Abstract Detail

Biogeography

Areas of Endemism of Plants in Southcentral and Southwestern Nearctic Region.

The history and connections of the flora of south central/southwestern (SC/SW) North America have been studied and summarized in biogeographic regionalization. However, some studies show contrasting delineations of the SC/SW North American provinces that could be better determined using quantitative methods, such as endemicity analysis (EA). We aimed to find spatial patterns of a set of plants in SC/SW USA by conducting EA on different scales. We first built a dataset with 81,965 specimen point records of 400 species of 174 genera and 61 families of angiosperms and 2 genera of gymnosperms using digitized specimen data from iDigBio. We then performed EA at four different scales to identify the areas of endemism (AEs). We obtained 28 AEs with different cell sizes by selecting each AE under the grid size that yielded the highest number of high scoring species. The study region split into two significant centers of accumulation of nested or partially overlapping AEs: the SW and SC consensus areas. In these parts of the Nearctic region, many genera/clades, among those in the dataset, showed a geographic split into western and eastern clades. The split corresponded to an environmental and physical barrier known as Cochise Filter Barrier. The Sonora–Mojave arid center, parts of South Texas, and the Chihuahuan desert harbor basally branching taxa of several genera and even families, based on the observations of some species, which allowed identification of the AEs.

1 - McMurry University, Biology, McMurry Station Box 368, Abilene, TX, 79697, United States

Keywords:
areas of endemism
biogeographic patterns
Madrean
SW Deserts
regionalization.

Presentation Type: Oral Paper
Number: BIOG I011
Abstract ID:256
Candidate for Awards:None