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Current state of biosecurity in NZ – Expert Q&A

Even though one virus has caught the world’s attention this year, efforts to keep New Zealand’s ecosystems safe from other pests haven’t stopped.

The SMC asked experts to comment on what they think are New Zealand’s biggest biosecurity concerns, and how the COVID-19 pandemic has affected their research. These fields include:

  1. Overall views of NZ’s biosecurity threats
  2. Myrtle rust
  3. Marine biosecurity
  4. Freshwater

Associate Professor Margaret Stanley, School of Biological Sciences, University of Auckland, comments:

What are the biggest concerns for New Zealand’s biosecurity right now?

“Well-known pests: Rapid ‘Ō’hia Death is said to make myrtle rust look like a day at the beach. This fungal disease is causing catastrophic and widespread mortality of metrosideros (‘Ō’hia) forests – closely related to NZ’s pōhutakawa. This disease, transmitted by a beetle, is one we do not want in Aotearoa.

“Small organisms, especially those not pests elsewhere: In general, the biggest biosecurity threats hitting our borders now and into the future are organisms that are small and difficult to detect – usually invertebrates and pathogens. For well-known pests overseas, like brown marmorated stinkbug, we can be well-prepared in advance to search and destroy. However, with organisms that aren’t pests overseas or are new to science, like the pathogen that causes kauri dieback, or the liberibacter bacteria that causes zebra chip potato disease, it’s quite difficult to know we’ve got a problem until the organism has spread far and wide. We also usually don’t have the tools or knowledge to detect and control the organism.

“Climate change will bring more pests to our shores: Changing weather patterns and more frequent storm events are likely to bring more wind-borne diseases and insects to Aotearoa, similar to the arrival of myrtle rust from Australia. An excellent general surveillance system will be vital for early detection of these pests. Climate change also brings uncertainty about whether organisms will establish and spread in Aotearoa, with fewer frost days and other changes to our environment perhaps making Aotearoa more inviting to tropical pests.

“Weed explosions inside NZ: We have an ‘invasion debt’ of weeds in Aotearoa. We have introduced more than 25 000 plants from overseas over the last couple of centuries, and although we have strict laws on bringing new plant species into Aotearoa, each year about 20 of the existing introduced species ‘naturalise’ and are able to grow in the wild. So while we only have about 2 500 native plants, we have the same number of introduced plants growing in the wild, and this number is growing each year. Some of those plants go on to become weeds (currently > 400), so we have a continuous, insidious conveyor belt of plant species escaping from people’s gardens and the productive sector, and becoming weeds. Unfortunately, weeds are the poor cousin to other biosecurity threats, and it’s hard to sell the extent of the threat when we have immediate and obvious threats to our native birds from pest mammals.”

How has the pandemic affected biosecurity research, for better or worse?

“There are positive aspects to the pandemic for biosecurity. There are certainly a lot fewer people coming across our borders, and this lowers the risk of pest incursions. However, the most positive aspect of the pandemic is the science communication! Now New Zealanders are familiar with the epidemic curve and understand concepts such as ‘flatten the curve’. The epidemic curve is very similar to the pest infestation curve, which we use to explain the status of various pests (from newly arrived to widespread) and which management actions should take place at various places along the curve.

“Although there are differences in terminology used in epidemiology (e.g. use of elimination vs eradication), this new-found knowledge that New Zealanders have makes it easier for us to communicate that eradication is most suited for newly-arrived pests that aren’t yet widespread, while for widespread species we should focus on protecting our assets, such as conservation areas. We’ll need to build on this pandemic communication platform for biosecurity.”

No conflict of interest.

David Teulon, Director, Better Border Biosecurity (B3), comments:

“COVID-19 as a biosecurity event has reminded us and reinforced how critically important it is to protect our border from invasive species. However, as well as protecting the borders, we must also plan for biosecurity events before they happen and how we can manage any incursions in the long term if they establish here. There is no question that plant biosecurity can learn much from COVID-19 and vice versa.

“COVID-19 has focused our attention on how our wellbeing and the health of the economy rely on Aotearoa New Zealand’s animal and plant systems, and emphasised the need to protect them from invasive species. Right now, we simply cannot afford to have any new major disruptions from invasive species – similar to PSA or Mycoplasma bovis – because our primary industries will be vital in pulling us through this period of economic disruption and uncertainty.

