In the grasslands, trees do not replace the grasses as a part of an ecological succession because of:
Answer & explanation
Answer: (c) water limits and fire
The answer is (c). Grasslands occur where rainfall is limited and often seasonal, and periodic droughts are common. Fires are also frequent. Under these conditions tree seedlings struggle to establish, while grasses recover quickly because their growing points lie at or near ground level. Succession therefore stops at the grass stage, held there by water limits and fire.
- ✗ (a) Insects and fungi are not what keep trees out of grasslands. The controlling factors are water supply and fire.
- ✗ (b) Sunlight is plentiful in open grassland, so light does not stop trees. Light competition matters under a forest canopy. Lack of nutrients is not the reason either: many grassland soils, such as prairie soils, are deep and fertile.
- ✓ (c) Periodic drought limits the establishment of trees. Recurring fire kills woody seedlings and shrubs, while grasses regrow from ground level. Without fire, shrubs and trees would take over grasslands and convert them to woodland or forest.
- ✗ (d) Option (c) gives a valid cause, so 'None of the above' cannot be right.
Remember · Grasslands are held as a stable community by limited or seasonal water and by recurring fire. Without fire, grasslands would progress to woodland or forest.
Sources
- FAO – Grasslands of Central North America (Chapter 6) ↗ “Sauer (1950), in contrast, argued that grasslands were maintained by periodic fires. Without fires, grasslands would progress to woodlands or forest. … One prominent feature of grasslands is a variable climate, with periodic droughts a common feature”
- U.S. National Park Service – Grassland Fire Ecology Resource Brief ↗ “Without fire, shrubs and trees would take over grasslands, effectively converting them to forest, and non-native vegetation would spread.”
Question: UPSC Civil Services (Preliminary) 2013, General Studies Paper I. Explanation: Minimalist IAS, checked 25 Oct 2026 (how we verify). ·
