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Introduction
Any subsequent stock incursions will be quickly dealt with by removing the animals and repairing fencing as required. Annual inspections of all boundary fences will be undertaken to minimise the likelihood of such excursions and those involved in the management of adjacent areas will be informed of the desire to keep Tiromoana Bush free of domestic stock.
The approach to animal pest management recognises that different animal pests pose differing threats to restoration and indigenous biodiversity. A prioritisation system is therefore used for management work based on likely threats of individual pest species. The priority ranking and objectives for control of each pest are regularly reviewed to allow for adaptive pest management.
The overall approach to animal pest control will meet accepted best practice standards (e.g., as defined by ECan or DOC) and the methods used will be kept under regular review through an adaptive management approach. All animal pest control programmes will meet the legislative conditions and requirements set by the relevant Acts and Regulations of Parliament including the Wild Animal Control Act 1977, the Resource Management Act 1991, the Health and Safety in Employment Act 1992, the Biosecurity Act 1993, the Hazardous Substances and New Organisms Act 1996, the Animal Welfare Act 1999, and the Pesticides (Vertebrate Pest Control) Regulations 1983. All pest control operators will be required to have appropriate pesticide licences where required. Details of the methods to be used for animal pest control will be developed with the contractors undertaking the work and will be based on current best practice guidelines.
Introduced pests targeted for control are split into two management groups: High priority (possums, stoats, ferrets, weasels, rats, rabbits, hares, feral deer, feral goats, wasps); Low priority (feral cats, feral dogs, feral pigs, hedgehogs, mice). Some pest species (e.g., possums, cats, rats and mice) can be encouraged into an area by the presence of rubbish, especially organic rubbish. Obviously the presence of a major landfill adjacent to the restoration area acts in this way. However, Transwaste Canterbury Ltd. have a major ongoing animal pest control operation as part of landfill management.
Brushtail possums: Brushtail possums are a direct threat to restoration plantings and general biodiversity values, as well constituting a threat to neighbouring land holders in terms of production (damage to young pine trees and spread of bovine Tb). An ongoing possum control operation for bovine Tb occurs in the Kate Valley arfea including Tiromoana Bush and as a result possum numbers are very low. It is intended that this operation will continue for the foreseeable future. The effectiveness of possum control will be monitored through assessing biodiversity response. Should monitoring indicate that the current level of possum control is insufficient to sustain biodiversity values then the current possum control operation will be reviewed.
Stoats, ferrets and weasels (mustelids): Mustelids are likely to be widely distributed, although probably at low numbers. Numbers will also fluctuate considerable between years depending on food availability. Mustelids are a direct threat to biodiversity values, especially native birds and larger invertebrates, and are also implicated in the transmission of bovine Tb. Some ferret control occurs as part of the bovine Tb control programme and further mustelid control will be undertaken should bird monitoring indicate high predation.
Rats: Rats directly affect biodiversity through predation of fauna and also impact upon plant regeneration processes through seed predation. Rats are presently not controlled in Tiromoana Bush, but control will be undertaken should bird monitoring indicate high predation.
Hares and rabbits: Hares and rabbits constitute a direct threat to restoration plantings. Unfortunately hares in particular are difficult to control, but these pests will be controlled as impacts dictate. Impacts will also be minimised through the use of appropriate retardant pastes or protective collars on restoration plantings. Hare and rabbit impacts will be directly monitored as a part of restoration monitoring and control will mostly involve shooting (especially for hares).
Feral deer and goats: Feral deer (red and fallow) and goats are likely to be present within the general area, and to pass through Tiromoana Bush from time to time. These species can cause damage to biodiversity values, and also pose a threat to restoration success. Control will be opportunistic in nature, and will involve hunting when animals are known or thought to be present.
Vespulid wasps: Wasps are present primarily in beech forest remnant and constitute a threat to biodiversity values (in particular native birds and invertebrates) within this area through competition for food resources and predation. They also constitute a direct threat to health and safety of people working in the area. Control will involve the active seeking out and locating nests and treatment with a suitable poison each summer.
