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Item Applying structured decision making for large-scale wildlife management programmes : Project Janszoon as a case study : a thesis presented in partial fulfilment for the degree of Doctor of Philosophy in Conservation Biology at Massey University, Palmerston North, New Zealand(Massey University, 2024-11-30) Kenup, CaioManaging threatened populations is challenging due to the delicate balance between urgency and uncertainty. While swift action is often needed to prevent further decline or extinction, significant uncertainty frequently surrounds the effectiveness of various management strategies and the future trajectory of populations. This uncertainty complicates the identification of the most effective course of action, especially when resources are limited. Structured decision making (SDM) is an approach that supports informed decision making in the face of uncertainty in conservation projects. The primary aim of this thesis is to develop a decision making framework for Project Janszoon’s bird translocations, guiding management and monitoring decisions to maximise establishment and persistence probabilities for the kākā (Nestor meridionalis) and pāteke (Anas chlorotis). This framework can serve as a blueprint for implementing SDM and adaptive management (AM), promoting their broader use in conservation initiatives within New Zealand and beyond. In Chapter 2, I discuss expert elicitation techniques for generating predictions from expert knowledge while accounting for epistemic uncertainty. Numerical improvements in handling elicited data are proposed, focusing on aggregating and transforming expert-provided values while maintaining their associated uncertainty. Preserving this uncertainty is critical to avoid generating overconfident predictions from expert judgment. In Chapter 3, I explore which uncertainties are worth reducing and to what degree. Value of information (VOI) analysis offers a way to understand how reducing uncertainty affects decision making and conservation outcomes. A key insight from this chapter is that while monitoring is valuable for reducing uncertainty, such reductions do not always improve conservation outcomes. Beyond a certain point, further reductions in uncertainty do not alter decision making. Practitioners must estimate the optimal level of monitoring for each conservation challenge. In Chapter 4, I outline a passive adaptive management framework to reduce uncertainty as management actions are implemented and monitored. The framework’s extendable nature makes it adaptable to other management problems. The tools and concepts presented here are valuable assets for effective decision making for managed populations under uncertainty.Item Upscaling effects on infectious disease emergence risk emphasize the need for local planning in primary prevention within biodiversity hotspots(Springer Nature Limited, 2025-10-27) Muylaert RL; Wilkinson DA; Dwiyanti EI; Hayman DTSZoonotic risk assessments are increasingly vital in the wake of recent epidemics. The microbial diversity of parasitic organisms correlates with host species richness, with regions of high biodiversity facing elevated risks of emerging zoonotic infections. While habitat loss and fragmentation reduce species diversity, anthropogenic encroachment, particularly in forested areas, amplifies human exposure to novel pathogens. This study integrates host habitat, biodiversity, human encroachment, and population at risk to estimate novel disease emergence and epidemic risk at multiple spatial scales. Using Java, Indonesia, as a case study, we demonstrate that degrading spatial resolution leads to information loss, with optimal resolutions typically below 2000 m, ideally around 500 m when native-resolution processing is unfeasible. Gravity models of epidemic spread highlight Jakarta and West Java as high-risk areas, with varying contributions from surrounding regions. Our spatial analysis underscores the influence of population centers on forest management and agroforestry practices. These findings offer valuable insights for guiding pandemic prevention research and improving pathogen- and driver-based risk monitoring strategies.Item Application of diagnostic tools for optimised treatment and management of coccidiosis in kiwi (Apteryx spp.) : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy (PhD) in Veterinary Sciences at Massey University, Manawatū, New Zealand. EMBARGOED to 24 January 2027.