نتایج جستجو برای: over grazing
تعداد نتایج: 1149418 فیلتر نتایج به سال:
Natural resources have been attracted a great deal of attentions and have been frequently exploited for many years. Dust is one of natural disasters mainly in recent years; here, in south west of Iran, it had destroyed the rangelands. The dust has detrimental effects on the rangelands, livestock and livestock production. High concentrations of dust may lead to the coughing, nasal discharge, whe...
Many biodiversity experiments have demonstrated that plant diversity can stabilize productivity in experimental grasslands. However, less is known about how diversity-stability relationships are mediated by grazing. Grazing is known for causing species losses, but its effects on plant functional groups (PFGs) composition and species asynchrony, which are closely correlated with ecosystem stabil...
Tidal flow causes high temporal variability in environmental properties that impact ecosystem dynamics. Microbes such as phytoplankton are especially susceptible to tidal advection and mixing, and understanding their role in estuarine food webs and biogeochemical cycles requires information on their biomass and taxonomic composition over short time scales (e.g. tidal cycles). We conducted a sur...
Livestock grazing potentially has substantial influence on fuel characteristics in rangelands around the globe. However, information quantifying the impacts of grazing on rangeland fuel characteristics is limited, and the effects of grazing on fuels are important because fuel characteristics are one of the primary factors determining risk, severity, continuity, and size of wildfires. We investi...
Attention to the quality and quantity of forage plants, palatability and species preference, are among the information needed to properly manage pasture grazing. One of the prominent plants in the Nour Rud rangelands are Allium spp plants that have an acceptable distribution in the area. For the sake of the study, the preferred value of different species of Allium’s for Shal sheep with an avera...
We studied five lower forest–grassland ecotones in the Darhad Valley in northern Mongolia and investigated the effects of 20th Century grazing regimes and changes in grazing management on ecotone dynamics at a local scale. A total of 2968 Siberian larch (Larix sibirica) trees were cored and tree-age distribution was constructed to determine 20th Century tree establishment. Tree age and location...
Research was conducted on the effects of rotational grazing (RG) compared to continuous grazing (CG) on the behavior of cattle grazing on rangelands. Different livestock den&tics in the RG treatments were created by varying the size of paddocks in a 4651a, U-paddock, cell deaigntd RG treatment stocked at a rate of 3.6 ha/cow/yr. Paddock sizes of 30 and lo-ha were used to simulate RG with 14 (RG...
Livestock grazing can be used as a key management tool for maintaining healthy ecosystems. However, the effectiveness of using grazing to modify habitat for species of conservation concern depends on how the grazing regime is implemented. Timing of grazing is one grazing regime component that is less understood than grazing intensity and grazer identity, but is predicted to have important impli...
The design, fabrication and performance of a novel and highly sensitive micro-reactor device for performing in situ grazing-incidence X-ray scattering experiments of model catalyst systems is presented. The design of the reaction chamber, etched in silicon on insulator (SIO), permits grazing-incidence small-angle X-ray scattering (GISAXS) in transmission through 10 µm-thick entrance and exit wi...
Forum Effects of Grazing Pressure on Efficiency of Grazing on North American Great Plains Rangelands
Comparisons of stocking rates across sites can be facilitated by calculating grazing pressure. We used peak standing crop and stocking rates from six studies in the North American Great Plains (Cheyenne, Wyoming; Cottonwood, South Dakota; Hays, Kansas; Nunn, Colorado; Streeter, North Dakota; and Woodward, Oklahoma) to calculate a grazing pressure index and develop relationships for harvest effi...
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