Archetypical patterns of barriers and enablers to policy coherence in European marine and coastal governance: a systematic review

1 Introduction

In Europe, marine and coastal areas are increasingly pressured by multiple human activities and the effects of climate change (European Environment Agency, 2019). The policy landscapes in these areas are inherently complex, and the interplay of policies can be visualized along three dimensions: vertical, horizontal, and geographical. This concept is illustrated in Figure 1, expanding on the work of Fanning et al. (2007) regarding large marine ecosystems. It visualizes how governance frameworks are interconnected through policy cycles, stages of decision-making processes, and function across various scales and levels.

The first dimension highlighted in Fanning et al. (2007) framework is the vertical interlinkage of policy cycles across the various governance levels. These considerations are also highly relevant in the context of the multilevel governance landscape that characterizes marine and coastal areas in Europe. The European Green Deal, launched in 2019, calls for a deep transformation in all relevant sectors to create a fair and prosperous society where economic growth is decoupled from resource use, natural ecosystems are protected and restored, and human health improved (European Commission, 2023). Several recent strategies and plans set out an ambitious path for the European seas. Progress toward the Green Deal's objectives takes place within the existing framework of EU law governing these aspects (Platjouw et al., 2024). In addition to the pre-existing body of EU environmental law (including sector-, nature conservation-, and cross-sectoral legislation), new amendments and legislative initiatives have been ongoing to facilitate implementation of various policy targets (Boteler et al., 2024; Kyrönviita et al., 2024). In a domestic policy context, these EU policies may be implemented differently and interplay with national and sub-national policies, as well as international policy frameworks.

A second dimension highlighted by Fanning et al. (2007) refers to the complexity of governance systems, leading to horizontal interplay among policy cycles. Policies and their decision-making processes are typically developed around specific societal or sectoral interests, creating distinct policy areas. However, these areas are horizontally interlinked, and if not properly managed, implementing policies in one area can generate unintended consequences for others. Marine and coastal regions often face the challenge of aligning conservation objectives with sectoral policies that drive sustainable use and resource exploitation under the blue growth paradigm (Platjouw et al., 2024).

A third dimension of marine and coastal policy landscapes reflects the interplay of policies across different geographical scales. The governance of marine and coastal areas is complicated by numerous biophysical and socio-economic interdependencies that span the land-sea interface (Tocco et al., 2024). For instance, land-based activities that lead to runoff and pollution can have a substantial impact on coastal and marine ecosystems (Riemann et al., 2016). Similarly, alterations in marine environments, such as rising sea levels, can affect coastal communities (Ambinakudige, 2020). These complexities are often inadequately addressed in policy frameworks, leading to fragmented efforts in resolving interconnected issues (Tocco et al., 2024). The EU's aquatic environmental policy landscape is characterized by a significant divide between freshwater instruments (Water Framework Directive) and marine instruments (Marine Strategy Framework Directive). This separation creates challenges for achieving an integrated source-to-sea management approach (Sander et al., in press). Challenges arising from limited integration across jurisdictional borders are also particularly pronounced in transboundary contexts, where environmental pressures and policy impacts often extend beyond the jurisdictions of individual states.

Marine and coastal policy landscapes are inherently complex, spanning multiple governance levels, policy areas, and geographical scales. Understanding how policies interplay with one another across these systems, and whether they form a coherent whole, has become increasingly critical. In practice, however, policy objectives and measures are often misaligned or even contradictory, producing suboptimal trade-offs and unsatisfactory outcomes (Platjouw et al., 2025). This phenomenon is referred to as policy incoherence. There remains a pressing need for methodological approaches capable of identifying the structural conditions that generate or alleviate such incoherence.

This paper builds on a systematic literature review to investigate barriers and enablers to policy coherence in European marine and coastal governance. The review was conducted as part of the EU funded BlueGreen Governance project (Fobé et al., 2024). The following section presents the conceptual and analytical framework related to policy coherence. The methodological approach and research design are then presented, followed by the results. Finally, the findings and application of the framework are discussed.

2 Conceptual and analytical framework

2.1 Policy coherence as a pathway for addressing complex governance challenges

Policies are often developed in isolation, targeting specific sectors, governance levels or geographical scales. Limited attention to policy interplay across these three dimensions can lead to disjointed policy frameworks, focusing on isolated fragments of the complex socio-ecological systems they are meant to govern. Due to the multilevel governance system in Europe, European policies often need to be transposed and complied with at (sub)national governance levels. During this implementation process, many factors can influence the achievement of coherent policy outcomes. To illustrate, during policy implementation, achieving the intended outcomes of one policy may be constrained by the simultaneous implementation of other national and EU policies that need to be complied with, especially when incentives across policies are misaligned. Although societal tradeoffs cannot always be avoided, they can be reduced by strengthening policy coherence. Policy coherence refers to how well different policies work together. Platjouw et al. (2025) define policy coherence as

“the extent to which policies strengthen each other by promoting synergies or reducing conflicts between objectives and measures both in design and during implementation”

Low coherence can limit the effectiveness of policies as it increases the probability of making trade-offs that negatively affect achieving multiple policy objectives (Platjouw et al., 2025).

The concept of policy coherence has found resonance both in the policy making community as well as in policy research. A substantial body of literature has emerged, focusing on the assessment of policy coherence (“Are policy landscapes coherent?”). This literature has led to the development of various tools and guidelines for measuring the level of policy coherence. Notably, Nilsson et al. (2012) have made significant contributions by developing a cross-impact matrix approach to assess coherence across policy objectives.

A secondary line of research has emerged around the factors shaping policy coherence (“Why is there policy (in)coherence?”). Tchinda and Talbot (2023) argue that coherence can be influenced by internal layers, such as prevailing discourses and values, as well as external layers linked to stakeholder dynamics and institutional processes. While Tchinda and Talbot's (2023) review has advanced conceptual understandings of policy (in)coherence, there remains a notable absence of operational frameworks that can be applied to specific policy contexts. Meta-analyses of marine and coastal governance highlight persistent challenges across issue-related, institutional, process, and knowledge dimensions, particularly in relation to the complex nature of land-sea interactions (Morf et al., 2022; Tocco et al., 2024). While these meta-analyses provide insightful findings on the challenges of policy coherence, they do not extend to proposing guiding frameworks that would support practical application.

