Audrey Spencer
Ph.D. Candidate
Ackerfield & Bruederle Lab
CU Denver Department of Integrative Biology | Denver Botanic Gardens
When: Friday, April 25th, 2025, 12:00 - 1:00pm
Where: North Classroom, Room 3207
Systematics and Biogeography of the Eastern Asian-North American Disjunct Genus, Physocarpus (Rosaceae)
The contemporary distributions of species reflect their evolutionary history. Disjunctions (discontinuities in the geographic ranges of organisms) offer powerful natural systems to test hypotheses about ancient dispersal routes, putative glacial refugia, and the role of biogeographic processes like vicariance versus long-distance dispersal. Physocarpus (“ninebark”), a genus of deciduous shrubs in the rose family (Rosaceae), provides an excellent model system with which to examine disjunctions at multiple levels. The genus occupies an intercontinental disjunction between eastern Asia (EA) and North America (NA), as well as an intracontinental disjunction between eastern and western NA. For my doctoral research, I used reduced-representation genomic data to clarify the evolutionary relationships and biogeographic history of Physocarpus, while informing the taxonomy of the species comprising the genus. I investigated the development of the intercontinental (EA–NA) and intracontinental (ENA–WNA) disjunctions by inferring the timing of lineage divergence and geographic patterns of diversification for Physocarpus. The findings from my research provide insight into the timing and mode of dispersal between EA and NA for temperate lineages and have implications for the origins of the flora of the Southern Rocky Mountains.