(Massey University, 2024) Scheltema, Emma MargaretCoccidiosis, a disease caused by infection with the protozoan parasite, Eimeria spp., is currently the main limiting disease in captive and creche-reared kiwi and can cause significant morbidity and mortality in young birds. There are at least five species of Eimeria that infect kiwi, and they are usually present as a mixed species infection. These parasites cause damage to tissues of the intestine and occasionally to other organs including the liver, kidneys, lungs, and spleen. Infection is managed in captivity through husbandry and medication, primarily via therapeutic treatment with the anticoccidial, toltrazuril (Baycox®, Bayer, Leverkusen, Germany). However, there is some evidence that this drug is not always effective, and there has been no research to date into safe and effective alternatives. Thus, effective management of this disease in infected birds is limited by a lack of evidence-based therapeutic options. The overall objective of this study was to improve the detection and diagnosis of kiwi Eimeria spp. through the development of a molecular tool, that could then be applied to assist in identifying safe and effective prophylactic and/or therapeutic treatments for the control of coccidiosis in kiwi chicks. To achieve this, we developed a molecular diagnostic tool (qPCR) to measure the diversity of Eimeria species present in mixed infections in kiwi. This tool was applied to preserved tissue samples to identify the tissue specificity (in intestine, liver, kidney, lungs, and spleen) of different kiwi Eimeria species, which may have consequences for the success of drug treatment. Following the development of normal blood biochemical and haematological reference intervals in healthy kiwi chicks as a baseline, a safety and pharmacokinetic study of five anticoccidial drugs (amprolium 15mg/kg, decoquinate 0.5mg/kg, diclazuril 5mg/kg, trimethoprim-sulphamethoxazole 20:100mg/kg and toltrazuril 25 mg/kg) given as single doses to healthy kiwi chicks was carried out. We then trialled one of these drugs, diclazuril, given both prophylactically in-feed (0.5mg/kg q24h) and as a therapeutic treatment (5mg/kg single dose) in naturally infected kiwi in a field study at a captive-rearing centre. In combination with standard faecal oocyst counts, the molecular tool was used to assist in Eimeria species identification from faecal samples from treated and untreated birds. We were able to establish the presence of a single Eimeria species infecting extra-intestinal tissues, described here as Eimeria koka, and isolated another species Eimeria kiwii from the intestine. Baseline biochemical and haematological parameters and the safety and pharmacokinetics of four anticoccidial drugs were established in healthy three-to-four-week-old kiwi chicks. We were unable to determine the pharmacokinetics of one of the drugs, decoquinate. The use of diclazuril in-feed was well-tolerated by kiwi chicks and while there was no observed difference in body weight or feed intake between treated and untreated control chicks, diclazuril-treated birds shed significantly fewer oocysts than control chicks. A small number of birds were dosed therapeutically with diclazuril, and we observed a decrease in oocyst shedding equivalent to the toltrazuril-treated control group (standard management), however, more data is required to confirm this pattern. Not all kiwi Eimeria species were found to be equally susceptible to treatment with diclazuril, with changes in species composition observed in treated kiwi. The molecular assay developed in this study has a range of applications to address questions about kiwi Eimeria biology and control. We hypothesise that the newly described Eimeria koka is likely the only Eimeria species infecting kiwi that migrates extra-intestinally, to infect the kidneys, and under severe infections, probably disseminates to other organs. Further testing of the response of this species to drug treatment is required; it is likely more challenging to treat due to its location in the body. All drugs trialled in kiwi appear to be relatively safe at the given doses. Diclazuril appears to be partially effective in the prevention and therapeutic treatment of coccidiosis in kiwi. Further investigation into dose rate and period, and the addition of other safe and effective drugs to build a sustainable, rotational drug dosing scheme is highly recommended before the integration of any new treatments into captive management protocol. This study is the first to establish the safety and pharmacokinetics of anticoccidial drugs in kiwi, and to demonstrate the efficacy of diclazuril to treat coccidia infection in kiwi. The methods developed herein lay the foundation for establishing the safety and efficacy of other drugs for treating this disease and will ideally contribute towards the development of more sustainable coccidiosis management plans for kiwi. The identification of optimum treatments for coccidiosis in kiwi is of high importance for the ongoing maintenance of captive-reared kiwi health and welfare, and the success of this form of ex-situ conservation intervention.Item Wild