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The Department of Pest Management and Conservation carries out research and teaching in the following specialist areas: Animal behavior; Conservation and biodiversity; Ecological restoration; Evolutionary biology; Fire ecology; Molecular ecology; Plant microbiology; Plant pathology; Remediation of degraded and contaminated land; Soil ecology; Sustainable agriculture and ecosystem services; Wildlife and pest management.
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Recent Submissions
Item Open Access Predator-Free New Zealand 2050: Techniques for improving ground based control and monitoring of the brushtail possum(University of California, 2024-08-30) Ross, James; Graham, B; Pitt, K; Timm, RM; Woods, DMThe brushtail possum, a marsupial native to Australia, was widely introduced in New Zealand (NZ) to develop a fur industry. Before the settlement of humans in NZ, there were no terrestrial mammals; therefore, the local species evolved without mammalian predators. This resulted in native species populations declining at alarming rates and many possibly facing extinction on the NZ mainland, especially large-bodied endemic birds. In response to this problem, private investors (supported by the NZ government) developed an initiative to eradicate key mammal predators (possums, rats, and stoats) on the NZ mainland by 2050 (PFNZ2050). As a result, control efforts have significantly expanded over the past decade, and there are now 17 PFNZ2050 landscape projects covering 757,000 ha. Research has looked at combining audio, visual and social lures to improve control efforts for possums. Early results indicate that a combination of lures increases both encounter and interaction rates around control devices. In particular, the combination of audio and visual lures was consistently the top performer in both captive and small-scale field trials. Large-scale field trials are currently underway to confirm these initial results, investigating the effectiveness of combination lures paired with multi-kill AT220 possum traps. Additionally, the lures are being assessed at different times of the year and with varying possum densities. With the drive to PFNZ2050, pest mammal monitoring has markedly competing management control strategies. Traditionally, this has relied on single-use plastic monitoring devices such as chewcards and tracking tunnels. An investigation of pest-animal interaction with chewcards indicates that approximately 12% of plastic deployed ends up as microplastic pollution. Another NZ government initiative seeks to ban all single-use plastics, and research is currently investigating the efficacy of non-plastic (biodegradable) alternatives. This research also includes a cost-effectiveness analysis and the reliability of identifying animal bite marks on both plastic and non-plastic chewcards.Publication Open Access Estimating diet of the European hedgehog (Erinaceus europaeus) using molecular analysis of faeces and colon content : A thesis submitted in partial fulfilment of the requirements for the Degree of Master of Science at Lincoln University(Lincoln University, 2024) Walker, MaryanneNew Zealand has a unique ecosystem that evolved without the presence of mammalian predators. Since human colonisation, several species of mammalian predators have been introduced, including the European hedgehog (Erinaceus europaeus). The hedgehog, in its native range, mainly feeds on invertebrates, with minor dietary components of bird eggs and lizards. I used molecular methods to analyse the diet of hedgehog in New Zealand. Molecular methods have an important advantage over the traditional visual analysis of faeces and stomach contents as they allow for better identification of soft-bodied remnants of prey items. I successfully used species-specific primers to detect a known species (mealworms, Tenebrio molitor) in hedgehog faeces after a controlled feeding trial. Next, I trialled a simple visualisation method to compare the quality of DNA extracted from hedgehog stomach and colon contents. Unfortunately, the visualisation method trialled did not determine any differences in the DNA quality of the two sample sources and further trials are required. I created a local reference database of invertebrates collected from pitfall trapping at Kaitorete Spit. Barcode sequences developed for the local reference library were uploaded to BOLD systems to contribute to the growing global database of sequences. This local reference database successfully enhanced the taxonomic rank assignment of amplicon sequence variations produced during metabarcoding. I used high throughput sequencing on faecal and colon samples. Several taxa from the phyla Arthropoda, Annelida, Mollusca, Nematoda, and Rotifera were identified and reported at the genus and family (for Arthropoda) taxonomic level. There was a considerable level of taxon heterogeneity in the prey items not between samples. High abundances of Arthropoda were identified in colon samples, while faecal samples had higher abundances of all other phyla. The results from this study are consistent with earlier morphological studies of hedgehog diets in New Zealand and Europe but add greater detail. The dietary results from this study are important and applicable in both New Zealand and worldwide. For New Zealand, this study contributes to understanding the ecological impacts that hedgehogs have in New Zealand while providing justification for ongoing monitoring plans that control hedgehogs to prevent detrimental impacts. Worldwide, these methods can be used, especially in the hedgehog’s natural habitat, to understand their natural diet to assist with conservation where this species is endangered. Future studies should expand the area studied to explore dietary variation across a spatial scale and where other endangered species are at risk from hedgehog predation.Item Open Access Metabolomics for plant health biosecurity diagnostics and response(MDPI, 2023-03) Ross, AB; Muller, H; Subbaraj, A; Homewood, I; Mas, F; Hardwick, S; Stringer, L; Vereijssen, J; Visnovsky, S; Najar-Rodriguez, A; Armstrong, KarenThe increasing diversity of potential biosecurity threats makes their diagnosis a complicated and evolving area, requiring moving beyond traditional taxonomic species identification. New biosecurity diagnostic tools should provide a greater depth of information on threat biology to enable