Edited by: Sebastian Villasante, University of Santiago de Compostela, Spain
Reviewed by: Ana Isabel Lillebø, University of Aveiro, Portugal; Ulisses Miranda Azeiteiro, University of Aveiro, Portugal
This article was submitted to Marine Ecosystem Ecology, a section of the journal Frontiers in Marine Science
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Coastal waters provide a wide range of ecosystem services (ES), but are under intensive human use, face fast degradation and are subject to increasing pressures and changes in near future. As consequence, European Union (EU) water policies try to protect, restore and manage coastal and marine systems in a sustainable way. The most important EU directive in this respect is the Water Framework Directive (WFD) (2000/60/EC). Objective is to reach a “good status” in EU waters, following a stepwise and guided process. Our major objective is to test how an ecosystem service assessment can support WFD implementation in practice. We use the Marine Ecosystem Service Assessment Tool (MESAT) that utilizes spatial definitions, reference conditions and the good status according to the WFD as well as data and information gained during the implementation process. The data-based tool allows comparative analyses between different ecological states and an evaluation of relative changes in ES provision. We apply MESAT to two contrasting systems in the German Baltic Sea region, the rural Schlei and the urban/industrialized Warnow Estuary. These data-based assessments show how the ES provision has changed between the historic, pre-industrial state around 1880 (reference conditions with high ecological status), the situation around 1960 (good ecological status), and today. The analysis separates the estuaries into water bodies. A complementary expert-based ES assessment compares the situation today with a future scenario “Warnow 2040” assuming a good ecological status as consequence of a successful WFD implementation. Strengths and weaknesses of the approaches and their utilization in the WFD are discussed. ES assessments can be regarded as suitable to support public relation activities and to increase the acceptance of measures. Further, they are promising tools in participation and stakeholder processes within the planning of measures. However an ES assessment not only supports the WFD implementation, but the WFD provides a frame for ES assessments larger scale assessments in seascapes, increases the acceptance of the ES approach and the readiness of stakeholders to get involved.
Estuaries are highly dynamic, unique, and diverse ecosystems (
With respect to environmental quality and restoration of estuaries in the European Union (EU), the Water Framework Directive (
Especially in estuarine ecosystems, the restoration and recovery is complex, follows different recovery patterns as well as rates and the restoration effectiveness differs between the ecosystems (
The potential benefits of ecosystem service assessments for EU policies and WFD implementation are reflected by many studies (
According to the Millennium Ecosystem Assessment (
An awareness of benefits and potential relevance of coastal and marine ES exists, but this is still not adequately reflected in research. Publications on ES have increased exponentially during the last 15 years. However,
While ES assessments in terrestrial urban systems have a long tradition (
For inner and outer coastal waters, the WFD provides a typology, spatially defines water bodies, defines reference conditions (high ecological status) and a good status. It provides comprehensive background and preparatory work, but it has to be explored, how this can be utilized as a basis for an ES assessment in practice. The ES assessment in the context of the WFD in estuaries in general and in industrialized, urban estuaries in particular, is an urgent task. For example, the WFD defines how a good status for coastal and marine habitats should look like from an ecological perspective. However, it is uncertain, what the consequences of this desired good status means for humans and for services provided by these ecosystems.
Objectives of this study are: (a) to apply and test a tool that builds upon the WFD typology and utilizes the European ES MAES standard; (b) to show how a data-based assessment can utilize and support major ideas of the WFD, for example by carrying out comparative relative ES assessments between different ecosystem states (present, good, high/reference conditions); (c) to provide comparisons between water bodies/sub-types within coastal estuaries as well as between urban and rural estuaries; (d) to test an expert-based future scenario assessment; and (e) to critically evaluate the practical use of ES assessment approaches for supporting WFD implementation on the local level.