Marine and coastal governance operates within a complex and fluid socio-ecological system, making the achievement of coherence across horizontal, vertical, and geographical dimensions particularly challenging. This paper proposes a guiding framework that identifies patterns of barriers and enablers to policy coherence, providing valuable insights and informing pathways toward more coherent and effective marine and coastal governance.

An additional research novelty of this paper relates to the policy cycle phase where policy coherence is investigated. Tchinda and Talbot (2023) note that coherence is generally desirable during policy design, yet it remains challenging to understand how it can be achieved during implementation. While incoherence may often originate in the design phase, we argue that the implementation phase of policymaking may be even more critical. This is because implementation is where abstract policy objectives are translated into practice, requiring interpretation, prioritization and coordination among various sectoral interests, levels and organizations. Moreover, implementation processes often involve a broader set of stakeholders than in the design phase, whose influence may also affect the coherence of policy outcomes. In multilevel governance contexts, such as European marine and coastal policy, implementation plays a particularly important role. This is because EU-level instruments are transposed and applied at national and sub-national levels, where varying capacities, priorities, and institutional arrangements may either enhance or undermine policy coherence (Sander et al., in press). As such, implementation represents a key arena in which incoherences become visible and are either mitigated or exacerbated. Therefore, this paper considers policy coherence not only as a design issue but also as an implementation issue, aiming to identify the processes that influence and explain why incoherences emerge

2.2 Policy coherence framework

The systematic literature review is structured around the “Policy Coherence Framework” (Platjouw et al., 2025). The “Policy Coherence Framework” was developed under the Horizon Europe CrossGov project through a structured, multi-phase process spanning from September 2022 to early 2025. The framework is composed of two interlinked components. Part A provides a structured assessment of internal and external coherence focusing on the alignment of policy objectives and the measures employed to achieve them. Part B complements this by examining the underlying factors that affect coherent policy outcomes.

In this paper, only the second part of the framework is considered. Part B of the framework encompasses three broad categories of explanatory factors to policy (in)coherence. These were previously identified through a scoping literature review and expert discussions on the concept of policy coherence: (1) “Governmental organizations”, describing the roles and coordination mechanisms across institutions of public policy; (2) “Science-policy-society interfaces” (SPSI), relating to multi-directional and dynamic interactions between knowledge production, policy development, and decision-making; (3) “Stakeholder involvement mechanisms” referring to participatory processes and influence of various perspectives on policy processes. Altogether, these factors shape both policy design and implementation and, depending on context, can act as either barriers or enablers of policy coherence. To further refine the initial framework with these three overarching categories, developed as part of the CrossGov project, this paper sets out to investigate the explanatory factors with more analytical depth, in a more systematic manner, and with empirical evidence from the literature. Therefore, the paper contributes to a refinement of the initially proposed framework.

The paper follows an archetype approach, which is suitable for studying complex socio-ecological systems and has been applied in similar reviews (Oberlack, 2017). Archetype analysis explores recurring patterns at a moderate level of abstraction to support the development of explanatory models tailored to specific conditions. This approach makes it possible to identify common patterns while still preserving important contextual particularities (Eisenack, 2012; Oberlack et al., 2019). To delineate these contextual particularities, the study is situated within the domain of European coastal and marine policy. The main difference between archetype patterns and grand theories is that archetype patterns are not considered universally valid but are sufficiently evidenced to be applicable to other cases (Eisenack, 2012).

The research question guiding this paper is: Which recurring archetypical patterns of barriers and enablers influence policy coherence in European marine and coastal governance? The review advances understanding of marine and coastal policy coherence across three dimensions (vertical, horizontal, and geographical) and concludes with policy recommendations building upon the archetypical patterns.

3 Material, methods and research design

3.1 A systematic literature review approach

A systematic literature review (SLR) is an appropriate methodological approach for qualitative data analysis, facilitating the application of theoretical concepts in the literature while ensuring analytical transparency and transferability (Bingham, 2023). SLRs synthesize dispersed knowledge from individual studies, providing evidence for why and how phenomena occur. The PRISMA 2020 guidelines were applied to structure the study identification and screening process (Page et al., 2021). There is significant precedent for using a SLR approach in policy research on institutional barriers, enablers, and policy coherence (Oberlack, 2017; Righettini and Lizzi, 2021; Tchinda and Talbot, 2023).

3.2 Search design and identification of studies

The analytical investigation of barriers and enablers to policy coherence has been situated within a broader SLR process performed as part of the BlueGreen Governance project, requiring a multi-phased research design. The initial literature search was performed across different researcher sub-groups, necessitating a search string that captures a more comprehensive body of relevant literature on institutional complexities in European marine and coastal governance (Table 1). The search string was applied to the Web of Science (WoS) and Scopus databases. The inclusion criteria for the retrieved studies were peer-reviewed articles, early access, and book chapters written in English and published between January 2014 and February 2024. The timeframe was selected based on major revisions of European marine and coastal governance in 2014 following the implementation of the Maritime Spatial Planning Directive, justifying the choice of the lower-bound year. Review articles were excluded to avoid duplication of data. This SLR used the European Environmental Agency's definition of European countries and included only those with coastal access in the search string.

Table 1. Search string for the identification of relevant studies.

3.3 Screening process

The identified studies from the databases were imported into the Hubmeta platform, a supportive tool for the SLR screening process (Steel et al., 2023). Following the removal of duplicates, 1,444 studies were selected for the first screening. Because of the project's research design, the researchers first carried out a shared initial literature identification and screening round, before branching into thematic sub-themes. As a result, the screening process was conducted in two rounds, with sub-theme specific screening criteria added to the second screening round. An overview of the inclusion criteria during the two-staged screening phase can be found in Table 2.

Table 2. Screening criteria for the selection process.

The first screening round (only abstracts) served to identify a broader body of relevant literature on marine and coastal governance across the project. This resulted in a selection of 421 studies. The second round of screening included abstract and full text screening and was performed by the researchers investigating the sub-theme of policy coherence, applying the more thematic screening criteria. This reduced the number to 72 studies. During the entire screening process, each study was reviewed by two researchers independently, and disagreements were resolved through negotiations. Figure 2 illustrates the screening process flowchart, detailing the steps to narrow down the initial 1,444 identified studies to 72 retrieved studies based on the search criteria.

