Potential of current perennial plant-based farming systems to deliver salinity management outcomes and improve prospects for native biodiversity: a review

Abstract

Existing perennial plant-based farming systems are examined within 4 climatic zones in southern Australia (western winter rainfall, south-eastern low to medium rainfall, south-eastern high rainfall and northern summer rainfall) to assess their potential to improve the management of dryland salinity. If profit is to be the primary driver of adoption, it appears that the available options (lucerne and other perennial pastures, farm forestry, saltland pastures and forage shrubs) will fall short of existing hydrological targets with the exception of the higher rainfall zones. In the 3 eastern zones, the need to preserve fresh water flows to permanent river systems places limitations on the use of perennial plants, while the higher proportion of regional groundwater flow systems increases response times and heightens the need for regional coordination of effort. In the western zone, the prevalence of local and intermediate ground water flow systems increases effectiveness of individual action. Research into new perennial land use systems has been characterised by an emphasis on water use over profit resulting from poor dialogue between paddock, farm and catchment scales. Exploring the water use implications of land use systems that are potentially viable at farm scale is a more promising approach than focusing on the opportunity cost of catchment scale intervention. Perennial plant-based farming systems present both threats and opportunities to native biodiversity. The major threat is the introduction of new environmental weeds. The opportunities are potential improvements in vegetative cover, food sources and habitat for the native biota, but only where nature conservation goals can influence the structural complexity, composition and location of new land use systems.