By Wacho Tapia, Galapagos-based director of the Giant Tortoise Restoration Initiative (GTRI)
Several weeks ago, I returned from my second trip to Santa Fe Island this year. Santa Fe is a small island in the center of Galapagos where giant tortoises went extinct about 150 years ago. In our support of the Galapagos National Park Directorate's goal to restore the ecosystem of Santa Fe, we are planning the return of giant tortoises to the island as part of the Giant Tortoise Restoration Initiative (GTRI).
On the first trip in May of 2014, I was accompanied by Dr. James Gibbs and park ranger Jeffreys Málaga. In preparation for this exciting scientific and ecological event, James, Jeffreys and I evaluated the current conditions on Santa Fe and selected 20 permanent quadrants for long-term monitoring of the vegetation and general ecology of the island. It rained most days while we were there, resulting in a burst of herbaceous plants. The normally reddish-brown soil turned into a green carpet. Although we had to work under very wet conditions, it was a magnificent experience to see the lush countryside and be constantly accompanied by the Santa Fe land iguanas (Conolophus pallidus).
Rainy conditions turned the reddish-brown soil of Santa Fe a lush green earlier this year:
When I returned to Santa Fe in June — this time with just a construction crew — the rains had ended and the conditions had changed. The greatest impression was the complete disappearance of the green carpet and the return of the red soil, making it look like an entirely different island.
The single goal of the June trip was to fence in 10 of the 20 quadrants established in May. By creating plots where land iguanas and giant tortoises cannot enter, we would then be able to compare the vegetation in the 10 open plots (with grazing) with the 10 fenced plots (no grazing) to determine the impact of the native herbivores on the ecosystem.
Some of the newly-fenced plots on Santa Fe Island:
In addition to the 20 quadrants established in May, I added a one-hectare quadrant in which I marked all cactus plants in order to be able to measure the impact of a potential El Niño event on the population. Cactus is by far the most important species for tortoises, carrying them through periods of prolonged drought by providing both food and water.
With the quadrants established and the fences built, we can now plan the release of some 200 young tortoises from Española, the species most closely related to the Santa Fe tortoise, which will be used as replacements for the original tortoises — or as we say, “an analog species.” The release will take place once the rains return and the island greens up again, which will help to ensure their initial survival. We will then mark some of the tortoises with radio telemetry tags so that we can follow them as they begin to explore the island.
Stay tuned to this space for the latest developments on the GTRI — and there will be many more to come.
Wacho Tapia is the Galapagos-based Director of the GTRI. A Galapagos native and reptile expert with decades of field experience, Wacho previously led the science program and technical group at the Galapagos National Park Directorate for 15 years.