“The global supply chain disruption brought on by COVID-19 does, however, appear to have reduced the number of plant pests and pathogens crossing our borders. The number of notifications (and consequential investigations) of biological risk in the plant health and environment area were down from 167 in March 2019 to 105 in March 2020. This is a notable and substantial reduction, particularly as biosecurity was considered an essential service throughout lock-down and our border services were busy throughout looking for unwanted invasive species.

“The Better Border Biosecurity (B3) research programme has been significantly impacted by COVID-19. Because our work focuses on pest, pathogen and weed species not found in New Zealand, much of our research is carried out overseas. Our institutes were proactive and stopped international travel by researchers in February 2020 and international travel is not an option for the foreseeable future. This means several important pieces of research on significant pests and pathogens could not be completed as planned. Of note was our inability to assess the impact of the invasive pathogen Xylella fastidiosa on New Zealand native plants in California. Also delayed was research in Australia necessary to evaluate the usefulness of new lures to detect fruit flies and other work to generate markers that allow us to distinguish the geographic origin of fruit flies intercepted in New Zealand. A major project assessment of pests in China that could threaten our pasture industry was also delayed.

“Fortunately, most of our researchers were at home at the time of lockdown. But there have been cases of non-resident students working on biosecurity topics with international experts being stuck in another country due to border closures. The B3 Conference scheduled for May 2020 has been rescheduled to May 2021, but, was largely replaced by a series of very useful virtual meetings.

“Like for everyone else, the B3 future under COVID-19 is uncertain and we need to adjust to a new way of doing things. Many of our research projects require international work and whether we will be able to undertake these in the near future, or how we might practically engage with overseas researchers as part of an extended team, is not at all clear. We are reviewing all projects on a monthly basis and exploring alternative ways of doing things where possible, necessary and available. The B3 programme team are all committed to their part in keeping new pests, pathogens and weeds out of New Zealand, and understand their increased responsibility and need to respond creatively at this time.”

No conflict of interest.

Dr Craig Phillips, Senior Scientist, AgResearch, comments:

“Identifying and ranking biosecurity threats to New Zealand is difficult and imperfect, but is nevertheless critical to an effective biosecurity system. Sometimes non-native pests that are having major impacts in New Zealand have come from left-field, in the form of species that we don’t hear much about from overseas. It is important therefore to analyse the risks presented by a wide range of organisms, and avoid the mistake of assuming species which currently dominate the headlines overseas – like brown marmorated stink bug and fall armyworm – are our only threats.

“An example of a left-field threat to New Zealand livestock farming includes some sawflies, whose larvae generally feed in trees on the leaves. Damage to shelter belts and trees planted for erosion control are obvious possible impacts, but sawflies can create even worse headaches. Overseas the larvae of some sawflies are eaten by livestock, when either the larvae fall to the ground to pupate, or when livestock browse the leaves. Unfortunately, the larvae of some sawflies are fatally toxic to livestock, and a sawfly in South America even has the nickname ‘pig killer’.

“Some biosecurity hazards could cause problems for numerous sectors in New Zealand, including our conservation estate and agricultural industries. The Department of Conservation recently eradicated great white butterfly from New Zealand because it was a threat to New Zealand’s many endemic brassicas (like Cook’s scurvy grass), but if not eradicated, it would have become a problem for vegetable growers and farmers who grow forage brassicas too. Ants such as red imported fire ant and tropical fire ant would also cause problems for the conservation estate and farmers alike.

“It seems probable that the COVID-19 pandemic and resulting border closures will have reduced our biosecurity incursion risks to some degree because currently far fewer people are coming to New Zealand from overseas. However, I think it would take a years-long border closure – which I certainly hope does not eventuate – to see any real change in pest invasion rates in New Zealand. This is partly because it has long been easier to effectively manage biosecurity risks from incoming passengers than from large-scale importations of goods in shipping containers and items like cars and machinery, which will have declined less due to the pandemic. Indeed, incoming freight is an area where we most need new technologies to help us keep unwanted pests out of New Zealand. Imports of plants and plant products are also major risks, but like incoming passengers, more options are available for managing them.”

