ABSTRACT
Large areas of northern Australia occur as eucalypt woodlands where the major form of land use for 100 years or more has been beef production. The native grazing pastures of the dry tropics are dominated by tall perennial grasses such as Heteropogan contortis and Bothriochloa bladhii. For improved grazing and increased beef production, such pastures are often oversown with tropical legumes such as Stylosanthes humilis or S. sundaica. Dairy pastures require high application of inorganic nitrogen fertiliser to secure good production of forage and high milk yields. The rangelands of the tropical north, like those of other regions of Australia have undergone extensive anthropogenic land cover changes. Such changes on what is already an extremely fragile system strongly influenced by southern oscillation cycles and extremes of temperature and rainfall have in their turn significantly impacted on regional and even global climate.
