Here's why:
* Harsh Conditions: The tundra is characterized by extremely cold temperatures, permafrost (permanently frozen ground), and low precipitation. These harsh conditions make it difficult for larger plants to survive.
* Slow Growth: Lichens and mosses are slow-growing, but they are well-adapted to the cold and can tolerate the nutrient-poor soil. They are also able to survive in the short growing season of the tundra.
* Pioneer Species: Lichens and mosses are often considered "pioneer species" because they can colonize bare rock and soil, paving the way for other plants to grow over time.
While other biomes might have some lichens and mosses, the tundra is the only biome where they are the dominant plant life.
