Can intensification of temperate Australian livestock production systems save land for native biodiversity?

Abstract

Land use change associated with agriculture is arguably the greatest threat to global biodiversity. There is a need to develop management strategies and policies that meet conservation and agricultural objectives. One approach argued to have merit is intensification within productive parts of the landscape to allow increased land saving for conservation of biodiversity. To date there has been little empirical examination of this hypothesis. Livestock production has been the dominant land use across southern Australia for the last 100–200 years. This has contributed to biodiversity loss and other environmental issues associated with removal of native perennial vegetation. Livestock producers are under increasing pressure to maintain farm profits and it is argued that intensification through fertiliser application can increase profitability and allow more land to be set-aside for conservation management. We examined relationships between native vegetation composition and past and current farm management and combined this with assessments of current productivity and potential for intensification using either fertiliser application or changes in grazing management. Intensive management associated with phosphate fertiliser application results in exponential declines in native plant diversity, although intermediate levels of livestock grazing often have little impact on plant diversity when nutrient levels are low. Options for future intensification, via fertiliser application, often coincide with areas of high native plant diversity. Small set-asides, off-set by intensification using fertiliser application, are only affordable on farms currently managing below potential carrying capacity. These farms are often those that support extensive areas of native vegetation. At both the paddock and farm scale, increasing productivity via fertiliser application is likely to require intensification on even more land and could come at a cost to biodiversity. In contrast, improving grazing management across broad scales is likely to result in enhanced profitability and could also benefit native vegetation. Extensive management may be necessary to maintain biodiversity and prevent further long-term degradation of the resource base.