Utilización de la cartografía de unidades paisajísticas como recurso pedagogíco en educación ambiental

La construcción de mapas de unidades ambientales a partir de imá­genes constituyen un método de análisis medioambiental apropiado para incluirse en planes pedagógicos multidisciplinares orientados hacia la consecución de escalas de valores personales sobre el medio ambiente. Esta técnica permite conocer el funcionamiento básico de los ecosistemas de forma global, sin que para ello se requiera una metodología complicada de estudio.This study makes use of environmental unit maps from images to develop skills for identifying environmetal problems by man. This method seems suitable for being included in multidisciplinary pedagogic plans clarif­ying values about ecological process involved in the environment. Also provi­ de information to know the role of his own activity in the Nature.peerReviewe

Changes in Land Management of Iberian Rangelands and Grasslands in the Last 60 Years and their Effect on Vegetation

Rangelands and grasslands occupy now more than 3 million ha in the Iberian Peninsula representing one of the most valuable ecosystems. They are particularly interesting due to their great geographical spread and heterogeneity in land management. Significant changes have been undergone in the last 60 years affecting vegetation. The main goal in this study was to compile existing information about the changes in the Iberian rangelands and grasslands, their geographical distribution, typologies, main characteristics as well as past and recent land management based on a thorough bibliographical review and serious research. This has been subdivided into five large groups according to climate and human drivers: (1) Mediterranean rangelands and steppes, (2) oceanic grasslands, (3) mountainous meadows, (4) semi-arid steppes and (5) Portuguese rangelands and grasslands. Two milestones over the past 60 years were remarkable as main driving forces: rural exodus in the 1960s and 1970s and Spain and Portugal joining the European Union in 1986. They have provoked both processes of intensification and extensification at the same time on different scales. Many farms have been progressively fragmented using wire fences, and the numbers of livestock have been significantly increased. Land abandonment and grazing exclusion have provoked a large shrub encroachment of species such as Retama sphaerocarpa or Cistus ladanifer

La fotografía aérea en España y su aplicabilidad al seguimiento y la estimación de la erosión por flujo concentrado

Son numerosos los trabajos que muestran la creciente preocupación por los procesos de erosión hídrica por flujo concentrado en los países mediterráneos en los últimos años. Los métodos y técnicas existentes para el seguimiento y cuantificación de la erosión hídrica por flujo concentrado son muy diversos, resultando de especial interés, relevancia y potencial aquellos relacionados con las modernas tecnologías geoespaciales (sistemas de posicionamiento global diferenciales, equipos laser terrestres o aerotransportados, fotogrametría digital aérea y terrestre, etc.). Sin embargo, la utilización de dichas técnicas en numerosas ocasiones se encuentra limitada por la fecha de aparición del instrumental, por tanto, algunas fuentes históricas son todavía necesarias para comprender la evolución a medio y largo plazo de las formas de erosión por flujo concentrado. Sin embargo, en ocasiones, la localización de las fotografías aéreas existentes para una determinada zona puede resultar laboriosa y tediosa lo que da lugar a grandes pérdidas de tiempo en los proyectos y equipos de investigación. Por todo ello, los principales objetivos del presente trabajo son i) presentar una guía respecto al material fotográfico aéreo disponible para España, ii) resumir sus características principales y iii) analizar su utilidad para el seguimiento y cuantificación de la erosión ocasionada por flujo concentrado.Erosion produced by concentrated water flow has been highlighted as an important soil degradation phenomenon in the Mediterranean catchment. Several kinds of methodologies and techniques have been used indeed in order to monitor and quantify erosion produced by concentrated flow, mainly those related with modern geospatial technologies (DGPS, LIDAR, LTS, aerial and terrestrial photogrammetry, etc.). However the time scale of the studies based exclusively on modern techniques is constrained by the date of appearance of those techniques. Therefore, some historical sources are still necessary in gully erosion studies (medium, short time scale). Sometimes, however, finding these documents is laborious and tedious, being the researchers forced to spend a lot of time in localizing and acquiring it. Therefore, the main objectives of this work are i) to provide a guidance regarding the available aerial photographs and orthophotographs for rill and gully erosion studies in Spain and covering the whole country, ii) to summarize the main characteristics of these materials and iii) to analyze the suitability of using these materials for soil loss monitoring and assessment produced by concentrated flow

Studying the influence of livestock pressure on gully erosion in rangelands of SW Spain by means of the UAV+SfM workflow

Gully erosion in agrosilvopastoral systems of SW Spain represents a common degradation process, but has been hardly analysed. The suitability of using the Unmanned Aerial Vehicles (UAV) and Structure from Motion photogrammetry (SfM) workflow to map small valley-bottom gullies in these landscapes was tested. The results showed centimetre-level accuracy. Observed strengths and limitations of the UAV+SfM workflow in the study areas are discussed. The resulting cartography allowed mapping soil erosion forms at outstanding spatial scales. All study areas showed evidences of degradation

Reduction of the frequency of herbaceous roots as an effect of soil compaction induced by heavy grazing in rangelands of SW Spain

Rangelands in SW Spain constitute the most extensive ranching system on the Iberian Peninsula. During the last few decades, a significant increase in livestock numbers, along with a progressive substitution of cattle for sheep, have led to land degradation processes such as the reduction of grass cover and increased soil compaction in heavily grazed areas. Nevertheless, a better understanding of how soil compaction affects grass production is still needed. In this study, some of the effects of soil compaction due to heavy grazing are analysed, mainly the reduction of the frequency of herbaceous roots and its relationships with bulk density and soil penetration resistance. The study was carried out in 22 fenced areas grazed under different intensities (animal stocking rates: 0.19-15.76 AU ha−1). Undisturbed soil core and bulk samples were collected at 3 depth intervals in order to determine select soil properties (texture, organic matter content, and bulk density). Additionally, soil penetration resistance was quantified at 890 random points at different depths and soil moisture contents. Frequency of herbaceous roots was estimated for each soil horizon in 47 soil profiles and categorized into 4 classes: none, few, common and many. Results showed negative relationships between bulk density (> 10 cm depth) and the content of soil organic matter from 0 to 5 cm (r =−0.061, p < 0.05) and 5-10 m depth (r = −0.824, p < 0.005). Furthermore, a tendency for decreasing mean values of soil penetration resistance as the frequency of herbaceous roots increased was also observed. The values observed confirm that soil compaction provoked by an excessive number of animals reduced the quantity of herbaceous roots. The value of 2 MPa traditionally accepted as restrictive for root growth is discussed. Findings presented here could be of interest for policy makers and farm owners to guide decisions about optimum animal stocking rates

Estructuras, ritmos y sucesión en la Comunidad de aves acuáticas del embalse de Arrocampo / Joaquín Francisco Lavado Contador.

Tesis.CRAI CIENCIAS. Instituto Euromediterráneo del Agua. 639.127 LAV est

La dehesa: estado actual de la cuestión

El presente trabajo pretende ser una síntesis de lo que se entiende con el término "dehesa", concepto muy utilizado actualmente en diversos ámbitos (políticos, económicos, académicos, etc.), pero que en ocasiones, adolece de cierta ambigüedad, puesto que hace referencia tanto a un ecosistema seminatural, a un tipo de gestión humana sobre un ambiente, a un modo de explotación de dicho sistema, etc

Procesos, factores y consecuencias de la erosión por cárcavas; trabajos desarrollados en la Península Ibérica

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Procesos, factores y consecuencias de la erosión por cárcavas; trabajos desarrollados en la Península Ibérica

Texto resumen