The Wadden Sea is the largest unbroken system of intertidal sand and mud flats in the world. The site covers the Dutch Wadden Sea Conservation Area, the German Wadden Sea National Parks of Lower Saxony and Schleswig-Holstein, and most of the Danish Wadden Sea maritime conservation area. It is a large, temperate, relatively flat coastal wetland environment, formed by the intricate interactions between physical and biological factors that have given rise to a multitude of transitional habitats with tidal channels, sandy shoals, sea-grass meadows, mussel beds, sandbars, mudflats, salt marshes, estuaries, beaches and dunes. The area is home to numerous plant and animal species, including marine mammals such as the harbour seal, grey seal and harbour porpoise. Wadden Sea is one of the last remaining large-scale, intertidal ecosystems where natural processes continue to function largely undisturbed. © UNESCO
2020 Conservation Outlook
Current state and trend of VALUES
Overall PROTECTION and MANAGEMENT
Click the + and - signs to expand or collapse full accounts of information under each topic. You can also view the entire list of information by clicking Expand all on the top left.
Description of values
Depositional coastline of unparalleled scale and diversity
One of the last remaining natural large-scale intertidal ecosystems with natural processes continuing to function largely undisturbed
Key site for migratory birds
Exceptional species richness in a salt marsh
A permanent trilateral coordination group on alien and invasive species was formed by the Wadden Sea Board in 2018, with the remit of finalising a trilateral management and action plan on alien species (MAPAS) and coordinating efforts towards a harmonized trilateral and ongoing specific monitoring program for alien species (CWSS, 2020a).
A legacy of bottom-dredging fishery (the mechanical Dutch cockle fishery in particular) has destroyed biodiversity-rich communities including the disappearance of the intertidal mussel beds in some areas of the site (Ens et al., 2004). Studies on the impact of the cockle fishery in particular concluded that the area of mudflats containing sufficient shellfish for feeding knots decreased by fifty-five percent between 1996 and 2005. During the same period, knot numbers decreased by forty-two percent (Kraan et al., 2009) and was also attributed to the loss of 15,000 oystercatchers (Ens et al., 2004).
The shrimp fishery, which has been increasing for many years, is also responsible for a large bycatch of young fish, young shrimp and other invertebrates. Also a number of fish species with slow growth (rays and sharks) and reef building animals such as Sabellaria have disappeared in the Wadden Sea, the shrimp fishery most probably being responsible (IUCN Consultation, 2017). Except for the Danish Wadden Sea there is very little management of this fishery. Management is also complicated by the human induced population growth of brown shrimp, thought to have been induced by overfishing of predator species such as cod and whiting (Kloepper et al., 2017).
Fisheries have now been further regulated (IUCN, 2009) and the blue mussel and brown shrimp fisheries are now subject to increased efforts towards sustainability (Kloepper et al., 2017). These include a transition to alternative fishing methods and a new Management Plan for North Sea Brown Shrimp; and alternative seed mussel collection technology being developed (Kloepper et al., 2017) and Denmark has now banned shrimp and mussel fishery entirely.
Access to the harbours and maintenance of navigation channels is subject to an integrated planning system including sediment management, both to maintain the shipping routes and to avoid environmental impacts to the marine and coastal ecosystems. However, it is clear that the deepening of the navigation channels also has an impact on the site, which should be kept as small as possible. Also there is a tendency to modify and/or enlarge harbours, with some impact on the site, which must be reduced as much as possible. On New Year's Day 2019, a cargo ship lost 342 containers and 3,000 tons of cargo overboard, resulting in huge quantities of litter washing up on beaches and into the sea within the site in the Netherlands (and to a lower extend also in Germany), leading a report to recommend measures including those for '(a specific category of) container ships, and if necessary alteration of the two shipping routes north of the Wadden Islands' (Corder, 2019).
Designation as an IMO Particularly Sensitive Sea Area (PSSA) and implementation of a shipping Traffic Management System and emergency contingency plans are state of the art, but shipping will continue to be a significant risk for the foreseeable future (IUCN, 2009).
