Stream ecosystem health

The mission What we've learned so far What's next How will this help farmers How are farmers involved Additional resources

Indicators of aquatic life are new measurements within the national policy for freshwater management. The research aims to improve the way farmers and the sector assess and report ecosystem health in pastoral streams. It also aims to highlight the positive effects of on-farm riparian planting on stream ecosystem health.

The mission

The aim is to develop better measures of stream ecological health that reflect community and farmer values around freshwater.

What we’ve learned so far

This project is relatively new, but farmers and catchment groups can now use state-of-the-art monitoring that detects fish, insects, microbes, aquatic plants, terrestrial plants and even birds from their genetic material being present in stream water. This genetic material (unique to each organism) is called environmental DNA (or eDNA for short). This method is useful to provide an overall measure of stream condition or ‘ecosystem health’.

Farmers in the Tararua catchment have found information from eDNA more informative than conventional water quality monitoring results.

All living things in or near streams can add traces of genetic material to the water (scientists call this genetic material environmental DNA or eDNA).

The sampled eDNA gives scientists a snapshot of the health of the waterway and its species.

Sampled eDNA

What's next

By mid-2023 DairyNZ will have a report completed presenting evidence that riparian planting and restoration is one of the most effective on-farm actions to help improve stream habitat and ecosystem health in agricultural catchments.

How will this help farmers

Farmers are stewards of the land and want to see healthy local streams. This project will provide farmers with a low cost, scientifically robust method to assess and monitor ecosystem health in their local streams and rivers. This project will provide a strong evidence base to inform council limit setting processes by providing robust information on the factors contributing to ecosystem health. It will also show how riparian planting and restoration can significantly improve stream health.

Tararua farmers being shown how to deploy eDNA sampler

How are farmers involved

Currently, DairyNZ has farmers monitoring stream ecosystem health using eDNA in Manawatu-Whanganui, and the Pokaiwhenua catchment (Waikato).

Dr Craig Depree, Principal Scientist

Craig Depree came to DairyNZ four years ago, after spending 18 years as a water quality scientist at NIWA. He leads DairyNZ’s freshwater programme, and the preparation of scientific evidence for regulatory processes.

Last updated: Feb 2024
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