Meeting Abstract
Flora endemic to the cold habitats of the Northern Hemisphere, i.e., mountains and Arctic, provide important models for investigating diversification and disjunctions, given both the intense climatic fluctuations that have occurred during the Quaternary and the fascinating biogeographic patterns found in these regions. Micranthes (Saxifragaceae), a clade of small-flowered herbs comprising 80 species, is an ideal group for investigating the evolution and diversification of plants in montane and Arctic ecosystems, which are especially vulnerable to climate change. Over one-third of all species of Micranthes are cold-adapted—in comparison to only four percent of all known vascular plant species—suggesting that this group is specialized for these conditions. This assumption is further supported by the fact that many of the cold-adapted Micranthes have a suite of specialized morphological and reproductive traits not seen in low-elevation and low-latitude species of this clade, including leaf succulence, strongly asymmetric corollas, and asexual reproduction through bulbils. This research explores the evolution and geographic spread of cold-adapted plants through both phylogenomics using Micranthes as a model. This goal was accomplished by reconstructing a time-calibrated phylogeny based on hundreds of low-copy nuclear markers, and in conjunction with a phylogeny reconstructed from the majority of the plastome. These genes were analyzed in multiple downstream analyses to elucidate the patterns of diversification in this group. Together, these investigations provide insights into speciation and biodiversity at multiple spatial and phylogenetic scales.