Conflict of interest statement: I have worked with DairyNZ to evaluate biosecurity risks to plants that are important to NZ dairy farmers, and am involved in Better Border Biosecurity ( projects evaluating risks to the conservation estate.

Dr Stuart Fraser, Assistant Research Leader, Pathogen Ecology and Control, Scion, comments:

What is the current state of play around myrtle rust research and eradication efforts in New Zealand?

“Within a year of its arrival to New Zealand in 2017, the disease was recorded in many regions of the country. Eradication efforts were therefore stopped at this point, and research focussed on supporting long-term management. Eradication of the pathogen was always going to be difficult, given its broad host range and the ability of its spores to spread widely and rapidly in wind. Early detection of invasive pests and pathogens is crucial if we are to have any chance of eradication. This is why it is so important for people to be aware of biosecurity threats and for practitioners to have socially acceptable tools available to attempt eradication quickly.

“Research is currently being undertaken within two MBIE-funded programmes, Beyond Myrtle Rust and Ngā Rākau Taketake. Within Beyond Myrtle Rust, research focuses on four themes: the adaptability of the pathogen, the ecosystem impacts of the disease, novel control tools, and Māori solutions. My own research in this programme at Scion focuses on the adaptability of the pathogen. We have already found evidence that the pathogen is reproducing sexually, as well as clonally, in New Zealand. This will complicate management of the disease, as sexually reproducing species are more adaptable due to rearrangement of the genome between generations. They are better able to overcome host resistance or control tools. Our research now focuses on how widespread and important this process is and what environmental and host conditions encourage it.

“Early research within Ngā Rākau Taketake undertaken at Scion has investigated the susceptibility of different native species to the disease and the impact the disease is having in native forest. Early results demonstrate that pōhutukawa, ramarama and rōhutu are all susceptible to infection. But, so far, we have seen no infection of mānuka or kānuka in our trials, suggesting they may be more resistant species.

“Monitoring in native forest in the Rotorua area has demonstrated the impact the disease is already having on populations of Lophomyrtus (ramarama, rōhutu, and their hybrids). The disease affects flowers, fruits and young foliage of these species, causing death of seedlings, dieback of older plants, and loss of fruits to produce the next generation. Research must be expanded to investigate the impacts the disease is having on other species of Myrtaceae and in other areas of the country to prioritise management.

“Research in other areas of both programmes aims to find solutions. For example, identification of mechanisms that make plants resistant, understanding what makes ecosystems more resilient, and characterising the microbial communities that live in plants and may contribute to their health (much like the microbes that live on our skin and in our stomachs).”

No conflict of interest.

Mahajabeen Padamsee, Research Mycologist, Manaaki Whenua Landcare Research, comments:

What is the current state of play around myrtle rust research and eradication efforts in New Zealand?

“We know from the history of this disease, that myrtle rust has never been successfully eradicated and in April 2018, the Ministry of Primary Industries (MPI) that had been managing the incursion moved to long-term management of the disease. The current research on myrtle rust is being mainly conducted by a Ministry of Business, Innovation and Employment (MBIE) Endeavour programme, “Beyond Myrtle Rust: Towards Ecosystem Resilience” (BMR), that is a multi-organisational collaboration led by Manaaki Whenua, and by a second programme Ngā Rākau Taketake – Saving our Iconic Trees, that is led by the BioHeritage National Science Challenge.

“BMR is aiming to understand the pathogen in the New Zealand ecosystem to predict/record the impacts of the disease on New Zealand ecosystems, develop new tools to manage the disease, and to enhance Māori solutions to the disease. There is open sharing of information that is achieved through BMR to the wider research community.”

What are the major concerns/opportunities on the horizon in this field?

“A major concern is that we are in a race against the pathogen. We need to understand why certain plants are more susceptible than others, record baseline data from ecosystems, and find ways to control the pathogen before myrtle rust spreads further. We have a great opportunity ahead as the myrtle rust research community is collaborative and actively seeks ways to work together to mitigate the effects of this pathogen. Additionally, we are passionate about protecting our myrtles such as pōhutukawa and mānuka in Aotearoa.”

How has the pandemic affected research and eradication efforts, for better or worse?

