Plant Ecology

, Volume 146, Issue 2, pp 195–204

Gas exchange and water relations of two Rocky Mountain shrub species exposed to a climate change manipulation

  • M. Rebecca Shaw
  • Michael E. Loik
  • John Harte

DOI: 10.1023/A:1009863201751

Cite this article as:
Shaw, M.R., Loik, M.E. & Harte, J. Plant Ecology (2000) 146: 195. doi:10.1023/A:1009863201751


Gas exchange and water relations responses to warming were compared for two shrub species, Artemisia tridentata spp. vaseyana (Asteraceae), a widely distributed evergreen species of the Great Basin and the western slope of the Rocky Mountains, and Pentaphylloides floribunda (Rosaceae), a deciduous shrub limited in distribution to moist, high-elevation meadows. Plants were exposed to an in situ infrared (IR) climate change manipulation at the Rocky Mountain Biological Laboratory, near Crested Butte, CO. Measurements of gas exchange and water relations were made on the two species in July and August, 1993 from plants growing in situ in infrared-heated and control plots. Carbon dioxide uptake, water loss, leaf temperature, water use efficiency, and water potential were compared to test the hypothesis that leaf and soil responses to IR will cause leaf level changes in photosynthesis. Photosynthetic CO2 uptake and water use efficiency increased for A. tridentata (2.9 vs. 1.9 μmol m−2 s−1 and 1.2 vs. 0.7 mmol C/mol H2O) in the heated plots compared to the controls, while water potential was significantly lower in the heated plots (−1.1 vs. −0.5 MPa). The heating treatment decreased rates of photosynthesis for P. floribunda, but not significantly so. For A. tridentata, the results are consistent with the community-level changes observed with heating. Taken together, the evidence suggests that global warming is likely to result in increasing dominance of A. tridentata in subalpine meadow habitat now dominated by forbs.

ArtemisiaClimate changePentaphylloidesPhotosynthesisRocky MountainsSubalpineTranspirationWater potentialWater use efficiency

Copyright information

© Kluwer Academic Publishers 2000

Authors and Affiliations

  • M. Rebecca Shaw
    • 1
  • Michael E. Loik
    • 2
  • John Harte
    • 3
  1. 1.Department of Plant BiologyCarnegie Institution of WashingtonStanfordUSA
  2. 2.Department of BiologyCalifornia State UniversitySan BernardinoUSA
  3. 3.Energy and Resources GroupUniversity of CaliforniaBerkeleyUSA