Revista Chilena de Historia Natural 84 (2): 181-194, 2011
Landscape analysis for rapid ecological assessment of relocation alternatives for a
devastated city
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 17th, 2008) with ArcView® 3.2 (ESRI) and Fragstats, including
the surface cover 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
Key words:
Chaitén,
environmental assessment, land use change, urban development, urban ecology
