1.3.3. Understory layer

The understory layer encompasses usually small trees, shrubs, ferns, and native bananas, which may attain 3.66 m height. Mosses, fungi, and algae often grow on the trees. This layer is rich in insects, such as bees, stick insects, ants, beetles, and butterflies, which serve as sources of food for a wide array of birds and reptiles. The fauna species encompass bats, monkeys, snakes, lizards, jaguars, frogs, and invertebrates.

#### 1.3.4. Forest floor

This is the bottom layer of tropical rainforest. This layer is dark due to dense ground vegetation and only 2% of sunlight reaches the floor. Due to less availability of sunlight, only few plant species can grow. This layer is rich in organic matter such as fallen leaves, seeds, fruits, and branches. Furthermore, this layer is rich in fungi and mosses. The fauna species of the forest floor include elephants, tigers, pumas, leopards, jaguars, ocelots, mongoose, tapirs, cassowaries, okapis, armadillos, pigs, and gorillas.

#### 1.4. Environmental services provided by fauna in tropical rainforest

Faunas are the important component of the tropical rainforest ecosystem and provide a wide array of environmental services such as; they keep tropical rainforest systems in balance through pollinating a variety of plant species, dispersing seeds, controlling pest population and reducing the damage caused by different pest species, scavenging carcasses, and recycling nutrients back into the soil.
