Native Grass Species Research Articles

Germination responses of native and invasive Cerrado grasses to simulated fire temperatures

ABSTRACTBackground: Fire is an important ecological factor in the Cerrado (Brazilian savanna). However, comparative studies on the effect of high temperatures experienced during fires on seed germination of native and invasive grass species are few.Aims: To assess germination responses to simulated fire temperatures by seeds of invasive and native Cerrado grasses.Methods: Heat-shock treatments (50 °C, 70 °C, 90 °C, 110 °C, 130 °C or 150 °C) were applied to seeds of 10 species of native and invasive grasses. For each temperature, the seeds were heated in a dry-air flow for 2 or 5 min. This combination of temperatures and exposure times simulated the soil conditions during typical Cerrado fires.Results: Temperature treatment was significantly related to germination, and the effect varied according to species. Heat shock did not increase germination in either the native or the invasive species. Exposure time was important for only two species, and four species showed a significant increase in mean germination time.Conclusions: Species showed different tolerances to high temperatures. It was not possible to differentiate the native and invasive grasses only by their tolerance to high temperatures, suggesting that fire alone may not be an efficient management tool to control the invasive species studied here.

Monitoring soil cracking and plant parameters for a mixed grass species

Limited studies have investigated the effect of vegetation growth and evapotranspiration (Etr) on desiccation parameter – crack intensity factor (CIF) considering a single species. Moreover, the role of inherent shoot parameters [stomatal conductance (SC) and photosynthetic yield (Y-II)] is generally ignored, leaving gaps in the authors’ understanding of its effects on CIF. This letter monitors and quantifies the effects of plant parameters [SC, Y-II, Etr and vegetation density (VD)] on soil suction and consequent CIF for a native mixed grass species. The vegetation undergoes eight drying cycles in compacted soil under natural environmental conditions and controlled irrigation scheduling. It is seen that the grass species helped reducing the maximum CIF of bare soil by 20%. A VD growth of 40% restricts further increase in CIF. The measured Etr of the vegetation is found to be very low in the study and potentially not induce additional transpiration-induced suction that can generate excessive cracks in crop species. Furthermore, the measured SC in the current vegetation species with respect to reported SC of crop species provides evidence that SC regulates a species’ ability to transpire and induce suction. The Y-II values did not give a conclusive idea of its role in soil crack propagation.

Soil-borne seed pathogens: contributors to the naturalization gauntlet in Pacific Northwest (USA) forest and steppe communities?

Soil-borne seed pathogens are omnipresent but are often overlooked components of a community’s biotic resistance to plant naturalization and invasion. Using multi-year greenhouse experiments, we compared the seed mortality of single invasive, naturalized, and native grass species in sterilized and unsterilized soils collected from Pacific Northwest (USA) steppe and forest communities. Native Pseudoroegneria spicata displayed the greatest seed mortality, naturalized Secale cereale displayed intermediate seed mortality, and invasive Bromus tectorum was least affected by soil pathogens. Seed mortality across all three species was consistently greater in soils collected from steppe than soils collected from forest; seeds sown into sterilized steppe soil experienced half the overall seed mortality compared to seeds sown into unsterilized steppe soil. Soil sterilization did not affect grass seed mortality in forest soils. We conclude that (1) removing soil-borne pathogens with sterilization does increase native and non-native grass seed survival, and (2) soil-borne pathogens may influence whether an introduced species becomes invasive or naturalized within these Pacific Northwest communities as a result of differential seed survival. Soil-borne pathogens in these communities, however, have the greatest negative effect on the survival of native grass seeds, suggesting that the native microbial soil flora more effectively attack seeds of native plants than seeds of non-native species.

Grass survey of the Itremo Massif records endemic central highland grasses

Despite the substantial area covered by grasslands in Madagascar (65%), the taxonomy of the grasses (Poaceae), which represent the main plant component of these vegetation types, is still understudied. Inventories and detailed specimen identification work from 1 2 localities in the Itremo Massif Protected Area allowed us to compile a list of grasses present in the area. In total, members of eight subfamilies, 56 genera, and 99 species have been recorded from the Itremo Massif. Grasslands cover 75% of the Itremo Massif Protected Area and are dominated by Panicoideae (65%) and by C 4 plants. The genera Eragrostis and Panicum , with nine and eight species respectively, are the best represented genera in Itremo. Eragrostis betsileensis and Tristachya betsileensis are the two species known to be local endemics. Twenty species are endemic to the central highlands, and a further 1 4 species are restricted to Madagascar. Five ecological groups of grasses were identified in the Itremo Massif: shade species in gallery forests, open wet area species, fire grasses, anthropogenic disturbance associated grasses and rock-dwelling grasses. Grasslands of the Itremo Massif are likely to be at least partly natural as shown by their richness in terms of endemic and native grass species. Conservation of such grasslands is thus an important issue, not only for grasses but for all species that inhabit these open canopy habitats.

