The Giant Tortoise Restoration Initiative (GTRI) is a significant, multi-institutional and multi-year project. Along with our main partner, the Galapagos National Park Directorate, we would like to thank all of the Galapagos Conservancy members who support our efforts as well as the Phillips Family Foundation, Mohamed bin Zayed Species Conservation Fund, Fondation Ensemble, Lawrence Foundation, and all those who provide support for the international scientists who are an integral part of the GTRI.
The giant tortoise was one of the most devastated of all species in the Galapagos Islands. Only the rice rat was hit harder, with the majority of endemic rat species now extinct. Humans first exploited giant tortoises as a food source; a practice that continues today at a low rate. In later years, they were harvested for oil. Some introduced species (primarily rats, pigs, dogs, and the Solenopsis ant) prey on tortoises (particularly eggs and young tortoises); others (goats and donkeys) damage or destroy tortoise habitat.
With the establishment of the Galapagos National Park and the Charles Darwin Foundation (CDF) in 1959, the CDF launched a systematic review of the status of the tortoise populations. Only 11 of the 14 original populations remained, and most of these were endangered if not already on the brink of extinction. The rearing program for giant tortoises began in 1965 with the first transfer of tortoise eggs from Pinzón Island to the new tortoise center on Santa Cruz. This was in response to the status of the Pinzón tortoise population, which consisted of fewer than 200 old adults. All of the hatchlings had apparently been killed by introduced rats for perhaps more than a century. Without help, this population would eventually disappear. The only thing saving it was the longevity of the tortoise. In 1970, the first 20 tortoises were repatriated to Pinzón when they had reached an age and a size (about 4-5 years) at which they were considered “rat proof.”
The situation on Española Island was even worse — only 14 tortoises remained (2 males and 12 females). These were all brought into captivity and a tortoise breeding program began. A third Española male was returned to Galapagos in 1976 from the San Diego Zoo. An improvement in nesting areas and incubation and rearing techniques over the years has made this one of the most successful programs of the CDF and its long-term partner, the Galapagos National Park Directorate (GNPD — established in 1968). Since the 1960s, these organizations along with a team of international scientists have made tremendous strides to address the critical state of giant tortoise populations across all of Galapagos.
The GNPD took over management of the tortoise center in the late 1990s. In the 2000s, CDF ended its herpetology program to focus on other high priority issues facing Galapagos biodiversity. Galapagos Conservancy later joined with the GNPD to ensure that the next 50 years of tortoise conservation will be as successful as the first 50 years. Successes of the tortoise breeding and eradication programs include the repatriation of more than 800 tortoises to Pinzón and nearly 2,000 tortoises to Española; the removal of feral goats — a major threat to tortoise populations — from Pinta Island (5,940 ha), Santiago Island (58,465 ha), and the northern portion of Isabela Island (approximately 250,000 ha); and the release of 39 sterilized tortoises on Pinta Island to serve as “environmental engineers” nearly 40 years after Lonesome George was taken from Pinta to the Santa Cruz Tortoise Center.
Long-term Program Goals:
Restoring tortoise populations to historical numbers, including those considered “extinct in the wild,” through a combination of in situ management, breeding and rearing tortoises where appropriate, and repopulation of Santa Fe Island, where the endemic tortoise species is extinct, through the use of an analog (closely-related) species.
Evaluate habitat conditions and restore where necessary.
Survey the lesser known tortoise populations to inform future management.
Continue using advances in genetics to refine tortoise conservation.
Continue to improve and expand the GNPD’s tortoise centers to ensure healthy animals and constant support of conservation activities.
Advances Since the GTRI’s Launch:
Release of 206 juvenile Española tortoises (the species genetically closest to the Santa Fe tortoise) onto Santa Fe in 2015, and another 190 tortoises in 2017, to initiate the repopulation of that island.
Identification of a new species of tortoise — the Eastern Santa Cruz Tortoise — bringing the total of known Galapagos tortoise species to 15.
Ongoing monitoring of the giant tortoise-cactus-woody vegetation complex on Española Island to inform future habitat restoration work.
Collection of 32 tortoises from Wolf Volcano, along with blood samples from an additional 148 tortoises; genetic analyses are underway to determine the best breeding pairs or groups to initiate breeding programs for both Pinta and Floreana Islands.
First-ever comprehensive census of the tortoise population (Chelonoidis chathamensis) on San Cristóbal Island.
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