Flora and Fauna
The flora and fauna of Oceania originated in the Malaysian region; in the two regions, ecological niches are filled by similar plants. One sees a steady decline in the variety of genera as one moves east: even in distant Hawaii very few native plants have an American origin. New Guinea has more than 5,000 vegetal species, New Caledonia 3,250, and French Polynesia only 1,000. Some species such as casuarinas and coconuts were spread by means of floating seeds or fruit, and wind and birds were also effective in colonization. The microscopic spores of ferns can be carried vast distances by the wind. Later, humans became the vehicle: the Polynesians introduced taro, yams, breadfruit, plantains, coconuts, sugarcane, kava, paper mulberry, and much more to the islands.
The high islands of the South Pacific support a great variety of plantlife, while the low islands are restricted to a few hardy, drought-resistant species such as coconuts and pandanus. Rainforests fill the valleys and damp windward slopes of the high islands, while brush and thickets grow in more exposed locations. Hillsides in the drier areas are covered with coarse grasses. Yet even large islands such as Viti Levu have an extremely limited variety of plantlife when compared to Indonesia. The absence of leaf-eating animals allowed the vegetation to develop largely without the protective spines and thorns found elsewhere.
Distance, drought, and poor soil have made atoll vegetation among the most unvaried on earth. Though a tropical atoll might seem "lush," no more than 15 native species may be present! On the atolls, taro, a root vegetable with broad heart-shaped leaves, must be cultivated in deep organic pits. The vegetation of a raised atoll is apt to be far denser, with many more species, yet it's likely that fewer than half are native.
Mangroves are often found along high island coastal lagoons. The cable roots of the saltwater-tolerant red mangrove anchor in the shallow upper layer of oxygenated mud, avoiding the layers of hydrogen sulfide below. The tree provides shade for tiny organisms dwelling in the tidal mudflats—a place for birds to nest and for fish or shellfish to feed and spawn. The mangroves also perform the same task as land-building coral colonies along the reefs. As sediments are trapped between the roots, the trees extend farther into the lagoon, creating a unique natural environment. The past two decades have seen widespread destruction of the mangroves.
Sugarcane probably originated in the South Pacific. On New Guinea the islanders have cultivated the plant for thousands of years, selecting vigorous varieties with the most colorful stems. The story goes that two Melanesian fishermen, To-Kabwana and To-Karavuvu, found a piece of sugarcane in their net one day. They threw it away, but after twice catching it again they decided to keep it and painted the stalk a bright color. Eventually the cane burst and a woman came forth. She cooked food for the men but hid herself at night. Finally she was captured and became the wife of one of the men. From their union sprang the whole human race.
As with the flora, the variety of animal and bird species encountered in Oceania declines as you move away from the Asian mainland. The Wallace Line between Indonesia's Bali and Lombok was once believed to separate the terrestrial fauna of Southeast Asia from that of Australia. Although it's now apparent that there's no such clear-cut division, it still provides a frame of reference. Many of the marsupials and monotremes of Australia are also native to Papua New Guinea. Sea cows (dugongs) are found in New Guinea, the Solomons, and Vanuatu. The fauna to the east of New Guinea is much sparser, with flying foxes and insect-eating bats the only mammals that spread to all of Oceania (except Eastern Polynesia) without the aid of man.
Island birdlife is far more abundant than land-based fauna but still reflects the decline in variety from west to east. Bird-watching is a highly recommended pursuit for the serious Pacific traveler; you'll find it opens unexpected doors. Good field guides are few (ask at local bookstores, museums, and cultural centers), but a determined interest will bring you into contact with fascinating people and lead to great adventures. The best time to observe forest birds is in the very early morning—they move around a lot less in the heat of the day.
Very few land snakes live in Oceania and the more common sea snakes are shy and inoffensive. This, and the relative absence of leeches, poisonous plants, thorns, and dangerous wild animals, makes the South Pacific a paradise for hikers. One creature to watch out for is the centipede, which often hides under stones or anything else lying around. It's a long, flat, fast-moving insect not to be confused with the round, slow, and harmless millipede. The centipede's bite, though painful, is not lethal to a normal adult.
Geckos and skinks are small lizards often seen on the islands. The skink hunts insects by day; its tail breaks off if you catch it, but a new one quickly grows. The gecko is nocturnal and has no eyelids. Adhesive toe pads enable it to pass along vertical surfaces, and it changes color to avoid detection. Unlike the skink, which avoids humans, geckos often live in people's homes, where they eat insects attracted by electric lights. Its loud clicking call may be a territorial warning to other geckos. Two species of geckos are asexual: In these, males do not exist and the unfertilized eggs hatch into females identical to the mother. Geckos are the highest members of the animal world where this phenomenon takes place. During the 1970s a sexual species of house gecko was introduced to Samoa and Vanuatu, and in 1988 it arrived on Tahiti. These larger, more aggressive geckos have drastically reduced the population of endemic asexual species.
Ancient Polynesian navigators introduced pigs, dogs, and chickens; they also brought along gray rats (a few species of mice are native to Australia and New Guinea). Captain Cook contributed cattle, horses, and goats; Captain Wallis left behind cats. The bird-eating mongoose was introduced to the region in the 1880s to combat the rats. Giant African snails (Achatina fulica) were brought to the islands by gourmets fond of fancy French food. Some of the snails escaped, multiplied, and now crawl wild, destroying the vegetation. They now exist in the Samoas, New Caledonia, French Polynesia, Vanuatu, and Wallis and Futuna.
Perhaps the most unfortunate newcomer of all is the hopping common mynah bird (Acridotheres tristis), introduced to many islands from Indonesia at the turn of the century to control insects, which were damaging the citrus and coconut plantations. The mynahs multiplied profusely and have become major pests, inflicting great harm on the very trees they were brought in to protect. Worse still, many indigenous birds are forced out of their habitat by these noisy, aggressive birds with yellow beaks and feet. This and rapid deforestation by man have made the South Pacific the region with the highest proportion of endangered endemic bird species on earth.