A team of Galápagos Conservancy experts and park rangers from the Galápagos National Park Authority, led by Dr. Jorge Carrion of the Galápagos Conservancy, recently embarked on an important mission to protect one of the few remaining wild populations of the yellow land iguana (Conolophus subcristatus) in the Galápagos Islands. The group traveled to a remote, rugged, and rarely visited location on the southeast coast of Isabela Island: Cartago Bay. There they spent eight days traversing hot lava fields and small hills covered with vegetation in search of the elusive iguanas, capturing, measuring and tagging many of them, collecting important biological samples along the way. This population is one of the last in the wild on Isabela Island and has not been monitored for 20 years. What the team learned gives hope for the recovery of this isolated population of endangered lizards.

Population Monitoring

During the expedition, the team captured 288 yellow land iguanas : 117 females and 171 males. These strong, brave animals are difficult to catch, much less keep. Despite this, the team was able to collect measurements of each iguana captured, allowing them to compare population size, distribution patterns, and changes in the iguana's conservation status.

Of the 288 individuals, 50% had never been tagged before. whereas the remaining 50% previously had subcutaneous identification devices. Notably, several of the iguanas recaptured in 2024 were part of a captive breeding program started in the late 1970s. Given that these individuals were reintroduced to Cartago Bay as juveniles decades ago, they are now around 50-60 years old, suggesting that some individuals have not only survived, but are thriving, highlighting the success of this reintroduction program.

Dr. Jorge Carrion noted that monitoring has resulted in an estimate of the current population of 600–700 individuals in Cartago Bay. “We also noted the positive effects of removing feral goats, which allowed iguana habitat to be restored by increasing the amount of food available to iguanas, leading to strong growth and good survival,” he said.

Collection of biological samples

Another important task performed during the expedition was the collection of biological samples. Blood and feces from the iguanas have been collected and will soon be analyzed to provide information about the genetic health of the population, the iguanas' diet and the presence of any diseases. The collection of this information provides data for the development of effective strategies for the protection of this emblematic species, both here in Cartago Bay and elsewhere in the archipelago.

Recording other interesting species

In addition to monitoring the iguanas, the team recorded the presence of other notable species in the area. Invasive species are of particular interest because they pose a significant threat to yellow land iguanas. Although no invasive plant species were recorded during this expedition, many feral cats were observed. Cats eat young iguanas and can potentially disrupt iguana reproduction and therefore remain a major threat to them.

Expedition Success

The Cartago Bay expedition marked an important milestone in the effort on the conservation of yellow land iguanas. The expedition's activities, from population monitoring to collection of biological samples, provide valuable information to develop long-term conservation strategies for the species. The discovery of previously tagged individuals provides a clear indicator of the success of the captive breeding program and ongoing efforts to reintroduce and restore young iguanas into the wild.

A team of scientists, technicians and park rangers have witnessed the ecosystem steadily recovering following the removal of feral goats, which increased food resources for the iguanas. Dr. Carrion summed it up best: “We are seeing the fruits of decades of dedicated work to restore land iguanas in this critical area of ​​the Galapagos Islands.” This achievement is just the beginning. With each expedition, progress is made in protecting iconic species that are not only interesting in their own right, but also vital to maintaining the archipelago's ecosystems. The Galápagos Conservancy reaffirms its commitment to advancing the science and conservation of not only the yellow land iguana, but all the species that make the Galápagos Islands a global treasure.

Source: galapagos.org

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