Gypsum and Plant Species: A Marvel of Cuatro Ciénegas and the Chihuahuan Desert
Soils rich in gypsum (CaSO4·2H2O) are both a challenge for plant growth and a trigger for plant evolution. Plants that grow only on this type of soils are known as gypsophiles, but there are also generalists that grow on and off gypsum, known as gypsovags. The Cuatro Ciénegas municipality (CCM) in Coahuila is characterized by a complex mosaic of soils with different gypsum contents, ranging from massive, ancient gypsum evaporite bedrock, crystalline selenite, and anhydrite to very recent formations of secondary evaporites, often mixed with other salts, and gypsum dunes. These exposures of gypsum (gypsum outcrops) host a species-rich gypsophilic flora that has mostly been described in only the last 50 years, and aside from the well-known gypsum deposits of Cuatro Ciénegas Basin (CCB) is still imperfectly known. To date there is no available comprehensive synthesis for where the gypsum outcrops occur within CCM or for the vascular plant species growing on them. In this chapter we use remote sensing techniques to reveal botanically unexplored gypsum outcrops and we present a checklist for the vascular plant species currently known to occur on gypsum outcrops within CCM. We report 297 species in 187 genera and 60 families of vascular plants growing on gypsum outcrops in the CCM, of which 31 species are gypsophiles, five are halogypsophiles (species that grow on soils with a mixture of sodium chloride and gypsum), and three are either gypsophiles or halogypsophiles; 15 are endemic to the municipality. Our results demonstrate that the method presented here for detecting potential gypsum outcrops is powerful, that CCM has an outstanding number of potential gypsum outcrops, many of which are unexplored botanically. The relatively high number of gypsophiles in CCM and the fact that new taxa continue to be discovered clearly indicate the need for continued botanical exploration of gypsum environments in the Cuatro Ciénegas region and in Coahuila and the Chihuahuan Desert as a whole.
Ochoterena, Helga, Hilda Flores-Olvera, Carlos Gómez-Hinostrosa, and Michael J. Moore. “Gypsum and Plant Species: A Marvel of Cuatro Ciénegas and the Chihuahuan Desert.” In Plant Diversity and Ecology in the Chihuahuan Desert: Emphasis on the Cuatro Ciénegas Basin, edited by Maria C. Mandujano, Irene Pisanty, and Luis E. Eguiarte, 129–165. Cham: Springer, 2020.
Part of the Cuatro Ciénegas Basin: An Endangered Hyperdiverse Oasis series.
Endemism, Gypsum, Gypsophiles, Gypsovags, Halogypsophiles