Geoscience Reference
In-Depth Information
Termites are abundant in seasonal forests. These social insects play a crucial
role in maintaining the ecosystems. Tropical Africa has the richest diversity of ter-
mites in the world, particularly soil-feeding termites. Their ability to feed on dead
plant material makes them vital players in the forest. Termites are estimated to con-
sume up to one-third of the annual litter, by decomposing it completely or making
it more available for other decomposers. Termites are an important food source for
some specialized forest mammals, such as pangolins and aardvarks. Some termites
build large mounds or elaborate arboreal nests, others live entirely underground,
often sharing the nest with pouched rats. Like ants, termites maintain large colo-
nies of a few hundred to several million individuals. Three main groups of termites
inhabit the seasonal forests: damp wood termites, dry wood termites, and the so-
called higher termites (see Chapter 3).
Ants, bees, and wasps are found throughout the seasonal forests of Africa.
Many have well-developed social structures and live in communities. Some feed
on pollen and nectar, while others hunt small animals. Ants can be predators,
decomposers, seed dispersers, and guardians of new growth. They can be found at
all layers of the forest, using many different food resources. Army ants, driver ants,
and weaver ants live within the forest. The African expression of the rainforest in
Chapter 3 provides a detailed description of these types of ants. Other ants have im-
portant mutualistic relationships with trees, particularly acacias. While the ants
protect the tree from herbivores, the tree provides the ants with shelter and food
(see Figure 5.17). Insects such as grasshoppers, crickets, stick and leaf insects, cock-
roaches, mantids, flies, and fleas all play important roles, and each exploits a differ-
ent niche within the forest.
Arachnids are numerous in the rainforest. Burrowing scorpions, crawling scor-
pions, flat scorpions, thick-tailed scorpions, and whip-tailed scorpions are found
within the seasonal forests. Spiders are abundant nocturnal predators. Numerous
other invertebrates play important roles in the maintenance of the tropical seasonal
forests in Africa. Millipedes are scavengers and decomposers of vegetation and ani-
mals. Carnivorous centipedes feed on arthropods, worms, and small vertebrates.
Human Impact on the African Seasonal Forests
Humans have greatly affected the seasonal forests of Africa and caused the loss of
most forests throughout the continent and on Madagascar. Increased populations,
forest settlements, and clearing forests for agricultural and fuelwood are the main
reasons for forest destruction. As population increases, further encroachment into
the forest takes its toll on the plants and animals, making them vulnerable to degra-
dation and loss. Most of the seasonal forests of West Africa have been destroyed
already. What remains are small fragments interspersed amid the vast savannas.
Decreased forested land leads to changes in climate, causing further desertification
at forest margins. With large-scale human movements forced by armed conflict
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