galapagos
CNH Tours - Cultural and Natural Heritage Tours Galapagos
Wednesday January 19, 2011
Largest rat eradication in South America - ever!
(from the Galapagos National Park News service)
The Galapagos National Park Service, with the support of the
organization Island Conservation, Charles Darwin Foundation, The
Raptor Center at the University of Minnesota, Durell Wildlife Trust
and Bell Laboratories, began implementing a massive ecological
restoration project by removing introduced rodents.
This ambitious plan, developed for the first time in South
America, in a first phase, focuses on the total eradication of
introduced rats and mice on small and medium-sized islands of the
Galapagos. In a pilot project in 2008, all rodents were
successfully eradicated from the 184 ha North Seymour island, a
popular visitor site where frigates can be seen nesting, and large
land iguana's roam.
Next on the Park's target list are Rabida, Bartolome, Sombrero
Chino, North Plaza islands (all visitors sites).
Successfully getting at every last rat and mouse on a large island
is not easy. Poisoned baits will be distributed
aerially via a helicopter mounted mechanical bait dispersal
mechanism. Lessons learned in the pilot project will be
applied - such as distributing baits at 7 day intervals, to ensure
that rats too young to consume them in the first dispersal, are old
enough to do so at the second dispersal.
The helicopter is equipped with a high precision GPS, allowing the
pilot adequate control of the flight and therefore ensuring that no
square metre of an island is left out.
Before applying the product, as part of this plan, risk analysis
was performed on non-target species such as hawks, finches and
mockingbirds, to determine possible effect on these
species. The Park learned that the species at highest
risk was the hawk, as it may capture and feed on rodents that have
consumed the bait. Adequate measures to avoid this
eventuality were needed. These consisted of live
capturing hawks, and keeping them in cages specifically designed to
hold them under optimal conditions, during the rat baiting
periods.
Rodents in Galapagos
- In the Galapagos there are 3 types of introduced rodents: the black rat, Norway rat and house mouse.
- Rodents have caused adverse effects on reproduction of tortoises, iguanas, land and sea birds, especially on the Galapagos petrel, which nests in the wetlands of the larger islands.
- Unless rodents are completely exterminated, their negative effects can never be sufficiently controlled, and vulnerable Galapagos wildlife will remain at risk.
Because native animals of Galapagos arrived only by successfully crossing 1,000 km of open ocean, very few mammals are native to the islands. Only 2 bat species and one native "rice rat" .