Shoot morphology and alkaloid content of Epichloë endophyte–Festuca sinensis associations

The Chinese native cool-season perennial grass species Festuca sinensis Keng ex E.B.Alexeev exhibits frequent asymptomatic infections with an asexual Epichloë fungal endophyte. Six Festuca sinensis ecotypes were collected in different geographical locations. Endophyte-positive (E+) plants and corresponding endophyte-free (E–) plants of these six ecotypes were identified and then measured for shoot morphological characteristics including plant height, tiller number and biomass. Significant difference due to different host ecotype was observed in both E+ and E– plants. However, significant difference due to endophyte was observed in only one or two ecotypes. Concentration of endophyte-derived alkaloids and semi-quantitative endophyte colonisation in E+ plants were also evaluated. All E+ plants produced both lolitrem B and peramine alkaloids, and significant variation in alkaloid concentration due to host ecotype or endophyte genotype was observed. Analysis of semi-quantitative endophyte colonisation by using qPCR revealed significant differences between ecotypes. This suggested that host ecotype had large impacts whereas the endophyte had only a minor effect. The results showed that endophyte, host ecotype and their complex interaction affected performance of Festuca sinensis ecotypes.

Relative phytotoxicity of parthenium weed (Parthenium hysterophorus L.) residues on the seedling growth of a range of Australian native and introduced species

The invasive herbaceous species Parthenium hysterophorus L. (Asteraceae), commonly known as parthenium weed has rapidly become a significant weed in more than 30 countries. Parthenium weed litter taken from the introduced biotypes was relatively more phytotoxic than that taken from biotypes coming from the native range when tested on lettuce and this may indicate one reason for invasion success. However, no significant difference was observed in phytotoxicity to lettuce seedling growth when two Australian biotypes of parthenium weed were compared, one invasive and one non-invasive, indicating that invasiveness was not associated with litter phytotoxicity in all cases. Residue from the invasive parthenium weed biotype had a greater phytotoxic effect upon Australian native pasture grass species relative to the introduced pasture grass species with buffel grass (Cenchrus ciliaris L.) and bull Mitchell grass (Astreble sequarrosa C.E.Hubb) showing the greatest tolerance to parthenium weed phytochemicals. When compared with residue taken from plants that has a range of phytotoxic capacity, parthenium weed residue was considered to be only moderately phytotoxic suggesting that the phytotoxicity of its residue may not be the main reason for the plants invasive trait.

Fusarium graminearum: pathogen or endophyte of North American grasses?

Summary Mycotoxin‐producing Fusarium graminearum and related species cause Fusarium head blight on cultivated grasses, such as wheat and barley. However, these Fusarium species may have had a longer evolutionary history with North American grasses than with cultivated crops and may interact with the ancestral hosts in ways which are biochemically distinct.We assayed 25 species of asymptomatic native grasses for the presence of Fusarium species and confirmed infected grasses as hosts using re‐inoculation tests. We examined seed from native grasses for the presence of mycotoxin‐producing Fusarium species and evaluated the ability of these fungi to produce mycotoxins in both native grass and wheat hosts using biochemical analysis.Mycotoxin‐producing Fusarium species were shown to be prevalent in phylogenetically diverse native grasses, colonizing multiple tissue types, including seeds, leaves and inflorescence structures. Artificially inoculated grasses accumulated trichothecenes to a much lesser extent than wheat, and naturally infected grasses showed little to no accumulation.Native North American grasses are commonly inhabited by Fusarium species, but appear to accommodate these toxigenic fungi differently from cultivated crops. This finding highlights how host identity and evolutionary history may influence the outcome of plant–fungal interactions and may inform future efforts in crop improvement.

