ORCID

Abstract

BackgroundThe presence of artificial structures in our marine environments is increasing rapidly, with negative impacts for biodiversity. Greening of grey infrastructure (GGI) - an eco-engineering method applied to the marine context - aims to increase the ecological value of traditional grey infrastructure, while still allowing it to perform its primary human-centric function. GGI is a rapidly increasing field of research, being tested and implemented worldwide by academics, private practitioners, governments, non-governmental organisations (NGOs), amongst others, using a variety of methods. Outcomes vary widely, and results are communicated across a range of peer-reviewed and grey literature, rendering the evidence base for the effectiveness of GGI fragmented. To inform future decision-making regarding GGI application, it is critical to consolidate and evaluate existing research. To do so, we propose a systematic review and meta-analysis that will answer the following primary question: “What are the effects of GGI interventions applied to marine structures on the diversity, abundance, biomass, composition, and functional diversity of species on or around these ecologically enhanced structures?”. Additionally, we will answer a series of secondary questions relating to intervention type, material use, geographic variations and other relevant associated variables.MethodsThis systematic review will follow the Collaboration for Environmental Evidence Guidelines and Standards for Evidence Synthesis in Environmental Management. Using a defined search string, literature searches will be run in English in at least five databases, three repositories and 10 websites, gathering both peer-reviewed and grey literature. Returns will be screened at title, abstract, and full text levels against defined inclusion criteria. Relevant metadata and effect data will be extracted from each study and used to write a narrative review and, where data allow, a meta-analysis of quantified effects. This review will provide a robust, up to date, consolidated and evaluated evidence base to inform future decision-making regarding the implementation of greening of grey infrastructure methods.

Publication Date

2026-03-05

Publication Title

Environmental Evidence

Volume

15

Issue

1

Acceptance Date

2026-02-09

Deposit Date

2026-04-21

Funding

The authors are grateful to the stakeholders in the advisory group who dedicated their time to input into the research questions, aims and scope of the study, technical language and the identification of sources of grey literature. Thank you to the Natural Environment Research Council (NERC) for funding JA to attend the Collaboration for Environmental Evidence Training Opportunity Course. We extend our thanks to the two anonymous reviewers and the editorial manager. Funding for this protocol and associated systematic review was provided by the University of Plymouth’s School of Biological and Marine Sciences and University College Cork Doctoral Training Partnership, Shezad Dawood Leviathan non-profit, Deutsche Bank, and The Plymouth University Marine Institute.

Keywords

Biodiversity enhancement, Eco-engineering, Environmental evidence, Environmental intervention, Evidence synthesis, Nature-based solutions, Urban ecology

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Additional Files

Additional_File_1-_Supplementary_Information.docx (32 kB)

Additional_File_2-_ROSES_Form.pdf (173 kB)

Additional_File_3-_Search_String_Development.xlsx (60 kB)

Additional_File_4-_Critical_appraisal_schema.xlsx (2075 kB)

Additional_File_5-_Data_Coding_Framework.xlsx (15 kB)

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