Some common benthic macroinvertebrates, or BMIs, include dragonflies, mayflies, and stoneflies (pictured above). These BMIs spend the early portion of their lives in the water, then emerge into their adult form. BMIs are known as bioindicators, and their presence or absence can tell a story about the health of a creek. Sensitive BMIs require clean, oxygenated water to survive. Hence, a change in sensitive BMI populations, like caddisfly or stonefly populations, may indicate a change in water quality.