3.4 Codebook and data extraction

Deductive and inductive qualitative coding approaches were used in this project. Deductive codes are based on existing theories or assumptions and are defined a priori to the coding process, while inductive codes are developed by researchers during data analysis. Inductive codes capture emerging patterns and can add an additional layer of coding to refine the deductive codes (Bingham, 2023). Following Saldana (2021) two-stage coding cycle approach, this paper's research design combined an initial round of deductive coding with a subsequent round of inductive coding.

With the aim of this study being to test, validate and refine the “Policy Coherence Framework” (Platjouw et al., 2025), the deductive codebook used for the first coding cycle is structured around its three explanatory factors. The broader research questions associated with the three explanatory factors under the initial framework were converted into deductive coding categories of barriers or enablers, as illustrated in Table 3.

Table 3. Codebook (deductive codes).

These deductive codes build on the prototype framework developed as part of the CrossGov research project.

The 72 selected papers were extracted from the Hubmeta platform before being processed by an AI-supported coding algorithm to support data extraction. There is sufficient evidence in applying AI in the abstract and title screening phase of SLRs (Bolaños et al., 2024; van Dijk et al., 2023; Wagner et al., 2022), whereas fewer studies have focused on the role of AI in data extraction (Bolaños et al., 2024). The coding algorithm, developed as part of this project, leveraged GPT-4 (OpenAI) to apply the predefined coding scheme and generate responses in an Excel file. The coding scheme followed the deductive codes outlined in Table 3, and definitions of each explanatory factor, based on Platjouw et al. (2024), were incorporated into the algorithm's prompts. For each study, the algorithm identified up to three key barriers and enablers each, selecting those most relevant to the study's arguments, and provided a brief explanation of the supporting evidence for each code selection. If a relevant barrier or enabler could not be assigned to an existing deductive code, it was highlighted under the category “other.” A group of researchers then read through the paper to review and manually adjust the codes and explanations to ensure quality. This was necessary because AI was found to have limited capacity to conduct the necessary interpretive analysis required for a systematic literature review. The AI-generated codes often lacked sufficient quality, especially when dealing with studies that included multiple case studies or extensive background sections. Despite shortcomings in the analytic capacity to effectively assign appropriate codes, the use of AI coding was considered useful and timesaving.

The results of the first coding round were organized into tables for each of the deductive codes. In a second coding round, researchers analyzed the results and assigned new inductive codes to reflect commonalities and recurrent patterns (archetypes) within each deductive category. One researcher initially assigned the inductive codes individually, which were then reviewed and modified after discussions with a second researcher. Since the search string and resulting body of literature was more oriented toward governance challenges than solutions, the inductive codes were developed based on the analysis of the identified barriers. For the enablers, the inductive codes were reversed (e.g., “Absence or limited capacity of a clearly leading authority” was framed as “Presence of a clear leading authority”), and results retrieved from the deductive coding were assigned to these inductive codes. Additional inductive codes were created for those retrieved examples of enablers that did not fit into any of the inductive codes previously created.

3.5 Study limitations

To minimize the risk of partial overlaps between coding categories, the researchers initially coded a selection of studies together and held regular meetings to align their understanding of the coding categories and discuss examples. Although this SLR includes some quantitative results, the research design primarily focused on qualitative aspects. Therefore, the subjective classification of examples does not compromise the robustness of the results.

Another point of consideration pertains to the strength of evidence, specifically of identified enablers. While barriers were in almost all cases linked to empirical observations based on case studies or similar, some of the enablers were grounded on expert and/or author recommendations. Since the sample of studies only includes peer-reviewed studies, the authors concluded that both types of evidence should be considered as valid for the archetype approach. Differentiation of these types of evidence in future research could provide additional insights into the conduct of an SLR.

4 Results

The principal outcome of this SLR is a refined categorization of the “Policy Coherence Framework”, introducing an additional analytical layer that identifies archetypical patterns of barriers and enablers to policy coherence. These archetypes are organized according to the three explanatory factors of the prototype framework developed in the early stages of the CrossGov project: (1) governmental organizations, (2) science-policy-society interfaces, and (3) stakeholder involvement mechanisms. Within each explanatory factor, the subheadings correspond to specific attributes, which are operationalized as the deductive codes applied during the initial coding phase. The inductive codes, representing the archetypical patterns identified through the SLR, are highlighted in bold throughout the following section, which elaborates on these archetypes, supported by empirical examples from European marine and coastal governance.

Figure 3 provides an overview of how frequently different attributes are mentioned in relation to barriers and enablers. The results show that barriers and enablers associated with governmental structures are the most cited explanatory factors. Among the individual attributes, coordination mechanisms receive particularly high attention, being frequently discussed in relation to both barriers and enablers. In addition, barriers related to data availability and knowledge are also commonly reported.

Table 4 provides a comprehensive overview of this archetypical structure. References to the inductive codes are provided in the annotations of Table 4.

Table 4. Archetypical patterns of barriers and enablers to policy coherence.

