The ultimate goal of Project Isabela, initiated in 1997 and completed in 2006, was the eventual restoration of Pinta (5940 ha) and Santiago (58,465 ha) Islands and the larger, northern portion of Isabela Island (approximately 250,000 ha; the whole island encompasses 458,812 ha). The project began in response to the massive destruction by introduced goats of both native vegetation and terrain. The goat population on northern Isabela was estimated at 100,000 animals.
Santiago Highlands before goat removal. (© Marc Patry)
Santiago Highlands after goat removal. (© GNPD)
In 1997 the Charles Darwin Foundation (CDF) and the Galapagos National Park Service (GNPS) held an international workshop of experts to determine the feasibility of success of such a major undertaking and to design an all-encompassing action plan. As of 1997, the largest island with a successful goat eradication was Auckland Island in New Zealand (49,975 ha); however, the 105 goats removed occupied a mere 4000 ha. The next two largest islands with successful goat eradications were Lanai in Hawaii (35,000 ha, unknown size of goat population) and San Clemente Island in California (14,800 ha with approximately 29,000 goats). The concept and plan developed at the workshop would become the largest, most ambitious ecosystem restoration project in a protected area worldwide. The ultimate measure of success would be the complete removal of all feral goats from Pinta, Santiago, and northern Isabela, followed by the reestablishment of natural ecological conditions and evolutionary processes.
Among the suite of introduced animals, feral goats are particularly devastating to island ecosystems. Primarily through overgrazing, they cause both direct and indirect impacts resulting in ecosystem degradation and loss of biodiversity. First introduced in Galapagos in the 1800s and early 1900s, goats were eventually found on 13 islands. By 1997, they had been eradicated on 5 of the smaller islands. At the start of Project Isabela, goats were still found on Pinta, Santiago, the 5 islands with human habitation, and a small islet off the west coast of Isabela.
The giant tortoises on Alcedo Volcano provided the catalyst for Project Isabela. In the 1970s the feral goats present on southern Isabela finally crossed the hostile terrain of the Perry Isthmus and arrived at the lower southern slopes of Alcedo Volcano. It would take another 10 to 15 years for the goat population to explode causing massive ecosystem degradation. The destruction was most evident on the southern rim of Alcedo, a gathering place for giant tortoises during the cool, dry, garúa season. The dense forests on the rim created shade and the critical drip pools where tortoises congregated. The thick garúa mists drifting up the outer slopes of the volcano became trapped in the many epiphytes living in the forest and then dripped to the pools below. But the goats arrived like bulldozers, destroying the forest and thus the tortoise shade and water supply. Other native and endemic species, including birds, insects, and plants, were also negatively impacted by the destructive goats, whose population continued to expand to the more northern volcanoes, Darwin and Wolf. Their arrival at each new portion of Isabela resulted in pristine forests and shrubby vegetation being transformed into barren grasslands and in massive erosion of the steep volcanic slopes.
To achieve a successful eradication on the scale of Isabela and Santiago and in such a remote location required a tremendous amount of logistical support, financial resources, organizational ability, and most importantly of all – new and better eradication technologies and an expert field team. Project Isabela was designed with three phases:
Beginning in 1997, professional training of a team of highly skilled park wardens from Galapagos began. By the end of the project, this team would become one of the best hunting and eradication teams worldwide.
The modern, high-tech hunting methods were first put into practice to eradicate the remaining pig population on Santiago and the few remaining goats on the small island of Pinta. Field trials on smaller islands helped to hone the team for the large-scale work on Isabela and resulted in the achievement of additional Galapagos conservation goals. Cutting-edge technology, including the use of helicopters for aerial hunting and GIS tracking, ensured swift and efficient removal of the feral goats. Data management became as critical for the hunters as marksmanship skills. Being naturally gregarious, sterilized Judas goats, fitted with radio collars and then released into the population, would seek out the remaining feral goats, allowing them to be located through radio telemetry and then removed.
With the removal of the last pig from Santiago in 2000, work there shifted to the huge goat population, giving the Project Isabela team a chance to try the new methodologies and hone their skills on an island much larger than Pinta. Goat hunting finally began on northern Isabela in 2004. By the end of 2005, goats were gone from Pinta, Santiago, northern Isabela, and only a few remained on southern Isabela. Donkeys had been eliminated on both Santiago and Alcedo Volcano (the only places on the three islands that they occurred). And pigs were gone from Santiago.
As the goat populations declined, the vegetation underwent an amazing recovery. Small trees began regenerating from the stumps left by the goats. Highland shrub species, forest tree seedlings, Opuntia cactus, and other endemic species increased. Scientists found several species that had previously been restricted to protected craters and fenced enclosures where they were protected from goats. Galapagos rails were once again abundant in the highlands.
In conjunction with the eradication campaign, the GNPS and the CDF carried out extensive fieldwork and creative management to catalog, conserve, and permit the natural recovery of the once splendid vegetation and ecosystems of these islands. Current research is focused on ensuring that ecosystem restoration proceeds towards a more pristine condition – this requires ensuring that any introduced plant species do not out-compete the native vegetation, that natural openings occur in the native forests, and that the final result is a Galapagos similar to that witnessed by Charles Darwin in 1835.
