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Ecosystem Restoration: Giant Tortoise Restoration Initiative
CURRENT

PROJECT:

Giant Tortoise Restoration Initiative

PARTNERS:   

Galapagos National Park Service, Charles Darwin Foundation, and international scientists.

STATUS:

International planning workshop took place in
July 2012; funding needs for follow-up research and management are currently being identified.

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.

Tortoise by Jonathan Paul

Tortoises play the important role of "Ecosystem Engineer" across the Galapagos Islands. (Greg Shenkler)

 

With the establishment of the Galapagos National Park Service (GNPS) and the Charles Darwin Foundation (CDF) in 1959, a systematic review of the status of the tortoise populations began. 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 response to the conditions of the tortoise population on Pinzón Island, where fewer than 200 old adults were found. 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. The rearing program began in 1965, with the first transfer of tortoise eggs from Pinzón to the new tortoise center on Santa Cruz. 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 the breeding program was initiated.  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 GNPS and the CDF.  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.

Successes of the tortoise breeding and eradication programs include the repatriation of more than 550 tortoises to Pinzón and more than 1,700 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 to serve as “environmental engineers” 38 years after Lonesome George was removed from the island.

Recent advances in the eradication of introduced mammals and our understanding of tortoise ecology and genetics have created opportunities that would have been impossible to imagine even a few decades ago. Galapagos Conservancy, the GNPS, the CDF and international scientists are working together to expand the Giant Tortoise Restoration Initiative to build on these evolving opportunities.

Over a 10-year period the project will:

  • Restore tortoise populations, including those considered “extinct in the wild,” through a combination of in situ management, breeding and rearing tortoises where appropriate, and repopulation of an island where tortoises are extinct through the use of an analog (closely-related) species
  • Evaluate habitat conditions and restore where necessary
  • Improve education/outreach in service of giant tortoise conservation