1. Introduction
Nature-based solutions (NBS) are acknowledged by the European Union as a potential opportunity for mitigating hydro-meteorological risks, such as flooding, landslides, coastal erosion, and heatwaves. After decades of anthropogenic modification of ecosystem functions, scientists have cautioned that we are gradually approaching a point where the collapse of ecosystems and the services that they provide is inevitable, e.g., for river system in Wantzen, et al. [
1]. In the past, large-scale engineering measures have been implemented in riverine and mountain areas to mitigate the potential destruction of property and loss of life caused by natural hazards as a result of hydro-meteorological risks. Unfortunately, these massive interventions can have negative impacts on the natural environment [
2], as well as not being capable of completely mitigating risks but rather transferring risks to other geographical areas, and in some cases, increasing or creating new risks and vulnerabilities for biodiversity and communities [
3].
Since the late 1980s, nature itself is increasingly being perceived as a means to mitigate risks. In 2009, the ecosystem-based landscape planning and resource management flourished, and in 2011, the term “green infrastructure” was well-established to define the network of natural and semi-natural areas, which contribute to ecosystem health and benefits for human. NBS is an umbrella term for solutions based on natural processes and ecosystems solving societal challenges [
4]. NBS are understood as ‘solutions that are inspired and supported by nature, which are cost-effective, simultaneously provide environmental, social, and economic benefits, and help build resilience. Such solutions bring more and more diverse, nature, and natural features and processes into cities, landscapes, and seascapes, through locally adapted, resource-efficient, and systemic interventions.’ [
5]. NBS are ‘nature-friendly’ solutions with high biodiversity requirements [
6].
Nature-based solutions are green and blue solutions but may integrate engineering elements, too [
5]. While gray solutions are mostly mono-functional, NBS can serve as multi-purpose and flexible alternatives for various objectives, address multiple goals, and create co-benefits, such as risk reduction, enhancement of cultural uses, improvement of ecological quality standard, and green economy reinforcement [
7,
8]. The European Union (EU) is positioning itself as a leader in ‘innovating with nature’ [
5] and has set NBS design, implementation, and monitoring at the top of its political agenda. This has resulted in the funding of a large number of research projects [
5,
9], such as NATURVATION (
www.naturvation.eu), RECONECT (
www.reconect.eu/), PHUSICOS (
www.phusicos.eu/), and ThinkNature (
www.think-nature.eu). The goals of the current EU research and innovation policy agenda on NBS are based on major strands of knowledge and build on results from the past EU framework programs. Many of the H2020 EU funded action projects follow a similar strategy, namely to optimize and upscale NBS using EU financial support and providing governance support to enhance collaborative planning, including co-creation processes. Furthermore, recent studies have identified that partnerships and collaborative governance models are crucial for successfully implementing NBS [
10,
11] and that missing intersectoral collaboration causes bottlenecks when implementing measures [
12].
Nature is considered as a public good that historically cannot be managed or sustained solely by private or market actors. Consequently, stakeholders with governmental power have aimed to control nature using a top-down approach to governance [
13]. However, observations from federal or decentralized systems, such as in the US, have shown that solutions to cross-jurisdictional problems can be addressed more efficiently through decentralized and contractual agreements [
14]. In recent years, environmental governance has shifted from a top-down approach to collaborative planning [
15]. Polycentric governance structures have evolved and are described as systems in which decisions are taken through formally independent decision-centers [
16]. Polycentric governance structures, which include a large spectrum of stakeholders, are assumed to be more effective in the management of public goods than traditional top-down approaches to governance [
17,
18]. Furthermore, NBS governance analysis already indicates that NBS implementation has successfully resulted from such a co-creation with a large diversity of stakeholders [
19]. However, observations of cases have shown that the “the more, the better” principle cannot be applied to increase success in participative planning [
20]. Inter-sectorial communication needs to be efficient [
12], and the relevant stakeholders have to be on board [
21,
22].
In the EU, the Parliament and the Commission are currently strongly encouraging—at least as part of the research funding policies—innovative models for collaboration, such as Living Lab, to create solutions, and the involvement of stakeholders and end-users in the design and implementation of NBS has an important role to play [
5]. Based on Leminen’s definition in 2013 as cited in Fohlmeister, Zingraff-Hamed, Lupp and Pauleit [
21], “A Living Lab is a physical region and interaction space, in which stakeholders form a quadruple helix innovation network of companies, public agencies, universities, users, and other stakeholders in the pursuit of collaborating for the creation, prototyping, validating, and testing of new technologies, services, products, and systems in real-life contexts” [
23]. The efficiency and the legitimacy of the participatory process are critical for the quality of the resulting solutions. Stakeholder participation can take many forms, ranging from information and consultation to partnership and collaboration to citizen power [
24,
25,
26]. While informative and participative planning can help to reach acceptance, co-creation also aims to achieve multiple benefits for society by involving a broad spectrum of stakeholders not only in the planning but also in the design, implementation, monitoring, and evaluation as well as the maintenance stages of projects [
16,
21].
