Mountain Brome Research Articles

Soil moisture and competition determine soil biota effects on invasive Centaurea stoebe

Abstract Soil biota, such as root‐associating fungal mutualists and pathogens, influence plant–plant interactions. Yet, the context‐dependency of their effects remains poorly understood, hindering our ability to predict plant invasions. We targeted Centaurea stoebe, an invasive plant which is more successful in arid than mesic North American grasslands. We asked how the abundances of the arbuscular mycorrhizal (AM) fungi and potentially pathogenic fungi are moderated by soil moisture and if shifts in these guilds correspond with C. stoebe growth and competitiveness. We grew C. stoebe plants in pots with every combination of three treatments: soil moisture (wet, dry), soil biota (sterile, live) and competition (none, native grass Bromus marginatus). We measured plant responses and root colonization by AM fungi, identified the relative sequence abundance of AM and potentially pathogenic fungi via guild matches of ITS2 sequences in the database FUNGuild, and examined shifts in AM and potentially pathogenic fungal communities based on the SSU rRNA gene and ITS2, respectively. Soil biota reduced C. stoebe growth in wet but not dry soils, and the presence of the native competitor Bromus marginatus exacerbated these effects. This shift in responsiveness corresponded with relatively fewer AM and more potentially pathogenic fungi in C. stoebe roots grown in wet soils, and vice versa in dry soils. Furthermore, in dry soils, C. stoebe's AM fungal community was strongly dominated by Glomus spp. Conversely, B. marginatus response to soil biota was not affected by soil moisture, and shifts in relative abundance of potentially pathogenic and AM fungi were generally opposite to those observed in C. stoebe. These results suggest that soil biota effects on host plants are species‐specific and depend on soil moisture. Furthermore, native plants can promote pathogens in distantly related invasive neighbours, potentially generating biotic resistance. Thus, plant invasions may be mediated by interactions between soil biota, soil moisture, and identity of native competitor. Predicting invasions as the climate continues to change will require surveys and experiments across relevant landscape‐level gradients of invasion and environmental factors. Read the free Plain Language Summary for this article on the Journal blog.

Importance of considering soils in seed transfer zone development: evidence from a study of the native Bromus marginatus.

Seed transfer zones, which define the geographical relationship between adaptive traits and environmental factors, are increasingly used to determine the source populations that can be combined in restoration and revegetation. Climatic variables have been the most commonly used environmental data in transfer zone development, even though soils are also a primary selective force on plants. We assessed the importance of including soils in seed transfer zones using Bromus marginatus, a native grass used for restoration and revegetation in the western United States, as an example. Seeds were collected from 64 populations across Montana and Idaho and grown in a common garden for two years. We assessed among-population variation based on 11 traits related to germination rate, plant size, vigor, inflorescence number, survival, and carbon isotope discrimination (∆13 ), and used this variation to develop seed transfer zone maps using two approaches: (1) a conventional approach, using only climatic variables (climate only) and (2) an expanded approach that included soils and climatic variables (soils+climate). The most influential drivers of trait variation were factors related to soil water availability: soil order, available water content (AWC), and organic carbon levels. Populations from areas with andic soils, which have high soil AWC and soil organic carbon, had low germination, limited first-year survival, low ∆13 , and small seeds. Growing season length and winter temperatures were also predictive of trait variation. In comparison to climate-only models, soils+climate models explained 11% more variance (120% relative increase) for ∆13 and an average of 4.5% more (27% relative increase) for growth traits and survival. The transfer zone map developed using soils+climate differed from the climate-only map in both spatial pattern of ecotypic variation and number of transfer zones; the soils+climate map had more zones and a higher proportion of small (<4km2 ) transfer zone patches, while the climate-only map had more large patches >37km2 . Including soils in transfer zone development may identify adaptive trait variation that is obscured by large-scale differences in climate and could improve plant materials used for ecosystem management.

