Abstract Detail



Biogeography

Moore, Michael [1], Douglas, Norman [2], Ochoterena, Helga [3], Flores Olvera, Hilda [4].

Patterns of gypsum endemism in Coahuila.

The Chihuahuan Desert region hosts the world’s largest and most diverse flora of gypsum endemic plants. Within this region, Coahuila is one of the main centers of endemism on gypsum, with numerous endemics inhabiting the diverse gypsum landforms of this Mexican state. Surface gypsum soils are generally of four types in this area: (1) ancient bedrock gypsum that has been exposed by geological uplift and erosion, (2) recently reprecitated gypsum that has accumulated as playa deposits in and around old Pleistocene lake beds, (3) gypsum mixed with sodium salts in old Pleistocene lake beds, and (4) gypsum sand dunes. Almost all of these gypsum exposures occur in the southern half of Coahuila, in habitats ranging from desert to juniper savanna to wetlands. Recent studies of phylogeny and phylogeography in key gypsum endemic taxa have provided key insights into the evolution of the Coahuila gypsum flora, which are reviewed here. For example, these studies have begun to elucidate common patterns of diversification in the Coahuila gypsum flora, and have yielded important preliminary data on levels of gene flow among discrete gypsum “islands”. These studies also suggest potential source-sink dynamics for the colonization of lake bed deposits during the Pleistocene, and indicate that a combination of allopatric speciation and niche shifts may have been responsible for diversification in clades of gypsum endemics in Coahuila. Finally, these studies suggest that the gypsum endemic flora in Coahuila as a whole has remained relatively stable compositionally throughout the Pleistocene, despite repeated climatic oscillations.


Related Links:
Evolution of Chihuahuan Desert gypsum endemism


1 - Oberlin College, Department Of Biology, 119 Woodland St., Science Center K111, Oberlin, OH, 44074, United States
2 - University Of Florida, Biology, PO Box 118525, Gainesville, FL, 32611, United States
3 - Instituto De Biología, UNAM, Botanica, Depto Botánica-Apdo.Postal 70-367, Coyoacan, Mexico DF, 04510, Mexico
4 - Instituto de Biología, UNAM, Apartado Postal 70-367, Mexico, DF, 04510, Mexico

Keywords:
gypsum
Coahuila
Mexico
Chihuahuan Desert
phylogeny
phylogeography
gene flow
Pleistocene.

Presentation Type: Oral Paper
Number:
Abstract ID:206
Candidate for Awards:None


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