Floristic diversity of the Tropical Rainforest in Mexico

Background: The tropical rainforest (TRF) is a type of vegetation recognized for its species diversity and the degree of human threat to which it is subjected. In America, its northernmost distribution is in Mexico, but its floristic knowledge in the country is still fragmentary. Questions: What is the magnitude of vascular plant diversity in Mexico's TRF? What are its most characteristic elements? How is this floristic richness distributed geographically in the country? Studied species: 4,936 species of vascular plants. Study site: The tropical rainforest in Mexico. Methods: The TRF in Mexico was delimited by consulting floristic-taxonomic literature on its flora and databases of herborized specimens. Subsequently, its most characteristic species were identified, and a spatial analysis was conducted using grid cells 1° of latitude and longitude. TRF richness and endemism were calculated for each grid cell, and floristic units were identified through a cluster analysis. Results: TRF was recorded in eight states of the country and within 26 grid cells. The existence of 8,353 species was documented, although 4,936 of them were selected as characteristic of this type of vegetation, 889 of which are endemic to Mexico. The grouping of the grid cells suggests the existence of four or five floristic units. Conclusions: This study presents an update on the floristic richness, endemism, and distribution of the tropical rainforest in Mexico.