| Autor: |
Johnson LC; Biology, Kansas State University Manhattan, KS, USA., Olsen JT; Department of Biological Sciences, Fort Hays State University Hays, KS, USA., Tetreault H; Biology, Kansas State University Manhattan, KS, USA., DeLaCruz A; Biology, Kansas State University Manhattan, KS, USA., Bryant J; Biology, Kansas State University Manhattan, KS, USA., Morgan TJ; Biology, Kansas State University Manhattan, KS, USA., Knapp M; Department of Agronomy, Kansas State University Manhattan, KS, USA., Bello NM; Statistics, Kansas State University Manhattan, KS, USA., Baer SG; Plant Biology and Center for Ecology, Southern Illinois University Carbondale, IL, USA., Maricle BR; Department of Biological Sciences, Fort Hays State University Hays, KS, USA. |
| Abstrakt: |
Identifying suitable genetic stock for restoration often employs a 'best guess' approach. Without adaptive variation studies, restoration may be misguided. We test the extent to which climate in central US grasslands exerts selection pressure on a foundation grass big bluestem (Andropogon gerardii), widely used in restorations, and resulting in local adaptation. We seeded three regional ecotypes of A. gerardii in reciprocal transplant garden communities across 1150 km precipitation gradient. We measured ecological responses over several timescales (instantaneous gas exchange, medium-term chlorophyll absorbance, and long-term responses of establishment and cover) in response to climate and biotic factors and tested if ecotypes could expand range. The ecotype from the driest region exhibited greatest cover under low rainfall, suggesting local adaptation under abiotic stress. Unexpectedly, no evidence for cover differences between ecotypes exists at mesic sites where establishment and cover of all ecotypes were low, perhaps due to strong biotic pressures. Expression of adaptive differences is strongly environment specific. Given observed adaptive variation, the most conservative restoration strategy would be to plant the local ecotype, especially in drier locations. With superior performance of the most xeric ecotype under dry conditions and predicted drought, this ecotype may migrate eastward, naturally or with assistance in restorations. |
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