December 4, 2015
Scientists and Galapagos National Park Directorate (GNPD) rangers recently returned from a major expedition to Wolf Volcano at the northern end of Isabela Island to search for and recover “hybrid” tortoises known to have partial ancestry (and thus DNA) from the extinct Pinta (Chelonoidis abingdonii) and Floreana (Chelonoidis elephantopus ) tortoise species. A total of 32 tortoises were transferred from Wolf Volcano to the Fausto Llerena Breeding Center on Santa Cruz. This is the start of a long-term program to repopulate both islands with tortoises similar to the original species.
During a period of ten days, the group of 27 park rangers and 16 scientists were able to successfully locate and remove 32 giant tortoises, some known to have either Pinta or Floreana tortoise genes and others with very similar shell shape. Blood samples were collected from all and will be analyzed over the next several months. Once the ancestry of all animals is identified, they will be included in a long-term captive breeding and rearing program, with their offspring forming the foundation of tortoise populations on Pinta and Floreana.
This project is part of the Giant Tortoise Restoration Initiative, a collaborative program of the Galapagos National Park Directorate and Galapagos Conservancy begun in 2014, as well as key collaborators including the genetics team from Yale University that has been studying tortoise genetics in Galapagos for over twenty years.
The Park’s ship, the Sierra Negra, left Puerto Ayora on November 18, 2015 loaded with park rangers, scientists, gear, and food and water for 10 days. The following morning, they spread across the western flank of the volcano and established ten separate camps within a 45-square-mile area, from elevations of 500 to 3,600 feet above sea level. The expedition tested the physical ability of the field team as they made exploratory journeys of up to 10 hours a day in their search for tortoises. The terrain of the search areas consisted of large areas of fragmented, sharp lava flows and areas with dense vegetation dominated by thorny bushes, cactus and other native and endemic plants.
Washington Tapia, Director of the Giant Tortoise Restoration Initiative for Galapagos Conservancy and scientific advisor to the GNPD, led the expedition. Each team was provided with a list of priority tortoises with high levels of Pinta and Floreana tortoise genes; these tortoises had been sampled in the 2008 expedition and their blood analyzed by the Yale team. Given the difficult terrain, dense vegetation, weather conditions, and the significant number of tortoises found on the volcano, not all the priority individuals could be located. However, additional saddleback tortoises (a shell shape indicative of Pinta or Floreana genes) were collected; these tortoises had not been sampled in previous expeditions.
Scientists took blood samples from those tortoises for genetic analysis to be carried out at Yale University over the next several months. The team is optimistic about the possible outcomes due to the discovery of males with a shell shape very similar to Lonesome George, the last known Pinta tortoise and a conservation icon.
In addition to finding hybrid tortoises with genes from the Pinta and Floreana tortoise species, the field team conducted monitoring activities related to the size and overall status of the tortoise population on Wolf Volcano. A total of 1,323 tortoises of various ages, most pertaining to the Wolf species (Chelonoidis becki), were marked. Tapia believes that the blood samples taken from all saddleback tortoises encountered will provide more accurate data on the number of hybrid Pinta and Floreana tortoises on the Island for future expeditions.
Upon arrival at the Tortoise Center on Santa Cruz, male tortoises were separated from females to prevent breeding activity until the genetics of all tortoises are determined. The tortoises are currently undergoing a temporary quarantine process to ensure that they did not transfer seeds from Isabela to Santa Cruz; this involves daily review, removal and disposal of all scat until no seeds remain.
Genetic analyses, to be carried out at Yale University, will determine which individuals should be bred to ensure the highest diversity and level of original genes from the Pinta and Floreana tortoises. This is yet another example of the important role that tortoise genetics is playing in long-term management decisions for the recovery of all Galapagos tortoise populations.
This project is one of the most ambitious species recovery efforts ever attempted, and will ultimately restore two extinct species and as well as the ecological integrity of Pinta and Floreana Islands.
Content based on a press release from the Galapagos National Park Directorate, translated with their permission.