Browsing by Author "Dias, J.A."
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- Beach morphodynamic impact on a macrobenthic community along a subtidal depth gradientPublication . Dolbeth, M.; Ferreira, Oscar; Teixeira, H.; Marques, J. C.; Dias, J.A.; Pardal, M. A.The subtidal macrobenthic community of a temperate beach in southern Portugal was studied along a depth gradient (1.3 to 32 m deep), which was long enough to comprise both highly hydrodynamic and calmer areas, to assess the influence of the spatial and temporal differences in hydrodynamic impact at the seafloor on the organization of a macrobenthic community. These differences were assessed by studying the variations in wave climate, depth of closure and extension of the mixed profile. A spatial zonation was detected from highly hydrodynamic shallow depths, 7.2 m deep shorewards, to the calmer deeper areas, from 8.4 m seawards. Accordingly, in the shallowest depths, species richness and densities were lower, with the inhabiting species, mainly crustaceans and surf clams, adapted to the environmental severity. Both species richness and densities increased along the depth gradient, and the community became dominated by polychaetes, nematodes and nemerteans. Seawards, within the relict sediments (deeper than 25 m), species richness and abundance decreased again. The community patterns also changed in response to the occurrence of strongly hydrodynamic episodes (such as storms), which had a higher impact than the seasonality. It was concluded that harsh physical environmental conditions reduce species richness, both spatially and temporally. With respect to density, other parameters related to life cycle characteristics, recruitment success and biotic interactions may also have some impact.
- Contra a maré cremos,crianças, que basta edificar mais cubos e muralhas de areia: reflexões interdisciplinares sobre a gestão costeiraPublication . Freitas, J. G.; Dias, J.A.; Paula, D. P.; Cancela da Fonseca, Luis; Vasconcelos Júnior, R.; Schmidt, L.Este trabalho – que não é um artigo científico e por isso não segue a sua estrutura – reúne um conjunto de opiniões de vários investigadores que se dedicam ao estudo das zonas costeiras. A todos se pediu que reflectissem – com base na sua experiência pessoal e profissional – sobre a gestão actual deste espaço, partindo da frase do artista plástico Carlos Augusto Ribeiro, que serve de título a este texto. Aqui se discute sobre populações e saberes tradicionais, obras de engenharia costeira, gestão de conflitos, destruição de ecossistemas e insustentabilidade, necessidade de cooperação e conhecimento multidisciplinar, novos modelos de gestão do litoral e de cidadania.