Through identifying the progressive chain of events leading to state change, impact, and response, the DPSIR framework and derivatives can potentially be applied to all types of environmental problems. For example, Fock et al. (2011) used PSR to link marine fisheries to environmental objectives concerning seafloor integrity in the German EEZ (Economic Exclusive Zone). Langmead et al. (2007) used mDPSIR to organize information relating habitat change, eutrophication, chemical pollution, and fishing in several European seas. Hills et al. (2013) used DPIVR to assess the impact of, and the vulnerability of marine and coastal ecosystems to, climate change. Lange et al. (2010) used DPSIR to analyse coastal and marine ecosystem changes related with offshore wind farming. Additionally, the framework and its derivatives, have been often used to select and develop indicators for environmental analysis (e.g., Casazza et al., 2002; Andrulewicz, 2005; Rogers and Greenaway, 2005) and inform management decisions (Kelble et al., 2013).

While the DPSIR framework has been used for certain types of problems in the marine environment, the most important aspect is in tackling a set of hazards which, if they adversely affect human assets, economy and safety, become risks to society (Elliott et al., 2014). The hazards may be from natural sources, such as erosion patterns, tsunamis, or isostatic rebound due to geological phenomena. More importantly, from a societal view, they may be anthropogenic such as the over-extraction of material from the sea, the input of chemicals or the building of structures such as windfarms. Human actions may exacerbate the hazards and lead to greater risks such as the removal of a protective saltmarsh or seagrass bed which otherwise could absorb energy and reduce erosion and the consequences of sea-level rise (Elliott et al., 2016). As such those human-induced hazards and risks emanate from activities and thus lead to the pressures as mechanisms resulting in adverse effects unless mitigated; consequently management responses as measures are required to address, mitigate or reduce those hazards and risks.

Each of those risks requires assessment, both cumulatively and in-combination thus requiring a rigorous framework that can accommodate multiple risks. Cumulative threats and pressures emanate from within one activity whereas in-combination threats and pressures arise from multiple activities occurring concurrently in an area. Therefore, once the risks are identified, by determining the source or cause of the threat and its consequences for the marine system, there needs to be a rigorous risk management framework (Cormier et al., 2013) which has to encompass a suite of measures by covering social, governance, economic, and technological aspects (Barnard and Elliott, 2015). This risk assessment and risk management framework thus especially encompasses the DPSIR approach in which the source and causes of risk are the Drivers and Pressures, the consequences are the State Change and Impacts and the risk is managed through the Responses (see Cormier et al., 2013).

DPSIR use has been adopted by and demonstrated to various actors, including research, academia, central and regional policy and decision makers, environmental NGOs, and the wider public. As an example, the EBM-DPSER model for the Florida Keys and Dry Tortugas is the agreed outcome of the joint efforts of over 60 scientists, agency resource managers, and environmental non-governmental organizations (Kelble et al., 2013). Various central administration bodies in Europe have used or are using the framework including, for example, the EEA, UNEP, and the Black Sea Commission (e.g., CLIMBITZ and BS-HOTSPOTS projects). UNEP used the framework as the base for organizing its State of the Environment assessment report (UNEP/MAP., 2012) by including an overview of major drivers in the Mediterranean, an analysis of the pressures, state and known impacts associated with each of the issues addressed by the Ecosystem Approach Ecological Objectives as well as major policy responses. Environmental NGOs have used the framework to present the main issues and to focus their need-for-change message to both the public and policy makers (e.g., WWF, MEDTRENDS project). Despite this, the level of detail depicted in these mostly conceptual applications of the DPSIR framework varies greatly. Most of the publications and projects included in this review do not go beyond the conceptual level although some of the conceptual models do include more details and/or more levels (e.g., Atkins et al., 2011). While O'Higgins et al. (2014) and Scharin et al. (2016) use the framework as a tool to analyse the relationship between human activities and their Impacts or to capture the information needed for marine management, Pettersson (2015) presents a case around eDPSIR and the Port of Gothenburg that includes development of indicators for factors influencing biodiversity and for the assessment of biodiversity itself. Pastres and Solidoro (2012), for the Venice lagoon, emphasize the importance of adopting a DPSIR approach to monitoring strongly supported by modeling tools and mathematical models as these can provide quantitative links between Pressures and State/Impacts. Furthermore, Cook et al. (2014) use detailed conceptual models (EBM-DPSER) together with expert opinion and matrix analyses to explore the direct and indirect relative impact of 12 ecosystem pressures on 11 ecosystem states and 11 ecosystem services.

