Influence of late Quaternary climate change on present patterns of genetic variation in valley oak, Quercus lobata Née

• Published in: Molecular ecology Vol. 22; no. 13; pp. 3598 - 3612
• Main Authors: Gugger, Paul F, Ikegami, Makihiko, Sork, Victoria L
• Format: Journal Article
• Language: English
• Published: Oxford Blackwell Scientific Publications 01.07.2013; Blackwell Publishing Ltd; Blackwell
• Subjects: Bayes Theorem; Biological and medical sciences; Biological evolution; California; chloroplasts; Climate; Climate Change; Climatology. Bioclimatology. Climate change; coasts; correlation; DNA, Plant - genetics; Earth, ocean, space; ecological niche modelling; Ecosystem; Exact sciences and technology; External geophysics; flowering; Fundamental and applied biological sciences. Psychology; Gene Flow; Genetic diversity; genetic variance; Genetic Variation; Genetics of eukaryotes. Biological and molecular evolution; Haplotypes; hills; intraspecific variation; Meteorology; Microsatellite Repeats; Models, Biological; Models, Genetic; Molecular Sequence Data; mountains; niches; Paleoclimate science; phenology; Phylogenetics; Phylogeography; Plant ecology; Plant populations; Pleistocene; Population Dynamics; Population genetics, reproduction patterns; quantitative analysis; Quercus; Quercus - genetics; Quercus alba; Quercus lobata; redundancy analysis; Sequence Analysis, DNA; variance; California; USA, Coast Range; redundancy analysis; Genetic variability; Quaternary; Redundancy; Biological evolution; Phylogeography; Genetic diversity; Woody plant; Fagaceae; Modeling; Dynamical climatology; Climate change; ecological niche modelling; Quercus; Valley; Dicotyledones; Analysis; Angiospermae; Ecological niche; Spermatophyta; Pleistocene
• ISSN: 0962-1083; 1365-294X
• DOI: 10.1111/mec.12317

Phylogeography and ecological niche models (ENMs) suggest that late Quaternary glacial cycles have played a prominent role in shaping present population genetic structure and diversity, but have not applied quantitative methods to dissect the relative contribution of past and present climate vs. other forces. We integrate multilocus phylogeography, climate‐based ENMs and multivariate statistical approaches to infer the effects of late Quaternary climate change on contemporary genetic variation of valley oak (Quercus lobata Née). ENMs indicated that valley oak maintained a stable distribution with local migration from the last interglacial period (~120 ka) to the Last Glacial Maximum (~21 ka, LGM) to the present compared with large‐scale range shifts for an eastern North American white oak (Quercus alba L.). Coast Range and Sierra Nevada foothill populations diverged in the late Pleistocene before the LGM [104 ka (28–1622)] and have occupied somewhat distinct climate niches, according to ENMs and coalescent analyses of divergence time. In accordance with neutral expectations for stable populations, nuclear microsatellite diversity positively correlated with niche stability from the LGM to present. Most strikingly, nuclear and chloroplast microsatellite variation significantly correlated with LGM climate, even after controlling for associations with geographic location and present climate using partial redundancy analyses. Variance partitioning showed that LGM climate uniquely explains a similar proportion of genetic variance as present climate (16% vs. 11–18%), and together, past and present climate explains more than geography (19%). Climate can influence local expansion–contraction dynamics, flowering phenology and thus gene flow, and/or impose selective pressures. These results highlight the lingering effect of past climate on genetic variation in species with stable distributions.