The rural Schlei Estuary is a brackish water body with a surface area of 52 km2 and a total length of 43 km (
Already in the early medieval, Haithabu (near Schleswig) became a major trading center in the Baltic. During Christianization, population and agricultural areas further increased. With industrialization and the connection to the railroad network, fabrics and fish industry experienced economic upswing. In the 1960s and 70s land consolidation and intensification in agriculture changed the landform. In 2015, 53,366 people lived in the connected municipalities around the Schlei concentrated mainly in Schleswig and Kappeln (
The Schlei can be separated into the inner (near the city of Schleswig), middle and outer (close to the Baltic Sea) Schlei. It is classified as hypertrophic and one of the most eutrophied German Baltic coastal waters (
High freshwater inflow and limited exchange with the Baltic Sea cause strong gradients. The littoral is dominated by reed belts. Other submerged vegetation, e.g.,
The urban, industrialized Warnow Estuary (including Breitling) is surrounded by the city of Rostock, covers an area of 12.6 km2 and has a total length of 14.4 km (
First human settlements date back to the 6th century. In the 12th century Rostock became a Hanseatic city with a peak in prosperity in the 15th century. Industrialization in the 19th century brought an economic upswing. In 1960, the overseas port was opened, leading to a further rise in population, economy and industry. Rostock was shaped by the centrally-planned social and economic system of GDR. After the German reunification in 1990, population and economy first decreased and later increased again. In 2015, Rostock had a population of 206,011 inhabitants and a population density of 1,137 inhabitants per km2 (
The Warnow Estuary has a water volume is 49.6 million m3 with a mean depth of 4.0 m and its deepest point at 14.5 m (shipping channel). It is highly eutrophied and in a poor ecological condition, according to the
For several reasons, an ES assessment in coastal and marine waters is a special challenge compared to terrestrial ecosystems. Terrestrial ecosystems (e.g., forests, fields, urban area) have clearly defined and well visible boundaries, that are largely stable in time. Therefore, the landscape can be subdivided into subsystems. ES can be assessed for each subsystem and compared to each other. Most aquatic ecosystems, like mussel or seagrass beds, are not visible from outside, usually do not have distinct boundaries, and are spatially and temporally variable. Further, the availability of data usually is scarce. On the other hand, the ecology of a water body is relatively homogeneous and defined by major physico-chemical parameters, like depth, tidal range, salinity, temperature, turbidity, residence time, wave exposure and current velocities. In the WFD, these parameters are used for a characterization and classification of all coastal waters, referred to as typology (
Both assessed estuaries are micro-tidal (less than 0.2 m tidal range), have a natural water depth below 30 m and are sheltered with good to moderate water exchange. Therefore, both systems are mesohaline inner coastal waters (type B2) according to the Germany WFD typology (
For each type, the WFD defines reference conditions, which describe the biological quality elements that would exist at high ecological status. It means with no, or very minor disturbance from human activities. Biological quality elements include phytoplankton, macro-algae, angiosperms, benthic invertebrate and fish fauna. If ecosystems with high ecological status do not exist, reference conditions can be defined based on historical data, modeling or expert judgment (
A major idea to adapt the WFD-typology for MESAT was, that coastal waters belonging to the same type show many similarities with respect to ecological properties, structures and processes. This is also true for the historic conditions. We assumed that the provision of several ES today is and in the past was largely similar in coastal waters belonging to the same type. In this case, once a coastal water has been assessed in detail, much of this information could be transferred to another coastal water belonging to the same type. This would make the assessment a lot less time consuming.
We adapted the Common International Classification on Ecosystem Services (CICES, version 4.3) (
The Warnow and the Schlei assessments were done independently by two Master students within a time-period of about 4 months. Both students had a suitable interdisciplinary background and were familiar with the locations. First step in the assessment was the search for suitable information and data for every indicator and the three periods in time: the present state, the years around 1960 and the late 19th century. The data was collected for every spatial sub-system, the WFD water body. In a second step, the data for different periods in time, the late 19th century and the early 1960s were compared with each other and with the present state. For the comparative assessment, we used a relative classification system. It allowed for comparing ES with different units directly and enabled a relatively fast application.