The deductive codes are color-coded, the inductive codes (archetypes) are uncolored. The number (#) indicates the frequency a specific barrier or enabler was reported. The identification numbers refer to the following references that supported the identification of archetypes: 1 (Westholm, 2022); 2 (Wamsler et al., 2014); 3 (Amani Fard et al., 2023); 4 (Ansong et al., 2022); 5 (Antonson et al., 2016); 6 (Apolonia et al., 2021); 7 (Ballinger, 2015); 8 (Black et al., 2019); 9 (Blenckner et al., 2015); 10 (Bocci et al., 2024); 11 (Brennan et al., 2014); 12 (Brown et al., 2017); 13 (Bruckmeier, 2014); 14 (Buono et al., 2015); 15 (Cantasano et al., 2017); 16 (Cavallo et al., 2017); 17 (Cinnirella et al., 2014); 18 (de Koning et al., 2021); 19 (Den Uyl and Russel, 2018); 20 (Elliott et al., 2023); 21 (Elliott et al., 2018); 22 (Kelly et al., 2018); 23 (Ferreira et al., 2014); 24 (Fidélis and Carvalho, 2015); 25 (Fraschetti et al., 2018); 26 (Walsh, 2019); 27 (Tynkkynen et al., 2014); 28 (Frazão Santos et al., 2015); 29 (Galdies et al., 2020); 30 (Gee et al., 2024); 31 (van Tatenhove, 2017); 32 (Gómez-Ballesteros et al., 2021); 33 (Göransson et al., 2021); 34 (Hammer, 2016); 35 (Hassler et al., 2018); 36 (Jouanneau and Raakjær, 2014); 37 (Karlsson, 2019); 38 (Karrasch et al., 2023); 39 (Kelly et al., 2019); 40 (Therville et al., 2019); 41 (Kull et al., 2021); 42 (La Jeunesse et al., 2015); 43 (Lange et al., 2018); 44 (Lillebø et al., 2020); 45 (Moodie and Sielker, 2022); 46 (Morf et al., 2017); 47 (Muccitelli et al., 2023); 48 (van Hoof and Kraus, 2017); 49 (O'Hagan et al., 2020); 50 (Oliveira et al., 2020); 51 (Österblom et al., 2017); 52 (Pecceu et al., 2016); 53 (Pendleton and Carr, 2023); 54 (van der Molen et al., 2015); 55 (Piwowarczyk and Wróbel, 2016); 56 (Pinarbasi et al., 2020); 57 (Pröbstl et al., 2023); 58 (Raakjaer et al., 2014); 59 (Ramieri et al., 2024); 60 (Ramírez-Monsalve et al., 2016a); 61 (Ramírez-Monsalve et al., 2016b); 62 (Vaidianu et al., 2020); 63 (Ribeiro, 2017); 64 (Sandersen and Kvalvik, 2014); 65 (Satta et al., 2016); 66 (Sayers et al., 2021); 67 (Schmidt et al., 2022); 68 (Solomun et al., 2022); 69 (Soma et al., 2015); 70 (Spijkerboer, 2021); 71 (Steins et al., 2021); 72 (Stori et al., 2023).

4.1 Governmental organizations

Governmental organizations, at multiple governance levels, establish the framework for policy formulation and implementation. They define the roles, responsibilities, and coordination of relevant organizations, impacting policy coherence (Platjouw et al., 2025). The SLR highlighted that mandates, responsibilities, and coordination mechanisms within and across governmental organizations were amongst the most frequently reported explanations for policy (in)coherence.

4.1.1 Mandates and roles

This attribute relates to how the clarity and allocation of mandates and roles across governmental organizations shape policy (in)coherence. Unclear mandates and roles were identified among the most frequent barriers to coherent marine and coastal governance. A commonly observed issue, particularly pronounced in coastal areas, is the existence of various organizations with overlapping or competing mandates. The absence of a clear leading authority results in fragmented and uncoordinated efforts that hinder coherent management approaches. In other cases, the unclear management responsibility or legal mandate to act on a specific policy issue, such as climate change adaptation in coastal areas, can lead to fragmented efforts and inaction. To overcome these barriers, specifically appointed roles or committees can ensure better accountability, coordination and leadership. For instance, to align dispersed flood risk management planning in England involves assigning strategic oversight to the Environment Agency. When designating a lead responsibility to a central organization, the authors highlight that it is crucial to ensure collaboration and integration with local authorities and their expertise (Sayers et al., 2021).

At the transboundary level, the unclear responsibilities or the absence of a single supranational body often arise from overlapping jurisdictions and are a recurrent barrier to ensure coherent approaches in environmental cooperation and marine spatial planning (MSP). These challenges are partially caused by the ambiguity in legal frameworks which are transposed heterogeneously at the level of member states. EU Directives, such as the MSP Directive, are adopted in light of the domestic governance contexts, resulting in different approaches. Moreover, the unclear articulation between different legal frameworks at the EU level [e.g., the Marine Strategy Framework Directive (MSFD), the MSP Directive, and the Integrated Coastal Zone Management (ICZM) Recommendations] is passed down to national and sub-national levels. This results in heterogeneous approaches to implementation within national and sub-national governmental organizations.

Fragmented governmental organizations with conflicting or overlapping responsibilities are therefore a commonly observed barrier to coherent approaches. Coastal management, which requires integrated strategies across the land-sea interface, often suffers from divided and siloed management responsibilities. The literature indicates that these responsibilities are frequently split among several governmental organizations, separating land from sea. This can result in inefficiencies and uninformed policy interventions. Adapting to climate change is becoming an increasingly pressing issue, particularly in coastal areas. In this regard, disjointed governmental organizations with unclear and isolated responsibilities can even lead to maladaptation, as demonstrated by a case of interventions on coastal defense structures that did not consider managed realignment strategies prepared by a separate organization (Brown et al., 2017).

Integrating governmental organizations across sectoral levels and geographical scales can be one way to circumvent this land-sea fragmentation of management responsibilities. In the case of Sweden, the establishment of a marine and freshwater agency was intended to overcome the silos between marine and fisheries management. The authors however argued that this re-organization achieved limited success due to a lack of leadership and consideration of cultural factors, and freshwater issues were not sufficiently integrated (Pendleton and Carr, 2023). This indicates that structural reorganization of governmental organizations due to political or administrative changes should be accompanied by clearly defined responsibilities.

Ambiguity regarding financial responsibility and unresolved questions about which organization should fund infrastructure assets or realignment interventions present another barrier to effective and well-integrated policy interventions.

4.1.2 Coordination mechanisms

This attribute focuses on how various types of coordination mechanisms across boundaries of governance organizations affect coherence. The absence of adequate coordination mechanisms is reported as a clearly manifested barrier to coherent policymaking, at all levels of governance.

Marine and coastal ecosystems transcend administrative borders; however, several studies suggest that cross-border MSP and MSFD implementation are hampered by the absence of adequate coordination bodies at the transboundary level. The cooperation established through the Regional Seas Conventions is recognized as important venues for transboundary cooperation and toward a more coherent implementation of EU Directives. Not only do they facilitate dialogue on marine resource management at a regional scale; but they also provide a venue for cooperation on transboundary MSP. The formalized cooperation between the Regional Sea Convention HELCOM with VASAB (Vision and Strategies around the Baltic Sea), is highlighted in this regard (Hassler et al., 2018; Karrasch et al., 2023). Further integration between the Regional Seas Conventions and the EU, as well as non-EU states, is recommended in the literature. In the Baltic Sea, the EU has enhanced its interactions with HELCOM by adopting a dedicated Strategy for the Baltic Sea Region, promoting synergies between the implementation of EU legislation and transnational regional cooperation under HELCOM (Tynkkynen et al., 2014).

