Marchena has suffered, like many of the Galapagos Islands, from non-native, invasive species that were introduced by past visitors. The worst culprits were goats. These were brought to Marchena in 1967 before many turned feral and bred in the wild. These in turn wreaked havoc, destroying the declicate natural habitat.
In 1970, a goat eradication program was initiated. By 1979, the island was considered goat free. Not long after, Project Isabela, was launched, becoming the largest, most ambitious ecosystem restoration project in a protected area worldwide. More attention was paid to islands like Marchena and on a scientific visit, goats were discovered once again. Thankfully, the park rangers leapt into action and the goats were quickly dispatched.
In 1988, another threat rose its head: the Little Fire Ant (also know as the 'Electric Ant'). An eradication program was launched and did make a dent, but more recently, a larger area of infestation was discovered.
Little Fire Ants are a very aggressive species that prey on native insects and outcompete other ants. They also feed on nectar and other residues that native wildlife depend on for sustainance. The ant has significantly contributed to the decline in tortoise populations, as they eat the tortoise hatchlings and attack the eyes of adult tortoises. Furthermore, large population declines of scorpions, spiders, and native ants can be directly attributed to these ants.
A key concern for Marchena is the possibility that humans might bring other aggressive exotic species onto the island.
