Examinando por Materia "HIDROLOGIA"

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    Artículo
    Crack willow changing riverine landscapes in Patagonia
    (Wiley, 2017) Datri, Leonardo; Faggi, Ana; Gallo, Leonardo Ariel
    In Patagonia (Argentina) in recent decades, the exotic species and hybrids of Salix alba - Salix fragilis complex has spread over wide areas along watercourses, taking advantage of it is sexually and vegetatively propagation. It out-competes with native vegetation, facilitated by stochastic events related to large floods of long-lasting duration higher than the average maximum of 186 m3/sec for more than a day. We analysed the exotic willow’s increase along the braiding Azul River, and the hydrological regime between 1966 and 2012. We evaluated the links between regime and tree density over time using dendrochronological data. Results showed an increase of the forest’s cover from 2.1% to 70.8% over the last 46 years. The densities of exotic willows grew exponentially between 1966 and 1973, during a period which was free of higher floods. The initial native populations declined as willow’s population increased. Up to 1973 there was an increase in the native populations too. Then from 1974 on, the willow showed a gradual growth coupled with a decline in the native trees. Up 1977 the willow expansion could be linked to an extreme flood that reached 392 m3/sec (210.75%) greater than the average of the maximum flows). We concluded that plant succession in the Azul River follows a “Red Queen” effect whereby the exotic willow and native trees repeatedly reorganized the system after pulses and periods of extreme flooding events.
  • Miniatura
    Parte de Libro
    Parte B : características de la cuenca del río Reconquista : aspectos geográficos y ambientales
    (Fundación de Historia Natural Félix de Azara, Argentina, 2021) Basílico, Gabriel Omar
    El Área Metropolitana de Buenos Aires (AMBA) es un territorio heterogéneo y complejo atravesado por un gran número de cursos de agua, entre los que se destacan los ríos Luján, Reconquista y Matanza-Riachuelo. En este capítulo se describirán algunas características del río Reconquista y su cuenca de drenaje. La densidad de población, los usos del suelo, la flora y fauna presentes y la calidad de las aguas superficiales, entre otras características, permiten distinguir dos sectores marcadamente diferentes dentro de la cuenca: la cuenca alta, que aún conserva similitudes con el paisaje original de llanura Pampeana y las cuencas media y baja, sector completamente urbanizado y modificado. Se pone de relieve la necesidad de preservar los valores biológicos, paisajísticos y culturales de la cuenca alta, pero también la posibilidad de remediar y rehabilitar los ambientes de las cuencas media y baja.