نتایج جستجو برای: grazing

تعداد نتایج: 15163  

Journal: Desert 2010
a.a naghipour borj gh.a. dianati tilaki h. tavakoli m. haidarian aghakhani

Abstract Over the last fifty years, most of the semi-arid rangeland in Iran has been converted to cropland without an equivalent reduction in grazing animals. This shift has led to heavy grazing pressure on rangeland vegetation. The present study has been conducted in Sisab Research Station in the North Khorasan Province to evaluate effects of long-term grazing exclosures on biodiversity of ra...

ژورنال: مرتع 2022

Background and objectives: Rangeland suitability for livestock grazing is assessed by scoring criteria for vegetation, water resources and soil erosion. In this study, the suitability of Lar Absar rangeland in Mazandaran province for grazing domestic animals and herbivorous wildlife grazing was investigated. Many researchers have examined pasture suitability for grazing cattle, sheep, goats, an...

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...

2015
Begoña Martínez-Crego Pedro Arteaga Alexandra Ueber Aschwin H. Engelen Rui Santos Markus Molis Bayden D Russell

Grazing-induced plant defences that reduce palatability to herbivores are widespread in terrestrial plants and seaweeds, but they have not yet been reported in seagrasses. We investigated the ability of two seagrass species to induce defences in response to direct grazing by three associated mesograzers. Specifically, we conducted feeding-assayed induction experiments to examine how mesograzer-...

2007
K. D. Hambright W. R. Schaffner R. W. Howarth

Using in situ mesocosm experiments, we compared grazing rates, food-selection patterns and nutrient mineralization rates of a daphniid cladoceran and a diaptomid copepod to determine their infl uence on phytoplankton composition and the prevalence of N-fi xing cyanobacteria. We show that grazing and nutrient mineralization may act synergistically within a grazer taxon. Cladocerans exhibited non...

1998
CHARLES A. TAYLOR

A study was conducted to evaluate standing crop of forage and cattle diets for a ‘I-pasture high-intensity low-frequency (HILF) grazing system, and a ‘I-pasture short-duration grazing (SDG) system on the same area. A epasture, 3-herd (Merrill) deferred rotation grazing system was sampled as a standard for comparison. Standing crop of forage was highest for the HILF grazing system compared to th...

2005
J. R. Dolan

According to a recent global analysis, microzooplankton grazing is surprisingly invariant, ranging only between 59 and 74% of phytoplankton primary production across systems differing in seasonality, trophic status, latitude, or salinity. Thus an important biological process in the world ocean, the daily consumption of recently fixed carbon, appears nearly constant. We believe this conclusion i...

2000
Iain Fraser Tony Chisholm

The recent decision to continue cattle grazing in the VANP has not been uniformly welcomed. There exists significant scientific evidence detailing the environmental impact of grazing. This paper examines whether an opportunity has been missed to resolve the ongoing conflict that accompanies the continuation of grazing in the VANP. The potential of economic instruments in resolving this unique l...

Journal: :مرتع و آبخیزداری 0
محمد جعفری استاد، دانشکده منابع طبیعی، دانشگاه تهران، حسین آذرنیوند استاد، دانشکده منابع طبیعی، دانشگاه تهران احمد صادقی پور استادیار، دانشکده کویرشناسی، دانشگاه سمنان نادیا کمالی پور دکتری مرتعداری، دانشکده منابع طبیعی، دانشگاه تهران احمد حیدری دانشیار، دانشکده مهندسی و فناوری کشاورزی، دانشگاه تهران حسن مداح عارفی دانشیار، مؤسسه تحقیقات جنگل ها و مراتع

global warming and climate change have drawn special attention to soil and its potential for stable carbon sequestration. soils are the largest stores of carbon in terrestrial carbon cycle and contain about three times more carbon than vegetation cover and two times more than that of atmosphere. studying the effects of grazing on soil carbon storage is important because of the major role soil o...

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