Maximizing retention of native biodiversity in Australian agricultural landscapes-The 10:20:40:30 guidelines

The negative impacts of agriculture on biodiversity increase as production intensifies. In Australia some 465 million hectares support agricultural production, with intensity varying according to the productive potential of the land, and over time, with changes in technology, markets and societal goals. In the context of ongoing change in Australian landscapes, we develop broad guidelines for balancing land use intensity with retention of native biodiversity. We categorize agricultural land uses into four broad levels of intensity based on anthropogenic disturbance and inputs, and consider the resources each offers towards persistence of different types of organisms. We conclude that persistence of Australian native species under increasing agricultural intensity is determined more by habitat specialization and mobility than by taxonomic grouping. Generalizing from land use principles previously proposed for grassy eucalypt woodlands, we suggest that retention of native biodiversity can be maximized in production landscapes that have: (i) a minimum 10% core natural vegetation that is managed for biodiversity conservation; (ii) a minimum additional 20% natural vegetation that is managed under low intensity production systems; (iii) a maximum of 30% allocated to intensive production systems; and (iv) the balance between natural vegetation (min 30%) and intensive production (max 30%) allocated to moderate intensity production systems. While production landscapes in the pastoral and high rainfall zones of Australia could potentially meet most of these guidelines, very few in the wheat-sheep zone do. Modifying farms in the wheat-sheep zone to meet the guidelines is technically feasible, but not economically attractive at present. However policy and markets that support bio-sequestration of carbon could bring about land use change that, if appropriately targeted, could significantly improve retention of native biodiversity in Australian agricultural landscapes. (C) 2012 Elsevier B.V. All rights reserved.