It is emphasized here that there is a widespread and increasing usage of DPSIR-type conceptual framework models in management and issue-resolving. Although many papers are conceptual, there are more case studies over time either used to describe an issue, thereby communicating a problem with an emphasis on the P-S link, where the natural scientists can apply a high degree of detail, or give the framework entirety across the whole cycle, solving problems through management with more involvement of social scientists, but less detail on the P-S links. In a more restricted study, Lewison et al. (2016) noted that only eight of the 24 DPSIR articles that they reviewed actively engaged decision-makers or citizens in their research, thereby completing a full cycle or involving all stakeholders. Bell (2012) emphasized that the challenge for DPSIR is to be both a precise Problem Structuring Method and of wide use to stakeholders.

It is of note that the analysis here clearly shows that the use of DPSIR is primarily European-based, also noted in the Lewison et al. (2016) review, with surprisingly sparse use elsewhere such as in the USA. This should not necessarily be regarded as a less-holistic or integrated approach to environmental issues, although it may be the result of the European framework directives guiding sustainability becoming increasingly complex, inclusive and integrated with respect to ecosystems, humans, and their activities (Boyes and Elliott, 2014). However, driving the European use is not just the institutional organizations of the EU, but also growth through parallel and sequential funding of European projects supporting those EU framework directives, that have used DPSIR as a central pillar in environmental problem-framing. As indicated above, it has been recognized as a valuable problem structuring method, both within scientific circles as well as its adoption by international organizations. It is perhaps less surprising that there is less use in fully marine systems than in coastal systems, where there are greater populations and environmental problems. In our comprehensive review, only 26 studies covered exclusively marine habitats and from these only eight illustrate concrete case studies. It is expected that in future more studies will focus on fully marine ecosystem due to the further implementation of the European Marine Strategy Framework Directive (2008/56/EC) and the European Marine Spatial Planning Directive (2014/89/EU).

The wide variety of derivatives is shown in their evolution over time in Figure 1C. Most of the frameworks derive directly from DPSIR after 1999, although the DPSEEA-eDPSEEA branch used primarily in health/medicine appeared to diverge earlier. There is some differentiation in use between social sciences and natural sciences, although theoretically DPSIR and close derivatives should cover both types of science. However, more emphasis may be on one or the other depending on the use, where natural scientists may have stronger emphasis on the pressure/state side and the social scientist may have greater emphasis on the impact/response/drivers side. This emphasizes the singular essence of using the DPSIR framework and derivatives in its holistic treatment bridging natural and socio-economic systems and in being a common framework applicable to human and environmental health.

The large number of derivatives indicates that use is wide-open to interpretation and our experience has shown that even specifically within DPSIR there is a high degree of variation in how the major components are interpreted or defined. It thus becomes necessary to define how it is used in every study otherwise there is great confusion in whether a component is ascribed to driver/pressure, pressure/state, or state/impact (Wolanski and Elliott, 2015; Scharin et al., 2016). Under the DPSIR framework (EEA, 1999), there has been longstanding variation in the interpretation and use of various components Drivers-Pressures-State change-Impact-Response, in particular in relation to the P, S, and I components. For example, the term “pressure” is commonly used interchangeably with “activity” or Driving force (Robinson et al., 2008). Similarly, state change and impact are both commonly used in the context of impacts on the environment (Eastwood et al., 2007) whereas impact also commonly refers to the impact on society brought about by a state change to the environment (Atkins et al., 2011). This issue is highlighted by Martins et al. (2012) who also noted variation in the use of indicators between studies (in a fisheries context) as a direct result of this misinterpretation. Whilst there are multiple matrices of the links between sectors, activities and pressures, this has not been carried through to the links between pressures and state changes, state changes and impacts and pressures and impacts, probably due to the large number and complexity of these interactions. Most importantly, the links have not been quantified but remain mostly at the conceptual level.