Relative performance of native cultivar and wild collected seed for grassland restoration

Availability of native plant materials for grassland restoration is limited. Even when available in sufficient quantities for ecological restoration projects, seed germination and establishment in relatively arid environments is often low. Poor revegetation results in soil erosion, invasion by non-native plant species and reduced aesthetics. Therefore, development and use of native plants bred for traits favourable for restoration should be considered. This study addressed whether native cultivar seed, commercially selected for advantageous growth characteristics, could improve native grass species reestablishment relative to wild collected seed. Cultivar and wild seed types of four cool season native grass species were investigated at three foothills fescue grassland reclamation sites: Bromus carinatus (mountain brome), Elymus trachycaulus (slender wheatgrass), Festuca idahoensis (Idaho fescue) and Koeleria macrantha (June grass). Seeding and transplanting were conducted and germination, emergence, density, height and health were determined from 2011 to 2013. No significant differences were detected between cultivar and wild seed types except laboratory germination, which was greater in the Elymus trachycaulus cultivar and in the wild collected Koeleria macrantha. Bromus carinatus performed poorly as a seedling from either seed type. Consistent trends in cultivar and wild seed performance, that reflected seed germination, were found for each species although results were not significant due to high variability. Results show that for these common grass species, seed type may not influence initial establishment. Differences among species were significant and varied with response measured, suggesting species characteristics are a key factor affecting native grass reestablishment. Species specific responses to seed type highlight the importance of making seed source decisions on a species basis.

Temporal priority effects on competition are not consistent among intermountain grassland species

Previous work indicates that priority effects exist, but mechanisms are not well understood. So we explored shifts in competitive outcomes and intensities as a potential general mechanism. In a standard greenhouse experiment the temporal priority effects of the target species Pseudoroegneria spicata and its competitive responses to five receptor species, i.e., Bromus ciliatus, Bromus marginatus, Coreopsis tinctoria, Senecio atratus, and Solidago canadensis were evaluated. P. spicata adults with a high root: shoot ratio had a significant inhibitory priority effect on B. ciliatus, B. marginatus, and C. tinctoria. Compared with the target species, under later and simultaneous sowing, B. ciliatus, B. marginatus, C. tinctoria, and S. atratus exhibited an increasing trend in terms of competition. However, S. canadensis did not display priority effects. In addition, the gram per gram competitive effect of P. spicata depended on the receptor species in the following order: B. marginatus > B. ciliatus > C. tinctoria > S. atratus. There were positive relationships between the relative interaction indices and the root: shoot ratios in B. ciliatus, B. marginatus, and C. tinctoria, thereby suggesting that the early germination or emergence of P. spicata may reduce the root: shoot ratios of these receptors. The results of this study indicate that priority effects occurred in early colonizers with high root: shoot ratios and greater competitive capacities.

The effect of feedstock composition and taxonomy on the products distribution from pyrolysis of nine herbaceous plants

The effect of feedstock composition and taxonomy on the products distribution from pyrolysis of nine herbaceous plants was evaluated. Specifically, eight members of the Poaceae family and one member of the Fabaceae family were pyrolyzed in a fixed bed reactor to a final temperature of 700°C. All samples resulted in a medium-energy CO2-rich gas and a phenol-rich liquid. The type of lignin rather than the overall lignin content was found to influence the phenols yield. All samples produced char with a suitable C/N ratio; eight plants produced char with high polarity; and only one sample (i.e., mountain brome) resulted in char with a sufficient aromaticity to be applied to soil. Low carbonization was associated with a high content of inorganic elements that were most likely deposited on the char's surface and blocked vaporization. The product distributions were dependent on (i) chemical and biochemical composition of feedstock, (ii) secondary reactions of liquid and char, and (iii) the samples' taxonomy. Red clover from the Fabaceae family was found to be the most distinct, followed by mountain brome from the Triticodae group (Poaceae family), and the remaining members of the Poodae group (Poaceae family). The least divergence was found between the hybrid samples.

Can biochar be used as a seed coating to improve native plant germination and growth in arid conditions?

Direct seeding is a common large-scale restoration practice for revegetating arid and semi-arid lands, but success can be limited by moisture and temperature. Seed coating technologies that use biochar may have the potential to overcome moisture and temperature limitations on native plant germination and growth. Biochar is a popular agronomic tool for improving soil properties, such as water availability and nutrient retention and has been recently marketed, but not tested, as a seed coating. We analyzed the effect of biochar seed coating thicknesses on the germination and growth of four plant species native to western United States: mountain brome (Bromus marginatus), prairie junegrasss (Koeleria cristata), Wyeth's buckwheat (Eriogonum heracleoides), and western yarrow (Achillea millefolium). Across different temperature and water potential treatments using environmental chambers and polyethylene glycol (PEG) solutions, biochar coating applied at different thicknesses had either a neutral or negative effect on germination for all species. In the field, biochar seed coatings slightly improved mountain brome root weight and prairie junegrass cover. Our results, alongside the high economic expense of native plant seed and direct seeding operations, suggest that biochar, by itself, may not be an appropriate seed coating for improving native plant establishment.

