Impact 2 - Management
St. John’s wort - the subject of the first biocontrol cost–benefit study in New Zealand
Best solutions are identified that integrate economic, social, cultural, and environmental initiatives to maintain or enhance international competitiveness, market access, and social licence for business and industry to operate.
Indigenous forestry
The extraction of timber from New Zealand’s beech forests has been one of the most controversial environmental issues over the last half century. To provide greater clarity, we reviewed and summarised nearly 20 years of research and experience in implementing beech management systems (allowed for under Forests Act provisions and implemented through MPI’s standards and guidelines). The review covered the influence of current harvest systems on tree recruitment, growth and mortality and other natural values such as biodiversity, biological invasions, nutrient cycling, and carbon storage.
Because of our experience in indigenous forestry, we and Lincoln University were invited to host the 8th IUFRO International Conference on Uneven Aged Silviculture, the first time the conference has been held in the Southern Hemisphere. Economical returns from uneven-aged silviculture (exotic and indigenous) can equate to or exceed those of even-aged silviculture, while safeguarding the multiple non-timber services associated with forests (e.g. biodiversity, clean water, recreation and tourism, hunting).
As in many countries, indigenous forests are ‘cultural landscapes’. We continue to work with Tūhoe on their Sustainable Forest Management Plan that includes strategies for extracting high value native tawa trees to both create unshaded space for and fund the restoration of native podocarp species with higher cultural value.
Owners and managers of indigenous forests, many of whom represent Māori organisations, are using our research to identify risks to their sustainability credentials and evolve their management systems to mitigate such risks. This should expand access to high-value markets for forest owners and favour indigenous timber production.
This research is part of the Realising Land’s Potential portfolio, and was supported by Core funding, MBIE contestable funding and MPI. The restoration forestry work in the Urewera has had considerable in-kind support from the Tūhoe Tuawhenua Trust.
Sustainability of pastoral agriculture
We contributed to a review of international sustainability assessment schemes for pastoral agriculture, with a focus on measurement tools for value chains and individual beef and sheep farms. We developed and recommended specific indicators for environmental footprint capability (focused on biodiversity) for the FarmIQ database, which will enable the beef and sheep sector to better understand their sustainability performance, manage and report this publicly, and hence sustain their ‘licence to operate’ from the community. The work has been carried out in collaboration with the New Zealand Life Cycle Management Centre.
This research is part of the Supporting Trade portfolio, and was supported by Core funding and Silver Fern Farms.
Helping ZESPRI®’s international competitiveness
Landcare Research has assessed the methods used in French eco-labels for kiwifruit and how Zespri’s own work could be used to answer queries by French retailers and consumers. The research involved using the latest techniques – a consensus on different footprinting methods determined by international life cycle experts – to compare the compatibility of the footprint methods used in the two countries. Whenever possible, the research updated the previous Zespri studies with new data. Results show methods used to complete the carbon footprints by Zespri and French eco-labelling trial are compatible but the water footprint methods are not because the French methods are too different. Zespri will use the work to understand its relative position across reported metrics and to inform decision making on strategies to further enhance the environmental credentials of its products.
This research is part of the Supporting Trade portfolio, and was supported by Core funding and ZESPRI® International.
Botrytis in grapes
Botrytis bunch rot is the most important disease of grapes in New Zealand. To minimise fungicide use, current models for managing disease risk are based on knowledge of how disease development is affected by season, climate and vineyard management. However, our recent research is the first to investigate the genetic diversity of Botrytis within New Zealand’s vineyards. Understanding this diversity is important because Botrytis species are known to differ in both pathogenicity and fungicide resistance.
We showed that two species are present in New Zealand vineyards, the highly pathogenic B. cinerea and the less pathogenic B. pseudocinerea, which is naturally resistant to the important fenhexamid fungicides. All isolates that showed fungicide resistance were B. pseudocinerea, which shows that the New Zealand wine industry is managing the use of this fungicide effectively and avoiding the resistance problems that could make the fungicide unusable.
The work also showed there are regionally distinct, subspecific populations within B. cinerea that differ in pathogenicity. Although the practical impact of this is yet to be explored, existing disease risk management models used by the wine industry may need to be modified to allow for these regional differences.
This research is part of the Supporting Trade and Defining Land Biota portfolios, and was supported by MBIE contestable funding subcontract from Plant & Food Research. The PDD fungi collection is Core-funded.
Fighting Psa disease in kiwifruit
The emergence of pandemic bacterial diseases such as Pseudomonas syringae pv. actinidiae (Psa) poses significant risk to all the main areas of kiwifruit production in the world. At the time of the Psa outbreak in New Zealand, we worked with ZESPRI/ Kiwifruit Vine Health (KVH) and MPI, using our International Collection of Microorganisms from Plants (ICMP) to identify the Psa disease affecting Bay of Plenty kiwifruit. Since then, we have analysed samples from 61 orchards (over 2400 leaves surveyed) – first by culturing the causal bacterium, followed by DNA sequencing, to determine the within-species ‘pathovar’, and within that the virulent strain of concern. We are now working on methods to control Psa. Bacteriocins are narrow-spectrum antimicrobials, produced by bacteria to kill closely related competing bacterial species or subspecies. The narrow-spectrum nature of bacteriocins make them particularly attractive as a disease control agent as they are less likely to create broader antibiotic resistance in the wider microbial community, as well as posing a low residue risk for food products. The ICMP collection has been screened for species capable of producing bacteriocins as potential controls. Industry partners (ZESPRI and Comvita) have already expressed interest in the approach.
