I met Makana in August 2005, where an old lava flow meets the ocean in a series of ledges and tide pools on Kauai, one of the Hawaiian Islands. He was a “local” of about my age who got his name (Hawaiian for “gift”) from the old volcano that formed the backdrop of our introduction. He wasn’t in college, but had a good job as a caddy at an upscale golf course, where Bill Clinton had tipped one of his buddies well the day before. In the afternoons, he and his friends came to this spot — still called “The Queen’s Bath” decades after the days of Hawaii’s royal rulers — to “talk story” and swap tales with an endless stream of tourists. They smile and joke, even as we talk about local crises in health care, drug abuse and housing prices driven so high by outside demand that local sons and daughters don’t know how they’ll afford a place to live.

As we chatted, one young man abruptly dove off a 20-foot cliff into the turquoise water below. He swam rapidly across the cove in pursuit of an enormous green sea turtle — perhaps 5 feet in length — which glided just out of his reach for several meters before turning gracefully on a flipper and rapidly outdistancing him. Giving up on the chase, he climbed out of the water and back up to the ledge with a smile on his face. He’d been playing this game with that particular turtle for several years, he explained. “One day, I will catch him, but for now the old man likes to joke with me.” His friends only laughed.

I saw the process repeated several times that day. The turtle was never caught, and I had little fear for it. Elsewhere, green sea turtles (which are listed as an endangered species) are crowded, chased, encircled and petted by dozens of eager snorkellers. I was no less guilty, having pursued more than my fair share as a child. There was something different about how these young men saw that turtle, though. It was a companion, perhaps a friend, another living, feeling being with whom they shared an increasingly fragile world.

Hawaii is a state under siege. About 70 million years ago, a hot spot at the ocean’s floor began to build the islands one by one. They broke the surface as active volcanoes, spewing ash and lava to create a platform of bare rock for the first seeds of life. These seeds were few and far between: They had to survive a 2,500-mile trip from the closest continent across an unforgiving Pacific Ocean and then carve a niche for themselves on the most unforgiving of surfaces. As millennia went by, soil formed and lush tropical rainforests, swamps and coral reefs emerged.

Isolated from the mainland, the few species that arrived could evolve and diversify into dozens of new forms, unhindered by the predators or competitors they’d left behind on their continental homes. A thousand “ancestral colonists” gave rise to thousands of plants and insects, a striking diversity of birds (including an array of honeycreepers that rival Darwin’s finches) and one lone mammal: the Hawaiian bat. Most of these species (including 89 percent of the native plants) are endemic (found only in Hawaii) and some are confined to a single island. Even the slightest damage to their miniscule habitats could mean extinction.

Threats, of course, abound. There are the usual suspects: habitat loss to agriculture, industry and the latest resort, damage from overuse, death by over-hunting. Perhaps the most significant problem today, however, is species invasion. Transported to Hawaii from all over the planet, these foreigners take advantage of sheltered and defenseless natives to thrive within weakened ecosystems. The very icons of the islands — coconut palms, pineapple, sugar cane, pigs roasted at luaus, flowers for leis — are all introduced. Tropical forests have been uprooted by wild boars, the eggs of native birds have been devoured by rats and mongoose, and countless tourists have been swarmed by newly introduced mosquitoes.

Today, while we may understand the risk of invasion far better, we are more likely than ever to invite it. Our globalized world has created numerous vectors for transplantation: ships and airplanes bear cargo and hitchhikers between previously unconnected areas. Yet living without the trappings of modern life seems unthinkable: who can turn down papayas in December, or cheap Halloween costumes manufactured overseas?

But maybe Makana, his friends, and their laughter at the edge of the sea hold a deeper lesson for all of us. There are some things more important than globalization, efficiency and dollars. There are the things we respect, the lifestyles we love and a world we can’t afford to lose. The silhouette of a sea turtle, the sweet song of a honeycreeper — the gifts of the islands.

Holly welcomes reader feedback, commentary, island stories, and critical review of turtle behavior at hollyvm “at” stanford “dot” edu.