Open Access

Bruce Auld, Hirohiko Morita, Tomoko Nishida, Misako Ito, Peter Michael

• Japan and south eastern Australia have a large exotic flora in common, in spite of contrasting histories, physiographies and land-use patterns. There are some 187 common invading species and at least 71 of these are widespread in both locations. Some 15 widespread exotic invaders in Japan have not been recorded in Australia and a number of native Japanese plants that could be introduced as ornamentals and escape cultivation are noted. The incursion of most exotic species to Japan has been historically recent. The lack of quarantine for plants (apart from parasitic plants and plants infected with disease) coupled with large importations of wheat and soybeans from north America and contaminated grain and fodder for farm animals has led to an exponential rate of plant invasion in Japan. The apparent lack of impact of woody invading species in Japanese forests and forests margins may be due simply to the relatively short time invading species (some with long juvenile periods) have been naturalised.