A new methodology to quantify structural landscape impacts of land use/land cover change using moving window metrics: a case study in a Chilean coastal basin

Land use and land cover changes (LULC) result in alterations to landscape structure, with particularly significant consequences in the landscapes of coastal basins due to their unique characteristics and special sensitivity. The aim of this work was to introduce a new methodology to assess the impacts of LULC transitions on landscape structure in a coastal basin of the Los Ríos Region in Chile. Changes in landscape patterns were assessed by analysing systematic transitions in conjunction with moving windows landscape metrics and spatial cluster analysis. An index measuring the impact of transitions on landscape structure change (ITSC) was calculated to assess the degree to which each systematic transition contributed to the spatial cluster of landscape change. The proposed method showed that transitions resulting from the replacement of native forest and especially those which involve its transformation into forestry plantations, have the greatest potential impact on landscape structure in the basin. Therefore, planning and management measures must be established to prevent such transitions, so avoiding a massive change in landscape structure.Comunidad de MadridFondo Nacional de Desarrollo Científico y Tecnológico (Chile

Dinámica del paisaje para el período 1980-2004 en la cuenca costera del Lago Budi, Chile : Consideraciones para la conservación de sus humedales

The landscape corresponds to a complex, open, space-time system, intermediate between nature and society. Its conditions and dynamics are determined by natural processes and human presence in which local and regional alterations modify ecological processes and patterns of biodiversity. Conspicuous in the Budi lake/river basin landscape are continental wetlands and marshy bodies of water and forests. Conflicts have arisen due to substitution and land-use change. Using the framework and scale of analysis of landscape ecology, the landscape dynamics of the Budi lake/river basin has been analyzed as an input for ecological planning of this area and conservation of its wetlands. Studies of variation of areas destined for different uses and land cover, as well as rate of change starting from category maps drawn up on the basis of photo-interpretation of aerial photographs of the area under study taken in 1980, 1994 and 2004, were done. Eight landscape types were identified, starting from previously drawn up classifications of ground cover and land-use. We also evaluated the variation in landscape patterns through the application of 21 measuring processes related to typology and surface, perimeters, shapes, diversity, aggregation and adjacency as indicators of landscape dynamics and evolution, which were applied in three levels: patches, classes and total landscape area. Among others, results showed a significant increase of the area of riverside wetlands (3,039.7 hectares in 1980 compared to 4,384.8 hectares in 2004), and a decrease in clear- water surface area. Furthermore, in the last 30 years there were increases in forestry plantations, of 17.6% between 1980 and 1994, and of 27.2% between 1994 and 2004; meanwhile, farming and cattle-raising have steadily decreased. Also, an increase in the number of patches and a decrease in their average size (except for wetlands), an increase in the total perimeters, and a decrease of distances between neighbours were assessed; all of which points to a landscape which is undergoing a process of fragmentation, with patches interspersed within the dominant pattern. The analysis carried out defines a system of wetlands having high connectivity with the contributing watersheds, spatial heterogeneity and intermixing of classes, in which current watershed uses are affecting the evolution of riverside areas. These indicates the extent of alteration of the system as well as the importance of the anthropogenic variable in its evolution; factors to be taken into account during the decision-making process of future proposals for land-use regulations involving control of sedimentation, protection of vegetation and maintaining connectivity

Determinación del nivel de antropización de humedales como criterio para la planificación ecológica de la cuenca del lago Budi, IX Región de La Araucanía, Chile

The level of human impact on the wetlands of the Lago Budi Basin was established, as a function of the degree of alteration to the basin and the degree of alteration to the wetlands. The former was evaluated on the basis of a spatial analysis of the fragility and stability of the hydrographical basin. The latter through a modified impact model, with a panel of experts who evaluated the fulfilment of the wetlands' function and their state. Four principal types of wetlands were recognized: estuarine, meadow, waterside and marshy. It was found that 98% of the total surface presents a high degree of alteration, as determined by its instability and fragility. Farm use was weighted as the principal agent of alteration of the wetlands' functions, with 61% of this showing alteration in the maximum degree. This evaluation makes it possible to differentiate areas and generate base criteria for the conservation of wetlands in the basin.Se determinó el nivel de antropización de los humedales de la cuenca del Budi, en función del grado de alteración de cuencas y el grado de alteración de humedales. El primero, evaluado a partir del análisis espacial de la fragilidad y estabilidad de la hoya hidrográfica. El segundo, a través de un modelo de impacto modificado, con panel de expertos que valoró el cumplimiento de funciones de humedales y su estado. Se reconocieron principalmente 4 tipos de humedales: estuarino, palustre, ribereño y de marisma. Por otro lado, el 98% de la superficie total presenta altos grados de alteración, determinados por su inestabilidad y fragilidad. El uso agrícola fue ponderado como el principal agente de alteración de las funciones de los humedales, presentándose un 61% de estos en categoría de máxima alteración. La evaluación realizada permite discriminar áreas y generar criterios de base para la conservación de humedales en la cuenca

Morphology and dune dynamics in the coastal border of Araucania region in Chile : Background for conservation and territorial management

An evaluation was made of the dynamics of the dune systems of the coastal strip of the Araucanía region between 1994 and 2004, based on its morphological classification and degree of stabilization as evaluated from cartographic material, aerial photographs and investigation in the field. Eight fields of dunes were defined with a total surface area of 4,597 ha being stated a total expansion of 314 ha in the period; active dunes represented 35% of the total area, while semi-stabilized and stabilized dunes represented 31% and 15% respectively. The most common type of morphology was transverse dunes and the most frequent plant species were Pinus radiata and Ammophila arenaria. Finally, the localization and the determination of the stabilization grades and dunaries shapes allow to recognize the action of the natural and anthropic factors, these integrally require to be tackle as a frame for an integrated management of this coastal zone.Se evaluó la dinámica de los campos dunarios del borde costero de La Araucanía entre los años 1994 y 2004, usando para ello la clasificación morfológica y grado de estabilización, evaluado a partir de material cartográfico, fotografías aéreas y reconocimiento en terreno. Se delimitaron 8 campos de dunas distribuidos en una superficie de 4.597 ha, constatándose una expansión total de 314 ha en el periodo; las dunas activas representaron un 35% de esta superficie, mientras que las dunas semiestabilizadas y estabilizadas representaron un 31 y 15% respectivamente. La morfología más frecuente fue el tipo de duna transversal y las especies vegetales con mayor frecuencia fueron Pinus radiata y Ammophila arenaria. Finalmente, la localización y la determinación de los grados de estabilización y formas dunarias permiten reconocer la acción de factores naturales y antrópicos, los que requieren ser abordados integralmente como base para una gestión integrada de esta zona costera

Cambios en la organización económico-espacial de la fruticultura en territorios de La Araucanía, Chile

El artículo aborda el potencial de expansión de la actividad frutícola en la región de La Araucanía, identificando territorios que presentan aptitud para su desarrollo futuro. Se realiza un análisis histórico y se elabora un modelo espacial para definir áreas aptas, el resultado permite reconocer la existencia de dos territorios específicos: Malleco Norte, conformados por Angol, Renaico y Collipulli, y Cautín sur, integrado por las comunas de Freire, Pitrufquén, Gorbea, Loncoche y Villarrica, en estos espacios es posible expandir aún más la actividad pero se requiere mejorar la infraestructura e incorporar un enfoque territorial al desarrollo productivo regional