Galapagos Giants Reclaim Island After 150 Years

Giant tortoises have made a triumphant return to Floreana Island in the Galapagos, marking their first presence in nearly 150 years after their local extinction. A significant cohort of 158 juvenile giant tortoises, ranging in age from eight to thirteen years old, has been released as part of an ambitious initiative aimed at revitalising the island’s depleted ecosystem. Floreana, situated in the southern reaches of the Galapagos archipelago, was once a thriving sanctuary for tens of thousands of these majestic creatures. However, their numbers plummeted and eventually vanished in the 19th century. This decline was largely attributed to the arrival of sailors, whalers, and settlers who introduced invasive mammal species. These introduced animals wreaked havoc on the island’s delicate environment, decimating native flora and fauna. By the time Charles Darwin set foot on Floreana in 1835, the island’s tortoise population was already on the brink of collapse.

The tortoises reintroduced to Floreana are not direct descendants of the original population but rather hybrids. These individuals have been selectively bred for reintroduction, utilising a remnant population of tortoises with Floreana ancestry found on Wolf Volcano, located in the northern part of Isabela Island, the largest island in the Galapagos.

These hybrids possess between 40 and 80 per cent of the genetic makeup of Chelonoidis niger, a species that has been extinct on Floreana for approximately 150 years. Christian Sevilla, the director of ecosystems for the Galapagos National Park, explained that the project involved carefully selecting adult tortoises with the most robust genetic profiles. The goal was to gradually restore the purity of the extinct Floreana species. The release of these juvenile tortoises, strategically timed with the onset of the island’s first winter rains, represents the initial phase of a larger plan. A total of 700 tortoises are slated for gradual introduction to Floreana. Fredy Villalba, the director of the Galapagos National Park’s breeding centre on Santa Cruz Island, highlighted the suitability of the released specimens. “They are large enough to be released and can defend themselves against introduced animals such as rats and cats,” he stated. This statement is bolstered by the fact that an invasive species eradication program, initiated in 2023, has already seen the successful removal of many rats and feral cats from the island.

The Ecological Role of Giant Tortoises

The return of giant tortoises is more than just a symbolic victory; it’s a crucial step towards ecological restoration. These herbivores play a vital role in shaping and maintaining island ecosystems.

• Habitat Regeneration: Through their grazing habits, giant tortoises stimulate the regeneration of native plant species. This process helps to maintain and restore the diverse habitats that are essential for the survival of various other species.
• Seed Dispersal: As they traverse the island, giant tortoises act as natural seed dispersers. They consume fruits and vegetation, and their droppings spread seeds across different areas, aiding in the propagation of native plants and increasing biodiversity.
• Supporting Biodiversity: The habitats maintained by tortoises provide crucial shelter and resources for a wide array of wildlife, including other reptiles, invertebrates, and native bird populations.

The reintroduced tortoises will now share their revitalised home with Floreana’s human population of nearly 200 residents. They will also coexist with a rich tapestry of wildlife, including flamingos, marine and land iguanas, penguins, seagulls, and hawks. Veronica Mora, a resident of Floreana, expressed the local community’s long-held aspirations. She told the Associated Press that the release of the tortoises, who have already begun to explore their new surroundings, had been a dream come true. “We are seeing the reality of a project that began several years ago,” she remarked, underscoring the culmination of years of planning and effort.

A Natural World Heritage

The Galapagos Islands have long been recognised for their unparalleled biodiversity. In 1978, the United Nations designated the archipelago as a Natural World Heritage Site. This prestigious recognition was a testament to the extraordinary concentration of unique terrestrial and marine species found within the islands, a testament to their remarkable ecological significance. The reintroduction of the giant tortoises to Floreana is a significant step in preserving this legacy for future generations.