Biochar Soil Amendment Effects on Arsenic Availability to Mountain Brome (Bromus marginatus )

Biochar is a renewable energy byproduct that shows promise for remediating contaminated mine sites. A common contaminant at mine sites is arsenic (As). In this study, the effects of biochar amendments to a mine-contaminated soil on As concentrations in mountain brome ( Nees ex Steud.) were investigated. In the biochar-amended soil, mountain brome had greater root biomass and decreased root and shoot As concentrations. X-ray absorption near-edge structure spectroscopy results showed that arsenate [As(V)] is the predominant species in both the nonamended and biochar-amended soils. Soil extraction tests that measure phosphate and arsenate availability to plants failed to accurately predict plant tissue As concentrations, suggesting the arsenate bioavailability behavior in the soils is distinct from phosphate. Results from this study indicate that biochar will be a beneficial amendment to As-contaminated mine sites for remediation.

Roadway Deicer Effects on the Germination of Native Grasses and Forbs

Normal seed germination of native herbaceous species can be reduced by high concentrations of deicer products and their constituent salts. Chloride salts are commonly used during the winter months in temperate climates to remove ice and snow. Although these products greatly improve driving conditions, they can have detrimental effects on the vegetation growing along highways. The purpose of this laboratory study was to determine the impact of a magnesium-based deicer product and a sodium-based deicer product and the major salts they contain on the germination and viability of several species of grasses and forbs native to Colorado and planted in revegetation seedings there. Seeds were placed on blotter paper saturated with either a water control, one of three concentrations of each of the deicing solutions, or one of three concentrations of a pure NaCl or MgCl2 solution. Increasing concentrations of salt ions generally resulted in delayed and reduced normal seed germination, especially the sodium- and magnesium-based deicer solutions. Germination for most species was lower when seeds were grown in deicer solution compared with germination percent of seeds grown in the pure salt solutions. Some species were more tolerant of one of the salts and deicers. Species with C4 photosynthetic pathway were more tolerant than C3 species of high concentrations of both deicer products. Those species which attained the highest germination percent under moderate or high solution concentrations included blue grama, buffalograss, little bluestem, mountain brome, and slender wheatgrass.

Syngas production from pyrolysis of nine composts obtained from nonhybrid and hybrid perennial grasses.

A pyrolysis of compost for the production of syngas with an explicit H2/CO = 2 or H2/CO = 3 was investigated in this study. The composts were obtained from nonhybrid (perennial) grasses (NHG) and hybrid (perennial) grasses (HG). Discrepancies in H2 evolution profiles were found between NHG and HG composts. In addition, positive correlations for NHG composts were obtained between (i) H2 yield and lignin content, (ii) H2 yield and potassium content, and (iii) CO yield and cellulose content. All composts resulted in H2/CO = 2 and five of the nine composts resulted in H2/CO = 3. Exceptionally large higher heating values (HHVs) of pyrolysis gas, very close to HHVs of feedstock, were obtained for composts made from mountain brome (MB, 16.23 MJ/kg), hybrid Becva (FB, 16.45 MJ/kg), and tall fescue (TF, 17.43 MJ/kg). The MB and FB composts resulted in the highest syngas formation with H2/CO = 2, whereas TF compost resulted in the highest syngas formation with H2/CO = 3.

Mapping genetic variation and seed zones forBromus carinatusin the Blue Mountains of eastern Oregon, USAIn this article, mention of companies or trade names does not constitute an endorsement of any product or procedure.

Seed transfer zones ensure that germplasm selected for restoration is suitable and sustainable in diverse environments. In this study, seed zones were developed for mountain brome ( Bromus carinatus Hook. &amp; Arn.) in the Blue Mountains of northeastern Oregon and adjoining Washington. Plants from 148 Blue Mountain seed source locations were evaluated in common-garden studies at two contrasting test sites. Data on phenology, morphology, and production were collected over two growing seasons. Plant traits varied significantly and were frequently correlated with annual precipitation and annual maximum temperature at seed source locations (P &lt; 0.05). Plants from warmer locations generally had higher dry matter production, longer leaves, wider crowns, denser foliage, and greater plant height than those from cooler locations. Regression models of environmental variables with the first two principal components (PC 1 and PC 2) explained 46% and 40% of the total variation, respectively. Maps of PC 1 and PC 2 generally corresponded to elevation, temperature, and precipitation gradients. The regression models developed from PC 1 and PC 2 and environmental variables were used to map seed transfer zones. These maps will be useful in selecting mountain brome seed sources for habitat restoration in the Blue Mountains.

