نتایج جستجو برای: over grazing
تعداد نتایج: 1149418 فیلتر نتایج به سال:
Extensive livestock production has been Mongolia’s major industry for centuries and traditional nomadic herding lifestyle and Mongolia’s expansive rangelands sustain this industry. After the democratic election and economic liberalization in 1992, formerly state-owned collectives were disbanded and Mongolia’s livestock population was privatized. There was no longer a state institution to formal...
We used a fully factorial experimental design to examine the effects of fire season, simulated grazing and their interaction on the temporal stability (year-to-year variation in production) of the C4 bunchgrass, Bouteloua curtipendula, the C3 bunchgrass, Nassella leucotricha, and the C4 lawngrass, Buchloe dactyloides. Treatments included three levels of fire (winter fire, summer fire, and no fi...
Greenhouse gas (GHG) emissions from livestock grazing systems are contributing to global warming. To examine the influence of yak grazing systems on GHG fluxes and relationships between GHG fluxes and environmental factors, we measured carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) fluxes over three key seasons in 2012 and 2013 from a range of potential sources, including: alpine m...
The concept of ecosystem services--the benefits that nature provides to human's society--has gained increasing attention over the past decade. Increasing global abiotic and biotic change, including species invasions, is threatening the secure delivery of these ecosystem services. Efficient evaluation methods of ecosystem services are urgently needed to improve our ability to determine managemen...
Similar to other biomes across the globe, grasslands in the American Southwest have experienced significant changes to their historic composition and processes (Bahre, 1991; McPherson & Weltzin, 2000). Plant communities have been shaped by disturbances such as fire, grazing, and their interactions with climate. ‘Disturbance is a change in physical or biological factors that ultimately affects t...
A study was conducted to assess effects of stocking rate (SR) on grazing behavior and energy expenditure (EE) by growing sheep and goat wethers co-grazing grass/forb pastures. Grazing was for 16-week periods in 2002 and 2003. Pastures consisted of various grasses, primarily bermudagrass (Cynodon dactylon) and johnsongrass (Sorghum halepense), and forbs (e.g., ragweed; Ambrosia spp.). Sheep (Kha...
Defining historic grazing pressures and rangeland management is vital if early landscape threshold crossing and long–term trajectories of landscape change are to be properly understood. In this paper we use a new environmental simulation model, Búmodel, to assess two contrasting historical grazing landscapes in Mývatnssveit Iceland for two key periods—the colonization period (ca. Landnám, A.D. ...
root morphological and distribution responses of signal grass (brachiaria decumbens) to long-term cattle grazing were examined in a tropical pasture in malaysia. the treatments were no grazing by cattle and grazing at a moderate stocking density (2.7 animal unit/ha) under rotational grazing for 33 years. the method consists of taking soil core using a soil corer to a depth of 30 cm and extracti...
Understanding the plant-pest interaction under warming with grazing conditions is critical to predict the response of alpine meadow to future climate change. We investigated the effects of experimental warming and grazing on the interaction between plants and the grassland caterpillar Gynaephora menyuanensis in an alpine meadow on the Tibetan Plateau in 2010 and 2011. Our results showed that gr...
Multiparous beef cows were managed to achieve marginal (BCS = 4.7 ± 0.07; n = 106) or good (BCS = 6.6 ± 0.06; n = 121) body condition (BC) to determine the influence of forage environment on BW and BC changes, intramuscular fat percentage (IMF), rump fat (RF), and serum hormones during 2 yr. Cows within each BC were randomly assigned to graze either common bermudagrass (CB; n = 3 pastures/yr) o...
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