title: Long-term monitoring of feral genetically modified herbicide-tolerant Brassica napus populations around unloading Japanese ports.
abstract: Genetically modified, herbicide-tolerant (GMHT) Brassica napus plants originating from seed spill have recently been found along roadsides leading from Japanese ports that unload oilseed rape. Such introductions have potential biodiversity effects (as defined by the Cartagena Protocol): these include replacement of native elements in the biota through competitive suppression or hybridization. We conducted surveys in the period 2006-2011 to assess such threats. We examined shifts in the population distribution and occurrence of GMHT plants in 1,029 volunteer introduced assemblages of B. napus, 1,169 of B. juncea, and 184 of B. rapa around 12 ports. GMHT B. napus was found around 10 of 12 ports, but its proportion in the populations varied greatly by year and location. Over the survey period, the distributions of a pure non-GMHT population around Tobata and a pure GMHT population around Hakata increased significantly. However, there was no common trend of population expansion or contraction around the 12 ports. Furthermore, we found no herbicide tolerant B. juncea and B. rapa plants derived from crosses with GMHT B. napus. Therefore, GMHT B. napus is not invading native vegetation surrounding its populations and not likely to cross with congeners in Japanese environment.
authors.affiliation: Food Safety and Consumer Affairs Bureau, Ministry of Agriculture, Forestry and Fisheries of Japan , Kasumigaseki, Tokyo 100-8950 , Japan.
authors.forename: Kensuke
authors.initials: K
authors.lastname: Katsuta
authors.affiliation: Biodiversity Division, National Institute for Agro-Environmental Sciences , Tsukuba, Ibaraki 305-8604 , Japan.
authors.forename: Kazuhito
authors.initials: K
authors.lastname: Matsuo
authors.affiliation: Biodiversity Division, National Institute for Agro-Environmental Sciences , Tsukuba, Ibaraki 305-8604 , Japan.
authors.forename: Yasuyuki
authors.initials: Y
authors.lastname: Yoshimura
authors.affiliation: Faculty of Life and Environmental Sciences, University of Tsukuba , Tsukuba, Ibaraki 305-8572 , Japan.
authors.forename: Ryo
authors.initials: R
authors.lastname: Ohsawa
keywords: Brassica; ferality; genetically modified; herbicide tolerance; invasiveness; persistence; seed spillage