Invasive Species
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This study compared unburned and burned sites to determine how cheatgrass and native wheatgrass abundance and distribution varied. Wheatgrass density increased in high-nutrient areas. Soil cores from burned microsites were also transplanted to a controlled area and seeded with either wheatgrass or cheatgrass to determine microsite effects on plant establishment and growth. There were differences in microsite soil properties, which were not affected by plant growth, and differences in growth but not establishment of grass seeds. Microsites are likely important for post-fire resistance of rangeland to cheatgrass establishment.
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This paper provides an overview of recent and ongoing invasive species research conducted by Rocky Mountain Research Station scientists in the Intermountain West in order to familiarize managers with the Station
and its products.
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This synthesis investigates the resistance and resilience differences among the cold and hot desert shrublands of North America. Differences are largely determined by spatial and temporal patterns of productivity but also are affected by ecological memory, severity and frequency of disturbance, and feedbacks among invasive species and disturbance regimes. Strategies for preventing or managing invasive plant/fire regimes cycles in desert shrublands include: 1) conducting periodic resource assessments to evaluate the probability of establishment of an altered fire regime; 2) understanding ecological thresholds associated within invasion resistance and fire resilience that characterize transitions from desirable to undesirable fire regimes; and 3) prioritizing management activities based on resistance of areas to invasion and resilience to fire.
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This research brief discusses the effects of fire and invasive species on biological, chemical, and physical properties of desert soils. Although soil may recover from the impacts of fire during succession, these changes are permanent under persistent invasive species. The most severe effects of fire occur under high temperatures with high fuel buildup and soil moisture that conducts heat downward.
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This study compared mechanical and chemical treatments to control crested wheatgrass and found that effective control can require secondary treatments to reduce the seed bank and open stands to dominance by seeded native species. Manipulation of crested wheatgrass stands to restore native species carries the risk of weed invasion if secondary treatments effectively control the wheatgrass and native species have limited survival due to drought.
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The objective of this study was to determine the feasibility of restoring native plant species to crested wheatgrass-dominated rangeland by testing five suppression treatments. Results suggested that suppression treatments were not effective and therefore did not improve restoration of native species in crested wheatgrass stands. Native species establishment may require subsequent management to favor persistence of native species and retard crested wheatgrass.
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Results of this study indicate that native grasses more readily establish in synchrony with crested wheatgrass than native shrubs, but once established, native shrubs are more likely to coexist and persist with crested wheatgrass because of high niche differentiation (e.g., not limited by the same resource). Results also suggest that developing strategies to minimize interference from crested wheatgrass seedlings emerging from seed banks will enhance the establishment of native species seeded into crested wheatgrass–dominated communities.
View field guide.
This field guide is designed to help agricultural producers, land managers, homeowners, recreationists, and others to identify the noxious weeds of Nevada. All weeds listed by Nevada state law (as of 2010) are included, each with a brief description, color photographs, and recommendations for control.
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This field guide is designed to help identify some of the common noxious and invasive weed species that are currently threatening Utah and have been identified on Utah’s state weed list.
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This study investigated downy brome and seeded species responses to variable rates of imazapic in two plant communities (salt desert shrub and Wyoming big sagebrush). Overall, imazapic was useful for helping establish desirable perennial species, but unless downy brome is reduced below a critical threshold, favorable precipitation can return sites to pretreatment levels within two years.