100 of the World’s Worst Invasive Alien Species

This list was created by the Invasive Species Specialist Group (ISSG) of the World Conservation Union (IUCN). Species were selected using two criteria: their serious impact on biological diversity and/or human activities, and their illustration of important issues of biological invasion. To ensure a wide variety of examples, only one species from each genus was selected. Absence from the list does not imply that a species poses a lesser threat.

SPECIES ENGLISH NAME TAXONOMIC GROUP LU-LISTS
Banana bunchy top virus banana bunchy top virus Microorganism  
Plasmodium relictum avian malaria Microorganism  
Rinderpest virus rinderpest virus Microorganism  
Aphanomyces astaci crayfish plague Macrofungi  
Batrachochytrium dendrobatidis frog chytrid fungus Macrofungi  
Cryphonectria parasitica chestnut blight Macrofungi  
Ophiostoma ulmi Dutch elm disease Macrofungi  
Phytophthora cinnamomi phytophthora root rot Macrofungi  
Caulerpa taxifolia caulerpa seaweed Aquatic plant  
Eichhornia crassipes water hyacinth Aquatic plant  
Spartina anglica common cord-grass Aquatic plant  
Undaria pinnatifida wakame seaweed Aquatic plant  
Acacia mearnsii black wattle Land plant  
Ardisia elliptica shoebutton ardisia Land plant  
Arundo donax giant reed Land plant  
Cecropia peltata pumpwood Land plant  
Chromolaena odorata Siam weed Land plant  
Cinchona pubescens quinine tree Land plant  
Clidemia hirta Koster’s curse Land plant  
Euphorbia esula leafy spurge Land plant  
Fallopia japonica Japanese knotweed Land plant A3
Hedychium gardnerianum Kahili ginger Land plant  
Hiptage benghalensis hiptage Land plant  
Imperata cylindrica cogon grass Land plant  
Lantana camara lantana Land plant  
Leucaena leucocephala leucaena Land plant  
Ligustrum robustum privet Land plant  
Lythrum salicaria purple loosestrife Land plant  
Melaleuca quinquenervia melaleuca Land plant  
Miconia calvescens miconia Land plant  
Mikania micrantha mile-a-minute weed Land plant  
Mimosa pigra mimosa Land plant  
Myrica faya fire tree Land plant  
Opuntia stricta erect pricklypear Land plant  
Pinus pinaster cluster pine Land plant  
Prosopis glandulosa mesquite Land plant  
Psidium cattleianum strawberry guava Land plant  
Pueraria montana var. lobata kudzu Land plant  
Rubus ellipticus yellow Himalayan raspberry Land plant  
Schinus terebinthifolius Brazilian pepper tree Land plant  
Spathodea campanulata African tulip tree Land plant  
Sphagneticola trilobata wedelia Land plant  
Tamarix ramosissima tamarisk Land plant  
Ulex europaeus gorse Land plant  
Asterias amurensis Northern Pacific seastar Aquatic invertebrate  
Carcinus maenas green crab Aquatic invertebrate  
Cercopagis pengoi fish hook flea Aquatic invertebrate  
Dreissena polymorpha zebra mussel Aquatic invertebrate A2
Eriocheir sinensis Chinese mitten crab Aquatic invertebrate C0
Mnemiopsis leidyi comb jelly Aquatic invertebrate  
Mytilus galloprovincialis Mediterranean mussel Aquatic invertebrate  
Pomacea canaliculata golden apple snail Aquatic invertebrate  
Potamocorbula amurensis marine clam Aquatic invertebrate  
Achatina fulica giant African snail Land invertebrate  
Aedes albopictus Asian tiger mosquito Land invertebrate C0
Anopheles quadrimaculatus common malaria mosquito Land invertebrate  
Anoplolepis gracilipes crazy ant Land invertebrate  
Anoplophora glabripennis Asian longhorned beetle Land invertebrate B0
Bemisia tabaci sweet potato whitefly Land invertebrate  
Cinara cupressi cypress aphid Land invertebrate  
Coptotermes formosanus shiraki Formosan subterranean termite Land invertebrate  
Euglandina rosea rosy wolf snail Land invertebrate  
Linepithema humile Argentine ant Land invertebrate C0
Lymantria dispar gypsy moth Land invertebrate  
Pheidole megacephala big-headed ant Land invertebrate  
Platydemus manokwari flatworm Land invertebrate  
Solenopsis invicta red imported fire ant Land invertebrate  
Trogoderma granarium khapra beetle Land invertebrate  
Vespula vulgaris common wasp Land invertebrate  
Wasmannia auropunctata little fire ant Land invertebrate  
Bufo marinus cane toad Amphibian  
Eleutherodactylus coqui Caribbean tree frog Amphibian  
Rana catesbeiana bullfrog Amphibian A0
Clarias batrachus walking catfish Fish  
Cyprinus carpio carp Fish  
Gambusia affinis Western mosquito fish Fish  
Lates niloticus Nile perch Fish  
Micropterus salmoides large-mouth bass Fish  
Oncorhynchus mykiss rainbow trout Fish C2
Oreochromis mossambicus Mozambique tilapia Fish  
Salmo trutta brown trout Fish  
Acridotheres tristis Indian myna bird Bird  
Pycnonotus cafer red-vented bulbul Bird  
Sturnus vulgaris starling Bird  
Boiga irregularis brown tree snake Reptile  
Trachemys scripta red-eared slider Reptile C1
Capra hircus goat Mammal  
Cervus elaphus red deer Mammal  
Felis catus domestic cat Mammal  
Herpestes javanicus small Indian mongoose Mammal  
Macaca fascicularis macaque monkey Mammal  
Mus musculus mouse Mammal  
Mustela erminea stoat Mammal  
Myocastor coypus nutria Mammal C0
Oryctolagus cuniculus rabbit Mammal  
Rattus rattus ship rat Mammal  
Sciurus carolinensis grey squirrel Mammal  
Sus scrofa pig Mammal  
Trichosurus vulpecula brushtail possum Mammal  
Vulpes vulpes red fox Mammal  

References

Lowe S., Browne M., Boudjelas S., De Poorter M. (2000) 100 of the World’s Worst Invasive Alien Species – A selection from the Global Invasive Species Database. Published by The Invasive Species Specialist Group (ISSG) a specialist group of the Species Survival Commission (SSC) of the World Conservation Union (IUCN), 12pp. First published as special lift-out in Aliens 12, December 2000. Updated and reprinted version: November 2004. [PDF]

 Page content last updated on 2021-03-27. Last proofread by Caroline Grounds on 2019-11-11.