Restoration of Exotic Annual Grass-Invaded Rangelands: Importance of Seed Mix Composition

2014 ◽  
Vol 7 (2) ◽  
pp. 247-256 ◽  
Author(s):  
Kirk W. Davies ◽  
Dustin D. Johnson ◽  
Aleta M. Nafus
Keyword(s):  
Species Richness ◽  
Life Forms ◽  
Perennial Grasses ◽  
Annual Grass ◽  
Herbaceous Vegetation ◽  
Plant Life ◽  
Annual Grasses ◽  
Exotic Annual Grass ◽  
Resistance To Invasion ◽  
Plant Life Form

AbstractRestoration of exotic annual grass-invaded rangelands is needed to improve ecosystem function and services. Increasing plant species richness is generally believed to increase resistance to invasion and increase desired vegetation. However, the effects of species richness and individual plant life forms in seed mixes used to restore rangelands invaded by exotic annual grasses have not been investigated. We evaluated the effects of seeding different life forms and increasing species richness in seed mixes seeded after exotic annual grass control to restore desirable vegetation (perennial herbaceous vegetation) and limit exotic annual grasses at two sites in southeastern Oregon. We also investigated the effects of seeding two commonly used perennial grasses individually and together on plant community characteristics. Large perennial grasses, the dominant herbaceous plant life form, were the most important group to seed for increasing perennial herbaceous vegetation cover and density. We did not find evidence that greater seed mix species richness increased perennial herbaceous vegetation or decreased exotic annual grass dominance more than seeding only the dominant species. None of the seed mixes had a significant effect on exotic annual grass cover or density, but the lack of a measured effect may have been caused by low annual grass propagule pressure in the first couple of years after annual grass control and an unusually wet-cool spring in the third year post-seeding. Although our results suggest that seeding only the dominant plant life form will likely maximize plant community productivity and resistance to invasion in exotic annual grass-invaded northern Great Basin arid rangelands, seeding a species rich seed mix may have benefits to higher tropic levels and community stability. Clearly the dominant species are the most prudent to include in seed mixes to restore exotic annual grass-invaded plant communities, especially with finite resources and an increasingly large area in need of restoration.

scholarly journals Characterizing Land Surface Phenology and Exotic Annual Grasses in Dryland Ecosystems Using Landsat and Sentinel-2 Data in Harmony

2020 ◽  
Vol 12 (4) ◽  
pp. 725 ◽  
Author(s):  
Neal J. Pastick ◽  
Devendra Dahal ◽  
Bruce K. Wylie ◽  
Sujan Parajuli ◽  
Stephen P. Boyte ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Data Mining ◽  
Land Surface ◽  
Western United States ◽  
Grass Cover ◽  
Annual Grass ◽  
Annual Grasses ◽  
Dryland Ecosystems ◽  
Exotic Annual Grass ◽  
Sentinel 2

Invasive annual grasses, such as cheatgrass (Bromus tectorum L.), have proliferated in dryland ecosystems of the western United States, promoting increased fire activity and reduced biodiversity that can be detrimental to socio-environmental systems. Monitoring exotic annual grass cover and dynamics over large areas requires the use of remote sensing that can support early detection and rapid response initiatives. However, few studies have leveraged remote sensing technologies and computing frameworks capable of providing rangeland managers with maps of exotic annual grass cover at relatively high spatiotemporal resolutions and near real-time latencies. Here, we developed a system for automated mapping of invasive annual grass (%) cover using in situ observations, harmonized Landsat and Sentinel-2 (HLS) data, maps of biophysical variables, and machine learning techniques. A robust and automated cloud, cloud shadow, water, and snow/ice masking procedure (mean overall accuracy >81%) was implemented using time-series outlier detection and data mining techniques prior to spatiotemporal interpolation of HLS data via regression tree models (r = 0.94; mean absolute error (MAE) = 0.02). Weekly, cloud-free normalized difference vegetation index (NDVI) image composites (2016–2018) were used to construct a suite of spectral and phenological metrics (e.g., start and end of season dates), consistent with information derived from Moderate Resolution Image Spectroradiometer (MODIS) data. These metrics were incorporated into a data mining framework that accurately (r = 0.83; MAE = 11) modeled and mapped exotic annual grass (%) cover throughout dryland ecosystems in the western United States at a native, 30-m spatial resolution. Our results show that inclusion of weekly HLS time-series data and derived indicators improves our ability to map exotic annual grass cover, as compared to distribution models that use MODIS products or monthly, seasonal, or annual HLS composites as primary inputs. This research fills a critical gap in our ability to effectively assess, manage, and monitor drylands by providing a framework that allows for an accurate and timely depiction of land surface phenology and exotic annual grass cover at spatial and temporal resolutions that are meaningful to local resource managers.

