In an introduction to terrestrial biomes, which terrestrial ecosystem is generally considered the most biodiverse (highest species richness)?

Recognize that tropical rainforests have warm temperatures year-round, high and consistent rainfall, and complex layered vegetation structures, creating numerous niches and supporting a wide variety of species.

Compare this to other biomes: Tundras have cold temperatures and short growing seasons limiting species diversity; temperate grasslands have moderate rainfall but less structural complexity; hot deserts have extreme temperatures and low water availability, limiting species richness.