Population-level variation of Fraxinus americana (white ash) is influenced by precipitation differences across the native range
Renée M. Marchin (1), Emma L. Sage (1) and Joy K. Ward (1, 2)
1. Department of Ecology and Evolutionary Biology, University of Kansas, Lawrence, KS 66045, USA / 2. Corresponding author () / Received February 5, 2007; accepted May 1, 2007; published online October 15, 2007
Summary
We investigated the potential of Fraxinus americana L. to adapt to climate change by comparing diameter growth, survival and physiological status of 44 populations of 30-year-old
trees originating from throughout the species range and grown in a common garden. Populations originating closest to the latitude
of the common garden had the most rapid diameter growth and the highest survival. Among populations originating within a narrow
latitudinal band along an east–west gradient of decreasing precipitation, those from the drier western end were best adapted
to the dry climate of the common garden site, as judged by survival, stem circumference, leaf and wood carbon isotope ratios,
leaf mass per area and leaf nitrogen concentration. These findings suggest that eastern populations may not perform well under
the hotter and drier conditions predicted by climate change scenarios. Moreover, in the event of significant climate change,
the short-term acclimation responses (within a generation) of F. americana may be insufficient to ensure the continued vigor or survival of this species throughout much of its present range.
Keywords:
carbon isotope ratios, climate change, common garden, fitness, global change, intraspecific variation, photosynthesis, physiological
adaptation, stem circumference, stomatal conductance, temperate trees, tree rings, water stress.
