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

January 23, 2020

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 C4 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.

Citation Information

Publication Year 2020
Title The historical context of contemporary climatic adaptation: A case study in the climatically dynamic and environmentally complex southwestern United States
DOI 10.1111/ecog.04840
Authors Robert Massatti, L. Lacey Knowles
Publication Type Article
Publication Subtype Journal Article
Series Title Ecography
Index ID 70208027
Record Source USGS Publications Warehouse
USGS Organization Southwest Biological Science Center