bovid habitat and infectious disease risk in Thailand : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Veterinary Science, School of Veterinary Sciences, Massey University(Massey University, 2024-11-07) Horpiencharoen, WantidaWild bovids are a diverse group of typically large, hoofed ruminant mammals that play crucial functions in ecosystems as seed transporters and prey for predators to maintain biodiversity. However, their conservation status varies from least concern to critically endangered with extinction, depending on the regions and remaining population. The expansion of agricultural areas and livestock farming has led to habitat loss and natural resource sharing, likely increasing the risk of disease transmission and pathogen circulation between humans, wildlife, and domestic animals at the shared habitats or the interface areas. This thesis aims to identify the habitat suitability of five wild bovids remaining in Thailand, understand the consequences of introducing infectious disease into the population, and identify where there is a risk of disease transmission. Therefore, three main studies were conducted: 1) identifying suitable areas for five wild bovid species, including gaur, banteng, wild water buffalo, mainland serow and Chinese goral in Thailand; 2) simulating the impact of infectious diseases of cattle on wild bovid populations, and; 3) mapping potential risk areas between wild bovids and cattle. Initially, I used ecological niche modelling to identify the habitat suitability of five wild bovids remaining in Thailand. Due to poor model predictions for two species (mainland serow and Chinese goral), I excluded these two models from further analyses. The results indicated that over 50% of the potentially suitable areas for the three modelled species (gaur, banteng, wild water buffalo) were located outside protected areas close to human populations and agricultural areas. Then, I simulated the number of animals in a model gaur population with and without infections over 100 years with 100 repetitions using stochastic mathematical models. I selected six bovine infectious diseases with different traits, such as incubation and infectious periods or fatality probabilities, including anthrax, bovine tuberculosis, haemorrhagic septicaemia, lumpy skin disease, foot and mouth disease and brucellosis. I introduced an individual infected animal into a closed population for each infectious disease. The disease-free gaur population grew over time, with infections with different traits having different impacts. The populations infected with chronic diseases (e.g. bovine tuberculosis and bovine brucellosis) showed the greatest decline, while diseases with high mortality but acute disease or high transmission rates with low mortality had less impact on the populations. Finally, I mapped the potential risk areas for disease transmission, assuming that high cattle density and habitat suitability increased transmission risk between wild bovids and livestock. The results also indicated that the potential high-risk areas were at the interface areas at the forest edges where interactions between wildlife and cattle occur. All my studies and findings will require further investigation and validation to gain a deeper and better understanding of the complexity of infectious diseases within wildlife populations and the dynamics of their distributions, but they contribute to supporting wildlife conservation and implementing disease mitigation measures to prevent disease transmission among the populations by highlighting where wild bovids might have suitable habitat, what types of infections may be problems and where mitigation may be better targeted.Item To disturb or not disturb : radio-telemetry based territory mapping and camera traps for monitoring cryptic species using Rakiura tokoeka (Apteryx australis australis) : a thesis presented in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Conservation Biology at Massey University, Albany, New Zealand(Massey University, 2024) Feenstra, EmmaSuccessful wildlife conservation is dependent on effective population monitoring. The objectives of monitoring can be multi-faceted, but population density is often coveted. However, estimating the density of species in which individuals cannot be identified is challenging without a complete census, which is rarely possible. In New Zealand, kiwi (Apteryx spp.) are morphologically and behaviourally cryptic species that are difficult to monitor, yet monitoring results are essential to their conservation. The gold standard of kiwi monitoring is territory mapping using radio-telemetry, yet this method had never been formally evaluated, and the alternative method is call counts, which are difficult to relate to population variables. Using Rakiura tokoeka (Apteryx australis australis) as