scholarly journals Changes in yellow bristle grass (Setaria pumila) abundance after drought implications for pasture management

2009 ◽  
Vol 62 ◽  
pp. 211-216 ◽  
Author(s):  
K.N. Tozer ◽  
T.K. James ◽  
C.A. Cameron
Keyword(s):  
Key Management ◽  
Perennial Grass ◽  
Perennial Grasses ◽  
Botanical Composition ◽  
Annual Grass ◽  
Bare Ground ◽  
Pasture Management ◽  
Soil Calcium ◽  
Annual Grasses ◽  
Previous Summer

Yellow bristle grass (YBG) which is a summeractive annual grass reduces pasture quality and becomes unpalatable to stock as panicles mature Farmers are concerned that an extreme drought from November 2007 to March 2008 may have facilitated the spread of YBG and other summeractive annual grass weeds Botanical composition was assessed on 12 Waikato dairy farms in February 2009 and YBG abundance was related to key management factors These findings were compared with data collected from the same farms (February 2008) during the drought Between years ryegrass cover and the proportion of bare ground decreased These components were replaced by two summeractive annual grasses YBG and summer grass and to a lesser extent summeractive perennial grasses clovers and dicots In 2009 YBG cover was negatively associated with summeractive perennial grass cover and pH and positively associated with YBG cover in the previous summer and soil calcium levels

Effects of perennial species on the demography of annual grass weeds in pastures subject to seasonal drought and grazing

2009 ◽  
Vol 60 (11) ◽  
pp. 1088 ◽  
Author(s):  
K. N. Tozer ◽  
D. F. Chapman ◽  
R. D. Cousens ◽  
P. E. Quigley ◽  
P. M. Dowling ◽  
...  
Keyword(s):  
Population Growth ◽  
Field Experiment ◽  
Perennial Grass ◽  
Dactylis Glomerata ◽  
Suppressive Effect ◽  
Perennial Grasses ◽  
Perennial Species ◽  
Annual Grass ◽  
Annual Grasses ◽  
Hordeum Leporinum

A field experiment was established in a southern Australian temperate pasture to investigate the effects of identity and proximity of perennial grasses on the demography of the annual grasses Vulpia spp. (V. myuros, V. bromoides) and Hordeum leporinum (barley grass). Annual grasses were grown either alone or in mixtures, at different distances from rows of Dactylis glomerata (cocksfoot) and Phalaris aquatica (phalaris). Dactylis had a greater suppressive effect than Phalaris on Vulpia and Hordeum. Biomass, tiller production, and panicle production of annual grasses increased linearly with increasing distance from the perennial row. Tiller and panicle production were greater for Vulpia than Hordeum. The estimated rate of population growth (λ) for annual grasses was greater in Phalaris than in Dactylis and in Vulpia than in Hordeum, and increased with sowing distance from perennial grass rows. It was estimated that λ, when seeds were sown directly adjacent to a row of perennial grasses, was 1 and 0.4 for Vulpia and Hordeum, respectively, within Dactylis stands, and 7 and 3, respectively, within Phalaris stands. However, 15 cm from the row, λ reached 50 and 39 for Vulpia and Hordeum, respectively, within Phalaris stands, and 39 and 16, respectively, within Dactylis stands. In grazed, dryland pastures, perennial competition alone is therefore unlikely to prevent population growth of annual grasses, especially in systems heavily disturbed by grazing or drought. However, Dactylis showed more promise than Phalaris in limiting the abundance of these weeds.

scholarly journals Shifts in Riparian Plant Life Forms Following Flow Regulation

Forests ◽  
2020 ◽  
Vol 11 (5) ◽  
pp. 518 ◽  
Author(s):  
María D. Bejarano ◽  
Judith Sarneel ◽  
Xiaolei Su ◽  
Alvaro Sordo-Ward
Keyword(s):  
Species Richness ◽  
Relative Abundance ◽  
Life Form ◽  
Woody Species ◽  
Life Forms ◽  
River Regulation ◽  
Flow Regulation ◽  
Plant Life Forms ◽  
Plant Life ◽  
Riparian Plant

Flow regulation affects bordering riparian plant communities worldwide, but how different plant life forms are affected by river regulation still needs further research. In northern Sweden, we selected 10 rivers ranging from free-flowing to low, moderately, and highly regulated ones. In 94 reaches across those rivers, we evaluated the relative abundance of woody and herbaceous (i.e., graminoids and forbs) life forms, their species richness, and their relative presence. We also explored which, and to what extent, hydrological variables drove species assembly within each life form. The relative abundance and species richness of each life form decreased across river categories with increasing levels of regulation. This was particularly apparent in herbaceous life forms, and the most drastic decreases were observed in all life forms in moderately or highly regulated reaches. Additionally, when river regulation increased, the relative presence of many species from all life forms decreased. Unlike woody species, only a few new herbaceous species appeared in regulated reaches. A canonical correspondence analyses (CCA) revealed that a wide range of hydrological variables explained the occurrence of woody species, while fewer variables explained variation in the graminoid and forb life forms. We conclude that flow regulation and its intensity result into clear shifts in the relative abundance of different life forms, as well as in changes of within-group species richness and composition. Consequently, the modification of certain flow attributes in flow regulation schemes, as well as the intensity of these modifications, may alter the ratio between herbaceous and woody species, ultimately impacting the functions and benefits derived from each life form.