accurate risk assessment for the more efficient and effective deployment of biosecurity resources. Metabolomics is amongst the new approaches being explored for biosecurity diagnostics, where a broad spectrum of metabolites might signify relevant biological characteristics of an intercepted organism. Examples of these characteristics are physiological signatures of age, reproductive status, geographic origin, pathogen status of potential invertebrate vectors, and the distinction between diseases and abiotic plant stress symptoms. This broad-based approach is attractive, where several biological characteristics of an organism can be assessed with a single measurement. However, it can be impractical as several hundred biological replicates of the organism are needed to build a robust model of a species. New approaches such as mass spectral fingerprinting substantially reduce the time taken for metabolomics measurements, and more sophisticated modelling methods aid feasibility. Promising data are emerging for metabolomics and metabolite fingerprinting for potential biosecurity applications. We discuss the possibilities and potential uses for these new tools for post-detection decisions, diagnosis, and biosecurity.Publication Restricted Bait preferences in rabbits (Oryctolagus cuniculus) and non-target species in rabbit-prone areas of New Zealand’s South Island : A thesis submitted in partial fulfilment of the requirements for the Degree of Master of Science at Lincoln University(Lincoln University, 2024) Meban, AnnaRabbits (Oryctolagus cuniculus) are an introduced pest species that plagues New Zealand’s dryland and semi-arid environments. They are particularly abundant in areas of the South Island, including the Mackenzie Basin and Central Otago region. The current best practice for rabbit control is aerial distribution of carrot and cereal baits laced with pindone or 1080. Carrot tends to be the most preferred bait type; however, it poses issues in terms of its quick deterioration in field settings, as well as being costly and time-consuming to produce. With pest control in New Zealand focusing on eliminating predator-free species, there are large gaps in knowledge surrounding the development of more effective rabbit control tools, as well as the monitoring of non-target species present in rabbit settings. I conducted bait palatability trials, testing several novel and current baits to determine preferences in both rabbits and non-target species. An initial trial was run at Mt. Grand Station (Lake Hawea) in August 2023, testing four different bait types (fresh carrot, carrot jam, carrot oil mayonnaise (mayo) and RS5 non-toxic cereal pellets). Bait types were rotated through covered and uncovered bait stations. A further trial was run at Lilybank Station (Lake Tekapo) in October 2023, testing four bait types (fresh carrot, carrot jam, and two new cereal pellets A & B (formulated by Kiwicare), without using the covered bait stations. Interactions with all bait types were low. The bait types most interacted with by rabbits were fresh carrot and carrot jam. Visits were much more abundant than interactions. Rabbits visited carrot the most at Mt. Grand and cereal pellets B at Lilybank. Despite little consumption of bait types, they were still successful at luring individual rabbits to a site. Many non-target species were present in these rabbit environments. At Mt. Grand, blackbirds were the species that had the most interactions overall, mostly with carrot jam. At Lilybank, possums were the non-target that showed the most interactions, with the preferred bait type also being carrot jam. There was some neophobia toward covered bait stations, with visits at Mt. Grand decreasing as time went on, and interaction levels staying consistently low until the bait was placed outside the covered bait stations. At Lilybank (where covered bait stations were not used), there was a small increase in both visits and interactions over time. Activity data suggested that rabbits are most active around the sunset period and during the night. Further testing of novel bait without covered bait stations is required to better understand bait preferences without the effects of neophobia. The results produced by this study suggest that carrot jam or a bait type with high carrot content, should be successful at initiating pest rabbit interactions. However, further development and refinement is required to mitigate the risk associated with non-target species.Item Open Access Uncovering the multifaceted properties of 6-pentyl-alpha-pyrone for control of plant pathogens(Frontiers Media S.A., 2024-06-18) Mendoza - Mendoza, Artemio; Esquivel-Naranjo, EU; Soth, S; Whelan, Helen; Alizadeh, Hossein; Echaide-Aquino, JF; Kandula, D; Hampton, JohnSome volatile organic compounds (VOCs) produced by microorganisms have the ability to inhibit the growth and development of plant pathogens, induce the activation of plant defenses, and promote plant growth. Among them, 6-pentyl-alpha-pyrone (6-PP), a ketone produced by Trichoderma fungi, has emerged as a focal point of interest. 6-PP has been isolated and characterized from thirteen Trichoderma species and is the main VOC produced, often accounting for >50% of the total VOCs emitted. This review examines abiotic and biotic interactions regulating the production of 6-PP by Trichoderma, and the known effects of 6-PP on plant pathogens through direct and indirect mechanisms including induced systemic resistance. While there are many reports of 6-PP activity against plant pathogens, the vast majority have been from laboratory studies involving only 6-PP and the pathogen, rather than glasshouse or field studies including a host plant in the system. Biopesticides based on 6-PP may well provide an eco-friendly, sustainable management tool for future agricultural production. However, before this can happen, challenges including demonstrating disease control efficacy in the field, developing efficient delivery systems, and determining cost-effective application rates must be overcome before 6-PP’s potential for pathogen control can be turned into reality.Publication Embargo Assessing the prevalence, diversity, and damage potential of plant-parasitic nematodes on maize (Zea mays L.) : A thesis submitted in partial fulfilment of the requirements for the Degree of Doctor of Philosophy at Lincoln University(Lincoln University, 2024) Nagarathnam, ThiruchchelvanMaize