On Baltra Island, some plants have struggled to regenerate at their usual rate, despite the removal of invasive goats.
Harsher Conditions and Phenological Studies
“This would mean that today we are probably living even harsher conditions than a few decades ago,” says Nicolás Velasco, a researcher at the Charles Darwin Foundation (FCD).
Velasco has spent two years in the Galapagos, observing significant changes in the climate. He is involved in a study on plant phenology, which analyzes how the climate affects the natural cycles of plants, such as flowering and fruiting. “It is very evident that the phenology of endemic plants is changing,” he asserts.
El Niño’s Impact
Another phenological study focuses on the impact of El Niño. This meteorological phenomenon can cause heavy rains that weaken the roots of mature Opuntia echios plants, leading to their downfall.
On South Plaza Island, an original population of 2,000 plants in the 1960s decreased to around 400 individuals in 2014. Some scientists believe that climate change is reinforcing the effects of El Niño.
The Delicate Dance between Cacti and Iguanas
Walking along the marked trails of South Plaza Island, it is common to see yellow land iguanas basking in the sun. Their population is in tune with the ecosystem’s reverberations.
The disappearance of the Galapagos hawk, a key natural predator, has contributed to increasing their number, but with the decline of Opuntia, competition for food has become fierce. As part of the ‘Galápagos Verde 2050’ ecological restoration program, researchers have planted cacti in areas where their numbers have plummeted.
Pressure on Cacti
“You have to be very quick with the fencing because in a couple of minutes the iguanas arrive and start eating them,” says Nicolás. “You can see they are very, very hungry.” Iguanas, originally herbivores, become opportunistic in times of scarcity, even feeding on carrion and swallow chicks.
Interdependence between Species
“Originally there was a good interconnection between the two species [land iguanas and cacti],” comments Nicolás. “Iguanas usually eat cactus fruit, thus spreading the seeds.” In times of turbulent weather, plants suffer more attacks. On Española Island, for example, “super-dry” conditions have led iguanas to eat prickly pear cacti to obtain water before the plant has time to produce seeds.
Underwater, land iguanas also face variable situations. Marine iguanas suffer during El Niño, as the increase in sea temperature depletes seagrass and other food sources.