Data product for "Nitrogen level and legume presence affect competitive interactions between a native and invasive grass"

We conducted a greenhouse experiment to investigate effects of the native N2-fixing legume, L. argenteus, on competitive interactions between seedlings of the non-native annual grass, B.tectorum, and a native perennial grass, E. multisetus, over a gradient of nitrogen (N) availability. The experiment consisted of three levels of N (0, 5mM and 20mM N, where mM = millimolar = millimoles per liter), two levels of target species (Bromus or Elymus) and three levels of competitor (Lupinus, Bromus, or Elymus).Within each treatment we measured tiller production, aboveground biomass, and tissue carbon (C) and N of target species. Potassium chloride (KCl) extractable soil N also was measured within each treatment.
Increased resource availability often promotes expansion of invasive species by changing competitive interactions. N2-fixing species are often abundant in nitrogen (N) poor systems, and have the capacity to alter resource availability, particularly N, and, thus, to indirectly influence competitive interactions. Like many arid areas dominated by perennial grasses, the sagebrush steppe of the western U.S. is threatened by invasion of non-native species, especially annual grasses. N2-fixing legumes are common, and are often used in restoration, but have the potential to facilitate invasion and expansion of invasive annual grasses. The presence of Lupinus was facilitative for Bromus but indirectly inhibitory for Elymus. Our results indicate that modification of the local resource pool by Lupinus can alter competitive outcomes among this native and non-native species and can provide an avenue for expansion of non-native B. tectorum.
Original metadata date was 05/14/2009. Metadata modified on 03/19/2013 to adjust citation to include the addition of a DOI (digital object identifier) and other minor edits. Minor metadata updates on 12/20/2016.