Invasive non-native plant and animal species are the second greatest threat to biodiversity worldwide after habitat destruction. Ireland is no exception, and many species that have newly arrived to Ireland has disrupted local ecosystems and threaten our native biodiversity. New regulations have been introduced in the European Union and transposed into Irish law, to mitigate the threat posed by invasive alien species.  There are many contenders for Ireland’s most unwanted species, but  here we have profiled 10 species which we feel are particularly unwelcome.

Giant hogweed

Giant hogweed
Giant hogweed (Heracleum mantegazzianum) is a flowering plant up to 5m tall that is native to the Caucasus, between the Caspian and Black seas. It was a popular Victorian garden 'curiosity', first introduced to Britain and then Ireland in the 19th century. The first noted escape from cultivation was in Dublin in 1902-1903, and it has since become established along river banks and other areas of damp waste ground. Single plants may grow initially, but due to the very large volume of seeds it produces it will spread rapidly in an area. It is a public health hazard due to its toxic sap which causes severe dermatitis (Photograph: Seamus Forde).