Geoscience Reference
In-Depth Information
Madagascar
Madagascar has a small rainforest, but one quite high in biodiversity. Located
along the east coast of the island country at elevations between 0 and 2,600 ft (0
and 800 m), the forest experiences warm temperatures, high humidity, and more
than 80 in (2,000 mm) of rainfall annually.
Like other rainforests, five forest layers appear in the forests of Madagascar.
The canopy is rather low (80-100 ft [25-30 m]), with high tree density and a mix of
tree species. Unlike Africa, no single tree dominates the canopy. The trees are typi-
cally straight, their branches covered with lianas and epiphytes. The canopy is not
strictly closed; most trees have spaces between their crowns. Canopy-dwelling ani-
mals must be able to negotiate these gaps by climbing, leaping, gliding, or flying.
Dominant trees are members of the legume (Fabaceae), mangosteen (Clusia-
ceae), ebony (Ebenaceae), palm (Arecaceae), euphorb (Euphorbiacea), sapodilla
(Sapotaceae), frankincense (Bursiaceae), and elaeocarpus (Elaeocarpaceae) fami-
lies. Elaeocarps occur in Madagascar and throughout Asia, but not in Africa. More
than 170 palms are present, many related to Asian palms. Pandans (Pandanaceae)
and bamboos (Poaceae) are abundant. More than 90 percent of the trees and shrubs
in the rainforest are endemic.
Animals of the African Rainforests
The animals of the African rainforest are quite diverse with species found nowhere
else in the world. New species continue to be discovered within the African rainfor-
est. As exploration into less-accessible forested areas continues, a fuller under-
standing of the animal life will emerge. The continuation of taxonomic and
evolutionary analyses of newly discovered animals is also important in this
understanding.
Mammals
More than 270 species of mammals, belonging to 120 genera, and more than 25 dif-
ferent families have been identified in the lowland rainforests of Africa (see Table 3.3).
The African rainforest contains an exceptional diversity and abundance of large
mammals, unmatched by any other tropical rainforest. Questions remain regarding
the geographic origin and evolutionary relationships of some mammals present in the
African rainforest, particularly regarding their relation to South American mammals.
Several reasons exist for the remarkable diversity of animals. Stratified forest
layers result in a multitude of habitats in the canopy and on the ground. Forest
resources are remarkably varied, providing different opportunities for different
mammals. Numerous plants provide leaves, shoots, flowers, fruits, seeds, and bark,
as well as insects for consumption. These resources are abundant and available
throughout the year. Mammal distributions are closely correlated with the different
vegetation layers. The upper canopy houses primates, rodents, bats, pangolins, tree
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