Very little is known about the ability of the zooplankton grazer Daphnia pulicaria to reduce populations of Giardia lamblia cysts and Cryptosporidium parvum oocysts in surface waters. The potential for D. pulicaria to act as a biological filter of C. parvum and G. lamblia was tested under three grazing pressures (one, two, or four D. pulicaria grazers per 66 ml). (Oo)cysts (1 x 10(4) per 66 ml)...

In this study, a Taylor method is developed for numerically solving the high-order most general nonlinear Fredholm integro-differential-difference equations in terms of Taylor expansions. The method is based on transferring the equation and conditions into the matrix equations which leads to solve a system of nonlinear algebraic equations with the unknown Taylor coefficients. Also, we test the ...

Pasture renovation entails introduction of desirable forage species, usually legumes such as red clover (Trifolium pratense L.), white clover (Trifolium repens L.) or birdsfoot trefoil (Lotus corniculatus L.), into a grass dominated pasture. A commonly used method of pasture renovation consists in drilling seeds into the grass sod (sod-seeding). Introduced legumes benefit the pasture in three w...

Plant-herbivore interactions are hypothesized to drive vole population cycles through the grazing-induced production of phytoliths in leaves. Phytoliths act as mechanical defences because they deter herbivory and lower growth rates in mammals. However, how phytoliths impair herbivore performance is still unknown. Here, we tested whether the amount of phytoliths changes tooth wear patterns. If c...

INTRODUCTION A fence was erected across the St Col Ridge of Campbell Island (Fig. 1) early in 1970, and feral sheep (Ovis aries) (Wilson and Orwin, 1964) were exterminated north of the line (Bell and Taylor, 1970). The aims of the fencing project were – 1. to assess the effects of sheep grazing on the native biota; 2. to remove the immediate threat to plant species and communities; 3. to help d...

Wild burros (Equus asinus), protected by the 1971 Wild Free-Roaming Horse and Burro Act on some federal lands but exotic animals many ecologists and resource mangers view as damaging to native ecosystems, represent one of the most contentious environmental management problems in American Southwest arid lands. This review synthesizes the scattered literature about burro effects on plant communit...

grazing management plays an important role in the continuous and economicutilization of pastures. proper grazing management is a main factor for the accumulation ofplant litter which reduces soil erosion and increase the soil permeability to keep moremoisture in the soil. in current study, the effect of three different grazing intensities (low,moderate and high) along with the grazing gradient ...