mitigation, we will include evidence from these diverse bodies of literature. This will ensure that our synthesis stems from the most comprehensive body of relevant literature and will also help ensure that findings from our synthesis can be used to help guide management decisions regarding the design, siting, and implementation of gray-green infrastructure in coral reef settings.

Stakeholder engagement

This project was jointly conceptualized by scientists from the National Oceanic and Atmospheric Administration (NOAA) National Centers for Coastal Ocean Science (NCCOS), the U.S. Army Corps of Engineers (USACE) Engineering with Nature (EWN) Program, and the U.S. Geological Survey (USGS) Coastal and Marine Hazards and Resources Program (CMHRP) to synthesize how built structures have been used in a variety of contexts, such as those related to coral restoration, coastal protection, and environmental mitigation. The motivation for the synthesis was to catalog uses of and ecological and physical performance outcomes associated with built structures in shallow, tropical coral reef settings to help inform hybrid or gray-green reef structure design, siting, implementation, and potentially policy decisions. The core team of scientists from NOAA, USACE, and USGS scoped the systematic map and developed the search strategy based on stakeholder needs. Because the core team does not include international scientists, additional stakeholders will be consulted during the development of the systematic map to help ensure that primary literature from international sources is captured by the systematic map.

Objective of the systematic map

The objective of this systematic map is to document the global evidence base on the performance (ecological and physical) of built structures in shallow, tropical coral reef settings. The systematic map also aims to summarize how evidence differs by built structure qualities, such as the type and material of intervention, as well as the goal and seascape setting.

Question: What is the distribution and abundance of evidence on the ecological and physical performance of built structures in shallow, tropical coral reef systems?


  • How does the distribution and abundance of evidence on the performance of built structures used in coral reef-related applications differ by intervention type (e.g., human-made—designed or engineered structures, human-made repurposed structures, human-made artwork, hybrid structures of artificial and natural origin, and natural structures of geologic origin)?

  • For which types (e.g., reef modules, concrete pipes, natural rock, mesh over rubble) and materials (e.g., concrete, metal, rock, fiberglass) of built structures has the performance been evaluated?

  • For which ecological and physical outcomes has the performance of built structures used in coral reef-related applications been evaluated?

  • How does the distribution and abundance of evidence on built structures differ by intervention goal or context (e.g., restoration, environmental mitigation, coastal protection, tourism), seascape setting (e.g., depth, energetic environment, relative location on reef), spatial scale, and geographic region?

Elements of the primary question: Elements of the primary question are the population, intervention, comparator, outcome, and study type (Table 1).

Table 1 Summary of elements of the primary question, including population, intervention, comparator, outcome, and study type


The systematic map will follow evidence synthesis standards from the Collaboration for Environmental Evidence [11] and will use the RepOrting standards for Systematic Evidence Synthesis (ROSES) [22] (Additional file 1).

Search strategy

A search for primary literature, including peer-reviewed articles and gray literature will be performed using multiple indexing platforms, bibliographic databases, organizational websites, and other search platforms. There are no temporal constraints on the search. The geographic scope for the search is global because coral reef degradation and loss is a global issue [15]. Searches will be performed in English, and articles without a full text published in English will be documented and excluded. We made the decision to restrict the search to English language due to resource constraints and recognize that this introduces bias to the systematic map. Here, we describe details of the search strategy, including the search string development and literature search plan.

Search string development

The core team for the systematic map developed a list of keywords corresponding to the elements of the primary question (Table 1) for coral reefs (population), built structures (intervention), and both ecological and physical outcomes (outcomes) (Additional file 2). Search terms were combined into search strings (Table 2) and tested in Web of Science (Additional file 2). We developed five substrings, one of which narrowed the search to coral reefs. We originally tested the inclusion of the word reef* in the coral substring (coral* AND reef*), but multiple known articles that included relevant evidence did not mention the word reef in the title or abstract, so we retained only the word coral* in that substring. Two substrings describe the built structures and their context for use (intervention). Two additional substrings detail ecological and physical outcomes associated with the intervention.

Table 2 Search substrings created for population, interventions, and outcomes (PIO)

The six search substrings will be combined into one search string as follows:

Population: (coral reef substring)


Intervention: (built structure substring AND context for built structure intervention substring)


Outcome: (ecological outcome substring OR physical outcome substring)

The combined search string will be used to search titles and abstracts. More specifically, search results will be those where search string terms appear in the title, in the abstract, or in both the title and abstract (e.g., search syntax will be title OR abstract).).