Native Prairie Graminoid Host Plants of Minnesota and Associated Lepidoptera: A Literature Review

Native grasses act as host plants, providing food and shelter, for numerous Lepidoptera species during their larval stage. As grassland habitat decreases because of conversion to agriculture and urban areas, prairie specialist butterflies and moths have also declined. Addition of native species to urban and agriculture landscapes has been shown to benefit Lepidoptera communities in various ways. Native grasses have grown in popularity as a landscaping plant due to their low nutrient requirements, drought tolerance, and soil stabilization properties. However, the benefits of native grasses to Lepidoptera are not well known to many entomologists or horticulturists, let alone the average consumer. We reviewed the literature that identified native prairie graminoids as host plants for native Lepidoptera in Minnesota, especially plants widely available in the horticultural trade that could be planted for restoration or landscaping purposes. The context of the Lepidoptera and host plant associations found in the literature are described. In total, we found 36 Lepidoptera species that used 17 prairie graminoids as host plants cited in the literature. Three native grasses, Schizachyrium scoparium (Michx.) Nash, Andropogon gerardii Vitman and Panicum virgatum L. and were found to be used by the most Lepidoptera species, 11, 9, and 8, respectively. Most likely there are additional moth species that use these grasses as host plants because butterfly species tend to be better documented than moth species. The specific larval habits and host plant species were unknown for many species of moths that feed or are suspected to feed on graminoids, showing the need for further research in this area. This information can assist horticulturalists, ecologists, landscape planners, land managers, and homeowners in their decisions to buy and plant native grass species. In general, this knowledge provides increased awareness about the larval life stage of butterflies and moths to concerned citizens and green industry and further supports the importance of conserving native prairie to support and maintain Lepidoptera species.

Screening and Selection of Twenty Iranian Wheatgrass Genotypes for Tolerance to Salinity Stress during Seed Germination and Seedling Growth Stage

Desert wheatgrass (Agropyron desertorum L.), tall wheatgrass (Agropyron elongatum L.), and crested wheatgrass (Agropyron cristatum L.) are native cool-season grass species that exhibit potential as a low-input turfgrass. An increased understanding of the biochemical and physiological responses of wheatgrass species and genotypes to salt stress conditions is important for developing genotypes with enhanced tolerance to salinity. The objective of this study was to characterize the physiological and antioxidative properties in 20 Iranian wheatgrass genotypes and to observe their responses to salinity stress during seed germination and seedling growth stage. A completely randomized factorial design was used with two types of factors, four levels of salinity (0, 50, 100, and 150 mm of NaCl), wheatgrass genotypes, and three replicates. In this experiment, the results demonstrated that salinity limits the germination of Iranian wheatgrass genotype seeds. The result of this study showed that among the wheatgrass genotypes, ‘AD1’, ‘AD3,’ ‘AC6’, and ‘FA’ took the shortest average time to germinate. Higher levels of final germination percentage (FGP) were observed in ‘AD2’, ‘AD3’, and ‘AE5’ under salinity stress than other genotypes throughout the experiment. During a prolonged period of study, ‘AD1’ had greater rate of germination (GR) than other genotypes. Out of the 21 genotypes, five genotypes (‘AD1’, ‘AD2’, ‘AD3’, ‘AE5’, and ‘FA’ genotypes) were in the range of “salinity tolerant genotypes” cluster. The ‘AD1’, ‘AD2’, ‘AD3’, ‘AE5’, and ‘FA’ genotypes generally performed better than other genotypes under salinity conditions, mainly through maintaining higher enzymatic activities such as superoxide dismutase (SOD) (EC 1.15.1.1), catalase (CAT) (EC 1.11.1.6), ascorbate peroxidase (APX) (EC 1.11.1.11) and peroxidase (POD) (EC 1.111.1.7), and nonenzymatic antioxidant activities by glutathione (GSH). The ‘AD1’, ‘AD2’, ‘AD3’, ‘AE5’, and ‘FA’ genotypes also had higher proline levels and more of total nonstructural carbohydrates (TNC) content, lower malondialdehyde (MDA) content, and lower hydrogen peroxide content (H2O2).

