The historical context of contemporary climatic adaptation: A case study in the climatically dynamic and environmentally complex southwestern United States

Robert Massatti; L. Lacey Knowles

doi:10.1111/ecog.04840

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The historical context of contemporary climatic adaptation: A case study in the climatically dynamic and environmentally complex southwestern United States

Robert Massatti·L. Lacey Knowles

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Abstract

The process of adaptation can be highly dependent upon historical and contemporary factors, especially in environmentally and topographically complex regions affected by Pleistocene glaciations. Here, we investigate Hilaria jamesii (Poaceae), a dryland C 4 graminoid, to test how patterns of adaptive genetic variation are linked to its glacial and post‐glacial history. We show that the species persisted in a single, southern refugium during the last glacial period and subsequently migrated throughout its current distribution concurrent with post‐glacial warming. The species’ putative adaptive genetic variation correlates with climatic gradients (e.g. monsoon precipitation and mean diurnal temperature range) that covary with the species’ probable route of demographic expansion. The short timescale and multiple climatic dimensions of adaptation imply that natural selection acted primarily upon standing genetic variation. These findings suggest that restoration and conservation practices should prioritize the maintenance of standing genetic variation to ensure that species have the capacity to respond to future environmental changes.

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Source-reported bounding extent: 31.052933985705163° to 42.65012181368022° latitude; -120.89355468749999° to -101.77734374999999° longitude. This indicates report coverage, not an exact sampling location. View area on OpenStreetMap.

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Robert Massatti, L. Lacey Knowles. 2020-01-23. The historical context of contemporary climatic adaptation: A case study in the climatically dynamic and environmentally complex southwestern United States. https://doi.org/10.1111/ecog.04840

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