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

• Autores: Peña-Cortéz, Fernando; Rebolledo, Gonzalo; Hermosilla, Katherine; Hauenstein, Enrique; Bertran, Carlos; Schlatter, Roberto; Tapia, Jaime
• Año de publicación: 2006
• Idioma: español castellano
• Tipo de recurso: artículo
• Fuente: Ecol. austral (En línea) 2006;02(016):183-196
• Materia: PAISAJE; PATRONES DEL PAISAJE; PLANIFICACION ECOLOGICA; CONSERVACION DE HUMEDALES; CAMBIO DE USO; LANDSCAPE; LANDSCAPE PATTERNS; ECOLOGICAL PLANNING; WETLANDS CONSERVATION; LAND USE CHANGE
• Institución: Universidad Nacional de Buenos Aires. Facultad de Ciencias Exactas y Naturales

Se analizó la dinámica del paisaje por medio de la variación en las superficies de distintos usos y coberturas de suelo y su tasa de cambio, utilizando mapas categóricos elaborados de la fotointerpretación de imágenes de vuelos de los años 1980, 1994 y 2004, donde se identificaron ocho tipologías en el paisaje. A su vez se evaluó la variación en los patrones del paisaje aplicando 21 métricas relacionadas a la tipología y superficie, bordes, formas, diversidad, agregación y yuxtaposición, como indicadores de la dinámica y evolución del paisaje. Se observó un aumento significativo en la superficie de humedales ribereños (3039.7 ha en 1980 a 4384.8 ha en 2004), una disminución en la superficie del espejo de agua y un aumento de las plantaciones forestales a tasas de 17.6% entre 1980 y 1994, y 27.2% para 1994 y 2004, mientras el patrón de uso agropecuario se ha visto reducido progresivamente. A nivel de patrones espaciales del paisaje, se constató un aumento del número de parches, una disminución de su tamaño promedio (salvo en el caso de los humedales), un aumento del total de bordes, y una disminución de las distancias entre vecinos, dando cuenta del estado del proceso de fragmentación en el paisaje donde los parches se encuentran entremezclados con la matriz dominante. La vinculación de estos patrones espaciales y de cambio con los procesos ecológicos, se constituye en un insumo para la toma de decisiones en el marco de la planificación ecológica y 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.