Biodiversity is important for ecosystems because it plays a critical role in maintaining the balance of different species within an ecosystem. A diverse ecosystem is more resilient to environmental changes, as different species can adapt to changing conditions. Biodiversity also provides a variety of ecosystem services, such as pollination, nutrient cycling, and pest control, which are essential for the health and functioning of ecosystems. Additionally, diverse ecosystems are more productive and can support a greater variety of plants and animals, making them more sustainable in the long term.