What is an Invasive Alien Species

Invasive species are species that have been introduced (deliberately or accidentally) by humans and have a negative impact on the economy, wildlife or habitats of Ireland and Northern Ireland. After habitat loss, invasive species are the second biggest threat to biodiversity worldwide, and the biggest threat on islands.


Management Control

Keep an eye out for Invasive Alien Species (IAS) in your area and record sightings with the Centre for Environmental Data and Recording.  View our downloadable guides below to help you identify invasive species that may occur in your local patch.  Recording this data is vital to help limit the amount or stop the spread completely.  Species such as the Asian Hornet or the Oak Processionary Moth have been recorded in parts of England and just recently in the island of Ireland, so vigilance is essential.

A Widely Spread Invasive Species is a species that is on the Species of Union Concern list and is considered established and widely spread in Northern Ireland.  There are 11 Widely Spread Species in Northern Ireland and their associated management measures are listed on the Invasive Species NI website.

One species of concern is Japanese Knotweed and information on how to manage and control the spread if also available on the Invasive Alien Species NI website.  The legislation in relation to Japanese Knotweed states that:

Human activities are the main cause of the arrival of invasive species.  Many species are deliberately released whilst others have escaped from our gardens and farms like the American mink and giant rhubarb.  Some arrive as hitchhikers and stowaways with imported goods like the New Zealand flatworm!

For further species information and identification visit Invasive Species Ireland or Non Native Species Secretariat.



Under article 15 of the Wildlife (Northern Ireland) Order 1985, it is an offence to plant or otherwise cause to grow in the wild, Japanese Knotweed or any other invasive plant listed in Part II of Schedule 9 to that Order.  There is no legal obligation to remove Japanese Knotweed from your land or report it to the regulators, however, the presence of the weed may result in civil liabilities.

Nor does the Wildlife (NI) Order 1985 include offences for the natural spread of an Invasive Species from one area to another. But there is perhaps a community expectation within society that owners of the property and land look after such assets responsibly.


File Type Size Date
Asian Hornet Flyer pdf 1 MB 23rd May 2021
Giant Hogweed Flyer pdf 7 MB 23rd May 2021
Himalayan Balsam Flyer pdf 5 MB 23rd May 2021
Invasive Alien Species ID cards pdf 801 KB 23rd May 2021
Invasive Alien Species Plant identification pdf 5 MB 23rd May 2021
Japanese Knotweed Flyer pdf 5 MB 23rd May 2021