A Cape to City conservation success story
It’s one of the largest wildlife restorations in New Zealand, and Cape to City programme leaders are optimistic the Hawke’s Bay project will become a template for large-scale renewal of New Zealand’s unique biodiversity.
Predator control and ecosystem restoration are usually confined to small-scale reserves and sanctuaries, but Cape to City is anything but small. It encompasses 26,000 ha of private and public land between Havelock North and Waimarama Beach, involving 120 land holders, and most of it is productive farmland. It aims to allow native species to thrive where people live, work and play in order to achieve biodiversity, economic and social gains.
The $6 million jointly funded collaboration has brought together the expertise and know-how of the Aotearoa Foundation, Hawke’s Bay Regional Council, Department of Conservation and Landcare Research. Another collaborator, Cape Sanctuary, also contributes $0.6 million annually on wildlife restoration to extend suitable habitat for wildlife beyond the sanctuary so that native birds can fly out and flourish. An extensive research platform underpins activities, and this allows for an evidence-based approach to management, documents the results of work in peer-reviewed literature, and involves the training and development of students.
The work also builds on a pre-existing predator control programme called Poutiri Ao ō Tāne. Located in Hawke’s Bay around the Boundary Stream public reserve, this programme showed that wildlife in scattered bush remnants could be protected if predator control was widespread (8000 ha). But in order to scale-up to 26,000 ha, predator control needed to be cheaper: about $3 per hectare for maintenance control.
Clearly, a strategy focused on the correct target and selective enough to meet a tight budget was needed to ensure the project would be successful. The project team drew on their previous experience and knowledge and made a deliberate decision not to reinvent the wheel. Kill-traps were used across the Cape to City area – their target, feral cats, stoats, ferrets and hedgehogs. Rats were controlled only in selected areas rather than all 26,000 ha, and one of the big success stories came via the use of electronic nodes. Attached to each trap, they sent signals to a satellite and then a land holder’s cellphone, providing the locations and time traps had been sprung.
Former Federated Farmers president Bruce Wills, who is on the Cape to City board, said time-efficient methods such as trap-related cellphone alerts created excellent buy-in from farmers. They knew their time was being used wisely. They also knew that even if their neighbour chose not to participate in the project, they were still making a difference.
This knowledge was acquired from Landcare Research scientists, who generated computer models that revealed what would happen if some landholders did not participate in the predator control programme. The model showed that this had little, if any, impact on the programme if correct trap densities were employed to maximise captures.
It is essential to know that the trapping programme is successfully supressing predator numbers, but monitoring predators on such a large scale is inherently challenging. Methods championed by Landcare Research, such as motion-triggered cameras that track predators in areas with and without predator control, have been used to provide robust data and estimates of predator numbers.
The numbers of birds, lizards and invertebrates in the pest control zone, and in a large non-treatment area nearby, were also measured using modified 5-minute counts, artificial refuges, tracking tunnels, tree wraps and weta houses. Exploratory work is running alongside, comparing a potentially cheaper method of biodiversity monitoring, called ‘environmental DNA’, with other standard methods (pitfall trapping and malaise traps). This information will help Predator Free New Zealand operations, and will inform land holders and pest management agencies how well native plants and animals might recover in farmland and other productive land. Some of this monitoring is also taking place in restored habitat along the Maraetotara River to gauge fauna recovery resulting from both habitat enhancement and predator control. The Maraetotara Tree Trust, with support from Hawke’s Bay Regional Council (HBRC), plant massive numbers of native species along this river every year to restore corridors for wildlife. Hopefully, predator control will not only help wildlife already in the area to recover, but also native birds, such as robins and tomtits, that fly out and live nearby every year. Previously these emigrants stood little chance of survival outside the sanctuary in a hostile environment full of predators. The Department of Conservation are also translocating robins, tomits, pāteke (brown teals) and petrels into areas where predators have been controlled. The survival of these species is an important litmus test of the success of the predator control programme. HBRC biosecurity advisor Rod Dickson said lizard and weta numbers at Poutiri Ao ō Tāne had ‘gone through the roof’ since pest control began. "We’ve already started to see tomtit and robin turn up at Te Mata Peak [from Cape Sanctuary]." Dave Carlton, Department of Conservation Hawke’s Bay operations manager, said, "We’ve seen an increase in the amount of lizards and invertebrates in the surrounding landscape [around Boundary Stream Reserve]." This included birds such as kākāriki, kākā and pāteke. "It’s a bit of a window into what might happen with Cape to City," Carlton said.
There have been other welcome benefits. One such tangible example is directly helping the farming community. Toxoplasmosis is a disease spread by feral cats that causes abortions in sheep. It costs sheep farms in Hawke’s Bay $336,000 each year in vaccination costs and an estimated $1,032,180 each year in lost lamb production. The effect of cat control has yet to be fully quantified, but early evidence suggests inroads are being made. As a result, toxoplasmosis levels in sheep have become an important part of the research programme and farmers are taking a keen interest in the results. One of the other main objectives of the programme is to inform and involve the community in biodiversity protection. Landcare Research social scientists are trying to understand why people become interested in biodiversity and what motivates them to get involved in protecting it. Throughout the programme land holders and the general community are being surveyed to monitor changing attitudes to biodiversity and levels of participation compared with areas outside Cape to City. In order for other agencies to emulate the successful components of the programme, and to learn from its mistakes, Landcare Research is also documenting the programme as a case study by recording the opinions of the key players who manage and implement the various projects.
NOTES ON FUNDING: Landcare Research allocated $700,000 of MBIE Strategic Funding to the Cape to City research programme. Other key funding sources included: Aotearoa Foundation ($2.3 million), Hawke’s Bay Regional Council ($1.5 million) and Department of Conservation ($1.6 million).