Searching the literature

Searches for relevant primary literature will be performed in indexing platforms, bibliographic databases, open discovery citation indexes, and a web-based search engine (Table 3). Search strings were originally developed using Web of Science search syntax thus will be modified as needed to meet syntax requirements of other indexing platforms and bibliographic databases. The web-engine search will be performed using Google Scholar via Harzing’s Publish or Perish Software [23]. The search string used for Google Scholar will be adapted to meet syntax limitations of the platform, will be performed on title only, and will be restricted to the first 1000 results [21]. Searches will also be performed using Inciteful (, a novel literature discovery tool, for up to the first 1000 similar results [57]. Specifically, the search will be seeded with benchmarking articles; no search string is required for Inciteful.

Table 3 List of sources to be searched for relevant primary literature

Twenty organizational websites will also be searched for evidence (Table 4). The organizations span government agencies, nonprofit organizations, and other entities that report on the use of built structures in coral reef ecosystems. Most organizational websites do not permit Boolean searches, so search strings will be by hand and details of how searches were implemented will be documented. Gray literature will be screened in situ, and up to 100 results per organizational website will be screened.

Table 4 Names of organizational websites to be searched for evidence

Comprehensiveness of the search

The evidence synthesis team identified 21 benchmarking articles to test against the search string (Additional file 3). These benchmarking articles were sourced from subject matter experts, including those from the core research team. Search strings were tested in Web of Science, and 18 of the 21 articles were indexed in Web of Science (e.g., 3 articles were not indexed in Web of Science meaning that they are not part of the Web of Science collection and so will not be found in Web of Science regardless of the search string used). Search strings were adjusted incrementally until all but two of the 18 indexed articles were identified. The two articles that were unable to be identified in Web of Science did not include terms related to the intervention in the title or abstract. These articles had been provided by the synthesis team because they had case studies embedded within that used built structures but were deemed undetectable in the search since the intervention was not covered in the title and abstract.

Reference management and deduplication

Reference management will be conducted using Clarviate’s EndNote (version 20) citation management software [46]. RIS files from searches implemented on different platforms (e.g., indexing platforms, bibliographic databases) will be uploaded separately to EndNote and references deduplicated using built-in EndNote functions and open-source tools, such as the R package ‘CiteSource’ [40]. Reference metadata will be checked and fixed as needed. Cleaned references will be combined into one.RIS file and uploaded to the title and abstract screening software, Swift-Active Screener (Sciome LLC; [26], for review. Following review of title and abstracts, updated.RIS files of included and excluded articles will be exported from the screening software. The .RIS file corresponding to articles that passed title and abstract screening will then be imported to EndNote for full text screening. Screeners will use EndNote to review references during full text screening and will track reference inclusion and conduct metadata coding using Google spreadsheets. RIS records of included and excluded articles will be kept for ROSES reporting.

Article screening and study eligibility criteria

Screening process

Articles returned from literature searches will be screened against eligibility criteria in two stages, first by title and abstract and second by full text (Table 5). The software Swift-Active Screener will be used for title and abstract screening because it utilizes a combination of screener feedback and a type of machine learning termed active learning [26]. The active learning algorithm incorporates screener feedback on which articles are deemed relevant or irrelevant. Specifically, the algorithm ranks and shuffles unscreened articles so that articles it designates as relevant can be prioritized for screening. Screening will occur until the software’s “recall rate” reaches 95% [26]. The “recall rate” is the running estimate of the percentage of relevant references that have been screened from the original set. Previous studies have demonstrated that Swift Active Screener, with its active learning algorithm and ranking system, can provide significant time resource savings. Use of Swift Active Screener is growing within environmental sciences [56] and is accepted in medical sciences [13, 20]. Using Swift Active Screener may introduce some bias into the systematic map if articles are overlooked as a product of the algorithm and ranking system; however, we expect ~ 20,000 results, making the use of Swift Active Screener necessary and helpful. Keywords will be highlighted in Swift to help identify information relevant for assessing eligibility criteria. Screeners will indicate in Swift whether articles should be included or excluded based on the eligibility criteria. Articles that pass title and abstract screening will be screened at the full text stage to determine whether they still meet eligibility criteria and should be included in the study or not. If the full text for an article cannot be located, the article will be excluded. Exclusion rationale will be documented during both screening stages.

Table 5 Preliminary eligibility criteria for literature on built structures used for coral restoration

Screeners will be trained on how to reproducibly conduct both screening stages. Training will occur in dedicated training sessions where select articles are screened as a group before select additional articles are screened individually. Inconsistencies in screening decisions will be discussed and used to refine eligibility criteria. Once screeners are trained, quantitative assessments of inter-reviewer consistency will be conducted by generating Kappa statistics or percentage agreement values for all pairs of reviewers for a set of 100 randomly selected titles and abstracts. Double screening will be conducted for up to 5% of the title and abstract or full text screening stages. Single screening may introduce bias into the systematic map, but because of resource constraints and the high number of expected articles (~ 20,000), it is necessary. With the expected number of articles, 5% would be ~ 1000 articles. Screeners cannot screen articles for which they were an author or coauthor.

