What is an invasive species?

Most non-native species do not cause problems and some economically important species are not native to the island of Ireland. The focus of Invasive Species Ireland is on invasive 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.

Definitions for terms relating to invasive species that are used by Invasive Species Ireland can be found on the website of the Convention on Biological Diversity.

How do invasive species get here and where do they come from?

 

Our activities are the main cause of the arrival of invasive species. Many species are deliberately released, like species of fish for angling. Others have escaped from our gardens and farms like the American mink and giant rhubarb. Some arrive as hitch hikers and stowaways with imported goods or other species such as the the New Zealand flatworm.

Some facts from The Secretariat of the CBD

  1. Since the 17th century invasive species have contributed to nearly 40% of all animal extinctions for which the cause is known.
  2. Annual environmental losses caused by introduced pests in the United States, United Kingdom, Australia, South Africa, India and Brazil have been calculated at over US$ 100 billion.
  3. Invasive species can transform the structure and species composition of ecosystems by repressing or excluding native species.
  4. Because invasive species are often one of a whole suite of factors affecting particular sites or ecosystems, it is not always easy to determine the proportion of the impact that can be attributed to them.

Learn more