Mineral concentration in selected native temperate grasses with potential use as biofuel feedstock

Stands of native grasses along roadways, in buffer strips, riparian zones and grass prairies have potential utility as feedstock for bioenergy production. The sustainability of harvesting these stands is reliant, in part, on knowledge of the mineral concentration of the harvested grasses because removal of mineral nutrients such as phosphorus (P) and potassium (K) can impact subsequent biomass production and ecosystem services associated with these stands. Mineral content of biomass, particularly that of silicon (Si), chlorine (Cl), and sulfur (S) also impacts thermochemical conversion approaches that convert grasses into bioproducts. This study quantified Cl, S, Si, P and K in Bromus marginatus, Elymus glaucus, Poa secunda, Pseudoroegneria, Elymus lanceolatus, Elymus trachycaulus, Leymus cinereus, Leymus triticoides, and Pseudoroegneria spicata collected at three growth developmental stages from four plant introduction stations located in the western US. Differences ( P ⩽ 0.05) in mineral concentrations were associated with developmental stage, species, and location. Variability was greatest in Si concentrations which ranged from 1847 to 28620 mg kg −1, similar to those recorded in other grasses. Variability in Cl and S concentrations also occurred, but at less magnitude than that of Si. Concentrations of P and K, two mineral fertilizer components, varied approximately threefold among these grasses. Differences in mineral concentrations among these grasses were not completely dependent upon soil mineral content. Long-term evaluations of available soil mineral concentrations under contrasting management practices are needed to quantify how local conditions impact mineral cycling, and in turn, the sustainability of harvesting these stands. The data presented here establish baselines for these species in locations subject to contrasting environmental and microbiological conditions that affect mineral cycling and availability.

PLANT UPTAKE AND LEACHING OF SELENIUM IN MANURE- AND GYPSUM-AMENDED SOILS OF THE WESTERN PHOSPHATE RESOURCE AREA

Selenium (Se) that was once sequestered below the soil surface has been exposed to accelerated weathering conditions in the Western Phosphate Resource Area (WPRA), creating a potential threat to the ecosystem. The goal of this study was to evaluate the impact of an organic amendment (manure) and a sulfur-containing fertilizer on Se availability as determined by plant tissue concentrations and soil water chemistry. Tension lysimeters were used to sample soil water from treated plots. A greenhouse experiment was conducted to study the impact of these amendments on plant uptake of Se in a more controlled environment. A maximum of 7% of the soil water samples collected on any one date exceeded the suggested limit for water consumed by livestock (50 μg Se L−1) within the United States. Significant differences among treatments only occurred in the first sampling date when the mean Se concentration of water samples from the gypsum treatment was higher than in the manure and control treatments. In the greenhouse study, Se uptake by alfalfa (Medicago sativa) was higher than uptake by mountain bromegrass (Bromus marginatus), suggesting that alfalfa should not be planted on reclaimed mine soils within the WPRA. Although the use of organic amendments has been shown to increase the loss of Se through volatilization, our data suggest that it may result in a short-term increase in Se uptake, possibly caused by organic acids outcompeting selenite for soil-binding sites. These results can be used to help design and implement future remediation strategies in the WPRA.

Phylogeography of North American Mountain Bromes

Abstract Although native grasses are often desired and used for revegetation of disturbed areas, genetic differences may exist within and among natural and cultivated germplasm sources. This phylogeographic study compares geographic origin and genealogical linkages of 25 natural and cultivated germplasm sources of mountain brome (Bromus carinatus Hook. & Arn. [Poaceae]) from western North America. Significant variation among accessions (FST = 0.70) was detected by analysis of molecular variance (AMOVA), based on the number of amplified fragment length polymorphisms (AFLPs) between individual plants. Likewise, significant differences among 4 hierarchical genotypic groups, encompassing all but 5 unique accessions, were also detected (FCT = 0.47). This study identified at least one well-defined genealogical lineage, comprising 8 accessions, distributed over a broad geographic region and different ecosystems of western North America. Two other hierarchical groups, comprising 6 accessions and 3 accessions, were located within or near specific ecoregions. Results of this study indicate that natural genealogical lineages of cultivars, such as Garnet mountain brome, have dispersed and succeeded over broad geographical regions. However, more research and plant material work are needed before specific recommendations can be made over the entire species distribution.

