Source: Environment Canterbury Regional Council
The bug bags provide a short-term habitat for macroinvertebrates, bugs, worms, and snails that may have otherwise drifted past.
Dr Issie Barrett from the Waterways Centre and Matt Stanford, Enviroschools Selwyn facilitator, worked with Glentunnel, Hororata, Greendale, Springston, and Leeston Enviroschools to take a baseline water quality assessment at each site using the types of macroinvertebrates they found.
“There are lots of different types of bugs that can live in the river and what we want to see is lots of diversity, because that’s going to be the healthiest river,” said Issie.
She explained that certain bugs were indicators of water quality – for instance, stoneflies are intolerant to pollution, so high numbers of stoneflies indicated better water quality. On the flip side, high numbers of invertebrates like snails and worms would suggest that the waterway might be polluted.
The big question at sites where we don’t currently find the sensitive species is, “are they just drifting past because there is nowhere suitable for them to live?” This is what deploying the bags may tell us.
Ākonga/students report mixed results
In a joint meeting, each school shared the type of bugs that had ended up in their bags and compared that with baseline sampling. The bags deployed near Whitecliffs and Glentunnel were located furthest up the awa and had lots of sensitive species like green stoneflies, dobsonflies and single gill mayflies, which indicated a higher water quality.
Over the years the students in these areas have led restoration efforts along the awa with riparian planting and are proud of their connection to this waterway.
Further downstream, students discovered some pollution-tolerant species like snails, flatworms, segmented worms, and blood worms in their bags.
Issie said that seeing species like worms isn’t necessarily a bad thing. “A fully functioning ecosystem will include both sensitive species and the more tolerant types.”
Spring flood hinders success
Flooding of the Waikirikiri awa in October meant some of the bug bags were swept down the river.
“None of the students’ hard work will go to waste,” said Issie. “Bags that were washed away will likely end up in Te Waihora/Lake Ellesmere and become habitats for invertebrates and small fish.”
“The flood that we had ended up testing the design limits of our bug bags and revealed some deficiencies that the students have already thought of ways to rectify,” explained Matt.
Despite the flood, ākonga still found the creation and launch, as well as the identification of macroinvertebrates, to be an exciting and beneficial activity.
Leeston school said that some of their children didn’t even know there were bugs in the river, so it was an interesting learning experience for them.
“This project wasn’t about having all the answers,” said Matt. “We wanted to foster the children’s curiosity and get them to ask the ‘why’ question. When young people are connected to their local environment, they act instinctively in ways to protect it. I’m sure we will see some cool action from them aimed at improved water quality along the Waikirirkiri awa.”
