نتایج جستجو برای: grazed
تعداد نتایج: 2190 فیلتر نتایج به سال:
Overgrazing has been the primary cause of grassland degradation in the semi-arid grasslands of the agro-pastoral transition zone in northern China. However, there has been little evidence regarding grazing intensity impacts on vegetation change and soil C and N dynamics in this region. This paper reports the effects of four grazing intensities namely un-grazed (UG), lightly grazed (LG), moderat...
A study was conducted to determine the abundance of potential foods and the feeding substrates and behaviors of the western cherry fruit fly, Rhagoletis indifferens Curran (Diptera: Tephritidae), in 2005, 2006, and 2007 in central Washington state. Aphid colonies with honeydew, a presumed food source for flies, were not seen on randomly selected branches of sweet cherry trees, Prunus avium L., ...
Herbivory, Current Velocity and Algal Regrowth: How Does Periphyton Grow When the Grazers Have Gone?
eaten it? Does it grow faster or differently from un-grazed algae? To address these questions, an experiment conducted in streamside channels documented the re-growth of algae following grazing by two mayfly species. We found that algal re-growth did not depend on which mayfly species ate it; rather, it was the duration of grazing that mattered. The longer algae was grazed, the faster it grew. ...
On a Flemish sandy loam soil, cut and grazed swards were compared at different levels of mineral nitrogen (N) fertilization. Economically optimal N fertilization rates were 400 (or more) and 200 kg N ha yr on cut and grazed swards respectively. Considering the amounts of residual soil nitrate-N in autumn, these N rates also met the current Flemish legal provisions, i.e. no more than 90 kg ha ni...
The importance of disturbance in prairie has long been recognized. Increasingly interest and research have focused on the action and interaction of multiple disturbances. The distribution of Flodman's thistle [Cirsiumflodmanii (Rydb.) Arthur] on ant mounds, badger mounds, buffalo wallows, and potholes and in a lightly and a moderately grazed pasture was compared at the Nature Conservancy's S. H...
Integrating use of seeded perennial cool-season grass pastures with native rangeland can increase available forage and provide a high plane of nutrition for grazing livestock. Our objective was to compare performance of yearling beef heifers grazing native rangeland with those grazing an integrated system that included seeded forages. Twice-replicated, 3-ha pastures seeded to either ‘Rosana’ we...
Cattle and sheep grazed together and separately from April to October during 3 yr. Initial forage composition was 29% Kentucky bluegrass (Poa pratensis L.), 11% white clover (Trifolium repens L.), and 60% weeds. There were six Angus cow-calf pairs or six ewes (1/2 Dorset x 1/4 Finn x 1/4 Rambouillet) with 11 lambs per each of three pasture replications for single animal species. Six cow-calf pa...
Impacts of livestock grazing in arid and semiarid environments are often concentrated in and around wetlands where animals congregate for water, cooler temperatures, and green forage. We assessed the impacts of winter-spring (November-May) cattle grazing on marsh vegetation cover and occupancy of a highly secretive marsh bird that relies on dense vegetation cover, the California Black Rail (Lat...
The field cricket Gryllus campestris used to be very common throughout Europe, but in recent decades its population has declined. We study ecology and behavior of crickets near the Odolanów, Poland, between 2009 2011, with emphasis on the effects of grazing of cattle and horses on insects population. We compared the number of burrows per square meter on both grazed and non-grazed areas and exam...
Intraspecific variation in the strength of inducible plant defenses plays a central role in the interactions between plants and herbivores. Studies of this variation are typically conducted in the greenhouse or laboratory rather than the field. We simultaneously manipulated densities of local consumers in the field within Maine and South Carolina populations of the smooth cordgrass Spartina alt...
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