Succession changes of temporary grass stands on set-aside land

The mixtures of &amp;lt;i&amp;gt;Bromus marginatus&amp;lt;/i&amp;gt; Nees ex Steud. + Coronilla varia L., Festuca pratensis L. + Lotus corniculatus L., Dactylis aschersoniana Graebn. + Trifolium repens L., Arrhenatherum elatius (L.) P. Beauv. ex J.S. et K.B. Presl + Medicago lupulina&amp;nbsp;L. were sown in rows of 125 mm in the year 1997 in Prague (chernozem, altitude 281 m a.s.l., average precipitation is 472 mm per year, average year temperature 9.3&amp;deg;C). The stands were one or three times per year cut with the mass removing or one or two times mulched. Botanical composition (by weight method), number of present species and agrobotanical groups (grasses, legumes, other dicotyledonous) coverage were measured during 6 years of vegetation. The species number was highest on plots cut 3 times (6&amp;ndash;17), it increased linearly. The sown species share in the dry mass yield was 75&amp;ndash;99% and the share of grasses decreased linearly with time. The significantly highest dry mass yield was reached when mulched two times per year Bromus marginatus Nees ex Steud. with Coronilla varia L. (till 14 t/ha ). The stands coverage was 43&amp;ndash;80%.

Performance of grass mixtures with mountain brome (Bromus marginatus Nees ex Steud.) in Central European lowlands

The seeding rate of 2 mil viable seeds of mountain brome cv. Tacit (28.1 kg/ha) is sufficient to establish a productive stand. The seeding amount can be decreased in the mixture with legumes. The growing in pure stand or in a simple mixture, e.g. with alfalfa, is appropriate, because of its low competitiveness. Mixtures with red clover were slightly worse, and mixtures with white clovers, resp. other grasses less suitable. The optimal cutting height of mountain brome to 5&amp;ndash;8 cm with regard to forage yield and persistence. Although this grass does not have special demands on site, it does not tolerate long-term dampness and floods. It is mainly used as silage grass with high dry matter production potential, with forage of better-than-average nutritive value, which is kept till the stage of early flowering.

Establishment of legumes and grasses overdrilled into Hieracium ‐infested montane tussock grasslands

The establishment of lotus (Lotus corniculatus), alsike clover (Trifolium hybridum), cocksfoot (Dactylis glomerata), and mountain brome (Bromus marginatus) were compared following overdrilling by an experimental strip seeder and a conventional triple disc drill in the presence and absence of paraquat herbicide. Drilling was carried out in late August or in late January at two sites on dry, undeveloped soils in the Mackenzie Basin, New Zealand. With August sowing, the number of lotus, cocksfoot, and brome, but not alsike seedlings at the end of the first growing season, were higher with the strip seeder drill than with the triple disc drill. With January sowing, lotus, alsike, and cocksfoot seedling numbers were higher with the strip seeder drill. Numbers declined over the following four years but the advantage of the strip seeder drill remained. Improved seedling nodulation, root development, root length, and shoot length were recorded with the strip seeder drill. Drill effects on legume herbage accumulation in Years 2–4 were not consistent. There were no significant herbicide effects on seedling establishment in the first growing season but herbicide increased legume herbage accumulation in Years 2–4, particularly with the triple disc drill. The higher seedling establishment and enhanced early seedling growth indicate the potential of the strip seeder drill technology particularly for establishing species with low seedling vigour.