While the most talked about and most easily visible components of Project Isabela are the eradications of feral goats, pigs, and donkeys, the project had other important elements:
- Improvement of the inspection and quarantine system to prevent future introductions.
- Development and implementation of cost-effective methods of eradicating, controlling, and mitigating the impact of invasive species, which can be used on other islands and for other species.
- Building capacity for both eradication programs and for applied research to better understand the nature of current and future threats of invasive species, and to plan mitigation efforts. Much has been done to develop models for predicting and prioritizing potential threats and the effectiveness of different eradication and control measures.
- Assuring that future human activity on Isabela is consistent with the long-term management of invasive species.
- Establishment of funding mechanisms to ensure ongoing monitoring and management activities, as well as new eradication efforts elsewhere in the Galapagos.
- Building awareness in the archipelago and the mainland regarding the challenge and importance of ecological restoration efforts and the long-term management of invasive species.
The Project Isabela story illustrates the benefits of close collaboration between scientists and resource managers. When based on robust scientific research and management, such as that undertaken by the CDF and the GNPS, innovative partnerships like Project Isabela represent a model for integrated conservation efforts worldwide.
Impacts of Project Isabela on Galapagos Conservation
With field operations ended in March of 2006, the Project Isabela team at the National Park focused on the remaining islands with goats – southern Isabela (only 20-30 goats remained), Floreana, San Cristóbal, and Santa Cruz. Major efforts to eradicate goats from some of these islands had already occurred and we can finally foresee a future with a once-again goat-free Galapagos.
Lessons learned during Project Isabela have also been applied to a critically endangered endemic species – the Floreana mockingbird – and to another group of aggressive, introduced mammals – rodents. In March-April 2007, the CDF and the GNPS held two international workshops in Galapagos to bring together experts in the fields of recovery of bird populations and eradication of introduced rodents. The result of both workshops was a fully developed action plan, similar to the original plan for Project Isabela. The impact of Project Isabela on the future of Galapagos will be felt not only where goats, pigs, and donkeys were removed, but also in all the projects that grow out of the knowledge and skill acquired during this ambitious and successful project.
Project Isabela received support from: Galapagos Conservancy, The Darnton Trust, Ezekiel R. and Katherine W. Dumke, Frankfurt Zoological Society, Friends of Galapagos Netherlands, Friends of Galapagos Switzerland, Galapagos Conservation Fund, Global Environment Facility, The Lutz Foundation, The Mars Foundation, Stephen L. Merrill, The Prospect Hill Foundation, The Stewart Foundation, USAID, Van Thienhoven, World Wildlife Fund, and Zanders Sporting Goods.
Brief Timeline for Project Isabela
1995: Tortoise Summit held in the UK. The tortoise problems on Alcedo Volcano and potentially all of northern Isabela stimulated concerned members of the Charles Darwin Foundation to hold a summit in 1995 to initiate a discussion focused on the problem of goats on Isabela. The main conclusion was that an aggressive, ecosystem-wide approach was necessary and that such an effort would require new eradication technologies. In October 1995, the “Campaign to Save Alcedo” was launched to initiate building the foundation for an eventual island-wide ecosystem restoration project.
1997: International workshop held in Galapagos; produced the Project Isabela Plan. The project was developed as a bi-institutional project of the CDF and the GNPS. The existing park warden team working on pig eradication on Santiago became the first members of the Project Isabela team and the completion of the pig eradication was incorporated into the project.
1999: Initiation of the Pinta phase of the Project. Goat eradication of Pinta was used to test new methodologies and to train the team for the large-scale work on Isabela.
2000: The last pig was removed from Santiago; more than 18,000 pigs were removed during the entire Santiago program begun more than a decade before.
The Global Environment Facility (GEF), a strategic partnership of the United Nations Development Program (UNDP), the United Nations Environment Program (UNEP), and the World Bank, approved a six-year, $13.3 million initiative to fund invasive species work in Galapagos, with Project Isabela as the primary focus.
2001: Transitioned from pig eradication to goat eradication on Santiago. Santiago was used as second, larger trial area for northern Isabela and eradication work was initiated while waiting for the helicopters that were needed to begin the work on Isabela.
2003: Pinta declared goat-free.
2004: Last donkey removed from Santiago.
Aerial hunting for goats began on Santiago. Judas goats were released on parts of Santiago by the end of the year. More than 200 Judas goats were used on Santiago.
Santiago was declared pig-free by the end of the year.
Ground hunting on Isabela began followed soon after by aerial hunting. During the first seven months, more than 55,000 goats were removed and donkeys were eradicated. Judas goats were released by the end of 2004. In all, some 770 Judas goats were used on Isabela, the majority in the north but some in southern Isabela.
2005: Last feral goat removed from Santiago.
Last feral goat removed from northern Isabela; approximately 20-30 goats remained in southern Isabela.
2006: Santiago declared free of all large introduced mammals – goats, pigs, and donkeys. Approximately 20 sterile Judas goats remain for monitoring purposes.
Field operations ended in March 2006. 266 Judas goats remained on Isabela for monitoring purposes.