نتایج جستجو برای: over grazing

تعداد نتایج: 1149418  

A. Gonzalez Rodriguez A.I. Roca Fernandez,

Successful pasture-based milk production systems pivot on balancing dairy cows’ feed requirements with seasonal and annual fluctuations in pasture production. In order to maximise cow production from grazing dairy systems, it is necessary to reach an efficient utilization of grazed grass for feeding cows and the development of appropriate grazing management systems designed to maximize daily pa...

Journal: :Environmental management 2014
Matthew R Freitas Leslie M Roche Dave Weixelman Kenneth W Tate

We examined long-term (10 years) meadow plant community responses to (1) livestock grazing under riparian grazing utilization limits; (2) suspension of livestock grazing; and (3) meadow site wetness and precipitation on the Inyo National Forest, California. Observed trends in meadow plant species richness, diversity, and frequency of soil stabilizing species were not significantly different bet...

Journal: :Journal of experimental marine biology and ecology 2001
S R. Jenkins R G. Hartnoll

The limpet Patella vulgata L. is an important microphagous grazer on intertidal rocky shores of north-west Europe, occurring across the wave exposure gradient. Groups of P. vulgata were selected at mid-tide level of two exposed shores and two sheltered, fucoid dominated shores on the Isle of Man, British Isles, and manipulated to equivalent densities and population structure. The level of grazi...

2013
Naomi J. Fox Glenn Marion Ross S. Davidson Piran C. L. White Michael R. Hutchings

Parasitic helminths present one of the most pervasive challenges to grazing herbivores. Many macro-parasite transmission models focus on host physiological defence strategies, omitting more complex interactions between hosts and their environments. This work represents the first model that integrates both the behavioural and physiological elements of gastro-intestinal nematode transmission dyna...

2007
Meg L. Pollock Colin J. Legg John P. Holland Chris M. Theobald

Expert opinion was sought on 2 issues relating to herbivory: seasonal sheep preferences for plant species and seasonal plant response to grazing. Expert opinion is commonly used to parameterize models: it is therefore important to assess its quality. Understanding the limitations of expert knowledge can allow prioritization of future research. Nine experts in plant or grazing ecology from Scotl...

2006
MALCOLM GIBB M. GIBB

Investigations into the behavioural responses by ruminants to differences in their grazing environment have led to improved understanding of the grazing process. This has proved useful in developing management strategies which are not only sympathetic to the animals’ natural behaviour, but can improve the level and efficiency of resource use. The components of grazing behaviour considered are a...

2008
Lance T. Vermeire Rodney K. Heitschmidt Marshall R. Haferkamp

Grazing systems may alter botanical composition and productivity of grasslands through differential use in time, space, or intensity. Seven simulated grazing treatments were applied six years in eastern Montana, USA to determine effects on plant community composition and standing crop. Treatments were moderate stocking (28.8 AUD ha 1 year ) of cattle using 3-pasture summer rotation, season-long...

Journal: :Journal of experimental marine biology and ecology 2001
R E. Forrest M G. Chapman A J. Underwood

Wax discs have been used previously on intertidal rocky shores to record the grazing activity of gastropods. This study has evaluated this methodology for recording grazing of four common intertidal microalgal grazers on intertidal shores in New South Wales, Australia. In the laboratory, the four species examined-the patellid limpet, Cellana tramoserica (Sowerby), the trochid, Austrocochlea por...

ژورنال: علوم آب و خاک 2013
زهرا کیانی سلمی, , شجاع قربانی دشتکی, , فایز رئیسی گهروئی , , نجمه قربانی قهفرخی, ,

Free and uncontrolled pasture grazing by animals may decrease soil aggregate stability through reductions in plant cover and subsequent soil organic C, and trampling. This could expose the soil surface layer to degradation and erosion. The objective of this study was to determine the influence of pasture management (free grazing, controlled grazing and long-term non-grazing regimes) on aggregat...

2013

Grazing flow passing over the quiescent fluid inside the cavity of a Helmholtz resonator can excite the resonator. When the frequency of the instabilities within the shear layer is near the natural frequency of the resonator then flow-excited resonance will occur. This process causes self-sustained periodic oscillations of the flow over the orifice of the resonator. Quantitative numerical predi...

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