The four major terrestrial biomes
Desert, forest, grassland and tundra — defined by climate, soil and vegetation.
A biome is a large-scale ecosystem with a characteristic climate and community. You need the climate, soil and vegetation of four biomes.
| Biome | Climate | Soil | Vegetation |
|---|---|---|---|
| Desert | Very dry (low rainfall); large temperature range (hot days, cold nights) | Thin, sandy/stony, low in nutrients and organic matter | Sparse; drought-adapted plants (e.g. cacti, succulents) with deep roots and water storage |
| Forest | Varies by type; generally enough rainfall to support trees (tropical forests = hot and very wet) | Often deep; tropical forest soils can be surprisingly thin and quickly leached once cleared | Dense, layered tree cover with high biodiversity (greatest in tropical rainforest) |
| Grassland | Seasonal rainfall, a dry season; warm | Deep, fertile soils rich in organic matter | Dominated by grasses, few trees; grazing animals |
| Tundra | Very cold, low rainfall; short growing season | Thin, waterlogged in summer; underlain by permafrost (frozen ground) | Low-growing mosses, lichens, small shrubs; no large trees |
Why this matters for management. Each biome supports different species and is vulnerable in different ways — deserts to over-grazing and water extraction, forests to clearance, grasslands to over-grazing and farming, tundra to warming and disturbance. Knowing the biome helps predict the impact of human activity (Topic 4.3) and design conservation.
- Desert: dry, big temperature range; thin poor soil; sparse drought-adapted plants.
- Forest: enough rain for trees; tropical forest = hottest, wettest, most diverse.
- Grassland: seasonal rain; deep fertile soil; grasses and grazers.
- Tundra: very cold, permafrost; low mosses/lichens/shrubs, no large trees.
- Climate + soil + vegetation together define each biome.