With some assistance from a group of environmentalists, an iguana species that vanished from one of the Galápagos Islands about 200 years ago seems to be making a comeback.
Iguanas' Comeback in an Island in the Galápagos
John Cobb/Unsplash
Charles Darwin was the last person to see a Galápagos land iguana on Ecuador's Santiago Island in 1835, as per NPR.
The iguanas were nonexistent when a Californian expedition party arrived in 1906.
It's also thought that this species of iguana has been extinct in Santiago for the past 187 years, however, it is still present on the other Galápagos Islands.
While exploring the island in late July, a group of researchers and park rangers found new lizards of varied ages, which is evidence that the species has been successfully reintroduced.
And as a result, the ecology is flourishing, claims Jorge Carrión, the Galápagos Conservancy's director of conservation.
He said that the deeds themselves are the proof.
The presence of lizards of various ages and unmarked animals indicates that iguanas are reproducing in their native habitat.
Conservationists carefully considered how a restoration of the species would impact the ecology before deciding to reintroduce the land iguana.
Like the Galápagos giant tortoise, these lizards are considered to be engineering species since they are essential to preserving an ecosystem's healthy balance.
Land iguanas and tortoises, which are the main herbivores on the Galápagos Islands, disperse seeds across the landscape and aid in modeling the plant communities, according to Carrión.
Additionally, the way they walk leaves open areas that other creatures can use.
Invasive species, such as feral pigs, cats, goats, and donkeys, are thought to be to blame for the extinction of the Galápagos land iguanas.
Whalers and other seamen brought these unwanted animals to some of the islands, including Santiago.
They destroyed the ecology by consuming the flora that supported other species, and some even ate the iguanas.
Because of this, before iguanas could be reintroduced to the island, scientists had to remove all non-native creatures from it.
Through the Galápagos Conservancy's Project Isabela, which was finished in 2006, this was accomplished over nine years.
The restoration of land iguanas, according to Carrión and his colleagues, has taught them an essential lesson: if the cause of an ecological disturbance is eliminated (in this case, an invasive species), the ecosystem can recover and resume its natural dynamics.
Beginning in 1997 and ending in 2006, Project Isabela had the objective of eradicating large invasive mammals from northern Isabela Island (about 250,000 hectares), Santiago Island (58,465 ha), and Pinta Island (5940 ha), as per Galápagos Conservancy.
The initiative got its start as a reaction to the extensive ecosystem damage that goats that were imported caused to the Alcedo Volcano in northern Isabela.
The number of goats in northern Isabela was believed to reach 100,000 at the beginning of Project Isabela.
Before the arrival of helicopters, which were necessary for the start of operations on northern Isabela, eradication efforts moved to Santiago, the largest of the islands, which served as a training field.
The goat population surged within 10 to 15 years of their introduction on the southern slopes of Alcedo Volcano, severely degrading the ecology.
The damage was particularly noticeable on Alcedo's southern rim, which serves as a crucial gathering spot for giant tortoises during the cool, dry gara season.
On the rim, the thick trees provide much-needed shade.
Thick gara mists flowed up the volcano's outer slopes, got caught in the numerous epiphytes that inhabited the trees, and eventually dropped to create shaded pools that were essential for tortoises during the dry season.
By the early 1990s, the goats had decimated the forest, removing the gigantic tortoise-essential shade and water source.
Birds, insects, and plant species that are native or endemic were also badly impacted.
To the more northern volcanoes, Darwin and Wolf, the goat population kept growing.
Island ecosystems are particularly vulnerable to the destruction of feral goats, which largely degrade ecosystems through overgrazing, destroying forests, and creating erosion.
Goats were initially brought to the Galapagos Islands in the 1800s and subsequently released on 13 islands.
They were exterminated on five of the smaller islands by 1997.
Goats were still present at the commencement of Project Isabela on Pinta, Santiago, the five inhabited islands, and a small islet off the west coast of Isabela.
Goats had completely disappeared by 2006 from Pinta, Santiago, and northern Isabela; just a small number survived in southern Isabela.
On the volcanoes of Santiago and Alcedo, donkeys were eradicated (the only places on the three islands they occurred).
Pigs had also left Santiago.
The greenery recovered miraculously as the goat populations decreased.
From the goats' stumps, little trees started to grow.
The number of endemic species grew, including Opuntia cactus, forest tree seedlings, and species of highland shrub.
Numerous species that were previously confined to protected craters and fenced enclosures where they were protected from goats were discovered by scientists.