Feral cats, feral dogs, feral pigs, hedgehogs and mice: These animals are either known to be present in Tiromoana Bush, but difficult to control (mice and hedgehogs), or may occasionally be present in the general area (feral cats, dogs and pigs) and as such may spread into Tiromoana Bush. Control will not be implemented directly for these species although it is expected that feral cats, hedgehogs, and mice will be caught as a consequence of other control programmes including those associated with the landfill. Should feral dogs or pigs be seen they will be actively hunted. Dogs will be prohibited from the Kate Valley CMA walking tracks.
All plant pest control will meet national and regional legislative requirements, especially any obligations imposed through the Regional Pest Management Strategy, and will follow best-practice guidelines. All staff involved in weed control work will be required to have appropriate licences for handling any chemicals involved. Details of the methods to be used for plant pest control will be developed with the contractors undertaking the work and will be based on current best practice guidelines.
Woody weeds: These are weed species that are known to cause problems in similar environments and therefore pose a threat to biodiversity values, including restoration plantings, at this site. Woody weed species known to be present in Tiromoana Bush include wilding conifers, European broom, hawthorn, willow, blackberry and old man’s beard.
Three main approaches will be taken to prevent the establishment and spread of unwanted woody weed species in Tiromoana Bush:
Pasture grasses and herbs: Pasture grasses and herbs are efficient competitors for water, as well as nutrients and light, and can restrict the growth of new plantings. However, there is little likelihood that any of these species can be eliminated from Tiromoana Bush, while the regenerating forest will eventually suppress them from most sites. Control will therefore focus on removing them prior to the establishment of restoration plantings and restricting their re-establishment and growth until restoration plantings are tall enough to shade them out.
Gorse: While widely regarded as a plant pest, gorse offers considerable potential as a nurse species for restoration of indigenous forest. Gorse has been used successfully in this capacity at Hinewai Reserve on Banks Peninsula (Wilson 1994) and it is proposed that gorse will play a similar role in the Tiromoana Bush Restoration Project. Gorse will be used as a nurse plant because of the high costs associated with controlling gorse and of implementing an active planting programme covering >100 ha, and the known ability of gorse to invade rank grassland and provide a suitable environment for indigenous forest regeneration. However, gorse also presents a considerable fire risk and a key component of restoration management is to vigorously maintain a total-fire ban within Tiromoana Bush.
Wilson, H.D. 1994. Regeneration of native forest on Hinewai Reserve, Banks Peninsula. New Zealand Journal of Botany 32: 373-384.
Invasive plant and animal species are widely regarded as the single biggest threat to New Zealand’s indigenous biodiversity. These invasive species also threaten restoration projects such as that at Tiromoana Bush as invasive weeds can out-compete and suppress plantings, while invasive animals browse plantings and seriously impact on key pollinators and dispersers in the surrounding forests.
Domestic stock were removed from Tiromoana Bush at the outset of the restoration project. This involved upgrading existing fencing and the installation of new fencing, with all domestic animals then mustered out of the area. All fences are maintained to a standard to ensure that stock are not able to readily re-enter the area and all gates are locked to ensure that they are not left open accidentally.
A number of introduced animal pests including brushtail possums, stoats, ferrets, rats, mice, red and fallow deer, goats, rabbits, hares, pigs, hedgehogs and vespulid wasps are likely to be present or border upon Tiromoana Bush. Domestic and feral dogs and cats may also come onto the site. The presence of both wild and domestic animals within Tiromoana Bush will impact upon the restoration work. The objectives for animal pest management are to reduce the impact of herbivores on the restoration plantings, and the impact of herbivores and carnivores on indigenous plant and animal species within regenerating forests.
Weed species present a very real threat to the success of any restoration programme as they can out-compete the planted species resulting in reduced growth rates and mortality. However, it needs to be acknowledged that for gorse at least, the eventual succession appears to be to indigenous forest. However, several other species of weed are a direct threat to restoration (both plantings and natural regeneration) and the highly modified nature of Tiromoana Bush means that these species are already present in large numbers. The objective of weed management is therefore to maintain Tiromoana Bush free of all priority weed species.