A framework linking ecosystem services and human well‐being: Saltmarsh as a case study

1. The ecosystem services approach is based on the interdependencies between na ture and human well‐being. However, while the ecosystem services aspect of this approach is


| INTRODUC TI ON
The ecosystem services approach refers to the interdependencies between nature and human well-being (Schleyer, Lux, Mehring, & Görg, 2017;Steger et al., 2018). A wealth of research has addressed the challenge of applying the ecosystem services approach empirically (e.g. Burkhard, Petrosillo, & Costanza, 2010;Fisher, Turner, & Morling, 2009) and several definitions and classifications have been developed (e.g. Beaumont et al., 2007;Fisher et al., 2009;de Groot, Alkemade, Braat, Hein, & Willemen, 2010). Whereas the ecosystem services aspect of these classifications is well-developed, the human well-being aspect is still vague. There is a need to clarify and operationalise the links between nature and human well-being, to facilitate embedding of human well-being in policy and decisionmaking worldwide (e.g. UK What Works Centre for Wellbeing; Global Happiness Council; World Happiness Report -Helliwell, Layard, & Sachs, 2016).
Human well-being is a multi-dimensional concept, with various interpretations and no universally accepted definition (Dodge, Daly, Huyton, & Sanders, 2012), which in part explains the challenges in linking it to ecosystem services. Human well-being refers to positive physical, social and mental conditions, not just the absence of negative circumstances such as disease (Summers, Smith, Case, & Linthurst, 2012;WHO, 1948). Human well-being includes both objective dimensions such as level of wealth (economic) and air quality (environmental), and subjective dimensions such as self-reported life satisfaction (OECD, 2011). Two main approaches of objective well-being have been documented that derive from the field of economics. The first is the Basic Needs approach, developed by Max-Neef (1991), which attempts to classify the minimum needs, health and autonomy, that must be satisfied for long-term well-being (e.g. Reinert,2015). The second is the Capabilities approach developed by Sen (1993), which recognises the importance of a person's ability to do the things they want to do (capabilities), as well as achieving those things (functionings) (e.g. White, Imperiale, & Perera, 2016).
There are also two general approaches to subjective well-being derived from the field of psychology: one that focuses on positive feeling, pleasure or hedonia and one focusing on positive functioning, personal fulfilment or eudaimonia (Longo, Coyne, & Joseph, 2017).
Alongside these approaches, many indices and classifications of well-being have been developed, such as The Human Development Index (UNDP, 1990), Well-being of Nations (Prescott-Allen, 2001), Gross National Happiness (Ura, Alkire, Zangmo & Wangdi, 2012) and Scales of General Well-being (Longo et al., 2017). Despite these advances, human well-being remains an elusive or abstract term for some, it is not currently traded as a market commodity (Batavia & Nelson, 2017;Garcia Rodrigues et al., 2017) and quantifying it accurately remains a challenge (Breslow et al., 2016;Fish, Church, & Winter, 2016 Diaz et al., 2015). Of these, only the UK National Ecosystem Assessment Follow-On framework attempts to provide a link, the additional category of 'benefits', between ecosystem services and specific constituents of human well-being. The importance of distinguishing between services (means) and benefits (ends) is now widely accepted (Boyd & Banzhaf, 2007), with benefits defined as the actual contributions made to human well-being (Fisher et al., 2009). Benefits ('good things') and disbenefits ('bad things'; often referred to as 'disservices') derive from ecosystems which different people value positively or negatively (Ostfeld & Keesing, 2017;UKNEA, 2011). It is the benefits and disbenefits that provide a direct link between ecosystem services and human well-being.
Benefits and disbenefits are a product of the interaction between nature and the other capital inputs to generate positive or negative human well-being (Fish et al., 2016;UKNEA-FO, 2014).
The five capitals are: (a) natural, that is, elements of nature that directly or indirectly produce value to people, such as ecosystems and natural processes (UK Natural Capital Committee, ); (b) social, for example, trust, cooperation; (c) human, for example, knowledge, skills; (d) built, for example, infrastructure, equipment; and (e) financial, for example, monetary currency (Fish et al., 2016;Maack & Davidsdotirr, 2015). For example, currency expenditure is often needed to visit natural places and carry out outdoor recreation activities.
Despite the addition of the 'benefits' category and the presence of human well-being in some ecosystem services frameworks and classifications, the majority of the emphasis has been placed on the ecological functions and ecosystem services. There are five key reasons why human well-being remains poorly understood in the context of the ecosystem services approach: (a) there are complex frameworks that do not mention human well-being (e.g. The
Elucidating these linkages has become urgent as policy is increasingly emphasising nature's role in human well-being, for example, The UN Sustainable Development Goals, The Well-being of Future Generations (Wales) Act 2015. This paper has two main objectives: (a) to provide an extended framework that links ecosystem services and human well-being; and (b) to operationalise the framework by conceptually applying it to saltmarsh habitat. Saltmarsh was selected as it is one of the most productive, albeit threatened (Kirwan, Temmerman, Skeehan, Guntenspergen, & Fagherazzi, 2016) and declining global habitats (Silliman, 2014) providing valuable, yet little understood, ecosystem services to humans. The proposed framework addresses the five above mentioned reasons for why human well-being remains poorly understood in the context of ecosystem services. The extended framework is described in Section 1.1. Section 1.2 explains the selection of the saltmarsh case study and operationalises the framework. The supporting information summarises the ecosystem services, benefits, disbenefits and links to human wellbeing from saltmarsh. Section 2 discusses the framework's implications for policy and practice, as well as its limitations; and Section 3 provides conclusions.

