Ecological Aspects of Savanna Forest Biomes

Wednesday, July 22, 2020

'Savana Region' has been used by the climatologists as a climatic zone i.e. Tropical wet and dry climate (Aw climate in Koeppen's classification while botanists used it as a type of vegetation community characterized by dominance of grasses.

Savanna  Biome normally refers to vegetation community of the Tropical areas which is characterized by the dominance of ground cover by partially xeromorphic herbaceous plants, upper stratum of scattered trees and middle layer of sparse shrubs. It is found generally from 10 to 20 degree latitude in both hemisphere.
Savanna Biome is mainly found in:- 
1. Lianos (Venezuela and Columbia) 
2. Campos (Brazil) 
3. Savanna (Africa)
4. Guinea
5. Paraguay 
6. Savanna of India 
7. Central America's Mountainous Region
8. Downs (Australia)
Savanna Biome Distribution

Formation of Savanna Biome 

Savanna Biome is formed due to interferences of human as well ass natural disturbances like forest fires, deforestation, overgrazing etc.


Savanna Biomes are characterized by Wet and Dry seasons having Mean high temperature throughout the year and abundant insolation. Temperature never falls below 20 degree Celsius in any month of the year. 
Mean Annual Rainfall ranges between 25 cm to 50 cm on the desert fringes and 130 to 200 cm on its border with Equatorial Climate.
On the basis of combination of temperature and humidity climate of Savanna Biomes are divided into three seasons:-
  1. Cold Dry Season:- Having day temperature between 26 degree Celsius to 32 degree Celsius, while night temperature is 21 degree Celsius.
  2. Warm Dry Season:- Here temperature ranges between 32 degree Celsius to 38 degree Celsius and Sun remains overhead.
  3. Warm Wet Season:- 80% to 90% of the total rainfall in Savanna Biomes is happen in this season.

Vegetation in Savanna Biome

Savanna Biome is divided into three vegetative Zones:-

1. Ground Layer 

This layer is dominated by grass and herbaceous plants. 
Grass are generally thick, stiff and hard. It's height ranges from 80 cm to 305m and of coarse perennial that is seasonal and shed during summer season but regenerate in wet season. 
Important grasses of Savanna are Hyparrhenia (Elephant grass), Cylindrica (found in African Savanna).

2. Middle Layer 

Dominated by herbaceous plants, shrubs and very stunted wooded plants.

3. Top/Canopy layer 

These generally range between 5-6 m. But these trees evolved itself like needle shaped leaves, leaves develop into scales in such a way that, it can reduce the water loss through transpiration.
Some trees shed their leaves during dry period or some have roots going down Earth upto 5-12 metres so as to remain green in summer also 
Example - Eucalyptus, Pine (Hundras), etc. 

Some of the trees of Savanna are fire resistant (Pyrophytic) as they have thick bark and bud scales.

Animal Species in Savanna Biome

Diversity of animal species depends on two factors :- 
  1. Different Savanna Biome is evolved differently. 
  2. Degree of human interference in different seasons.

Mammals of Savanna are:-

I. African Savanna - African Buffalo, Giraffe, elephants, Antelope etc. 
II. Australian Savanna - Marsupials (having pouch in body to feed and keep offspring in it), Kangaroo (1.5 m tall), Wallaby (only 30 cm tall). 
III. South American Savanna - Deer and Guanaco.
Animals of Savanna are basically divided into five types. 

  1.  Animals with little or no migration:- Giraffe, Grant's gazelle, Harte-beest etc.  
  2. Animals having partial Movement (during dying season):- Impala 
  3. Animals having partial movement (during wet season):- Water hog, Dikdik, Water buck, rhino etc. 
  4. Animals migrating in dry season:- Buffalo, Zebra, Wild beast, Elland, Elephant etc. 
  5. Animals used to passage migration:- Buffalo, Zebra, Elephant etc. 

Man and the Savanna Biome 

  1. Frequent forest fires caused by human interference and natural calamities lead to destruction of Savanna Biome 
  2. Explosion in population across the world in 50 years lead to destruction of Savanna Biome (as it is easy to clear it) as the demand of food-grain increased more than three times and green revolution also lead to expansion in cultivation to these areas.
  3. With rise in agriculture, the domestication of animals also risen from 50 years and hence resulted in to over-grazing hence it reduced considerable overtime.