“Surveillance efforts, outreach, and field and lab work had to be suspended during lockdown. Although we are now able to commence our research, we missed the tail end of the summer 2020 field work and there are also a few organisations who have had to reassess priorities due to budgetary considerations.”

Conflict of interest statement: Mahajabeen Padamsee is Programme Leader for Beyond Myrtle Rust.

Dr Patrick Cahill, Marine Biosecurity – Team Leader, Cawthron Institute, comments:

What does the future look like for marine biosecurity efforts?

“As an isolated island nation, New Zealand is ideally positioned to develop and implement biosecurity systems that actually work. Marine biosecurity has long been the ‘poor cousin’ of its terrestrial counterpart, but there is rapidly growing awareness of the threats posed by marine invaders. Invasive pests and diseases can alter near shore ecosystems, degrade cultural values, and present omnipresent threats to aquaculture and wild fisheries. There is clearly much at stake.

“A common theme in marine biosecurity has been the extreme difficulty of eradicating invaders once they have established. The old adage that ‘an ounce of prevention is worth a pound of cure’ holds true, and our best chances are to proactively prevent invaders arriving in the first place or to rapidly respond and snuff them out before they gain a foothold. In line with this thinking, New Zealand is leading the world with the first national level biofouling regulations in the form of ‘Craft Risk Management Standard for Vessel Biofouling’. Biofouling – a generic term for the myriad of sea life that grows attached to surfaces – facilitates species movements on a global scale and, along with ballast water, has been responsible for most marine invasions. By ensuring ships, yachts, and other maritime vessels arrive in New Zealand free from biofouling, we will greatly reduce the influx of marine invaders.

“But, as with any emerging system, a range of tools and systems need to be developed to support successful implementation now and in the future. Operating in the marine environment is technically difficult due, in large part, to the simple fact that we cannot easily see or access below the sea surface. There is extensive research effort in New Zealand and overseas to overcome the inherent challenges, and in doing so develop fit-for-purpose biosecurity risk prediction, monitoring, and management tools. Cawthron is playing a significant role in these collaborative efforts via our MBIE-funded research programmes, Sustainable Science Investment for aquaculture, and operational research for government and industry.

“Developing and adapting the latest advances in technology and automation shows particular promise for the future. Eco-friendly surface coatings and treatments are being developed to prevent biofouling on ships and other marine infrastructure effectively and safely. Molecular methods to detect ‘DNA signatures’ of invaders in the environment offer orders of magnitudes improvements in detection efficiency and cost, and autonomous underwater vehicles are being equipped with image recognition capability for automated surveillance of vessels and high-risk sites. Sophisticated pathway models are allowing accurate prediction of biosecurity risks and outcomes to inform the best management decisions. Operationalising and integrating such cutting-edge tools promises a future where biosecurity practitioners are empowered to implement holistic marine biosecurity systems that are both cost-effective and fail-safe.

“But, effective and convenient tools are only part of the story – biosecurity success ultimately relies on human behaviour. Raising public and industry awareness of the importance of biosecurity is essential, and New Zealand’s ultimate strength lies in engaging and deploying our ‘biosecurity team of 5 million’.”

No conflict of interest.

Dr Graeme Inglis, Manager – Oceans Platform and Marine Biosecurity Programme lead, NIWA, comments:

“Keeping marine pests and diseases out of New Zealand’s coastal environment requires a vigilant surveillance system, robust regulation, and the development of new technologies to help combat the increasing number of invasive species found here in the past 20 years. New Zealand is fortunate to have had an active surveillance programme in our ports for almost two decades that has enabled the detection of numerous pests over that time.

“The number detected continues to rise for several reasons: we have looked more intensively, the volume of shipping into New Zealand – which brings most of these pests and diseases with them in ballast water or biofouling (organisms or small animals the grow on wet surfaces) – has increased, and the size of those vessels has also grown substantially.

“It is mandatory for ships coming to New Zealand to exchange ballast water in the open ocean before they arrive but this is not an infallible system. By 2024 all international vessels that carry ballast water will be required to treat it on-board to an internationally accepted standard before it can be discharged. New Zealand has also introduced measures to reduce the risk from pests arriving in biofouling. In 2018, a Craft Risk Management Standard came into force that requires ships to have clean hulls when they arrive in our waters.

