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Find it in Fermanagh – Invasive Species

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During July and August we are encouraging you to get outside in Fermanagh and discover a local species! This week for our ‘Find it in Fermanagh’ series we are raising awareness of some invasive species present in the county.

An invasive species is a species that has been introduced, either deliberately or accidentally, by humans. Invasive species have a negative impact on the economy, wildlife and other habitats. After habitat loss, invasive species are the second biggest threat to biodiversity worldwide! Invasive species can be plants, mammal and marine life. Remember – Please do not touch any invasive species, rather their presence can be reported via

Japanese Knotweed

Identification Card

Originating from Eastern Asia, Japanese Knotweed was first brought to Britain by the Victorians as an ornamental plant and a cattle feed. It has no natural enemies and out competes a number of native species. It is most commonly found in urban areas including railways, roadsides and river banks. Japanese Knotweed spreads via rhizomes or stalks and not by seed, which means when cut it can regrow. The removal of Japanese Knotweed is very difficult and involves chemical removal. If you see Japanese Knotweed growing, you should report it using the links provided below.

Himalayan Balsam

Identification Card

Another one from Eastern Asia, Himalayan Balsam was introduced by the Victorians for its attractive pink flowers and exploding seed pods, which help it to expand exponentially. It commonly occurs in damp environments including ricer banks and damp woodlands. Whilst it can be manually cut or pulled this should be done prior to the formation of its seed pods which explode at the slightest disturbance when ripe. It is an extremely competitive plant and outcompetes native species for habitats.

Grey Squirrels

Native to North America, grey squirrels were first introduced to the UK in the 19th century. They are larger than our native Red Squirrels and therefore out compete them for habitats and food within our mature woodlands. Furthermore Grey Squirrels carry the parapox virus which Red Squirrels have no immunity too. For more information about Red Squirrel Conservation in Co. Fermanagh visit Fermanagh Red Squirrel Group.

Zebra Mussels

Identification Card

The zebra mussel arrived in approx. 1994 attached to the hulls of second-hand boats imported. Originally from the Caspian and Black Sea region, the zebra mussel has a distinctive stripy shell and individuals are small, growing up to 3-4 cm in length. Unlike other freshwater mussels, the zebra mussel attaches to hard surfaces. They result in the extinction of native swan and duck mussels and they filter the water so it becomes clearer resulting in increased plant growth which impedes fishing and boat navigation. Furthermore they decrease the amount of zooplankton and food available for fish.


Identification Card

This species was first introduced to parks, gardens, and demesnes in Britain and Ireland in the 1700’s due to its distinctive attractive flowers and large dark green coloured, oval leaves. It can grow quite tall with specimens regularly attaining 8 m. Rhododendron can form very dense thickets and out-compete native plants for space and resources, especially for sunlight. 

What to do if you see an invasive species?

You can report sightings of invasive species to

Through the Aliens on the Lough project in partnership with Fermanagh and Omagh District Council Invasive Species Identification cards which can be accessed here.

If you would like a copy of the cards they can be collected from Killyvilly Council Depot or contact Heather via