Executive summary
Key results
Possum control – vegetation response
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.
Rodent control
A significant reduction in rat activity was achieved compared to non-treatment areas. Tracking tunnel indices were above target levels each quarter, suggesting further work is needed to determine if trapping can cost-effectively reduce numbers to the same levels achieved previously by poisoning. Both effectively targeting mice and removing the negative influence of mice upon targeted rat control remain areas of concern for this programme.
Mustelid control
This was the first full year of mustelid trapping over the expanded control area of 5000 hectares. A low to moderate mustelid year was experienced based upon capture records. This was also the first year that an independent measure (tracking tunnel index) of stoat activity was available. It showed that stoat activity was significantly lower in the project area due to trapping.
Wasp control – invertebrate response
An expanded area of wasp control (1100ha) was successfully treated. Wasp numbers were reduced below the ecological damage threshold for a limited period of time only; however a population difference between sites was demonstrated over a period of ten weeks. This was the last season that the toxin Fipronil was available to us. The response of native invertebrates is still difficult to determine.
Response of native fauna
Kaka did not breed this year as there was negligible seeding of beech trees. Several kaka transmitters failed before expected impacting on the monitoring of this species.
The number of territories held by robins in the study area was less than in previous years, suggesting rodent control and/or mustelid control was not as effective this year.
Bird counts suggested that the increases in some species seen in the earlier years had tailed off. More data is needed to determine if this might be due to higher rat numbers, reduced mustelid trapping density, populations approaching carrying capacity or other factors.
The first repeat monitoring of the Powelliphanta snail population high up in the core area suggested this was stable or increasing slightly.
Reintroductions
After extensive consultation within and outside the Department it was decided to defer the tieke transfer. Following endorsement in principle from the Kiwi Recovery Group the initial planning towards a great-spotted kiwi transfer was begun.
Advocacy and education
The visitor centre display on the RNRP was completely redesigned and a new pamphlet has been produced. One edition of Revive Rotoiti was printed and distributed to 520 recipients. Talks and or/tutorial walks were given to schools and several tertiary classes almost every week of the school year.
Volunteers and Friends of Rotoiti
An enormous amount of work was carried out by volunteers this year totalling 376 days. They ranged from nine individuals, Friends of Rotoiti, two local Conservation Corps groups and Nelson Marlborough Institute of Technology Trainee Rangers class. The Friends now have over 30 members including groups such as 50+ tramping club and Forest and Bird making up a ‘member’ each.
Skill sharing
Numerous requests for information and advice were received from internal and external sources across a variety of pest control and monitoring programmes. Staff also attended the Mainland Island Hui at Lewis Pass where valuable information transfer occurred. The Project team were also invited to be involved in national projects run by both the Department and Landcare Research and these opportunities were taken up.
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 involvement and stoat carcasses were sent to Science and Research as part of their national diet analysis.
back to top