my case study species, I implemented territory mapping with radio-telemetry at two novel locations on Rakiura/Stewart Island, one a pest-free island. My aim was to establish ‘known’ populations (minimum densities), and evaluate the traditional territory mapping method (Robertson, 2018) by comparing different ways of establishing territory boundaries (field-workers-estimates, convex 100% and concave polygons) and incorporating increasing numbers of locations by extending the length of the surveys. In these two study locations, and an additional two locations where historical territory mapping surveys of Rakiura tokoeka had provided minimum density estimates, I then trialled a novel method for monitoring kiwi populations, camera trap grids. I ran camera trap surveys for Rakiura tokoeka seasonally between 2018 and 2020 in the four locations, using the same study areas that were used for territory mapping. I used the data from the camera surveys in two ways, firstly for a relative abundance index (calculating camera trap rate), and secondly in a statistical abundance model that estimated point abundance and detection probability (Royle-Nichols, 2003). I also evaluated the use of radio-telemetry and camera traps for monitoring Rakiura tokoeka through the breeding season and providing information on the survival, growth, and dispersal of young Rakiura tokoeka. I found that territory mapping using radio-telemetry is an effective monitoring method for establishing minimum densities of Rakiura tokoeka, but that current methods could be improved. Convex polygon territory boundaries were similar to field-workers-estimate boundaries but could be applied more objectively and increasing the number of location fixes decreased density estimates. Camera trapping was an effective monitoring method for Rakiura tokoeka populations. Camera trap rates were an easy to apply index that is widely applicable to the many community and conservation groups working with kiwi that do not have access to radio-telemetry for monitoring. Camera trap rates indicated that the pest free island (Ulva Island) had lower detections of Rakiura tokoeka than the other three locations. This could have been due to lower densities of Rakiura tokoeka over some parts of the island, or lower detection probabilities. From the abundance model, estimates of density of Rakiura tokoeka at the four locations were not significantly different to those from territory mapping. This indicated that camera trap surveys could be used as a non-invasive alternative to territory mapping with radio-telemetry for Rakiura tokoeka, and potentially other kiwi species that has lower cost and requires less effort. I found the use of radio-telemetry and camera traps effective for monitoring different aspects of breeding behaviour, nesting, and chick variables, with the best use being a combination of the two methods. From the data collected on age structure, breeding and survival, I found no reason for immediate concern or management intervention for the Rakiura tokoeka population. This project shows the importance of questioning established methods, trialling new methods, combining methods, and considering whether the invasiveness of a method is warranted to meet the project objectives.Item Rhododendron taxonomy and diversity of ex situ collections for conservation : (subsection) Maddenia species as a case study : a thesis presented in the partial fulfilment of the requirements for the degree of Doctor of Philosophy (PhD) in Agriculture and Horticulture at Massey University (Manawatū campus], Palmerston North, New Zealand(Massey University, 2024-02-01) Hu, LingIn the ‘big genus’ Rhododendron of over 1,000 species, more than half of the species are threatened, at risk, or lacking data for biodiversity conservation. Ex situ collections, especially those from the wild, are crucial for safeguarding the diversity of species. However, lack of knowledge on existing wild diversity in botanic garden collections, and complex taxonomy, are two main problems in species assessments and conservation decision making. This research studied subsection Maddenia, a group of ~65 taxa encountering the two problems but seldom studied, as an exemplar to investigate species taxonomy and ex situ diversity. An ex situ conservation gap analysis was undertaken, using ecogeographical representation as a proxy for genetic representation in current botanic garden collections worldwide. Fifty-five of the total 65 taxa were found in cultivation, with over 86% of the living collections conserved in 66% of global botanic gardens. Half of the 18 threatened taxa, and nine of the 12 Data Deficient taxa require further wild collection to achieve a minimum level of ecogeographical representation in ex situ collections. Occurrence of ex situ collections in countries of origin