Percorrer por autor "Bourweiss, Mohammed"
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- Long range gene flow beyond predictions from oceanographic transport in a tropical marine foundation speciesPublication . Tavares, Ana I; Assis, Jorge; Larkin, Patrick D.; Creed, Joel C.; Magalhães, Karine; Horta, Paulo; Engelen, Aschwin; Cardoso, Noelo; Barbosa, Castro; Pontes, Samuel; Regalla, Aissa; Almada, Carmen; Ferreira, Rogério; Abdoul, Ba Mamadou; Ebaye, Sidina; Bourweiss, Mohammed; dos Santos, Carmen Van-Dúnem; Patrício, Ana R.; Teodosio, Maria; Santos, Rui; Pearson, Gareth; Serrao, Ester AThe transport of passively dispersed organisms across tropical margins remains poorly understood. Hypotheses of oceanographic transportation potential lack testing with large scale empirical data. To address this gap, we used the seagrass species, Halodule wrightii, which is unique in spanning the entire tropical Atlantic. We tested the hypothesis that genetic differentiation estimated across its large-scale biogeographic range can be predicted by simulated oceanographic transport. The alternative hypothesis posits that dispersal is independent of ocean currents, such as transport by grazers. We compared empirical genetic estimates and modelled predictions of dispersal along the distribution of H. wrightii. We genotyped eight microsatellite loci on 19 populations distributed across Atlantic Africa, Gulf of Mexico, Caribbean, Brazil and developed a biophysical model with high-resolution ocean currents. Genetic data revealed low gene flow and highest differentiation between (1) the Gulf of Mexico and two other regions: (2) Caribbean-Brazil and (3) Atlantic Africa. These two were more genetically similar despite separation by an ocean. The biophysical model indicated low or no probability of passive dispersal among populations and did not match the empirical genetic data. The results support the alternative hypothesis of a role for active dispersal vectors like grazers.
- Season and seagrass: drivers of fish assemblage structure in the Banc d'Arguin, MauritaniaPublication . Compain, Philippe; Mallmann, Antonia; Sidina, Ebaye; Bourweiss, Mohammed; Ba, Mamadou Abdoul; Talla, Ismaila Samba; Niang, Alioune; Erzini, Karim; Serrao, Ester A.The Banc d’Arguin is the most ecologically significant coastal wetland of West Africa, a UNESCO Marine World Heritage area with one of the most extensive seagrass areas on Earth, used by many marine species as breeding and/or feeding habitat. However, little is known about the subtidal biodiversity supported by these extensive seagrass meadows. This study aimed to assess the influence of subtidal seagrass vegetation on fish assemblages, using beach seines to compare vegetated and unvegetated habitat. Effects of season and site were also assessed. We sampled fish communities predominantly composed of juveniles (98.7 %). Specifically, we analyzed differences in abundance, species richness, diversity, evenness, and assemblage structure across these factors. Season was the most influential driver of fish assemblage structure, even more than habitat, as expected in a nursery area where fish reproduce seasonally. Notably, four species - Atherina boyeri, Eucinostomus melanopterus, Mugil capurrii, and Chelon dumerili - accounted for 53.7 % and 49.2 % of the variation in assemblages across habitat and season, respectively. Moreover, four times as many species were found exclusively in seagrass habitats compared to unvegetated areas, underscoring the critical role of seagrass meadows in the Banc d’Arguin in supporting species that depend on such shallow sheltered habitats, enhancing regional biodiversity, and contributing to the sustainability of fisheries.