Examinando por Autor "Chefaoui, Rosa M."

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Seasonal variations of waterbird ecological networks under different saltpans management
(Elsevier, 2021) Chefaoui, Rosa M.
Habitat change has increased the loss of wetlands and impacted highly on coastal biodiversity. Consequently, wetland-dependent species such as waterbirds have experienced a decline in their populations. This study proposes an application of bipartite networks using both the sampled sites and species as nodes to assess seasonal variations in waterbirds composition and habitat specialization in response to the abandonment of saltpans. The sampling was carried out in active and abandoned saltpans of the Ria Formosa (Portugal) over four sampling periods to evaluate the temporal change in waterbird communities. Abundance was twice and species richness 14% higher in active saltpans than in abandoned ones. About 60% of the waterbirds indicated a high specificity towards active saltpans. Saltpans showed a high β-diversity and seasonal dynamic of waterbird community composition. Network dissimilarity across the year was dominated by turnover of the edges rather than species turnover. Dynamics in network structure and composition seemed to be related to bird dispersal, migration phenology, and habitat specialist strategies. Overall, this study highlights the importance of preserving the activity of saltpans as it conditions abundance, richness and dynamics of waterbird populations. Continued efforts are needed to reduce threats to coastal wetlands and restore abandoned saltpans worldwide, since these are key habitats for the conservation of resident and migratory waterbirds.
Temporal variability of sea surface temperature affects marine macrophytes range retractions as well as gradual warming
(2024) Chefaoui, Rosa M.; Martínez, Brezo D.-C.; Viejo, Rosa M.
Record mean sea surface temperatures (SST) during the past decades and marine heatwaves have been identified as responsible for severe impacts on marine ecosystems, but the role of changes in the patterns of temporal variability under global warming has been much less studied. We compare descriptors of two time series of SST, encompassing extirpations (i.e. local extinctions) of six cold-temperate macroalgae species at their trailing range edge. We decompose the effects of gradual warming, extreme events and intrinsic variability (e.g. seasonality). We also relate the main factors determining macroalgae range shifts with their life cycles characteristics and thermal tolerance. We found extirpations of macroalgae were related to stretches of coast where autumn SST underwent warming, increased temperature seasonality, and decreased skewness over time. Regardless of the species, the persisting populations shared a common environmental domain, which was clearly differentiated from those experiencing local extinction. However, macroalgae species responded to temperature components in different ways, showing dissimilar resilience. Consideration of multiple thermal manifestations of climate change is needed to better understand local extinctions of habitat-forming species. Our study provides a framework for the incorporation of unused measures of environmental variability while analyzing the distributions of coastal species.