Eligibility criteria

Eligibility criteria include the population of subjects, intervention, comparator, outcome, and study type (Table 5).

Relevant population(s)

The relevant population for this systematic map is coral reefs located in nearshore, shallow tropical waters. We define shallow as ≤ 30 m. We define tropical waters as those between 35° N and 35° S latitude; this may include some water typically designated as subtropical depending on the latitudinal classification scheme. Reef types may include barrier reefs, reef flats, fringing reefs, reef crests, patch reefs, reef complexes, bommies, or atolls, as well as locations like forereef and backreef. If a coral reef is created by a built structure intervention (e.g., built structure led to (or was intended for) coral reef creation on a former soft sedimentary seascape, such as one composed of carbonate sand), then it is also eligible for inclusion. Coral reefs located in deep waters or mesophotic zones are excluded. Reefs with substrate other than carbonate deposited by coral, such as rocky reefs or sponge reefs, are also excluded. All other marine, coastal, terrestrial, freshwater, and subterranean ecosystems are also excluded.

Relevant intervention(s)

Interventions of interest for the systematic map are those that establish built structures in shallow, tropical coral reef settings (Table 6). Here, we define built structures as those that have been engineered, designed, created, built, or constructed using artificial, hybrid, or natural materials. Structures that use a combination of artificial and natural materials, classified as hybrid, are included. Structures such as natural rock or boulders are also included, so long as they are used as part of an intentional, active intervention because using mined rock or other naturally sourced boulders, rubble, or rock can be conducted in mitigation and restoration contexts. Eligible structures span a spectrum of those that were intentionally designed using cutting edge technologies (i.e., 3D printing) and engineering processes (design analyses for performance and design optimization), those designed using simpler approaches such as concrete castings, those that were created as artwork (i.e., underwater sculptures), and those that were repurposed for reef systems (i.e., natural rocks, repurposed concrete). Built structures must have been placed in nearshore, shallow environments suitable for coral reefs and may include those with varied goals. For example, goals or the context of the built structure intervention may include reef creation, enhancement, remediation, rehabilitation, or stabilization, including to address impacts like ship grounding, blast fishing, coral mining, dredging, storm damage, bleaching events, invasive species, or other damages. Goals can also include offsetting damages to coral reefs in other areas or more simply testing the effectiveness of built structures for coral restoration, as well as tourism and recreation or research related goals.

Table 6 Typology of built structures interventions.

Relevant comparator(s)

No comparator is necessary for an article to be eligible. It must only contain the intervention. If a study does include a comparator, though, it is eligible, and the comparator type will be recorded. Potential comparators include locations with built structures versus without; before, during, or after built structure intervention; different types of built structure interventions.

Relevant outcome(s)

Outcomes from built structure interventions in coral reef settings include ecological and physical performance categories. Specific typologies were developed to characterize these ecological and physical performance outcomes (Tables 7; 8;). Briefly, ecological performance categories relate specifically to coral and coral reef metrics, such as recruitment, growth, morality, condition, rugosity, and cover (Table 7). Ecological metrics related to biological interactions with coral are included, but outcomes solely related to other trophic groups, such as other non-coral invertebrates, macroalgae, and fish are not the focus of the systematic map thus are excluded. Broader ecosystem-level metrics or processes, such as productivity, pollution, and nutrient cycling are also outside the scope of this systematic map. Physical performance categories of interest relate to waves, currents, erosion, flooding, and other coastal processes related to coastal protection and coastal resilience (Table 8). Chemical, social, and economic outcomes are beyond the scope of the map.

Table 7 Typology of ecological performance outcomes.
Table 8 Typology of physical performance outcomes.

Relevant study type(s)

Studies that report quantitative data from observational, experimental, quasi-experimental, modeling, or simulation studies are included. Studies conducted in situ (field) or ex situ (lab, flume, etc.) or in computing environments (modeling, simulation) will be included. If studies are reviews, meta-analyses, theoretical, opinions, perspectives, or commentaries, they are ineligible because they do not report quantitative findings.

Study validity assessment

Study validity will not be systematically assessed because this is a systematic map which aims to collate and summarize the distribution and abundance of evidence. During data coding, attributes will be extracted that can be used for follow-up assessments of study validity for subsets of the evidence base.