Another frequently observed barrier is the limited coordination and challenges associated with multilevel governance landscapes, causing fragmented and disconnected policy efforts. This can lead to poorly informed policy decisions, as seen in instances where a lack of coordination and conflicts between local and regional governance levels resulted in limited integration and alignment of climate change considerations into spatial planning. While devolving governance responsibilities can potentially enhance the integration of local perspectives, it may also lead to an increase in the number of responsible organizations, thereby complicating coordination across different levels of governance. To ensure effective multi-level coordination, it is recommended that lower governance levels are consulted and integrated into regional and national strategies for coastal and marine management, including regular interactions to achieve a shared long-term vision.

In addition to vertical coordination challenges, limited horizontal coordination across boundaries of governmental organizations is another prominent barrier. Whereas limited coordination across siloed sectoral organizations is indicated as one of the main barriers to policy coherence, the literature also indicates limited coordination across geographical scales as well as challenges due to the existence of many organizations, particularly in coastal areas. Coordination efforts can also be complicated implementation of multi-use scenarios in Dutch MSP, due to the when responsibilities for legal frameworks are fragmented across separate governmental organizations. One example related to the difficult fragmented regulatory landscape involving several organizations (Steins et al., 2021).

The literature suggests several pathways to how effective coordination across organizational boundaries can be established. Multi-sectoral or multi-agency committees or steering groups are an often-employed technique to enhance coordination. Establishing an overarching strategy or management plan is another approach that can support coordination by creating shared understanding, vision, and commitment toward shared objectives. Similarly, involving multiple governmental organizations in joint projects can foster interactive dialogue and enhance collaboration. It is however emphasized that existing challenges in coordination across fragmented legal and organizational frameworks are not easily resolved by adding additional layers of coordination, due to path dependencies and unresolved fragmentation issues.

Incoherent planning approaches can also be a result of authorization and licensing processes being spread across various governmental organizations, without an adequate coordination body for this specific policy issue. Streamlining these processes by designation a coordination authority can facilitate these processes.

Furthermore, the lack of a coordination mechanism for resolving conflicts between various interests and organizations can result in impasses and unresolved trade-offs, undermining policy coherence.

4.1.3 Geographical and temporal scales

This attribute expresses how mismatches or alignments between temporal and geographical scales influences coherence. Limited consideration of relevant geographical and temporal scales is a recurrent pattern that helps to explain why policy interventions often fail to address interconnected policy issues in a coherent approach. Implementation of EU Directives (such as the MSFD) across large geographical scales require coordination across organizations and jurisdictions, challenging coordinated efforts.

Another common mismatch can be observed between ecological and administrative boundaries. For example, the MSFD and the WFD (Water Framework Directive) apply to different geographical scales and timelines and lack a unified coordination structure, which poses a barrier to coherent water management from source to sea. These observations of the land-sea divide also pertain to spatial planning, highlighting the limited connection between marine and coastal planning. Therefore, it is recommended to enhance their coordination.

Incoherences in management strategies can arise from differing priorities and competencies at various governance levels and geographical scales. National governments, which have planning authority at sea, tend to operate on longer time scales and have different priorities compared to local authorities, who often focus on immediate socio-economic concerns along the coast. This disparity can lead to divergent visions and fragmented, sometimes conflicting, strategies.

Temporal misalignments between policy issues and political priorities can lead to ineffective policy interventions, particularly in climate adaptation. While long-term measures are necessary to address these issues, short-term political funding and electoral cycles often undermine these efforts. For example, in Sweden, electoral pressures caused local planning authorities to support short-term engineering solutions that maintain current lifestyles along the coast, whereas regional planning authorities adhere to national guidelines on managed retreat to decrease exposure from future sea level rise (Antonson et al., 2016).

4.1.4 Resource allocation

This attribute reflects how the availability and distribution of resources affect policy coherence. Insufficient resource allocation also hampers integrated management approaches. The shortage of dedicated funds and resources restricts staff efforts, cooperation, and enforcement, leading to weaknesses in integrated management frameworks. Supranational funding mechanisms, such as those from the UN or EU, can help support integrated management. Government austerity measures are another frequently observed obstacle, with recurring budget cuts affecting environmental and coastal climate adaptation efforts.

4.1.5 Political processes and power dynamics

This attribute examines how political support, institutional dynamics and power asymmetries shape policy coherence. A lack of political support or endorsement for policy frameworks or management tools can compromise their long-term effectiveness and lead to implementation challenges. Incoherences can also arise from uneven power dynamics, where dominant sectoral interests shape the policy-making process to serve their own objectives and agenda. These imbalances restrict the integration and consideration of diverse interests and perspectives. For example, Spijkerboer (2021) argue that the strong influence of the offshore wind sector in Dutch marine spatial planning has hindered truly integrated planning, leading instead to “strategic sectoral planning.” These power imbalances can also occur when there is participation of various governance levels holding different powers and interests, hence complicating efforts toward coherent management approaches.

On a transboundary level, cooperation that would be required for coherent implementation of the MSFD or Marine Protected Area (MPA) management can be undermined by political obstacles, such as limited willingness to coordinate regionally, as well as weak transnational structures and conflicts between states.

4.2 Science-policy-society interfaces

Science-policy-society interfaces (SPSI) are multi-directional social processes that influence dynamic interactions between knowledge production, policy development, and decision-making. These interfaces can be examined within specific SPS systems, focusing on the involved actors and their roles throughout the policy cycle. Effective SPSI can promote and support policy coherence, which relies on science and knowledge to provide a shared evidence base to support transparency in decision-making. This evidence base should incorporate and consider science and knowledge from various policy areas (Barbanti et al., 2023; Platjouw et al., 2024).

