Characteristics of tropical rainforests

Tropical rainforests have distinct characteristics that support a wide variety of different species. This means that they have a high biodiversity. The biotic or living components of the ecosystem and the abiotic or non-living components of the ecosystem depend on one another - a change in one leads to a change in the other.

Tropical rainforests are mostly found in South America, central Africa, and south Asia.

Climate

  • Very wet with over 2,000 mm of rainfall per year.
  • Very warm with an average daily temperature of 28°C. The temperature never drops below 20°C and rarely exceeds 35°C.
  • The atmosphere is hot and humid.
  • The climate is consistent all year round. There are no seasons.

Soil

  • Most of the soil is not very fertile.
  • A thin layer of fertile soil is found at the surface where the dead leaves decompose.
  • It is red in colour because it is rich in iron.
  • Due to heavy rainfall the nutrients are quickly washed out of the soil.

Plants and animals

  • The warm and very wet climate provides perfect conditions for plant growth.
  • The wide range of plant species supports many different animals, birds and insects.
  • Species have adapted to the conditions of the rainforest, eg trees and plants have shallow-reaching roots to absorb nutrients from the fertile top layer of soil.

Structure of a tropical rainforest

A tropical rainforest is made up of the following layers:

  • Ground level - contains less vegetation due to the dark, damp conditions, a thick layer of decomposing leaves and buttress roots of trees.
  • Shrub layer - dense and dark with small plants.
  • Under canopy - contains younger trees and saplings competing for light in dark conditions.
  • (Main) canopy - the 'roof' of the forest. Contains tall trees, climbing plants like vines and lianas. 50% of rainforest life is found here.
  • Emergent - contains the tallest trees emerging out of canopy.
Emergents at the top receive most light. Beneath is the canopy, then the under canopy, and lastly the shrub level, receiving the least light.