Data extraction and coding strategy

Metadata attributes from studies that adhere to eligibility criteria will be entered into a data “coding” spreadsheet (Table 9; Additional file 4). The attributes will include bibliographic information, as well as those related to the population, intervention, study type, comparator, and outcome. For example, intervention attributes will include the type of built structure intervention (Table 6), the structure material, proprietary name (if applicable), policy-relevant term, and description of the coral restoration context. Details on each metadata attribute are provided in a code book adapted from a code book used in [56] . The code book provides a description of each attribute, instructions for data entry, and levels of categorical attributes that screeners can select from dropdown menus. We do not plan to contact authors to request missing information. Rather, if the required information is not stated in the article, it will be coded as “unknown.” If an attribute is not applicable to an article, the attribute will be coded as “not applicable.”

Table 9 Metadata attributes planned for extraction during data coding

Screeners will be trained to code metadata reproducibility during a training session. The training session will focus on collectively coding data for several articles. Each screener will then be assigned a subset of articles to code independently. Coding results will be compared qualitatively and the group will discuss inconsistencies and alter attributes and instructions if necessary. Double data extraction, which is the extraction of data from a study by multiple screeners, will not be conducted because of the high number of anticipated articles that will require data coding. Instead, we will conduct spot checks for a percentage of articles. The percentage of articles that we spot check in the systematic map will be reported.

Study mapping and presentation

Metadata from studies that meet eligibility criteria at both the title and abstract and full text screening stages will be analyzed to identify patterns in the distribution and abundance of evidence related to the use of built structures in coral restoration and related applications. Analyses will be conducted in R [36] to answer the posed primary and secondary research questions, characterize the evidence base, and identify both evidence clusters and evidence gaps. Specifically, the extent of evidence on different types of built structure interventions by their typology (Table 6), material, proprietary name, and policy relevant term will be characterized. Similarities and differences in the evidence base according to the context that the built structure intervention was intended, such as coral restoration, environmental mitigation, and coastal protection, will be identified. The abundance and distribution of evidence across ecological and physical outcomes for which built structures have been evaluated, as well as for study setting—geographic region, spatial scale, and seascape environment—will be cataloged. When feasible, the directionality of evidence (e.g., positive, negative, neutral) will be documented. Evidence clusters and gaps will be identified with heat maps displaying the number of studies corresponding to cross-tabulated attributes.

Findings will be compiled into an evidence map for peer-reviewed publication that will include a narrative summary of the evidence base. This state of the science review will be complemented by visual depictions of the evidence base using heat maps, bar plots, and geographic distribution maps. Tabular summaries of findings may also be included. The systematic map will emphasize the discovery of evidence clusters and gaps, and suggest potential avenues for future research. Map findings may be applied to help improve practice and help inform policy and management decisions regarding the potential use of built structures in tropical, shallow coral reefs. Map findings will also inform systematic reviews on the quantitative effectiveness of built structures. All data on included and excluded literature and associated metadata will be made publicly available.

Availability of data and materials

Not applicable.


  1. Barbier EB, Hacker SD, Kennedy C, Koch EW, Stier AC, Silliman BR. The value of estuarine and coastal ecosystem services. Ecol Monogr. 2011;81:169–93.

    Google Scholar 

  2. Bayraktarov E, Stewart-Sinclair PJ, Brisbane S, Boström-Einarsson L, Saunders MI, Lovelock CE, Possingham HP, Mumby PJ, Wilson KA. Motivations, success, and cost of coral reef restoration. Restor Ecol. 2019;27:981–91.

    Google Scholar 

  3. Beans C. Science and culture: artistic endeavors strive to save coral reefs. Proc Natl Acad Sci. 2018;115:5303–5.

    CAS  Google Scholar 

  4. Becker A, Taylor MD, Folpp H, Lowry MB. Managing the development of artificial reef systems: the need for quantitative goals. Fish Fish. 2018;19:740–52.

    Google Scholar 

  5. Bostrom-Einarsson L, Babcock RC, Bayraktarov E, Ceccarelli D, Cook N, Ferse SCA, Hancock B, Harrison P, Hein M, Shaver E, Smith A, Suggett D, Stewart-Sinclair PJ, Vardi T, McLeod IM. Coral restoration—a systematic review of current methods, successes, failures and future directions. PLoS ONE. 2020;15: e0226631.

    CAS  Google Scholar 

  6. Bridges T, King J, Simm J, Beck M, Collins G, Lodder Q, Mohan R. International guidelines on natural and nature-based features for flood risk management. In: U.S. Army Engineer Research and Development Center, editor. U.S. Army Corps of Engineers; 2021.

