Pasific Island Flora

Pasific Island Flora
Pasific Island Flora

The vast region of the Pacific Ocean collectively called Oceania holds thousands of islands. Oceania spreads across the Pacific from 20 degrees north latitude to 50 degrees south latitude and from longitude 125 degrees east to 130 degrees west.

The major groupings of islands are Melanesia, Micronesia, Polynesia, and New Zealand. Melanesia (“black islands”) is a group of large islands immediately north and east of Australia, from New Guinea to New Caledonia.

Micronesia ("little islands") is made up of hundreds of tiny atolls in the western Pacific. Polynesia ("many islands") covers a huge region in the central Pacific. New Zealand lies east and south of Australia.

For botanical purposes, these islands can be categorized by climate and formation type. Climates range from tropical to sub-Antarctic, dry to very rainy. Types include volcanic (Fiji, Guam, and Hawaii), tectonic (New Zealand and New Guinea), and low coral atolls (nearly all of Micronesia’s islands).

Unique Ecosystems

Organisms have a hard time reaching islands across the broad expanses of the Pacific Ocean. The islands’ isolation leads to trends in the number of species on any given island. Bigger islands have more species; those farthest from continents have fewer species.

To reach the islands, plants must be carried by animals or rely on wind or water currents. Birds are usually the first visitors, bringing with them hitchhiking insects and plant seeds in their digestive tracts.

Island plants and animals evolve together, affected by difficult conditions. Soil is often poor and food limited. Harsh environments and isolation contribute to the formation of new and unique species.

Island ecosystems are sensitive to disturbances, whether from natural causes, such as severe storms, or human activities, such as construction, agriculture, logging, and introduced species.

Introduced species (exotics), both accidental and deliberate, are a serious problem.Rats and feral animals (domestic animals that have gone wild) can devastate island ecosystems. Pigs, rats, and goats are particularly devastating to vegetation.

Introduced plants may overgrow native ones. Exotics also bring diseases or other problems to which native plants and animals have no resistance. For example, a Hawaiian bee crawls headfirst into native, barrel-shaped flowers, gathers the nectar, and then backs out.

A plant that was introduced in Hawaii by landscapers attracted bees, but the flowers were smaller than those of the native plants. Once a bee crawled in, it became stuck like a cork in a bottle. This led to thousands of these plants, each with hundreds of flowers, becoming stoppered with dead bees.

Many tropical and temperate islands have coastal wetlands and mangrove swamps growing at the edge of the sea. Mangroves are low-growing, salt-tolerant trees that form dense tangles virtually impenetrable to humans.

Wetlands and mangrove swamps are important breeding grounds for many types of fish and crabs and also trap sediment, stabilize shorelines, and protect coastlines from storms. When humans fill in the wetlands and cut down the mangroves, it causes coastal erosion and the loss of food fish.

Fiji Islands

Fiji island flora
Fiji island flora

The Fiji Islands are mostly volcanic in origin and lie in the South Pacific Ocean between longitudes 175 degrees east and 178 degrees west and 15 degrees and 22 degrees south latitudes, about 1,300 miles (2,100 kilometers) north of Auckland, New Zealand.

Some parts of the islands receive up to 13 feet (4 meters) of rain per year, while other parts remain dry. A range of volcanic peaks divides the islands. The differences in weather and elevation create a variety of habitats—dense rain forests, grassy savanna, and mangrove swamps—and a large diversity of species.

Human disruption on Fiji has been moderate. About half the total area is still forested, and less than one-fourth of the land is suitable for agriculture. Trees include mahogany, pine, pandanus, coconut palms, mangoes, guava, and figs.

Banyan figs are difficult to cut down and are responsible for some of the lack of forest clearing. The figs are an important food for many birds and animals. Other rain-forest plants include orchids, ferns, and epiphytes (plants that grow upon other plants).

There are nearly fifteen hundred endemic Fijian plant species, including ten species of palm tree on the island of Viti Levu. Grassy savannas are found higher on the volcanic slopes and in the dry zones. They are often planted with coconut palms and taro, a plant with potato-like tubers that grows on many Pacific Islands.

There are twelve reserve areas in the Fijian islands, but several are being logged and provide little sanctuary to native plants and animals. The government is interested in increased logging of mahogany and pine. The Fiji Pine Commission hopes to encourage the development of pine forests.

Pines grow quickly and could form a sustainable logging industry, unlike the valuable but slow-growing mahogany trees. Increased world interest in herbal remedies has created a market for Fiji’s traditional crop, kava root, and for ginger processing.

The University of the South Pacific is located in Fiji and is a center of serious research into South Pacific species. Tourism is important to Fiji’s economy and, with management, could be a source of income to Fijians while preserving native wildlife.

