Key results
Possum control – vegetation response
The results of the Wax-tag monitoring in 2005-06 showed reduced possum numbers in the RNRP core. Chew stick monitoring in 2006-07 has indicated similar or lower possum activity in the RNRP core as in the 2005-06 year. Outcome monitoring of Raukawa simplex by FBI recorded no possum browse. The current level of control is therefore sufficient to protect the core area.
Rodent control
During 2006-07 RNRP tested a ‘detection and staged response model’ of ship rat control. A failure of the ground-based toxin (1080) operation to meet the initial rat control target resulted in an inability to test the ‘detection and staged response model’. The rat tracking rate of 53% is the highest recorded in the Core since the project began. Tracking rates in the lower core showed limited response to the 1080 operation and the switching off of rat trapping on March 9th 2007. A decision was made to cease rat control for the year and devise a new rodent control plan for the 2007-08 year.
Mustelid control
Tracking results continue to suggest that trapping in the RNRP is having a significant impact on mustelid numbers. There were no mustelid tracks detected within the RNRP Core. Non-treatment mustelid tracks (Lake Rotoroa) peaked at 57% in February 2007, which is the highest recorded tracking rate for mustelids since the start of the project.
Wasp control
An effective wasp control toxin - Fipronil - was expected to become available by 2007; however some of the legal issues were unresolved in early 2007 and Fipronil continued to be unavailable. The unavailability of a suitable toxin has been a disappointment to the project.
Response of native fauna
The RNRP kaka monitoring project is nearly completed, with only two females now carrying transmitters. A report on kaka breeding, survival and recruitment is in progress (Genevieve Taylor in prep.). Robin monitoring showed that the number of robin pairs holding territories within the survey area was higher when the toxin Brodifacoum was used to control rats and declined when trapping was the sole method of rat control. Five-minute bird counts were continued during 2006-07, but results and trends are not analysed annually.
Great spotted kiwi
At the end of the 2006-07 year there were a total of 13 adult kiwi radio-tagged in the recovery area, and another was recaptured and tagged shortly after. Kiwi transferred in 2006 dispersed further in their first year than did kiwi transferred in 2004, but all monitored birds remained within the RNRP project area. Only one pair was known to produce an egg in 2006-07 and this resulted in a new chick that survived. A previously unknown subadult weighing almost 2.5kg – most likely the result of breeding in 2004-05 – was discovered sheltering with a known adult during kiwi transmitter changes in June 2007. The other known chick (discovered in May 2006) survived and weighed more than 1.4kg at the end of the year.
Advocacy and education
Two editions of "Revive Rotoiti" were published during the year. Project information and presentations have been delivered at community meetings and forums; and talks were delivered to 21 different school and community groups. Eight groups were involved in guided walks in the mainland island. Media interest in the great spotted kiwi project has remained strong.
Volunteers and Friends of Rotoiti
Nine individuals contributed 106 volunteer hours. A Royal Society fellow commenced work in the mainland island in January 2007. The friends of Rotoiti contributed 333 volunteer days of work during the 2006-07 period, and participated in two training days.
Research
Student research was conducted on: the role of introduced birds as possible competitors with native birds; the effect of Friends of Rotoiti rodent control on lizard populations; factors influencing the recruitment and establishment of fuchsia; competition between native ants and introduced wasps. Landcare Research also continued their fieldwork investigating the impacts of mice and wasps on soil chemistry and soil microbes and invertebrates in a honeydew beech forest.
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