To ensure a well-functioning co-design process and to deal with potential conflicts, issues, and constraints that may arise, identifying and addressing stakeholder values, interests, and knowledge is a crucial step in the NBS process [
27]. While some theoretical approaches request certain stakeholders and their perspectives can contribute the most [
28], other approaches strive to involve more different groups continuously during all phases equally [
29,
30]. Innovative approaches to achieving co-creation, such as the quadruple helix innovation networks or Living Lab approaches [
23], provide methodologies for bringing together core stakeholder groups. However, while the number of projects using co-creation increases, and “good” practices related to co-creation have been described, limited attention has been focused on identifying the specific stakeholders needed for the planning, design and implementation, monitoring and evaluation, and maintenance of nature-based solutions [
21]. Often considered self-evident in the literature (Reed et al., 2009), stakeholder-enhanced processes mostly result from self-organization [
31,
32] or from windows of opportunities directly after a disaster event has occurred [
33], rather than from strategic decisions. A lack of process for identifying and involving stakeholders often leads to a very long initiating process and significant delays in implementation. For example, in the case of the Isar river restoration in Munich, it was more than 30 years [
34]. Systematic methods to identify relevant stakeholders seem to be crucial to enable higher planning efficiency, reduce bottlenecks and time needed for planning, designing, and implementing NBS.
According to literature, characterizing stakeholders is useful in order to understand the power relationship between them and their specific interest in the project to avoid pitfalls and failures of such processes [
35]. Some stakeholder typologies exist, [
36], but are based on psychological evaluation of the stakeholders and have a limited potential to support the initialization of a collaborative planning process. These stakeholder characterization methods are more efficient for an ongoing project as a tool for the project manager. Furthermore, while these typologies based on psychological aspects help to identify the role of stakeholders in terms of attributes, knowledge, source of information, and roles in the action arena, they are not specific for NBS for natural hazard mitigation.
In this context, this contribution intends to answer the three following research questions:
Which stakeholders and stakeholder types are or should be part of the collaborative planning process that leads to NBS co-design and implementation?
Do these real-life constellations reflect theories on the ideal structure of co-creation?
How does a systematic stakeholder mapping method support the initiation of participative planning?
The objective of the research is to reflect upon stakeholder constellations, as observed in two H2020 projects, namely PHUSICOS and RECONECT, and the relative methods developed to identify and initiate collaborative planning to co-design NBS. While the PHUSICOS stakeholder selection procedures rely on the quadruple helix innovation networks theories, the RECONECT method relies on the influence of actors perceived by the core stakeholders. The authors have asked that who has the power to influence decisions for NBS and/or is affected by the risks at stake. We stress that this analysis is not meant to generalize conclusions about favorable stakeholder constellations because they are largely case-specific [
19,
37]. However, we wish to draw general conclusions on stakeholder mapping methods and to stimulate the debate on the use of systematic methods to strategically identify relevant stakeholders and initiate co-creation.
2. Materials and Methods
The methodological approach is composed of seven steps (
Figure 1). In order to answer the research questions, we apply inductive and explorative methods for the case study analysis to generate an in-depth, multi-faceted understanding of a complex issue in its real-life context [
38,
39]. In this context, we first identify the case study sites, then collect data on the stakeholders potentially involved in the collaborative planning process. We then apply explorative clustering analysis to map the stakeholders according to the variables identified and assess the mapping procedure according to the theories applied in both research projects.
2.1. Case Sites
The cases’ sites include sixteen NBS (
Figure 2 and
Table 1) for hydro-meteorological risk reduction, which is investigated in both ongoing H2020 projects—PHUSICOS and RECONECT. All cases of the data pool are located in Europe, and NBS has been or is being implemented to manage hydro-meteorological risks, such as flooding, droughts, erosion, avalanches, or landslides. The six cases of PHUSICOS represent five case study sites and two NBS implementation locations in the Pyrenees. Ten cases of the RECONECT have been integrated into the data pool, namely the demonstrator cases that are been established, validated, or monitored during the RECONECT project lifetime. The 15 RECONECT collaborator cases have been excluded from the data pool for the purpose of this article because the degree of implementation is still largely undefined at the time of writing.
2.2. Stakeholder Identification
Stakeholder identification conducted in both projects (RECONECT and PHUSICOS) has followed a similar procedure, i.e., case representatives are interviewed, and interactive and structured worksheets are used to document existing and potential stakeholder involvement in the co-creation process. Despite the few slight differences related to the timeline of the data collection, the comparability of the collected data is high because they follow the same methodology.
