An Economic Approach to Plant Introduction Decisions: The case of plant-based solutions to salinity

Abstract

Invasive plants and dryland salinity both impose considerable costs on the Australian environment and agriculture. Expectations are for these costs to increase still further because both result from dynamic, and sometimes lengthy, processes. A range of exotic pasture plant species has been identified as having the potential to reduce dryland salinity if introduced to Australian farming systems. With this opportunity however comes the potential for these new plants to become invasive (i.e. weeds) and thus add to the already high annual costs of introduced plants. How do we decide whether to introduce the new pasture plants or not? Current decision processes employ a precautionary approach that favours the exclusion of new plants from Australia through consideration of potential costs but not benefits. As the potential gains and costs from the new pasture plants may both be high, an alternative decision framework is needed. This thesis presents an economic approach where introductions are allowed when they offer positive contributions to society's welfare. The approach has been applied to the decision to introduce new varieties of birdsfoot trefoil ('Lotus corniculatus' L.) to the Kings Plain Subcatchment within the Border Rivers Catchment of northern New South Wales. ... The study offers a balanced and improved means of determining if new plants should be introduced and policy approaches to this decision, when costs and benefits, including externalities, result from dynamic and uncertain natural processes.