Examinando por Autor "Des, Marisela"

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Drivers of the fine-scale distribution of a canopy-forming seaweed at the southern edge of its range
(Inter-Research Science Publisher, 2024-01-25) Viejo, Rosa M.; Des, Marisela; Gutiérrez, David
There is growing emphasis on using fine-grained scales to identify the drivers of species’ geographic range edges, which is essential for predicting the response of species to climate change. This is of particular relevance at the ‘rear-edge’ of species distributions, where higher spatial resolution may also help in the detection of potential refugia for conservation. The southern edge of the range of several canopy-forming algae falls in the NW Iberian Peninsula, where large embayments (rias), influenced by strong upwelling events, may act as contemporary climatic refugia for these key coastal organisms. We investigated the factors driving the fine-scale occupancy patterns of the seaweed Fucus serratus, employing a combination of transplant experiments and a fine-grain species distribution model (SDM). Our study revealed that habitat suitability for this species is restricted to particular sites within rias. Transplant experiments showed that germling survival was significantly reduced outside the distribution range. Grazing may limit the species distribution towards the outer sections of rias, where we found the highest densities of grazing gastropods, but not towards the innermost sections. Both winter salinity and autumn seawater temperature were important predictors in the SDM. Our model projections indicate the potential future extirpation of F. serratus in rias with an increase of 1.5°C in maximum autumn temperature, below the predicted average warming of 2ºC for this upwelling area by the end of the century under the SSP5-8.5 scenario. The results highlight the importance of the autumn season for the performance of this cold-temperate seaweed at the southern edge of its range.
The impact of climate change on the geographical distribution of habitat-forming macroalgae in the Rías Baixas
(Elsevier, 2020-10) Des, Marisela; Martínez, Brezo; de Castro, Maite; Viejo, Rosa M.; Sousa, Magda Catarina; Gómez-Gesteira, Moncho
In the current scenario of climate change characterized by a generalized warming, many species are facing local extinctions in areas with conditions near their thermal tolerance threshold. At present, the southern limit of the geographical distribution of several habitat-forming algae of cold-temperate affinities is located in the Northwest Iberian Peninsula, and the Rías Baixas may be acting as contemporary refugia at the range edge. Therefore, it is necessary to analyze future changes induced by ocean warming in this area that may induce changes in macroalgae populations. The Delft3D-Flow model forced with climatic data was used to calculate July–August sea surface temperature (SST) for the present (1999–2018) and for the far future (2080–2099). Mean daily SST was used to develop and calibrate a mechanistic geographical distribution model based on the thermal survival threshold of two intertidal habitat-forming macroalgae, namely Himanthalia elongata (L.) S.F.Gray and Bifurcaria bifurcata R. Ross. Results show that H. elongata will become extinct in the Rías Baixas by the end of the century, while B. bifurcata will persist and may occupy potential free space left by the decline in H. elongata.