Wednesday, August 13, 2014

Lagging adaptation to warming climate

See below for translation into non-technial language
http://www.pnas.org/content/111/22/7906.abstract?sid=67028a1a-1b8f-4779-86dc-1117d0822753

Proceedings of the Natural Academy of Sciences of the United States of America
Issue > vol. 111 no. 22 > Amity M. Wilczek, 7906–7913, doi: 10.1073/pnas.1406314111
Contributed by Johanna Schmitt, April 8, 2014 (sent for review June 14, 2013; reviewed by Steven J. Franks and Julie R. Etterson)

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If climate change outpaces the rate of adaptive evolution within a site, populations previously well adapted to local conditions may decline or disappear, and banked seeds from those populations will be unsuitable for restoring them. However, if such adaptational lag has occurred, immigrants from historically warmer climates will outperform natives and may provide genetic potential for evolutionary rescue. We tested for lagging adaptation to warming climate using banked seeds of the annual weed Arabidopsis thaliana [thale cress] in common garden experiments in four sites across the species’ native European range: Valencia, Spain; Norwich, United Kingdom; Halle, Germany; and Oulu, Finland. Genotypes originating from geographic regions near the planting site had high relative fitness in each site, direct evidence for broad-scale geographic adaptation in this model species. However, genotypes originating in sites historically warmer than the planting site had higher average relative fitness than local genotypes in every site, especially at the northern range limit in Finland. This result suggests that local adaptive optima have shifted rapidly with recent warming across the species’ native range.

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[More easily understood description of this research from New Scientist magazine May 24, 2014 page 8]

http://www.expertcore.org/viewtopic.php?f=13&t=4464

Amity Wilczek and Johanna Schmitt at Brown University in Providence, Rhode Island, examined thale cress seeds that had been banked on Earth for 70 years. They planted different varieties of the cress at sites in Spain, Germany, the UK and Finland, including versions that were native to each region 70 years ago.

At every site, they found that thale cress varieties originally from warmer climates grew better than plants grown from native seeds – reflecting changes in climate in the decades since they were collected (PNAS, doi.org/st7). "Seeds originally collected from a particular region may no longer be best suited to the climate of that region in the future," says Schmitt.

She adds that off-planet seed banks are an intriguing idea, although she thinks a climate-change cataclysm is much more likely to happen first. Either way seed banks should save a broad range of genetic diversity within a species to ensure success.

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