| A framework linking ecosystem services and human well-being
To conceptualise our understanding of the links between nature and human well-being we propose a framework that builds on the UK National Ecosystem Assessment-Follow On framework by (a)

| Operationalising the framework: saltmarsh as a case study
The framework is tested on saltmarsh habitat with the aim of strengthening the definitions and framework, ensuring that it is fit for purpose and applicable, and also to improve understanding of the nature-human well-being linkages in this habitat. Saltmarshes are F I G U R E 2 Global distribution of saltmarsh habitat (Data source: Mcowen et al., 2017) areas vegetated by herbs, grasses or low shrubs (Adam, 1990), typically located at the boundary between land and sea and dominated by tidal hydrodynamic forces. They are key habitats for estuarine biodiversity, with high primary production, supporting many species and providing space for shelter, feeding, mating, nurseries, reproduction and migration (Caçador, Caetano, Duarte, & Vale, 2009;Vinagre, Cabral, & Caçador, 2008).
Saltmarshes are a global habitat that flourishes particularly in temperate regions ( Figure 2) (Silliman, 2014). Mcowen et al. (2017) report almost 351,000 saltmarshes globally across 99 countries for a total of approximately 5.5 million ha. Although in the past these habitats were seen as wastelands, they are now widely recognised as among the most productive ecosystems on earth (Silliman, 2014) and provide a range of valuable ecosystem services. Ecosystem services include nursery habitats for fisheries species (Kneib, 1997), sequestering 'blue carbon' (Himes-Cornell, Pendleton, & Atiyah, 2018) and acting as effective natural coast flood protection (Möller et al., 2014). Thus, these habitats are an essential part of countries' economy and culture.
Despite the valuable services provided by saltmarshes, they are highly threatened by human disturbances, including: eutrophication, land use change, pollutants including oil spills, altered hydrologic/sedimentologic patterns, invasive species, and climate change effects, including sea-level rise and extreme weather events (Gedan, Silliman, & Bertness, 2009;Kirwan et al., 2016;Silliman, 2014). Saltmarsh has been found to be declining around the world, having lost between 25% and 50% of their global historical coverage (Crooks, Herr, Tamelander, Laffoley, & Vandever, 2011;Duarte, Dennison, Orth, & Carruthers, 2008). Given their position on the land-sea interface, their provision of diverse ecosystem services at different scales, and unclearly defined links to human well-being, saltmarshes are thus an ideal habitat to operationalise this framework. There is also a tangible need for information on the broader human well-being implications of these threatened habitats to enable their effective and sustainable management.
It is recognised that the links between ecosystem services and human well-being can be complex, are often subtle, and frequently understudied; so this study has focused on the main direct links. The benefits and disbenefits from saltmarsh, and their links to human well-being, are detailed in the supporting information and summarised in Table 2. None of the benefits or disbenefits affected all human well-being domains. The most prominent human well-being domains, that is, those with most linkages, were health (11), connection to nature (7) and living standards (7). The human well-being domains with fewer linkages, in part due to unavailable data and  (8) and living standards (6). Linkages between disbenefits and human well-being were few, influenced by a historically, greater literature focus on benefits compared to disbenefits (Ninan & Inoue, 2013;Sandbrook & Burgess, 2015). This study evidences that grey literature and informal sources need to be considered to obtain evidence for understudied (dis-) benefits from ecosystem services and their links to human well-being.
There is more information and understanding available for some There is even less information and understanding available for disbenefits, which highlights it as an overall area for future research.
Particularly, further investigation is needed to understand the links, if any, between disbenefits and human well-being, particularly on social cohesion and spiritual and cultural fulfilment, for which no links were identified.

