Small-scale adaptation to geothermal soil heating in a perennial herb revealed by combining crosses and transplantations.
Valdés A, Helmutsdóttir VF, Marteinsdóttir B, Ehrlén J
Climate Adaptation
That patch of wildflowers at the edge of a sun-baked driveway or south-facing slope may already be genetically distinct from the same species growing ten feet away in the shade — and transplanting them could set both populations back.
Scientists studied a common white-flowered herb called mouse-ear chickweed growing near geothermal areas where the ground temperature varies dramatically within a small area. They raised plants from parents living across this temperature range and transplanted their offspring back into different temperature zones, then watched how well they grew and flowered over two years. What they found is that plants from cold ground had real trouble surviving in warm ground, but plants from warm ground did just fine in cold ground — meaning evolution shaped these plants differently depending on how harsh their birthplace was.
Key Findings
Survival, flowering, and overall fitness all declined in warmer soils, showing heat is the harder environmental challenge in this system.
Adaptation was asymmetric: cold-origin plants performed poorly in warm soils, but warm-origin plants survived well in cold soils, suggesting directional selection pressure from heat stress.
Flowering time tracked both soil temperature and the mismatch between a plant's origin and planting site, indicating phenology is a key mechanism linking local adaptation to thermal environment.
chevron_right Technical Summary
A small flowering plant growing near geothermal hot spots in Iceland has evolved distinct adaptations to local soil temperatures — sometimes across just a few meters. Plants from cooler soils struggled in warmer spots, but warm-origin plants did fine everywhere cool, revealing that adaptation to heat is harder to reverse than adaptation to cold.
Abstract Preview
Identifying environmental factors associated with local adaptation and traits under selection is key to linking evolutionary processes to the environment. While reciprocal transplantation studies a...
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Cerastium is a genus of annual, winter annual, or perennial flowering plants belonging to the family Caryophyllaceae. They are commonly called mouse-ears or mouse-ear chickweeds. There are 214 accepted species, found nearly worldwide but with the greatest concentration in the northern temperate r...