Due to intensive wind farm development in the North Sea outside the Wadden Sea there is clearly an increase in the risk for shipping accidents which would then have an impact on the site. Industrial plants such as power or chemical plants are close to the site in some areas.
Subsidence as a result of gas extraction in the Dutch part of the Wadden Sea is causing impacts, with a maximum of 42cm subsidence reported in 2015 underneath Ameland island (van Thienen-Visser et al., 2015). However, gas production is adjusted or halted if there are signs that the subsidence capacity will be exceeded (Kloepper et al., 2017). Considering that due to sea level rise the Wadden Sea may face a sediment deficit in the longer term, the sediment which compensates now the subsidence will later be missing in the site.
Recommendations in the Committee Decision 38COM 8B.13 (Request No. 5) to prepare an implementation plan to enhance the conservation and management in the Danish part has been undertaken. The Danish National Park was evaluated in 2016-2017 and a new plan was approved in 2019 (Nationalpark Vadehavet, 2019).
Recommendations in the Committee Decision 38COM 8B.13 (Request No. 6) to implement a single integrated management plan (SIMP) and to strengthen the implementation of coordinated management have been undertaken. The current timeline resulted in a formal decision on the development of the SIMP in spring 2018 (Trilateral Governmental Conference), which provided the necessary institutional support and funding to start developing the SIMP in mid-2018 (Leeuwarden Declaration, 2018). The development of the SIMP is currently in progress.
Recommendations in the Committee Decision 38COM 8B.13 (Request No. 7) to extend the monitoring of impacts of fisheries and to ensure protection from detrimental impacts have been started in the form of a trilateral Framework of Sustainable Fisheries (adopted in 2014) listing several important principles. There is also a basic fisheries monitoring in place (using VMS, logbooks and a black box approach). However, the actual implementation on the Committee Decision still lacks a clear timetable and /or a roadmap for implementation, as well as more clearly defined targets, methods and dependencies between detrimental effects, species, biotopes and fishing methods.
|№||Organization||Brief description of Active Projects||Website|
|1||Common Wadden Sea Secretariat||Wadden Sea flyway initiative||
|2||Common Wadden Sea Secretariat||Prowad Link - Protect and Prosper||
|3||Numerous research and conservation projects||Numerous research and conservation projects are undertaken in the site by the three State Parties, too numerous to list here.|
Becherer, J., Hofstede, J., Gräwe, U., Purkiani, K., Schulz, E., & Burchard, H. (2018). The Wadden Sea in transition-consequences of sea level rise. Ocean Dynamics, 68(1), pp.131-151.
Benninghoff, M., & Winter, C. (2019). Recent morphologic evolution of the German Wadden Sea. Scientific Reports, 9(1), 9293.
BirdLIfe (2009). The Wadden Sea: A vision for the conservation of a Natural Heritage. http://www.birdlife.org/europe/pdfs/Waddenvision.pdf
Blew, J., Günther, K., Hälterlein, B., Kleefstra, R., Laursen, K. and Scheiffarth, G. (2016). Trends of Migratory and Wintering Waterbirds in the Wadden Sea 1987/1988 - 2013/2014. Wadden Sea Ecosystem No. 37. Common Wadden Sea Secretariat, Joint Monitoring Group of Migratory Birds in the Wadden Sea, Wilhelmshaven, Germany.
Brasseur S., Carius F., Diederichs B., Galatius A., Jeß A., Körber P., Schop J., Siebert U., Teilmann J., Bie Thøstesen C. & Klöpper S. (2020). EG-Seals grey seal surveys in the Wadden Sea and Helgoland in 2019-2020. Common Wadden Sea Secretariat, Wilhelmshaven, Germany.
Burbridge, P.R. (2000). The Nomination of the Wadden Sea Conservation Area as a World Heritage Site: A Feasibility Study For the Trilateral Wadden Sea Cooperation/ Common Wadden Sea Secretariat. 29 pp.
