River water quality: Macroinvertebrate community index, trends, 1991 - 2020

Adapted by Ministry for the Environment and Statistics New Zealand to provide for environmental reporting transparency. Dataset used to develop the "River water quality: macroinvertebrate community index" indicator (available at www.stats.govt.nz/indicators/river-water-quality-m...).

Benthic macroinvertebrates are small animals without backbones (for example, insects and worms). They live on and under submerged logs, rocks, and aquatic plants on the beds of rivers and streams during some part of their life cycle. Macroinvertebrates play a central role in stream ecosystems by feeding on periphyton (algae), macrophytes (aquatic plants), dead leaves and wood, or on each other. In turn, they are an important food source for fish and birds.

The macroinvertebrate community index (MCI) is used as an indicator of water quality and overall stream health. It is one of five parameters that provide an overview of New Zealand’s River water quality and how it is changing over time. This data shows

• trends in median MCI scores for the 10-year period from 2011 to 2020, the 20-year period from 2001 to 2020, and the 30-year period from 1991 to 2020.

More information on this dataset and how it relates to our environmental reporting indicators and topics can be found in the attached data quality pdf. Summary report available at environment.govt.nz/publications/environment-aotea....