Repository logo

Browsing by Author "McGlaughlin, Mitchell, committee member"

Now showing 1 - 1 of 1
  • Thumbnail Image
    ItemOpen Access
    Conservation genetics and phylogeography of a disjunct prairie plant: Clematis fremontii (Ranunculaceae)
    (Colorado State University. Libraries, 2022) Krakowiak, Alaina, author; Simmons, Mark, advisor; Ackerfield, Jennifer, committee member; Hufbauer, Ruth, committee member; McGlaughlin, Mitchell, committee member
    Premise: Clematis fremontii has a unique disjunct distribution with populations found in multiple distinct and widely separated mixed-grass and 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) inform conservation strategies, and 2) better understand the biogeographic processes that shaped its current range. 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. hierarchical relationships were estimated with Tetrad, TNT, and a neighbor-net analysis. Results: All populations showed moderate genetic diversity, and geographic regions showed moderate genetic differentiation from one another. Analyses generally demonstrated that initial divergence was between groups occurring east and west of the Mississippi River, but we found further structuring among disjunct regions. We also found evidence for secondary contact between eastern and western groups, particularly in the Georgia population. Conclusions: Small, isolated populations of Clematis fremontii have higher levels of genetic diversity than we expected, but habitat loss still poses a major threat. Current levels of genetic diversity could indicate an extinction lag. Restoration and population augmentation efforts are needed for this species to persist long-term. Additionally, our data supports the hypothesis that separation of eastern and western C. fremontii populations dates to relatively recent Pleistocene events. This could be a vicariance event, such as meltwater mega-flooding of the Mississippi River, or an eastward expansion from a more widespread western group during an interglacial period. Our data did not support the hypotheses of ancient vicariance via the formation of the Mississippi embayment or very recent expansion dating to the Hypsithermal Interval. We also found that C. fremontii accumulated genetic variation upon isolation in xeric limestone prairie habitats, similar to a rapid radiation.