Saghatelyan, Anna .
A biogeographic survey of the Trans Pecos flora.
Using "Synthesis of the North American flora" software and other web resources, "Floras", maps, and checklists, a checklist of the flora of Brewster, Presidio, and Jeff Davis counties in Trans Pecos,Texas, was compiled. The distribution outlines of 1635 species (on 6912sq.km) were referred to one of the 20 general distribution patterns (geoelements). These geoelements were named as the choria in the Cronquist-Takhtajan floristic system of North America.
The majority of the species is confined to the Sonoran Province with the prevalence of Chihuahuan Subprovince subendemics extending to the Tamaulipan Subprovince (no distinct boundary with the Chihuahuan). Next is the group of Sonoran Subprovince-Chihuahuan desert species, while only a few species extend to the California Province. North Madrean distribution type (mostly in USA) had more species common with California. Montane species revealed obvious connections with the Mexican Highland Province or southern Rockies. Species of wide geographical range in the western North America or of southern Prairie Province extending west to the Rockies or Great Basin were more abundant than those of the Atlantic Region.
When compared with the geographical analysis of one of the southern regions of Armenia (Yerevan) of similar elevation range and species richness (1682 species), a much higher geographic diversity (35 geoelements) and higher species to genus index in Armenia is obvious. This can be explained by a younger age of the Trans Pecos flora and influence of the Mexican (Quercus-20 species) and South American flora as opposed to multi-directional, but more obvious east to west latitudinal floristic exchange in the Trans-Caucasian Region. Trans Pecos flora is more subtropical and connected to that of Central/South America, than Armenia to Africa due to the presence of a desert filter in South West Asia.
Not much similarity among the Madrean and Tethyan floras can be inferred from this comparison.
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1 - McMurry University, Biology, McM Station Box 368, Abilene, Texas, 79697, USA
Presentation Type: Array
Location: Boulevard B/Hilton
Date: Monday, July 9th, 2007
Time: 10:30 AM