30 Years Of Medusahead: Return To Fly Blown Flat

Delmas, R.; Young, James A.

doi:10.2458/azu_rangelands_v23i3_wagner

Cited by 3 publications

(3 citation statements)

References 3 publications

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“…Protection from grazing for 65 years has not prevented cheatgrass invasion. Wagner et al (2001) discovered the same phenomenon with medusahead rye (Taeniatherum asperum…”

Section: Cover and Densitymentioning

confidence: 70%

Vegetation Change After 65 Years of Grazing and Grazing Exclusion

Courtois

Perryman

Hussein

2004

Rangeland Ecology & Management

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The Nevada Plots exclosure system was constructed in 1937 following passage of the Taylor Grazing Act to assess long-term effects of livestock grazing on Nevada rangelands. A comparison of vegetation characteristics inside and outside exclosures was conducted during 2001 and 2002 at 16 sites. Data analysis was performed with a paired t test. Out of 238 cover and density comparisons between inside and outside exclosures at each site, 34 (14% of total) were different (P < 0.05). Generally, where differences occurred, basal and canopy cover were greater inside exclosures and density was greater outside. Shrubs were taller inside exclosures at 3 sites grazed by sheep (Ovis aries). Perennial grasses showed no vertical height difference. Aboveground plant biomass production was different at only 1 site. Plant community diversity inside and outside exclosures were equal at 11 of 16 sites. Species richness was similar at all sites and never varied > 4 species at any site. Few changes in species composition, cover, density, and production inside and outside exclosures have occurred in 65 years, indicating that recovery rates since pre Taylor Grazing Act conditions were similar under moderate grazing and grazing exclusion on these exclosure sites. Resumen El sistema de exclusiones de Nevada se construyó en 1937, después de ser aprobada el Acta Taylor de Apacentamiento, para evaluar los efectos a largo plazo del apacentamiento del ganado sobre los pastizales de Nevada. Durante los años 2001 y 2002, en 16 sitios se condujo una comparación de las características de la vegetación dentro y fuera de las exclusiones. El análisis de los datos se llevo a cabo mediante pruebas de t-student para muestras apareadas. De 238 comparaciones de cobertura y densidad de la vegetación dentro y fuera de las exclusiones, 34 de ellas (14% del total) fueron diferentes (P < 0.05). Generalmente, donde ocurrieron las diferencias, la cobertura basal y de la copa fueron mayores dentro de las exclusiones y la densidad fue mayor fuera de ellas. En tres sitios apacentados con ovinos (Ovis aries) los arbustos fueron mas altos dentro de las exclusiones. Los zacates perennes no mostraron diferencias verticales de altura. La producción de biomasa vegetal aérea fue diferente solo en un sitio. La diversidad de la comunidad vegetal dentro y fuera de las exclusiones fue igual en 11 de los 16 sitios. La riqueza de especies fue similar en todos los sitios y nunca varió por más de 4 especies en ninguno de ellos. Pocos cambios han ocurrido en 65 años en la composición de especies, cobertura, densidad y producción dentro y fuera de las exclusiones, indicando que en estos sitos de exclusión las tasas de recuperación anteriores a las condiciones establecidas por el Acta Taylor fueron similares bajo un apacentamiento moderado y la exclusión al apacentamiento.

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“…Protection from grazing for 65 years has not prevented cheatgrass invasion. Wagner et al (2001) discovered the same phenomenon with medusahead rye (Taeniatherum asperum…”

Section: Cover and Densitymentioning

confidence: 70%

Vegetation Change After 65 Years of Grazing and Grazing Exclusion

Courtois

Perryman

Hussein

2004

Rangeland Ecology & Management

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“…On these sites, medusahead may invade regardless of the presence or absence of grazing. On a low sagebrush site with high clay content medusahead frequency was approximately 30% on both, a site that had been protected from grazing for over 30 years and on a nearby grazed site, though neither site had medusahead at the time the exclosure was constructed (Wagner et al 2001).…”

Section: Managementmentioning

confidence: 99%

Medusahead Ecology and Management: California Annual Grasslands to the Intermountain West

Nafus

Davies

2014

Invasive plant sci. manag.

