Spatial Variation in Germination of Two Annual Brome Species in the Northern Great Plains

Downy brome or cheat grass (Bromus tectorum L.) and field brome (B. arvensis L.; Synonym = Bromus japonicus Thunb. ex Murr.; Japanese brome) are two annual exotic species that have increased the intensity and frequency of fire cycles in the Intermountain West of the United States, with millions of dollars in associated costs (DiTomaso 2000). These invasive brome species have a different impact in the Northern Great Plains of North America where they commonly co-occur in disturbed sites (White and Currie 1983, Haferkamp et al. 1993). In these mixed-grass prairie rangelands, annual bromes compete against other forage species (Haferkamp et al. 1997) and reduce litter decomposition rates (Ogle et al. 2003), which negatively impacts ecosystem services of biomass production and soil nutrient availability. In central plains croplands, downy brome invades alfalfa fields (Kapusta and Strieker 1975), wheat fields (Wicks 1984, Ostlie and Howatt 2013), and perennial grass pastures and seed production areas (Wicks 1984). Downy brome is a regulated plant in Montana (Montana Noxious Weed List, December 2013) and has been found in all counties of Montana since 1950 (Menalled et al. 2008). Field brome is found in all North American states and provinces (USDA Plants Database http://plants.usda.gov). It is used as a winter cover crop in vegetable plots and orchards in the Northeastern United States (NRCS 2006). Field brome has no formal designation in the state of Montana, although downy brome and field brome are commonly grouped together and are referred to colloquially as “cheatgrass” in the state

Managing Invasive Plants on Great Plains Grasslands: A Discussion of Current Challenges

The Great Plains of North America encompass approximately 1,300,000 km2 of land from Texas to Saskatchewan. The integrity of these lands is under continual assault by long-established and newly-arrived invasive plant species, which can threaten native species and diminish land values and ecological goods and services by degrading desired grassland resources. The Great Plains are a mixture of privately and publicly owned lands, which leads to a patchwork of varying management goals and strategies for controlling invasive plants. Continually updated knowledge is required for efficient and effective management of threats posed by changing environments and invasive plants. Here we discuss current challenges, contemporary management strategies, and management tools and their integration, in hopes of presenting a knowledge resource for new and experienced land managers and others involved in making decisions regarding invasive plant management in the Great Plains

Managing Invasive Plants on Great Plains Grasslands: A Discussion of Current Challenges

The Great Plains of North America encompass approximately 1,300,000 km2 of land from Texas to Saskatchewan. The integrity of these lands is under continual assault by long-established and newly-arrived invasive plant species, which can threaten native species and diminish land values and ecological goods and services by degrading desired grassland resources. The Great Plains are a mixture of privately and publicly owned lands, which leads to a patchwork of varying management goals and strategies for controlling invasive plants. Continually updated knowledge is required for efficient and effective management of threats posed by changing environments and invasive plants. Here we discuss current challenges, contemporary management strategies, and management tools and their integration, in hopes of presenting a knowledge resource for new and experienced land managers and others involved in making decisions regarding invasive plant management in the Great Plains

The high-resolution map of Oxia Planum, Mars; the landing site of the ExoMars Rosalind Franklin rover mission

This 1:30,000 scale geological map describes Oxia Planum, Mars, the landing site for the ExoMars Rosalind Franklin rover mission. The map represents our current understanding of bedrock units and their relationships prior to Rosalind Franklin’s exploration of this location. The map details 15 bedrock units organised into 6 groups and 7 textural and surficial units. The bedrock units were identified using visible and near-infrared remote sensing datasets. The objectives of this map are (i) to identify where the most astrobiologically relevant rocks are likely to be found, (ii) to show where hypotheses about their geological context (within Oxia Planum and in the wider geological history of Mars) can be tested, (iii) to inform both the long-term (hundreds of metres to ∼1 km) and the short-term (tens of metres) activity planning for rover exploration, and (iv) to allow the samples analysed by the rover to be interpreted within their regional geological context

Spatial Variation in Germination of Two Annual Brome Species in the Northern Great Plains

Downy brome or cheat grass (Bromus tectorum L.) and field brome (B. arvensis L.; Synonym = Bromus japonicus Thunb. ex Murr.; Japanese brome) are two annual exotic species that have increased the intensity and frequency of fire cycles in the Intermountain West of the United States, with millions of dollars in associated costs (DiTomaso 2000). These invasive brome species have a different impact in the Northern Great Plains of North America where they commonly co-occur in disturbed sites (White and Currie 1983, Haferkamp et al. 1993). In these mixed-grass prairie rangelands, annual bromes compete against other forage species (Haferkamp et al. 1997) and reduce litter decomposition rates (Ogle et al. 2003), which negatively impacts ecosystem services of biomass production and soil nutrient availability. In central plains croplands, downy brome invades alfalfa fields (Kapusta and Strieker 1975), wheat fields (Wicks 1984, Ostlie and Howatt 2013), and perennial grass pastures and seed production areas (Wicks 1984). Downy brome is a regulated plant in Montana (Montana Noxious Weed List, December 2013) and has been found in all counties of Montana since 1950 (Menalled et al. 2008). Field brome is found in all North American states and provinces (USDA Plants Database http://plants.usda.gov). It is used as a winter cover crop in vegetable plots and orchards in the Northeastern United States (NRCS 2006). Field brome has no formal designation in the state of Montana, although downy brome and field brome are commonly grouped together and are referred to colloquially as “cheatgrass” in the state

Seeding, Herbicide, and Fungicide Impact on Perennial Grass Establishment in Cheatgrass Infested Habitats

The article discusses research which examined the impact of seeding, herbicide and fungicide on Bromus tectorum, a perennial grass. Topics discussed include factors contributing to Bromus tectorum invasion into rangelands, reasons for failure of revegetation of native species, integration of herbecide imazapic with generalist grass pathogen Pyrenophora semeniperda and common causes of revegetation failure addressed by integrating multiple management strategies

Temperature effects on three downy brome \u3cem\u3e(Bromus tectorum)\u3c/em\u3e seed collections inoculated with the fungal pathogen \u3cem\u3ePyrenophora semeniperda\u3c/em\u3e

Downy brome (Bromus tectorum L., syn. cheatgrass) is a winter annual grass that invades North American cropping, forage, and rangeland systems. Control is often difficult to achieve, because B. tectorum has a large seedbank, which results in continuous propagule pressure. Pyrenophora semeniperda (Brittlebank and Adam) Shoemaker, a soilborne fungal pathogen, has been investigated as a biological control for B. tectorum, because it can kill seeds that remain in the seedbank, thereby reducing propagule pressure. Temperature influences P. semeniperda and has not been investigated in the context of seeds collected from different B. tectorum locations, that may vary in susceptibility to infection. We compared the effects of temperature (13, 17, 21, 25 C) and B. tectorum seed locations (range, crop, subalpine) with different mean seed weights on infection rates of P. semeniperda using a temperature-gradient table. Infection differed by seed location (P \u3c 0.001) and temperature (P \u3c 0.001), with lighter-weight seeds (i.e., range and subalpine) more susceptible to P. semeniperda infection. Infection increased as temperature increased and was higher at 21 C (66.7 ± 6.7%) and 25 C (73.3 ± 6.0%). Germination was affected by seed location (P \u3c 0.001) and temperature (P = 0.019). Germination was highest for the crop seed location (45.4 ± 4.2%) and overall decreased at higher temperatures (21 and 25 C). Our results suggest that B. tectorum seeds from a crop location are less affected by P. semeniperda than those from range and subalpine locations. Moreover, this demonstrates a temperature-dependent effect on all populations