Genomic organization of ribosomal RNA genes inBromus(Poaceae)

Restriction site maps of the rDNA genes of nine Bromus species are described. The rDNA repeat units ranged from 8.2 to 11.1 kbp in length. Intraspecific length variation was observed in the BamHI digestions in three of the nine species. Restriction site variation was observed mainly in the intergenic spacer (IGS) but was also detected in the coding region. A unique KpnI site was present in the IGS of Bromus tectorum and Bromus sericeus (subgenus Stenobromus); in addition, B. sericeus contained an extra EcoRI site. An additional DraI site was observed in the IGS of Bromus trinii (subgenus Neobromus). A BstEII site in the IGS, common to seven of the species, was absent in B. tectorum and B. sericeus. In the coding region, a 2.1-kbp BstEII fragment was present in four subgenera represented by Bromus inermis and Bromus erectus (subgenus Festucaria), Bromus marginatus and Bromus carinatus (subgenus Ceratochloa), B. tectorum and B. sericeus (subgenus Stenobromus), and B. trinii (subgenus Neobromus); a similar fragment of only 1.1 kbp was present in Bromus mollis and Bromus arvensis (subgenus Bromus). An additional BamHI site was present in the coding region of B. erectus. Ribosomal DNA data suggested that B. mollis and B. arvensis (subgenus Bromus) are genetically isolated from the other subgenera, which showed a derived relationship. Restriction site mapping of the rDNA genes could provide useful molecular data for species identification and population and evolutionary studies in Bromus. Key words : Bromus, ribosomal DNA, restriction maps, evolutionary relationships.

Productivity and water use of five pasture grasses in Canterbury

An experiment was conducted on a fertile Wakanui silt loam in 1991/1992 examining yield and water use of five perennial pasture grass species, Grasslands Hakari mountain brome (Bromus sirchensis), Grasslands Wana cocksfoot (Dactylis glomerata), Grasslands Roa tall fescue (Festuca arundinacea), Grasslands Marsden perennial ryegrass (L&amp;m perenne x L&amp;urn hybridum), Grasslands Maru phalaris (Phalaris aquatica). From 8 November, 1991 until 31 March, 1992 the highest yields were from Hakari and Maru at 11370 and 10870 kg/ha. Marsden, Wana and Roa yielded 8960,875O and 8190 kg/ha respectively. From late January until the end of March growth conditions were not limited by water stress or nutrients. Pre-irrigation yields, when minfall limited growth were 3840,3570, 2720, 2520 and 2290 kg/ha for Hakari, Maru, Marsden, Wana and Roa respectively. Total water use was not significantly different between species and averaged 400 mm. Water use efficiency (WUE) was significantly higher for Hakari and Maru at 30.1 and 27.9 kg DM/ha/mm respectively. The other three species had WUE's less than 23 kg DM/ ha/mm of water. Neutron probe measurements showed all species extracted soil water from a depth of at least 110 cm. Keywords Bromus sitchensis, Dactylis glomerata, Festuca arundinacea, Lolium perenne x L&amp;urn hybridum, Phalaris aquatica, root depth, water use, water use efficiency, yield

Genetic Diversity of Plant Species in Glacier National Park: Implications for Management

Genetic diversity, as the fundamental resource of Glacier National Park (GNP), is central to the characterization of biodiversity present in GNP. Preserving the genetic variation in species maintains their intrinsic flexibility to deal with variable abiotic and biotic environments. Although often not readily apparent as visible morphologic (phenotypic) differences, genetic variation may occur 1) between individuals within a population and 2) between populations of a species. Managers need to consider these two components of genetic variation when mediating the effects of human disturbance in GNP. However, very little is currently known about these levels of genetic organization in GNP species. Our three year project examines the presence and patterns of genetic variation in two GNP species: strawberry (Fragaria virginiana Duchesne) and mountain brome (Bromus carinatus Hook. and Arn.). We are quantifying the amount and distribution of genetic and phenotypic variation using quantitative genetic and electrophoretic methods and are identifying phenotypic characters subject to natural selection, i.e., those characters important for survival and reproduction differences in populations.

Herbicides for Control of Tall Larkspur (Delphinium barbeyi)

Control of tall larkspur on mountain rangelands would substantially reduce cattle poisoning. Several herbicides were evaluated for their control of tall larkspur in subalpine and aspen vegetation types. Glyphosate (2.2 kg ai ha−1) and picloram (2.2 kg ae ha−1) killed more than 88% of larkspur plants in both vegetation types. Clopyralid and triclopyr were ineffective at comparable rates. Metsulfuron (88 and 138 g ai ha−1) provided variable control. Glyphosate is nonselective and killed all perennial vegetation, except for Thurbers fescue and mountain brome in the aspen type. Picloram applied at 4.5 kg ha−1suppressed grasses on the subalpine site, but allowed grasses to increase at lower rates. All herbicides reduced forb cover.