An impact oscillator is a non-smooth dynamical system with discontinuous state jumps whose dynamical behavior illustrates a variety of nonlinear phenomena including a grazing bifurcation. This specific phenomenon is difficult to analyze because it coincides with an infinite stretching of the phase space in the neighborhood of the grazing orbit, resulting in the well-known problem of the square-...

Resilience-based frameworks, founded upon the existence of multiple attractors and regime shifts, have long been applied to complex dynamics of semiarid systems. Utilizing seed addition tests in experimental plantings along grazing gradients, we applied an increase-when-rare criterion to identify bidirectional (states can invade each other) and directional (only one state can invade) transition...

Advances in global positioning system (GPS) technology have dramatically enhanced the ability to track and study distributions of free-ranging livestock. Understanding factors controlling the distribution of free-ranging livestock requires the ability to assess when and where they are foraging. For four years (2008-2011), we periodically collected GPS and activity sensor data together with dire...

Profitable livestock production from forages largely depends on efficiency of converting forages into products. Efficient grazing management systems require an understanding of the roles of system components. However, experimentation should be conducted with regard to the system as a whole rather than on the systems components in isolation. This may necessitate development of computer models. T...

Grazing lawns are a distinct grassland community type, characterised by short-stature and with their persistence and spread promoted by grazing. In Africa, they reveal a long co-evolutionary history of grasses and large mammal grazers. The attractiveness to grazers of a low-biomass sward lies in the relatively high quality of forage, largely due to the low proportion of stem material in the swa...

A 6-year study was conducted in tallgrass prairie to assess the effects of grazing management (cattle stocking densities and grazing systems) on plant community composition and diversity. Treatments included sites grazed season-long (May to October) at 3 stocking densities (3.8, 2.8, and 1.8 hectares per animal unit), ungrazed control sites, and sites under a late-season rest rotation grazing s...

The effects of grazing and nutrients on epiphyte biomass in seagrass beds have received much attention, yet less is known about effects on other metrics of epiphyte growth dynamics, such as epiphyte productivity and biomass turnover rates. To help address this gap, we present here a number of mesocosm experiments in which we manipulate grazer presence and nutrient concentrations under initially...

Nigeria is one of the most malnourished and hunger ridden in the league of developing countries; according to reports of Food and Agricultural Organization (FAO) of United Nations estimated daily animal protein intake for developing countries averaged at 4.5 g/head/day at the beginning of this century which has hardly risen to 10 g/head/day into the second decade of the century in Nigeria. This...

Studies across 5 yr involving 938 British-breed crossbred cattle (372 heifers, 566 steers) were used to evaluate the effects of grazing alternate summer and fall forages on slaughter breakeven cost of various beef production systems. Grazed summer forage combinations included 1) continuous brome, 2)brome and warm-season grasses, 3) brome and alfalfa or sudangrass, 4) brome and a monoculture of ...