For assessing the quantity of changes, we defined eleven scoring classes. No changes (class zero) and five scoring classes each representing increasing and decreasing service provisions. The class boundaries are non-linear (
The relative scoring system indicates changes between two different periods in time. For example, the score 1, indicating a slightly higher ES provision, is given when the increase in the present state is higher by a factor of 1.1–1.3 compared to a historic state.
We used field, empirical or statistical data, reports and literature, information derived from models and expert knowledge. The data was categorized according to its reliability. These reliability scores were used in
In a second application, we provided a future scenario for the year 2040 for the Warnow Estuary, called “Warnow 2040.” Guiding question was how an ES assessment could support the practical implementation of the WFD. The scenario assumed a hypothetical implementation of the WFD including an improved, moderate ecological and a good hydrochemical status of the Warnow Estuary. In an internal background paper of the year 2015, the authorities responsible for WFD implementation (LUNG-MV, pers. com.) defined ecological targets for the Warnow Estuary, taking into account that the Warnow Estuary is a heavily modified water body and offers only limited possibilities for improvements. The suggested programme of measures included reduced external nutrient loads and a restoration of shoreline habitats. In our scenario, we assumed that negative eutrophication effects like algal blooms or hypoxia do not occur anymore in 2040 and that other environmental directives are implemented as well. Most important is the implementation of the EU Bathing Water Directive (
“Warnow 2040” was sub-divided into one scenario spatially focusing on the northern, outer, industrial and the other on the southern, urban Warnow Estuary. We assumed that these scenarios are realistic and are enabled by WFD implementation and improved ecosystem quality. For the southern scenario, covering the old city harbor, we assumed an innovative, sustainable and maritime development offering a high quality of life. It included seaside housings, green spaces for recreation and public water access, including a beach. The city harbor scenario was based on internal plans of the city of Rostock. It further assumed an implementation of the plans for the national garden exhibition in 2025 and planned subsequent urban developments. For the northern, industrial part of the estuary, the scenario assumed that the deepening of the shipping canal and the harbor extension are realized leading to an increase of industry, construction (shipyard) and services. We assumed that near the seaside resort Warnemünde, maritime tourism and cruise shipping increased. This scenario was based on compiled internal plans of the city of Rostock and the Rostock Port company. The two scenarios were visualized with photographs and maps in a PowerPoint presentation.
The assessment involved 14 scientists with different background as well as 6 experts from different regional authorities, which are responsible or at least familiar with WFD implementation. The assessments were carried out within 4 meetings, face-to-face and via teleconferences. On average, the meetings lasted about 2 h and started with a short introduction including background and objectives, followed by the presentation of the “Warnow 2040” scenarios (altogether about 30 min). After an introduction into the ES assessment tool, the experts were asked to carry out an assessment individually on paper, which took about 35 min. The experts compared both scenarios with the present state of the estuary and scored, based on their perception of the changes, relative differences for each ES class separately using the scoring system shown in
For this assessment, a sub-set of 30 relevant ES classes were pre-selected by the authors, based on MESAT. After the individual assessment, the scores of each expert were entered into an EXCEL sheet. The following discussion gave the experts the possibility to raise questions, settle misunderstandings and, in case, to modify scores. Aim was not to unify the scores and views. Afterward the experts had the possibility to discuss the suitability of the ES and the indicators behind, the approach and the usability of the system within WFD implementation. The discussion on average took nearly 1 h.
Additionally all experts carried out a self-assessment in five classes, ranging from poor to excellent, with respect to geographical knowledge of the Warnow Estuary, knowledge about its ecological state and knowledge about the WFD.
Altogether 31 ES classes were assessed based on 54 indicators. The assessments of the rural Schlei and the urban Warnow Estuary show many similarities. This is especially true for the provisioning and cultural services (
Ecosystem service (ES) classes and underlying indicators based on CICES (
Similar in both systems is the strong increase in cultural services as result of steadily increasing tourism (
Indicators related to the biological elements of the WFD, are mainly reflected within the regulating services. This is why they require special attention. Several regulating services are of high importance and show changes in time and between inner, middle and outer water bodies. The nutrient retention (R1) indicated by nitrogen fixation, burial, and denitrification mostly shows increases. With increasing eutrophication, the burial of nutrient and denitrification increased. These indicators reflect important ecosystem processes. It is questionable if increasing N-Fixation should be counted similarly, because different to the other processes, it adds nitrogen to the system. Therefore, we inverted the score for N-fixation. However, this process is negligible in the Schlei and did not change significantly in time.
