Spatial phylogenetics of the flora in the Sierra Madre del Sur, Mexico: Evolutionary puzzles in tropical mountains

Abstract

AbstractAimTo test explicitly whether the Sierra Madre del Sur includes areas with significant neo‐, paleo‐ and mixed endemism and to explore possible environmental drivers implied in their high species richness and spatial phylogenetic patterns.LocationSierra Madre del Sur, Mexico.TaxonVascular plants.MethodsSpecies richness, species endemism, phylogenetic diversity and phylogenetic endemism were analysed through a categorical analysis of neo‐ and paleo‐endemism for a set of 91493 unique records. Nonparametric Kruskal–Wallis tests for multiple comparisons of environmental variables among phylogenetic endemism categories were conducted.ResultsThe area includes 9524 species with 1133 endemics. The spatial distribution of species richness, endemism and phylogenetic metrics is heterogeneous. Species richness has a strong correlation with weighted endemism and weighted phylogenetic endemism. Neoendemism is mainly concentrated in the pine‐oak forest at higher elevations, paleo‐endemism in pine‐oak forest and seasonally dry tropical forest at lower elevations; mixed and super‐endemism were located in the cloud forest and its ecotones with the pine‐oak forest, tropical rain forest and seasonally dry tropical forest. The Kruskal–Wallis test showed significant differences only for elevation, precipitation and temperature.Main conclusionsThe Sierra Madre del Sur includes areas of neo‐, paleo‐ and mixed endemism heterogeneously distributed, representing an evolutionary puzzle of phylogenetic diversity promoted by environmental complexity. Recent diversification is suggested for areas of neoendemism, mainly in regions of pine‐oak forest and seasonally dry tropical forest, where elevation, seasonality and precipitation are variable. Areas of paleo‐ and mixed endemism indicate the preservation of ancient lineages in cloud forest and tropical forest. The Sierra Madre del Sur represents an intricate scenario for the diversification of Neotropical flora, with singular elements diverged in situ and others migrated and preserved in climatic and adaptative refugia through time.