Agricultural intensification, climate change and threatened biodiversity - a case study from Tasmania

Tasmania, Australia's island state, has an exceptionally diverse geo-climatic landscape that supports an incredibly diverse assemblage of floral and faunal species, including rare and threatened species, and an equally diverse agricultural structure. Unfortunately, the two phenomena largely compete for the same limited landscape space and are uncomfortable bedfellows with a consequent loss of biodiversity and ongoing threats of diminished levels of ecological services. This also conflicts with the State’s economy actively trading on an image of abundant ‘pure and natural’ environmental values for both its’ agricultural produce and a growing tourism economy. For most of the period following the Second World War, Tasmanian agriculture has been dramatically transformed through considerable diversification and intensification. This has been particularly manifest in a significant expansion of field cropping and horticulture into former forest and open grazing lands and the wide-scale replacement of native pastures with sown exotic species accompanied by irrigation and regular and high applications of chemical fertilisers. Projected climate change for Tasmania generally favours further agricultural intensification and, bolstered by an expansion of both public and private irrigation infrastructure, an expansion of intensive cropping activities in both traditional broadacre cropping regions and former grazing lands. The paper explores the implications of the projected expansion of irrigation and cropping on terrestrial biodiversity using insights from 5 regional case studies. On-farm remedial practices and appropriate conservation policy adjustments are suggested.