cultivation faces challenges from plant-parasitic nematodes (PPNs), which can significantly reduce yields. Despite their importance, PPNs are often underestimated in agricultural ecosystems. Research in New Zealand and Sri Lanka reported the presence of PPNs in maize fields. However, comprehensive data is still lacking. Environmental factors such as soil pH, moisture content, nutrient levels, and rainfall could influence PPN population densities and pathogenicity. Hence, understanding PPN dynamics and environmental interactions is crucial for sustainable production. This study aimed to; i) examine the prevalence, abundance, and distribution of PPNs associated with maize cultivation in Sri Lanka and New Zealand, ii) identify the most abundant PPN species and their distribution in New Zealand maize fields, iii) investigate the relationship between soil edaphic and climatic characteristics with PPN abundance in New Zealand maize fields, and iv) screen the susceptibility of commercially available maize hybrids in New Zealand against the most abundant PPN genus under glasshouse conditions. A survey conducted in Sri Lanka's semi-arid regions with major maize cultivation areas found that over 92% of maize fields tested positive for PPNs. The dominant species was Pratylenchus spp., with a mean population density of 2020 kg-1 of soil. Sampling at different maize growth stages revealed that Pratylenchus spp. populations were below 1000 kg-1 of soil at the seedling stage but increased by 2 to 10-fold at harvest. In New Zealand, a total of 384 soil samples were collected from 25 sites from both the North (NI) and South Island (SI) of New Zealand from maize growing regions. The major PPNs identified by morphology were Pratylenchus (91%), Helicotylenchus (38%), Meloidogyne (14%), Tylenchus (14%), Heterodera (8%), Paratylenchus (3%), and Criconemella (1%). Pratylenchus spp. were widespread across all surveyed regions. In most sampled sites from both islands, Pratylenchus spp. exceeded 1000 kg-1 of soil, which is recognised as the economic threshold set by nematologists worldwide. Five Pratylenchus spp. in New Zealand maize fields: P. crenatus, P. neglectus, P. thornei, P. penetrans, and P. pratensis, were identified based on morphology and the sequencing of DNA-PCR products extracted from single nematode using Sanger sequencing. Among these, P. crenatus and P. neglectus were predominant across maize-growing regions in New Zealand. The soil analysis revealed that tested soil properties varied between the sampled regions, while PPN abundance and diversity exhibited a regional dissimilarity. The relationship between PPN composition and soil physicochemical properties of New Zealand maize fields analysed using the canonical correspondence analysis (CCA). Results showed that soil moisture, pH, soil P, and percentages of sand, clay, N, and C significantly influenced PPN abundance and distribution. However, the influence of soil parameters on the PPN population varied within the regions, where soil moisture content was the main driver for the PPN population abundance within all three regions. A year-round sampling conducted at one of the sites in the Canterbury region of SI revealed the influence of seasonal and cropping factors on PPN abundance. This indicated a 5-fold population increase of Pratylenchus spp. from crop establishment to maturity during a season. Also, CCA on seasonal variations on soil physicochemical, climatic factors, and PPN population abundance in a field revealed that the soil moisture, volumetric water content, bulk density, sand%, N and C with the climatic factors; rainfall, relative humidity, and sunshine hours had a significant relationship with PPN population dynamics. Three nematode extraction methods for maize roots were tested. Centrifugal sugar flotation yielded the highest nematode count but with low clarity for microscopic observation. The Baermann funnel had 35.9% extraction efficiency with high clarity. The Whitehead tray had 60.8% efficiency with moderate clarity compared to centrifugal sugar flotation. The Whitehead tray is a good compromise for clarity and count, while sugar flotation is efficient and faster processing of samples for Pratylenchus nematodes, adding another layer of information for future studies. The outcomes from the glasshouse experiments using 15 commercial maize hybrids and a mixed field population of Pratylenchus spp. showed that most tested maize hybrids were susceptible to Pratylenchus spp. and demonstrated varying degrees of susceptibility. Another glasshouse experiment was conducted to determine the pathogenicity and reproduction of Pratylenchus on three selected maize hybrids based on the results from the previous trials. The results demonstrated significant reductions in root dry weight across hybrids, with losses ranging from 33% to 42%, and shoot weight losses varied among hybrids 10 to 22% compared to the controls 60 days after planting. This is the first comprehensive study on the PPN community association with maize in Sri Lanka and New Zealand. These findings emphasised the potential impact of PPNs, particularly Pratylenchus spp., on maize yield in both countries, highlighting the urgent need for further research to develop effective PPN management tactics adapted to local conditions.Item Open Access Root-lesion nematode (Pratylenchus spp.) extraction from maize roots: A comparison of three methods(New Zealand Plant Protection Society (Inc.), 2024) Nagarathnam, T; Casonato, Seona; Moukarzel, Romy; Condron, L; Kularathna, ManjulaThis study examines differences in extraction efficiency of three methods for extracting root-lesion nematodes (Pratylenchus spp.) from maize roots. The Baermann funnel, Whitehead & Hemming tray, and centrifugal-sugar flotation methods were evaluated for efficiency and clarity using microscopic observation. Statistical analysis confirmed significant differences among the methods. The centrifugal-sugar flotation method yielded the highest nematode count (1874±76 per 5 g of roots) but the clarity of the observation field under the microscope was lower due to root residues compared to the other two tested methods. The Baermann funnel method yielded 35.9% extraction efficiency (672±46 per 5 g of roots) compared to the centrifugal-sugar flotation method with higher clarity of the observation field than other tested methods. The Whitehead & Hemming tray presented a moderate level