Using phylogenetic diversity measures to set priorities in conservation: An example from southern South America

Phylogenetic diversity measures rank areas for biodiversity conservation pr iorities based on information encoded in phylogenies (cladograms). The goal of these ranks for conservation is to consider as many factors as possible that provide additional taxic information, such as taxa richness, taxa dis tributional patterns, area endemicity, and complementarity between areas. A t present there are many measures that consider phylogenetic information, i ncluding node-based, genetic-distance, and feature-based measures. We devis ed a modified phylogenetic node-based index that we call "taxonomic endemic ity standardized weight," which considers not only the taxonomic distinctne ss of the taxa that inhabit a given area but their endemicity as well. Once the standardized weight of the taxonomic endemicity identifies the area of highest priority, complementarity can be used to identify the second area and so on. We used this node-based index to rank priority areas for conserv ation in southern South America, and we compared the results of our ranking s to results based on other node-based indexes. Our index identified Santia go district, in Central Chile province, as the highest priority area for co nservation, followed by Maule, Malvinas, and districts of Subantarctic prov ince. Malvinas exhibits greater complementarity relative to Santiago than M aule does, however so Malvinas is ranked second in priority. Indexes based on phylogenetic information measure the evolutionary component of biodivers ity and allow one to identify areas that will ensure the preservation of ev olutionary potential and phylogenetically rare taxa. The modified index we propose is sensitive to taxic distinctness and endemicity as well and allow s information from diverse taxa to be combined (i.e., different cladograms) . The use of complementarity allows for preservation of the maximum quantit y of taxa in a minimal number o protected areas.