ABSTRACT
At least 80 species of non-indigenous vertebrates have established wild populations in Australia, and more than 30 of these species have become pests. Direct short-term economic losses caused by these species amount to at least $420 million per year, mainly in lost agricultural production. Overgrazing and browsing by introduced herbivores also contribute to land degradation, which reduces the capacity for future productivity in many areas, but the value of this degradation has not been estimated. In addition, grazing, predation, and competition by non-indigenous vertebrates are recognised as major threats to many endangered native species and communities, and these costs have not been quantified either.
