Sir David Attenborough, Bill Oddie and Chris Packham are supporting an effort to save the orangutan from extinction by raising £1m in just two weeks.

Orangutans in their natural environment live in undisturbed ancient forests and for many years it was believed they shunned any other habitats. But researchers have discovered they can survive just as well and perhaps even better in forests that have been intensively thinned out by loggers, giving renewed hope for the species.

Conservationists have now devised a project that they hope will ensure the long-term survival of orangutans by protecting key patches of secondary forest – areas that have been stripped of the biggest trees but are still wooded – from being chopped down for palm oil and other types of agriculture.

By aiming for £1m in donations in a two-week campaign from 2 October to 16 October, they hope to raise enough money to buy and protect small lots of secondary forest that will link different populations of the primate. Three wealthy backers of the charity behind the project, the World Land Trust, have promised to double any donation made during the fortnight up to a maximum of £500,000.

Sir David Attenborough said: "Every bit of the rainforest that is knocked down is less space for orangutans. They have been reduced very seriously in the past decade, and we must do all we can to reverse this devastation. I fully support World Land Trust in its bid to save this important land."

Bill Oddie, the conservationist and broadcaster, visited Borneo recently and was struck by the sight of palm oil plantations, which have replaced much of the original forest and orangutan habitat.

He said the sight emphasised the need to protect "wildlife corridors", which allow orangutans and other animals to travel between sections of forest that are otherwise surrounded by cultivated land. "These corridors have got to be as good as the forest. The palm oil plantations are useless to them," he added.

Asked why effort should be put into saving orangutans, he said: "Wildlife does add immensely to the human experience, quite apart from what you might think of the morality of welfare of animals. It's a better world with them."

Chris Packham, the BBC wildlife presenter, welcomed the project as a means of saving not just the orangutan but other rare animals such as pygmy elephants.

He said orangutans are "absolutely extraordinary animals", adding: "When you look into their eyes it's like a reflection in a not so distant mirror."

The campaign has been boosted by the support of advertising executives who have designed an advertisement for free and plan to run it without charge, starting last Saturday in Condé Nast magazines, including Vanity Fair, and the Independent.

While there are 54,000 orangutans estimated to live in Borneo, and a further 6,600 in Sumatra, the species is under threat of extinction because its habitat has become fragmented by the encroachment of agriculture.

The project is led by Isabelle Lackman, a French biologist who has devoted her life to studying orangutans since the 1990s when she moved from Paris to Borneo.

Dr Lackman, the president of Hutan and director of KOCP, dismissed warnings by some conservationists that orangutans could disappear in 20 to 30 years as ridiculous but said the threat was nonetheless serious: "If things don't improve orangutans will disappear in the medium term – probably in a couple of hundred years."

"A total of 54,000 would seem a lot but it's fragmented. There are hundreds of smaller populations. That's the main problem for the survival of the species. That's what we are trying to address with the World Land Trust."