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- Population density, reproduction cycle and nutritional value of Sphaerechinus granularis (Echinodermata: Echinoidea) in an oceanic insular ecosystemPublication . Lourenço, Sílvia; José, Ricardo; Neves, Pedro A.; Góis, André; Cordeiro, Nereida; Andrade, Carlos; Ribeiro, CláudiaSea urchins play an important role in island coastal ecosystems as keystone species and as potential resources for harvesting and aquaculture. In Southern Europe, the most valuable and harvested species is the European purple sea urchin Paracentrotus lividus, but there is a growing interest to explore other edible species like the blunt sea urchin Sphaerechinus granularis. The echinoderms biodiversity of Madeira archipelago was previously described, but their local habitat, population densities and size distribution, important to establish their harvest and aquaculture potential, are poorly known. The present study aimed to evaluate S. granularis population in the oligotrophic and narrow insular shelf of Madeira archipelago, mainly regarding its habitat, densities, reproduction season and roe marketable characteristics. Sphaerechinus granularis was found in low densities (0.01 ind./m(2)) from shallow to deep reefs (5-30 m). The highest densities occurred in shallow waters and breakwaters in association to encrusting algae, turf and erect brown macroalgae. Here, the low primary productivity ecosystem influenced the long reproductive season of the local population. This population showed a relatively high gonadosomatic index (maximum GI of 8), high gonad weight (5.00-12.19 g) with high proportion of bright yellow and orange gonads (37.5-60%) between February and November. Additionally, the high level of total carotenoids, the high PUFA (particularly EPA) content, and the ratio n-6/n-3 close to one support the high nutritional value of S. granularis roe. The trend of incremental GI between September and November and the increasing content of PUFA in autumn suggests this could be the preferential harvesting season. This information is key to evaluate a sustainable exploitation of this living marine resource.
- “Pink round stones”—rhodolith beds: an overlooked habitat in Madeira ArchipelagoPublication . Neves, Pedro A.; Silva, João; Peña, Viviana; Ribeiro, CláudiaDespite its worldwide distribution in sedimentary infralittoral and circalittoral bottoms, rhodolith beds have been the subject of fewer studies than other nearshore communities, like kelp forests and coral reefs. This is also the case in Madeira archipelago (Eastern Atlantic), where until recently our knowledge on rhodolith beds was limited to a few references to its occurrence and species composition. In the course of an ongoing habitat-mapping project developed in Madeira, observations revealed that rhodolith beds are more common and extensive than previously supposed. The habitat maps for these beds in Madeira archipelago here presented are the first ever produced for the region. They reveal a total of 46 rhodolith beds at eleven different locations spread across three islands (Madeira, Desertas and Porto Santo), with areas ranging from 776 to 101,081 m(2) and at depths between 12 and 35 m. Author's observations, as well as the results suggest that more rhodolith beds are likely to exist in the archipelago, particularly at greater depths and unexplored locations. The application of molecular systematic tools for the identification of rhodolith-forming species revealed the occurrence of four species belonging to the genera Lithothamnion and Phymatolithon. This latter genus is represented by a single species which is commonly found in rhodolith beds of the archipelago. Genetically, our results show similarities both with the rhodolith communities from the Canary islands and the Algarve (south of Portugal) and highlight the singularities of the archipelago's marine flora. The new array of data here presented is deemed essential for an effective management and conservation of these important and sensitive habitats.
- Filling gaps in the Webbnesia marine diversity: the madeiran sponge faunaPublication . Santín, A.; Wirtz, Peter; Neves, Pedro António Nobre Soares Pinto das; Ribeiro, CláudiaDespite few pioneering works in the late XIX and early XX century, the poriferan fauna of Madeira has remained mostly unexplored until today, Madeira being one of the least studied eastern Atlantic archipelagos in terms of its sponge diversity. After a thorough analysis of both new material collected by SCUBA diving as well as a literature research, 140 sponge species are known to occur in the Madeira archipelago. From the 56 species identified by both collected material and pictures, approximately 60% (34 species) are new records for the Archipelago. These 34 new records were found associated with littoral rocky substrates and, to a lesser extent, caves, rhodolith beds and wrecks, within a depth range of 10-35 m depth. Our records also contain several Mediterranean species that have not been previously recorded in the North Atlantic, several North-east Atlantic species whose presence in Madeira marks their southernmost limit of occurrence, as well as elements from the subtropical West African fauna. Amongst the new additions to its sponge fauna there are the first records of Homomscleromorpha, with at least three Oscarella species noted, as well as a new species of Hemimycale (Demospongiae, Poecilosclerida). Yet, this is still an underestimation of Madeira's real sponge diversity.
- Positive species interactions structure rhodolith bed communities at a global scalePublication . Bulleri, Fabio; Schubert, Nadine; Hall‐Spencer, Jason M.; Basso, Daniela; Burdett, Heidi L.; Francini‐Filho, Ronaldo B.; Grall, Jacques; Horta, Paulo A.; Kamenos, Nicholas A.; Martin, Sophie; Nannini, Matteo; Neves, Pedro António Nobre Soares Pinto das; Olivé, Irene; Peña, Viviana; Ragazzola, Federica; Ribeiro, Cláudia; Rinde, Eli; Sissini, Marina; Tuya, Fernando; Silva, JoãoRhodolith beds are diverse and globally distributed habitats. Nonetheless, the role of rhodoliths in structuring the associated species community through a hierarchy of positive interactions is yet to be recognised. In this review, we provide evidence that rhodoliths can function as foundation species of multi-level facilitation cascades and, hence, are fundamental for the persistence of hierarchically structured communities within coastal oceans. Rhodoliths generate facilitation cascades by buffering physical stress, reducing consumer pressure and enhancing resource availability. Due to large variations in their shape, size and density, a single rhodolith bed can support multiple taxonomically distant and architecturally distinct habitat-forming species, such as primary producers, sponges or bivalves, thus encompassing a broad range of functional traits and providing a wealth of secondary microhabitat and food resources. In addition, rhodoliths are often mobile, and thus can redistribute associated species, potentially expanding the distribution of species with short-distance dispersal abilities. Key knowledge gaps we have identified include: the experimental assessment of the role of rhodoliths as basal facilitators; the length and temporal stability of facilitation cascades; variations in species interactions within cascades across environmental gradients; and the role of rhodolith beds as climate refugia. Addressing these research priorities will allow the development of evidence-based policy decisions and elevate rhodolith beds within marine conservation strategies.