Browsing by Issue Date, starting with "2025-07-17"
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- Mapping saltmarsh vertical distribution communities in southern Portugal using high spatiotemporal resolution satellite imageryPublication . Martins, Márcio; Parreira, Filipe; Ito, Paula; Santos, Rui; Gotha, Simon von sachsen-Coburg Und; Barrena de los Santos, CarmenSaltmarshes, transitional coastal habitats between terrestrial and marine ecosystems, offer crucial ecological benefits, including coastal protection, biodiversity enhancement, water purification and carbon sequestration. However, saltmarsh areas are shrinking, primarily due to human activities. Traditional monitoring approaches for saltmarsh coverage are often costly and restricted in spatial scope, prompting a shift towards remote sensing techniques. While remote sensing has proven effective for studies that cover large spatial areas, its application for smaller areas remains challenging. In this study, we trained classification models to identify saltmarsh vegetation communities in southern Portugal. We utilized high-resolution (3-metre) and high-frequency (near-daily) imagery to optimize image selection according to tidal conditions at the time of capture and developed an elevation proxy for the intertidal zone. Our model achieved an overall accuracy of 67%, estimating a total of 4,572 ha of saltmarsh in southern Portugal, 85% located in the Ria Formosa lagoon. The middle saltmarsh zone, dominated by Atriplex portulacoides, Salicornia perennis and Salicornia fruticosa, covered the largest area. The approach presented here holds promise for further refinement, enabling automated, high-resolution monitoring of saltmarsh communities, which is essential for conservation and management initiatives.
- Intercropping with gramineous plants in nutrient solutions as a tool to optimize the use of iron in brassica oleraceaPublication . Saavedra, Teresa; Pestana, Maribela; Costa, João; Gonçalves, Paula; Fangueiro, David; Silva, José Paulo da; Correia, Pedro JoséThis study aimed to evaluate the impact of intercropping Brassica oleracea. with three perennial grasses (Poa pratensis L., Lolium perenne L., and Festuca rubra L.) under varying levels of iron (Fe) availability (Fe0, Fe1 and Fe5) in nutrient solutions. The research focused on biomass accumulation, photosynthetic efficiency, root development, nutrient uptake, and oxidative stress response. In the absence of Fe, Brassica sp. exhibited chlorosis, reduced biomass, and increased ferric chelate reductase (FCR) enzyme activity as an adaptive response. Brassica plants intercropped with Poa sp. maintained higher chlorophyll (Chl) levels and photosystem II efficiency (Fv/Fm values), mitigating Fe deficiency effects. Catalase activity and polyphenol production varied with intercropping species, indicating differential stress response mechanisms. Intercropping improved Zn, Mn, and P accumulation, with Poa sp. facilitating greater Zn and Mn uptake. Intercropping Brassica sp. with specific grass species offers potential agronomic benefits by improving Fe use efficiency, mitigating stress, and enhancing nutrient uptake. Future research should focus on optimizing intercropping combinations for sustainable agricultural practices.