Gypsophily in tropical environments: a case study in the Yucatan Peninsula

Abstract Gypsophily, i.e. the relationship between plants and gypsum soils, has been extensively studied only in arid and semi-arid regions, in contrast to tropical areas, where gypsum outcrops act as refugia for xerothermophilic species and endemic flora. We focused on gypsophile flora in Campeche, Mexico on the Zoh-Laguna Plateau. Using a combination of remote sensing, literature review, and herbarium databases, we identified 14 potential gypsum outcrops and compiled a list of vascular plant species with the potential to grow in gypsum soils in Campeche (151 total species: three probable gypsophiles and endemic to YP, 148 gypsovags). Nine of the 14 potential gypsum outcrops remain unexplored botanically, and 18 species in the final checklist were not previously reported to have an affinity for gypsum soils. This study is the first to confirm the presence of gypsum and report its concentration in the evaluated soils; gypsum content in the soils reached 51%, much higher than the commonly accepted 25%. Our results on gypsum soils and associated vegetation confirm the need for more extensive gypsophily studies in tropical zones.