On the island of Santa Cruz they are looking for ways to control its invasive expansion, while on the mainland of Ecuador it is in a vulnerable situation.
Galapagos Island (EFE) · The cedrela tree is a threat to the migration processes of the Galapagos giant tortoises, where on the island of Santa Cruz they are looking for ways to control its invasive expansion, while in the continental territory of Ecuador it is in a vulnerable situation.
Introduced in the 1940s to the Galapagos, at mature age the ‘cedrela adorata’, known as cedrela, can measure up to 30 meters, which provides shade around it, causing other species to leave, the director of the Park told EFE. Galapagos National, Arturo Izurieta.
“There are large patches (of cedrelas) that coincide with certain turtle migration routes,” Izurieta noted.
The aforementioned species of cedrela – he said – is listed as “vulnerable” on the Red List of the International Union for Conservation of Nature, “while here it is a pest.”
Passage blocking
In Santa Cruz, which is located in the center of the archipelago, there are two species of endemic giant tortoises in critical danger: the chelonoidis porteri and chelonoidis donfaustoi.
Patrick Moldowan, principal investigator of the land turtle project at the Charles Darwin Foundation (FCD), told EFE that the cedrela spreads “very quickly, particularly in the upper part of the island, which is more humid, but it is also present on other islands.
The tree is mainly in agricultural areas and little by little it is “entering the Park areas (Galapagos National) and displacing native and endemic plant species,” he stated.
“The turtles do not go through cedrela forests because it is cooler, it is very dense and, in general, the cedrela forest also brings other species of invasive plants,” he noted.
Thus, in their migration, the turtles do not go beyond the cedrela forests or take much longer routes to “try to find a gap where there is no cedrela so they can follow their route,” he said.
An immediate concern for scientists is that the turtles will lack the energy to complete their journeys and will not be able to feed, and, in the long term, they fear “the impact on their survival potential.”
Migrating is important due to the type of diet, since in the high and low parts there is different vegetation and nutrients.
FACT Introduced in the 1940s in the Galapagos, at mature age the ‘cedrela adorata’, known as cedrela, can measure up to 30 meters. Conservation dilemma
Cutting down the tree could have greater impacts, because when it falls “it takes everything away” and pruning it is expensive, Izurieta reflected, noting that cedrela wood is highly desired by carpenters, so the situation becomes an economic challenge. ecological and social.
For the executive director of the CDF, Rakan Zahawi, Galapagos faces a “conservation dilemma since, on the one hand, the cedrela thrives here and is useful for the local economy, and, on the other hand, it represents a real threat to the turtles.” giants and other local biota.
“Here in Santa Cruz,” said Moldowan, “the objective should really be the control and management of the cedrela and not necessarily its eradication,” since what is intended is to allow the turtles to migrate along routes that they have used “for thousands of years.” ».
A first step would be to map the cedrela to know its invasion pattern, with a view to future management, and bring together the National Park, conservation organizations and the population to define management strategies.
Chain of life
Moldowan warned about the great impact of the cedrela on other vegetation since they have observed that “the native biodiversity of the island drops by 40% in the presence of the cedrela, but, in contrast, the presence of other species of invasive plants increases by 30% ».
Many Galapagos species have evolved very closely to each other, and if that chain is broken or damaged, “it can have consequences far beyond this species,” he warned.
He recalled that, through their digestive system, turtles disperse seeds of endemic and invasive plants, and being known as engineers of their ecosystem, they are very important for recycling soil nutrients.
“By affecting their trajectory, it could affect those services they have towards the ecosystems, which are fundamental for the biodiversity of the islands, and of Santa Cruz in this case,” he concluded.