Tropical rainforest ecosystems

Tropical rainforests are found between the Tropics of Cancer and Capricorn, 23.5° north and south of the equator.

What are rainforests like?

The tropical rainforest contains far more species of plants and animals than any other biome. They cover approximately six per cent of the Earth's surface, and because they get 2,000 mm of rain per year and temperatures range from around 27 to 32°C, conditions are wet and hot all year round so it is a good environment for growth.

Rainforest processes - Costa Rica

Layers of the forest

Diagram of the four layers of the rainforest: forest floor, understory, canopy and emergent layer

Forest floor

  • Very little light reaches the forest floor (2%) - so plants grow slowly.
  • The ground is covered in fallen leaves, rotting branches and twigs and a network of shallow roots.
  • When a tree falls, light is able to get in. This encourages young plants to grow fast. They compete for the extra light and soon fill the gap.

Jaguars, leopards, tigers, elephants and gorillas are found in different rainforests around the world. Lots of insects live here.

Understory

  • Low light conditions (2-15%).
  • Quite open - there is only dense vegetation along rivers and in openings where light gets in.
  • Plants adapted to low light grow here.

Birds, butterflies, frogs, snakes and lots of insects live here.

Canopy

  • The second highest layer - 30-45 metres.
  • The crowns of the trees knit together to form a dense canopy.
  • The canopy blocks out the sun from lower layers and intercepts (catches) rainfall.
  • It contains the most plant species.

Birds, monkeys, frogs, sloths, lizards, snakes and many insects live here. This layer contains the most animal species. Some creatures never go to the forest floor.

The emergent layer

  • The tallest layer - over 40 metres.
  • Contains only a few tall trees which grow taller than the trees of the canopy.
  • The plants are made for living in dry conditions because it’s very sunny.
  • They have small, waxy leaves to prevent them drying out.

Eagles, butterflies, small monkeys and bats all live here.