AUSSIE INVASION

Azores After escaping from hedges in 1 the 19th century, sweet pittosporum ( Pittosporum undulatum) now occupies 24,000 ha in the Azores, equivalent to 49 per cent of its forested area.

England An Australian barnacle ( Austro2 minius modestus) that arrived on ships decades ago thrives today in England, including in the Thames, and also on the continent. It displaces native European barnacles.

France West of Paris, in the Forest of 3 Rambouillet, drivers are warned by road signs to watch out for red-necked wallabies, the descendants of escapees from a wildlife park.

Germany Black swans that escaped from 4 captivity or were released have formed small breeding populations in Germany, Italy, Belgium and elsewhere in Europe, and Japan as well.

Zambia Africa lacks native crayfish, raising 5 questions about the impacts Australian redclaw crayfish ( Cherax quadricarinatus) are having in Lake Kariba in Zambia, and in other African wetlands.

South Africa Eucalypts are less invasive 6 than many Australian plants, but in South Africa the river red gum ( Eucalyptus camaldulensis) has spread along many watercourses.

Israel Israel is one of many countries 7 to have golden wreath wattle ( Acacia saligna) as a weed, with infestations in many places including the Judean Mountains and near Jerusalem.

India The Australian sugarcane planthop8 per ( Perkinsiella saccharicida) has become a pest in most countries that grow sugar cane, including India.

Japan The redback spider ( Latrodectus has9 seltii) is a serious concern in Japan, where it has spread across much of the country, to the concern of residents.

10 Guam The eastern dwarf tree frog or eastern sedge-frog ( Litoria fallax), is tiny, but that didn’t stop it somehow reaching Guam and thriving there.

Vanuatu Animals often undergo ‘ecological 11 release’ when they establish somewhere new, and for the green and golden bell frog

( Litoria aurea) that has included thriving in Vanuatu, which is hotter than its native

New South Wales.

New Zealand The Australian paper 12 wasp ( Polistes humilis) is one of the stinging creatures New Zealand has acquired from Australia, along with the redback and huntsman spiders.

Hawaii When it was discovered in Hawaii 13 a century ago, the common grass skink ( Lampropholis delicata) was thought to be a native reptile.

Tahiti In Tahiti, silvereyes released in the 14 1930s to colour the landscape now spread the seeds of the island’s worst weed, miconia, a South American tree that covers vast areas of damaged rainforest.

California Vedalia beetle ( Rodolia 15 cardinalis) is a welcome Australian, taken to California in 1888 to feed on cottony cushion scale, an Australian sap-sucking bug.

Chile Silver wattle ( Acacia dealbata) is 16 very weedy in Chile, but also a useful source of firewood.

Florida A common paperbark tree 17

( Melaleuca quinquefolia) can shed millions of seeds when it is killed, helping explain why it is southern Florida’s worst weed.

Jamaica After escaping from a botanic 18 garden, sweet pittosporum ( Pittosporum undulatum) spread over 1300ha of montane tropical rainforest in Jamaica, benefiting from hummingbirds that pollinate its flowers and Jamaican orioles that spread its seeds.

Argentina Trade in pot plants probably 19 explains how the blue garden flatworm ( Caenoplana coerulea) reached Argentina, one of many countries it has colonised. Brazil In the Atlantic forests of Brazil 20 the piccabeen palm ( Archontophoenix cunninghamiana) is fast becoming a weed, owing to a high seed output.

Greenland The Australian spider beetle 21 ( Ptinus tectus) can survive winters in Greenland because it lives inside kitchens in stored foods.