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Projeto de investigação
Feeding ecology of declining seahorse populations of Ria Formosa lagoon
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Autores
Publicações
Mapping saltmarsh vertical distribution communities in southern Portugal using high spatiotemporal resolution satellite imagery
Publication . Martins, Márcio; Parreira, Filipe; Ito, Paula; Santos, Rui; Gotha, Simon von sachsen-Coburg Und; Barrena de los Santos, Carmen
Saltmarshes, 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.
Predation success of declining long-snouted seahorse (Hippocampus guttulatus) population under habitat shifts
Publication . Parreira, Filipe; Palma, Jorge; Santos, Rui; Martínez-Crego, Begoña
Seahorse populations are facing significant declines worldwide, often associated to illegal trade and habitat loss or fragmentation. Emergent habitat shifts towards invasive seaweeds, facilitated by global warming, can also be at play, having still unknown effects on seahorse ecology. Particularly, indirect impacts on seahorse populations via altered predation success remains largely unexplored. Here, we conducted mesocosm experiments to investigate differences in the prey capture success of the long-snouted seahorse (Hippocampus guttulatus) among native habitats (i.e. seagrass meadows and unvegetated sediments) and non-native Caulerpa prolifera meadows when offered different preys (amphipods and shrimps), at low or high prey availability, and under low or high habitat complexity. Great plasticity of H. guttulatus to all habitats was revealed, as habitat type did not significantly affect the capture success. Instead, capture success depends on prey identity and availability regardless of the habitat type, as well as on habitat complexity. Seahorse capture success was higher under high prey availability, as well as when predating on amphipods that were offered together with shrimps. High habitat complexity of both vegetated habitats enhanced by double the capture success, whereas an opposite effect of similar magnitude was found for more complex unvegetated habitats. This indicates that vegetation complexity, regardless their native or invasive nature, reduces prey awareness to predator, whereas small structures in unvegetated habitats provide refuge for preys but not seahorse camouflage. We found no evidence that shifts from native habitats to invasive C. prolifera negatively impact H. guttulatus capture success, but further research on other aspects of its feeding ecology is still necessary.
Unidades organizacionais
Descrição
Palavras-chave
, Natural sciences ,Natural sciences/Biological sciences
Contribuidores
Financiadores
Entidade financiadora
Fundação para a Ciência e a Tecnologia, I.P.
Fundação para a Ciência e a Tecnologia, I.P.
Fundação para a Ciência e a Tecnologia, I.P.
Programa de financiamento
OE
Número da atribuição
2022.11198.BD