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Invasive Ants Eradicated from Tiritiri Island

Ants are often an unwelcome pest species, particularly on islands, and so its great news this week that one of the world’s worst invasive ant species – the Argentine ant, has been successfully eradicated from Tiritiri Island. Argentine ants were first discovered on Tiritiri Island in 2000, and immediately were targeted for potential eradication given their predicted severe impacts on this scientific reserve. After many years of annually reducing the population by 99%, an incredibly successful control program but still 1% short of total eradication, scientists from the New Zealand Department of Conservation continued to refine their methodologies until it has now been three years since Argentine ants were last recorded on the island.

Tiritiri Matangi after 25 years of restoration
Tiritiri Matangi after 25 years of restoration

Whereas eradications of invasive mammals is now a common and powerful conservation tool, complete eradications of other taxa has remained elusive. The successful eradication of invasive ants from Tiritiri is one of a growing number of successful ant eradications recently documented in a review of ant eradications around the world. In fact there have been over 300 ant eradications attempts around the world, and about half have been successful. This is important as invasive ants can have severe impacts on ecosystems, attacking species many times their size, such as seabirds in Hawaii.

Argentine ants
Argentine ants, Linepithema humile (Photo by Lek Khauv)

These advances in ant eradications have all been underpinned by the same rigorous science, and adaptive management, which have led to the great success in rodent and other invasive mammal eradications around the world. They’ve also been supported by charismatic companions such as Rhys-Jones – an ant detection dog. Similar advances are also being made in eradication of invasive bird species from islands in the Seychelles, and demonstrate a broadening of the conservation toolkit available for protection of and restoration of biodiversity.

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