Mass stabilization (R3) indicated by extent of emerged, submerged, and intertidal habitats shows a steep decrease between 1880 and today but an increase after 1960. Reason is that many habitats were lost by intensified human use of the Schlei until 1960. Afterward nature protection helped to increase the areas again. Flood protection (R5) covers shoreline erosion rate, maximum depth, needed for maximum wave height calculation, and the flood protection design basis. The Schlei is protected by regional dykes with slightly different heights, because a universal flood protection design basis does not exist. However, the height of dykes during the last decades steadily increased to deal with sea-level rise risks explaining the increase in ES provision.
Nursery grounds (R6) indicated by submerged and intertidal habitats diversity, occurrences of low oxygen concentrations (<6 mg/l), water transparency (Secchi depth), species distribution, nursery areas and total versus protected nursery areas. The changes in time and between the water bodies are limited, but this is a result of contradicting developments and indicator values. Between the 1960s and today Secchi depth declined, but nursery areas and their protection increased. Changes in chemical conditions are mainly a result of increasing eutrophication. As consequence, the phytoplankton primary production increased. This causes a higher score for climate regulations (R10) today compared to the past.
Lessons learnt from the Schlei assessment are that number, relevance and importance of indicators underlying an ES class differ very much. In some cases, indicator scores are opposing, and after averaging on ES class level, the contradictions result in no changes over time or between water bodies. As consequence, the reality is sometimes hidden. For some indicators, like beach closures, an assessment between two time periods is problematic since the legal framework (
Important questions were, whether an assessment on water body level makes sense and to what extent information from one water body can be transferred to another one, to save time and resources.
Selected comparative ecosystem service assessments in the Schlei Estuary:
Since water bodies are a subdivision of WFD coastal water types and share many properties, a lack of data in a water body largely could be compensated with data from another neighboring water body. Therefore, the spatial transfer of basic data and information is possible and reasonable, however, in detail water bodies within on type differ significantly.
The comparative assessment of two time periods, the 1880s compared to today and the early 1960s compared to today reveals significant differences and developments between the periods. The 1880s were supposed to reflect the reference state (high ecological state) and the early 1960s the good ecological status of the Schlei according the WFD. Especially the changes between the early 1960s and today give an indication on how the ES provision of an ecosystem could look like in future after the full and successful implementation of the WFD.
With respect to the Schlei, it is questionable whether in the early 1960s a good ecological status still existed. Already in the 1950s, the use of fertilizers in agriculture increased by almost 50%, from about 37 kg P (P2O5) kg ha-1 up to 60 kg P (P2O5) kg ha-1 (
Shallow systems with a long coastline, a relatively large drainage basin and limited water exchange are sensitive to eutrophication. In northern Germany, several systems have to be considered as naturally eutrophic. As consequence, the “good status” according to the WFD is a eutrophic status. This is the case for the Schlei, as well. This limits the possibility for an improved human use of the Schlei, but does not violate our concept.
The quality of an ES assessment depends on availability and quality of data and information. To link the ES assessment to the WFD allows the usage of data that is collected in all EU countries within the WFD monitoring (e.g., Secchi depth, pH, salinity, oxygen, nutrients). Much recent and historic data has been prepared for the first steps in implementing the WFD, for example the development of a typology or the definition of reference conditions. This improves the conditions for an ES assessment. Further, several countries used ecological models for defining historic states and this spatial information on water body level is available, as well. Despite that, data availability and reliability is still a problem for several indicators and this problem increases when addressing the 1960s and especially the 1880s. Usually 35–50% of the information used in our assessment is based on assumptions or expert knowledge (
Type and quality of information sources used in the ES assessment in the Schlei Estuary. The assessment includes the indicators of 22 ES classes. For indicators of 9 ES classes no data could be found.
