Delineation of natural landscape units for Puerto Rico

Abstract

We have classified the archipelago of Puerto Rico into a set of homogeneous and coherent natural landscape units. Such a classification may serve as the basic division of the territory for use in research or in planning and land management efforts. The landscape units defined in this work consist of homogeneous regions-in terms of their structural, functional and visual characteristics-which have been shaped by natural abiotic factors. Four variables were considered in the analysis: elevation, slope, life zones, and geology. The information from these variables was processed with non-linear Principal Component Analysis, which extracted two components. These components were used in a K-means cluster analysis to define nine landscape types (i.e., different groupings based on environmental characteristics). Two additional measures were obtained from this procedure and used in a subsequent analysis: cell membership values and the dissimilarity between landscape types. The strength of the grouping procedure was tested by using Multiple Discriminant Analysis, which found that 86 percent of the objects were correctly classified and that the whole classification process was significant. In addition, all variables were found to be significant during the classification process. The landscape types, the cell membership values, and the dissimilarity measure between landscape types were all used to delineate fourteen landscape units of the archipelago of Puerto Rico. The main island contains twelve units, while the island-municipalities of Vieques and Culebra make up two distinct units in themselves