Análisis del paisaje para la evaluación ecológica rápida de alternativas de relocalización de una ciudad devastada

Abstract

After the eruption of the Chaitén Volcano (Chile) and the destruction of the neighboring Chaitén city, some alternative sites were evaluated for the relocation of administrative facilities and housing for the displaced. Three towns (Fandango, Santa Bárbara and Bahía Pumalín) were evaluated by means of a multi-criteria analysis, including the impact that a new urban development would have on local biodiversity. This impact was evaluated through a landscape analysis. The landscape attributes studied were (1) composition and representation of each ecosystem type, (2) connectivity, and (3) environmental value, based on a classification of the prevailing ecosystems and their respective stages of succession, defined as a function of ecosystem heterogeneity and maturity. Landscape metrics were calculated from LANDSAT 5 satellite imagery (November 17 th, 2008) with ArcView® 3.2 (ESRI) and Fragstats, including the surface co ver of each ecosystem type, the number of patches and the cohesion index (CI). Environmental value was determined qualitatively in situ. Santa Barbara was selected by authorities as the best place for New Chaitén City. Over 70 % of this is area is covered by forest, achieving a high degree of forest connectivity (CI > 99.0) and shrubs (CI > 94.0), with an advanced stage of succession, a high level of heterogeneity (species and strata) and a high level of inland environmental value. On the coast, Santa Bárbara has anthropic influence, but maintains an advanced state of succession, a high level of heterogeneity, and a medium-high degree of environmental value. Regarding the future urban development at this location, the recommendations were: maintenance of riverside integrity and the continuity of forests in Santa Bárbara. The proposed methodology proved to be: (1) useful for biodiversity assessment, despite the lack of information at species level, (2) easily replicable, due to the use of standard categories (ecosystem types) and easier access to satellite images, and (3) able to integrate environmental criteria at early stages of decision making in land use and urban planning processes.