UPSC Prelims 2021 Question:

The vegetation of savannah consists of grassland with scattered small trees, but extensive areas have no trees. The forest development in such areas is generally kept in check by one or more or a combination of some conditions. Which of the following are such conditions?

1. Burrowing animals and termites 
2. Fire 
3. Grazing herbivores 
4. Seasonal rainfall 
5. Soil properties
   
   

Select the correct answer using the code given below.

Explanation: 

• In the general pattern Savannas (Sudan type climate) occupy areas between rainforests and deserts. It can be found in Africa, South America, Australia and parts of Southeast Asia.
  
  
• At some point in the semi-arid tropics, available rainfall no longer supports true forest vegetation, leading to the development of savannas. The rain is concentrated in six or eight months of the year, which is followed by a long period (5 months) of drought. So, natural fires occur during this drought period. Fires, which have both natural and human origin, are frequent and periodic in savannas. The savannas, which result under these climatic conditions, are called “climatic savannas”. So, points 2 and 4 are correct.
  
  
• Another type, known as “derived savanna”, results from the clearing of forested lands for agriculture and from herbivores. For example- Elephants − the grazers both eat and trample tree seedlings, inhibiting the regrowth of the woodland. Some savannas of Africa are “grazing sub climaxes”. So, point 3 is correct.
  
  
• The burrowing animals and soil properties do not have a profound impact on the development of the savanna type ecosystem. So, points 1 and 5 are not correct.
   

Therefore, option (3) is the correct answer.

Subject: Geography | Natural Vegetation & Wildlife