The Turks and Caicos Islands, a British commonwealth of roughly 30 islands in the Caribbean, occupy a small piece of paradise. The isle of Dellis Cay, for instance, is a sanctuary for local sea birds that live there year-round and an important stopover for migratory birds that fly across its miles of sandy beaches. But the flamingos and herons are getting some human neighbors in a development dubbed The O Property Collection: pricey residences by a flock of big-name architects including Shigeru Ban, Kengo Kuma, and Zaha Hadid. For many observers, the project raises troubling questions about sustainability.

Created by the Turkish businessman Cem Kinay, the development features 124 private villas, 154 residences, a Mandarin Oriental hotel, and a marina located on a 35-acre beachfront site. Residences will range from $2 million to $20 million and are aimed at those looking to purchase their third and fourth houses. The development broke ground in January and is slated for completion at the end of 2009.

For her residence, “Villa B,” Hadid has designed a geometric concrete roof that shelters a glass-walled house below it. Kuma is building canopies under luscious jungle trees to create spa villas with an inside/outside experience. Carl Ettensperger, Piero Lissoni, and Chad Oppenheim are also designing for the development. While all of the houses express the vision of their unique architects, each aims to incorporate the existing landscape.

“The original idea was to make a paradise without the buildings modifying the feeling of being in a paradise,” says Lissoni, who designed 24 hotel residences and nine beach houses for the Mandarin Oriental, as well as nine private villas. “The development was designed with a maximum respect for nature.”

But some observers take issue with this claim. Kinay purchased the previously uninhabited island from the Turks and Caicos government. In order to preserve a bird sanctuary, officials limited development to only 20 percent of the 560-acre isle. Still, any construction does have potential to create problems. “It can harm birds and make them vulnerable because, with people, there are also usually cats, mice, and rats—all of which wreak havoc on bird colonies,” says Greg Butcher, Audubon’s director of bird conservation. “The act of construction can also cause a disturbance to a wooded area where songbirds live. And new buildings can kill migrating birds, which fly into glass walls that are built in their paths.”

While none of the buildings are going for LEED accreditation, sustainable design features include photovoltaic arrays to produce electricity for the entire development; recycling the island’s limited fresh water sources; and using locally sourced wood, teak, and stones. Large overhangs for cooling, cross-ventilation, solar-heated water, an insulating green roof, and a rooftop pool that doubles as a rainwater collection tank will be a part of the resort’s master plan. In addition, air conditioning will be deployed minimally and the architects studied wind and sun patterns to determine the best orientation for cooling and heating buildings.

To lessen the impact of building on sand, which causes beach erosion, Oppenheim opted to raise his eight villas into the tree canopy. “Their elevated position allows for them to have little impact on the ground plane,” he explains. “The tree-top villas are precisely arranged on their parcels to maximize their [sustainable] and experiential qualities, channeling prevailing winds to cool the interior spaces as well as framing sunrises, sunsets, and the path of the moon on either side of the structure.”

Another green element is that no cars will be used on the island. Still, travel to the destination itself poses larger questions about sustainability. Aside from the carbon generating during construction, most houses will serve as only part-time residences for their owners—many of whom will be flying long distances to visit, generating more carbon than might be saved by using a few solar panels.

“We think that if a new development is going to be built, the greener the better. But on the other hand, you have to look at the total cost—which is there are environmental impacts to developing places that haven’t been developed before,” says Josh Dorner, a spokesperson for the Sierra Club. “It becomes a little tricky when people have this as a holiday home and they use quite a bit of carbon to visit it a few times a year.”

Lissoni responds, “The problem with pollution that comes from travel is a problem for all of society. We did the best that we could to keep the design for the island as natural as possible.”

Yet some project elements are less than environmentally sound. The marketing and press materials, for instance, spare no expense: the kit is wrapped like a gift in a box with a ribbon and arrives in a thick paper shopping bag. Included in the package is a booklet made out of a thick glossy cardboard and a series of thick glossy paper fact sheets, both non-recycled materials that could be difficult to recycle.

Even some of the architects are downplaying the sustainable qualities of their contributions. Ban, for instance, designed a beachfront village and an over-water villa for 15 different parcels. Dismissing the concept of sustainability as being “too fashionable,” he says that he approached the project more pragmatically. Given the scarcity of local construction workers, his beachfront house borrows from his earlier experimentation with modular, prefabricated containers. While the system gives homeowners the flexibility to move the boxes around, Ban sees a downside. “It is difficult to work on this kind of project in which I don’t see the particular client who will live in the house,” he says.