National Parks are hallmarks of ecosystem preservation in the United States. The introduction of alien invasive plant species threatens protection of these areas. Bromus tectorum L. (commonly called downy brome or cheatgrass), which is found in Rocky Mountain National Park (hereafter, the Park), Colorado, USA, has been implicated in early spring competition with native grasses, decreased soil n...

Two species of Psilochalcis (Hymenoptera: Chalcididae) wasps occurring in the Great Basin region western United States were sampled from three locations central Utah (USA) over a two-year period using Malaise traps. Each location is composed four contiguous habitat types: pinyon/juniper (Pinus edulis or P. monophylla and Juniperus osteosperma), sagebrush (Artemisia tridentata), cheatgrass (Brom...

Artemisia tridentata ssp. wyomingensis (Beetle & A. Young) S.L. Welsh-bunchgrass communities were used to analyze the influence of disturbances on invasibility after a recovery period. These communities evolved with periodic fires shifting dominance from shrubs to herbaceous species. However, fire can facilitate Bromus tectorum L. invasion of these plant communities. We evaluated the invasibili...

How plant populations, communities, and ecosystems respond to climate change is a critical focus in ecology today. The responses of introduced species may be especially rapid. Current models that incorporate temperature and precipitation suggest that future Bromus tectorum invasion risk is low for the Colorado Plateau. With a field warming experiment at two sites in southeastern Utah, we tested...

Comparisons of vegetation dynamics of riparian plant communities under livestock use and esclusions over a 10 year period were quantified in a Northeastern Oregon riparian zone. We measured species frequency, richness, diversity, evenness, and livestock utilization in 8 plant communities. Livestock grazed the study area from late August until mid September at a rate of 1.3 to 1.8 ha/AUM. Utiliz...

Allen P.S., Meyer S.E., Beckstead J. (2013): A predictive model for soil seed bank outcomes in the Pyrenophora semeniperda–Bromus tectorum pathosystem. Plant Protect. Sci., 49 (Special Issue): S21–S24. Pyrenophora semeniperda is abundant in soil seed banks of Bromus tectorum, where it kills a fraction of seeds throughout the year. The pathogen engages in a race with host seeds for endosperm res...

Two new phytotoxic sesquiterpenoid acids, named pyrenophoric acids B and C, were isolated together with the related pyrenophoric and abscisic acids from solid Bromus tectorum (cheatgrass) seed culture of the seed pathogen Pyrenophora semeniperda. This fungus has been proposed as a mycoherbicide for biocontrol of cheatgrass (Bromus tectorum), a Eurasian annual grass that has become invasive in r...

The present study aimed to investigate the effect of two type of soil (clay and sandy soils) in the potential allelopathic effects of Artemisia herba-alba, Oudneya africana crude powder (0, 1, 3 and 6%) on some growth parameters of two weeds (Bromus tectorum and Melilotus indica) under laboratory conditions (pot experiment). The experimental findings have reported that the donor species crude p...