Browsing by Subject "dehesas"

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    El impacto de la ganadería y la agricultura en los ecosistemas terrestres.-Grazing and soil erosion in dehesas of SW Spain
    Schnabel, S.; Gómez Gutiérrez, A.; Lavado Contador, J.F; Universidad de Murcia
    ABSTRACT Water erosion and its relation to livestock grazing in semi-arid to dry subhumid Mediterranean rangelands with a disperse tree cover is analyzed, based on a variety of studies carried out since 1990 in Extremadura, Spain. The dominant factors of sheetwash are rainfall intensity and soil surface cover, the latter being controlled by rainfall amounts and livestock density. The discontinuous valley bottom gullies present a complex relationship with catchment hydrology. Giving the high temporal variability of sediment losses, the influence of livestock on gully erosion is difficult to determine with short-term studies. Analysis of aerial photographs (1945–2006) of the Parapuños study catchment point to an enhanced gully activity during the last decade as a consequence of increased livestock numbers.
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    El impacto de la ganadería y la agricultura en los ecosistemas terrestres.-The availability of water in ranches of mediterranean type climate
    S. Schnabel; Pulido Fernández, M.; Lavado Contador, J.F.; Universidad de Murcia
    ABSTRACT A preliminary study on water resources for livestock rearing in SW Spain is presented. The objectives of this work were to assess the availability of water for domestic animals in farms and to explain whether water shortages are controlled by environmental factors or are also related with land management. The study was carried out in 54 private farms of wooded and treeless rangelands in Extremadura. Field work, digital topographic maps and aerial photographs were used to assess the potential hydrological resources of each farm. The water needs of livestock were estimated considering the number and species of animals per farm, as well as other factors influencing their water consumption. Furthermore, semistructured interviews were carried out in order to gather information about water management. Results indicate that almost 20% of the farms suffer problems of water availability in summer and almost 50% during droughts. Different solutions are adopted by the farmers, including construction of infrastructure, bringing water from outside or moving the animals to other areas. Data indicate a positive relationship between problems of water supply and the degree of aridity. Data also point to a relationship with water consumption by livestock and the availability of water by artificial ponds.