4.2.1 Fragmented data and knowledge

This attribute relates to how the availability, accessibility and integration of data and knowledge influence coherent policymaking. Evidence-based decision-making in marine and coastal governance is challenged when data and knowledge is unavailable or widely dispersed across organizations, systems, and formats. The barrier of fragmented data and knowledge manifests in various ways at SPSI with implications for policy coherence. The absence or paucity of relevant data about the marine environment is highlighted as a major deficit. This can limit environmental considerations in decision-making processes and cause conflicts among stakeholders, undermining integrated management approaches (Pecceu et al., 2016). Several papers suggest data shared and made accessible through research projects or open-access data portals, can increase knowledge availability and support the integration of science into decision making (Gee et al., 2024; Gómez-Ballesteros et al., 2021). Another recurrent barrier is data being fragmented across knowledge providers and knowledge systems. These divisions occur along the boundaries of disciplines (natural-physical and socio-economic), sectors and geographical scales. The limited consideration of various knowledge systems and lack of shared understanding among different stakeholders can cause conflict or inaction. To alleviate these challenges, it is recommended to integrate various sources of knowledge into the management process. Fragmented data are sometimes a result of different legal frameworks (e.g., EU Directives) that set out their own system for data collection. Not only does this pose a barrier to integrated management approaches, but it also puts high pressure on scientific advisory systems. Generally, the lack of harmonized/standardized cross-border data sources poses challenges for coherent transboundary marine spatial planning. The creation of transboundary maps and integrated geo-spatial tools across borders is an efficient way to improve transboundary marine spatial planning processes. Temporal mismatches of data availability and policy needs, for example, when data sources are outdated or updated at different time intervals than required by policies and decision-making can also challenge SPSI.

4.2.2 Inadequate assessments and monitoring systems

This attribute reflects how the design and coordination of assessment and monitoring systems affect policy coherence. Inadequate assessments and monitoring systems are often manifested by an absence of shared assessments at the transboundary level. Environmental assessments being conducted at the level of individual member states instead of regional coordination can cause varying approaches and temporal delays, which act as a barrier to effective transboundary planning. Planning based on shared environmental assessments at a transboundary level can support improved coherence through effective implementation of EU Directives (MSFD and MSP). Separate monitoring systems, sometimes stemming from different legal systems, limit effective understanding of a policy issue that is caused by interactions across large jurisdictional scales. Uninformed policy choices can also arise due to inadequate impact assessments that fail to capture cumulative impacts and a lack of tools to understand the effect of a policy. To overcome weaknesses in the impact assessments, the literature suggests several tools for improved planning processes. These include for instance the use of the ‘Best Expert Judgement' method to address gaps in data needs (Elliott et al., 2018) or the use of international guidelines that outline a standardized approach for application at national level. Scenario planning can support shared problem understanding and facilitate the integration of knowledge into decision-making.

4.2.3 Knowledge platforms

This attribute sheds light on the role of formal and informal knowledge platforms in facilitating knowledge exchange and supporting coherent decision-making processes. An important aspect relates to the dynamic processes of how knowledge is transferred between knowledge providers and policymakers. Knowledge platforms that collect, manage, and make information related to marine research accessible and understandable can support the design and implementation of coherent policies. The absence of permanently integrated knowledge platforms as well as limited coordination across government organizations and knowledge providers was found to produce uncoordinated efforts and be a barrier to integrated management interventions. The existence or establishment of knowledge transfer platforms (e.g., established partnerships, networks, fora or information centers) contribute to better informed and coordinated efforts by supporting the compilation and sharing of data (Schmidt et al., 2022; Tynkkynen et al., 2014). They can also be an important platform for disseminating knowledge to the wider public, increasing awareness and engagement for a policy intervention. The importance of dialogue between knowledge providers, decision makers and other stakeholders, for example through workshops and courses or through advisory councils and co-creation of policy interventions, has also been highlighted as an important contribution.

4.3 Stakeholder involvement mechanisms

Stakeholder involvement mechanisms refer to how participatory processes (e.g. consultations, dialogue meetings, and workshops) enable stakeholders to influence policy framing, design, and implementation. Stakeholder engagement processes occur on a spectrum with varying levels of information exchange, knowledge, values and ideas for direct influence or more tokenistic forms of involvement. Inclusive, participatory mechanisms with adequate involvement of relevant actors and interests are more likely to have a stronger contribution to coherence than processes involving few interests that may be typical “clients” for one sector only (Platjouw et al., 2024). While stakeholder involvement is often associated with positive outcomes for policy coherence, there are also challenges related to greater process complexity, inaction and thereby contributing to policy incoherence.

The lack of transboundary platforms or mechanisms, as well as the lack of involvement of local stakeholders in transboundary processes are identified as barriers to effective stakeholder involvement processes. They can both lead to a lack of trust in the planning system as well as hinder integration of knowledge and perspectives (Ansong et al., 2022; Pinarbasi et al., 2020). The literature recommends the establishment of transboundary platforms or forums for collaboration, such as initiatives at the regional seas level that can facilitate the sharing of knowledge and collaboration among scientists, governments, and stakeholders (Hassler et al., 2018).

The lack of coordinated approaches for stakeholder involvement across policy areas is another barrier to policy coherence, identified in the literature. Stakeholder involvement across policy areas is especially important at the land-sea interface, however, several papers highlight an absence of coordinated multi-sector stakeholder involvement processes in specific geographical scales or limited coordination of stakeholders' involvement processes across policies. Coordinated approaches for stakeholder involvement contribute to better horizontal policy coherence.

The lack of (or weak) formalized mechanisms for involving stakeholders is recognized as a barrier to integrated management measures, potentially leading to conflicts. The literature provides many good examples of enablers to strengthen such formalized mechanisms, such as the establishment of formalized partnerships, coalitions or formal processes for stakeholder involvement. Some examples of this being the Severn Estuary Partnership (Ballinger, 2015), the Baltic Environmental Forum (Raakjaer et al., 2014), and the Dutch North Sea Dialogues and Agreement (Spijkerboer, 2021). Stakeholder engagement can also be formalized through guidelines and protocols. Setting up stakeholder involvement as an integral element of ICZM or MSP (or EBM) management practices is also considered essential.

