Espanola Tortoise

Three globally endangered, interacting species are restricted to Española Island in the Galapagos Archipelago: the waved albatross (the world’s only tropical albatross), a morphologically and genetically distinct lineage of giant tortoise, and a large-seeded, arboreal prickly pear cactus. Scientists and managers agree that restoring Española is a major priority for conservation in Galapagos but how best to proceed with conservation management is less clear. Many important questions remain unanswered. The prevailing question is whether active management is required to meet the needs of these species or should nature be left to take its course, albeit unnatural due to human-caused changes in the past?

Project Title: Understanding Interactions among Three Globally Endangered Species — the Waved Albatross, the Española Giant Tortoise, and the Giant Tree Cactus — to Inform Conservation Management of Española Island, Galápagos

Primary research objectives in the research and monitoring program for Española are to:

1. Generate a definitive estimate of current tortoise population size
2. Synthesize three decades of mark-recapture information gathered for tortoises on Espanola Island to estimate variation in tortoise survival rates, body condition, somatic growth rates and population size over time since reintroduction
3. Develop a population projection model for tortoises based on the estimates of survival derived from the tortoise mark-recapture study on Espanola and apply the model to explore likely future scenarios for tortoises on both Espanola and Pinta Island (given that some proposed management actions for restoring tortoise populations to Pinta Island involve Espanola tortoises drawn from captivity or Espanola itself)
4. To elucidate tortoise-cactus-woody plant interactions with a particular focus on whether tortoises influence regeneration of cactus and woody plants as well as the extent to which woody plants influence tortoise and cactus distribution
5. To elucidate albatross-woody plant interactions
6. Project likely future distributions of tortoises and waved albatross under different scenarios of woody plant cover.
7. Assess size and distribution of the “lost” albatross colonies in the interior of Española
8. Perform carbon isotope analysis of soils on Espanola Island to generate insights about vegetation history.

Location: Ecuador

Timeline: 2009-2013

Field participants:
Park Guards of the Galapagos National Park Service

Principal Investigator: James P. Gibbs, SUNY-ESF

Galapagos Conservancy, Galapagos National Park Service

James P. Gibbs, SUNY-ESF, Syracuse, NY 13210 USA,, 315/470-6764