Native salt-tolerant grass species for habitat restoration, their acclimation and contribution to improving edaphic conditions: a study from a degraded mangrove in the Indian Sundarbans

The Sundarbans is the largest continuous block of mangrove distributed over both India and Bangladesh and is threatened with pronounced erosion and mudflat degradation in its western reaches. Since 2013, considerable progress has been achieved through the restoration of highly degraded mudflats by the extensive utilization of four native grass species plantings, Porteresia coarctata, Myriostachya wightiana, Paspalum vaginatum, and Sporobolus virginicus. These grasses proved to exhibit the highest survival (80–90%) in the lower and middle intertidal zone and during the last three years (2013–2016) almost 6000 m2 area have been restored by the growth of these grasses. Increased osmolyte synthesis under degraded conditions in these native grasses offered osmotic protection and helped to expand and restore the mudflat to an elevation suitable for mangrove establishment. The rhizosphere of the four grasses was engaged in the decomposition cycle, releasing more nutrients, more nutrient cycling soil microbial enzymes, and encouraged high densities of nutrient cycling bacteria. The study demonstrates that stabilization and reclamation of the denuded mudflat by halotolerant grasses is an essential prerequisite for any successful mangrove restoration program. The facilitative role of the salt marsh is crucial to aid colonization by mangrove propagules.

Phenology of perennial, native grass, belowground axillary buds in the northern mixed-grass prairie.

Vegetative reproduction from belowground bud banks is the primary driver of grassland systems. Despite the importance of bud banks, the timing of recruitment and the crucial link between formation and maintenance is unknown. We assessed patterns of belowground bud development, dormancy, and mortality associated with three perennial native grasses in the northern Great Plains. Temperature and soil moisture were measured below the soil surface to determine relationships with belowground bud development. Blue grama (Bouteloua gracilis) generated more buds over winter that remained dormant; whereas, C3 species needle-and-thread (Hesperostipa comata) and western wheatgrass (Pascopyrum smithii), maintained limited dormant buds throughout winter. Soil temperature was a good predictor for C4 species bud production; whereas, soil moisture was a reliable predictor for C3 buds. Distinct differences existed between C4 species blue grama and C3 species needle-and-thread, whereas C3 species western wheatgrass (Pascopyrum smithii) was intermediate, indicating there is likely a species-specific continuum between the C3 and C4 extremes rather than a stark difference. The ability to predict belowground bud development is a novel insight to native perennial grasses. Native grass species' strategies and adaptability regarding belowground bud bank size and bud phenology are important factors optimizing tiller recruitment given the variable growing conditions. Patterns of bud dormancy and development will provide insight to the underlying mechanisms by which management practices and fluctuations in precipitation amount and growing season length can alter mixed-grass prairie plant community dynamics.

Outside the envelope: rare events disrupt the relationshipbetween climate factors and species interactions.

The order in which species arrive during community assembly can be an important driver of community composition and function. However, the strength of these priority effects can be variable, in part because of strong site and year effects. To understand how priority effects vary in importance with abiotic conditions, we initiated identical community assembly experiments in which we varied the timing of arrival of native and exotic grass species in each of 4 yr across three grassland sites in northern California. This uniquely replicated experiment tested the power of priority to determine initial community structure in a restoration context across a natural range of conditions. There were large and significant differences in both total seeded cover and the strength of priority across sites and years of initiation, confirming the suspicion that most ecological experiments may lack spatial and temporal generality. On the other hand, much of the variation in strength of priority could be related to climate. Strikingly, however, the model fit across the three sites and the first 3 yr of the study (the first nine experiments) was radically altered when we included the fourth year, which was characterized by an unusual weather pattern with higher temporal variability in rainfall (a rainfall pattern predicted to increase with climate change). This year produced relatively low strength of priority, supporting the suggestion that highly variable climates may be associated with lower strength of priority effects. Experiments that examine community assembly over a range of naturally occurring abiotic conditions enhance our ability to predict when priority effects will be important, allowing us to explore shifting patterns of community assembly in the face of climate change and optimize restoration strategies based on environmental conditions.

