Background and Aims:

The genus Dasylirion is endemic to North America and is often overexploited for distilling sotol and for other culturally important uses. As a result of these, its natural populations have been reduced, therefore making research on its diversity and distribution patterns essential for conservation. The aims of this study were to analyze the richness, geographical distribution, endemism, and vulnerability status of Dasylirion.

Methods:

A database with 1652 unique records was built through a review of herbaria and digitized collections. The data were analyzed using Geographic Information Systems to evaluate species richness by political divisions, ecoregions, vegetation types, and protected natural areas (PNA). Additionally, richness and endemism were assessed using a grid with 60 × 60 km cells.

Key results:

Dasylirion includes 23 species and occurs from northern Oaxaca to the southern United States of America. Dasylirion is known from 20 Mexican states; San Luis Potosí has the greatest richness, followed by Chihuahua, Coahuila, and Zacatecas. The genus most frequently inhabits xeric shrublands in ecotones with coniferous and Quercus forests. Their highest diversity is concentrated in the Sierra Madre Oriental, where two richness areas were found: the Gran Sierra Plegada and the arid zone between Querétaro and Hidalgo. The endemism centers identified through different analyses are also within these ecoregions. At least seven out of the 23 species are at extinction risk, and only 16 are sheltered in PNA.

Conclusions:

Populations of different Dasylirion species are threatened due to excessive extraction. The results of the present study show the importance of developing conservation strategies based on the identification of priority conservation areas for Dasylirion, since the first step in this is to identify patterns of richness and endemism.

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