Back from the Brink of Extinction

Pinzón Giant Tortoise and rare Rábida land snails expected to thrive on rat-free islands in the Galápagos.

24 July 2013

Pinzón Island in the famed Galápagos Islands, Ecuador is home to one of the greatest species recovery stories ever told. Over 100 years ago, an invasive alien species, the Black Rat (Rattus rattus), invaded the island [1] and began feeding on the defenseless eggs and hatchlings of the Pinzón Giant Tortoise (Chelonoidis ephippium). By the turn of the 20th century, the island-endemic [2] tortoise was unable to establish its next generation of tortoises. So, in 1965, conservationists, determined to save the tortoise from the rats, but limited by resources and technology, established a captive rearing program for the Extinct in the Wild [3] tortoise.

Flash forward nearly a half a century to December 2012 when a conservation partnership completed a bold project to remove rats from Pinzón Island, thus eliminating the last remaining invasive alien vertebrate species threat to the tortoise and the island’s other at-risk species. Today, heralding the recovery of the tortoise and the Pinzón ecosystem, tortoise hatchlings are emerging from native Pinzón tortoise nests on the island and the Galápagos National Park have successfully returned 118 hatchlings to their native island home.

“This is a dream come true for conservationists around the world,” said Bill Waldman, Chief Executive Officer of Island Conservation. “We owe much to our predecessors who had the foresight to preserve this unique species in captivity in anticipation of conservation tool innovations like these.” The rat removal project was conducted by Galápagos National Park assisted by partners including Island Conservation, Charles Darwin Foundation, Bell Laboratories, Inc., and The Raptor Center of the University of Minnesota.


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The Pinzón Island project is part of a much larger effort to restore this and other key Galápagos Island ecosystems to protect native plants and animals. Similar stories, starring other threatened species returning from the brink of extinction, are unfolding on islands throughout the archipelago.

Nearby Rábida Island is home to two island-endemic Rábida land snail species (Naesiotus rabidensis and Naesiotusjervisensis). However, due to invasive rats on the island, the snails were last seen and recorded in 1905-1906 by a California Academy of Sciences expedition.

For over 100 years, no live specimens were observed or recorded – until last year. In 2012, as the partnership confirmed the successful removal of rats, a surprising discovery was made by Christine Parent, PhD, from University of California Berkeley. Parent found live specimens of an endemic Rábida land snail species previously presumed to have gone extinct. “With the removal of introduced rats on Rábida and other islands, endemic land snail populations are expected to grow and recover from past predation pressure,” said Parent.

“This is astounding,” said Waldman. “We set out to trial our new partnership and conservation tools on Rábida. We expected the project to benefit Darwin’s finches and other island-endemic species. But we didn’t anticipate the re-emergence of previously thought extinct species—now safe due to the absence of rats. This underscores the importance and urgency of removing invasive alien species from islands.”

These amazing stories of species brought back from presumed extinction sets the stage for the partnership’s next major endeavor—removing multiple invasive alien species from Floreana Island.

Floreana Island is one of the largest, most complex invasive species removal projects to date. The partnership will extend to include the island’s community. While invasive feral goats have been successfully removed from this island, Black Rats, House Mice (Mus musculus), and six other invasive alien species remain and threaten the island’s rich biodiversity.

The island hosts a wealth of plants, seabirds, land birds, and wildlife including 56 IUCN [4]Red Listed species. Among them are three Critically Endangered [5] birds: Galápagos Petrel (Pterodroma phaeopygia); Medium Tree-finch (Camarhynchus pauper); and the Floreana Mockingbird (Mimus trifasciatus) whose range has been restricted to a couple of islets that are free of invasive predators.

“Bringing species back from the brink of extinction is the dream of every conservationist. But we are not resting on our laurels. Our partnership is eager to take on this challenge, and make the island safe again for the Floreana Mockingbird” Waldman said. “Who knows what other surprising species recovery success stories we may be able to tell in a few years.” The project is in the planning phase with implementation anticipated in 2015.

The Pinzón and Rábida restoration efforts were funded by Galápagos National Park, The Leona M. and Harry B. Helmsley Charitable Trust, the David and Lucile Packard Foundation, Bell Laboratories, Inc., Galápagos Conservancy, University of Minnesota, and other valued philanthropic partners.

 


[1] First recorded in 1891 but suspected to have been introduced as a result of human ship activity in the 1700s.
[2] Found only here and nowhere else in the world.
[3] From the International Union for the Conservation of Natures’ Red List of Threatened Species http://www.iucnredlist.org/
[4] International Union for the Conservation of Natures’ Red List of Threatened Species http://www.iucnredlist.org/
[5] Ibid

Contact:
Heath Packard, Island Conservation, heath.packard@islandconservation.org
Christine Parent, University of California, Berkeley, ceparent@berkeley.edu

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