Uneven stakeholder engagement has been identified as the largest barrier to stakeholder involvement. The lack of representation of certain stakeholders in the development of a plan, policy or decision, involving (some) stakeholders late in processes, or uneven power dynamics affecting the implementation of the plan, policy or decision are key barriers (Kelly et al., 2018; Pröbstl et al., 2023). In general, the importance of a representative and balanced involvement of stakeholders in the development of a plan, policy or decisions is highlighted. This includes the involvement of local stakeholders, as well as a diverse set of stakeholders representing the public, organizations, state, municipalities, etc.

Emphasis is not only put on adequate and representative involvement, but also on effective stakeholder involvement, including processes that are clear and transparent with respect to the process, roles of certain bodies, and varying perspectives. Ineffective stakeholder involvement can be caused, for example, through a lack of power and influence on final outcomes or opaque stakeholder involvement processes causing uncertainty about the process, roles, and interests at stake. It is recommended that stakeholder perspectives have an influence on the final outcome of the process, and that stakeholders are informed about the potential outcomes of the processes in advance to avoid misunderstandings.

5 Discussion

By systematically analyzing the evidence from the European marine and coastal governance literature across three explanatory factors, recurring archetypical patterns of barriers and enablers are identified that influence policy coherence. The results are discussed in light of the initially proposed concept of policy interplay in complex multi-level systems that characterize marine and coastal areas, with attention to policy recommendations and their relevance beyond the scope of this study.

5.1 Archetypes revisited along vertical, horizontal and geographical dimensions

Eisenack (2012) suggest that recurring patterns (archetypes) identified across diverse empirical cases serve as building blocks that can facilitate the sharing of experiences and learning both within and beyond the studied cases. These archetypes can be transformed into broad policy recommendations to guide planning and decision-making processes.

The paper's introduction highlights how European marine and coastal governance reveals policy interplay across three dimensions: vertical, horizontal, and geographical. Revisiting these dimensions by linking them to the archetypes structured around the explanatory factors of the “Policy Coherence Framework” provides an opportunity to generate more nuanced policy recommendations. However, the core principle of the archetype approach is reaffirmed: the recommendations are not universal truth but must always be interpreted in light of context. Variations in legal systems, administrative structures, and policy cultures may require adaptations to ensure their continued relevance.

Firstly, the mandates, roles and coordination mechanisms across governmental organizations are an important reason for policy (in)coherences, and power imbalances between actors may further exacerbate incoherences. Vertically, actors and authorities at different governance levels often operate with varying planning priorities and time horizons, which can result in disconnected or even contradictory policy incentives. These challenges may be reinforced by asymmetric power relations, where higher governance levels shape priorities with limited input from local or regional actors. It is therefore important to clearly define roles and ensure meaningful coordination and engagement across governance levels during the development and implementation of national policies. On the horizontal dimension, sectoral silos represent a key source of incoherence in decision-making, and these may be particularly pronounced when dominant sectors exert disproportionate influence over policy processes. To address these challenges, cross-sectoral strategies or integrated management plans are recommended, as they can foster shared visions, enhance transparency, and support more balanced participation in decision-making. From a geographical perspective, the misalignment between administrative boundaries and ecological realities often leads to overlapping responsibilities or gaps. This challenge is particularly evident at the land-sea interface, where policy instruments are frequently designed and applied on only one side of the administrative divide. Enhancing geographical coherence requires deliberate recognition of cross-boundary interactions within legal frameworks, coupled with stronger practical coordination among authorities operating along the land-sea interface. These findings align with the meta-analysis by Tocco et al. (2024), which underscores that land-sea interactions remain insufficiently embedded in governance and highlight the need for stronger coordination and collaborative approaches.

Secondly, the evidence on Science-Policy-Society Interfaces (SPSI) highlights the critical role of knowledge systems in shaping coherent policymaking. The horizontal fragmentation of knowledge and data is apparent across sectoral silos and disciplines, requiring improved data sharing practices. This should also involve industry actors and various other knowledge source holders. Moreover, the complex interactions of policy issues at the land-sea interface are poorly captured due to fragmented knowledge practices across these geographical divides. This challenge is further amplified by legal frameworks that establish data collection and monitoring systems covering only parts of the interface. Addressing these gaps requires that knowledge-production processes mandated by law ensure stronger alignment across geographical domains, for instance by harmonizing indicators and integrating monitoring platforms or reporting requirements. Furthermore, marine and coastal policy issues often also extend beyond national borders, yet the research highlights a significant gap in transboundary cooperation at the supranational level. This gap undermines the efficiency of vertical knowledge transfer from supranational to national governance, and it thus recommended to enhance the role of shared environmental assessments and harmonize data across national borders within shared portals. The Regional Seas Conventions play an important facilitator in this regard.

Finally, the research documents that stakeholder involvement mechanisms are both a prerequisite and a challenge for increased policy coherence. Barriers pertain to the exclusion of local actors in national processes, lack of transboundary engagement mechanisms, and uneven representation across sectors and geographical scales. This relates specifically to the limited inclusion and power imbalances of coastal stakeholders within marine spatial planning processes. Enablers stress the need for transparent, inclusive approaches that elevate local perspectives and ensure balanced representation. Horizontal coherence is supported by coordinated multi-sector involvement, often through advisory bodies or communities of practice. Geographically, applying guidelines that ensure stakeholder representation across the land-sea interface can foster legitimacy and responsiveness in planning.

