2021 SERN Spring Field Day

6 November 2021

The SERN Spring Field Trip headed to the lower Waiau valley where we heard from Mark Sutton of the Waiau Habitat Enhancement Trust about the created wetlands they developed with the purpose of increasing whitebait and eel populations. SERN visited these wetlands in 2008, not long after the start of their creation, however the area of open water has increased fourfold now. From a lookout on Fishing Camp Rd, looking down over the valley there is a mix of wetlands and pasture area. Mark explained that the restoration project will be self sustaining, with income from baleage covering any costs required to maintain the area. With a good road through the wetlands, we were able to drive through the lower area with several stops to look at the ponds and also plantings that had been undertaken. Flax is the main species planted and is done taking large plants from nearby farms, extracting and planting with a digger, so low maintenance. We also looked at a couple of areas where they had done direct drilling of native seeds, in conjunction with DOC. Grass is the main competitor and spraying plots had been tried. They had also experimented with just clearing the area back to dirt with a digger, but still had to spray regrowth. There were several plots of cabbage trees, one which had been smaller plants and required several years of intensive maintenance to get them going. The second plot larger trees had been put in at a higher cost initially, however little maintenance required and so was seen as more effective. The two inlet streams from the Waiau River now maintain good water levels year round, although some of the ponds do dry out through the summer. This provides good areas for wading birds and two bittern had been seen in the area over the last year. Besides providing excellent habitat for eels and whitebait, the main purpose of the wetlands construction, there is also an abundance of waterfowl and other birds in the area.

In the afternoon we visited Broadlands Bush, owned by the Day family. A 12ha podocarp forest remnant on the banks of the Waiau River, protected by a QEII National Trust Open Space Covenant, there are some magnificent 1000 year old totara within, which we walked down to see, accompanied by Warrick Day and his son, Lije. The last stop was Wairaki Oxbow Lagoon, owned by the Smith family. This wetland area still retains its natural character with flax and carex around the edge, while on the escarpment there are remnants of totara. The Waiau Trust is assisting with fencing of the area and some revegetation work. The Smith family are happy for the public to access the wetland and so the Waiau Trust is also helping with the development of tracks to enable this.

Thanks go to the Biodiversity Team, Environment Southland for their support of this field day in covering the bus cost.