The relationship between geographical patterns of taxonomic and phylogenetic diversity in Caatinga birds

Analyzing diversity in geographic space is an effective tool for conservation strategies. Several papers investigate the relationship between taxonomic and phylogenetic diversity, where most suggest congruence. But few works are done in Neotropical environments or do not investigate different scales. Thus, we aimed to investigate the relationship between taxonomic and phylogenetic diversity patterns in the alpha and beta components of Caatinga birds. We used some criteria on the distributions collected from Bird Life International, selecting 405 species where we projected in the scales 1ºx1º, 0.5ºx0.5º and 0.25ºx0.25º. We structured phylogenetic communities using trees from BirdTree, Ericson and Hackett topological sources. For alpha diversity we quantify the number of species in each cell and for beta diversity we use the Sørensen index which uses the sum of Simpsom dissimilarity (turnover) and nestdness. To identify patterns of phylogenetic diversity, we used metrics that correspond to phylogenetic diversity (PD), mean pairwise distance (MPD) and mean nearest taxon distance (MNTD), always eliminating the effect of richness. From this, we use Pearson’s correlations to answer if the taxonomic patterns of diversity correspond to the phylogenetic ones. Although there are differences when scales and different topological sources in the alpha component are correlated PD with MPD and PD with MNTD in addition to MPD richness except in Ericson 1°. Finally the taxonomic beta diversity is correlated with beta PD and alpha PD correlated with beta MPD. Our findings indicates that the number of species is correlated with the number of phylogenetic differences.