Already for centuries, the industrialized and urban Warnow Estuary was intensively used and modified by humans. As consequence, comprehensive monitoring datasets, detailed statistics, a large amount of planning documents and experts with specific knowledge exist. The availability and quality of data as basis for an ES assessment is much better compared to a natural system, like the Schlei Estuary. This is true for historic data, as well. Compared to the Schlei Estuary, much information about the state and situation around 1880–1900 is available. It means that from an information availability perspective, industrialized and urban systems are most suitable for an ES assessment. Despite that, serious information gaps for this historic period exist. Even in these systems, historic ES assessments and comparisons are based on a weak information basis and can hardly be regarded as reliable.
While natural systems are hardly affected by political and economic changes, this is different in urban and industrialized systems. After the Second World War until 1990, the Warnow Estuary belonged to the socialistic German Democratic Republic (GDR). During that time, a very specific development took place. Rostock was the only international harbor of the GDR and the most important location for shipbuilding industries. As consequence of the industrialisation, the population increased from about 70,000 after the Second World War to above 250,000 in 1990. During that time, the estuary was heavily modified. For example, the shipping channels were deepened and the coastline became largely artificial. As consequence, pollution increased and water quality declined.
One question is whether the political changes and associated developments are visible in our ES assessment? Some regulating ES classes, like mass stabilization, nursery grounds, fixing processes and chemical conditions, or the provisioning ES classes plant and animal outputs reflect these changes (
ES classes are based on one to several indicators. The indicators not only differ with respect to their quality as descriptor of an ES class, but also with respect to the data reliability. A question is, whether changes are possibly hidden by poor data quality. Another question is, whether inverse changes of indicators, describing one ES class, may cause no or only weak changes of ES classes and hide changes. A possible solution to these potential problems could be a weighting of indicators and/or ES classes, taking into account data quality.
Data based ES assessment for the entire Warnow Estuary provision. Shown are changes between 1960 (WFD good ecological status) and today. The scores for ES classes are calculated with two methods: by averaging and weighted averaging. The latter takes into account data reliability. Reliability scores indicate very high (1, weighting factor 2) to low (4, weighting factor 0.5) data quality. Positive ES class scores indicate an increase in ES provision today (
Only four ES classes show differences in scores, indicated by exclamation marks, between both methods: animal outputs, nursery grounds, pest control and climate regulation. Only with respect to ES class animal outputs the difference is above one unit and has significant impact on the result. Altogether, the advantage of taking data reliability into account has only negligible effects on the overall assessment and therefore is not beneficial in this study.
The ES classes in
Instead of carrying out an ES assessment for describing and visualizing historic changes, it can be applied to assess possible future states of a system using a tailor-made, expert based system. Usually industrial and urban estuaries, like the Warnow Estuary, are defined as heavily modified water bodies. According to the WFD, this allows defining less strict ecological quality objectives. In the Warnow Estuary, for example, only a moderate ecological state needs to be achieved. However, nearly two decades after WFD adoption its objectives usually have not been reached. This is true for the Warnow Estuary, but also for most coastal waters in Germany and all over Europe (
The question is whether an ES assessment can provide these incentives by visualizing the human benefits of a healthy coastal water. For this purpose, we developed a future scenario for the year 2040 for the Warnow Estuary and asked altogether 19 experts to compare it to the present state (
Ecosystem service (ES) classes used in expert-based assessment for the Warnow Estuary. The authors, 11 scientists and 5 experts (persons working at water authorities on the WFD implementation) scored the changes between today and the future scenario “Warnow 2040.” The assessment is separated into two water bodies, the northern industrial (see
The Warnow and Schlei Estuaries show that the importance of provisioning services is relatively low (
Even a strong increase in the provision of provisioning services because of a good ecological status alone would hardly give a convincing justification for improving environmental quality and the required investments. Cultural services and changes in their provision have a most direct impact and relevance to a broad public, especially in urban systems. The ES assessments of cultural services show a slight increase in the industrial, northern and a strong increase in the urban, southern water body (
A systematic difference in the perception of changes that would result from an implementation of the scenario “Warnow 2040” between the separately assessed groups of authors, scientists (working at scientific institutions) and experts (working at authorities) is not visible. However, the perception between individual persons differs strongly, even within the three groups. For example, while persons E2 and E5 do not expect an overall increase of ES for the urban water body, persons S1, S2, and S7 expect a strong increase. Some scientists seem to be more positive about the scenario, while some persons working at authorities seem more skeptical.