5.2 Methodological considerations on universal applicability

A crucial aspect of institutional research involves determining whether the findings possess generic validity beyond the specific empirical sample examined in the study. Oberlack (2017) argues against the existence of unequivocal governance principles due to two main factors: detailed complexity and trade-offs. Detailed complexity implies that contextual factors influence the way an institutional attribute affects governance outcomes. Trade-offs further complicate generalization, as a single attribute can shape different dimensions of governance in opposing ways (Oberlack, 2017). To illustrate, Oberlack (2017) argues that strong leadership is often regarded as an institutional enabler; however, when combined with pronounced power asymmetries, it may produce adverse effects on both the fairness and efficiency of outcomes. Stakeholder inclusion may enhance legitimacy while simultaneously increasing transaction costs and slowing decision-making, potentially leading to impasses (Oberlack, 2017). Evidence from this review substantiates both dynamics. While coordination mechanisms are frequently recommended as mechanisms to enhance policy coherence, their effectiveness is highly context dependent. When such mechanisms operate within settings characterized by strong power asymmetries, they may reinforce the dominance of specific sectoral interests rather than facilitate balanced integration. The Dutch North Sea Agreement illustrates this tension well: although it was established to address coordination challenges among governmental organizations and stakeholders (de Koning et al., 2021), the process has been shown to be strongly influenced by the offshore wind sector, thereby shaping MSP outcomes in ways that privilege sector-specific objectives over broader integrative goals, hampering balanced considerations of stakeholder interests (Spijkerboer, 2021). Likewise, in Ireland, the establishment of coordination structures such as the Marine Coordination Group did not fully resolve fragmentation, as its limited authority and sectoral silos continued to hinder integrated decision-making (Lange et al., 2018). These examples underline that institutional attributes cannot be assessed in isolation from their governance context.

To address these challenges, this study adopts an archetype approach (Eisenack, 2012), which seeks to balance generalization with sensitivity to context. Eisenack notes that

“the particular feature of archetype analysis is to understand the dynamics of social-ecological systems in a way as general as possible, but fine-grained enough to account for local particularities.” (Eisenack, 2012, p. 5)

Consequently, this method considers identified patterns as general building blocks rather than universally applicable principles. By focusing on European marine and coastal governance, the analysis maintains a degree of contextual specificity while still enabling transferable insights. Importantly, the identified barriers and enablers should not be interpreted as fixed or binary categories. Instead, they exist along a continuum, where their role may shift depending on how they interact with other institutional attributes and contextual conditions.

Building on this, future research could further explore how different institutional attributes interact with one another, including potential synergies and trade-offs across explanatory factors. This could be advanced by analyzing the co-occurrence of attributes through meta-analytic approaches, identifying clusters of related barriers and uncovering underlying patterns, as suggested by Nielsen et al. (2023). Such analyses may also clarify cross-cutting mechanisms that link barriers and enablers across different explanatory factors. In addition, longitudinal qualitative studies of a given governance arrangement could further trace how these relationships evolve over time, revealing how attributes interact dynamically across policy phases and respond to shifting institutional and political contexts.

5.3 Potential areas of application

The archetypal structure developed through this SLR can be applied in both policymaking and research contexts. Importantly, the framework should be understood as a flexible analytical structure that can be adapted to the specific contextual setting of the analysis. For instance, analyses may focus on a single explanatory factor or selectively consider those attributes most relevant to the identified research or policy question. In academic contexts, the archetype framework is proposed as a tool to guide empirical research, and its applicability has been demonstrated by Sander et al. (in press). In their study, the authors investigated how policy coherence between freshwater and marine policies is operationalized across Europe. While policy incoherences are identified within the EU framework and shown to cascade into national contexts, the authors argue that member states retain considerable discretion during the transposition and implementation of EU directives, allowing them to mitigate some of the coherence challenges originating at the EU level. By applying the three explanatory factors as an analytical lens, the study compares how countries adopt distinct approaches to enhancing coherence at the national level. For example, one country prioritizes a science-based approach by aligning modeling and monitoring systems across freshwater and marine domains, whereas another emphasizes strengthening coordination mechanisms between the respective governmental organizations (Sander et al, in press). In this way, the explanatory factors provide a useful lens for understanding and comparing how coherence challenges arise and how they may be addressed across different governance contexts. The study further demonstrates the value of the archetype framework for analyzing the implementation phase of policymaking, as it captures the diverse institutional, knowledge-related, and participatory dynamics that shape the coherence of policy outcomes in practice. Within the policymaking community, the proposed archetypes can serve as guiding elements, functioning as a structured checklist to support the design and implementation of more coherent marine and coastal policies. In light of ongoing efforts to consolidate and align European marine governance, particularly through the Ocean Pact and the forthcoming Oceans Act, the importance of strengthening policy coherence has been repeatedly emphasized by the EU (European Commission, 2025). Addressing the underlying root causes of (in)coherence requires a structured analytical approach, and the categories presented in this framework can therefore provide a valuable foundation for informing these policy discussions.

6 Conclusions

This systematic review demonstrates that achieving policy coherence in European marine and coastal governance is an urgent structural and institutional priority. As climate pressures intensify and human uses of marine and coastal areas continue to expand, the consequences of fragmented and incoherent governance frameworks are becoming increasingly severe. These frameworks are not well suited to address interconnected challenges and often result in ineffective or even counterproductive policy responses.

Drawing on a systematic review of European marine and coastal governance literature, this study identifies persistent institutional barriers that continue to undermine coherent policy outcomes. Key barriers include unclear mandates and roles, insufficient coordination across governance levels and sectors, and fragmented knowledge systems. At the same time, the review identifies important institutional enablers and translates these into actionable policy recommendations. Strengthening coordination across organizational boundaries, developing shared strategies and management processes, investing in harmonized data and knowledge systems, and ensuring inclusive stakeholder involvement emerge as essential conditions for improving policy coherence. The findings further demonstrate that policy coherence challenges are systemic in nature, spanning vertical, horizontal, and geographical dimensions. The persistent divide between land and sea governance, together with the complexity of transboundary coordination, highlights the scale and urgency with which these issues must be addressed.

The archetype framework developed in this study builds on and advances an earlier prototype and provides a structured, multi-tiered and empirically grounded framework to diagnose and address these challenges. By identifying recurring patterns of barriers and enablers, it offers policymakers and researchers a practical approach to move beyond general calls for integration toward targeted and context sensitive interventions. Overall, the typology and findings presented here advance conceptual and thematic understanding of the drivers of policy coherence and provide a foundation for more effective governance of European marine and coastal systems.

Generative AI statement

The author(s) declared that Generative AI was used in the creation of this manuscript. Generative AI was used in the coding of the articles, as states in the methods section. The results have been reviewed and verified by the author(s).

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Footnotes

Edited by: Daniel Depellegrin, Environmental Hydraulics Institute (IHCantabria), Spain

Reviewed by: Liz Skilton, University of Louisiana at Lafayette, United States

Syarifah Aini Dalimunthe, National Research and Innovation Agency (BRIN), Indonesia