of observation field clarity compared to other tested methods with a nematode extraction efficiency of 60.8% (1140±53 per 5 g of roots) compared to the centrifugal-sugar flotation method. The results suggest that the Whitehead & Hemming tray could be a viable choice for nematode extraction, especially when both nematode numbers and microscopic clarity are important considerations. Understanding the restrictions of each methodology enhances the accuracy of nematode quantification leading to improved and updated data for maize producers in New Zealand.Item Open Access Puke or poop? Comparison of regurgitate and faecal samples to infer alpine grasshopper (Paprides nitidus Hutton) diet in experimental plant communities(Wiley-Blackwell, 2023-08) Allen, WJ; Waller, Lauren; Barratt, BIP; Dickie, IACharacterising plant-herbivore interactions is important to understanding the processes that influence community structure and ecosystem functioning. Traditional methods used to identify plant-herbivore interactions are being superseded by non-destructive molecular approaches that can infer interactions with greater resolution and accuracy from environmental DNA (e.g. faeces and regurgitate). However, few studies have compared the success of using different sample types and whether they provide similar or contrasting information about species' diet. Here we compared the success of DNA amplification and host plant species identification using restriction fragment length polymorphism (RFLP) applied to faecal and regurgitate samples collected from alpine grasshoppers Paprides nitidus Hutton during a grassland community mesocosm experiment. We found that DNA amplification success was 23% and 86% higher for faecal than regurgitate samples from female and male grasshoppers, respectively. In contrast, successful host plant identification using RFLP was 9% higher for regurgitate than faecal samples. The mean number of host plant species identified per sample (1.40) did not differ between sample types or grasshopper sexes. Of the 136 paired faecal-regurgitate samples, just 41% and 74% produced exactly or partially matching host plant identifications, respectively, indicating that different sample types provided complementary information about herbivore diet. Some plant species were more likely to be identified from faecal samples than expected by chance, and we found that this identification bias skewed towards plant species with higher investment in leaf tissue. We conclude that multiple sample types may be required to fully characterise an invertebrate herbivore species' diet.Item Open Access High maintenance of rhizosphere soil C and N equilibrium regardless of plant species or species traits(Frontiers Media S.A., 2021-10) Wakelin, SA; Matson, A; Wigley, K; Waller, L; Dickie, IA; Whitehead, D; Garrett, LFactors affecting the deposition of carbon and nitrogen into the rhizosphere soil have important implications for natural and managed ecosystems. These include the invasiveness of plants, extent to which ecosystems sequester soil carbon, through to regulation of N flow within and from agricultural ecosystems. This study determined if the close elemental ratios often measured in soils are evident within the highly active rhizosphere compartment, or rather potentially emerge to a conserved ratio (over time) from different initial rhizosphere states. Toward this, we assessed the rhizosphere C and N content (and C:N ratio) of 37 plant species; these were further grouped into the categories provenance (native or exotic to New Zealand), form (forb, grass, shrub, or tree), root-based nitrogen fixation symbiosis (+/– N-fixation), or mycorrhization type. Furthermore, the potential nitrification rate (PNR) among the plant rhizosphere soils was quantified to explore relationships between nitrate formation and the total C and C:N ratio. Mycorrhization status, provenance, and form had no significant influence on nutrient status nor PNR in rhizosphere soil samples (p > 0.05). However, total C and total N were significantly increased in the rhizosphere of N-fixing species (p < 0.02). These increased in proportion, with the C:N remaining constant for both groups (∼12.24; p = 0.79). Rhizosphere PNR did not vary with categories of plants tested and had no correlation to rhizosphere total C, total N, nor C:N ratio (p > 0.3 for all). Overall, this study showed that conservation of nutrient ratios often measured in soils are present within the rhizosphere, where initial inputs of C and N enter the soil ecosystems. With the exception of N-fixing plant species, rhizosphere soils retain remarkably high conservation in C, N, C:P, and PNR among key groupings.Publication Open Access An investigation of systematic camera trap monitoring for kiwi (Apteryx spp.) : A thesis submitted in partial fulfillment of the requirements for the Degree of Doctor of Philosophy at Lincoln University(Lincoln University, 2023) Tansell, A Jane SIntroduction: Kiwi (Apteryx spp.) are one of New Zealand’s national taonga/taoka (treasures) that are our responsibility and privilege to protect. To inform protective management, we need to monitor kiwi population responses to management, for which a non-invasive method that can detect all age classes has been lacking. Camera traps are non-invasive monitoring devices, which are increasingly used with recently developed analyses to monitor cryptic terrestrial species around the world. To apply these methods to kiwi, standardized methods need to be developed and benchmarked against existing methods. Aims: The aims of this study were to 1) summarise previous monitoring work on kiwi to develop a draft systematic camera trap monitoring method for kiwi, 2) determine optimal site selection and camera trap set-up, 3) determine optimal survey length and camera trap spacing for use with spatial presence-absence (SPA) analysis and identify whether realistic population estimates are obtained, 4) compare camera traps with a current noninvasive method using acoustic recorders to determine if they give realistic and comparable estimates when used with SPA, 5) compare camera traps with dog survey and an observer listening survey to assess kiwi population health, 6) trial alternative analyses for use with camera traps in high density sites, 7) investigate stereo cameras for their potential to add value to camera trap surveys. Materials and methods: We summarised the current literature on monitoring