is limited, and the distribution of ex situ collections worldwide is northern hemisphere centric. The results highlight the necessity of having more ex situ collections in the 10 native countries, and the importance of inter-institutional data sharing and robust documentation of collections. Determination of ploidy level of species was the second study, as the presence of polyploid samples may affect phylogenetic analysis. Ploidy levels were estimated for 263 accessions of 47 taxa (including 135 wild accessions) using flow cytometry. Meiotic chromosomes were counted for representative species of both diploids and polyploids to verify the flow cytometry results. This study showed that all taxa except one were diploid. The exception was that polyploids (2–8x, 12x) occur in the R. maddenii complex, where only seven of the 62 accessions tested were diploid while the rest were polyploid. This high level of polyploidy, combined with (i) the wide geographical distribution of the R. maddenii complex, and (ii) the previous ‘lumping’ of 12 taxa into the two subspecies, suggests the possibility of either some cryptic species or the need to re-evaluate some of the synonymized species. If new species were revealed, some may require conservation action. However, a greater number of wild-collected accessions and of different geographic origins are needed to explore this possibility. Following the ploidy study, molecular phylogeny of 40 taxa, including diploids and polyploids, was analysed using target capture sequencing. Phylogenetic trees from maximum likelihood and Bayesian analyses largely supported the morphological groupings of the Maddenii Series, Ciliicalyx Subseries and Megacalyx Subseries, but not the Ciliatum Subseries as classified by Davidian (1982). Of particular interest was the clustering in one clade of all of the R. maddenii complex, including all polyploid samples. This occurred irrespective of the method of analysis; however, there was no clear pattern of relationships to ploidy levels within the clade. The molecular phylogeny delimited several species and suggested a revision of the boundary of ‘subsection Maddenia’, although further research, to include a wider range of species, is needed to determine whether the new boundaries should be wider or narrower than before. The feasibility of using controlled pollination for safeguarding germplasm of prioritised species in ex situ collections was studied. Fruit set and seed germination identified the self- and cross-incompatibility of R. excellens (Vulnerable), which requires methods other than controlled pollination to conserve the intraspecific diversity in botanic gardens. R. dalhousiae var. dalhousiae (Least Concern), R. dalhousiae var. rhabdotum (Vulnerable), R. lindleyi (Least Concern), and R. nuttallii (Near Threatened) were both self- and cross-compatible, but the compatibility between self and cross pollinations differed from taxon to taxon and from accession to accession. These results suggest the choice of intraspecific pollination should be tested for each species before a programme of propagation is initiated. These aspects studied for subsection Maddenia can be immediately applied to conservation of this group of plants by working with the Global Conservation Consortium for Rhododendron. Meanwhile, the methods used here provide an exemplar for investigating other Rhododendron species or plant groups that encounter similar problems, to guide conservation efforts.Item Gut microbiota of the threatened takahē: biogeographic patterns and conservation implications(BioMed Central Ltd, 2022-12) West AG; DeLaunay A; Marsh P; Perry EK; Jolly M; Gartrell BD; Pas A; Digby A; Taylor MWBACKGROUND: The Aotearoa New Zealand takahē (Porphyrio hochstetteri), once thought to be extinct, is a nationally threatened flightless rail under intensive conservation management. While there has been previous research into disease-related microbes in takahē, little is known about the microbes present in the gastrointestinal tract. Given the importance of gut-associated microbes to herbivore nutrition and immunity, knowledge of these communities is likely to be of considerable conservation value. Here we examined the gut microbiotas of 57 takahē at eight separate locations across Aotearoa New Zealand. RESULTS: Faecal samples, taken as a proxy for the hindgut bacterial community, were subjected to 16S rRNA gene amplicon sequencing using Illumina MiSeq. Phylogenetic analysis of > 2200 amplicon sequence variants (ASVs) revealed nine main bacterial phyla (Acidobacteriota, Actinobacteriota, Bacteroidota, Campilobacterota, Firmicutes, Fusobacteriota, Planctomycetota, Proteobacteria, and Verrucomicrobiota) that accounted for the majority of sequence reads. Location was a significant effect (p value < 0.001, 9999 permutations) that accounted