Background:

Geophytes, plants with underground perennating organs that lose their aerial organs annually, are able to survive in harsh habitats. This life form is common in the monocots that inhabit Mediterranean climates around the world. In Mexico only the northern area of Baja California has this type of climate.

Hypothesis:

In this study, we recorded the species and distribution of Mexican geophyte monocots to pinpoint diversity hotspots. Our hypothesis is that the highest diversity of geophytes will be found in biogeographic areas with complex topography and seasonal climate not only in the north of the Baja California Peninsula.

Data description:

Records of geophytes were taken from different sources, collections, taxonomic references and diversity databases. Geophyte locations were mapped in the context of biogeographic and protected areas. Climate preferences were estimated using bioclimatic variables and by a Principal Component Analysis we identified the most significant variables explaining distribution of geophytes.

Results:

The Mexican geophyte flora is composed of 476 species, approximately 10 % of the total diversity of monocots. Echeandia and Tigridia were the two most diverse genera. This flora is dominated by the taxa of Orchidaceae, Asparagaceae and Iridaceae, and ten small endemic genera were recorded. Geophyte diversity was highest in two biogeographic provinces: the Trans-Mexican Volcanic Belt and the Sierra Madre del Sur, in dry forests such as oak-pine, seasonally dry tropical forests and semi-arid shrubby vegetation. Three bioclimatic variables: temperature seasonality, annual precipitation and precipitation of the wettest quarter resulted significant for understanding distribution of geophytes.

Conclusions:

Areas sustaining a high diversity and endemism of geophytes are located in the Mesoamerican Biodiversity Hotspot, in unprotected and threatened areas. Our results suggest that geophytes are able to grow in different climates but in areas with marked temperature seasonality and variation of annual precipitation.

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