kiwi and the use of camera trap surveys. We deployed 34 camera traps over six seasons in Orokonui Ecosanctuary. We deployed 29 acoustic recorders and carried out detector dog surveys to compare the number of juveniles detected. We deployed 17 camera traps in Rotokare Scenic Reserve and 18 camera traps in the Cape Sanctuary to examine their effectiveness in high kiwi density areas. We constructed a stereo camera by chaining two off-the-shelf trail cameras together to trigger from one PIR sensor and briefly trialled the stereo camera at Orokonui. Results: Cameras were able to detect kiwi of all age groups and to provide credible population densities and trends. Kiwi detections can be maximised by using a detector dog team to select camera sites and through camera orientation. Comparable population estimates were obtained using spatial presence-absence (SPA) analysis with an optimal survey length of four months, during peak incubation, and optimal camera spacing of 350 m. Cameras and acoustic recorders gave comparable population estimates using SPA. Estimates were realistic based on matrix population model projection. Camera traps and detector dog surveys found a similar number of juvenile kiwi. Estimates obtained using Royle-Nichols analysis likely underestimated population size but correctly indicated population trend direction and magnitude, while the index-manipuation-index method did not give a biologically possible estimate of population density. The stereo camera method using two trail cameras was capable of giving surprisingly accurate bill measurements, but further work in necessary to achieve repeatability. Discussion and conclusions: Systematic camera trapping is capable of monitoring the whole kiwi population, including female and young kiwi that are usually under-recorded by other methods. Systematic camera trapping paired with spatial presence-absence analysis performed well in a low density population. Camera monitoring shows much promise as another useful noninvasive tool in the kiwi monitoring toolbox.Publication Unknown Evaluating the in vitro efficacy of Abamectin and Fluopyram, alongside hot water treatments against Meloidogyne incognita and Globodera rostochiensis : A thesis submitted in partial fulfilment of the requirements for the Degree of Master of Applied Science at Lincoln University(Lincoln University, 2023) McDonald, MarissaPlant germplasm importation into Aotearoa/New Zealand poses a risk of introducing unwanted organisms. Current biosecurity measures for plant nematodes on imported nursery stock are under review. This study aimed to investigate alternative chemicals that could replace fenamiphos, the current border treatment. Abamectin and fluopyram were chosen for assays based on their demonstrated nematocidal activity and availablity. Hot water submersion was also tested as a non- chemical alternative. Pratylenchus sp. were extracted from field samples and identified using morphology and molecular methods. Cultures of Meloidogyne incognita and extraction of Globodera rostochiensis cysts were successful, but Pratylenchus sp. cultures could not be established. Preliminary experiments tested the field rates of abamectin (0.009 g/L a.i) and fluopyram (0.3 g/L a.i.) individually and in combination, along with two fenamiphos concentrations (2 g/L and 40 g/L). Abamectin and fluopyram resulted in paralysis rates of ≥ 66.7% in M. incognita J2s, while fenamiphos exhibited no significant differences from the negative control. All treatments produced reversible effects on J2 immobility, indicating a nematistatic effect. Hot water experiments at 44°C for 3 hours caused complete and irreversible paralysis in M. incognita J2s. Further experiments using varying concentrations of abamectin and fluopyram on M. incognita J2s, indicating the highest paralysis rate with abamectin (0.09 g/L a.i.) was 75.2%, while concentrations of fluopyram ≥ 0.6 g/L resulted in 100% paralysis. All combined concentrations of abamectin and fluopyram resulted in 100% paralysis, as did hot water treatments for 1 and 2 hours at 44 and 50°C. In preliminary experiments, no chemical treatments achieved complete mortality in G. rostochiensis juveniles, and no significant differences were observed in the proportion of immobile juveniles compared to the negative control. Hot water treatments at 44°C for 3 hours, in combination with abamectin, fluopyram, abamectin and fluopyram together, and 40 g/L fenamiphos, completely immobilized G. rostochiensis juveniles 48 hours after treatment. Retrospective analysis found the G. rostochiensis experiment results inconclusive due to assessing viability based on movement rather than more precise methods. A preliminary trial using Meldola blue stain revealed that live G. rostochiensis juveniles remained unstained, while dead juveniles stained when exposed to 0.05% Meldola blue for 3, 5, and 7 days. This method was incorporated into further G. rostochiensis experiments. Further chemical experiments on cysts showed no differences compared to the negative control of RO water based on the proportions of juveniles stained with Meldola blue. Hot water treatments at 44°C and 50°C for 1 and 2 hours caused a lower percentage of deceased juveniles compared with the negative control of 24°C. Further experimentation using in planta bioassays are recommended to assess how the chemicals affects nematodes contained within plant tissues as well as plant viability. Expanding the research to encompass a broader range of nematode species is also recommended. Overall, the study demonstrated the potential of abamectin, fluopyram and hot water submersion which provided the complete mortality required in biosecurity situations as alternatives to fenamiphos for biosecurity measures in Aotearoa/New Zealand.Publication Unknown AI feedback loops in Aotearoa New Zealand: A Human-centered creative problem-solving approach(Center for Open Science, 2024-05-10) Agyepong, V; Cattoen, C; Adusei-Fosu, K; Buelow, FA; Wilson, TK; Qasim, M; Grimshaw, GM; Godsoe, WArtificial Intelligence (AI) can have unintended consequences in systems where they are deployed. Researchers have found that by increasing contextual understanding of AI feedback loops, cause and effect in systems, especially in high-risk applications like health, biosecurity, conservation, justice systems, and transport, AI tools can learn to improve over time and leverage wider neural networks. This