Clipping and irrigation enhance grass biomass and nutrients: Implications for rangeland management

Increasing frequency of drought and high herbivore pressure significantly affect individual grass functions in semiarid regions. Reseeding of degraded rangelands by native grass species has been recommended as a tool for restoration semiarid rangelands. However, how grass species used for reseeding respond to stressors has not been fully explored. We examined biomass allocation and nutrient contents of Cenchrus ciliaris and Chloris gayana in the semiarid Borana rangelands, Ethiopia. We tested clipped mature tufts of the same species for biomass allocation and nutritive values. Further, shifts in rainfall and herbivory were simulated by three irrigation and four clipping treatments, respectively, for newly established grasses in pot and field plot experiments. Aboveground biomass (AGB) significantly declined by up to 75% under increased clipping in mature tufts. In contrast, clipping significantly stimulated up to 152% higher AGB of newly established grasses. Lower irrigation reduced the AGB by 24 and 42% in C. ciliaris and in C. gayana, respectively. Clipping, further, significantly enhanced grass nutrients in grass tufts by up to 82 and 105% in C. ciliaris and C. gayana, respectively. Hence, management should focus on balancing this trade-off in mature grasses for nutritious rangeland production by clipping and storing for later supplemental feeding when grass nutrients drop. Further, young pastures should be moderately clipped/grazed for better establishment and biomass allocation. Additionally, our experiments established the first interactive effect of clipping and irrigation frequencies on the biomass allocation of native grasses in the semiarid Borana rangelands, Ethiopia. Knowledge of these interacting factors is deemed essential for policy makers to enhance productivity of degraded rangelands such as the Borana rangelands.

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.

Evaluation of six candidate DNA barcode loci for identification of five important invasive grasses in eastern Australia.

Invasive grass weeds reduce farm productivity, threaten biodiversity, and increase weed control costs. Identification of invasive grasses from native grasses has generally relied on the morphological examination of grass floral material. DNA barcoding may provide an alternative means to identify co-occurring native and invasive grasses, particularly during early growth stages when floral characters are unavailable for analysis. However, there are no universal loci available for grass barcoding. We herein evaluated the utility of six candidate loci (atpF intron, matK, ndhK-ndhC, psbE—petL, ETS and ITS) for barcode identification of several economically important invasive grass species frequently found among native grasses in eastern Australia. We evaluated these loci in 66 specimens representing five invasive grass species (Chloris gayana, Eragrostis curvula, Hyparrhenia hirta, Nassella neesiana, Nassella trichotoma) and seven native grass species. Our results indicated that, while no single locus can be universally used as a DNA barcode for distinguishing the grass species examined in this study, two plastid loci (atpF and matK) showed good distinguishing power to separate most of the taxa examined, and could be used as a dual locus to distinguish several of the invasive from the native species. Low PCR success rates were evidenced among two nuclear loci (ETS and ITS), and few species were amplified at these loci, however ETS was able to genetically distinguish the two important invasive Nassella species. Multiple loci analyses also suggested that ETS played a crucial role in allowing identification of the two Nassella species in the multiple loci combinations.

Effectiveness of Burning, Herbicide, and Seeding Toward Restoring Rangelands in Southeastern North Dakota

Many rangelands in southeastern North Dakota are invaded by Kentucky bluegrass (Poa pratensis L.) and/or smooth brome (Bromus inermis Leyss.). It may be especially difficult for native species to reestablish in rangelands dominated by Kentucky bluegrass and/or smooth brome due to these species’ competitive advantages. Relatively few studies have specifically compared the effectiveness of methods intended to reduce competition from Kentucky bluegrass and/or smooth brome before seeding with native species in southeastern North Dakota. In our current study, we evaluated the effects of five restoration treatments: 1) control (no seeding or competition-reduction treatments), 2) interseed (native seeds drilled into the existing plant community), 3) spring burn before drill seeding native species, 4) glyphosate application before drill seeding native species, and 5) spring burn plus glyphosate application before drill seeding native species on a degraded rangeland plant community. We installed the five treatments in fifteen 40 × 100 m plots in 2010. In 2015, we sampled the vegetation within each plot to determine whether the restoration methods increased total and/or native warm-season grass biomass, reduced Kentucky bluegrass and/or smooth brome biomass, or increased grass species richness. Although none of our restoration treatments impacted Kentucky bluegrass biomass, each of our restoration treatments increased grass species richness over the control. Including a glyphosate application before seeding with natives also increased total biomass, reduced smooth brome biomass, and increased native warm-season grass species richness. Thus, we suggest that the glyphosate application was a worthwhile addition at this location because it resulted in additional improvements to the invasive-dominated plant community.

