THE DISTRIBUTION OF PHYLOGENETIC DIVERSITY OF MAMMALS IN MEXICO AND ITS IMPLICATIONS FOR CONSERVATION

Abstract

The current rate of biodiversity loss has stimulated studies aimed at identifying areas of concentration of biodiversity where conservation efforts can be targeted. Phylogeny has become an important element in conservation either to preserve areas of high phylogenetic diversity (and therefore evolutionary history) or to identify species attributes that make them prone to become endangered or at risk of extinction. This dissertation dealt with the quantification of phylogenetic diversity of Mexican mammals, its geographic distribution, and its correlation with both the life history attributes of the species and selected characteristics of the environment. In order to do this, I had to construct a complete and reasonably well-resolved phylogeny of the 416 species of terrestrial mammals. This has allowed assessing the benefits and limitations, as well as the similarities and differences, of the two indices of phylogenetic information currently in use: Faith's index of phylogenetic diversity (PO) and Clarke & Warwick's index of taxonomic distinctiveness (TD). This has also allowing to evaluate the degree of correspondence between the distribution of these indices and the distribution of the natural protected areas of Mexico and to identify the minimum number of reserves (and their location) that would be required to protect all 416 species. Although these indices show a high degree of correlation, by emphasising slightly different aspects of the topology of the classification, they sometimes differ in their identification of priority areas. The results show that the value of either PO or TD is determined primarily by species-richness ( S) and secondarily by the topology of the phylogeny. In general, areas of high phylogenetic complexity (HPA, those made up of distantly-related taxa, independent of their number) are found mainly in regions traditionally recognised as worthy of conservation, such as the Transvolcanic Belt and the tropical South-East region. Comparative analysis employing the method of independent contrasts showed the correlation between different life history attributes of the species, as well as the correlation between these life history attributes and some characteristics of the environment (such as latitudinal range, average temperature and average precipitation in the distribution of each species). This permitted exploration of the benefits and limitations of life histories as subjects for conservation.