  7. Brooks WR, Rudd ME, Cheng SH, Silliman BR, Gill DA, Ahmadia GN, Andradi-Brown DA, Glew L, Campbell LM. Social and ecological outcomes of conservation interventions in tropical coastal marine ecosystems: a systematic map protocol. Environ Evid. 2020;9:1–12.

    Google Scholar 

  8. Ceccarelli DM, McLeod IM, Bostrom-Einarsson L, Bryan SE, Chartrand KM, Emslie MJ, Gibbs MT, Gonzalez Rivero M, Hein MY, Heyward A, Kenyon TM, Lewis BM, Mattocks N, Newlands M, Schlappy ML, Suggett DJ, Bay LK. Substrate stabilisation and small structures in coral restoration: state of knowledge, and considerations for management and implementation. PLoS ONE. 2020;15: e0240846.

    CAS  Google Scholar 

  9. Cheng SH, Costedoat S, Sterling EJ, Chamberlain C, Jagadish A, Lichtenthal P, Nowakowski AJ, Taylor A, Tinsman J, Canty SWJ, Holland MB, Jones KW, Mills M, Morales-Hidalgo D, Sprenkle-Hyppolite S, Wiggins M, Mascia MB, Munoz Brenes CL. What evidence exists on the links between natural climate solutions and climate change mitigation outcomes in subtropical and tropical terrestrial regions? A systematic map protocol. Environ Evid. 2022;11:1–17.

    Google Scholar 

  10. Clark S, Edwards AJ. Use of artificial reef structures to rehabilitate reef flats degraded by coral mining in the Maldives. Bull Mar Sci. 1994;55:724–44.

    Google Scholar 

  11. Collaboration for Environmental Evidence. Guidelines and standards for evidence synthesis in environmental management. Version 5.1. In: Pullin AS, Frampton GK, Livoreil B, Petrokofsky G, editors; 2022.

  12. Cornwall CE, Comeau S, Kornder NA, Perry CT, van Hooidonk R, DeCarlo TM, Pratchett MS, Anderson KD, Browne N, Carpenter R, Diaz-Pulido G, D’Olivo JP, Doo SS, Figueiredo J, Fortunato SAV, Kennedy E, Lantz CA, McCulloch MT, Gonzalez-Rivero M, Schoepf V, Smithers SG, Lowe RJ. Global declines in coral reef calcium carbonate production under ocean acidification and warming. Proc Natl Acad Sci. 2021;118: e2015265118.

    CAS  Google Scholar 

  13. DeLuca NM, Angrish M, Wilkins A, Thayer K, Cohen Hubal EA. Human exposure pathways to poly- and perfluoroalkyl substances (PFAS) from indoor media: a systematic review protocol. Environ Int. 2021;146: 106308.

    CAS  Google Scholar 

  14. Douglass, S. L., and B. A. Webb. 2020. Highways in the coastal environment. U.S. Department of Transportation, Federal Highway Administration. Publication No. FHWA-HIF-19–059. 436 pp.

  15. Eddy TD, Lam VWY, Reygondeau G, Cisneros-Montemayor AM, Greer K, Palomares MLD, Bruno JF, Ota Y, Cheung WWL. Global decline in capacity of coral reefs to provide ecosystem services. One Earth. 2021;4:1278–85.

    Google Scholar 

  16. Edmunds PJ, Gray SC. The effects of storms, heavy rain, and sedimentation on the shallow coral reefs of St. John, US Virgin Islands. Hydrobiologia. 2014;734:143–58.

    CAS  Google Scholar 

  17. Erftemeijer PL, Riegl B, Hoeksema BW, Todd PA. Environmental impacts of dredging and other sediment disturbances on corals: a review. Mar Pollut Bull. 2012;64:1737–65.

    CAS  Google Scholar 

  18. Fabricius KE, De’ath G, Puotinen ML, Done T, Cooper TF, Burgess SC. Disturbance gradients on inshore and offshore coral reefs caused by a severe tropical cyclone. Limnol Oceanogr. 2008;53:690–704.

    Google Scholar 

  19. Ferrario F, Beck MW, Storlazzi CD, Micheli F, Shepard CC, Airoldi L. The effectiveness of coral reefs for coastal hazard risk reduction and adaptation. Nat Commun. 2014;5:3794.

    CAS  Google Scholar 

  20. Gardner B, Betson M, Cabal Rosel A, Canica M, Chambers MA, Contadini FM, Gonzalez Villeta LC, Hassan MM, La Ragione RM, de Menezes A, Messina D, Nichols G, Olivenca DV, Phalkey R, Prada JM, Ruppitsch W, Santorelli LA, Selemetas N, Tharmakulasingam M, M. v. V. AH, M. Woegerbauer, I. Deza-Cruz, and G. Lo Iacono. Mapping the evidence of the effects of environmental factors on the prevalence of antibiotic resistance in the non-built environment: protocol for a systematic evidence map. Environ Int. 2023;171: 107707.

