structural:scholar_edition, stylistic:style_transfer
Naturalized species

Many other species have become naturalized outside the Americas after having been introduced by people, especially in Australia, Hawaii, and the Mediterranean region. In Australia, species of Opuntia, particularly Opuntia stricta, were introduced in the 19th century for use as natural agricultural fences and in an attempt to establish a cochineal industry. They rapidly became a major weed problem, but are now controlled by biological agents, particularly the moth Cactoblastis cactorum. The weed potential of Opuntia species in Australia continues however, leading to all opuntioid cacti except O. ficus-indica being declared Weeds of National Significance by the Australian Weeds Committee in April 2012.

The Arabian Peninsula has a wide variety of ever-increasing, introduced cactus populations. Some of these are cultivated, some are escapes from cultivation, and some are invasives that are presumed to be ornamental escapes.