Abstract Detail


Krakowiak, Alaina [1], Harris, Jesse [2], McGlaughlin, Mitchell [3], Simmons, Mark [4].

Conservation genetics and phylogeography of a disjunct prairie plant: Clematis fremontii (Ranunculaceae).

Premise: Clematis fremontii has a unique disjunct distribution with populations found in multiple distinct and widely separated xeric limestone prairie habitats in the Great Plains, Ozarks, and Southeast. It is considered rare and endangered in much of its range. This study assesses genetic differentiation and diversity of C. fremontii in and among these disjunct areas in order to 1) better understand the biogeographic processes that shaped its current range, and 2) inform conservation strategies.
Methods: 116 samples collected from 17 populations across the species’ range plus 10 outgroup samples of C. ochroleuca were sequenced using a double digest restriction-site associated DNA (ddRAD) approach. Genetic diversity and structure were analyzed using STRUCTURE, multivariate ordination, and other statistical approaches. Phylogenetic relationships were estimated with Tetrad and a neighbor-net analysis.
Results: Analyses generally demonstrated that the greatest genetic divergence was between groups occurring east and west of the Mississippi River, but there was further structuring among disjunct regions. All populations showed moderate genetic diversity, and geographic regions showed moderate genetic differentiation from one another. We also found evidence for secondary contact between eastern and western groups, particularly in the Georgia population.
Conclusions: Our data supports the hypothesis that separation of eastern and western C. fremontii populations dates to relatively recent Pleistocene events, and did not support the hypotheses of ancient vicariance via the formation of the Mississippi Embayment or very recent expansion during the Hypsithermal Interval. We suggest that vicariance of eastern and western groups could be due to meltwater mega-floods of the Mississippi River, or an eastern expansion from a more widespread western group during an interglacial period. Our data also showed that C. fremontii accumulated genetic variation upon isolation in xeric limestone prairie habitats, similar to a rapid radiation. Small, isolated populations of Clematis fremontii had higher levels of genetic diversity than we expected, but habitat loss still poses a major threat. Further, current levels of genetic diversity could indicate an extinction lag. Restoration and population augmentation efforts are needed for this species to persist in the long term.

1 - Colorado State University, 1719 Morningside Dr., Fort Collins, CO, 80525, United States
2 - University of Colorado Boulder, Boulder, CO
3 - University of Northern Colorado, Greeley, CO
4 - Colorado State University, Department of Biology, Fort Collins, CO

none specified

Presentation Type: Oral Paper
Number: BIOG III003
Abstract ID:968
Candidate for Awards:None

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