Buru rainforest
The Buru rainforest, located on Buru Island in Southeast Asia, is a tropical rainforest renowned for its distinct blend of Asian and Australian wildlife. Spanning approximately 3,670 square miles, the rainforest is part of the Wallacean biogeographic zone and features a variety of unique flora and fauna, including the endemic Buru Racket-tail parrot. The island's mountainous terrain is interspersed with significant water bodies like the Apo River and Lake Rana, both of which play crucial roles in the local ecosystem.
Characterized by a tropical wet climate, the area experiences high humidity and substantial rainfall, fostering a diverse plant community dominated by hardwood dipterocarp trees. These trees exhibit fascinating reproductive traits, such as masting, allowing for synchronized flowering and seed production. The rainforest is also home to a rich array of wildlife, with numerous endemic bird and bat species, some of which are threatened due to habitat loss.
While conservation efforts are supported by protected areas like Gunung Kapalat Mada and the Masbait Wildlife Reserve, human activities such as logging and agriculture pose significant risks to the rainforest's health. The ongoing challenges from climate change and habitat fragmentation further underscore the importance of preserving this unique ecosystem. Overall, the Buru rainforest represents a vital ecological area that is both diverse and under threat, making it a key focus for conservationists and researchers alike.
Buru rainforest
- Category: Forest Biomes.
- Geographic Location: Southeast Asia.
- Summary: An island tropical rainforest home to unique Asian and Australian fauna, the Buru appears to face low levels of conservation threats.
North of Indonesia's Banda Sea and south of the Seram Sea lies Buru Island, a mountainous oval-shaped formation with an area of roughly 3,670 square miles (9,500 square kilometers). The Buru Rainforest, designated part of the Wallacean biogeographic zone, is home to a unique mix of Asian and Australian fauna. The relative isolation of the island, as well as the presence of two large protected areas, lends a stable outlook to its conservation prospects.
The two most significant bodies of water within the island are the Apo River and Lake Rana. Apo, which at 50 miles (80 kilometers) is Buru's longest river, winds northeast toward Kayeli Bay. Rana is a freshwater lake located almost dead center of the island at an elevation of 2,516 feet (767 meters). The island is mostly mountainous terrain, with the highest elevation being 7,969 feet (2,430 meters) at the top of Mount Kapalamadan. Flat areas, where the island's inhabitants are concentrated, exist mostly on the coast and in the valley around the Apo River.
Buru Island falls under a tropical wet climate regime, influenced largely by equatorial monsoons that bring the most rain from October to April. Due to the irregular terrain, precipitation amounts and patterns vary from the coast to higher elevations. In general, rain falls more than 90 days per year, totaling 60–100 inches (152–254 centimeters), while temperatures average about 80 degrees F (about 27 degrees C). These conditions result in very high humidity (70–90 percent), particularly within the rainforest.
Canopy of Dipterocarps
The Buru Rainforest is dominated by lowland evergreen and semi-evergreen trees, most of which are hardwood tropical trees in the dipterocarp family. Dipterocarps, which make up the emergent and canopy layers of the rainforest, have smooth, straight trunks that rise hundreds of feet toward the top of the forest and sunlight. Branches bearing small leaves suited to abundant sunshine appear only near the canopy, while broad trunk buttresses help to stabilize the tree in the shallow soil. Grooves and drip spouts at the leaf tips help keep the leaves dry and prevent mold growth in the constant rain and humidity.
A peculiar characteristic of dipterocarps is masting, a reproductive adaptation that involves simultaneous flowering of almost all the trees once every two to seven years. This phenomenon is believed to be triggered by patterns in temperature and relative drought. The result is a mass production of fruits and seeds that fall to the ground, ensuring a good supply of seedlings for species propagation. These seedlings can survive for many years in the deep shade of the forest floor, and possess a capacity for rapid growth once a gap in the canopy opens. Common genera of dipterocarps in the Buru Rainforest include Anisoptera, Hopea, Shorea, and Vatica.
Thick lianas, bromeliads, orchids, and other epiphytes complete the canopy layer. These plants grow on the branches of larger trees to get sunlight and water; they draw nutrients from the air and their host plants. Specialized leaves, like those found in pitcher plants, allow these varieties to take advantage of the humid conditions in the canopy to capture and keep abundant moisture.
Small-Sized Fauna
The majority of Buru's smaller animals, such as birds, tree frogs, bats, and snakes, live in this food-rich layer and never venture into the lower strata of the rainforest. Common adaptations include bright colors in distinctive patterns, loud vocalizations, and fruit-heavy diets.
Out of the 178 bird species that have been identified in Buru, 29 are endemic (found uniquely in a biome) or near-endemic to the area. Among these, six species are considered endangered or vulnerable: black-lored parrot (Tanygnathus gramineus), Moluccan scrubfowl (Megapodius wallacei), blue-fronted lorikeet (Charmosyna toxopei), Buru cuckoo-shrike (Coracina fortis), streaky-breasted jungle-flycatcher (Rhinomyias addita), and rufous-throated white-eye (Madanga ruficollis).
Three endemic bat species exist on the island: the Moluccan flying fox (Pteropus chrysoproctus), the Ceram fruit bat (Pteropus ocularis), and the lesser tube-nosed bat (Nyctimene minutus). The latter two species are listed as threatened or vulnerable.
Beneath the canopy is the understory or lower canopy, a shady, cool environment with little air movement and high humidity. Plants in this layer include saplings, large-leaved shrubs, mosses, ferns, and epiphytes that thrive in low sunlight.
The lowermost rainforest strata is the forest floor, a completely shaded environment that is home to termites, fungi, worms, ant colonies, and other small animals that thrive on decomposing organic matter. Despite the large amounts of leaf litter that fall to the ground, and the constant activities of the decomposers, the soil in the rainforest is very low in nutrients and poor in quality. Any nutrients that are released are immediately absorbed by the roots of surrounding trees.
The cool, damp forest floor is where the largest animals are found. One of the four mammals so far identified to be endemic to Buru Island is the wild pig Buru babirusa (Babyrousa babyrussa), which the island's residents hunt for its meat.
Human Activity
Agriculture, logging, and residential activities have cleared away the old-growth forests in the coastal plains and northern parts of the island. However, the presence of many endemic species in the Buru Rainforest biome has afforded interest from scientists and conservationists alike. Two protected zones in the north, Gunung Kapalat Mada and Waeapo, contain 550 square miles (1,424 square kilometers) of stable rainforests and offer a refuge for Buru's plants and animals—both those already discovered, and others believed yet to be identified. In the southern range of the forest is the protected Masbait Wildlife Reserve, which contains forty square miles. In addition, the relative isolation of the island contributes to a positive overall outlook for the preservation of this unique environmental treasure.
Still, human threats loom. Industrial-scale logging has been a factor, as has forest-clearing for agricultural uses near the settled areas. Both activities carry habitat-fragmentation risks. Roads into the forest for logging purposes contributed to soil erosion and landslides. Global warming is projected to increase precipitation across much of the Indonesian archipelago; the impact could increase soil erosion and nutrient runoff on Buru when combined with logging and agricultural clearing.
Bibliography
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Poulsen, Michael, and Frank Lambert. “Altitudinal Distribution and Habitat Preferences of Forest Birds on Halmahera and Buru, Indonesia: Implications for Conservation of Moluccan Avifaunas.” Ibis, vol. 142, no. 4, 2000.
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