Prelims 2021

Q. 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
3.Grazing herbivores
4.Seasonal rainfall
5.Soil properties
Select the correct answer using the code given below.
a) 1 and 2
b) 4 and 5
c) 2, 3 and 4
d) 1, 3 and 5
Correct Answer: c) 2, 3 and 4

Question from UPSC Prelims 2021 GS Paper

Explanation : 

Factors Influencing Savanna Ecosystems

Savannas are dynamic ecosystems influenced by a variety of factors that prevent the establishment of dense forests. Among these, fire, grazing herbivores, and seasonal rainfall play pivotal roles in maintaining the characteristic grasslands with scattered trees.

Fire’s Role in Savannas

Both natural and man-made fires are a common sight in savanna ecosystems. These fires are crucial in preventing tree saplings from growing into a closed canopy, especially during the dry season when the grass is most flammable. This process is essential in maintaining the savanna’s grassland areas.

Grazing Herbivores and Their Impact

The presence of large herbivores, such as zebras, elephants, and wildebeests, is another significant factor. These animals not only graze on the grasses but also trample over saplings, inhibiting their growth into mature trees and thus preserving the savanna landscape.

Seasonal Rainfall Patterns

Distinct patterns of wet and dry seasons define savannas. These rainfall patterns dictate the survival of vegetation, with trees often being limited to areas that can sustain them with sufficient water. The prolonged dry seasons favor grasses that are well-adapted to these conditions over trees.

While burrowing animals and termites, as well as soil properties, do affect the savanna ecosystem, they are not the main factors that control forest development. These elements influence soil structure and plant growth but do not have a large-scale impact on tree establishment like the aforementioned factors do.

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