Satellite imagery aids Galapagos Tortoise conservation

02 July 2011 | News story

How GeoEye imagery is being  used to study Galapagos tortoises on Santa Cruz Island, Ecuador. An example of conservation from space!

From Bailey Gilchrist and IUCN CEC member Mark Brender of GeoEye

Giant tortoises are the native mascot of the Galapagos Islands. Tourists and scientists alike track their annual, extensive migration. However their abundance, distribution, migration routes, habitat choice, diet and ecosystem impacts remain poorly understood which hampers effective conservation. Nesting areas, critical food resources and transition areas are poorly known and inadequately protected from poachers, introduced animals and agricultural developments.

The Max Planck Institute for Ornithology sought to conduct the first-ever, comprehensive ecological study of the Galapagos tortoise habitat, analyzing the animals abundance and distribution on Santa Cruz Island, Ecuador. The study by researcher Stephen Blake utilized satellite imagery of Santa Cruz Island donated to the Institute by the GeoEye Foundation, a non-profit organization dedicated to helping researchers map, monitor, and measure the Earth.

The imagery helped to establish a baseline habitat and land-use maps of the island, allowing researchers to assess land changes and tortoise impact. The study will serve as the first island-wide survey of tortoise abundance and distribution, and use GPS telemetry for the first study of tortoise migration. Additionally, the Institute looks to quantify diet and food availability, seed dispersal potential, and the impact of tortoises on density, recruitment, and survival of keystone plant species.

The primary reason movement ecology of giant tortoises has not been examined for either has been lack of remotely sensed data of sufficient resolution to provide an ecological context for habitat choice by tortoises at the landscape scale in which they operate. Remotely sensed imagery is used to generate a land-use classification and vegetation map of Santa Cruz, a DEM, and a survey of cactus (an endangered yet keystone food resource for tortoises). The imagery will also be used on a web-based moving map that inspires understanding and concern for Galapagos and its ecological heritage.

The data will be applied to several purposes: first the researchers will digitize major landuse types (agriculture, urban, roads and trails) and vegetation features (bare rock, grassland, forest, agricultural complexes, inundated areas, crater vegetation, etc.) to produce baseline habitat and landuse maps. Additionally, the Institute will complete a stratified survey of cactus on the island, and a complete count and map at selected high intensity tortoise use areas. These maps will serve as a monitoring baseline from which change, including change due to tortoise impacts, will be evaluated. A TEM displaying tortoise movements will serve as a scientific resource and an outreach/education tool.

This study will ultimately help the Ecuadorian government plan socioeconomic development options for Galapagos that are compatible with tortoise conservation. It will also provide immediate benefits including jobs, training, and education. Tortoises and functional ecosystems are critical to the tourism-based economy of the Galapagos Islands, yet both are in jeopardy. The Max Planck Institute for Ornithology’s applied research will generate management protocols to help ensure the ecological integrity of Galapagos for the long term.

For more information, contact Bailey Gilchrist bgilchrist@gibraltar-llc.com