paper fills the knowledge gap on how to consider varying competencies of human-AI teams to identify feedback in AI systems leveraging eight disciplines outside commerce and computer science. The study found that academic actors from more than one discipline tend to identify more relevant sources of feedback in AI systems, especially in high-risk applications. The paper recommends the integration of human lived experiences, knowledge generated from partial exposure of academic ideas to non-academic actors, and knowledge of decision making in the natural environment to reduce the incidence of misinformed human decision-making, especially in high-risk applications.Publication Unknown Summary for Policymakers of the Thematic Assessment Report on Invasive Alien Species and their Control of the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services(IPBES, 2023-09-04) Roy, HE; Pauchard, A; Stoett, P; Renard Truong, T; Bacher, S; Galil, BS; Hulme, Philip; Ikeda, T; Sankaran, KV; McGeoch, M; Meyerson, LA; Nunez, M; Ordonez, A; Rahlao, SJ; Schwindt, E; Seebens, H; Sheppard, AW; Vandvik, V; Piero, G; Wilson, JRThe thematic Assessment of Invasive Alien Species and their Control, or “Invasive Alien Species Assessment” in short, is part of a series of reports whose production was initiated during the “first work programme of IPBES, 2014 2018” and concluded during the current “IPBES rolling work programme up to 2030”. The Invasive Alien Species Assessment has been carried out by a multidisciplinary team of 86 selected experts from all regions of the world, including early career fellows, assisted by about 200 contributing authors. More than 13,000 scientific publications were analyzed as well as a substantive body of Indigenous and local knowledge. Its chapters were accepted, and its summary for policymakers was approved, by the IPBES Plenary composed of 143 member States at its tenth session held from 28th August to 2nd September 2023 in Bonn, Germany. The Invasive Alien Species Assessment builds on the landmark IPBES Global Assessment Report on Biodiversity and Ecosystem Services launched in 2019. The Global Assessment identified invasive alien species as a one of the five main direct drivers of biodiversity loss, with 1 million species of plants and animals now at risk of extinction. The Invasive Alien Species Assessment explores how invasive alien species affect nature and people globally. It analyzes the status and trends of alien and invasive alien species in all regions of Earth, and identifies major pathways for and drivers of the introduction and spread of such species between and within countries. The Assessment also assesses the effectiveness of management actions across scales and in various contexts. The Invasive Alien Species Assessment finally outlines key responses and policy options for the prevention, early detection, and effective control of invasive alien species and mitigation of their impacts in order to safeguard nature, nature’s contributions to people and good quality of life.Publication Open Access Survival of Escherichia coli in edible land snails: Implications for heliciculture and public health(Multidisciplinary Digital Publishing Institute (MDPI), 2024-03) Tanyitiku, MN; Nicholas, G; Sullivan, Jon; Petcheu, ICN; On, StephenBackground: Land snails are considered a delicacy in many countries in Europe and sub-Saharan Africa. However, the interaction of microbial pathogens with land snails may present a public health threat when handling and/or consuming snails. This study examines the survival of Escherichia coli in edible land snails in a model system. Methods: Well-studied Shigatoxigenic (STEC) and non-STEC strains were compared. Mature Helix spp. were experimentally fed with E. coli-inoculated oats for 48 h. The snail feces after inoculation were periodically sampled and cultured for a 30-day period and subjected to microbiological analyses. Results: The average rate of decline of the non-STEC strain CSH-62 in the feces of live snails was significantly (p < 0.05) faster than that of STEC ERL 06-2503. In addition, the viable population of E. coli ERL 06-2503 significantly (p < 0.05) persisted for a longer time in the intestine of land snails than E. coli CSH-62. Conclusion: The results showed that the viable population of the E. coli strains examined demonstrated first-order kinetics, and their survival (CFU/mL) appeared significantly (p < 0.05) dependent on the E. coli pathotype. In addition, the continuous enumeration of E. coli in snail faeces indicated that land snails could serve as a mode of transmission of microbial pathogens to susceptible hosts, including humans. Further research is recommended to better quantify the direct and indirect health risks of pathogen transmission by edible snails to humans.Publication Open Access Turning up the heat: Climate change consequences for Pinot Noir berry quality(Winetitles, 2024-04) Moukarzel, Romy; Parker, Amber; Schelezki, Olaf; Gregan, S; Jordan, BTemperature increase due to climate change affects grapevine productivity and berry quality. Studies have shown that higher temperatures lead to increased sugar concentrations at harvest, or earlier harvests to retain the same sugar targets. Temperature increases may also impact anthocyanins (colour) and amino acids crucial for fermentation. New Zealand researchers out to explore how microclimates influence anthocyanin, phenolic compounds and amino acids in Pinot Noir.Publication Open Access Osmotic stress responses, cell wall integrity, and conidiation are regulated by a histidine kinase sensor in Trichoderma atroviride(MDPI, 2023-09) Calcáneo-Hernández, G; Landeros-Jaime, F; Cervantes-Chávez, JA; Mendoza - Mendoza, Artemio; Esquivel, ETrichoderma atroviride responds to various environmental stressors through the mitogen-activated protein kinase (MAPK) Tmk3 and MAPK-kinase Pbs2 signaling pathways. In fungi, orthologues to Tmk3 are regulated by a histidine kinase (HK) sensor. However, the role of T. atroviride HKs remains unknown. In this regard, the function of the T. atroviride HK Nik1 was analyzed in response to stressors regulated by Tmk3. The growth of the Δnik1 mutant strains was compromised under hyperosmotic stress; mycelia were less resistant to lysing enzymes than the WT strain, while conidia of Δnik1 were more sensitive to Congo red; however, ∆pbs2 and ∆tmk3 strains showed a more drastic defect in cell wall stability. Light-regulated