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Invasive annual cheatgrass (Bromus tectorum L.) and medusahead wildrye [Taeniatherum caput-medusae (L.) Nevski ssp. asperum (Simonk.) Melderis] have decreased livestock productivity and biological diversity and increased the frequency of wildfire on rangelands in the western United States. On disturbed sites, squirreltail (Elymus sp.), a short-lived North American perennial, appears to compete against invasive exotic annuals when available soil N and nitrification are reduced. We tested the hypothesis that differences in N uptake activity could account for this phenomenon. North American seedlings of perennial bluebunch wheatgrass [Pseudoroegneria spicata (Pursh) �. Löve], four populations of squirreltail, and...
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The mechanisms responsible for soil-N-mediated species replacement of native perennial grasses by the invasive annual grasses cheatgrass (Bromus tectorum L.) and medusahead (Taeniatherum caput-medusae [L.] Nevski) on rangelands are not completely understood. In addition, the contributions of distinct forms of inorganic N (i.e., NH4+ and NO3-) to these shifts in species composition are currently unclear. Consequently, we conducted a greenhouse experiment to test 2 hypotheses: 1) that low N availability reduces growth (root and shoot) and N allocation of invasive annual seedlings more than native perennial species, and 2) that seedling growth and N allocation of invasive annual grasses is more responsive than native...
Categories: Publication;
Types: Citation,
Journal Citation;
Tags: Allen Press and Society for Range Management,
Journal of Range Management,
carbon-to-nitrogen ration (C:N),
invasive annual grass,
native perennial grass, All tags...
nitrogen availability,
nitrogen form,
root development,
seedling development, Fewer tags
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