The RECONECT research group performed the stakeholder identification between November 2018 and April 2019 by visiting case sites that are at different steps of the design, implementation, and monitoring procedure of the NBS. At each of the case sites, the official partners of RECONECT (e.g., representative of municipalities, water authorities, or universities) are interviewed. Interviewees are asked to complete a number of interactive worksheets in order to capture a range of information about existing and potential stakeholders involved in the co-creation process. Interviewees are asked to identify stakeholders by using a pre-prepared list of stakeholder groups as a way to guide and encourage conversations and reflection as well as ensure the comparability of results. The results of these interviews are documented in a report that is validated by the representatives of the demonstrator sites.
The PHUSICOS research team performed the stakeholder identification shortly after the research project started in April 2018. In order to provide comparable data with the RECONECT cases, the PHUSICOS team performed a second round of stakeholder identification in May and June 2020 by following, as far as possible, the RECONECT methodology. Potential stakeholders are listed based on available information from the different sites with the aid of relevant documentation, including support letters and available protocols from meetings with stakeholders at different sites. The structured worksheets produced by RECONECT serve as a template to collect information on the PHUSICOS cases. At each of the case sites, the official partners of PHUSICOS (e.g., representative of municipalities, water authorities, or universities) are asked to fill in the worksheets using the prepared list of stakeholder groups as a guide. After the interviewees fill in the worksheets, the PHUSICOS researcher in charge of the social science-related work package contacts each partner to validate the results.
2.3. Stakeholder Characteristics
Each stakeholder is characterized according to the five categories of variables (
Table 2):
Belonging: this variable describes the case study site the stakeholder belongs, their institution, as well as which stakeholder group the stakeholder represents. Stakeholder groups represent different sections of society: governmental authorities, political representatives, civil society, private sector, academia and research sector, media, and international and transnational organization. Each stakeholder can only represent one group at a time.
Role of stakeholders: Each stakeholder can have different roles [
40]. The decision-makers make and execute decisions. The implementers are responsible for the execution or implementation. The facilitators coordinate a variety of actors for the design, implementation, and monitoring of measures. The providers of expert knowledge are mostly consultants, universities, insurance companies, as well as local informants from civil society. The funders or sponsors can be private, governmental, or non-governmental, and finance activities and measures. The lobbyists refer to stakeholders or group representatives who attempt to influence decision-making. The mediators or facilitators mediate and facilitate communication between different stakeholders. While stakeholders can only represent one group, it is possible for them to have several roles. Stakeholder roles vary across contexts.
Planning stage: this variable describes the different NBS project steps. The importance of various stakeholders in different steps from design, planning, implementation, monitoring, and evaluating, as well as regular maintenance, can vary. Even when striving for broad involvement of different stakeholders during all phases, this evaluation can help to determine and better understand participants varying motivation to participate and resulting potential different levels of willingness to engage and act, their relative power, influence, and interests during the different stages of such a co-creation process.
Relation to the hazards: It is also important to look at the relation of stakeholders to NBS, different NBS planning processes, and potential offsets and trade-offs. This category aims to differentiate between stakeholders who are affected by natural hazards and those who are affecting natural hazards. For example, stakeholder groups are affected in different ways, and property owners can, for example, be threatened by floods [
41]. On the other hand, individual stakeholders can have the ability to reduce or mitigate natural hazards (e.g., forest owners and their forest management) [
42].
Relation to the NBS: While some stakeholders might be affected by a selected solution to reduce risks, others might not benefit from a measure (e.g., a landowner being expropriated to build a retention basin to protect a village downstream or farmer asked to change land use to enable regular flooding) [
42]. This analysis also helps to determine the ability of different stakeholders to influence the decision on potential NBS or traditional grey engineering solutions. Besides, some stakeholders might not have the power to influence all of the phases but might be influential in the implementation phase, intervene, and halt the implementation of NBS.
2.4. Analysis
According to our methodological approach (
Figure 1), we first describe the potential stakeholder using descriptive statistical methods on qualitative variables. The link between variables is investigated using chi-squared contingency table tests and goodness-of-fit tests [
43,
44].
In order to identify which stakeholders are part of the collaborative planning process that leads to NBS co-creation (first research question), we first perform a descriptive statistical analysis on the variable collected. In order to investigate which parameter influences the role of the stakeholder in the planning process and at which stage the stakeholder is involved, we extend the analysis to a multiple factorial analysis (MFA). MFA is an explorative method that enables to analyze simultaneously sets of variables (continuous or categorical) and linkage between them.
We finalize the statistical stakeholder typological analysis by performing a clustering analysis based on k-means methods [
45,
46,
47].
An original contribution of this paper is to statistically investigate the stakeholder constellation existing in NBS and to compare statistical results to theories on the stakeholder structure of NBS co-creation. The analysis is expanded to qualitative discussion on the role and potential of stakeholder mapping tools, especially to answer both remaining research questions: Do real-life constellations reflect theories on the ideal structure of co-creation? How does a systematic stakeholder mapping support the initiation of co-creation?