Browsing by Author "Sáiz, Francisco"
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Item Análisis de las relaciones entre mesofauna antártica y algunos factores climáticos(1977) Etchegaray, Julia; Sáiz, Francisco; Hajek, ErnstThe paper investigates relative abundance, distribution and specific diversity of edaphic mesofauna in relation with soil temperature. Research was carried out on Robert Island, Copper Mine Peninsula (South Shetlands), on an altitudinal transect of 150 m from the shore inland. Along the transect three macroclimatic stations were located and 8 biological sampling stations. Samples were taken every 5 days in three layers in moss and soil and the fauna was separated with· Berlesse funnels. Density of mesofauna presents a clear stratification with higher percentages at the superficial moss layer. Collembola (98.8%) is the dominant group of the mesofauna whereas Acari represented only 1.2 percent. The two groups exhibit different patterns of distribution along the transect. Collembola was predominantly found in the lower, warmer and wetter stations, while Acari was found in drier, higher and colder areas.Item Estudio de la taxocenosis muscinal de la península Fildes (isla Rey Jorge, Shetland del Sur)(1977) Pizarro, Carlos; Sáiz, FranciscoTwenty-eight musci species (Bryophyta) distributed in 16 Genera from Peninsula Fildes (King George Island, South Shetland Islands) are analysed both qualitatively and quantitatively, considering their dependence to: altitude and diversity of substrate, exposition and slope. The following parameters, measured by the indexes indicated in parenthesis, were considered: relative abundancy, spatial constancy, affinity (Jaccard and Winer), diversity (Shannon), uniformity (Pielou) and overlap (Horn). It is concluded as follows: The soil's substrate and the northern exposition increase the complexity of the muscinal taxocenosis; and the whole rock's substrate are clearly defining a taxonomic and biocenotic uniformity of musci. Five species are the most important, from an ecological point of view, in the analysed area: Drepanocladus uncinatus, Andreaea gainii, Tortula excelsa, Grimmia antarctica and Polytrichastrum alpinum. Six nuclei of species, with a high degree of affinity appear clearly defined, which are: Ceratodon minutifolius + C. grossiretis; Tortula grossiretis + T. g. varo atrata + Brachythecium turquetii; Schistidium apocarpum + Bryum sp. 2; Polytrichum alpestre + P. Juniperinum + Brachythecium antarcticum + Chorisodontium aciphyllum; Pollia heimii + Bartramia patens; Tortula tenella + Grimmia antarctica.