    Google Scholar 

  21. Haddaway NR, Collins AM, Coughlin D, Kirk S. The role of Google Scholar in evidence reviews and its applicability to grey literature searching. PLoS ONE. 2015;10: e0138237.

    Google Scholar 

  22. Haddaway NR, Macura B, Whaley P, Pullin AS. ROSES RepOrting standards for Systematic Evidence Syntheses: pro forma, flow-diagram and descriptive summary of the plan and conduct of environmental systematic reviews and systematic maps. Environ Evid. 2018;7:1–8.

    Google Scholar 

  23. Harzing AW. Publish or perish; 2007.

  24. Heery EC, Hoeksema BW, Browne NK, Reimer JD, Ang PO, Huang D, Friess DA, Chou LM, Loke LHL, Saksena-Taylor P, Alsagoff N, Yeemin T, Sutthacheep M, Vo ST, Bos AR, Gumanao GS, Syed Hussein MA, Waheed Z, Lane DJW, Johan O, Kunzmann A, Jompa J, Suharsono D, Taira AG, Bauman, and P. A. Todd. Urban coral reefs: Degradation and resilience of hard coral assemblages in coastal cities of East and Southeast Asia. Mar Pollut Bull. 2018;135:654–81.

    CAS  Google Scholar 

  25. Higgins E, Metaxas A, Scheibling RE. A systematic review of artificial reefs as platforms for coral reef research and conservation. PLoS ONE. 2022;17: e0261964.

    CAS  Google Scholar 

  26. Howard BE, Phillips J, Tandon A, Maharana A, Elmore R, Mav D, Sedykh A, Thayer K, Merrick BA, Walker V, Rooney A, Shah RR. SWIFT-active screener: accelerated document screening through active learning and integrated recall estimation. Environ Int. 2020;138: 105623.

    Google Scholar 

  27. Howells EJ, Vaughan GO, Work TM, Burt JA, Abrego D. Annual outbreaks of coral disease coincide with extreme seasonal warming. Coral Reefs. 2020;39:771–81.

    Google Scholar 

  28. Hughes TP, Barnes ML, Bellwood DR, Cinner JE, Cumming GS, Jackson JBC, Kleypas J, van de Leemput IA, Lough JM, Morrison TH, Palumbi SR, van Nes EH, Scheffer M. Coral reefs in the Anthropocene. Nature. 2017;546:82–90.

    CAS  Google Scholar 

  29. Hughes TP, Kerry JT, Alvarez-Noriega M, Alvarez-Romero JG, Anderson KD, Baird AH, Babcock RC, Beger M, Bellwood DR, Berkelmans R, Bridge TC, Butler IR, Byrne M, Cantin NE, Comeau S, Connolly SR, Cumming GS, Dalton SJ, Diaz-Pulido G, Eakin CM, Figueira WF, Gilmour JP, Harrison HB, Heron SF, Hoey AS, Hobbs JA, Hoogenboom MO, Kennedy EV, Kuo CY, Lough JM, Lowe RJ, Liu G, McCulloch MT, Malcolm HA, McWilliam MJ, Pandolfi JM, Pears RJ, Pratchett MS, Schoepf V, Simpson T, Skirving WJ, Sommer B, Torda G, Wachenfeld DR, Willis BL, Wilson SK. Global warming and recurrent mass bleaching of corals. Nature. 2017;543:373–7.

    CAS  Google Scholar 

  30. Jayanthi M, Patterson Edward JK, Malleshappa H, N. Gladwin GnanaAsir, G. Mathews, K. Diraviya Raj, D. S. Bilgi, T. K. Ashok Kumar, and S. A. Sannasiraj. Perforated trapezoidal artificial reefs can augment the benefits of restoration of an island and its marine ecosystem. Restor Ecol. 2019;28:233–43.

    Google Scholar 

  31. Keenan SF, Switzer TS, Knapp A, Weather EJ, Davis J. Spatial dynamics of the quantity and diversity of natural and artificial hard bottom habitats in the eastern Gulf of Mexico. Continental Shelf Res. 2022;233:104633.

    Google Scholar 

  32. Lapointe BE, Brewton RA, Herren LW, Porter JW, Hu C. Nitrogen enrichment, altered stoichiometry, and coral reef decline at Looe Key, Florida Keys, USA: a 3-decade study. Mar Biol. 2019;166:108.