blu1 and grg2 gene expression was induced upon an osmotic shock through Pbs2-Tmk3 but was independent of Nik1. The encoding chitin synthases chs1 and chs2 genes were downregulated after an osmotic shock in the WT, but chs1 and chs3 expression were enhanced in ∆nik1, ∆pbs2, and ∆tmk3. The vegetative growth and conidiation by light decreased in ∆nik1, although Nik1 was unrequired to activate the light-responsive genes by Tmk3. Altogether, Nik1 regulates responses related to the Pbs2-Tmk3 pathway and suggests the participation of additional HKs to respond to stress.Publication Open Access Citizen science is a vital partnership for invasive alien species management and research(Elsevier on behalf of Cell Press, 2024-01-19) Pocock, MJO; Adriaens, T; Bertolino, S; Eschen, R; Essl, F; Hulme, Philip; Jeschke, JM; Roy, HE; Teixeira, H; de Groot, MInvasive alien species (IAS) adversely impact biodiversity, ecosystem functions, and socio-economics. Citizen science can be an effective tool for IAS surveillance, management, and research, providing large datasets over wide spatial extents and long time periods, with public participants generating knowledge that supports action. We demonstrate how citizen science has contributed knowledge across the biological invasion process, especially for early detection and distribution mapping. However, we recommend that citizen science could be used more for assessing impacts and evaluating the success of IAS management. Citizen science does have limitations, and we explore solutions to two key challenges: ensuring data accuracy and dealing with uneven spatial coverage of potential recorders (which limits the dataset's “fit for purpose”). Greater co-development of citizen science with public stakeholders will help us better realize its potential across the biological invasion process and across ecosystems globally while meeting the needs of participants, local communities, scientists, and decision-makers.Publication Open Access Evaluating the densities and distribution of root-lesion nematodes (Pratylenchus spp.) in wheat grown in Canterbury, New Zealand(New Zealand Plant Protection Society (Inc.), 2023-05-18) Thiellier, MJ; Kularathna, ManjulaSpecies of root-lesion nematode (Pratylenchus spp.) are associated with significant reductions in wheat yield in wheat-growing regions around the world. Of these, Pratylenchus thornei and P. neglectus are known to cause the highest damage to the Australasian wheat industry. New Zealand is known to produce high wheat yields on a per-hectare basis yet little research has been conducted to date to determine the effects of Pratylenchus spp. on the production of wheat in New Zealand. Therefore, as the first step towards filling this knowledge gap, the current research focused on conducting surveys to determine the population densities and distribution of Pratylenchus spp. in wheat-growing regions in Canterbury, South Island, New Zealand. Surveys were conducted at ten selected sites that were geographically distinct from each other. At six of the ten sites, lesion nematode populations were reported to be above the recorded Australian threshold of 2000 nematodes per kg of soil. In Australia, it’s been recorded that around 50% yield reductions can occur in intolerant wheat varieties when population densities reaches this number. Differences in population density within each location was also observed indicating the uneven distribution of lesion nematodes within a field. Morphological measurements of the nematodes collected from multiple sites during this study confirmed the presence of P. thornei and P. neglectus in Canterbury wheat-producing areas indicating a potential threat to the New Zealand wheat industry by root-lesion nematodes. Further studies need to be conducted to fully understand the situation and to develop management strategies to mitigate threats from nematodes.Publication Open Access Soil carbon, erosion, and the stormflow mobilisation of sediment and nutrients in a high-country landscape : A thesis submitted in partial fulfilment of the requirements for the Degree of Doctor of Philosophy at Lincoln University(Lincoln University, 2023) Provost, Shyam MichaelThis study was carried out at Mt. Grand Station, a high-country pastoral farm in the South Island of New Zealand. The landscape (400 - 1300 m altitude) supports a gradient and mosaic of native and endemic woody shrub and tussock grassland vegetation amongst more productive exotic pasture, the latter established through aerial seed top-dressing and fertilisation. In recent years several areas of the farm at higher altitudes have been converted to conservation management following Tenure Review, placing additional pressure on the remaining farmland to maximise productivity, a situation similarly faced by many other high-country farms. However, further intensification of pasture grassland would compromise existing less productive native vegetation. This research project investigated soil conservation and loss, and freshwater quality, aiming to advance existing knowledge relating to environmental sustainability of the high-country. Topsoil carbon stocks were quantified beneath various vegetation communities at different altitudes of the station to gain a better understanding of soil carbon and its dynamics. Two watershed catchments were targeted for high-frequency sampling during rainfall events, to investigate the likely significance of water flow on the mobilisation of sediment and nutrients, and to help improve the accuracy of existing run-off estimates. In addition, soil erosion was estimated from differences in residual soil 137Cs activity, which was generated from historic Pacific nuclear testing, between two of the dominant types of vegetation cover. The results revealed the potential for native vegetation to enhance soil carbon sequestration. At low - middle altitudes (450 - 850 m) of the farm, topsoil beneath a woody shrub (kānuka) vegetation cover had significantly higher carbon concentrations and carbon stocks than areas of adjacent pasture. At higher elevations (>1000 m) topsoil beneath dominant snow tussocks had significantly higher carbon, nitrogen and phosphorus concentrations, with higher carbon stocks than adjacent inter-tussock spaces. The total loads of suspended solids, nitrogen and phosphorus exported to catchment waterways were significantly larger during high-flow events in comparison to baseflow