The type of sediment on the bottom of streams affects the types of small creatures living there. Researchers studied different types of streambeds in China and found that the community of these small creatures varied depending on the sediment type, but not so much on the climate or location. They discovered that more diverse communities of these creatures were found on gravel with water plants, while sandy and unstable beds had fewer creatures. Most of these creatures were water insects, with different types dominating on different types of sediment. The diversity of these creatures increased with a specific index related to the sediment type.