Main Threats in Mediterranean Coastal Wetlands. The Ebro Delta Case

Abstract

Coastal wetlands are dynamic ecosystems that exist at the interface between land and sea. They represent environments with a great diversity of habitats and communities, high carbon sequestration capacity and a wide range of ecosystem services. In the Mediterranean, the largest coastal wetlands are found in deltaic areas like that of the Ebro River (Spain), which has a coastline length of approximately 50 km, occupying a total area of 325 km2. The Ebro Delta is included in different national and international frameworks for environmental conservation, despite which there are several risks that threaten it. The lack of sedimentary contributions due to the regulation of the Ebro riverbed (irrigation, reservoirs, and hydroelectric power generation) has caused erosion and the retreat of certain sections of its coastline. To this situation of sediment deficit must be added the threat posed by the effects of global change, such as the rise in sea level, the increase in temperature and in the frequency and intensity of storms. This study analyses the particularities of the coastal wetland of the Ebro Delta, identifying the main threats it faces, as well as possible adaptation and mitigation strategies to these changes.

Faunistic and Structural Changes in Shallow Coastal Benthic Communities of the Ebre Delta (NW Mediterranean Sea)

“…The Ebre Delta coastal area is a dynamic ecosystem subject to flooding, erosion, extreme events, and changes in its morphological configuration, which have made this area very vulnerable to the threats of global change [54]. The increase in water temperature is already causing changes in species composition and abundance in the Mediterranean [55], giving an advantage to tropical invasive species over the native ones [56].…”

Analysing Spatiotemporal Variability of Chlorophyll-a Concentration and Water Surface Temperature in Coastal Lagoons of the Ebro Delta (NW Mediterranean Sea, Spain)

“…Situated in the Western Mediterranean within Catalonia, Spain, the Ebro Delta is one of the largest deltas in the north-western region of the Mediterranean Sea (320 km 2 ), and is recognised as Spain's second-most vital wetland, following the Doñana wetland on the Atlantic coast of Andalusia [12]. Its environmental significance is underscored by a wide array of habitats including marshes, coastal lagoons, beaches, and dunes, among others, of high ecological value (Figure 1).…”

“…As can be seen, coastal lagoons are intricate ecosystems where primary production and water temperature interact dynamically. In addition, these complex variable interactions are further influenced by human pressures (e.g., changes in land use and nutrient and organic matter pollution, as well as undesired effluents from agriculture, industry, and aquaculture) and global climate change effects (e.g., sea-level rise, storminess, high water and air temperatures, extreme events) [11][12][13][14]. The previous are threatening the water quality and the trophic status of these rich and valuable ecosystems, which indeed require frequent, long-term, and large-scale monitoring to ensure their preservation.…”

Waterbird Species Are Highly Sensitive to Wetland Traits: Simulation-Based Conservation Strategies for the Birds of the Sicilian Wetlands (Italy)

“…Besides the common threats acting upon wetland ecosystems, climate-induced sea level rises will increase the frequency of saltwater intrusions in coastal wetlands [14]. The increased evaporation caused by climate warming, combined with saltwater intrusions, could alter these ecosystems and decrease their species richness [15].…”