Tightened U.S. rules on dealings with Cuba are reducing contacts between American and Cuban scientists who want to study and preserve the island's treasure of flora and fauna.

BY GEORGIA TASKER

The hoary old-man palm, a nearly extinct cycad, the curious belly palm, the world's smallest hummingbird, a kapok relative that grows on the sides of limestone cliffs -- these unique plants and animals make Cuba, the largest island of the Greater Antilles, a biological treasure trove.

Half of the island's 6,700 species of plants are found nowhere else, even within the greater Caribbean region -- which claims only 12,000 plant species in all.

So dazzling are Cuba's flora and fauna that despite the four-decades-old U.S. embargo, a cadre of American scientists has been working quietly for years with their Cuban colleagues, racing to protect as much as possible before the natural splendor butts heads with resorts and condominiums.

This scientific cooperation has been growing for a decade, as Cuba began to allow more scientists into the country and the United States permitted more scientific exchanges.

But recent Bush administration restrictions on travel to Cuba are reducing the flow of information once more. Scientists no longer can go for a few days to collect plants or consult with colleagues -- they must stay for 10 weeks. They can't spend more than $50 a day, so renting a car may prove impossible. And a separate, specific license must be obtained if a research scientist wants to collaborate with a Cuban counterpart.

WHAT THE RULES ALLOW

Molly Millerwise, a Treasury Department spokeswoman, said the new rules will allow a trickle of exchange.

''An accredited university can apply to have 10 weeks in Cuba, and when licensed, it can engage in research,'' she said. ``That includes having a scholar come up to the U.S. and teach. Cuban nationals under this license -- they can teach, and the university can pay them for it.''

But the landscape has clearly changed. The rules make it ''much more difficult for people to engage in legitimate scientific research,'' said John Croatsworth, director of Harvard University's David Rockefeller Center for Latin American Studies.

Mike Maunder, director of Fairchild Tropical Botanic Garden in Coral Gables, said the garden has suspended its Cuba research because of the restrictions.

Brad Bennett, an ethnobotanist at Florida International University who made his first trip to Cuba this year, said FIU was not sure what the restrictions would mean to its researchers.

Scientists, including those from FIU and Fairchild, are awed by the plant life they have seen in Cuba.

''I was surprised at how much diversity there was,'' Bennett said. ''On the eastern end, it was just mind-boggling.'' Bennett calls the island ''a palm paradise,'' and Fairchild and FIU have focused on ways to save nearly extinct palms.

Ties between biologists in the United States and Cuba reach back at least to 1899, when sugar-cane grower Edwin Atkins asked Harvard for help with his crops. In 1902, Harvard set up an agricultural research center, which became the Harvard garden. It was taken over by the Cuban government after the 1959 revolution, which curtailed U.S.-Cuban botanical cooperation, and is now the Cienfuegos Botanical Garden.

FOCUS ON TOURISM

After the Soviet Union ended its financial subsidies to Cuba in 1989, there wasn't enough money for food, much less plant science. President Fidel Castro switched his focus from biotechnology to tourism, to bring money to the island quickly.

For the biotechnology people, scientific journals were stopped and computer use was restricted. By the late 1990s, some frustrated biotech scientists had left.

In the 1980s, international conservation groups began to focus on conservation in the Caribbean, where intense agriculture and growing populations had put a severe squeeze on natural areas. Two conferences in the mid-1990s, organized by the David Rockefeller Center at Harvard, further raised scientific consciousness about the importance of Cuba's environment.

As more U.S. scientists traveled to Cuba, they found 85 endemic palms, two dozen native begonias and distinctive pine forests. They also found a cadre of Cuban biologists who had been well trained in Russia and East Germany but had few resources.

''Almost everything is done on a shoestring because a shoestring is all they have,'' said Bob Dressler, a Central Florida orchid expert who attended a conference at the Soroa Orquideario in 1997, then drove across Cuba, looking for orchids. Cuban botanists who went along were ''delighted to have someone who could buy the gas for a field trip,'' he said.

Andrew Guthrie, a U.S. citizen who heads the Queen Elizabeth II Park on Grand Cayman Island, found a shortage of such basics as gardening hand tools in 1995. ''So we left them our trowels,'' Guthrie said.

When Missouri Botanical Garden's Shirley Graham worked there last year on the Flora of Cuba, she took along newspapers for pressing plants in the field.

INTERNET HELPS

The island's flora are so rich that scientists hope to do what they can to work within the narrow limits of the new restrictions.

The Internet is proving to be an important medium for information exchange.

''Their journals are old and difficult,'' said Brian Boom of the New York Botanical Garden.

"So one of the ways we are trying to bridge that [gap] is to get high-resolution digital images of specimens and put them on the Web.''