New Guinea

New Guinea flora
New Guinea flora

The world’s largest tropical island, New Guinea is located north of Australia, just south of the equator. It is tectonic in origin,with large changes in elevation and many different habitats.

Because of its size and varied terrain, New Guinea has a greater variety of habitats than any similar-sized land area in the world. In fact, New Guinea is so rugged that it is one of the least explored or developed places on earth. It provides the best remaining example of the types of organisms that can develop in island isolation.

New Guinea habitats include cold tundra, tropical rain forests, grassy savannas, coastal zones, montane rain forests, cloud forests, and bogs. There are at least twenty thousand species of flowering plants, including more than twenty-five hundred species of orchids, and hundreds of birds and animals. Many New Guinea species are unusual.

Endemic Klinki pines are the tallest tropical trees in the world, reaching 295 feet (90 meters) tall. Many forests host “ant-plants,” warty looking epiphytes that have hollow mazes inside their tissues. Ants live in the maze, safe from predators. The ants provide nutrition for the plant in the form of droppings, scraps of food, and dead ants.

Even though New Guinea is rugged and isolated, human impact is increasing. The population is rising, which means that more forests are being logged and grasslands plowed for agriculture, roads, and development.

Humans have brought in food plants such as the sago palm, which can be cultivated in areas where traditional crops will not survive. They also cultivate pandanus trees, several varieties of fruiting vine, breadfruit, fungi, tubers, sugarcane, bananas, taro, and yams. Gold, silver, and copper have been discovered, which encourages destructive mining.

It has proven difficult to develop New Guinea economically without destroying the unique life of the island. It is hoped that lessons learned on other islands, such as Guam and New Zealand, may be applied to New Guinea.

The government has tried incentives to keep wild areas wild, including encouraging ecologically friendly businesses, such as crocodile and butterfly farms and ecotourism. The National Park reserve that includes Mount Jaya is the only place in the world where it is possible to visit a glacier and a coral reef in the same park.

New Zealand

Located off the eastern edge of Australia, New Zealand has a fairly moderate climate that comes from conflicting warm, humid Pacific and colder Antarctic weather. It is similar to New Guinea, with rugged terrain, high mountains, and habitats from grassy open plains to dense forests, wet areas to near-deserts.

Unlike New Guinea, however, New Zealand has been occupied and developed by humans for hundreds of years. Before large-scale agriculture, about half of New Zealand was covered with forests and one-third with grassland communities. Now half is pasture for grazing, and one-quarter is forest, mostly introduced species.

Much of the remaining native forest is maintained as national parks and reserves. Pastureland usually consists of a single species of grass and does not support the wide variety of bird and animal life of the original grassland communities.

There are more than four thousand species of beetles, two thousand species of flies, and fifteen hundred species of butterflies and moths. In a reversal of the usual ecological concerns, some native insects are destroying introduced pasture grasses.

Coral Atolls

The Federated States of Micronesia consist mainly of small atolls. Coral atolls are found only in tropical latitudes because coral (small, colonial animals) grow only in warm water. Coral reefs support a tremendous variety of fish, crabs, and mollusks. Atolls tend to have porous, infertile soil and to be very low in elevation.

The inhabited state of Tokelau, three small islands located at 9 degrees south latitude, longitude 172 degrees west, has a maximum elevation of 16 feet (5meters). Due to the low profile, poor soil, and occasional scouring by typhoons, flora are mostly limited to hardy root crops and fast-growing trees such as coconut and pandanus.

Other vegetation may include native and introduced species such as papaya, banana, arrowroot, taro, lime, breadfruit, and pumpkin. Common fauna are lizards, rodents, crabs, and other small creatures. Pigs, ducks, and chickens are raised for food.

Human disturbances on coral atolls often have been particularly violent; several nuclear test bombs were exploded on Bikini Atoll and other islands in the 1940’s and 1950’s. Kwajalein, the largest atoll in the world, is used by the U.S.military for intercontinental ballistic missile target practice.

Johnston Atoll, about 820 miles (1,320 kilometers) southwest of Honolulu, is a U.S. military base and storage facility for radioactive and toxic substances. It is also designated as a protected area and bird-breeding ground.

Future Prospects

Island ecosystems are unique and fragile. Some, like those in Guam and New Zealand, can never be returned to their original state, but with extensive wildlife management, many native species can be saved from extinction. New Guinea, Fiji, and many smaller islands are in earlier stages of development, and wildlife destruction can still be controlled.

Conservationists sometimes do not realize that islands are not small, geographical zoos and gardens; people live there and want to improve their lives. Development cannot be stopped, but it can be managed so that the humans can improve their standard of living as they wish and the original, amazing island dwellers can still survive.