The biome described, with grass-covered land, few trees, and common grazers like gazelles, is likely the savanna biome.
There are several reasons for the low population of trees in savannas:
Climate: Savannas are typically found in regions with a distinct wet and dry season. The availability of water is limited during the dry season, making it difficult for trees to survive. Trees require a consistent water supply to grow and thrive.
Fire: Frequent fires are a natural part of savanna ecosystems. The grasses in savannas can easily catch fire, and these fires help maintain the open landscape by preventing the growth of young trees. Many tree species in savannas have adaptations that allow them to survive and even benefit from fires, such as thick bark that protects them from the flames.
Herbivores: Grazing animals like gazelles play a crucial role in shaping the savanna ecosystem. They feed on grasses and young tree seedlings, preventing trees from establishing and growing. This continuous grazing pressure inhibits the growth of trees and maintains the dominance of grasses.
Soil: The soil in savannas is often nutrient-poor and not as conducive to tree growth compared to other biomes. This limitation on nutrients can hinder the establishment and growth of trees.
Competition: Grasses in savannas are highly competitive for resources like sunlight, water, and nutrients. They tend to outcompete tree seedlings, making it challenging for trees to establish and grow to maturity.
Drought Adaptations: Many plants in savannas have evolved to be drought-resistant. Grasses are better suited to surviving extended periods of drought compared to most tree species.
Selective Pressures: Over time, the natural selection process in savannas has favored the dominance of grasses and the adaptation of animals to this open landscape. This has led to the evolution of animals that are well-suited to grazing and browsing, rather than those that rely on trees for shelter and food.
The low population of trees in the savanna biome is primarily due to the combination of factors such as climate, fire, grazing, nutrient-poor soil, competition, and the evolutionary adaptations of both plants and animals in response to these conditions.