Modelling Habitat Distribution of Mediterranean Coastal Wetlands: The Ebro Delta as Case Study

Benito, Xavier; Trobajo, Rosa; Ibáñez, Carles

doi:10.1007/s13157-014-0541-2

Cited by 21 publications

(13 citation statements)

References 40 publications

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“…In tidal wetlands, differences in flooding frequency along elevational gradients often induce sharp gradients in oxygen availability and redox conditions (Davy et al, 2011;, with potentially strong influence on OM decomposition and carbon cycling. However, the effect of redox conditions on OM breakdown is determined by the chemical quality of the decomposing material: decomposition of aged or recalcitrant OM can indeed be slower and incomplete in the absence of oxygen, whereas the breakdown of fresh and labile OM can be largely unaffected by oxygen availability (Benner et al, 1984;Kristensen et al, 1995). Thus, also decomposition rate and stabilization of labile, hydrolyzable OM, as assessed in the present study, is not necessarily affected by redox conditions.…”

Section: Relative-sea-level Effects On Decomposition Processesmentioning

confidence: 59%

Global-change effects on early-stage decomposition processes in tidal wetlands – implications from a global survey using standardized litter

et al. 2018

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Abstract. Tidal wetlands, such as tidal marshes and mangroves, are hotspots for carbon sequestration. The preservation of organic matter (OM) is a critical process by which tidal wetlands exert influence over the global carbon cycle and at the same time gain elevation to keep pace with sea-level rise (SLR). The present study assessed the effects of temperature and relative sea level on the decomposition rate and stabilization of OM in tidal wetlands worldwide, utilizing commercially available standardized litter. While effects on decomposition rate per se were minor, we show strong negative effects of temperature and relative sea level on stabilization, as based on the fraction of labile, rapidly hydrolyzable OM that becomes stabilized during deployment. Across study sites, OM stabilization was 29 % lower in low, more frequently flooded vs. high, less frequently flooded zones. Stabilization declined by ∼ 75 % over the studied temperature gradient from 10.9 to 28.5 ∘C. Additionally, data from the Plum Island long-term ecological research site in Massachusetts, USA, show a pronounced reduction in OM stabilization by > 70 % in response to simulated coastal eutrophication, confirming the potentially high sensitivity of OM stabilization to global change. We therefore provide evidence that rising temperature, accelerated SLR, and coastal eutrophication may decrease the future capacity of tidal wetlands to sequester carbon by affecting the initial transformations of recent OM inputs to soil OM.

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Section: Relative-sea-level Effects On Decomposition Processesmentioning

confidence: 59%

Global-change effects on early-stage decomposition processes in tidal wetlands – implications from a global survey using standardized litter

et al. 2018

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“…Apart from additional urban uses and sand beaches, several wetland types still occupy part of the Ebro Delta. Some of them are salt marshes located at the coast, whereas others are freshwater to brackish wetlands, with different plant communities, distributed along the Delta but separated from the sea [29]. Further than these two main wetland types, freshwater wetlands were also abundant in the Ebro Delta, though many of them were transformed to rice fields.…”

Section: Introductionmentioning

confidence: 99%

Carbon metabolic rates and GHG emissions in different wetland types of the Ebro Delta