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The spread of medusahead across the western United States has severe implications for a wide range of ecosystem services. Medusahead invasion reduces biodiversity, wildlife habitat and forage production, and often leads to increased fire frequency and restoration costs. Medusahead is problematic in the Intermountain West and California Annual Grasslands. The last review of medusahead ecology and management was completed 20 years ago. Since the last review, there have been scientific advances in medusahead management suggesting a significant need to develop an up-to-date synthesis. Medusahead continues to pose a serious threat to rangeland ecosystems. In this synthesis, we present new information regarding the ecology of medusahead, suggest a framework for managing medusahead based on invasion level, and identify research needs to further improve management of this invasive annual grass. Success of different management practices varies between the Intermountain West and California Annual Grasslands, signifying that the best management practices are those specifically tailored with consideration of climate, soil, plant community characteristics, and management objectives. Prevention and control treatments that are useful in the Intermountain West may not be practical or effective in the California Annual Grasslands and vice-versa.

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“…When a new invasive species has been established, ARS scientists work to understand exactly what the biological situation is, and how/why is it occurring 17–19. This problem assessment is often conducted in parallel with an immediate action program to eradicate or at least retard the spread and impact of a new invasive pest.…”

Section: The Role Of the Ars In Invasive Species Managementmentioning

confidence: 99%

Invasive species research in the United States Department of Agriculture–Agricultural Research Service

Carruthers¹

2003

Pest Management Science

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ABSTRACr The effects of K-deficiency on carbon exchange rates (CER), photo-synthate partitioning export rate, and activities of key enzymes involved in sueme metabolism were studied in soybean (Glycias max I.] Merr.) leaves. The different parameters were monitored in mature leaves that had expanded prior to, or during, imposition of a complete K-deficiency (plants received K-free nutrition solution). In general, recently expanded leaves had the highest concentration of K, and imposition of K-stress at any stage of leafexpansion resulted in decreased K concentrations relative to control plants (10 millimolar K). A reduction in CER, relative to control plants, was only observed in leaves that expanded during the K-stress. Stomatal conductance also declined, but this was not the primary cause of the decrease in carbon fixation because internal CO2 concentration was unaffected by K-stress. Assimilate export rate from K-deficient leaves was reduced but relative export, calculated as a percentage of CER, was similar to control leaves. Over all the data, export rate was correlated positively with both CER and activity of sucrose phosphate synthase in leaf extracts. K-deficient leaves had higher concentrations of sucrose and hexose sugars. Accumulation ofhexose sugars was associated with incesed activities of acid invertase. Neutral invertase activity was low and unaffected by K-nutrition. It is concluded that decreased rates of assimilate export are a ed with decreased activities of sucrose phosphate synthase, a key enzyme involved in sucrose formation, and that accumulation of hexose sugars may occur because of increased hydrolysis of sucrose in K-deficient leaves. Availability of K is known to have a large impact on plant growth, in part at least, because of the effects of K-status on certain aspects of leaf cell metabolism (for review see Ref. 12). In particular, leaves of K-deficient plants generally have reduced rates of C-fixation and assimilate export. Decreased CERs2 are often associated with partial stomatal closure. Because ofthe role of K fluxes in stomatal aperture changes (24), it has often been assumed that the influence of K on photosynthesis could be attributed to stomatal closure (17, 21). However, more recent studies with sugarbeet (29), alfalfa (22), and cotton (15) have '

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30 Years Of Medusahead: Return To Fly Blown Flat

Cited by 3 publications

References 3 publications

Vegetation Change After 65 Years of Grazing and Grazing Exclusion

Vegetation Change After 65 Years of Grazing and Grazing Exclusion

Medusahead Ecology and Management: California Annual Grasslands to the Intermountain West

Invasive species research in the United States Department of Agriculture–Agricultural Research Service

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