Invasive aquatic plants in Japan
In Japan, alien aquatic plants have been introduced since the 1800s, for example Cabomba caroliniana, Egeria densa, Eichhornia crassipes, Iris pseudoacorus, Myriophyllum aquaticum, and M. brasiliense. In the past few decades, more and more alien aquatic plants have been newly introduced and commercially sold by various routes due to massive demand for aquarium and gardening. Amongst the more than 300 aquatic plants available on the market as aquarium plants, over 40 species are naturalized in Japan, and some of them have shown invasive behaviour. Thirty seven of these species are listed below with their families, origin and distribution in the EPPO region when available. Species are classified according to their status in Japan.
Alien species naturalized and widespread in Japan:
|
Species
|
Origin
|
Occurrence in EPPO region
|
|
Eichhornia crassipes (Pontederiaceae)
(EPPO A2 List) |
S-Am.
|
ES, IL, IT, JO, PT
|
|
Egeria densa (Hydrocharitaceae)
(EPPO List of Invasive Alien Plants)
|
S-Am.
|
Widespread
|
|
Elodea nuttallii (Hydrocharitaceae)
(EPPO List of IAP)
|
N-Am.
|
Widespread
|
|
Iris pseudacorus (Iridaceae)
|
Eur., W Asia, N-Af.
|
Native, widespread
|
|
Paspalum distichum var. distichum,
P. distichum var. indutum (Poaceae) |
Neotrop.
|
CY, ES (incl. Azores, Baleares, Canarias), FR (incl. Corse), GB, GR, IT (incl. Sardinia), PT (incl. Madeira), RO, TR
|
|
Landoltia punctata (Lemaneaceae)
|
SE Asia, Australia
|
ES, IL
|
|
Wolffia globosa (Lemnaceae)
|
Asia, N ; S Am.
|
/
|
|
Cabomba caroliniana (Cabombaceae)
EPPO List of IAP |
Am.
|
BE, FR, GB, HU, NL
|
|
Nasturtium officinale (Brassicaceae)
|
Eur., Asia, N-Africa
|
Native, widespread
|
|
Myriophyllum aquaticum (Haloragaceae)
EPPO List of IAP |
S-Am.
|
Widespread
|
|
Nymphea spp. (Nymphaeaceae)
|
/
|
/
|
Species which have increased their distribution in Japan rapidly in recent years:
|
Species
|
Origin
|
Occurrence in EPPO region
|
|
Azolla spp. (Salviniaceae)
|
/
|
/
|
|
Pistia stratiotes (Araceae) EPPO Alert List
|
S-Am.
|
Canarias (ES)
|
|
Alternanthera philoxeroides (Amaranthaceae) EPPO Alert List
|
S-Am.
|
FR, IT
|
|
Veronica anagallis-aquatica (Scrophulariaceae)
|
Eur., Asia, Africa, S-Am.
|
Native, widespread
|
|
Gymnocoronis spilanthoides (Asteraceae)
|
S-Am.
|
/
|
|
Hydrocotyle verticillata var. triradiata (Apiaceae)
|
S-Am.
|
ES
|
|
Hydrocotyle ranunculoides (Apiaceae)
EPPO A2 List |
Am.
|
BE, DE, FR, GB, IE, IT, NL
|
|
Ludwigia repens (Onagraceae)
|
Am.
|
/
|
Species which have a limited distribution in Japan:
|
Species
|
Origin
|
Occurrence in EPPO region
|
|
Sagittaria graminea (Alismataceae)
|
Am.
|
/
|
|
Vallisneria gigantea (Hydrocharitaceae)
|
Am., Asia
|
Widespread
|
|
Heteranthera limosa (Pontederiaceae)
|
Am.
|
ES, IT (incl. Sardinia), FR, PT
|
|
Bacopa rotundifolia (Scrophulariaceae)
|
N-Am.
|
?
|
|
Lemna gibba (Lemnaceae)
|
Cosmop.
|
Native, widespread
|
|
Trapa natans var. bispinosa (Trapaceae)
|
Africa, Asia
|
/
|
|
Utricularia gibba (Lentibulariaceae)
|
N ; C Am.
|
ES, LU
|
|
Utricularia inflata (Lentibulariaceae)
|
N-Am.
|
/
|
Species which have been observed in the wild but did not naturalize so far:
|
Species
|
Origin
|
Occurrence in EPPO region
|
|
Salvinia molesta (Salviniaceae)
EPPO Alert List |
S-Am.
|
IT, PT
|
|
Limnobium laevigatum (Hydrocharitaceae)
|
Am.
|
/
|
|
Eichhornia azurea (Pontederiaceae)
|
S-Am.
|
/
|
|
Pontederia cordata (Pontederiaceae)
|
Am.
|
ES, FR, GB, IE, IT, NL
|
|
Thalia dealbata (Marantaceae)
|
N-Am.
|
/
|
|
Heteranthera zosterifolia (Pontederiaceae)
|
S-Am.
|
/
|
|
Lagarosiphon major (Hydrocharitaceae)
EPPO List of IAP |
Africa
|
Widespread
|
|
Hydrocleis nymphoides (Limnocharitaceae)
|
S-Am.
|
/
|
|
Neptunia oleracea (Fabaceae)
|
Af., Asia, Am.
|
/
|
|
Nymphoides aquatica (Menyanthaceae)
|
N-Am.
|
/
|
Sources
Kadono Y (2004) alien aquatic plants naturalized in Japan: history and present status. Global environment research 8(2), 163-169. http://www.airies.or.jp/publication/ger/pdf/08-02-07.pdf
A list of naturalized alien plants in Japan can be found in:
Mito T, Uesugi T (2004) Invasive Alien Species in Japan: The Status Quo and the New Regulation for Prevention of their Adverse Effects. Global Environmental Research 8(2), 171-191. http://www.airies.or.jp/publication/ger/pdf/08-02-08.pdf