Paleoecological evidence indicates that Pleistocene glaciations caused broad scale changes in vegetation across North America, but how individual plant species responded to these repeated cycles of glaciation remains largely unstudied. This project will examine how the widespread, North American, Solidago simplex species complex responded to the most recent period of glaciation. Analyses of chloroplast DNA sequence data will be used to 1) describe and assess the structuring of genetic diversity across the range of S. simplex in North America and 2) test the long-standing hypothesis that some widespread species survived glaciation in western North American refugia and migrated to eastern, glaciated regions of the continent more recently during the Holocene.
This study will be one of the first molecular phylogeographic studies to examine the biogeographic patterns and glacial history of an herbaceous plant species across the entirety of its North American range. The information generated by this work will provide us with more refined understandings of 1) how plant species responded to historical climate change and 2) how Pleistocene glacial cycles affected population differentiation and speciation. This information can provide valuable insight into how extant species may respond to future climate change and can therefore significantly aid current habitat and species conservation efforts.