CWSS (2010). Wadden Sea Plan 2010. Eleventh Trilateral Governmental Conference on the Protection of the Wadden Sea. Common Wadden Sea Secretariat, Wilhelmshaven, Germany.
CWSS (2012). The Wadden Sea, Germany and Netherlands (N1314) - Extension Denmark and Germany. Nomination file for Danish extension to the WHC.
CWSS (2013). Aerial surveys of Harbour Seals in the Wadden Sea in 2013. Available at: https://www.waddensea-worldheritage.org/resources/2013-grey…
CWSS (2014). Ministerial Council Declaration. 12th Trilateral Governmental Conference on the Protection of the Wadden Sea, Trilateral Wadden Sea Governmental Council Meeting, Tønder, 5 February 2014. Available at: https://www.waddensea-worldheritage.org/resources/2014-tønd…
CWSS (2016). Report on the State of Conservation of the World Heritage property “The Wadden Sea (N1314)”. Wilhelmshaven, Germany.
CWSS (2020a). Alien Species. [online] Available at: https://www.waddensea-worldheritage.org/alien-species (Accessed 17 September 2020).
CWSS (2020b). Shaping a Sustainable Tomorrow - Wadden Sea Strategy on Education for Sustainable Development and World Heritage Interpretation. [online] Available at: https://www.waddensea-worldheritage.org/resources/education… (Accessed 18 September 2020).
CWSS (2018). 2018- 2022 Conservation Management Plan Wadden Sea Seal Population. [online] Available at: https://www.waddensea-worldheritage.org/resources/seal-mana… Accessed 18 September 2020).
Claessens, M., De Meester, S., Van Landuyt, L., De Clerck, K., Janssen, C.R. (2011). Occurrence and distribution of microplastics in marine sediments along the Belgian coast. Marine Pollution Bulletin. 62: 2199-2204.
Corder, M. (2020). Report highlights risks for container ships in Wadden Sea. Associated Press. [online] Available at: https://www.businessinsider.com/report-highlights-risks-for… (Accessed 18 September 2020).
Dekiff, JH., Remy, D., Klasmeier, J., Fries, E. (2014). Occurrence and spatial distribution of microplastics in sediments from Norderney. Environmental Pollution, 186, pp.248-256.
Dittmann T., Becker P.H., Bakker J., Bignert A., Nyberg E., Pereira M.G., Pijanowska U., Shore R., Stienen E., Toft G.O. & Marencic H. (2012). Large-scale spatial pollution patterns around the North Sea indicated by costal bird eggs within an EcoQO programme. Environ. Sci. Pollut. Res. 19: 4060-4072.
Ens, B. J., Smaal, A. C., & De Vlas, J. (2004). The effects of shellfish fishery on the ecosystems of the Dutch Wadden Sea and Oosterschelde: final report on the second phase of the scientific evaluation of the Dutch shellfish fishery policy (EVA II) (No. 1011). Alterra.
Ens, B.J., Blew, J., van Roomen, M.W.J., & van Turnhout, C A.M. (2009). Exploring contrasting trends of migratory waterbirds in the Wadden Sea. Wadden Sea Ecosystem no. 27. Common Wadden Sea Secretariat.
Europarc Consulting (2012). Facts and Figures of the Wadden Sea Region. Part I of the Baseline Study for the Strategy for Sustainable Tourism in the Wadden Sea. Prowad Protect and Prosper: Sustainable Tourism in the Wadden Sea, co-financed by Interreg IVE North Sea Region Programme and EU European Regional Development Fund.
Fries, E., Dekiff, J.H., Willmeyer, J., Nuelle, M.-T., Ebert, M., Remy, D. (2013). Identification of polymer types and additives in marine microplastic particles using pyrolysis-GC/MS and scanning electron microscopy. Environmental Science: Processes and Impacts, 15, pp.1949-1956.
Galatius, A., Brackmann, J., Brasseur, S., Diederichs, B., Jeß, A., Klöpper, S., Körber, P., Schop, J., Siebert, U., Teilmann, J., Thøstesen, B. and Schmidt, B. (2020) Trilateral surveys of Harbour Seals in the Wadden Sea and Helgoland in 2020. Common Wadden Sea Secretariat, Wilhelmshaven, Germany.