| Scale, impact and relevant parties
It is important to note that not all benefits and disbenefits accrue homogeneously to all parties, that is, with the same impact on human well-being (positive for benefits or negative for disbenefits) and in the same spatial scale. They are heterogeneous in space and evolve through time (Fisher et al., 2009;Luisetti et al., 2011), and as a result the accompanying human well-being effects will also vary. Thus, Figure 3 was developed as a generic, unidimensional characterisation of saltmarsh (dis-) benefits and human well-being by three key parties, spatial scale and impact on well-being. Figure 3 is not aimed at representing a specific saltmarsh but to exemplify the importance and potential variability of scale and impact of (dis-) benefits on different parties. We recognise that a location-specific application will be context-dependent involving a complex three dimensional view of (dis-) benefits and well-being. Nevertheless, this diagram evidences some important findings, such as farmed foods can be a benefit to residents, visitors and further afield up to the national level with a mid-range impact. While, equable and favourable climate is an ex-situ benefit at the regional to global level with low impact. Figure 3 also provides examples of potential temporal shifts due to climate change or management efforts. For instance, the transmission of diseases via mosquitoes has rarely been reported in the UK but studies expect this to change with increased marsh creation to mitigate climate change (Medlock & Vaux, 2015).
Notably, most disbenefits accrue at the local scale with a low impact on residents or visitors actually on or near a saltmarsh. These F I G U R E 3 Generic diagram of benefits and disbenefits and human well-being of saltmarsh by party, spatial scale, impact on well-being; dotted upward arrow = future potential temporal change and living standards, but large scale benefits are often linked to safety and security. However, the (dis-)benefits and human well-being domains include several differing sub-categories. For instance, wild food can refer to local resident groups foraging for Samphire, but also to commercial fisheries that are sold locally and ex-situ. In this example, wild food foraging is linked to social cohesion with a low impact and commercial fisheries are linked to living standards with a high impact.
These findings have implications for the management of saltmarsh as very different policy decisions will be made if only the local scale is taken into consideration, or if only the national to global scale is considered.

| D ISCUSS I ON
The implementation of the framework provides a promising pathway for future research and raises a number of novel considerations and implications for policy and management.

