Search Results (3)

Coastal lagoons are increasingly affected by altered salinity regimes due to river diversion and hydrological regulation, with major impacts on ecosystem structure and functioning. The Venice Lagoon is a paradigmatic case, where centuries of river diversion have reduced freshwater inputs, causing widespread marinization and the decline of brackish habitats such as reedbeds (Phragmites australis). Within the LIFE Lagoon Refresh project, controlled freshwater inputs from the Sile River (300–1000 L s⁻¹ since 2020) were reintroduced into the Ca’ Zane Valley to restore salinity gradients. Vegetation responses were assessed by comparing pre-diversion (2018) and post-diversion (2024) conditions across 28 salt marsh platforms (9.82 ha) using field surveys, UAV imagery, satellite data and GIS analysis. Both freshwater inflow, which reduced salinity from values > 30 psu to mean values of 0.22 and 5.6 psu near the canal inlet and within a few hundred meters, respectively, and reed transplants triggered rapid changes in plant communities. Hypersaline species such as Salicornia procumbens subsp. veneta, Limonium narbonense, and Sarcocornia fruticosa declined, while brackish species such as Galatella tripolium and Phragmites australis expanded, reaching up to 75% cover in areas with salinity < 10 psu. These findings demonstrate that controlled freshwater inflows and transplants of suitable species can represent an effective nature-based solution for the sustainable restoration of coastal lagoons, habitat diversity, ecosystem functionality, biodiversity conservation, and long-term resilience to environmental change. Full article

The stress gradient hypothesis (SGH) states that plant-plant interactions shift from competition to facilitation in increasing stress conditions. In salt marshes, edaphic properties can weaken the application of the SGH by amplifying the intensity of flooding and controlling plant zonation. We identified facilitative and competitive interactions along flooding gradients and tested the role of edaphic properties in exacerbating stress and shaping plant-plant interactions. Morphological traits of two target halophytes (Limonium narbonense and Sarcocornia fruticosa), flooding intensity, soil texture and soil organic C were recorded. The relative plant fitness index was assessed for the two species based on the relative growth in plurispecific rather than monospecific plant communities. Plant fitness increased with increasing stress supporting the SGH. L. narbonense showed larger fitness in plurispecific stands whereas S. fruticosa performed better in conspecific stands. Significant intra- or interspecific interactions were observed along the stress gradient defined by the combination of flooding and clay content in soil. When considering the limited soil organic C as stressor, soil properties were more important than flooding in defining plant-plant interactions. We highlight the need for future improvements of the SGH approach by including edaphic stressors in the model and their possible interactions with the main abiotic drivers of zonation. Full article

Limonium is a genus represented in the Iberian Peninsula by numerous halophytic species that are affected in nature by salinity, and often by prolonged drought episodes. Responses to water deficit have been studied in four Mediterranean Limonium species, previously investigated regarding salt tolerance mechanisms. The levels of biochemical markers, associated with specific responses—photosynthetic pigments, mono- and divalent ions, osmolytes, antioxidant compounds and enzymes—were determined in the control and water-stressed plants, and correlated with their relative degree of stress-induced growth inhibition. All the tested Limonium taxa are relatively resistant to drought on the basis of both the constitutive presence of high leaf ion levels that contribute to osmotic adjustment, and the stress-induced accumulation of osmolytes and increased activity of antioxidant enzymes, albeit with different qualitative and quantitative induction patterns. Limonium santapolense activated the strongest responses and clearly differed from Limonium virgatum, Limonium girardianum, and Limonium narbonense, as indicated by cluster and principal component analysis (PCA) analyses in agreement with its drier natural habitat, and compared to that of the other plants. Somewhat surprisingly, however, L. santapolense was the species most affected by water deficit in growth inhibition terms, which suggests the existence of additional mechanisms of defense operating in the field that cannot be mimicked in greenhouses. Full article