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Wetlands, as defined by the Convention on Wetlands of International Importance (Ramsar, 197166), include a wide variety of inland habitats and other marine areas no deeper than six meters at low tide.
Wetlands include a wide variety of inland habitats such as marshes, wet grasslands and peatlands, floodplains, rivers and lakes, and coastal areas such as saltmarshes, mangroves, intertidal mudflats and seagrass beds, and coral reefs and other marine areas no deeper than six meters at low tide, as well as human-made wetlands such as dams, reservoirs, rice paddies and wastewater treatment ponds and lagoons (Ramsar Convention Secretariat, 2016). 66 The most comprehensive definition of wetlands is from the convention on wetlands, an intergovernmental treaty ratified by 171 parties (but not the EU) in 1971 that provides the framework for national action and international cooperation for the conservation and wise use of wetlands and their resources. In 1995, the commission adopted a communication to the European parliament and the council on the wise use and conservation of wetlands, which recognised the important functions they perform for the protection of water resources and provided the first cross-walk between Ramsar and Corine land cover typologies. 149 Wetlands are the living space for many (protected) species as well as migratory birds and are crucial in their role of providing habitats and water-related ecosystem services. Erosion control, sediment transport, water filtration and regulation are a few of the many valuable services delivered by this ecosystem. In recent times, the role of healthy (vegetated) wetlands in tackling climate change (mitigation, adaptation, resilience) has been emphasized, namely their capacity to capture and store carbon and so reduce atmospheric greenhouse gases, and provide better resilience to hazards such as flooding, storm surges and coastal inundation (Ramsar Convention on Wetlands, 2018).
The degraded condition of wetlands in Europe is influenced by several factors related mainly to a) the lack of a comprehensive European policy framework targeting these ecosystems in a consistent manner, b) the misdefinition and mis-representation of wetlands in different classification systems, and c) the low socio-cultural valuation of these ecosystems, facilitating changes in land uses. Specifically:
a) In Europe, the over-arching policy framework for wetlands that addresses wetland ecosystems holistically dates from 1995 and has not been updated since. Instead, wetland ecosystem management is partially addressed by different legislative instruments (EU Biodiversity Strategy and Nature Directives, Climate Strategy, Water Framework Directive, Flood Directive, Marine Strategy Framework Directive). Though these have some synergetic effects on wetland management and conservation, they nevertheless lack objectives explicitly targeting the whole wetland ecosystem integrity. Instead, they address only parts of this ecosystem for certain purposes: habitats and species of interest; pollution control; flood risks; and/or carbon sequestration.
b) Though the Ramsar Convention is the global framework defining wetland ecosystems, in Europe the term ‘wetlands’ tends to reflect the differences in landscapes and uses across the continent, often linked to cultural traditions. The existing systems for classifying these habitat units (namely EUNIS, CLC, MAES, LULUCF classifications; Table 3.4.1) have so given way in Europe to a diversity of approaches to their definition over time, hindering a uniform delimitation of wetlands and ultimately leading to a fragmented assessment and management of wetlands.
c) At a socio-cultural and economic level, European wetlands have been historically considered as low productive land that should be subject to dryland forms of cultivation. This profit-driven approach to wetland resources (for example peat extraction, or dryland agriculture) has overlooked the biological, hydro-ecological and socio-economic values and status of wetlands, which as a consequence has degraded this ecosystem, altering its functioning and other undervalued services it provides to people.
Conditions and pressures
The MAES ecosystem types focus the classification of wetlands on the “inland wetlands” category, so coastal wetlands are classified as marine inlets and transitional waters (Box 3.4.1 and Table 3.4.2). This categorization restricts the in-depth assessment of wetlands per se within MAES to inland wetland habitats (i.e. peatlands and marshes) only. However, areas that are currently treated as separate ecosystem types by MAES, are ecologically linked by their own water flows. Thus, water is released from upland peatlands into rivers, and then moves through marshes and lakes, before rivers issue into coastal wetlands such as estuaries with their saltmarshes and other coastal habitats. In addition to the in-depth assessment performed for MAES inland wetlands, this chapter also addresses coastal wetlands to the best possible extent and driven by the available knowledge and data (section 1.1.4). 151 Furthermore, as a future-looking recommendation to assess wetlands more holistically and as a full ecosystem, section 1.1.5 sets the way forward for the use of an adapted wetlands’ nomenclature in Europe, hereafter “extended wetland”, based on the Ramsar definition and classification of wetlands, taking stock of the approach set by the Horizon 2020 SWOS initiative67 . This extended definition of European wetlands according to their hydro-ecological dimension follows the Ramsar classification of wetland habitats that ensures the identification of transitional ecosystem types hydro-ecologically belonging to wetlands (Table 3.4.2). The extended delimitation of wetland ecosystems and the comprehensive delineation of wetland habitats are introduced in section 1.1.5 together with the information currently available on their condition. Box 3.4.1 refers to the different definitions of wetland habitats considered in this wetland assessment.
Historically, European wetlands have suffered great declines, continued degradation and habitat loss that are still taking place due to different persisting drivers. The results of the MAES wetland assessment overwhelmingly confirms that, though efforts are ongoing to better conserve and more effectively manage and restore wetlands in Europe, the ecological character of wetland habitats is still dire (see also separate assessments by Ramsar Convention, 2018 and Davidson et al., 2019). Evidence extracted from the MAES assessment shows that compared to all terrestrial, freshwater and marine ecosystems, wetlands represent the ecosystem in the worst condition in Europe. To add to the specific pressures affecting wetlands, the climate change crisis including changes in precipitation and rising temperatures are contributing to worsening wetlands condition and affecting their function and its capacity to provide key ecosystem services, namely carbon sequestration and flood regulation, among others. The degraded condition of wetlands in Europe is influenced by several factors related mainly to the lack of a European policy that considers wetland ecosystems, wetlands definition and their change in use and sociocultural values in a comprehensive way. This patchy treatment of wetland habitats and their underlying biodiversity by legislative and regulatory tools is reflected by a heterogeneous condition reported for different wetland habitats. Whereas rivers and lakes, fully covered by the WFD but also by other ones (Nitrates, Bathing Water, Urban Waste Water treatment Directives) show a better condition status or somehow certain signs of improvement (Chapter 3.6), habitats such as intertidal flats, open mires, rice fields, riparian forests and wet grasslands, which, beside the Habitats Directive, are not specific targets of European policies, show a much worse status that is also deteriorating in time
This wetland ecosystem assessment reveals that the condition of extended wetlands in Europe over the last two decades is poor or degraded. Inland wetland ecosystems and their habitats continue to suffer from multiple pressures that are stable or even increasing over time except for nutrient enrichment that shows a significant decrease during the last decades linked to effective regulation. Despite significant wetland restoration efforts in Europe over the last decades, which have already proved, at local scale, to effectively decrease wetland extent loss, the assessment demonstrates that tangible improvements in the condition of wetlands and the reestablishment of their functions are far from being met. This critical situation dominating wetlands requires transformative changes at all levels enabling the implementation of long-term mechanisms and governance models at multiple scales that are implemented based on ecosystem-based conservation and adaptive monitoring programmes that respect the hydroecological boundaries of this ecosystem.