Taking stock of predator control
From rabbit numbers to marine habitat surveys
At the recent meeting of Wellington Regional Council’s environment committee, which I chair, we had updates on environmental operations, so I thought I’d provide you with a bit of a taster of our work.
Recently we have kicked off some publicity for annual rook control, and our signs around the region are generating inquiry, with Wairarapa farmers phoning in to report rook sightings.
Rabbit enquiries remain constant, but we won’t do any more pindone rabbit control until early 2024, as spring grass growth and rabbit breeding cycles mean control operations will limit our effectiveness. From July 2023 to September 2023 we made 1.37 tonnes of pindone carrot bait and distributed it almost entirely in Kā piti, with a few Hutt Valley sites.
Regional Predator Control Programme work has been slowed by sodden ground conditions limiting access to sites.
Possum habitat areas are being targeted with control, directed towards seasonal food sources to avoid wet areas until the land dries out and access is possible again. Existing bait stations that have been in place for a long time are being removed in possum control operations where there are low possum numbers. These are less likely to be utilised on a regular basis, and keeping infrastructure fresh is our preferred approach.
Marine habitat mapping surveys have been ongoing since December last year and the results have been recently reported. Working in partnership with the National Institute of Water and Atmospheric Research (Niwa) and Victoria University of Wellington, we have mapped numerous high-biodiversity habitats in Wellington Harbour, Wellington’s south coast and along the Porirua and Kā piti coastlines.
Surveys revealed rich sponge gardens, meadows of tube worms, horse mussels and brachiopods, all of which in turn provide habitats for a range of other species.
These habitats will be assessed against established criteria and scheduled in the Natural Resources Plan as sites of significance for indigenous biodiversity.
This summer, the Terrestrial Ecology state and trend surveillance programme will complete its second sampling cycle.
While the first cycle gave us a picture of the state of the region, completing subsequent cycles will allow us to track the trend in terrestrial biodiversity across the region.
Vegetation, birds, possum, and ungulate richness and diversity are measured to inform the health and pressures on terrestrial environments. The work underpins our regional policy and has provided deeper insight into the prioritisation
and effectiveness of environmental management interventions.
Mustelid trap servicing to protect river and wetland bird¯species has started for the year in Otaki as part of the Regional Predator Control Programme.
A report on the health of the Waikanae Estuary shows overall the estuary has shown marked variation in sedimentation, sediment mud
content and other indicator values since monitoring began in 2010. Monitoring from last summer showed metals continue to be in very low concentrations, sedimentation rates were low and the mud content of sediments was in the “fair” category. The report indicates strong variability in environmental conditions is an inherent characteristic of the estuary and is
determined mainly by flow conditions in Waikanae River. We will continue to investigate and manage current and future catchment activities that could adversely affect estuary state (eg. harvest of plantation forestry).
Penny Gaylor is the Kā piti representative for the Greater Wellington Regional Council.