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Influence of late Q uaternary climate change on present patterns of genetic variation in valley oak, Q uercus lobata Née
Author(s) -
Gugger Paul F.,
Ikegami Makihiko,
Sork Victoria L.
Publication year - 2013
Publication title -
molecular ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.619
H-Index - 225
eISSN - 1365-294X
pISSN - 0962-1083
DOI - 10.1111/mec.12317
Subject(s) - biology , phylogeography , last glacial maximum , ecology , coalescent theory , genetic diversity , climate change , ecological niche , range (aeronautics) , population , niche , genetic variation , glacial period , demography , phylogenetics , paleontology , biochemistry , materials science , composite material , sociology , habitat , gene
Phylogeography and ecological niche models ( ENM s) suggest that late Q uaternary 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 ENM s and multivariate statistical approaches to infer the effects of late Quaternary climate change on contemporary genetic variation of valley oak ( Q uercus lobata Née). ENM s indicated that valley oak maintained a stable distribution with local migration from the last interglacial period (~120 ka) to the L ast G lacial M aximum (~21 ka, LGM ) to the present compared with large‐scale range shifts for an eastern N orth A merican white oak ( Q uercus alba L.). Coast R ange and S ierra N evada foothill populations diverged in the late P leistocene before the LGM [104 ka (28–1622)] and have occupied somewhat distinct climate niches, according to ENM s 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.