Landscape-Scale Rehabilitation of Medusahead (Taeniatherum caput-medusae)-Dominated Sagebrush Steppe

2012 ◽  
Vol 5 (4) ◽  
pp. 436-442 ◽  
Author(s):  
Roger L. Sheley ◽  
Edward A. Vasquez ◽  
Anna-Marie Chamberlain ◽  
Brenda S. Smith
Keyword(s):  
Scaling Up ◽  
Landscape Scale ◽  
Perennial Grasses ◽  
Sagebrush Steppe ◽  
Annual Grass ◽  
Heterogeneous Landscape ◽  
Single Entry ◽  
Annual Grasses ◽  
Winter Annual ◽  
Revegetation Strategies

AbstractProducers facing infestations of invasive annual grasses regularly voice the need for practical revegetation strategies that can be applied across broad landscapes. Our objective was to determine the potential for scaling up the single-entry approach for revegetating medusahead-infested rangeland to broader, more heterogeneous landscape-scale revegetation of winter annual grass–infested rangeland. We hypothesized, when applied on a highly variable landscape scale, the combination of imazapic and seeding would provide highest abundance of perennial grasses and lowest amount of annual grasses. Treatments included a control, seeding of crested wheatgrass (‘Hycrest’) and Sandberg's bluegrass, spraying (60 g ai ha−1 imazapic), and a simultaneously applied combination of spraying and seeding. The HyCrest and Sandberg's bluegrass seeding rates were 19 and 3.4 kg ha−1, respectively. The treatments were applied to large plots (1.4 to 8 ha) and replicated five times, with each replication located in different watersheds throughout southeastern Oregon. This study shows that the single-entry approach can be scaled up to larger landscapes, but variation within establishment areas will likely be high. This procedure should reduce the costs over multientry treatment applications and make revegetating annual grass–infested rangeland across landscapes more affordable.

Role of Size and Nitrogen in Competition between Annual and Perennial Grasses

2013 ◽  
Vol 6 (1) ◽  
pp. 87-98 ◽  
Author(s):  
L. Noelle Orloff ◽  
Jane M. Mangold ◽  
Fabian D. Menalled
Keyword(s):  
Life Histories ◽  
Perennial Grass ◽  
Leaf Size ◽  
Perennial Grasses ◽  
Downy Brome ◽  
Greenhouse Study ◽  
Bluebunch Wheatgrass ◽  
Annual Grasses ◽  
Exotic Annual Grass ◽  
N Enrichment

AbstractDiffering life histories contribute to difficulties establishing perennial grasses on lands dominated by exotic annual grasses. In a greenhouse study, we investigated to what extent allowing the perennial grass bluebunch wheatgrass to emerge before the exotic annual grass downy brome would increase its competitive ability and whether modifying nitrogen (N) would affect competition. We conducted an addition-series factorial experiment. In three cohort treatments, the two species were seeded concurrently or bluebunch wheatgrass was at the two- or four-leaf stage when downy brome was planted. N treatments were low (ambient) or high (N added to maintain 10 mg kg−1 [0.1286 oz lb−1]). Larger bluebunch wheatgrass avoided suppression by downy brome regardless of N. Under concurrent sowing, doubling downy brome density decreased bluebunch wheatgrass biomass by 22.6% ± 2.38 SE. In contrast, when bluebunch wheatgrass had a four-leaf size advantage, the same increase in downy brome density decreased bluebunch wheatgrass biomass by 4.14% ± 2.31. Larger bluebunch wheatgrass also suppressed downy brome more effectively, but N enrichment decreased the suppressive ability of bluebunch wheatgrass.

Distribution of plant life forms along an altitudinal gradient in the semi-arid valley of Zapotitlán, Mexico

2000 ◽  
Vol 11 (1) ◽  
pp. 39-42 ◽  
Author(s):  
Numa P. Pavón ◽  
Humberto Hernández-Trejo ◽  
Víctor Rico-Gray
Keyword(s):  
Altitudinal Gradient ◽  
Life Forms ◽  
Plant Life Forms ◽  
Plant Life ◽  
Semi Arid
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