Tropical Savanna

Climate, Soils, Vegetation, Human Impact

Edu Level: Unit2

Date: Aug 8 2025 - 8:40 PM

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Tropical Savanna

5°–23.5° N and S of Equator
Found in Venezuela (Llanos), Guyana (Rupununi), Sub-Saharan Africa, Brazil, Northern Australia
Caribbean examples: Aripo Savannas (Trinidad – edaphic, soil-driven), Cuba

Open grasslands with few scattered trees
Trees widely spaced due to limited water
NPP: ~900 g/m²/year
Tree adaptations:
- Long taproots, waxy small leaves, thick bark, some deciduous
- Pyrophytic (fire-resistant) species, e.g. Baobab
Grasses grow in clumps/tussocks, die back in dry season but regrow in wet

Horizons not well defined
Cracks in dry season, sticky when wet
Clay-rich parent material
Thin humus layer
Hard laterite pan forms from seasonal leaching and capillary action → hinders ploughing and root growth
Iron and aluminium oxides remain in soil → reddish color

Desertification:
- Overgrazing, deforestation, and unsustainable farming lead to land degradation
- Major problem near desert margins in Africa; worsened by climate change
Fires:
- Natural and necessary for ecosystem balance, but uncontrolled fires (from humans or lightning) destroy vegetation and soil quality
Overgrazing & Soil Compaction:
- Excessive livestock trampling compacts soil → poor aeration, reduced grass growth
- Ploughing during dry season breaks soil structure
Squatting & Urban Expansion:
- At Aripo Savannas, illegal settlers destroy native vegetation and erect concrete structures
Conservation Efforts:
- Aripo Savannas Scientific Reserve is legally protected; permits required to enter
- Home to 4 endemic plants and rare insectivorous species
- Used for education, research, and ecotourism
Tourism:
- African savannas attract wildlife-based tourism (e.g., safaris), bringing economic benefits but also risks of habitat disturbance