Abstract Detail

Biogeography

Manos, Paul [1], Meireles, Jose Eduardo [1].

Biogeographic analysis of the woody plants of the Southern Appalachians: implications for the origins of a regional flora.

We investigated the origins of 252 Southern Appalachian woody species representing 158 seed plant clades to analyze larger patterns of biogeographic connectivity around the North Hemisphere. We tested hypotheses regarding the timing of species disjunctions to eastern Asia and between areas of North America. We delimited species into biogeographically informative clades, compiled sister-area data, and generated graphic representations of area connections across clades. We calculated species diversity within clades and plotted divergence times. 44% of the total species diversity was distributed among 25 North American endemic clades. Sister taxa within eastern North America and eastern Asia were proportionally equal in frequency, accounting for over 50% of the sister-area connections. At increasing phylogenetic depth, connections to the Old World dominated. Divergence times for 65 clades with intercontinental disjunctions were continuous, whereas 10 intra-continental disjunctions to western North America and nine to eastern Mexico were temporally congruent. Over one third of the clades have likely undergone speciation within the region of eastern North America. The biogeographic pattern for the region is asymmetric, consisting of mostly mixed-aged, low-diversity clades connecting to the Old World, and a minority of New World clades. Divergence time data suggest climate change in the Late Miocene to Early Pliocene generated disjunct patterns within North America. Continuous splitting times during the last 45 million years support the hypothesis that widespread distributions formed repeatedly during favorable periods, with serial cooling trends producing pseudocongruent area disjunctions between eastern North America and eastern Asia.

1 - Duke

Keywords:
Flora
Phylogeny
eastern deciduous forest
phytogeography.

Presentation Type: Oral Paper:Papers for Topics
Session: 59
Location: Salon 3/The Shaw Conference Centre
Date: Wednesday, July 29th, 2015
Time: 11:15 AM
Number: 59012
Abstract ID:894
Candidate for Awards:None