caa a22 4500 467885516 CHVBK 20180406152733.0 cr unu---uuuuu 170328e20060401xx s 000 0 eng 10.1007/s10021-005-0124-4 doi (NATIONALLICENCE)springer-10.1007/s10021-005-0124-4 Increases in Desert Shrub Productivity under Elevated Carbon Dioxide Vary with Water Availability [Elektronische Daten] [David Housman, Elke Naumburg, Travis Huxman, Therese Charlet, Robert Nowak, Stanley Smith] Productivity of aridland plants is predicted to increase substantially with rising atmospheric carbon dioxide (CO2) concentrations due to enhancement in plant water-use efficiency (WUE). However, to date, there are few detailed analyses of how intact desert vegetation responds to elevated CO2. From 1998 to 2001, we examined aboveground production, photosynthesis, and water relations within three species exposed to ambient (around 38 Pa) or elevated (55 Pa) CO2 concentrations at the Nevada Desert Free-Air CO2 Enrichment (FACE) Facility in southern Nevada, USA. The functional types sampled—evergreen (Larrea tridentata), drought-deciduous (Ambrosia dumosa), and winter-deciduous shrubs (Krameria erecta)—represent potentially different responses to elevated CO2 in this ecosystem. We found elevated CO2 significantly increased aboveground production in all three species during an anomalously wet year (1998), with relative production ratios (elevated:ambient CO2) ranging from 1.59 (Krameria) to 2.31 (Larrea). In three below-average rainfall years (1999-2001), growth was much reduced in all species, with only Ambrosia in 2001 having significantly higher production under elevated CO2. Integrated photosynthesis (mol CO2 m−2 y−1) in the three species was 1.26-2.03-fold higher under elevated CO2 in the wet year (1998) and 1.32-1.43-fold higher after the third year of reduced rainfall (2001). Instantaneous WUE was also higher in shrubs grown under elevated CO2. The timing of peak canopy development did not change under elevated CO2; for example, there was no observed extension of leaf longevity into the dry season in the deciduous species. Similarly, seasonal patterns in CO2 assimilation did not change, except for Larrea. Therefore, phenological and physiological patterns that characterize Mojave Desert perennials—early-season lags in canopy development behind peak photosynthetic capacity, coupled with reductions in late-season photosynthetic capacity prior to reductions in leaf area—were not significantly affected by elevated CO2. Together, these findings suggest that elevated CO2 can enhance the productivity of Mojave Desert shrubs, but this effect is most pronounced during years with abundant rainfall when soil resources are most available. Springer Science+Business Media, Inc., 2006 Ambrosia dumosa nationallicence desert productivity nationallicence elevated carbon dioxide nationallicence Krameria erecta nationallicence Larrea tridentata nationallicence Mojave Desert nationallicence photosynthesis nationallicence water-use efficiency nationallicence Housman David Department of Biological Sciences, University of Nevada Las Vegas, 89154-4004, Nevada, USA aut Naumburg Elke Department of Biological Sciences, University of Nevada Las Vegas, 89154-4004, Nevada, USA aut Huxman Travis Department of Ecology and Evolutionary Biology, University of Arizona, 85721, Tucson, Arizona, USA aut Charlet Therese Department of Biological Sciences, University of Nevada Las Vegas, 89154-4004, Nevada, USA aut Nowak Robert Department of Environmental and Resource Sciences, University of Nevada, 89557, Reno, Nevada, USA aut Smith Stanley Department of Biological Sciences, University of Nevada Las Vegas, 89154-4004, Nevada, USA aut Ecosystems Springer-Verlag; www.springer-ny.com 9/3(2006-04-01), 374-385 1432-9840 9:3<374 2006 9 10021 https://doi.org/10.1007/s10021-005-0124-4 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s10021-005-0124-4 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Housman David Department of Biological Sciences, University of Nevada Las Vegas, 89154-4004, Nevada, USA aut NATIONALLICENCE 700 1- Naumburg Elke Department of Biological Sciences, University of Nevada Las Vegas, 89154-4004, Nevada, USA aut NATIONALLICENCE 700 1- Huxman Travis Department of Ecology and Evolutionary Biology, University of Arizona, 85721, Tucson, Arizona, USA aut NATIONALLICENCE 700 1- Charlet Therese Department of Biological Sciences, University of Nevada Las Vegas, 89154-4004, Nevada, USA aut NATIONALLICENCE 700 1- Nowak Robert Department of Environmental and Resource Sciences, University of Nevada, 89557, Reno, Nevada, USA aut NATIONALLICENCE 700 1- Smith Stanley Department of Biological Sciences, University of Nevada Las Vegas, 89154-4004, Nevada, USA aut NATIONALLICENCE 773 0- Ecosystems Springer-Verlag; www.springer-ny.com 9/3(2006-04-01), 374-385 1432-9840 9:3<374 2006 9 10021 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer