Implications of Ecotypic Variation for the Response of Tundra Plants to Climate Change

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"This award is funded under the American Recovery and Reinvestment Act of 2009(Public Law 111-5)."This project will examine the role of ecotypic differentiation, i.e., local adaptation of plants to the environment, in modulating and potentially limiting the response of a plant species to climate change. Two reciprocal transplant experiments were set up in northern Alaska in 1979-80 to examine ecotypic differentiation; one with Eriophorum vaginatum arrayed along a latitudinal gradient, and one with Dryas octopetala arrayed along an elevational gradient. Both experiments demonstrated strong between-population genetic differentiation in these two arctic plant species. In the proposed study, the PIs will re-census the two reciprocal transplant studies to ask whether climate change has already resulted in a ?mismatch? between ecotypes and their original environment, signaling an ?adaptational lag? in response to climate change. A suite of performance (fitness-related) measures will be made in each of the transplant sites (3 sites x 3 populations for D. octopetala, and 6 sites x 6 populations for E. vaginatum), including survival, growth, and reproduction. Growth will be measured using size-classified matrix modeling of shoot populations for both species. Relevant physiological parameters will also be measured, including photosynthesis, carbon isotope ratios, and tissue nitrogen content, in order to explain performance differences among populations and sites. The data will be analyzed with multi-way ANOVAs or loglikelihood analyses, with repeated measures, as appropriate. Data will be archived through the Toolik LTER database.