for 32% of the observed microbiota variation. One ASV, classified as Lactobacillus aviarius, was present in all samples at an average relative abundance of 17% (SD = 23.20). There was strong evidence (p = 0.002) for a difference in the abundance of the genus Lactobacillus between locations. A common commensal bacterium previously described in takahē, Campylobacter spp., was also detected in most faecal samples. CONCLUSIONS: Location plays a pivotal role in the observed variation among takahē gut bacterial communities and is potentially due to factors such as supplemental feeding and medical treatment experienced by birds housed in captivity at one of the eight sampled sites. These data present a first glimpse of the previously unexplored takahē gut microbiota and provide a baseline for future microbiological studies and conservation efforts.Item Marine mammal conservation: over the horizon(Inter-Research, 2021-03-25) Nelms SE; Alfaro-Shigueto J; Arnould JPY; Avila IC; Nash SB; Campbell E; Carter MID; Collins T; Currey RJC; Domit C; Franco-Trecu V; Fuentes MMPB; Gilman E; Harcourt RG; Hines EM; Hoelze AR; Hooker SK; Johnston DW; Kelkar N; Kiszka JJ; Laidre KL; Mangel JC; Marsh H; Maxwe SM; Onoufriou AB; Palacios DM; Pierce GJ; Ponnampalam LS; Porter LJ; Russell DJF; Stockin KA; Sutaria D; Wambiji N; Weir CR; Wilson B; Godley BJ; McMahon CMarine mammals can play important ecological roles in aquatic ecosystems, and their presence can be key to community structure and function. Consequently, marine mammals are often considered indicators of ecosystem health and flagship species. Yet, historical population declines caused by exploitation, and additional current threats, such as climate change, fisheries bycatch, pollution and maritime development, continue to impact many marine mammal species, and at least 25% are classified as threatened (Critically Endangered, Endangered or Vulnerable) on the IUCN Red List. Conversely, some species have experienced population increases/recoveries in recent decades, reflecting management interventions, and are heralded as conservation successes. To continue these successes and reverse the downward trajectories of at-risk species, it is necessary to evaluate the threats faced by marine mammals and the conservation mechanisms available to address them. Additionally, there is a need to identify evidence-based priorities of both research and conservation needs across a range of settings and taxa. To that effect we: (1) outline the key threats to marine mammals and their impacts, identify the associated knowledge gaps and recommend actions needed; (2) discuss the merits and downfalls of established and emerging conservation mechanisms; (3) outline the application of research and monitoring techniques; and (4) highlight particular taxa/populations that are in urgent need of focus.Item A novel gyrovirus is abundant in yellow-eyed penguin (Megadyptes antipodes) chicks with a fatal respiratory disease.(2023-02) Wierenga JR; Morgan KJ; Hunter S; Taylor HS; Argilla LS; Webster T; Dubrulle J; Jorge F; Bostina M; Burga L; Holmes EC; McInnes K; Geoghegan JLYellow-eyed penguins (Megadyptes antipodes), or hoiho in te reo Māori, are predicted to become extinct on mainland Aotearoa New Zealand in the next few decades, with infectious disease a significant contributor to their decline. A recent disease phenomenon termed respiratory distress syndrome (RDS) causing lung pathology has been identified in very young chicks. To date, no causative pathogens for RDS have been identified. In 2020 and 2021, the number of chick deaths from suspected RDS increased four- and five-fold, respectively, causing mass mortality with an estimated mortality rate of >90%. We aimed to identify possible pathogens responsible for RDS disease impacting these critically endangered yellow-eyed penguins. Total RNA was extracted from tissue samples collected during post-mortem of 43 dead chicks and subject to metatranscriptomic sequencing and histological examination. From these data we identified a novel and highly abundant gyrovirus (Anelloviridae) in 80% of tissue samples. This virus was most closely related to Gyrovirus 8 discovered in a diseased seabird, while other members of the genus Gyrovirus include Chicken anaemia virus, which causes severe disease in juvenile chickens. No other exogenous viral transcripts were identified in these tissues. Due to the high relative abundance of viral reads and its high prevalence in diseased animals, it is likely that this novel gyrovirus is associated with RDS in yellow-eyed penguin chicks.Item Ex situ conservation of Myrtaceae : a response to myrtle rust in the Pacific Region : a thesis presented in partial fulfilment of the requirements for the degree of Doctoral of Philosophy (PhD) in Plant Science at Massey University, Palmerston