Marquez, Cruz

English

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THE GIANT TORTOISES AND THE GREAT FIRE ON ISABELA 
by 
Cruz Marquez 
Charles Darwin Research Station 
The forest fire on southern Isabela Island in 1985 began when farmers were burning off the brush. Owing 
to the prolonged drought the vegetation was like tinder and the wind quickly carried the flames beyond the 
farms and into the National Park. The worst consequences were prevented by the combined efforts oflocal 
volunteers, the Ecuadorian armed and civil defence forces, water-carrying planes from Canada, the U.S. 
Forestry Service and the Charles Darwin Research Station. After heroic exertions in almost unbearable 
heat the fires were gradually brought under control but it was only after 75 days that nature, in the form of 
heavy rain, finally ended the conflagration which had by then covered some 20,000 hectares (50,000 acres). 
There are two distinct races oftortoises on southern Isabela, each confined to its own volcano, Geochelone 
elephantopus guntheri on Sierra Negra and G.e. vicina on Cerro Azul. The populations of both have been 
sadly diminished by man, dogs and pigs and, until the Darwin Foundation was organized, their survival 
was in serious doubt. To compensate for inadequate breeding in the wild, their numbers are now 
supplemented by captive breeding at the Darwin Station. The fire was centred between the two volcanoes 
so neither subspecies was safe. 
As the huge fire reached closer and closer to the areas where the tortoises were located, the National Park 
Service decided to evacuate a selection of both races, including males, females, sub-adults and juveniles, to 
places of refuge on the coast where the terrain was almost devoid of combustible vegetation, but within 
reach of supplies of water and food. A corral was built for each race with walls oflava I meter high. At San 
Pedro Cove, where the Cerro Azul tortoises were to be held, an old corral was found and improved. We 
can only speculate about who built it long ago to house tortoises before loading them on to their ships -
naval vessels? whalers? settlers? Twelve tortoises were brought there while sixteen from Sierra Negra were 
taken to an improvised corral further up the coast. 
Transporting these heavy animals to the coast under the equatorial sun was a major problem. There was 
no suitable equipment to meet such an emergency. They were carried on the shoulders of two or four Park 
Wardens (depending on their weight) suspended by ropes, ventral side up, from freshly cut tree trunks. 
Unfortunately two sub-adult tortoises died from the heat during the slow trek. In the event, owing to the 
combined exertions of all the various gallant fire-fighters, the flames never reached the tortoise areas; but 
the evacuation of a number of each sub-species to a safe place provided a nucleus to guarantee their 
survival if the worst happened. Once the fires had been extinguished the tortoises were returned to their 
usual habitat. 
The other reptiles of southern Isabela seem to have escaped with relatively little damage. The snakes 
(Alsophis), lava lizards (Tropidurus) and geckos (Phyllodactylus) are more commonly found on the lower 
slopes of the volcanoes while the fires raged most fiercely at the higher elevations and even inside the 
caldera of Sierra Negra. The great Land Iguanas (Conolophus subcristatus) were never in real danger as the 
present habitat of the tiny population, which is all that remains of the once numerous colonies, was 
separated from the fire by the huge lava flow formed by the 1925 eruption. The threat to the iguanas comes 
from the dogs, pigs and cats introduced by man. But for the dedicated intervention of the herpetologist, Dr 
Dagmar Werner, and the captive breeding and repatriation programs of the Darwin Station and the 
National Park Service, there would probably be no Land Iguanas at all in southern Isabe1a. Even with the 
success of the captive breeding project, the outlook is still full of difficulty and uncertainty. 
But let us at least be thankful that the reptiles suffered as little as they did from the devastating fires. As for 
the rest of the flora and fauna, only time will show the extent of the damage. The fires aroused an 
unprecedented amount of world-wide concern for Galapagos wildlife. If only this undoubted sympathy 
could be paralleled by a comparable volume of financial support! 
8 
Noticias de Galapagos, vol. 44 1986


The giant tortoises and the great fire on Isabela

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The giant tortoises and the great fire on Isabela

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