Grassland Biome: Steppe to Prairie Transition

The transition of a grassland biome from steppe to another type is primarily influenced by changes in precipitation levels.

Rainfall's Role in Biome Grading

The steppe biome is characterized by semi-arid conditions, receiving relatively low rainfall, which supports shorter grasses and fewer shrubs.

As rainfall increases beyond the level typical of a steppe, the grassland biome evolves. This increased moisture allows for denser, taller grass growth and supports a richer diversity of plant and animal life characteristic of more mesic (moderately moist) conditions.

Comparing Biome Characteristics

• Steppe: Found in regions with low to moderate rainfall (approx. 250-500 mm per year). Often drier than prairies.
• Prairie: A type of temperate grassland receiving moderate rainfall (approx. 500-900 mm per year), supporting taller grasses and a more diverse ecosystem than steppes.
• Savanna: A tropical or subtropical grassland with scattered trees, characterized by distinct wet and dry seasons and higher overall rainfall than steppes or prairies.
• Tundra: A cold, treeless biome with very low precipitation (often comparable to deserts) and permafrost. Not a direct transition from steppe based on rainfall alone.
• Alpine Tundra: Occurs at high altitudes; its characteristics are defined by cold temperatures and altitude rather than a direct rainfall gradient from steppe.

Therefore, where rainfall is higher, the steppe grassland biome grades into a prairie.