et al. 2020

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Deltaic wetlands are highly productive ecosystems, which characteristically can act as Csinks. However, they are among the most threatened ecosystems, being very vulnerable to global change, and require special attention towards its conservation. Knowing their climate change mitigating potential, conservation measures should also be oriented with a climatic approach, to strengthen their regulatory services. In this work we studied the carbon biogeochemistry and the specific relevance of certain microbial guilds on carbon metabolisms of the three main types of deltaic wetlands located in the Ebro Delta, northeastern Spain, as well as how they deal with human pressures and climate change effects. We estimated the metabolic rates of the main carbon-related metabolisms (primary production and respiration) and the resulting carbon and global warming potential balances in sites with a different salinity range and trophic status. With the results obtained, we tried to define the influence of possible changes in salinity and trophic level linked to the main impacts currently threatening deltaic wetlands, on the C-metabolisms and GHG emissions, for a better understanding of the mitigating capacity and their possible enhancement when applying specific management actions. Metabolic rates showed a pattern highly influenced by the salinity range and nutrients inputs. Freshwater and brackish wetlands, with higher nutrient inputs from agricultural runoff, showed higher C-capture capacity (around 220-250 g C m-2 y-1), but also higher rates of degradative metabolisms (aerobic respiration and CH 4 emissions). Contrastingly, the rates of C-related metabolisms and C-retention of Salicornia-type coastal salt marshes were lower (42 g C m-2 y-1). The study of the microbial metacommunity composition by the16S RNA gene sequencing revealed a significant higher presence of methanogens in the salt marsh, and also higher metabolic potential, where there was significantly more organic matter content in sediment. Salinity inhibition, however, explained the lower respiration rates, both aerobic and anaerobic, and prevented higher rates of methanogenesis despite the major presence of methanogens. Conservation measures for these wetlands would require, overall, maintaining the sediment contributions of the river basin intending to overcome the regression of the Delta and its salt marshes in a climate change scenario. Particularly, for reducing degradative metabolisms, and favour C-retention, nutrient inputs should be controlled in freshwater and brackish wetlands in order to reduce eutrophication.

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“…The Ebro Delta (NW Mediterranean) constitutes an example of a highly modified human area, with ca. 65% of previous salt marsh–estuarine ecosystems now being devoted to rice cultivation ( Benito, Trobajo & Ibáñez, 2014 ). Most of the remaining natural surface has been integrated into the Ebro Delta Natural Park, except for a fragment of salt marsh facing Alfacs Bay, which is not subjected to local management.…”

Section: Introductionmentioning

confidence: 99%

Effects of enhanced hydrological connectivity on Mediterranean salt marsh fish assemblages with emphasis on the endangered Spanish toothcarp (Aphanius iberus)

Prado¹,

Alcaraz²,

Jornet³

et al. 2017

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The hydrological connectivity between the salt marsh and the sea was partially restored in a Mediterranean wetland containing isolated ponds resulting from former salt extraction and aquaculture activities. A preliminary assessment provided evidence that ponds farther from the sea hosted very large numbers of the endangered Spanish toothcarp, Aphanius iberus, suggesting that individuals had been trapped and consequently reach unnaturally high densities. In order to achieve both habitat rehabilitation and toothcarp conservation, efforts were made to create a gradient of hydrologically connected areas, including isolated fish reservoirs, semi-isolated, and connected salt marsh-sea areas that could allow migratory movements of fish and provide some protection for A. iberus. The fish community was monitored prior to, and for three years after rehabilitation. Results showed an increase in the number of fish species within semi-isolated areas (Zone A), whereas areas adjacent to the sea (Zone B) increased the number of marine species and decreased that of estuarine species (ES). Yet overall differences in fish assemblages were much higher between zones than among study years. Generalized linear models (GLMs) evidenced that distance to the sea was the most important variable explaining the local diversity of the fish community after restoration, with occasional influence of other factors such as temperature, and depth. The abundance of A. iberus was consistently higher in semi-isolated areas at greater distances from the sea, but a decline occurred in both zones and in isolated reservoir ponds after restoration efforts, which may be attributable to interannual differences in recruitment success and, to a lesser extent, to dispersal into adjacent habitats. A negative effect of restoration works on fish population cannot be excluded, but the final outcome of the intervention likely needs a longer period.

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Modelling Habitat Distribution of Mediterranean Coastal Wetlands: The Ebro Delta as Case Study

Cited by 21 publications

References 40 publications

Global-change effects on early-stage decomposition processes in tidal wetlands – implications from a global survey using standardized litter

Global-change effects on early-stage decomposition processes in tidal wetlands – implications from a global survey using standardized litter

Carbon metabolic rates and GHG emissions in different wetland types of the Ebro Delta

Effects of enhanced hydrological connectivity on Mediterranean salt marsh fish assemblages with emphasis on the endangered Spanish toothcarp (Aphanius iberus)

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