Gittenberger, A. (2016). Alien species of the Wadden Sea database. Issued by Office of risk assessment and research, the Netherlands Food and Consumer Product Safety Authority.
Heron S.F., Day J.C., Zijlstra R., Engels B., Weber A., Marencic H and Busch J.A. (2020). Workshop report: Climate Risk Assessment for Wadden Sea World Heritage property. Application of the Climate Vulnerability Index – Outstanding Universal Value (OUV) Vulnerability. 68 pages. Common Wadden Sea Secretariat, Wilhelmshaven, Germany.
Hötker, H., Schrader, S., Schwemmer, P., Oberdiek, N., and Blew, J. (2010). Status, threats and conservation of birds in the German Wadden Sea. Technical Report NABU (available online at: http://www.unep-aewa.org/news/news_elements/2010/NABU_Statu…).
ICES (2003). Ecological Quality Objectives. ICES 2003ACE Report
ICES (2004). Ecological Quality Objectives. ICES Advice 2004, ACFM/ACE Report
IUCN (2009). World Heritage Nomination – IUCN Technical Evaluation, The Wadden Sea (Germany/The Netherlands). In: IUCN World Heritage Evaluations 2009, IUCN Evaluations of nominations of natural and mixed properties to the World Heritage List. WHC/09/33.COM/INF.8B2. [online] Gland, Switzerland: IUCN, pp.16-28. Available at: <https://whc.unesco.org/document/152335> [Accessed November 2020].
IUCN (2014). World Heritage Extension Nomination – IUCN Technical Evaluation, Wadden Sea (Denmark, Germany, The Netherlands). In: IUCN World Heritage Evaluations 2014, IUCN Evaluations of nominations of natural and mixed properties to the World Heritage List. WHC/14/38.COM/INF.8B2. [online] Gland, Switzerland: IUCN, pp.43-51. Available at: https://whc.unesco.org/en/list/1314/documents/ [Accessed 24 September 2020].
Jager, Zwanette (2015). Conservation Management of Fish Populations in the Wadden Sea. Hamburg, 8-9 January 2015 - Workshop Report. Common Wadden Sea Secretariat. 26 pp.
Kloepper, S., Baptist, M. J., Bostelmann, A., Busch, J.A., Buschbaum, C., Gutow, L., Janssen, G., Jensen, K., Jørgensen, H.P., de Jong, F., Lüerßen, G., Schwarzer, K., Strempel, R. & Thieltges, D. (2017). Wadden Sea Quality Status Report 2017. [online] Common Wadden Sea Secretariat. Available at: https://qsr.waddensea-worldheritage.org/ (Accessed 17 September 2020).
Koffijberg, K. and van Roomen, M. (2019). Wadden Sea Flyway Initiative - Linking the Wadden Sea World Heritage Site with tropical wetlands and the Arctic Tundra. Available at: https://www.waddensea-worldheritage.org/sites/default/files…
Koffijberg, K., Laursen, K., Hälterlein, B., Reichert, G., Frikke, J. and Soldaat, L. (2015). Trends of Breeding Birds in the Wadden Sea 1991 - 2013. Wadden Sea Ecosystem No. 35. Common Wadden Sea Secretariat, Joint Monitoring Group of Breeding Birds in the Wadden Sea, Wilhelmshaven, Germany.
Kraan, C., Van Gils, J. A., Spaans, B., Dekinga, A., Bijleveld, A. I., Van Roomen, M., ... & Piersma, T. (2009). Landscape‐scale experiment demonstrates that Wadden Sea intertidal flats are used to capacity by molluscivore migrant shorebirds. Journal of Animal Ecology, 78(6), 1259-1268.