conditions, and large proportions of the high-flow loads were mobilised on the rising hydrograph following high rainfall. These findings draw attention to the significance of taking account of the early stages of rainfall events to improve accuracy when quantifying high-country catchment loads. Data for 137Cs were variable but these provisional results indicate that soil beneath kānuka is likely to have undergone lower rates of erosion over the previous 65 years in comparison to areas of adjacent pasture. The combined findings of the three parts of the experimental work in this study are interpreted as being indicative of the present and future potential for South Island high-country farming environments to make a significant contribution towards climate change mitigation through vegetation management, resultant soil building and prevention of soil erosion. It is argued that closer attention to ecological restoration is likely to have mutual benefits for conservation, the farming system and the environment. Maintenance and better-informed management of the mosaic of native and exotic vegetation can play a more important role in longer-term sustainability of this high-country land management system than is currently appreciated.Publication Open Access Copper contamination of fruit orchards soils: Biotic Impacts : A thesis submitted in partial fulfilment of the requirements for the Degree of Doctor of Philosophy at Lincoln University(Lincoln University, 2024) Jeon, DasomExtensive use of fungicide copper (Cu) has a more recent history in New Zealand than in many other parts of the world where long-lasting Cu accumulation in soil has become a major environmental issue. However, Cu is extensively applied in New Zealand orchards, including organic orchards, with some awareness that the consequences of its current and future accumulation on soil health are relatively unknown and under-explored. This doctoral study aimed to investigate the impact on soil functional processes and plants of soil copper contamination associated with cherry, apple and kiwifruit orchards, vineyards and hops. The research encompassed experimental work on soil respiration, plant growth, earthworms, soil microbial activity, root growth and plant cell culture through a combination of fieldwork, glasshouse and laboratory studies. The central hypothesis of this study was that accumulation and persistence of Cu in orchard soils are likely to adversely affect critical aspects of soil biology and functionality. Following a detailed survey of accumulation and spatial variability of soil Cu across different fruit orchards up to 73 years old, practical investigations involved soil respirometry, analysis of microbial carbon (C) and nitrogen (N), and rhizobox and pot plant growth assays, as much as possible using in-situ field measurements or soils collected from orchards and transferred to the glasshouse and laboratory. In an earthworm behavioural and Cu-uptake study, a native anecic species was exposed to soils from the same orchard with differing histories of fungicide use. Three hop varieties (Cascade, Nelson Sauvin and Riwaka) were used for plant growth trials on the same soils. Plant stress responses were investigated using callus incubation trials on cell lines isolated from three apple cultivars (Braeburn, Fuji, and Cripps Pink) grown on a Cu-spiked growth medium. All practical work was carried out from 2020 to 2023. The results showed that soil Cu concentrations in orchards frequently and substantially exceeded most published threshold limits. Whilst soil Cu concentrations could largely be explained by modelling the age of the orchards, fruit type and soil organic matter (SOM) also had a large role in Cu retention. When SOM and existing Cu concentrations were amended in four soils from different blocks of the same cherry orchard, the ecotoxicological impact differed, and it was found that SOM could be a more powerful determinant than Cu of the biotic responses. Earthworm survivorship and growth in these soils were significantly determined by both SOM and Cu; earthworms exhibited a preference for soils with concentrations of Cu elevated substantially above background (to 160 mg kg-1), where SOM content was also high. A variable impact of Cu contamination on soil microbial activity was recorded across soils with elevated Cu concentrations (from 195 to 405 mg kg-1). Only a weak correlation was found between soil total Cu concentration and soil respiration when data for all orchards were combined, but the impact of Cu was more evident when each type of fruit orchard was evaluated separately. Microbial biomass carbon (MBC) and nitrogen (MBN) analyses similarly provided only a weak or negligible correlation with soil Cu, but artificially spiked soils provided a more consistent response to elevated Cu. Confounding factors appeared to relate to vegetation cover within and between rows and the amount of cultivation of the soils used to manage weeds (and bronze beetle in apples). The influence of management variables requires a more detailed study. Root growth in hop varieties was negatively affected at Cu concentrations exceeding 263 mg kg-1, whilst best growth was observed at 160 mg kg-1 in conjunction with abundant SOM. In callus culture assays, Cu negatively impacted the growth of Braeburn and Fuji apple varieties at concentrations exceeding 15 mg kg-1, while Cripps Pink had higher Cu tolerance. The value of using biological and ecological indices to assess the impacts of agricultural chemicals and contaminated soils is discussed. The findings have identified detrimental biotic impacts of soil Cu concentrations that already exist in orchards, which are probably reflected in a negative influence on soil health. Transfer rates of Cu to fruits through uptake from soil or from foliar absorption are negligible, but stress responses in plants and soil fauna and impacts on soil biology and ecology have been detected. Currently, the deleterious impact of elevated Cu is largely mitigated by SOM content in combination with the avoidance of low pH in orchard soils. Whilst this implies there is a potential avenue for amelioration of toxicity and maintenance or restoration of soil health, residual fungicide Cu will not significantly dissipate and is likely to continue to accumulate. Sustainable soil health management in New Zealand's orchards is not viable with longer-term continued usage of Cu fungicides.