This research is part of both the Supporting Trade and Defining Land Biota portfolios. Psa investigations were supported by Core funding, MPI and commercial services to KHV. The ICMP (International Collection of Micro-organisms from Plants) is supported by Core funding. Bacteriocins investigations are supported by MBIE’s Pre-Seed Accelerator Fund and Landcare Research commercial Investment.
Systematics tools for biosecurity
We also used the ICMP and DNA sequences to provide MPI with a barcoding tool for rapid, accurate identification of Colletotrichum – one of the top 10 most important disease-causing pathogens in the world. The very high quality of this database means that it is suitable for use by biosecurity officers. Without the barcodes, it is notoriously difficult to identify the species associated with each disease. The Colletotrichum DNA barcode database is an ongoing collaboration between Landcare Research, CBS (The Netherlands), CABI (United Kingdom) and the International Subcommission on Colletotrichum Taxonomy.
We provided Danish collaborators with specimens and DNA sequences, enabling them to confirm the identity of the new apple disease ‘Topaz spot’. Plant pathologists worldwide and biosecurity regulation agencies in New Zealand can now better understand the fungal diseases of modern apple cultivars, and their distribution.
This research is part of both the Supporting Trade and Defining Land Biota portfolios. The ICMP (International Collection of Micro-organisms from Plants) is Core funded. Development of the database was supported by Core funding and AGMARDT.
Halving the cost of large-scale control
Aerial baiting is often the only affordable way of alleviating the problems caused by possums and rats in large areas of native forest. For slow-breeding possums, 90–99% reductions in possum density are often achieved, resulting in low numbers for up to 10 years. However, as rat numbers can bounce back within 1–2 years, more frequent control is sometimes desirable but would increase costs. First, we confirmed that sowing baits in narrow strips is as effective for pest control as wide swaths. Then using fixed-wing aircraft (which cost less than helicopters), we showed that, provided the baited strips were no more than about 100 m apart, possums and rats could be controlled effectively but at significantly reduced cost. DOC, Aorangi Trust and AHB (TBfree New Zealand) are now designing a 10-year programme of low-cost aerial baiting every 2–3 years (instead of every 5 years) to determine whether TB could be eliminated from possums at the same time as markedly improving rat control, and, consequently, biodiversity outcomes at little extra cost.
This research is part of both the Supporting Trade and Managing Invasive Weeds, Pests and Diseases portfolios, and was supported by MBIE contestable funding and AHB (now TBfree New Zealand).
Improving rabbit control
We have significantly refined current practices for rabbit control using aerial application of 1080. Field trials completed in Otago (winter 2011 and 2012) showed reduced per-hectare amounts of bait sown in strips can achieve effective rabbit control, with cost savings of about 40% over current ‘total cover’ baiting practices. Further trials with bait sown in strips were undertaken in winter 2013.
Carrot bait quality, i.e. uniformity of bait size and toxin concentration, has been identified as a critical factor in the success of rabbit baiting operations. However, producing carrot bait of a uniform size is difficult. We have worked with Otago Regional Council to improve bait quality but current manufacturing practices cannot entirely prevent small carrot fragments (chaff) being produced. Chaff may be sub-lethal to rabbits. Consequently, our strip-sown design aims to maintain high bait density in the strip to maximise the likelihood that rabbits find and consume plenty of baits, to avoid sub-lethal effects. Although there is potential to further improve uniformity in bait size, we suspect that improvements to date will already have reduced potential risks of primary poisoning non-target species.
This research is part of both the Supporting Trade and Managing Invasive Weeds, Pests and Diseases portfolios, and was supported by MPI and in-kind support from Otago Regional Council.
Cost–benefit analysis of weed biocontrol
We completed a biocontrol cost–benefit study, the first in New Zealand, of the highly successful programme against the weed St John’s wort. A model of the potential spread of St John’s wort suggested that without biocontrol, 660 000 ha of South Island hill-country pasture would become badly infested. The annual cost of lost grazing to farmers was calculated to be $109 per hectare, with a smaller annual cost of $6 per hectare for manual weed control. The Net Present Value (NPV) of the introduction of beetles as a biocontrol agent was between $140 million (given a conservatively slow rate of spread) and $1490 million (with a faster rate of spread) over 70 years. The benefit-to-cost ratios were an impressive 10:1 and 100:1 respectively. The savings provided by the St John’s wort biocontrol programme, even at the lower end, more than pay for all the other weed biocontrol programmes undertaken in New Zealand to date.
This research is part of both the Supporting Trade and Managing Invasive Weeds, Pests and Diseases portfolios. The analysis was supported by Core funding and used research supported by MBIE and its predecessors.