Poa secunda local collections and commercial releases: A genotypic evaluation.

The genetics of native plants influence the success of ecological restoration, yet genetic variability of local seed collections and commercial seed releases remains unclear for most taxa. Poa secunda, a common native grass species in Intermountain West grasslands and a frequent component of restoration seed mixes, is one such species. Here, we evaluate the genetic variation of local Poa secunda collections in the context of wild populations and commercial seed releases. We evaluated AFLP markers for seven Poa secunda collections made over a 4000-hectare area and four commercial releases (High Plains, MT-1, Opportunity, and Sherman). We compare the genetic distance and distribution of genetic variation within and between local collections and commercial releases. The extent and patterns of genetic variation in our local collections indicate subtle site differences with most variation occurring within rather than between collections. Identical genetic matches were usually, but not always, found within 5 m2 collection sites. Our results suggest that the genetic variation in two Poa secunda releases (High Plains and MT-1) is similar to our local collections. Our results affirm that guidelines for Poa secunda seed collection should follow recommendations for selfing species, by collecting from many sites over large individual sites.

Root Functional Diversity of Native and Nonnative C3 and C4 Grass Species in Hawai‘i1

C3 and C4 plants are often reported to differ in functional traits and resource-use strategies, whereas nonnative plants may differ from native plants in functional traits, leading to different resource-use strategies that facilitate their invasion. In this study, we compared root functional traits of native and nonnative C3 and C4 grasses with the prediction that different resource acquisition strategies would be observed among these groups. We examined five root functional traits [mean diameter, specific root length, root tissue density, fine root percentage (diameter P P

Controlling Kentucky Bluegrass with Herbicide and Burning Is Influenced by Invasion Level

Kentucky bluegrass (Poa pratensis L.) invades northern Great Plains rangelands. On the Sheyenne National Grassland in southeastern North Dakota, three research sites, each with a different level of Kentucky bluegrass invasion, were chosen to evaluate effectiveness of burning and burning–herbicide combinations to control Kentucky bluegrass. Initial Kentucky bluegrass invasion levels were 37%, 77%, and 91% for LOW, MODERATE, and HIGH invaded sites, respectively. Within each invaded site, four replicated strips (20 by 60 m) were established, with half of each strip burned in late October 2005 and the other half burned in early May 2006. Herbicide treatments of (1) no herbicide, (2) 2.24 kg ha−1 of glyphosate, and (3) 0.43 kg ha−1 of imazapic were randomly assigned to 10 by 20 m subplots within each burn. Control plots were established at the same time. Relative basal cover of native grass, native forb, and Kentucky bluegrass was estimated annually using 50 10-point frames within each subplot. On the HIGH site in 2006, fall-burned plots with a spring glyphosate application had three times the native grass cover and only one fourth of the Kentucky bluegrass cover compared with controls. Similar results with the same treatment occurred at the MODERATE site. Native grasses became the most abundant plant community on these plots in the MODERATE and HIGH sites within 1 yr. Treatment differences were transitory, and the LOW site differed from the MODERATE and HIGH sites. In 2007, on fall-burned plots with spring glyphosate application, the amount of Kentucky bluegrass was 14% and 30%, and native grass species were 52% and 42% on the MODERATE and HIGH sites, respectively, which was similar to the initial values on the LOW site. These data emphasize the importance of initial invasion level in developing restoration strategies and provide evidence burning and herbicide combinations can be valuable management tools even on heavily invaded grasslands.

Metagenomics at grass roots

Metagenomics is a robust, interdisciplinary approach for studying microbial community composition, function, and dynamics. It typically involves a core of molecular biology, microbiology, ecology, statistics, and computational biology. Exciting outcomes anticipated from these studies include unraveling of complex interactions that characterize the ecological milieu of microbial communities. Diverse habitats from which metagenomes have been reported include human guts, caterpillar guts, thermal vents in oceans, ore deposits, polar caps, and even soils that adhere to plant roots. Knowledge generated from metagenomic projects has tremendous potential to beneflt human health, agriculture, and ecosystem functions. This article provides a brief history of technical advances in metagenomics, including DNA sequencing methods, and some case studies. A speciflc example is provided of microbial metagenomes found at the roots of native grass species (family Poaceae) that can grow on degraded lands undergoing revegetation.