Laursen, K., Blew, J., Eskildsen, K., Günther, K., Hälterlein, B., Kleefstra, R., Lüerssen, G., Potel, P., and Schrader, S. (2010). Migratory Waterbirds in the Wadden Sea 1987- 2008. Wadden Sea Ecosystem No.30. Common Wadden Sea Secretariat, Joint Monitoring Group of Migratory Birds in the Wadden Sea, Wilhelmshaven, Germany (available online at: http://www.waddensea-secretariat.org/sites/default/files/do…).
Leeuwarden Declaration. (2018). Ministerial Council Meeting: Leeuwarden Declaration. [online] 13th Trilateral Governmental Conference on the Protection of the Wadden Sea Leeuwarden, 18 May 2018. Available at: https://www.waddensea-worldheritage.org/sites/default/files… (Accessed 18 September 2020).
MELUR (Ministerium für Energiewende, Landwirtschaft, Umwelt und ländliche Räume des Landes Schleswig-Holstein). 2015. Strategie für das Wattenmeer 2100. Online: http://www.schleswig-holstein.de/DE/Fachinhalte/N/nationalp….
Madsen, J. (1998). Experimental Refuges for Migratory Waterfowl in Danish Wetlands: II. Tests of Hunting Disturbance Effects. Journal of Applied Ecology, 35, 398-417.
Madsen, J. and Fox, A.D. (1995). Impacts of Hunting Disturbance on Waterbirds - a Review. Wildlife Biology, vol 1, no. 4, pp. 193-206.
Marencic, H. (2009). The Wadden Sea - Introduction. Thematic Report No. 1. In: Marencic, H. & Vlas, J. de (Eds), 2009. Quality Status Report 2009. Wadden Sea Ecosystem No. 25. Common Wadden Sea Secretariat, Trilateral Monitoring and Assessment Group, Wilhelmshaven, Germany.
Miljøstyrelsen (2017). Fiskeriterritoriet og reservater. Vadehavet. [online, map]. Available at: mst.dk/media/129515/vadehavet-kortbilag-1.pdf
Nationalpark Vadehavet (2019). Plan for Nationalpark Vadehavet 2019 – 2014. Available at: https://nationalparkvadehavet.dk/media/246375/npv-plan-2019…
Nolte, S. (2013). Grazing as a nature-management tool on mainland salt marshes - Results of the Noord-Friesland grazing experiment. Univ Groningen. (paper given on Wadden Sea Day 29 August, 2013).
Nomination (2008). The Wadden Sea German/The Netherlands). Volume 1 (164 pp.) Volume 2 (24 annexes).
OSPAR (2007). Background document on the EcoQO on mercury and organohalogens in seabird eggs. OSPAR Commission, Assessment and Monitoring series, No. 331.
OSPAR (2009). EcoQO Handbook - Handbook for the application of Ecological Quality Objectives in the North Sea. Second Edition - 2009. OSPAR Biodiversity Series Publication 307/2009. OSPAR Commission London, 65 pp.
PROWAD (2014). Sustainable Tourism in the Wadden Sea World Heritage Destination. PROWAD – Protect and Prosper: Sustainable Tourism in the Wadden Sea’, co-financed by the Interreg IVB North Sea Region Programme (www.prowad.org).
Reneerskens, J. (2020). Climate change effects on Wadden Sea birds along the East-Atlantic flyway. [online] Leeuwarden:Wadden Academy. Available at: https://www.waddenacademie.nl/organisatie/publicatie-lijst/… (Accessed 18 September 2020).
Rösner, H-U. (2010). The Guiding Principle for the Wadden Sea: Advantages of a dynamic approach in a changing world. Wadden Sea Ecosystem 26: 23-28.
Thienen-Visser, V., Breunese, J. N., & Muntendam-Bos, A. G. (2015). Subsidence due to gas production in the Wadden Sea: How to ensure no harm will be done to nature. In 49th US Rock Mechanics/Geomechanics Symposium. American Rock Mechanics Association.
Thorup, O. and Koffijberg, K. (2016). Breeding success in the Wadden Sea 2009-2012 A review. Ecosystem No. 36. Common Wadden Sea Secretariat, Wilhelmshaven, Germany.
