The effects of cattle on biodiversity in Australia’s tropical savannas
Cattle grazing is the dominant land-use across the topical savannas of northern Australia. In most areas grazing is relatively low intensity, and although grazing (by cattle and other introduced herbivores) is often identified as a threatening process for many species and communities, it is often implicitly considered to be less damaging than mismanaged fire. However, the effects of grazing on wildlife have been hard to quantify because grazing is so ubiquitous across the savannas, even on conservation land.
In this study, we monitored the response of fauna after fencing and then destocking a 80,000 ha area within Mornington Wildlife Sanctuary, in the Central Kimberley. We set up permanent monitoring sites in four key habitats, and replicated these sites in matched habitats outside the stock exclusion area. Mammal and reptile species diversity and abundance increased rapidly after stock removal within the destocked area, but not at the sites that continued to carry stock. These results indicate that land managers may have underestimated the impact of grazing on biodiversity, particularly where it interacts with other threatening processes like mismanaged fire.