The occurrence of Microcystis blooms is a worldwide concern due to the numerous adverse effects on zooplankton. We therefore hypothesized that the cyanobacterium Microcystis aeruginosa is harmful to rotifer growth. Population and individual experiments were conducted with the same proportional volumes of Chlorella and Microcystis for given food densities. Life-table parameters, life-history tra...

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...

Twelve ruminally cannulated and six intact crossbred beef steers were used in a randomized complete block design to evaluate the effects of stocking density of a riparian pasture in the Sierra Nevada mountains on grazing behavior, dietary selection, forage intake, digesta kinetics, and growth rates of Carex nebraskensis and Juncus balticus. Nine .5-ha pastures were assigned to one of three trea...

Identifying the effects of grazing is critical for the conservation, protection and sustainable use of arid grassland ecosystems. However, research regarding the ecological effects of grazing along mountainous elevation gradients is limited in arid areas, particularly at the regional scale. Using the Biome-BGC grazing model, we explored the effects of grazing on grassland net primary productivi...

Bermudagrass (Cynodon dactylon [L.] Pers.) is a major feed source for ruminants across the southeastern United States. In 4 consecutive yr, 3 different bermudagrass hybrids, Alicia, Jiggs, and Tifton-85, were evaluated under a low stocking rate as forage and hay sources. The nutritive value, in situ DM digestibility, and performance and grazing behavior of beef steers under similar management w...

‎in this paper‎, ‎first we discuss a local stability analysis of model was introduced by p‎. ‎j‎. ‎mumby et‎. ‎al‎. ‎(2007)‎, ‎with $frac{gm^{2}}{m+t}$ as the functional response term‎. ‎we conclude that the grazing intensity is the important parameter to control the existence or extinction of the coral reef‎. ‎next‎, ‎we consider this model under the influence of the time delay as the bifurcat...

Twelve ruminally cannulated and six intact crossbred beef steers were used in a randomized complete block design to evaluate the effects of stocking density of a riparian pasture in the Sierra Nevada mountains on grazing behavior, dietary selection, forage intake, digesta kinetics, and growth rates of Carex nebraskensis and Juncus balticus. Nine .5-ha pastures were assigned to one of three trea...

This study with grazing beef cows on the range was designed to explore the possibility of determining incremental energy expenditure (EE) in standing, traveling, and grazing relative to that in lying down, by means of continuous monitoring of EE, location, and activity by the heart-rate method, with Global Positioning System (GPS) collars, and by motion sensors in the GPS collars, respectively....

Performance and production of growing cattle (Bos taurus) on Coastal Bermudagrass [Cynodon dactylon (L.) Pers.] pasture are affected by forage allowance, but possible interactions with fertilizer nutrient source (i.e., inorganic vs. organic) and time have not been well described. We evaluated the effects of 3 nutrient sources with equivalent N rates: 1) inorganic, 2) crimson clover (Trifolium i...