“One of the biggest challenges for successful marine biosecurity is preventing the entry and spread of marine pathogens. Across the world we are seeing the emergence of new disease manifestations sometimes because the environment is changing or because a species has been recently introduced or both.

“Recently, the waterborne parasite Bonamia ostreae was reported for the first time in the Southern Hemisphere in New Zealand flat oysters. Bonamia ostreae is a notifiable parasite to the World Organisation for Animal Health (OIE) because of the severity of disease that it can cause to oysters. Its discovery in New Zealand in 2015 prompted oyster farms to be removed to contain its spread. While the exact origin of Bonamia ostreae in New Zealand is not known, examination of its DNA suggests strongly that it came from overseas relatively recently.

“Advances in DNA technologies are greatly improving our ability to diagnose new pests and diseases and to detect and monitor them in natural environments (as environmental DNA; ‘eDNA’). Several other technological advances are also a welcome addition to our marine biosecurity efforts. The use of underwater remotely operated vehicles (ROV) assists us in places where it is too dangerous to deploy divers, such as busy ferry terminals or where there is dangerous wildlife present.

“The ROVs produce really high-quality imagery – particularly useful in turbid environments – and we also have the potential to automate the analysis of it which would be a fantastic tool.

“NIWA is also researching how the sounds produced by marine pests might be used to detect or control them. This technique is used in terrestrial biosecurity measures for pest insects and animals and we know that sound also travels very well in the marine environment.”

Conflict of interest statement: NIWA provides operational services in marine biosecurity surveillance and response under contract to Biosecurity NZ. This includes delivery of the national Marine High Risk Site Surveillance and Marine Invasives Taxonomic Service.

Dr Deborah Hofstra, Freshwater ecologist, NIWA, comments:

“Many of New Zealand’s freshwater habitats have been invaded by organisms not native to this country. We know that more than 200 species of freshwater animals and plants have naturalised in New Zealand, the vast majority introduced as ornamental garden pond or aquarium specimens and later disposed of or deliberately released into water bodies.

“The impacts can be significant, including destabilisation of aquatic environments, loss of indigenous plant biodiversity, implications for human health and cultural wellbeing, economic losses through lost hydropower generation, impeded drainage and irrigation and reduced opportunities for recreational activities like boating and fishing.

“NIWA has recently completed the Freshwater Pests of NZ publication showcasing invasive species that we need to be on the lookout for.

“However, the priority isn’t just knowing what to look for, it’s knowing how to look and where to look. This may sound obvious, but the challenge with the aquatic environment is that invasive species may not be noticed until they are already established, and people see an issue at the surface of the water.

“This can mean that pest numbers are already high, making it harder to get rid of them. That’s why we need the right biosecurity tools to monitor for invasive species.

“Our research priorities in this field include being better at detecting pests at an early stage of invasion. While we carry out a lot of diving and monitoring programmes, new technology and the development of new methods is a high priority and is evolving rapidly. NIWA’s research using hydroacoustic, underwater imagery and an autonomous boat for detection is a great example of this.

“Imagine if we could send a remote-controlled vehicle along a lake shoreline scanning for invasive species, sending the data back for hydroacoustic/image recognition, rather than people having to make observations underwater at multiple sites.

“We also have the capacity to collect more data than previously, but we want to achieve more with that data, and machine learning is an important part of the science. A good example is the difference between being able to detect whole weedbeds of an invasive species, when the goal is to detect a single shoot at an early stage of invasion. Early detection is critical as it enables a rapid response.

“Another challenge is changing infrastructure, in particular the risk posed by connections between water delivery and storage systems. These increase the pathways for freshwater pests to move around.

“And climate change is also a concern. Rising temperatures and carbon also come with significant consequences for biosecurity. Freshwater biosecurity is about responding at some level (from informing legislation to actions on the ground) to the biological threats to our aquatic ecosystems.

“In general, species that are designated as pests or invasive are often characterised by their ability to survive and thrive over a wide range of environmental tolerances. These ‘invasive’ characteristics are also likely to mean pest species are well suited to range expansion under predicted climate change scenarios.”

No conflict of interest.