Saltmarshes: Ecology, Opportunities, and Challenges
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Saltmarshes: Ecology, Opportunities, and Challenges Olga M. C. C. Ameixa and Ana I. Sousa CESAM – Centre for Environmental and Marine Studies, Department of Biology, University of Aveiro, Campus Universitário de Santiago, Aveiro, Portugal
Saltmarsh ecosystems are essential to coastal food webs providing nursery areas, not only for many fish and crustaceans of recreational and economic importance but also for birds. Despite the relevance and distribution of saltmarshes worldwide, these ecosystems have been facing many threats most of these associated with current global changes such as sea level rise.
Introduction Definitions Saltmarshes are wetlands which mostly occur in intertidal areas, in transitional areas of marine and terrestrial environments, connecting saline to freshwater ecosystems, and are periodically flooded by salt water or brackish water. These areas are usually covered by typical herbs, grasses, or low shrubs, characterized by the ability to tolerate a wide range of salinities and different periodic flooding periods (Adam 1993). Saltmarshes are very dynamic ecosystems, determined by feedback processes between sediment deposition and vegetation growth as well as the balance between erosion and vertical accretion. Saltmarshes occur worldwide, except Antarctica, particularly from middle to high latitudes, and are usually restricted to comparatively sheltered locations. These ecosystems can be found associated with estuaries, barrier islands, spits, embayments, and open shores exposed to low wave energy, as well as fringing coastal lagoons.
Saltmarshes are wetlands located at the transition areas between marine and terrestrial environments, connecting saline to freshwater ecosystems. They mostly occur in intertidal areas, being periodically flooded by salt water or brackish water and exposed to low wave energy. These areas are usually vegetated by typical vascular plants (herbs, grasses, or low shrubs) – halophytes – which can tolerate a wide range of salinities and different periodic flooding periods (Adam 1993). Even though the elevation range for their limit of occurrence is not strict, they usually occupy the upper intertidal area, with an upper limit of occurrence being approximately the elevation of the highest astronomical tide while the lower limit being hardly below mean high water neap tide level. Saltmarshes conservation and biodiversity maintenance at the European level is assured under the EU Habitats Directive (Directive 92/ 43/CEE), wherein European conservation objectives have been elaborated. Different habitat types
© Springer Nature Switzerland AG 2020 W. Leal Filho et al. (eds.), Life Below Water, Encyclopedia of the UN Sustainable Development Goals, https://doi.org/10.1007/978-3-319-71064-8_79-1
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are established in the scope of Habitats Directive, namely, the 1310 (Salicornia and other annuals colonizing mud and sand), the 1320 (Spartina swards), the 1330 (Atlantic salt meadows), the 1420 (Mediterranean and thermo-Atlantic halophilous scrubs), and the habitat 1140 (mudflats and san
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