Create your own conference schedule! Click here for full instructions

Abstract Detail


Leatherman, Lila [1], Douglas, Norman [2], Olvera, Hilda Flores [3], Ochoterena, Helga [4], Moore, Michael [5].

Hit Me With Your Best Shot: Gypsum Endemism and Resistance to Pleistocene Climate Change in Anulocaulis (Nyctaginaceae).

More than 200 species of plants are restricted to the island-like exposures of gypsum (CaSO4.2H2O) that are scattered throughout the greater Chihuahuan Desert region. A recently proposed conceptual model (Harrison et al. 2009) suggests that plants that are adapted to unusual soils may be protected from competition from substrate generalist taxa during periods of climate change. As an extension of this model, we propose that gypsum endemism could have allowed arid-adapted gypsum endemic taxa to remain in place during Pleistocene glacial maxima, when cooler and wetter climates allowed piñon-juniper savannas to expand across the formerly large-scale arid regions of the present Chihuahuan Desert. We investigated this hypothesis by using species distribution modeling (SDM) to model the past and present geographic ranges of taxa within Anulocaulis (Nyctaginaceae), an arid-adapted North American genus of five species, two of which are endemic to gypsum in the Chihuahuan Desert. Compared to models for generalist taxa, SDMs for gypsum endemic taxa had significantly larger modeled modern distributions than observed modern distributions, and exhibited a modeled range during the last glacial maximum (LGM) that did not overlap the observed modern range. Because Anulocaulis lacks evident long-distance dispersal methods, it is unlikely that gypsum endemic species in the genus would be capable of dispersing rapidly during the climatic oscillations of the Pleistocene. Based on the above results, we infer that the gypsum endemic taxa are not modeled accurately by climatic variables alone, and that their geographic ranges are not constrained by climatic variables. This conclusion is supported by molecular studies that demonstrate a Miocene-Pliocene origin for the genus as well as a significant amount of geographically-correlated genetic diversity among populations. Together, these lines of evidence suggest that the gypsum endemic populations of Anulocaulis may have been able to persist relatively intact throughout the Pleistocene.

Broader Impacts:

Log in to add this item to your schedule

Related Links:
Phylogenetics and phylogeography of Chihuahuan Desert gypsum endemics

1 - Oberlin College, 119 Woodland St., Oberlin, Ohio, 44074, United States
2 - Oberlin College, Biology, 119 Woodland St., Oberlin, OH, 44074, USA
3 - Instituto de Biologia, UNAM, Departamento de Botanica, Departamento de Botanica, Mexico, DF, C.P. 04510, Mexico
4 - Instituto De Biologia, UNAM, Depto Botánica-Apdo.Postal 70-367, Coyoacan, Mexico DF, N/A, 04510, Mexico
5 - Oberlin College, 119 Woodland St., Science Center K111, Oberlin, OH, 44074, USA

Chihuahuan Desert
edaphic endemism
Climate Change
species distribution models.

Presentation Type: Oral Paper:Papers for Topics
Session: 50
Location: Magnolia/Riverside Hilton
Date: Wednesday, July 31st, 2013
Time: 5:00 PM
Number: 50014
Abstract ID:684
Candidate for Awards:None

Copyright © 2000-2012, Botanical Society of America. All rights reserved