Geoscience Reference
In-Depth Information
small leathery leaves. In forests with open canopies, the understory is dense. The
trees are not buttressed and few climbing vines are present. The keranga tends to be
less species rich than the lowland rainforest.
These heath forests are composed of dipterocarps, but the species are different
from those in the rainforest. Many small-leaved plants in the myrtle family are
present, as are casuarinas and conifers. Many of these forests tend to be dominated
by a single or a few species. Kerangas form closed forests with the highest trees
about 98-115 ft (30-35 m) tall. Some kerangas are pole forests, with densely
packed straight thin trees 16-39 ft (5-12 m) tall; others are open woodlands.
Wet Forests.
Mangrove forests are found throughout the Asian-Pacific rainforest
along the coasts. They have a simpler structure, with a single canopy layer with
individual species forming pure stands. Different species are distributed in different
zones depending on water level, salinity, and tidal regime. They typically have no
epiphytes or ferns.
Peat swamp forests are another forest type found in Southeast Asia. Peat forests
grow on layers of slowly decomposing vegetation (peat) 3-65 ft (1-20 m) deep.
Water enters the swamp through rainfall, but drainage is poor. Peat forests develop
in concentric circles from the center (the wettest part) outward. In the center, the
trees are quite small, away from the center trees get taller and eventually become
lowland rainforest containing several dipterocarps wherever drainage is sufficient.
Freshwater swamps occur along rivers and can be temporarily or permanently
covered with water. These swamps contain a mixed forest with several canopy
layers. The tallest trees are less than 160 ft (50 m). Here epiphytes and ferns are
more common.
Wet forests occupy 10-15 percent of the area of most Southeast Asian coun-
tries, but they are rapidly shrinking with drainage of the swamps and with develop-
ment within mangrove forests.
Animals
The incredible diversity of flora within the Asian-Pacific rainforest provides abun-
dant niches for a diversity of animals. Animals are able to exploit different canopy
layers, with few moving between canopy and forest floor. Trees are home for most
birds, as well as monkeys, squirrels, amphibians, reptiles, and myriad invertebrates
in the Asian-Pacific rainforest. Many animals are able to glide through the forest.
The forest floor houses larger herbivores and predators, along with smaller rodents,
ground birds, reptiles, and amphibians. The separate designation of West and East
Malesia is useful in discussing mammals. In the West Malesia subregion, placental
mammals are dominant. Pangolins, monkeys, tapirs, elephants, rodents, otters,
civets, leopards, and tigers among others are present. The area east of Wallace's
Line is home to three species of monotremes and hundreds of marsupial species