    Google Scholar 

  33. Levy N, Berman O, Yuval M, Loya Y, Treibitz T, Tarazi E, Levy O. Emerging 3D technologies for future reformation of coral reefs: enhancing biodiversity using biomimetic structures based on designs by nature. Sci Total Environ. 2022;830: 154749.

    CAS  Google Scholar 

  34. Nalley EM, Tuttle LJ, Barkman AL, Conklin EE, Wulstein DM, Richmond RH, Donahue MJ. Water quality thresholds for coastal contaminant impacts on corals: a systematic review and meta-analysis. Sci Total Environ. 2021;794: 148632.

    CAS  Google Scholar 

  35. Ouédraogo D-Y, Delaunay M, Sordello R, Hédouin L, Castelin M, Perceval O, Domart-Coulon I, Burga K, Ferrier-Pagès C, Multon R, Guillaume MMM, Léger C, Calvayrac C, Joannot P, Reyjol Y. Evidence on the impacts of chemicals arising from human activity on tropical reef-building corals; a systematic map. Environ Evid. 2021;10:1–18.

    Google Scholar 

  36. Paxton AB, Riley TN, Steenrod CL, Smith CS, Zhang YS, Gittman RK, Silliman BR, Buckel CA, Viehman TS, Puckett BJ, Davis J. What evidence exists on the performance of nature-based solutions interventions for coastal protection in biogenic, shallow ecosystems? A systematic map protocol. Environmental Evidence. 2023;12(1):1–25.

  37. R Development Core Team. R: a language and environment for statistical computing. Vienna: R Foundation for Statistical Computing; 2022.

    Google Scholar 

  38. Raymundo LJ, Licuanan WY, Kerr AM. Adding insult to injury: ship groundings are associated with coral disease in a pristine reef. PLoS ONE. 2018;13: e0202939.

    CAS  Google Scholar 

  39. Reguero BG, Beck MW, Agostini VN, Kramer P, Hancock B. Coral reefs for coastal protection: a new methodological approach and engineering case study in Grenada. J Environ Manage. 2018;210:146–61.

    Google Scholar 

  40. Reguero BG, Storlazzi CD, Gibbs AE, Shope JB, Cole AD, Cumming KA, Beck MW. The value of US coral reefs for flood risk reduction. Nat Sustain. 2021;4:688–98.

    Google Scholar 

  41. Riley T, Hair K, Wallrich L, Grainger M, Young S, Pritchard C, Haddaway N. CiteSource: analyze the utility of information sources and retrieval methodologies for evidence synthesis; 2022.

  42. Smith A, Songcuan AJ, Cook N, Brown R, Cook K, Richardson R. Engineering, ecological and social monitoring of the largest underwater sculpture in the world at John Brewer Reef, Australia. J Mar Sci Eng. 2022;10:1617.

    Google Scholar 

  43. Smith CS, Rudd ME, Gittman RK, Melvin EC, Patterson VS, Renzi JJ, Wellman EH, Silliman BR. Coming to terms with living shorelines: a scoping review of novel restoration strategies for shoreline protection. Front Mar Sci. 2020;7:434.

    Google Scholar 

  44. Steward DAN, Paxton AB, Bacheler NM, Schobernd CM, Mille K, Renchen J, Harrison Z, Byrum J, Martore R, Brinton C, Riley KL, Taylor JC, Kellison GT. Quantifying spatial extents of artificial versus natural reefs in the seascape. Front Mar Sci. 2022;9:980384.

    Google Scholar 

  45. Stone RB, McGurrin JM, Sprague LM, Seaman WJ. Artificial habitats of the world: synopsis and major trends. In: Seaman WJ, Sprague LM, editors. Artificial habitats for marine and freshwater fisheries. Academic Press; 1991. p. 31–60.

    Google Scholar 

  46. Temmerman S, Horstman EM, Krauss KW, Mullarney JC, Pelckmans I, Schoutens K. Marshes and mangroves as nature-based coastal storm buffers. Annu Rev Mar Sci. 2022;15:95–118.

  47. The EndNote Team. EndNote. Philadelphia: Clarivate; 2020.

    Google Scholar 

  48. Tuttle LJ, Donahue MJ. Effects of sediment exposure on corals: a systematic review of experimental studies. Environ Evid. 2022;11:4.

    Google Scholar 

  49. United Nations General Assembly. Resolution Adopted by the General Assembly on 1 March 2019. A/RES/73/284, United Nations Decade on Ecosystem Restoration (2021–2039); 2019.

