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Upper Hutt Leader : June 1st 2011
47 UPPER HUTT LEADER, JUNE 1, 2011 To order your own copy of photos in this paper, or other CCN titles, check out: pix.ccn.co.nz Noisy traps trialled on possums Danger: A new type of possum lure uses bioacoustics to attract the furry creatures of the forest. By PIERS FULLER If a box makes a noise in the for- est, will a possum care? This is a question that PhD student Matt Kavermann is exploring as he develops a novel approach to attracting possums and other pests. If you had been driving quietly up State Highway 2 towards Mount Bruce recently you may have heard some strange noises coming from the Montfort Trimble Forest at Mikimiki. The noises were part of a research experiment being carried out by the former Wairarapa student. Mr Kavermann is now a PhD candidate in the newly established Centre for Wildlife Management and Conservation at Lincoln Uni- versity and he is studying the use of bioacoustics (sounds attractive to pest animals) for improving ver- tebrate pest control in New Zea- land. For his experiments Mr Kaver- mann is using beeps, begging calls of native birds, distress calls from other prey species such as rabbits and the mating calls from targeted pest species to attract pest animals to specially designed camera traps that photograph any passing animals. The preliminary work in Trimble Forests is using repeated beeps (much like a truck backing) in an attempt to attract any possums in the area, as similar sounds have shown promise of attracting possums in earlier pen trials. The trials have just finished and the preliminary results look positive. Mr Kavermann is also involved in other research investigating the wave of new self-setting bait stations that are being designed to be left unattended in the field for extended periods of time. It is believed that combining an audio lure (which can remain attractive longer than conven- tional lures) with the new bait- station technology will help to cre- ate long-term, cost-efficient pest control strategies in the future. They are keen to experiment with different sounds to see what effect they would have. We could play Mozart or what- ever is attractive to possums, says Mr Kavermann. If we could find something that could project further into the for- est or was more attractive to possums, we would use that. The devices use common waveform audio files (WAV) for the audio and these can easily be swapped using a memory card. For now Mr Kavermann will continue to work with the Montfort Trimble Foundation, along with the Department of Conservation and other private land owners while he collects the data he needs for his studies. He is heading to Coromandel soon to carry on with more trials. He says the flexibility and affordability of technology makes this type of experimentation much easier. This technology has allowed for this research to begin in earnest now. All bets off for road tunnels By REBECCA THOMSON Big quake spells disaster Wellington s oldest tunnel will not be safe in a major earthquake. Wellington City Council has admitted it is unlikely the Karori tunnel entrances would withstand an earthquake greater than mag- nitude 7. However, strengthening work is to begin later this year. The Karori tunnel, which opened in 1900, has cracks and leaks, and the hillside above the Kelburn entrance is unstable. Transport assets manager Deven Singh said independent structural engineers had assessed the tunnel. The portals [entrances] could well fall in in a major quake, but they are perfectly fine in normal situations, Mr Singh said. The barrel itself should with- stand a [magnitude] 6 or 7 earth- quake, but if there s a really sig- nificant event, like an 8, then all bets are off. Of course, it depends where the earthquake is and how deep it is. The Wellington fault runs under the Karori tunnel and an earthquake along that fault could result in damage to the hillside and tunnel entrances. Mr Singh said the Karori tunnel could be closed for up to three months if the portals collapsed. However, the council s plans to strengthen it include bracing the portals with metal rods, fixing the cracks and leaks, and building a retaining wall along the hillside near the Kelburn entrance. GNS spokesman John Callen said tunnels generally performed well in earthquakes, although the portals could suffer damage. Our view is that the Karori and Northland tunnels would probably survive all but the biggest quakes reasonably well. Mr Singh said work on the tun- nel would start after the Rugby World Cup, once engineers had determined how to do so without causing too much disruption to traffic. Council engineers have also assessed the Seatoun tunnel and Hataitai bus tunnel, and the portals of both are considered an earthquake hazard. It has been recommended they be braced with steel plates and bolts. Work on the Hataitai tunnel is scheduled for 2013-14 and on the Seatoun tunnel for 2016-17. The Northland tunnel portals also needed strengthening, Mr Singh said. Northland tunnel will be reassessed during the 2011-12 financial year and strengthening work is scheduled for 2014-15. The Terrace and Mt Victoria tunnels are the responsibility of NZ Transport Agency. NZTA spokesman Anthony Frith said both tunnels were seis- mically sound, but were undergoing maintenance work. Both tunnels fire-fighting, ven- tilation and drainage systems are being upgraded. Work on the 80-year-old Mt Vic- toria tunnel is being carried out in two stages. The first stage began last week and is expected to cost $17.5 million. The second stage is expected to be completed next year. The cost of that has not been finalised. The $50m Terrace Tunnel refurbishment is expected to be completed in September. Work on the three-lane, 446-metre-long tunnel began in December.
May 25th 2011
June 8th 2011