| Improving the nature and human well-being linkages: Implications for policy and management
Whilst policy documents are increasingly taking human well-being into account, linking it to nature is still in its infancy (Science for Environment and Policy 2018). Understanding the biophysical, social, economic and political settings where disbenefits can be effectively mitigated, and benefits increased through ecosystem management is shown here to be crucial for enhancing human well-being. Through the explicit and structured clarification of the linkages between ecosystem services and human well-being, our proposed framework provides an improved understanding of the potential implications of ecosystem changes. This framework thus provides a means to incorporate the voice of other sectors, particularly health and social services, directly into environmental management to provide more holistic and informed decision-making considering the impacts on human well-being.
The framework also improves accessibility to the complex research area of human well-being. The many definitions and classifications which are attributable to human well-being can be a barrier to its inclusion in policy and management. Arguably, this challenge has been insufficiently considered to date and there is a clear gap in our understanding (Ninan & Inoue, 2013;Shackleton et al., 2016).
The proposed framework is helpful for researchers to identify interdependencies between services and (dis-) benefits, and identify trade-offs with specific impact on human well-being at different scales and for different parties. Without consideration of the full suite of human well-being domains, policy and management risk overlooking a wide range of human well-being implications, potentially leading to inefficient trade-offs.
In the context of saltmarsh (and other coastal habitats), this framework could serve as a useful tool to guide policy and management decisions in practice. This is particularly pertinent in the light of recent policy aspirations, whereby human well-being appears to be rising-up the political agenda in certain countries. For instance, Wales (UK) is the first country to introduce legislation that places a statutory duty on all public bodies to align with nationally specified human well-being goals (Wellbeing of Future Generations (Wales) Act 2015). The conceptual framework developed through this research could support initiatives as described above, and its reach extends beyond the UK setting. At the international scale, the UN Sustainable Development Goals explicitly recognise the need for equitable access to health and human well-being in the pursuit of sustainable futures (UN, 2015). This arguably requires the inclusion and integration of human well-being within the management of social-ecological systems, to which this framework provides a valuable stepping stone. It also has potential to provide a valuable contribution to global saltmarsh management, for example, by informing the RAMSAR Convention.
More specifically, the framework can serve as a means of engaging relevant stakeholders in decision-making processes, to better understand perceptions of (dis-)benefits and human well-being, and how these vary with different perspectives. In participatory processes, this framework could help policymakers to negotiate and manage potential trade-offs and dichotomies between (dis-)benefits and human well-being to reach socially acceptable outcomes and enhance the legitimacy of the process (Alexander, Doorn, & Priest, 2017). For instance, in the case study the trade-off of employing saltmarsh for different benefits is evident, for example, military and industrial use prevents use for recreation or farmed food. Regarding dichotomies, saltmarsh plant pollen can support pollinators of neighbouring farm land but it can also be a disbenefit, causing allergies.

| Limitations and recommendations
Although the concept of ecosystem services has become increasingly embedded in the management of social-ecological systems, the approach itself is not without extensive criticism (e.g. Jadhav, Anderson, Dyer, & Sutton, 2017), especially when it involves monetary valuation (e.g. Gómez-Baggethun & Ruiz-Pérez, 2011). Thus, a risk could be that the framework leads to a reductionist approach, particularly if the framework is operationalised through limited, monetary indicators. Another risk is that due to the many different management sectors often involved in ecosystem management, it might be very difficult to ensure an integrated approach. Thus, this framework would benefit from being applied with a holistic view, including qualitative and quantitative values to derive weightings, and carefully considering the trade-offs of (dis-)benefits at different spatial scales, levels of impact and for different parties.
While the framework has been validated through its application to saltmarsh, others are encouraged to subject the framework to further scrutiny and application to other habitats to investigate commonalities and differences in the linkages and relationships reported here. A next step in the framework development, depending on the management objective, could be for relevant stakeholders to further delineate the benefits, disbenefits and measures of human well-being through solution-oriented participatory approaches, for example, wild food could be divided into commercial and non-commercial. Exploring the success of transferability to other habitats and specific cultural contexts will be key in the continued development of the framework. Whilst further research is required, this framework represents an important stepping stone for advancing holistic assessments of human well-being in future ecosystem services research.

| CON CLUS IONS
The proposed conceptual framework enables the greater inclusion and understanding of the human well-being effects from nature. This is achieved particularly through the holistic approach of con- The useful application of the framework using a case study habitat highlighted knowledge gaps for saltmarsh habitat; as well as the potential applicability and usefulness of the framework. The application evidenced that saltmarsh benefits mainly accrue at larger scales with a greater impact (e.g. reduced hazard risk) affecting local to global individuals, while disbenefits tend to occur at a smaller scale and impact affecting in-situ individuals. There are also potential temporal shifts in impact of (dis-)benefits due to climate change or management efforts that need to be considered. Previous literature has struggled to account for the human well-being attributes of saltmarshes in a structured and objective fashion, and this approach overcomes this barrier, resulting in the first comprehensive assessment of the human well-being domains associated with saltmarsh.
There is a need for further research into the links between benefits and disbenefits and understudied human well-being domains, particularly life satisfaction and happiness, social cohesion and spiritual and cultural fulfilment. It is also recommended that the framework be further applied across a range of scales and habitat types to enable its continued development and transferability. The proposed framework is a valuable stepping stone providing a structured approach to improving understanding of ecosystem services, benefits and disbenefits and human well-being linkages.

CO N FLI C T O F I NTE R E S T
The authors do not have any conflict of interest.

DATA AVA I L A B I L I T Y S TAT E M E N T
No data were used in writing this paper.