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Marked genetic divergence among sky island populations of Sedum lanceolatum (Crassulaceae) in the Rocky Mountains
Author(s) -
DeChaine Eric G.,
Martin Andrew P.
Publication year - 2005
Publication title -
american journal of botany
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.218
H-Index - 151
eISSN - 1537-2197
pISSN - 0002-9122
DOI - 10.3732/ajb.92.3.477
Subject(s) - biology , ecology , refugium (fishkeeping) , biological dispersal , range (aeronautics) , glacial period , alpine plant , phylogeography , phylogenetics , population , habitat , paleontology , materials science , demography , biochemistry , gene , sociology , composite material
Climate change during the Quaternary played an important role in the differentiation and evolution of plants. A prevailing hypothesis is that alpine and arctic species survived glacial periods in refugia at the periphery of glaciers. Though the Rocky Mountains, south of the southernmost extent of continental ice, served as an important glacial refuge, little is known about how climate cycles influenced populations within this region. We inferred the phylogeography of Sedum lanceolatum (Crassulaceae) within the Rocky Mountain refugium to assess how this high‐elevation plant responded to glacial cycles. We sequenced 884 base pairs (bp) of cpDNA intergenic spacers (tRNA‐L to tRNA‐F and tRNA‐S to tRNA‐G) for 333 individuals from 18 alpine populations. Our highly variable markers allowed us to infer that populations persisted across the latitudinal range throughout the climate cycles, exhibited significant genetic structure, and experienced cycles of range expansion and fragmentation. Genetic differentiation in S. lanceolatum was most likely a product of short‐distance elevational migration in response to climate change, low seed dispersal, and vegetative reproduction. To the extent that Sedum is a good model system, paleoclimatic cycles were probably a major factor preserving genetic variation and promoting divergence in high‐elevation flora of the Rocky Mountains.