Tourism, over-population and overfishing have become the blight of the Galapagos Islands that inspired Darwin. Now the UN is sounding the alarm.

The threat is growing to the cradle of evolution. Crucial talks take place today over the increasingly precarious future of the Galapagos Islands, whose unique wildlife inspired Charles Darwin's revolutionary theory.

High-ranking United Nations officials will be meet ministers from the government of Ecuador, which owns the volcanic islands 600 miles off its Pacific coast, to discuss how to protect them from the increasing threats posed by immigration, mass tourism, development, overfishing and the invasion of alien species.

The archipelago was the first location in the world to be declared a World Heritage Site by Unesco, the UN's cultural body - 30 years ago - and on the agenda for today's meeting in Quito, the Ecuadorian capital, will be the question of whether it should be placed on the official list of World Heritage Sites in danger.

Such a listing would be an unmistakable warning signal to the international community that one of the world's most cherished ecosystems - and historical landmarks - was in deep trouble.

Leading Unesco officials, who have spent the past four days on the islands assessing the problems at first hand, will be meeting Ecuador's ministers of Foreign Affairs, Environment and Tourism today to discuss how their conservation can be managed in the future. It is likely that they will receive a sympathetic reception, because on Tuesday, Ecuador's left-leaning President, Rafael Correa, himself declared that the islands were "at risk". His explicit recognition of the threat is regarded as a major step forward.

President Correa, an ally of Venezuela President, Hugo Chavez, who has called a referendum on a new constitution for the country on Sunday, said that some of the thousands of tourism permits issued each year might have to be suspended. "We are pushing for a series of actions to overcome the huge institutional, environmental and social crisis in the islands," he said after signing an emergency decree to help the archipelago.

The major difficulty is that what is ordained in Quito is not necessarily followed on the islands, which straddle the equator and where the population has surged from 2,000 people in 1960 to 30,000 now. The recent incomers- a large proportion of them there illegally - depend for their livelihoods on expanding tourism and fishing, and there has been fierce local resistance to conservation measures and clashes with the Galapagos national park.

Two years ago, for example, an attempt to enforce a limit on sea-cucumber harvests - worth $3m (£1.55m) annually - angered Galapagos fishermen, who threatened park rangers with petrol bombs, and in one incident took 30 scientists and a number of the islands' unique giant tortoises hostage.

The tortoises, which can live to be well over 100 years old, were among the large number of unusual animals and birds, endemic to the islands and most of them quite unafraid of people, that Charles Darwin encountered when he arrived as the young naturalist aboard HMS Beagle in 1835.

They include marine iguanas, flightless cormorants, and in particular 13 separate species of finch (including the Galapagos woodpecker finch, the only bird that uses a tool). Darwin realised that these 13 separate species had probably originated in a single species that had arrived on the islands from the South American mainland many thousands of years earlier, and as a direct result began to conceive his theory of evolution by natural selection (published in The Origin of Species in 1859).

The islands are thus doubly special, environmentally and historically - as a reservoir of remarkable species (also including sea lions, dolphins, turtles, sharks, penguins, albatrosses and many other seabirds), and as the cradle of the theory of evolution. This heritage faces four main threats, according to Marc Patry, a Unesco Galapagos specialist. They are: illegal immigration to the islands, pushing numbers of people beyond what they can sustain (up to 20 per cent of the population is believed to be there illegally); difficulty in applying the laws, so that conservation measures in place are ineffective; illegal fishing, including shark-finning, in which the fins are cut off sharks for shark's fin soup in Asian restaurants (14 species of sharks in the islands are considered under threat); and the introduction of alien plant and animal species.

Island ecosystems, which have spent millions of years developing in safety, have shown themselves particularly vulnerable to introduced species. Five of the eight native bird species on the Pacific island of Guam, for example, have been wiped out by the accidental introduction after the Second World War of the brown tree snake from Australia. The risk of invasive species is very much on the mind of Graham Watkins, the executive director of the Charles Darwin Foundation (CDF) research station on the islands, which advises the government of Ecuador, and is part-funded by the UK Government. "There are numerous dangers to the Galapagos from alien species," he said yesterday. "Some we have already learned to manage effectively - like goats. But others have only recently come in, like a bird's nest parasite which is affecting some of Darwin's finches." There are now 748 species of introduced plants in Galapagos, according to the CDF, compared to the 500 species of native plants.

Sixty percent of the 180 plant species unique to the islands are considered threatened according to the World Conservation Union Red List of Threatened Species. There are now at least 490 species of insects introduced and 53 species of other invertebrates; 55 of these have the potential to cause severe impacts on native biodiversity. Marine resources including lobster, sea cucumber and grouper have declined precipitously.

The CDF said: "Tourism visitation has grown in Galapagos from 40,000 in 1991 to over 120,000 in 2006... This rapid economic growth has been coupled with a similar rise in immigration, outstripping the capacity of management authorities... including the National Institute of Galapagos, the Galapagos National Park, the Galapagos Inspection and Quarantine System and the Municipalities."

Dr Watkins warmly welcomed President Correa's declaration and decree. What was needed, he said, was to create a sustainable society in the islands, by building stronger local institutions, ensuring that all businesses were truly sustainable - environmentally, socially and economically - and by reforming the local education system, to help people live on the islands and be employed in businesses that are linked to conservation.

The broadcaster Andrew Marr, the president of the London-based Galapagos Conservation Trust, said yesterday: "It's going to come down to how it can be made possible for local fishermen and hoteliers to live a decent life... without the islands being further increasingly developed. And it will be a question of finding ways to ration tourism in the end."

The Unesco delegation, which consists of Kishore Rao, the deputy director of the World Heritage Centre, Tumu te Heuheu, the chairman of the World Heritage Committee, and Berndt von Droste of the World Conservation Union, will report back from today's meeting to the World Heritage Committee in Christchurch, New Zealand, at the end of June, where a decision will be taken as to whether or not to put the Galapagos on the danger list.

The islands were discovered by chance in 10 March 1535 when the ship carrying Fray Tomas de Berlanga, the Bishop of Panama, stalled after the winds died and strong currents carried him out to the Galapagos. In his account to the Holy Roman Emperor Charles V, Berlanga described the harsh, desert-like condition of the islands and their giant tortoises, as well as the marine iguanas and birds. He also noted the remarkable tameness of the animals that continues to thrill and delight modern visitors - unfortunately now, too many of them.
(By Michael McCarthy, The Independent, 12/04/2007)