caa a22 4500 463168178 CHVBK 20180406164805.0 cr unu---uuuuu 170326e20070401xx s 000 0 eng 10.1007/s10530-006-9033-5 doi (NATIONALLICENCE)springer-10.1007/s10530-006-9033-5 Variation in the establishment of a non-native annual grass influences competitive interactions with Mojave Desert perennials [Elektronische Daten] [Lesley DeFalco, George Fernandez, Robert Nowak] Competition between native and non-native species can change the composition and structure of plant communities, but in deserts, the highly variable timing of resource availability also influences non-native plant establishment, thus modulating their impacts on native species. In a field experiment, we varied densities of the non-native annual grass Bromus madritensis ssp. rubens around individuals of three native Mojave Desert perennials—Larrea tridentata, Achnatherum hymenoides, and Pleuraphis rigida—in either winter or spring. For comparison, additional plots were prepared for the same perennial species and seasons, but with a mixture of native annual species as neighbors. Growth of perennials declined when Bromus was established in winter because Bromus stands had 2-3months of growth and high water use before perennial growth began. However, water potentials for the perennials were not significantly reduced, suggesting that direct competition for water may not be the major mechanism driving reduced perennial growth. The impact of Bromus on Larrea was lower than for the two perennial grasses, likely because Larrea maintains low growth rates throughout the year, even after Bromus has completed its life cycle. This result contrasts with the perennial grasses, whose phenology completely overlaps with (Achnatherum) or closely follows (Pleuraphis) that of Bromus. In comparison, Bromus plants established in spring were smaller than those established in winter and thus did not effectively reduce growth of the perennials. Growth of perennials with mixed annuals as neighbors also did not differ from those with Bromus neighbors of equivalent biomass, but stands of these native annuals did not achieve the high biomass of Bromus stands that were necessary to reduce perennial growth. Seed dormancy and narrow requirements for seedling survivorship of native annuals produce densities and biomass lower than those achieved by Bromus; thus, impacts of native Mojave Desert annuals on perennials are expected to be lower than those of Bromus. Springer Science+Business Media B.V., 2006 Creosote bush nationallicence Galleta grass nationallicence Indian ricegrass nationallicence Invasive species nationallicence Plant competition nationallicence DeFalco Lesley US Geological Survey, Western Ecological Research Center, 160 N. Stephanie Street, 89074, Henderson, NV, USA aut Fernandez George Nevada Agricultural Experiment Station, University of Nevada, 89557, Reno, NV, USA aut Nowak Robert Program in Ecology, Evolution and Conservation Biology, Department of Natural Resources and Environmental Science, University of Nevada, 89557, Reno, NV, USA aut Biological Invasions Kluwer Academic Publishers 9/3(2007-04-01), 293-307 1387-3547 9:3<293 2007 9 10530 https://doi.org/10.1007/s10530-006-9033-5 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s10530-006-9033-5 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- DeFalco Lesley US Geological Survey, Western Ecological Research Center, 160 N. Stephanie Street, 89074, Henderson, NV, USA aut NATIONALLICENCE 700 1- Fernandez George Nevada Agricultural Experiment Station, University of Nevada, 89557, Reno, NV, USA aut NATIONALLICENCE 700 1- Nowak Robert Program in Ecology, Evolution and Conservation Biology, Department of Natural Resources and Environmental Science, University of Nevada, 89557, Reno, NV, USA aut NATIONALLICENCE 773 0- Biological Invasions Kluwer Academic Publishers 9/3(2007-04-01), 293-307 1387-3547 9:3<293 2007 9 10530 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer