Aquatic invertebrates are excellent indicators of watershed health because they:

• 1. Live in the water for all or most of their life and often live for more than one year
• 2. Are relatively immobile and subject to greater exposure lengths of local water conditions, as compared to mobile organisms like fish that can escape pollution and habitat stressors and return
• 3. Provide a repeatable way to assess the biological health of an aquatic site which can be used to monitor changes over an extended period
• 4. Differ in their tolerance to amount and types of pollution
• 5. Are important components of a stream′s nutrient and energy system