  50. Vardi T, Hoot WC, Levy J, Shaver E, Winters RS, Banaszak AT, Baums IB, Chamberland VF, Cook N, Gulko D, Hein MY, Kaufman L, Loewe M, Lundgren P, Lustic C, MacGowan P, Matz MV, McGonigle M, McLeod I, Moore J, Moore T, Pivard S, Pollock FJ, Rinkevich B, Suggett DJ, Suleiman S, Viehman TS, Villalobos T, Weis VM, Wolke C, Montoya-Maya PH. Six priorities to advance the science and practice of coral reef restoration worldwide. Restor Ecol. 2021;29: e13498.

    Google Scholar 

  51. Viehman T, Reguero B, Lenihan H, Rosman J, Storlazzi C, Goergen E, Canals Silander M, Groves S, Holstein D, Bruckner A, Carrick J, Haus B, Royster J, Duvall M, Torres W, Hench J. Coral restoration for coastal resilience: integrating ecology, hydrodynamics, and engineering at multiple scales. Ecosphere. 2023;14: e4517.

    Google Scholar 

  52. Viehman TS, Hench JL, Griffin SP, Malhotra A, Egan K, Halpin PN. Understanding differential patterns in coral reef recovery: chronic hydrodynamic disturbance as a limiting mechanism for coral colonization. Mar Ecol Prog Ser. 2018;605:135–50.

    Google Scholar 

  53. Weishuhn M. Inciteful: citation network exploration; 2022.

  54. Williams SL, Sur C, Janetski N, Hollarsmith JA, Rapi S, Barron L, Heatwole SJ, Yusuf AM, Yusuf S, Jompa J, Mars F. Large-scale coral reef rehabilitation after blast fishing in Indonesia. Restor Ecol. 2018;27:447–56.

    Google Scholar 

  55. Woodhead AJ, Hicks CC, Norström AV, Williams GJ, Graham NAJ, Fox C. Coral reef ecosystem services in the Anthropocene. Funct Ecol. 2019;33:1023–34.

    Google Scholar 

  56. Zaneveld JR, Burkepile DE, Shantz AA, Pritchard CE, McMinds R, Payet JP, Welsh R, Correa AM, Lemoine NP, Rosales S, Fuchs C, Maynard JA, Thurber RV. Overfishing and nutrient pollution interact with temperature to disrupt coral reefs down to microbial scales. Nat Commun. 2016;7:11833.

    CAS  Google Scholar 

  57. Zhao H, Yuan M, Strokal M, Wu HC, Liu X, Murk A, Kroeze C, Osinga R. Impacts of nitrogen pollution on corals in the context of global climate change and potential strategies to conserve coral reefs. Sci Total Environ. 2021;774:145017.

    CAS  Google Scholar 

Download references


We thank the NOAA National Centers for Coastal Ocean Science and the US Army Corps of Engineers Engineering with Nature for supporting the protocol. We thank Trevor Riley from the NOAA Central Library for reviewing the search string and syntax. We thank T. Barnes, C. Steenrod, and K. Yates for thoughtful reviews of the manuscript. The views and conclusions contained in this document are those of the authors and should not be interpreted as representing the opinions or policies of NOAA and USACE. The mention of trade names or commercial products does not constitute U.S. Government endorsement or recommendation for use.


This study was supported by the NOAA National Centers for Coastal Ocean Science and the USACE Engineering With Nature Program®, and the USGS Coastal and Marine Hazards and Resources Program.

Author information

Authors and Affiliations



TSV and TMS acquired funding for the synthesis. All coauthors conceptualized the project scope. ABP developed search strings with feedback from coauthors. ABP developed the protocol, including the search strategy, article screening and eligibility criteria, data extraction and coding strategy, and the study mapping and presentation vision. ABP and TSV drafted the background section of the protocol. ABP drafted all other sections of the protocol. All authors helped refine the systematic map protocol scope, methods, and manuscript. All authors read, reviewed, and approved the final manuscript.

Corresponding author

Correspondence to Avery B. Paxton.

Ethics declarations

Ethics approval and consent to participate

Not applicable.

Consent for publication

Not applicable.

Competing interests

The authors declare that they have no competing interests.

Additional information

Publisher's Note

Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Supplementary Information

Additional file 1.

ROSES for systematic map protocols checklist.

Additional file 2.

Search strategy development and testing.

Additional file 3.

Benchmarking articles.

Additional file 4.

Data extraction codebook.

Rights and permissions

Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit The Creative Commons Public Domain Dedication waiver ( applies to the data made available in this article, unless otherwise stated in a credit line to the data.

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Paxton, A.B., Swannack, T.M., Piercy, C.D. et al. What evidence exists on the ecological and physical effects of built structures in shallow, tropical coral reefs? A systematic map protocol. Environ Evid 12, 19 (2023).

Download citation

  • Received:

  • Accepted:

  • Published:

  • DOI: