Tropical rainforests are found near the equator where hot, moist air rises and dumps rainfall. They cover about 6% of the Earth's surface, mostly in South America and Brazil. Rainforests have high rainfall, temperature, and humidity year-round and exhibit extremely high biodiversity, containing 40-75% of the world's species. However, tropical rainforests are one of the most threatened ecosystems due to large-scale habitat destruction from human activities like logging and agriculture.

1. TROPICAL
RAINFOREST
SUNITA MATANGULU
M.SC FIRST SEM, 2020

2. DISTRIBUTION
• Found near equator, where hot, moisture laden air rises
and dumps it’s moisture.
• Occurs in Central and South America, central and
Western Africa, South West Asia, northwest Australia, etc.
• Covers about 6% of earth’s surface and are found all over
the world but mostly in south America and Brazil.

4. CLIMATE
•Rainfall: 200-225 cm throughout the year
•Temperature and humidity are high and
constant.
•Variation of temperature between winter and
summer is less.

6. BIODIVERSITY
• Exhibits high levels of biodiversity
• Around 40% to 75% of all biotic species are indigenous to
the rainforest
• Flora is highly diversified, 2.5 km2 may contain 300
different tree species.
• Home to half of all living animal and plant species of the
planet.

7. SOIL CONDITION
• Soil is red latosols and may be exceedingly thick.
• Decomposition is rapid due to warm, moist
condition and abundant decomposers
• Soil is subjected to heavy leaching and tend to be
acidic and nutrient poor
• Most of the nutrients is stored in the biomass

8. FOREST STRUCTURE
• Highly stratified
• Trees generally form 3 layers:
1. Scattered very tall emergent trees with buttressed bases
2. Continuous canopy of 25-35 m tall
3. An understory stratum
• Shrubs and herbs often contain ferns and palms
• Epiphytic orchids, bromeliads as well as vines
• Nearly all plants are evergreen, leaves with moderate size, leathery and dark
green in colour

10. EPIPHYTES ORCHIDS

11. BROMELIADS

12. VINES (LIANAS)

13. EMERGENT LAYER
• Contains small number of very large trees called emergents which grow above
canopy reaching 45-55 m tall.
• Emergents include:
Hymenolobium mesoamericanum
Balizia elegans
Dipteryx panamensis
Heironyma alchorneoides
Lecythis ampla
Terminalia oblonga

14. Hymenolobium mesoamericanum
Balizia elegans

15. Dipteryx panamensis

16. Heironyma alchorneoides

17. Lecythis ampla

18. Terminalia oblonga

19. CANOPY LAYER
• The canopy is the primary layer of the forest forming a roof over the
two remaining layers.
• It contains the majority of the largest trees, typically 30-45 m in
height
• Tall, broad leaved evergreen trees are the dominant plants.
• The densest areas of biodiversity are found in the forest canopy, as
if often supports a rich flora of epiphytes, including orchids,
bromeliads, mosses and lichens.

20. UNDERSTORY LAYER
• Lies between the canopy and the forest floor.
• Is the home to a number of birds, small mammals, insects, reptiles and predators.
• Examples :
Leopard (Panthera pardus), poison dart frogs (Dendrobates sp.), ring-tailed cat
(Nasua nasua), Boa constrictor, and many species of Coleoptera.
The vegetation at this layer generally consists of shade tolerant shrubs, herbs,
small trees and large woody vines which climb into the trees to capture sunlight.

21. LEOPARD POISON DART FROG
RING-TAILED CAT

22. FOREST FLOOR
• The forest floor, the bottom most layer receives only 2% of the sunlight. Only plants
adapted to low light can grow in this region.
• Away from riverbanks, swamps and clearings, where dense undergrowth is found,
the forest floor is relatively clear of vegetation because of low sunlight penetration.
• This more open quality permits the easy movement of larger animals such as:
Ungulates like okapi, tapir
Sumatran rhinoceros, gorillas, many species of reptiles, amphibians and insects

23. OKAPI TAPIR
SUMATRAN RHINO

24. • Invertebrate density and abundance are very high
• Common invertebrate : Snail, Worms, Millipedes, Centipedes,
Leeches, Spiders, etc.
• Common vertebrates : Rhacophorus, Aquatic Reptiles,
Chameleons, many species of Snakes, Birds, Bigger Mammals,
Flying Squirrels.
• Common vegetation : Epiphytes, Bromeliads, Orchids, Rattan Palm,
Amazon water lily (Victoria amazonica), rubber tree (Hevea
brasilensis), bougainvillea, bucket orchid, walking palm, Indian
timber bamboo, silky oak, Corpse flower, pitcher plants, heliconia ,
etc.

25. RHACOPHORUS
CHAMELEONS
FLYING SQUIRRELS

26. RATTAN PALM BROMELIADS
ORCHIDS

27. AMAZON WATER LILY WALKING PALM
RUBBER TREE

28. INDIAN TIMBER BAMBOO
BOUGAINVILLEA
BUCKET ORCHID

29. SILKY OAK CORPSE FLOWER HELICONIA
PITCHER PLANT

30. THREATS
• Most threatened ecosystems due to large scale
fragmentation as a result of human activity.
• Fast human driven habitat destruction is major cause of
species extinction.
• Subjected to heavy logging and agricultural area covered
by rainforests around the world is rapidly shrinking.

31. FRAGMENTATION HABITAT DESTRUCTION