With respect to single ES classes there are many strong differences and contradicting scores among the assessors. For example, with respect to changes in cultural service provision in the urban water body, namely experiential use and existence and bequest, the majority of persons expects increases, but single persons perceive the change differently and expect strong decreases. These differences point out ES where different perceptions, world-views, understandings or knowledge exist.
On average, the knowledge between the group of scientists and the authority experts did not differ. Based on a self-assessment and with respect to geographical knowledge it was considered good to very good and about the ecological status of the Warnow Estuary medium to good. The authority experts indicated a good to very good knowledge about the WFD and its implementation while the scientists indicated only a medium to good knowledge. Some experts stated only little or moderate knowledge about one of the topics. Either, they only moved recently to the area, or were not professionally dealing with the ecological status of the Warnow Estuary. The group of scientists (including the authors) showed strong differences when asked about their knowledge about the WFD, ranging from little to excellent. However, comparing experts with excellent knowledge (A1, A2, and S3) with the one that indicated little/moderate knowledge (S4, S5, S6, S10), does not show systematic difference in the assessment results (
The feedback discussions with the involved experts addressed benefits and weaknesses of the approach. The experts saw the need to further improve the definition of several indicators and suggested a narrower scoring system between -3 and 3. They were concerned that the indicators only partly reflect the biological elements of the WFD, about the subjectivity of the individual scoring, limitations of the provided background information or simplifications in the scenario. Further that the scenario goes much beyond the focus of the WFD and the subjective influence resulting from visualization and presentation of the scenario. Especially in the Warnow Estuary, experts were concerned that the potential for improvements in the ecological status is limited and spatially restricted to smaller areas or that improvements resulting from the WFD water quality improvements require measures in the river basin. It means that costs, possible disadvantages and benefits are separated spatially. One expert saw the risk that in other cases a good ecological status may not increase the overall ES provision. Another concern was the possible conflict between harbor development and water quality improvement.
The vast majority of experts saw the potential benefits of an application within the WFD in the possibility to better involve stakeholders in planning of measures and in transferring aims and benefits of the WFD and its implementation to a broader public, and thus increase its acceptance.
Previous studies show that an absolute assessment of ES is problematic. This is especially true for monetary assessments, for example ES classes addressing coastal aesthetics. Different approaches for valuation need to be used for different ES and make results difficult to compare. As consequence,
Our approach to utilize major elements of the WFD for an ES assessment turned out to be beneficial, because we used a politically and societally accepted normative system as framework, were able to adapt a generally accepted spatial seascape subdivision and were able to utilize large amounts of data that were raised and compiled for the WFD implementation. Another advantage was that it enabled us to involve a defined group of experienced and interested experts in the ES assessment. Therefore, the practical benefit of the WFD approach for an ES assessment in coastal waters goes beyond the conceptual links and synergies compiled by
An advantage of the data-based comparative assessment between two periods in time is a reduced subjectivity. However, the data basis for the reference (high ecological) state according to the WFD (years around 1880) or the good ecological state (around 1960) is partly weak. Comparisons to the present state are hardly reliable in detail. Comparative historic assessments show general trends and give an idea, how intensified human uses and eutrophication have changed the provision of a broad spectrum of ES in water bodies. Further, these comparisons give an insight in potential benefits (usually increased ES provisions) that may be provided when coastal waters are in a good ecological state again, as result of a full WFD implementation.