Unger, B., Herr, H., Benke, H., Böhmert, M., Burkhardt-Holm, P., Dähne, M., Hillmann, M., Wolff-Schmidt, K., Wohlsein, P., Siebert, U. (2017). Marine debris in harbour porpoises and seals from German waters. Marine Environmental Research, 130, pp.77-84.
Vermeersen, B. L., Slangen, A. B., Gerkema, T., Baart, F., Cohen, K. M., Dangendorf, S., ... & Jevrejeva, S. (2018). Sea-level change in the Dutch Wadden Sea. Netherlands Journal of Geosciences, 97(3), pp.79-127
WWF (2012). Energy Production and Nature Conservation in the Wadden Sea Region and the Wadden Sea: Future Perspectives. Presentation at Wadden Sea Day, 30 August 2012. Available at: http://www.wwf.de/fileadmin/fm-wwf/Publikationen-PDF/120830…
WWF (2013). A Bright Outlook - Feasibility Study on Climate-friendly Tourism in the Wadden Sea Region. WWF Germany, Husum. Available at: http://www.wwf.de/fileadmin/fm-wwf/Publikationen-PDF/Feasib…
WWF (2014). Klimaschutz und -anpassung im Wattenmeer [online]. WWF Deutschland, updated 22 February 2016. Available at: http://www.wwf.de/watt/klima
Wadden Sea Board. (2019). Agenda Item: 5.1 World Heritage; Development of the Single Integrated Management Plan. [online] Common Wadden Sea Secretariat. Available at: https://www.waddensea-worldheritage.org/system/files/wsb-29… (Accessed 17 September 2020).
Wanner, A. (2013). Grazing effects on vegetation, breeding birds, silica and sediments in salt marshes: Results of the BASSIA-project. Univ. Hamburg. (paper given on Wadden Sea Day 29 August, 2013).
Wolff, W.J., Bakker, J.P., Laursen, K. and Reise, K. (2010). The Wadden Sea Quality Status Report—Synthesis Report 2010. Wadden Sea Ecosystem No. 29. Common Wadden Sea Secretariat, Wilhelmshaven, Germany. Pp. 25-74.
World Heritage Committee (2009). Decision: 33 COM 8B.4 The Wadden Sea Statement of Outstanding Universal Value (Germany, Netherlands). In: Decisions Adopted by the World Heritage Committee at its 33rd Session (Seville, 2014). [online] Paris, France: UNESCO World Heritage Centre, pp.183-186. Available at: <http://whc.unesco.org/en/decisions/1946> [Accessed November 2020].
World Heritage Committee. (2014). Decision: 38 COM 8B.13. Wadden Sea (Denmark, Germany, The Netherlands). In: Report of decisions of the 38th session of the World Heritage Committee. [online] Paris, France: UNESCO World Heritage Centre. Available at: https://whc.unesco.org/en/decisions/6098 [Accessed 24 September 2020].
van Beusekom, J., Carstensen, J., Dolch, T., Grage, A., Hofmeister, R., Kerimoglu, O., ... & Rönn, L. (2019). Wadden Sea Eutrophication: long-term trends and regional differences. Frontiers in Marine Science, 6, 370.
van Roomen, M., Laursen, K., van Turnhout, C., van Winden, E., Blewc, J., Eskildsen, K., Günther, K., Hälterlein, B., Kleefstra, R., Potel, P., Schrader, S., Luerssen, G., and Ens, B. J. (2012). Signals from the Wadden sea: Population declines dominate among waterbirds depending on intertidal mudflats. Ocean & Coastal Management 68: 79-88.
van Roomen, M., Nagy, S., Citegetse, G. and Schekkerman, H. (2018) (eds). East Atlantic Flyway Assessment 2017: the status of coastal waterbird populations and their sites. Wadden Sea Flyway Initiative p/a CWSS, Wilhelmshaven, Germany, Wetlands International, Wageningen, The Netherlands, BirdLife International, Cambridge, United Kingdom. Available at: https://www.waddenseaworldheritage.org/sites/default/files/…