Figure 1: Tracking rates in the East Harbour Northern Forest KNE site Mainland island and Non-treatment area. Note that mast years are determined based on measured hinau (Elaeocarpus dentatus) fruit fall. Toggle through the tabs to see different animals, hover over the charts series to specific results, and click on legend entries to highlight and show/hide series. Use the month checkboxes on the top-right of charts to show/hide data from those monitoring months.
Figure 2: East Harbour Northern Forest KNE site mainland island, showing the locations of the tracking tunnel lines.
Pest animal control regime: Possums are controlled throughout the KNE site using Possum Master and Timms kill-traps spaced at 150 m intervals along main ridges and gullies and by utilising official and unofficial walking tracks. Bait stations containing either bromadiolone or diphacinone are positioned at each trap site to reduce the consumption of trap baits by rodents. The possum traps and associated bait stations are serviced monthly by volunteers.
Rats are controlled within a 400 ha Mainland Island using bait stations, the southern half on a 100 m x 150 m grid and the northern half on a 50 m x 150 m grid. Bait stations are serviced six times a year. Baits (block, pellet or paste) containing diphacinone, bromadioline or brodifacoum are used. Due to the mast fruitfall in 2019, poisoned bait strikers (diphacinone) were deployed in the Mainland Island in October 2019 to bring the rat tracking rate within target levels.
Mustelids are controlled within the Mainland Island using DOC200 kill-traps spaced at roughly 300 m intervals around the boundary of the Mainland Island and on the main internal ridgeline. Volunteers service the traps monthly.
Pest animal control milestones: Possum control was carried out in parts of the KNE site from 1997 to 2001 by contractors and volunteers. Control operations were extended to the whole KNE site in 2001 and 2003-04 using leg-hold and kill traps, encapsulated cyanide and cholecalciferol. Ongoing possum control continued from 2004 using kill-traps.
Bait stations were installed to control rats in an initial Mainland Island area of 300 ha in 2005-2006. Additional lines and bait stations were installed to expand the Mainland Island to 370 ha in 2009 and to 400 ha in 2010. In 2010 bait stations were also intensified in the northern half of the Mainland Island to a 50 m x 150 m grid. The southern half was left at 100 m x150 m spacing. In October 2019 poison bait strikers were deployed in the Mainland Island to counter the increase in the rat tracking rate.
Mustelid traps have been installed within and around the Mainland Island incrementally since 2011.
Surrounding pest control regimes: There is possum and rat control using bait stations filled with brodifacoum adjacent to the northern tip of the KNE site. OSPRI’s TBfree programme undertakes intermittent possum control in the area, the latest of which in May 2017 included the KNE site.
The Educating Residents About Trapping (ERAT) programme run by the Mainland Island Restoration Organization (MIRO) began predator trapping across Eastbourne and the Bays, from Point Howard to Burdans’ Gate, including the foreshore, in 2017. ERAT is deploying a mix of traps (DOC200’s, Victor rat traps in tunnels and Goodnature A24 self-resetting traps) to establish an 80 m x 80 m grid across the suburbs buffering the KNE site.