Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
5766579 | Environmental and Experimental Botany | 2017 | 8 Pages |
Abstract
The invasive grass Bromus tectorum fuels fires, displaces native species, and reduces wildlife habitat on sagebrush steppe throughout the western United States. Recently, it has spread from the Great Basin Desert into higher elevations of the eastern Sierra Nevada, where it coexists with natives but has not yet altered fire regimes. We evaluated effects of a springtime water pulse (+10Â mm) in a drought year on photosynthesis for B. tectorum and co-occurring shallow-rooted native perennials Achnatherum hymenoides, Elymus elymoides, and Lupinus argenteus near the range limit of B. tectorum at â¼2175Â m in California. Watered B. tectorum had the largest increase in stomatal conductance (27%) of the four species. Watering increased CO2 assimilation for B. tectorum by 78% over controls, compared to 17% for A. hymenoides, 2% for E. elymoides, and 29% for L. argenteus. Electron transport rate within Photosystem II increased for watered B. tectorum and A. hymenoides, but not for E. elymoides and L. argenteus. Instantaneous electron transport rate and carbon assimilation were more responsive for B. tectorum than natives following a spring water pulse during drought. Rapid upregulation of carbon uptake in spring in response to soil re-wetting during drought could facilitate B. tectorum spread at high elevation.
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Authors
Catherine E. Wade, Michael E. Loik,