The recent developments within and between recent EU funded projects (see above), often through their common membership by participants, has helped to standardize definitions and component lists and has given a more rigid structure in starting from concepts and moving to assessments, even though they may have used different definitions.

It is emphasized that the concept of DPSIR is well-illustrated to be sound in that it presents a logical, stepwise chain of cause-effect-control events that describe the progression from identification of a problem to its management. However, its application requires a deeper understanding of the relationships between the different DPSIR components (Bell, 2012) before the concept can be effectively applied and its limitations need to be acknowledged. For example, P-S-I components are not mutually exclusive, despite being commonly treated as such. In particular, the P and S components are strongly linked in that Pressure, as the mechanism of change, causes a number of physical state changes that ultimately lead to biological change (hence the variation in the interpretation of that described by the P, S, and I components), or it can cause immediate biological change. The timescale over which this change occurs is variable and, in dose-response terms, can be chronic (subtle over long time periods) or acute (immediate). However, a discrete classification of pressures and state changes does not acknowledge this (Niemeijer and de Groot, 2008; Svarstad et al., 2008) and therefore overlooks an important part of the process leading to state change. Whilst activities are linked to both the D and P components, DPSIR in its current form does not categorically address activities or follow the pathway through pressure, state change, and impact, thus not adequately illustrating clear cause-effect relationships (Carr et al., 2007), which makes it difficult to pinpoint management actions. This problem has been overcome by the DAPSI(W)R(M) model (Wolanski and Elliott, 2015; Scharin et al., 2016), at the top of the “evolutionary tree” in Figure 1C, where these relationships are inherently contained with a good balance between natural and social aspects.

The DPSIR approach has to reflect the increasing knowledge of the complexity in the system. It is widely acknowledged that multiple activities occur simultaneously and create in-combination effects, that a single activity can give rise to multiple pressures (termed cumulative effects), that a pressure may not necessarily lead to a state change or impact, that a pressure associated with one activity may act differently to the same pressure associated with another activity and that the severity and the potential for state change may differ (Smith et al., 2016). Hence, it will be regarded as being oversimplified if DPSIR focuses on one-to-one relationships, disregarding the complex interactions between multiple pressures, activities, the environment, and society (Niemeijer and de Groot, 2008; Svarstad et al., 2008; Atkins et al., 2011; Tscherning et al., 2012). This can prevent early detection of state changes and impacts and therefore prevent timely, targeted management. Bell (2012) argued that targeted research was necessary to improve understanding of the S and I components of DPSIR (i.e., the state of the environment and its links to social and cultural drivers and impacts on society).

It has recently been concluded that the DPSIR approach and its terms have several anomalies and flaws which require it to be revised (Wolanski and Elliott, 2015; Burdon et al., 2015; Scharin et al., 2016). The main discussion is given elsewhere (see for example, Wolanski and Elliott, 2015; Scharin et al., 2016) but in brief, this contends that the terms require more accurate definition. Furthermore, the DPSIR framework does not categorically refer to the human activities which give rise to pressures. The most recent proposal to optimize the DPSIR framework for environmental management (DAPSI(W)R(M)) (pronounced “dapsiworm”), gives a more accurate and complete indication of the DPSIR framework (Wolanski and Elliott, 2015; Scharin et al., 2016, defined in Figure 1B). The original components of DPSIR, and their definitions, are retained but clarified by the inclusion of activities within the framework (Figure 3). The term Driver thus needs to refer to the basic human needs such as food, shelter, security, and goods. In order to obtain these, society carries out Activities (fishing, aggregate extraction, infrastructure building) which in turn create Pressures which are defined as the mechanisms whereby an Activity has an effect, either positive or negative. These effects, when on the natural system (the physico-chemical and ecological system) then need to be referred to as State Changes to separate them from State, a description of the characteristics at one time. These State changes thus encompass alterations to the substratum, the water column and their constituent biota.

Once these effects occur on the natural system then society is concerned that there will be a resulting change on human welfare and on the ecosystem services which ultimately produce societal benefits (Turner and Schaafsma, 2015). Hence, this Impact is on the human Welfare. Those Impacts on human Welfare and State Changes on the natural system then need to be addressed using Responses. As the EU Directives refer to these responses as Measures then we can use the final term as Responses (using Measures). Those measures then include economic and legal instruments, technological devices, remediation agents, and societal desires (Barnard and Elliott, 2015).

