Percorrer por autor "Gizzi, Francesca"
A mostrar 1 - 2 de 2
Resultados por página
Opções de ordenação
- Before and after a disease outbreak: tracking a keystone species recovery from a mass mortality eventPublication . Gizzi, Francesca; Jiménez, Jesús; Schäfer, Susane; Castro, Nuno; Costa, Sónia; Lourenço, Sílvia; José, Ricardo; Canning-Clode, João; Monteiro, JoãoMass mortality events involving marine taxa are increasing worldwide. The long-spined sea urchin Diadema africanum is considered a keystone herbivore species in the northeastern Atlantic due to its control over the abundance and distribution of algae. After a first registered mass mortality in 2009, another event off the coasts of Madeira archipelago affected this ecologically important species in summer 2018. This study documented the 2018 D. africanum mass mortality event, and the progress of its populations on the southern coast of Madeira island. A citizen science survey was designed targeting marine stakeholders to understand the extent and intensity of the event around the archipelago. Underwater surveys on population density prior, during and after the mass mortality, permitted an evaluation of the severity and magnitude of the event as well as urchin population recovery. A preliminary assessment of causative agents of the mortality was performed. The event was reported in the principal islands of the archipelago reducing the populations up to 90%. However, a fast recovery was registered during the following months, suggesting that the reproductive success was not compromised. Microbiological analyses in symptomatic and asymptomatic individuals, during and after the event, was not conclusive. Nevertheless, the bacteria Aeromonas salmonicida, or the gram-negative bacteria, or the interaction of different types of bacteria may be responsible for the disease outbreak. Further studies are needed to assess the role of pathogens in sea urchin mass mortalities and the compound effects that sea urchins have in local habitats and ecological functioning of coastal marine ecosystems.
- A new signal of tropicalization in the Northeast Atlantic: the spread of the spotfin burrfish Chilomycterus reticulatus in Madeira Archipelago and its invasion riskPublication . Castro, Nuno; Schäfer, Susanne; Parretti, Paola; Monteiro, João Gama; Gizzi, Francesca; Chebaane, Sahar; Almada, Emanuel; Henriques, Filipe; Freitas, Mafalda; Vasco-Rodrigues, Nuno; Silva, Rodrigo; Radeta, Marko; Freitas, Rúben; Canning-Clode, JoãoCurrent trends in the global climate facilitate the displacement of numerous marine species from their native distribution ranges to higher latitudes when facing warming conditions. In this work, we analyzed occurrences of a circumtropical reef fish, the spotfin burrfish, Chilomycterus reticulatus (Linnaeus, 1958), in the Madeira Archipelago (NE Atlantic) between 1898 and 2021. In addition to available data sources, we performed an online survey to assess the distribution and presence of this species in the Madeira Archipelago, along with other relevant information, such as size class and year of the first sighting. In total, 28 valid participants responded to the online survey, georeferencing 119 C. reticulatus sightings and confirming its presence in all archipelago islands. The invasiveness of the species was screened using the Aquatic Species Invasiveness Screening Kit. Five assessments rated the fish as being of medium risk of establishing a local population and becoming invasive. Current temperature trends might have facilitated multiple sightings of this thermophilic species in the Madeira Archipelago. The present study indicates an increase in C. reticulatus sightings in the region. This underlines the need for updated comprehensive information on species diversity and distribution to support informed management and decisions. The spread of yet another thermophilic species in Madeiran waters provides further evidence of an ongoing tropicalization, emphasizing the need for monitoring programs and the potential of citizen science in complementing such programs.