Stream benthic invertebrates are important indicators of aquatic health and have been monitored in PEI National Park to assess community diversity as well as abundance of pollution tolerant and intolerant taxa in streams. Benthic invertebrates are collected on an annual basis using the sampling methods developed by Environment Canada for the "CABIN" stream monitoring network. Samples are sorted and invertebrates are classified to the lowest possible taxomonic classification to determine abundance and biodiversity in these aquatic ecosystems. Community biodiversity is assessed using the Simpson’s reciprocal index (D). The Hilsenhoff Biotic Index (HBI) is also used to assess benthic invertebrate species tolerance levels to organic pollution. Thresholds for community biodiversity metrics were created from existing research on stream benthic community abundance and richness in PEI’s low order streams.