Although as indicated above, DPSIR cannot remain merely a very good concept dealing with a single driver/activity/pressure, given that ecosystems are rarely affected in this single mode and, from the point of view of effects on State Change, a single activity may cause more than one pressure (or mechanism of pressure) or multiple activities might cause a similar single pressure. Further difficulties may exist with different levels of the same pressure from different activities or differing activity spatial or temporal (timescale) footprints in a defined area. At another level, an impact from several pressures or activities might require a single or integrated response or measure. However, this has been recognized and there have been a number of developments to try and deal with more real-world and complex systems. Atkins et al. (2011) used the first nested-DPSIR approach where their marine case study area had many activities that required multiple DPSIRs nested to provide a more holistic view of complex ecosystems. The individual activity DPSIRs could be grouped with their Response components linked within one common Response area, which would comprise an integrated management plan of the case study area. Scharin et al. (2016) have also used this approach in a Baltic Sea case study with the more-evolved DAPSI(W)R(M) framework, where different sectoral activity chains each produce a state change where their sum total is the current state of the ecosystem. They also re-grouped the activities chains around Response to propose an integrated management plan. DAPSI(W)R(M) also can be nested spatially and sequentially, for example across ecosystem boundaries from a river catchment area through an estuary into the sea. Dolbeth et al. (2016) also used the Atkins et al. (2011) approach with nested DPSIR cycles grouped around a central management response, but with possible interactions between the different independent activity cycles and also beyond single area ecosystems at a pan-European level for lagoonal ecosystems. Smith et al. (2016) have also taken the Atkins et al. (2011) concept forward by rotating common grouped DPSIR cycles around a common pressure (for example seabed abrasion caused by individual DPSIR cycled marine activities) and then building up a three dimensional picture of an area affected by many different pressure cycles. All these developments have shown the adaptability of a simple DPSIR concept to a more complete ecosystem approach.

The essence of any framework which is to be successfully and widely applied is that it should be adaptable and, as emphasized here, have an ability to deal with generic and site-specific problems. It must encompass the inherent complexity and connectivity in all environments but especially marine, estuarine, and coastal systems. That adaptability resulting from complexity has been described by Gregory et al. (2013), using terms more common in social rather than natural sciences, as the need for the use of Problem Structuring Methods (PSMs) which enable us to learn from Complex Adaptive Systems (CAS) theory. In particular, both in general terms and specifically for marine environmental management this then encompasses and tackles what are regarded by social scientists as “wicked problems,” a particular challenge in marine systems (Jentoft and Chuenpagdee, 2009; Gregory et al., 2013). While such “wicked problems” have been long-acknowledged in social sciences (Rittel and Webber, 1973), and regarded as problems that are “difficult or impossible to solve because of incomplete, contradictory, and changing requirements that are often difficult to recognize” (https://en.wikipedia.org/wiki/Wicked_problem), they are only now being acknowledged in the natural sciences. Here, we emphasize that we do now have the approaches, framework and background to tackle those problems.

The analysis here has emphasized that, based on a long and extensive use, the DPSIR framework, its large number of derivatives and its recent expanded derivative DAPSI(W)R(M) has the potential as a holistic and valuable tool for analysing cause-effect-response links, determining management measures and communicating these aspects as long as it is used in its entirety. It is required to cover the complexity of coastal and marine systems, the competing and conflicting uses and users and their effects and management but in particular all steps from identifying the source of the problems, their causes and consequences and the means by which they are addressed. It has the potential as a visualization tool for complex interactions and so is valuable for the many stakeholders involved in managing the marine system.

The framework also has the flexibility to be applied across many systems and geographical, it can link marine systems and it can show the connectivity between adjacent systems. In particular, it shows the way in which environmental management is not only embracing complex systems analysis but is very well suited to it because of the many competing aspects. Similarly, to be effectively used it requires effectively merging natural and social science and cooperation between natural and social scientists and thus requires multi- and cross-disciplinary approaches. Hence, it has the ability to solve what may be the seemingly “wicked problem” of integrated marine assessment and management, but with the proviso that we need to keep moving from conceptual and generic models to those which are specific and quantified.