An hour-long stroll through an oak forest, past clusters ofblackberries, St John`s wort, olive trees and butterflies, ends withthe rewarding sight of soft, white sands and gently breaking waves.

OnKaradere beach, in north-east Bulgaria, a smattering of families haveset up camp for the summer, as they have done for years. But this yearthe happy-go-lucky mood has been punctured by fears that the smallcorner of paradise is under imminent threat by Bulgaria`s firstcarbon-neutral resort.

Having been considered ripe fordevelopment since the collapse of communism 19 years ago, the area isset to be turned into a luxury €1bn {£780m} settlement. Dubbed theBlack Sea Gardens, it will include five new hill towns, artificiallakes, a marina and an extensive leisure area and will beself-sustaining, thanks to biomass power and construction from local,natural resources, say the developers.

But the 540-acre{219-hectare} development, spearheaded by the British architect SirNorman Foster, has enraged Bulgaria`s growing band of ecologists.

Theysay it will destroy the Black Sea coast`s last remaining virginstretches of beach and will have a devastating effect on the richbiodiversity of an area which has environmental protection status underthe EU`s Natura 2000 programme, which aims to protect endangeredspecies and habitats.

But the Bulgarian government`s failure toenact regulations outlawing extensive developments in such areas hasallowed coastal constructions to go ahead almost unhindered. Now thereis hardly a stretch of the country`s 220-mile coastline untouched byoverdeveloped resorts. Locals are often restricted from accessingbeaches whose entrances are flanked by security guards.

Constructionof the Black Sea Gardens project, which Foster and Partner`s websitedescribes as "a series of car-free hill towns in an unspoilt setting ofoak forests, meadows and river gorges", is due to start next year.Under the plans, 15,000 inhabitants of Sky Village, Wilderness Village,Meadow Village, Cape Village and Sea Village will be encouraged toleave their cars outside the settlements and go by foot, or use poolsof electric cars and shuttle buses instead.

Sky is the firstvillage due to be built, with the backing of a British-Bulgarianinvestment group. US, Russian and Saudi Arabian investors haveexpressed an interest in the other hill towns, according to theBulgarian co-architects, Projects Ltd, which describes the resort ashaving something for every holidaymaker - "from sportish Club Med typesto more contemplative, sleepy types".

Foster and Partners didnot provide anyone to talk to the Guardian, but in a press release itstressed that the resort is designed to blend in with its environment."The residential clusters are tightly packed and integrated into thecontours of the landscape, preserving the majority of its site asvirgin terrain," it read.

Detractors say while the plans might beof a much higher standard than the depressing array of substandardconstructions hugging the Black Sea, the sheer scale of the resort willdo lasting damage to the natural habitat. The settlements will eat intountouched oak forests, and the invasion of thousands of people and newroads will disturb one of Europe`s major migratory routes for millionsof birds, known as via pontica, they say.

"I ask myself whetherNorman Foster really knows what he`s getting himself in to," said TodorKarastoyanov, a musician and protester against the project whofrequents the beach and married his wife, Boriana, there last summer.

"Wewant to try to stop him from making the biggest mistake of his careerby building here, because it`s immoral and he might not know that."

BilianaVoutchkova, a concert violinist holidaying on Karadere beach with herfamily, as she has done since her childhood, said: "This has been amagnet for
www.guardian.co.uk/environment/2008/jul/14/greenbuilding.climatechange