September 13, 2017
The Galapagos National Park Directorate (GNPD) in collaboration with Galapagos Conservancy (GC), as part of the Giant Tortoise Restoration Initiative (GTRI), has initiated a breeding program to bring back the extinct Floreana tortoise (Chelonoidis niger, recently called C. elephantopus). This program is based on a decade of exploration and genetic analysis of saddleback tortoises found on Wolf Volcano, the northernmost volcano of Isabela Island.
A GTRI expedition to Wolf Volcano in November 2015, coordinated by the GNPD and GC, was carried out to locate and sample as many saddleback tortoises as possible, and to transfer a subset of those tortoises to the Fausto Llerena Tortoise Center on Santa Cruz Island. The search was aimed at identifying tortoises with ancestry from both Floreana and Pinta Islands, two species of saddleback tortoises that went extinct on their home islands.
Genetic analysis of 150 saddleback tortoises (144 from Wolf Volcano and six already in captivity) identified 127 with varying levels of ancestry from the Floreana tortoise. During the expedition, 32 tortoises were transported from Wolf to the Tortoise Center; of these, 19 were found to have Floreana ancestry. Unfortunately, no tortoises with Pinta tortoise ancestry were identified. A group of researchers led by investigators from Yale University reported these results in the journal Scientific Reports – Nature on September 13, 2017.
“This is one of the most exciting advances of the Giant Tortoise Restoration Initiative. To restore, even partially, the extinct Floreana tortoise population was unthinkable only a few years ago. And now we will live to see it happen,” commented Dr. Linda Cayot, Science Advisor for Galapagos Conservancy and coordinator of the GTRI.
Based on preliminary results provided by Yale University researchers to the GTRI, four breeding groups of tortoises, each with three females and two males, were established in March 2017. In approximately five years, offspring from these breeding groups will begin to be released on Floreana Island.
The Floreana tortoise went extinct on its home island approximately 150 years ago due to exploitation by whalers and other mariners for food and hunting by the first settlers in the 18th and 19th centuries. Whether to lighten their load for the journey home or to make additional room for whale oil, mariners dropped a large number of tortoises from other islands at Banks Bay, at the base of Wolf Volcano. Throughout the last 200 years, these tortoises have bred on the volcano, providing a treasure trove of genes from several Galapagos tortoise species, some long extinct on their home islands.
Washington (Wacho) Tapia, director of Galapagos Conservancy’s GTRI, stated, “We didn’t know what we would find when we first went to Wolf Volcano, so the fact that we now have a breeding program in place to restore Floreana tortoises to their home island is a dream come true.”
The restoration of a tortoise population on Floreana Island with high genetic similarity to the island’s original tortoise is part of a larger island restoration program, which includes the elimination of introduced species (rodents and cats), and the return of other species that disappeared from the island (the native snake and the Floreana mockingbird, among other possibilities).
Walter Bustos, director the Galapagos National Park, stated, “Finding these tortoises and starting this long-term breeding program is an important component of the GNPD’s vision for Galapagos — restoring island ecosystems and ensuring long-term ecological and evolutionary processes.”
All photos © GTRI archives except tortoises on Wolf Volcano © Paul M. Gibbons.