Feral olives (Olea europaea) as future woody weeds in Australia:: a review

Olives (Olea europaea ssp. europaea), dispersed from 19th century orchards in the Adelaide area, have become established in remnant bushland as a major environmental weed. Recent expansion of the Australian olive industry has resulted in the widespread planting of olive orchards in South Australia, Victoria, New South Wales, Western Australia, Queensland and parts of Tasmania. This paper reviews the literature on the activity of vertebrate (principally avian) olive predators and their potential as vectors for spreading this plant into Australian remnant bushland. The effects of feralisation on the olive plant, which enhances its capacity for dispersal as a weed, place wider areas of south-eastern Australia at risk. A number of approaches for the control of olives as woody weeds are addressed. Proponents of new agricultural crops have moral and environmental obligations to assess the weed potential of these crops.