The two assessed coastal water systems, the rural Schlei and the urban/industrialized Warnow Estuary can, with respect to structure, problems and challenges for WFD implementation be regarded as representative for a large spectrum of coastal water systems, at least at the southern Baltic Sea. Therefore, major aspects of the approach can be transferred to and applied in other coastal waters. In case of urbanized/industrial estuaries, for example, to Kiel, Lübeck, Flensburg, or Szczecin.
Another aspect is that commonly used ES classes and indicators, like CICES 5.1 (
According to
The spatial size of a system has strong effects on its accessibility, on the visible details and the overall result. Size-limitations result from availability and spatial resolution of data. What we learnt from our study is that historic assessments need larger spatial units. They should be carried out on estuary level, because of data availability. For expert based assessments, smaller spatial units are preferable, like water bodies that sub-divide an estuary. Smaller, more homogeneous spatial units are more tangible and concrete for the involved external experts and allow a more reliable scoring. Further, smaller spatial units allow more concrete definitions and visualizations of future scenarios.
Relatively low values for provisional ES are not specific for German waters or only observed in industrialized coastal water systems, but are common for most coastal waters world-wide (
ES assessments do not provide crisp and reliable data and results. They rather indicate ongoing changes and allow visualizing changes and possible benefits for humans, resulting from an improved ecological status. Especially cultural services have a direct relevance for the local population and changes are directly perceivable. As indicated by our involved experts, ES assessments may play a role in WFD public relations and information.
The WFD integrates economics into water management and water policy decision-making (
The WFD, Article 14, specifies that European Union member states shall encourage the active involvement of all interested parties in the implementation of the WFD (
Planning within the WFD usually includes current and foreseen scenario assessments, target setting as well as development and implementation of alternative programmes of measures (
Our ES assessment approaches turned out to be suitable for the historic and future scenario applications. It utilizes major elements of the WFD for the ES assessment, like the spatial seascape subdivision, allows for a direct comparison of ES classes with different units, is spatially expandable and transferable and enables a relatively fast assessment. The two assessed coastal water systems, the rural Schlei and the urban/industrialized Warnow Estuary share many similarities with other southern Baltic Sea estuaries (historic development, morphogenesis, hydrological conditions) and to a certain degree, the results can be regarded as representative for other Baltic coastal water systems.
In the European WFD implementation, ES assessments can serve as a complementary approach to support the economic analysis of measure programs as well as planning and implementation processes. However, an ES assessment not only supports the WFD implementation, but the WFD provides a frame for larger scale ES assessments in seascapes, increases the acceptance of the ES approach and the readiness of stakeholders to get involved.
Data-based comparative ES assessments of different time periods allow visualizing changes that happened in coastal waters during the last decades and consequences for human uses. They can also visualize potential benefits and costs resulting from urban development plans (Warnow 2040). Expert-based ES assessments allow for comparing sets of measures or scenarios and can serve as a tool in public participation and stakeholder involvement processes. Independently of the approach, ES assessment results hardly can be regarded as reliable information. Strengths are that they facilitate communication processes, broaden the view and the knowledge and support social learning processes. Our study in practice proves that the conceptual considerations by
All experts involved in the assessment were informed about the intention to publish the assessment results and orally agreed to it. They had the possibility to review and comment the results.
GS, the project leader, developed the manuscript concept, took care of the data analyses and did the manuscript writing. MI provided the assessment tool and graphical visualizations. PP carried out the ES assessment in the Schlei and ER in the Warnow. ER and JS prepared the scenario “Warnow 2040,” largely moderated the meetings with stakeholders and took minutes.
The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.
We like to thank Amina Baccar Chaabane, Dr. Ricarda Börner, Dr. Clemens Engelke, Dr. Stefanie Felsing, Dr. René Friedland, Mirco Haseler, Rahel Hauk, Dr. Svenja Karstens, Xaver Lange, Simon Paysen, Lukas Ritzenhofen, Laura Schulz, Dr. Andreas Starmans, Miriam von Thenen and Mario von Weber for supporting the evaluation or providing data and information.
The Supplementary Material for this article can be found online at:
Data sources and definition of data quality.