In an ecosystem, why can only one species fill an ecological niche? (Site 1)

Only one species can fill an ecological niche because each niche is destined exclusively for each species, since its structure, physiology and behavior determine it.

Explanation:

An ecological niche is the way in which each species relates to its environment, to other species and takes advantage of the resources available for its development, being an exclusive and individual characteristic of that species.

The ecological niche is a concept that many consider abstract, since it is unique for a species. Each species has a physical structure, functioning and behavior that differentiates it from the others, which leads it to occupy a certain place within an ecosystem, which would be its ecological niche.

Learn more:

Ecological niche link

answer: grassland biomes are closer to the equator and receive more rain.

grasslands are biomes that are dominated by grasses rather shrubs and trees. savanna are biomes that exhibit grasses, shrubs and small tree as vegetation. grasslands are located near the equator of the earth. these are found in north america. savanna biomes are found in africa, south america, australia and india. grassland exhibit moderate climatic conditions, it receives   amount of rainfall higher than savanna.   therefore, savanna exhibit dry and hot climatic conditions.