Evolutionary history of the flora of Mexico: Dry forests cradles and museums of endemism

Abstract

Mexico is considered an exceptional biogeographic area with a varied endemic flora, however spatial phylogenetic measures of biodiversity have not yet been estimated to understand how its flora assembled to form the current vegetation. Patterns of species richness, endemism, phylogenetic diversity, phylogenetic endemism and centers of neo-and paleo-endemism were determined to examine differences and congruence among these measures, and their implications for conservation. Of 24 360 vascular plant species 10 235 (42%) are endemic. Areas of endemism and phylogenetic endemism were associated with dry forests in zones of topographic complexity in mountain systems, in deserts, and in isolated xeric vegetation. Every single locality where seasonally tropical dry forests have been reported in Mexico was identified as an area of endemism. Significant phylogenetic diversity was the most restricted and occurred in the Trans-Mexican Volcanic Belt and in the Sierra de Chiapas. Notably, the highest degree of phylogenetic clustering comprising neo-, paleo-, and super-endemism was identified in southernmost Mexico. Most vascular plant lineages diverged in the Miocene (5-20 mya) when arid environments expanded across the world. The location of Mexico between two very large landmasses and the fact that more than fifty percent of its surface is arid favored the establishment of tropical lineages adapted to extreme seasonality and aridity. These lineages were able to migrate from both North and South America across Central America presumably during the Miocene and to diversify, illustrating the signature of the flora of Mexico of areas of endemism with a mixture of neo-and paleo-endemism.

Spatial phylogenetics of the Chinese angiosperm flora provides insights into endemism and conservation

“…Closely related organisms often share an evolutionarily conservative habitat preference, thus the organisms living together in a particular habitat will tend to be more closely related than expected by chance. Past studies [21,28,29,32] have shown that this was especially prevalent in dry habitats, a pattern which was confirmed here. Significantly low PD was observed in arid areas using both phylogram and chronogram, suggesting another potential explanation for the phylogenetic clustering: recent diversification in situ.…”

“…Mishler et al [12] proposed an integrating method called categorical analysis of neo-and paleo-endemism (CANAPE) to quantitatively distinguish between centers dominated by neo-endemism (range-restricted short branches) or paleo-endemism (range-restricted long branches). PE and CANAPE methods add an evolutionary perspective to understanding endemism and have drawn substantial attention [21][22][23][24][25][26][27][28][29][30][31][32][33]. Finding concentrations of endemic taxa and rangerestricted OTUs provides a critical basis for conserving evolutionary history [5].…”

Unraveling the extreme morphological variation in the neotropical Ficus aurea complex (subg. Spherosuke, sect. Americanae, Moraceae)

“…7A, 7C) indicate a similar rainfall regime in the localities where F. aurea and F. isophlebia occur, while populations from F. cookii and F. tuerckheimii occur in distinct conditions. Ficus cookii is found in a restricted habitat belonging to the Central Depression of Chiapas (Mexico), which is a center of plant diversity and endemism (Sosa et al, 2018). Regarding F. tuerckheimii , this species reaches the highest elevations and values of mean annual precipitation that can be found in the F. aurea complex.…”

Long distance dispersal in the assembly of floras: A review of progress and prospects in North America

“…As with Florida, the Neotropical flora at the tip of the Baja California is also likely to have been profoundly shaped through relatively recent dispersal events (Sosa et al, 2018) due to being discontinuous with other Neotropical areas ( Fig. 1) and for its history of inundation by the sea (Durham & Allison, 1960).…”