North, New Zealand(Massey University, 2022) van der Walt, KarinMany Myrtaceae species are threatened with extinction due to the arrival of myrtle rust (Austropuccinia psidii) in the Pacific Region. Ex situ conservation, in particular seed banking and cryopreservation, requires knowledge of the seed biology of the species to develop optimum long-term seed storage protocols. This information is limited for many New Zealand species. This study investigated ex situ conservation options for five critically endangered Myrtaceae species; Lophomyrtus bullata (ramarama), Lophomyrtus obcordata (rōhuto), Neomyrtus pedunculata (rōhuto), Metrosideros bartlettii (rātā moehau) and Syzygium maire (swamp maire). Less than 14 individuals of M. bartlettii remain in the wild. Using six trees in cultivation, the breeding system was found to be self-incompatible, thus an unrelated pollen donor is required to produce viable seed. With many trees in cultivation closely related, hand-pollination is an essential management tool. For hand-pollination to be successful, viable pollen must be available at the precise time. This study compared viability of pollen sourced from different trees and for the same tree over two years. Pollen germination protocols, which can be used to quantify pollen viability, were developed while short- and medium- term pollen storage methods are described. The seed morphology, seed germination requirements, seed desiccation tolerance, the combined impact of desiccation and freezing, and storability at 5°C, -18°C and -196°C of Lophomyrtus bullata, L. obcordata and Neomyrtus pedunculata were investigated. All three species were found to have intermediate seed storage physiology. L. bullata and N. pedunculata were sensitive to desiccation (~15% equilibrated relative humidity). Lophomyrtus bullata was also found to be freezing sensitive, while two of the three L. obcordata seed lots tested also displayed significant seed viability loss following storage at -18°C. Differential Scanning Calorimetry (DSC) analysis revealed that lipid crystallization in all three species occurred between -18°C and -52°C, and it is postulated that the lipids are in a metastable state when stored under conventional seed banking temperatures (c. -18°C). It is recommended that seeds of these three species are best stored outside of their lipid metastable temperature ranges. Syzygium maire seed and embryos are highly recalcitrant. This study investigated the oxidative stress, thermal properties, and ultrastructure of zygotic embryo axes (EAs) desiccated to various moisture contents (MC). Using rapid desiccation, moisture content in EAs were lowered to ~0.3 g/g resulting in ~50% of the EAs surviving. Exposure to liquid nitrogen was however fatal irrespective of the moisture contents tested. The enzymatic antioxidants superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPOX) significantly decreased following desiccation, while there was a corresponding 7-fold increase in the production of protein carbonyls and lipid peroxides. Exogenous application of ascorbic acid (AsA) increased antioxidant activity in desiccated EAs but not by a significant amount. The decrease in antioxidant activity following desiccation as well as the presence of melt enthalpies observed on the DSC thermograms, confirmed that for cryopreservation of S. maire EAs to be successful, rapid desiccation needs to be combined with cryoprotection. Plant Vitrification Solution 2 (PVS2) moderated the thermal behaviour in S. maire EAs with the novel droplet vacuum infiltration vitrification (DVIV) significantly improving embryo survival and plantlet development compared to droplet vitrification (DV). Neither method however resulted in embryo survival following exposure to liquid nitrogen. Longer incubation times using DVIV combined with physical desiccation should be investigated for the cryopreservation of S. maire. The four fleshy New Zealand Myrtaceae species, Lophomyrtus bullata, L. obcordata, Neomyrtus pedunculata and Syzygium maire were not amenable to conventional seed banking. Seed from Lophomyrtus and Neomyrtus displayed intermediate storage physiology due to sensitivity to desiccation and storage at -18°C, while S. maire seeds were highly recalcitrant. Cryopreservation, including the use of cryoprotectants and optimisation of cooling/warming rates, should be investigated for Lophomyrtus and Neomyrtus. Syzygium maire embryos did not regenerate successfully following any of the cryopreservation methods tested in this study (rapid desiccation, encapsulation-dehydration, cryoprotection). Further optimisation of cryopreservation methods for S. maire should be investigated. This includes application of exogenous antioxidants, increased cooling/warming rates, longer PVS2 incubation times and combining DVIV and rapid desiccation.
