Details

Autor(en) / Beteiligte

• Bresowar, Gerald E

Titel

Recent divergence and complex history: Oreocarya paradoxa and Oreocarya revealii in the Colorado Plateau

Ort / Verlag

ProQuest Dissertations Publishing

Erscheinungsjahr

2014

Link zum Volltext

• ProQuest

Quelle

ProQuest Dissertations & Theses A&I

Beschreibungen/Notizen

• The Colorado Plateau of western North America is a province rich in plant endemism, and yet the evolutionary patterns influencing this high endemism has been only studied in a few plant taxa. Here we investigate the evolutionary histories of two endemic plant species found in the northern portion of the Colorado Plateau Provence. These species are located in the taxonomically and genetically difficult genus Oreocarya (Boraginaceae), which has its center of species diversity in the Colorado Plateau and Great Basin regions. Oreocarya paradoxa is a relatively widespread, though not common, species found on a variety of calcium-containing soils in Utah, western Colorado, and northern New Mexico and Arizona. It is described as sister to the rare species O. revealii, which is seemingly restricted to gypsum soil types, and which shows growth form variation separating it from O. paradoxa. This research assessed the evolutionary relationship between these taxa using phylogenetic, network, and population genetic approaches using nuclear, chloroplast, and microsatellite data from a large geographic sampling of both study taxa. Key findings from this research are support for the evolutionary sister species status of the study taxa, along with evidence of recent genetic divergence which has only become complete in the very recent past. The genetic identity of O. revealii does not correspond to gypsum soil habitats or the gypsum-associated growth form, and indeed, several gypsum type populations were identified as being genetically aligned with O. paradoxa. The geographic distribution of O. paradoxa is genetically disjunct, and the overall evolutionary story of these two species is one of regional and population-level genetic isolation. Only a subset of what originally was described as O. revealii are assigned to this taxonomic circumscription based on the genetic data. This research informs conservation and land management of O. revealii in the Colorado Plateau.