Environmental groups have banded together in a last-ditch bid to save rare mushrooms, mosses, orchids, ants and bumblebees from three proposed housing developments in the Cairngorms National Park.

Fourteen groups have written to Scottish ministers urging them to block the building of 73 houses in Carrbridge and Nethy Bridge because they will destroy precious wildlife sites. They want the developments to be deleted from the latest version of the Cairngorms local development plan.

Among the rare wildlife under threat are crimson waxcap mushrooms, green shield mosses, frog orchids and fungi found on pinewood orchids known as creeping ladies' tresses. Ancient woodlands and flower-rich grasslands vital for mountain bumble bees, wood ants and other insects are also at risk, the groups say.

"We are requesting these ­particular housing allocations be removed from the local development plan because significant new information has revealed their exceptional value for wildlife," said Ian Lawson, director of the Cairngorms Campaign, which co-ordinated a joint letter.

"We simply cannot afford to continually eat away at our most precious countryside if we are to leave a national park worthy of the name to future generations."

One signatory was Woodland Trust Scotland, which pointed out that the Cairngorms National Park contained some of the finest native woodland in the UK. "We are very concerned that the local development plans for the park leave a number of areas of ancient woodland dangerously exposed to development, against national planning policy," said the trust's director, Carol Evans.

"Ancient woodland is an irreplaceable habitat that has developed over many hundreds of years and supports a rich variety of rare wildlife. Any further loss of ancient woodland is unacceptable, particularly within our national parks."

Other groups backing the call included the Scottish Campaign for National Parks, Ramblers Scotland, the Scottish Wild Land Group, the North East Mountain Trust, Buglife Scotland and Friends of the Earth Scotland. "We believe we should be standing up for our highest quality countryside and safeguarding its irreplaceable and exceptional biodiversity," said Gus Jones, convener of the Badenoch and Strathspey Conservation Group.

Environmental group Plantlife has written separately to the Scottish Government, pointing out that the mushrooms, mosses and orchids threatened by the Carrbridge and Nethy Bridge housing schemes could not be recreated elsewhere.

Murray Ferguson, director of planning and rural development at the Cairngorms National Park Authority, stressed that the local development plan had been through a long and inclusive consultation process. "All unresolved objections to the plan have been considered by Scottish Government reporters, and we have accepted their recommendations and have submitted the proposed plan to Scottish ministers," he said.

A Scottish Government ­spokesman said: "The Cairngorms National Park Authority gave notice of their intention to adopt the Cairngorms local development plan on December 5. As it is now with the Scottish ministers for consideration, it would be inappropriate to comment on the content of the plan."