Research highlights
Tree weta indicate the effectiveness of sustained rat control
Future of pest management processes
During 2009/10, Landcare Research scientists played a substantial role in a process, instigated by MAF Biosecurity New Zealand (MAF BNZ), to identify the best, future directions for pest management. Our staff were involved in three of the working groups, including the lead drafting group. The process culminated in the release, in June 2010, of a discussion paper proposing a new national plan of action for pest management for 2010–2035. Our input was both strategic and technical, providing the ‘reality checks’ between high–level–policy aspirations and what is actually achievable within the constraints of pest ecology and pest management in practice.
Contributing to future freedom from bovine TB
New Zealand has made major progress in reducing the levels of bovine tuberculosis (TB) in farmed cattle and deer. There are now fewer than 100 infected herds compared to about 1,700 just 15 years ago. The Animal Health Board (AHB) has therefore proposed a new national pest management strategy (NPMS) for TB that aims for local and regional eradication of TB from both livestock and possums (the main wildlife host) by 2026. This goal is endorsed by farmers, industry and local and central government who want to protect our reputation as a supplier of safe, high quality meat and dairy products.
Landcare Research’s work for the AHB has contributed substantially to the success of the current NPMS, which is on track to achieve fewer than two in a thousand herds (0.2%) infected by 2013. The emphasis now is on local eradication of TB from wildlife – decreasing the cost of reducing possums to very low density while also reducing the amount of poison used, developing alternative methods for breaking the TB cycle, and developing new tools for quickly showing TB has been eradicated locally so that possum control can be stopped.
Significant projects are being conducted in two remote high country stations, the last areas in northern Canterbury where TB levels in cattle and wildlife had been high. A large–scale aerial poisoning operation in 2008 piloted two new approaches – targeting high–possum–density areas predicted to have the highest risk of TB–infected animals, and a new low–cost, low–toxin approach to 1080 poisoning. This year, the number of infected cattle has dropped by 88%, very pleasing after 18 months. In addition pigs, which are highly susceptible to infection when TB–infected possums are present, have been deliberately released in the area as sentinels for detecting TB. Few sentinel pigs inside the managed areas have become infected, compared with most of those in an unmanaged area.
In an additional management approach, which is being developed in collaboration with AgResearch and Otago Innovation, a vaccine (BCG) used to protect humans from TB is also showing promise in protecting free–ranging cattle from the natural sources of TB in this area. For one group of study animals, none of the 86 cattle in the vaccinated group tested positive for TB a year after vaccination, compared with 5 (10%) of 53 that were not vaccinated. Vaccination of cattle may therefore be useful as an interim tool for reducing TB in livestock in areas where it is impractical to undertake effective control of possums.
Outcome–focussed performance monitoring
We have been working with MAF BNZ to develop an effective outcome–focused performance monitoring framework for pest management because it had become increasingly obvious that current approaches are highly inconsistent, often with poorly defi ned outcomes and little in the way of robust monitoring to determine actual benefits of control programmes. Following 20–plus stakeholder–engagement meetings around the country with MAF BNZ, pest control agencies and end–users, work focused on developing structured performance indicators for high–level national pest management outcomes and implementing the early stages of a framework for goal setting, monitoring and data standards.
We also lead a technical advisory group that is developing performance indicators aligned with the Department of Conservation’s (DOC) Natural Heritage Management System (NHMS) and other measurement systems. The group is made up of DOC, AHB, MAF BNZ, Statistics NZ, regional councils and experts in economics and social indicators.
A new project with MAF BNZ will extend the ‘Performance Measurement Framework’ project to review performance measures, and develop new performance indicators for the Didymo national management programme, and a monitoring and evaluation strategy for a new long–term management programme for kauri dieback. Both of these involve working with multiple agency/stakeholder groups.
Developing a pest management decision support system
A new pest management Decision Support System (DSS) is being developed with Envirolink Tools funding. The draft version of the web–based DSS, released earlier this year, was strongly endorsed by the regional councils’ Biosecurity Managers Group. While the development was initially driven by the needs of local authorities, the tool will be freely available. It is likely to find use throughout the pest ‘sector’. The DSS takes account of operational aims, previous control, land tenure, farming practice, public and environmental safety, community views and involvement, and landowner views. Simple ‘yes/no’ responses at each step make the system intuitively easy to understand and provides unambiguous options for the most appropriate control.
All recommendations are linked to best–practice advice in accordance with DOC and National Possum Control Agencies (NPCA) guidelines, and supported by research fi ndings. New information from research, field practice and manufacturers will be incorporated on an ongoing basis.
Monitoring weta highlights the effectiveness of pest control
Introduced pest mammals pose a signifi cant threat to biodiversity conservation in New Zealand. To understand the benefits of controlling individual pest species, a greater ecosystem–level understanding of interactions between multiple pest species is required.
This year, we completed a large, four–year research programme into species interactions and the consequences of pest control at the ecosystem level. One of the indicators chosen to measure the effectiveness of pest control, especially sustained rat control, was numbers of tree weta. Initial control of possums and rats using 1080, then ongoing ground–based rat control using Ditrac (diphacinone) in bait stations, prevented rat populations bouncing back (as happened in sites with no ongoing control). Tree weta flourished in the continued absence of rodent predation making them a good alternative to monitoring birds to show biodiversity benefits from pest control. Weta are engagingly iconic, easy to monitor, and respond reasonably quickly to reduced rat populations.
Kauri dieback – caused by Phytopthora taxon agathis (PTA)
Dieback of kauri trees is associated with an as yet undescribed species of Phytophthora – a microscopic group of fungus–like, plant pathogens. Our research indicated the pathogen could be transferred from diseased to healthy trees in soil (including that on shoes, tyres, and plant equipment), and that Trigene II Advance® was the most effective disinfectant against the pathogen.
This year, in our surveillance work to map the disease, we found it in Northland’s Waipoua Forest close to Tāne Mahuta (New Zealand’s most iconic and venerable tree). Additional funds were allocated by Cabinet to be overseen by a consortium of MAF BNZ, DOC and several northern regional councils. Our research for the consortium is focused on developing robust, reliable, diagnostic techniques (both tree– and soil–based detection), surveillance, a greater understanding of how the pathogen is spread, appropriate management and containment strategies, and finding an effective control.
The Phytophthora group of pathogens are of immense economic and environmental significance around the world. In March 2010, we co–hosted the Fifth International Union of Forest Research Organisations (IUFRO) meeting on Phytophthora Diseases. The conference provided a very useful forum for researchers, regulators and end–users to discuss and debate PTA and its implications on kauri forest ecology and management.