e're hurling along the swells in a small, narrow boat, plunging with every trough, the engines churning and the waves pounding hard. When the crests lift us I can see for miles, but there's no land visible, just 360 degrees of angry black-blue water under the first sunlight.
It's not an easy voyage, but my companion, Tukirin Partomihardjo, a botanist at the Indonesian Institute of Sciences, reassures me as only a scientist can. Many others have made this journey, he tells me -- many lesser species, far less well equipped.
We're heading for Krakatau (known to many westerners as Krakatoa), in the middle of the Sunda Strait between the major Indonesian islands of Java and Sumatra.
This minor archipelago is all that remains of the formerly towering volcano of the same name. In 1883, Krakatau erupted with a violence nearly ten thousand times that of the Hiroshima bomb. A shock wave blew around the globe. Nearly 40,000 people died. When the dust settled, the small islands left behind were buried in as much as 130 feet of ash. Life had been extinguished and organic matter sterilized by the intense heat. There were no seeds, no topsoil, and certainly no wildlife.
Yet in the decades since, despite the forbidding journey across the strait, terrestrial nature's abundance has returned to Krakatau.
ndonesia is a country rife with bad news. Its political system has been gripped by tyranny and corruption for decades. Environmentally, over the past half century, it has dispatched a grave assault on nature, soiling rivers, bombing and poisoning coral reefs, and tearing down vast expanses of tropical forest.
Meanwhile, on Krakatau, nature has methodically healed itself. Though the ancient forests that probably existed before the eruption have not returned, the islands are green and thriving, and have become a world-renowned natural laboratory for studying tropical flora regrowth. They stand as evidence of the environment's resilience -- testimony that if people can only leave a place alone and unpoisoned, nature will tend to its glorious garden.
How did the islands return to life? Most mountain flanks cleansed by fires or volcanoes can be reseeded by nearby forests; here were sterile islands, some 25 miles from the coast, that now harbor non-seafaring species as small as ants and fragile as orchids. Fortunately, nineteenth-century biologists launched a series of expeditions to the remnants of Krakatau, particularly to Rakata, the biggest island. Since 1981, Tukirin has followed in their footsteps.
After we've tossed on the surf for nearly an hour, Tukirin points to a faint silhouette in the distance. Slowly, the islands fade into view.
First, we approach Anak Krakatau, a volcanic cone that rose from the sea in 1930 and has remained active since. Regular eruptions extinguish life from its smooth, black sides. A fringe of sparse forest stands on the only part of the island beyond reach of the eruptions. Tukirin and I scramble up Anak's frying-pan-hot flanks. The rubble is dry, coarse, and forbidding, punctuated every few feet by jagged boulders. When the first expedition arrived in Krakatau, just a few months after the eruption, no sign of life was found on the black slopes, which must have looked much like these. Nine months later, scientists found one lonely spider, spinning a web. How did it get there? At some point in their lives, many spider species spin a sail and fly long distances on the wind. This one happened to land on solid ground rather than in the sea. But without prey, it almost surely starved.
In big moon-steps, Tukirin and I slide back down Anak Krakatau. Near the bottom, we cross a low slope colonized by five-foot lime-colored shoots of sugar cane grass. Tukirin points out four-inch casuarina saplings and miniature ferns hiding by boulders. After that first solitary spider, these were the pioneer species. Some seeds, like the casuarina's, can float unharmed for miles. Others, like the orchid's, must have traveled the strait on a swift breeze. Tukirin shows me a melastoma bush, whose bright berries are a treat to birds; the seeds pass through the bird's gut undigested and, with a little luck, take root where its guano lands.
The highly efficient pioneer species -- flora that thrive with little water and few nutrients -- paved the way for tiny herbivores: caterpillars, ants, and insect larvae, which probably arrived on driftwood. The insects were food for the next spider that parachuted in. When the grasses died, their humus supported a second generation of flora.
Boarding the boat again, we head for Rakata. Here, only six years after the eruption, scientists found spiders, flies, beetles, and butterflies among the pioneering flora; they even spotted a large monitor lizard that had probably swum to the island. Within two decades, a woodland had returned, with trees more than 40 feet tall draped in vines. There are now multiple species: 400 vascular plants, 54 butterflies, 30 birds,18 land mollusks, 17 bats, and 9 reptiles. We cruise past cliffs covered in the rich green of a tropical moss forest -- trees, climbers, and stranglers competing for space and sunlight.
What Krakatau and other recovered ecosystems show us, says the biodiversity expert E.O. Wilson, is that on a local scale, "the biosphere is capable of rapid self-healing." But there are two conditions, he adds. First, people must leave the place alone. Krakatau's isolation is not absolute -- Tukirin shows me chili pepper plants and a mango tree on the beach at Rakata, likely the fruits of fishermen's picnics -- but it is strictly protected as a nature preserve within a World Heritage Site. Second, natural ecosystems must survive close by. After Krakatau exploded, nearby forests contributed the diversity of recolonizing species. Here is the bad news: Now that Java is almost completely deforested, Tukirin tells me, Rakata would look very different if the regeneration were to happen today.
Still, hiking through a forest that has come back from the dead, I can't help feeling optimistic. Rakata tells a remarkable story about the restitching of the web of life. Tukirin stops under a fig tree; the island supports as many as ten species. He explains that the tree cannot reproduce without the help of a particular type of bird and a particular type of wasp. The bird disperses the seeds, and the wasp pollinates the flower. Complicating matters, the wasp lays its eggs in the fruit, so it cannot reproduce without the tree. How did the bird, the fig, and the wasp manage to meet here at the right time? How did the wasp, tiny as a pinhead, find this small, distant island during its brief existence? That, Tukirin says, is the mystery of life.