5 resultados para estratos

em Acceda, el repositorio institucional de la Universidad de Las Palmas de Gran Canaria. España


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[EN] Meiofaunal assemblages from intertidal and shallow subtidal seabeds were studied at two sites (one dominated by volcanic sands and the other by organogenic sands) at Tenerife (Canary Islands, NE Atlantic Ocean) throughout an entire year (May 2000?April 2001). Specifically, we aimed (i) to test for differences in diversity, structure, and stability between intertidal and subtidal meiofaunal assemblages, and (ii) to determine if differences in the meiofaunal assemblage structure may be explained by environmental factors (granulometric composition, availability of organic matter, and carbonate content in sediments). A total of 103,763 meiofaunal individuals were collected, including 203 species from 19 taxonomic groups (Acari, Amphipoda, Cnidaria, Copepoda, Echinodermata, Gastrotricha, Isopoda, Insecta, Kinorrhyncha, Misidacea, Nematoda, Nemertini, Oligochaeta, Ostracoda, Polychaeta, Priapulida, Sipuncula, Tanaidacea, and Turbellaria). Nematodes were the most abundant taxonomic group. Species diversity was higher in the subtidal than in the intertidal zone at both sites, as a result of the larger dominance of a few species in the intertidal zone. The meiofaunal assemblage structure was different between tidal levels at both sites, the intertidal presenting greater temporal variability (multivariate dispersion) in the meiofaunal assemblage structure than the subtidal. Sediment grain size, here quantified by the different granulometric fractions, explained the variability in meiofaunal assemblage structure to a greater extent than the percentage of carbonates, a variable linked to sediment origin. This study revealed differences in diversity, assemblage structure, and variability between intertidal and subtidal meiofauna.

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Máster en Gestión Sostenible de Recursos Pesqueros

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Este trabajo ha sido realizado en el marco de los proyectos PROMECA (CTM2008-04057/MAR) y Campaña Oceanográfica PROMECA-2010 (CTM2009-06993-E/MAR)

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[EN] We examined whether the abundance and size of the starfish Marthasterias glacialis (Lamk.) exhibit a depth-dependent partitioning on subtidal reefs. We tested the hypothesis that differences in food availability can result in habitat partitioning along a depth gradient. The abundance and size of M. glacialis was registered at 4 depth strata: 0-4 m, 4-8 m, 8-12 m, and >12 m; we also recorded the number of food items that they were preying on. The abundance and size of M. glacialis decreased with depth. Mussels (Mytilus galloprivincialis) were the most preyed food item across all depth strata, followed by gastropods, sea urchins and barnacles; M. glacialis also consumed a significantly larger amount of mussels in feeding experiments compared with sea urchins and gastropods. The abundance of M. galloprivincialis beds decreased with depth. The clear link between the decrease in abundance and size of M. glacialis with depth and the decay of the most consumed prey (mussels) suggest that food availability may play an important role in the vertical distribution of this starfish, though wave-associated turbulence in the first few metres of the subtidal could also limit the abundance of M. glacialis.

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[ES]Se diseña un árbol operativo de objetivos, desde uno genérico, del campo de aplicación de los espacios protegidos, jerarquizado en estratos. De arriba abajo, en el árbol, se suceden los estratos correspondientes al fin, a las metas, a las estrategias y a los objetivos de base. El diseño de itinerarios justificados de metas con sus estrategias, desde el árbol genérico operativo de objetivos asumido, desarrolla la vehiculación (armazón) del Plan de Manejo a redactar, compatible con una gestión integral del marco geográfico involucrado. Se obtiene la eficiencia y el alcance de esta vehiculación del Plan de Manejo a partir de un diagnóstico ambiental de situación, sustentado por un Análisis DAFO cuantitativo, y por una Evaluación de Impactos Ambientales heredados.