Rats invasion tackled on small islands [1]
Saturday, May 28, 2016 - 13:02
A project to remove invasive rats from two Tongan islands, Malinoa and Motutapu, off Tongatapu, is proving to be successful with signs that native plants are recovering along with bird life and marine animals.
Island Conservation Project Director, Mr Richard Griffiths said that invasive vertebrates such as rats are a major threat to the biodiversity of the Pacific.
“With the positive findings of the rat eradication on Malinoa and Motutapu, we are excited to report that this program is already being replicated this month on two additional islands – Fangasito and Luahiapo in the Vava’u Island Group.
“We are delighted with this result and very pleased to see the motivation within Tonga and other Pacific islands to restore more islands,” he said.
The project was jointly launched in August 2015 and led by the Government of Tonga, the Secretariat of the Pacific Regional Environment Programme (SPREP) and the Island Conservation with participants from Kiribati, the Marshall Islands, Tonga, and Wallis et Futuna.
The islands were assessed by completing day and night surveys for rats and rat sign, and by checking rat traps set overnight. There was an increase of birds such as the Wattled Honeyeater or Fuleheu and Polynesian Starlings or Misi and it was noted that the Black-naped Terns were also nesting with eggs intact on both islands.
Many ghost crabs were observed during beach surveys and an abundance of fruit and flowers, normally eaten by rats, were seen.
Rats eat everything
Invasive rats eat everything, disrupting the existing ecological balance. By removing them, animals such as seabirds benefit as they provide an important source of nutrients for the islands, which feed the forests where other native plants and animals live.
Mr Viliami Hakaumotu, Invasive Species Coordinator of Tonga, said that Tonga was able to continue with the conservation of smaller islands.
“Tonga can do this. With what we have learned and the skills we now have we can protect our smaller but important islands and their biodiversity from the impacts of rats,”
“It is anticipated that our current work on two islands in the Vava'u group will be similarly successful and provide protection to the biodiversity of these important islands which are also important nesting sites for the critically endangered hawksbill and green turtles,” he said.
Mr David Moverley, Invasive Species Adviser of SPREP, said that it was important for Pacific countries to have the capacity to manage invasive species.
“This project is aimed at facilitating countries to succeed in meeting meaningful conservation goals, eventually on their own accord in bite size chunks.”
Non-native and invasive mammals were introduced by humans (accidentally or intentionally to ninety percent of the world’s island archipelagos, posing biodiversity challenges and opportunities. Although islands occupy less than 6% of Earth’s land area, they are home to 15% of land-dwelling species. Islands have recorded 61% of extinctions caused mainly by invasive species and according to the International Union for Conservation of Nature (IUCN), 37% of critically endangered species are found on islands.
Rodents have been successfully removed from over 500 islands world-wide and a recent study by Island Conservation states that there are major benefits to biodiversity when invasive mammals are removed from islands.
Tonga is part of this global island restoration movement.