Executive summary
Key results
Possum numbers were maintained at very low levels in the treatment area for the sixth year in a row, with no browse observed on the sensitive plant species monitored. Wax chew sticks for result monitoring show a reasonable correlation with residual trap catch indices. Pressure on surrounding populations has been applied via Animal Health Board operations.
Possum control – vegetation response
Possum numbers were maintained at very low levels in the treatment area for the seventh year in a row with no browse observed on the sensitive plant species monitored. Pressure on surrounding populations has been applied via Animal Health Board operations. Control methods moved away from the use of toxins to simply using kill traps. A new line was established on the middle of the road (MOR) ridge and the majority of others were placed along existing Fenn™ trap lines.
Rodent control
Rat tracking indices are indicating that the current trapping techniques are not as effective as brodifacoum when attempting to meet a 5% tracking target. There was however a significant difference between the treatment and non-treatment area. If the target is to be met it is clear that an enhanced trapping effort will need to be developed.
Mustelid control
A moderate mustelid year was experienced based upon capture records. Tracking tunnel data this year demonstrated a significant difference in presence between the non-treatment site and the treated site. A new tracking tunnel site with 13 lines in the Wairau Valley was set up to monitor the Friends of Rotoiti trapping. Ranger trainees from Nelson Marlborough Institute Technology (NMIT) assisted with the establishment and running of these lines.
Wasp control – invertebrate response
The current control area of 1,100 hectares was treated with a non-preferred toxin, Finitron as opposed to the toxin of choice which had been Fipronil. Finitron takes far longer to control wasp numbers however they were reduced below the ecological damage threshold. Inclement weather in February reduced wasp numbers across the treatment and non-treatment areas, although active nest numbers at Rotoiti were declining prior to the wet weather arriving. The response of native invertebrates is still difficult to determine.
Response of native fauna
This was the first year that kaka have bred since the extensive stoat control regime was fully established. There were twelve nests altogether. Nine of these nests were within or on the periphery of the treated area and six were successful, fledging 17 chicks. Six of these chicks were female. These six were fitted with transmitters and five survived to at least two months, a higher percentage than in previous years. Of the nine females with failing transmitters at the start of the season, eight were recaptured and had new transmitters fitted. The number of robin territories held in the survey area has remained stable over the past two years. However, there seems to have been a total lack of recruitment between the two seasons, with no new birds taking up territories in areas of historical robin breeding activity. Five-minute bird counts were characterised by high counts for several species in May.
Reintroductions
After considerable planning and consultation, ten great spotted kiwi were transferred to the RNRP in May 2004. One was injured during the transfer and was sent to Massey for rehabilitation. All nine remaining birds were closely monitored and have remained within the stoat treatment area on the eastern side of Lake Rotoiti.
Advocacy and education
New interpretive panels with a significant RNRP component have been commissioned to be erected at the lookout beyond the Mt. Robert car park. Talks and or/tutorial walks were given to schools and several tertiary classes almost every week of the school year. The introduction of great-spotted kiwi involved considerable advocacy through the media releases, radio interviews and an event to welcome the first birds. Additional advocacy was promulgated around the threat of dogs to kiwi.
Volunteers and Friends of Rotoiti
An enormous amount of work was carried out by volunteers this year totalling 347 days. Volunteers comprised 18 individuals, Friends of Rotoiti, two local Conservation Corps groups and the Nelson Marlborough Institute of Technology Trainee Rangers class. The Friends now have over 70 members including groups such as 50+ tramping club and Forest and Bird making up a ‘member’ each. The Friends were also involved in the kiwi release.
Skill sharing
Numerous requests for information and advice were received from internal and external sources across a variety of pest control and monitoring programmes. One staff member attended the Mainland Island Hui at Lewis Pass where valuable information transfer occurred. Members of the project team were also invited to be involved in national projects and events such as the D’Urville Island stoat workshop and the International Wildlife Management Congress.
Research
Rotoiti Nature Recovery Project scholarships were awarded to two Canterbury University students carrying out bellbird and beech scale insect research within the project area. Other students from Victoria, Canterbury, Waikato and Otago also took advantage of the area throughout the year. Landcare continued their wasp research and brodifacoum research involvement. Stoat carcasses were sent to Science and Research as part of their national diet analysis.
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