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The UC Research Repository collects, stores and makes available original research from postgraduate students, researchers and academics based at the University of Canterbury.



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ItemOpen Access
Lonely on limestone? A conservation genomics study of the Gentianella calcis complex.
(2024) Eastman-Densem, Robb William
Naturally fragmented or rare ecosystems are important components of terrestrial plant biodiversity. Unfortunately, many are also threatened through anthropogenic activities leading to increased extinction risk for their flora. In Aotearoa / New Zealand, the limestone areas of the eastern South Island / Te Waipounamu are a naturally fragmented and rare ecosystem of particular concern as they contain many highly threatened plant taxa. To assist with the ongoing conservation management of limestone endemic plants in New Zealand, the overall aim of this thesis was to explore patterns of genetic diversity and connectivity within a group of threatened limestone gentians (subspecies of Gentianella calcis and G. astonii) as well as investigate the interspecific taxonomic delimitation of G. calcis and G. astonii and infraspecific taxonomic delimitation of G. calcis. In Chapter 2, using Single Nucleotide Polymorphisms (SNPs) from 174 G. calcis and G. astonii samples genotyped through genotyping-by-sequencing (GBS), I aimed to determine the amount of genetic diversity in each subspecies and sampled population of G. calcis and G. astonii, assess the extent of genetic connectivity among them, and understand the geographic structuring of genetic diversity and its relationship to the environment. I show that all taxa are characterised by high population structure and limited genetic connectivity, with the presence of three main genetic groups corresponding to the South Canterbury and North Otago, Waipara, and North Canterbury and Marlborough regions. Although Isolation-By-Distance appeared to explain the observed patterns of genetic connectivity, potential adaptation to local climate and habitat soils was also seen. Patterns of observed heterozygosity potentially reflect past demographic histories as well as the effects of polyploidy-induced paralogy in some SNPs. Based on these findings, I designate conservation Management Units to assist with current and future conservation of G. calcis. DiscoSNP-RAD represents a novel SNP discovery approach that claims to not require the same parameter optimisation as other commonly used programs such as Stacks. There are very few published comparisons of its output to other SNP discovery programs, however, illustrating the need for empirical studies. Considering these factors, in Chapter 3 I aimed to assess the importance of using similarity-based parameters in SNP discovery by comparing both SNP discovery methods (i.e. Stacks and DiscoSNP-RAD) in terms of RAD loci assembled, data error, and population genetic inferences (e.g., estimates of population structure and genetic diversity). While both approaches provided similar patterns of population structure, estimates of genetic diversity and pairwise Fst differed between the two approaches. Using sample replicates, I show that this is likely due to increased SNP error in the DiscoSNP-RAD dataset, potentially reflecting a greater proportion of paralogy-induced SNPs caused by lower user control over the formation of RAD loci. Despite this, considering it has faster run-time and does not need extensive parameter optimisation, I suggest DiscoSNP-RAD is still a useful SNP discovery program. In Chapter 4, synthesising the learnings from Chapter 2 and Chapter 3, I make populationspecific management recommendations for each Gentianella calcis population along with taxonomic delimitation recommendations using knowledge of the genetic patterns in G. calcis and G. astonii. Considering that to date no conservation genetics or genomics studies have considered limestone plants in New Zealand at the population level, this research represents an important step towards the integration of genomic data into their conservation management.
ItemOpen Access
Applying behavioural science to understand and support biosecurity risk assessments.
(2024) Bain, Dominic
Invasive species threaten the health, safety, sustainability, wellbeing, and prosperity of Aotearoa New Zealand. A key function of the biosecurity system is to comprehensively assess the risks posed by invasive species. This study investigated the psychological dimensions of biosecurity risk assessments and explored potential targets and mechanisms for improvement. Twenty participants were recruited from Aotearoa New Zealand’s biosecurity workforce. Policy capturing, multiple-criteria decision analysis, and the behaviour change wheel were used as investigative frameworks. Results from the policy capturing analysis indicated that risks to economic, environmental, sociocultural, and te ao Māori values all significantly increased participants’ perception of invasive species’ overall biosecurity risk. Risks to economic values had the largest effect and risks to sociocultural and te ao Māori values had the smallest effects. Results from multiple-criteria decision analysis indicated that participants consciously allocated the most importance to risks to economic values followed by risks to environmental, then sociocultural, and then te ao Māori values. Results from the behaviour change wheel analysis indicated that participants were motivated to incorporate te ao Māori values into their biosecurity risk assessments but perceived that they lacked the capability and opportunity to do so. Key intervention targets and mechanisms were discussed to address these areas and support comprehensive biosecurity risk assessments.
ItemOpen Access
Japanese junior high school teachers’ perspectives on teaching English as a foreign language.
(2024) Tomita, Hanako
How do language teachers position grammar instruction and interaction in their teaching? This study postulated that, in a context where a communicative approach to language teaching is promoted over a structuralist/behaviourist approach, teacher perception of grammar instruction and interaction might be where the tension between the two approaches would surface. Exploration in this scope is relevant in Japan, where it has been twenty years since an action plan to nurture the national communicative skills in English was announced by the Ministry of Education, Culture, Sports, Science and Technology (MEXT) in 2003. The action plan prescribed the incorporation of learner-centred interactive teaching approaches, and the principles of the action plan continue to be enacted in the present Japanese national curriculum standards of junior and senior high schools (MEXT, 2017a; MEXT, 2018). Yet statistics indicate that Japanese students struggle in expressing themselves in writing and speaking (MEXT, 2019; MEXT, 2022). This study focused in on teacher perception on grammar instruction because extant literature suggests that language teachers hold persistent belief in transmitting explicit grammar rules for students’ deductive application, when research indicates that consciously attained explicit knowledge does not equate to language proficiency (Krashen & Terrell, 1983). Furthermore, the current study enquired into teacher views on interaction and bilingualism. Not only must teachers balance grammar instruction with dialogic activities, but their views of students as potential bi-/multilingual speakers might impact how they design a lesson. Based on a constructionist epistemology, relativism ontology, and a theoretical underpinning of Blumer’s (1969) symbolic interactionism, I conducted semi-structured interviews with 11 Japanese junior high school English-language teachers. A thematic analysis (Braun & Clarke, 2022) on the collected data demonstrated that teacher perceptions regarding grammar instruction, interaction, and bi-/multilingualism were varied, depicting fluidity and uncertainty around pedagogical choices among the participant teachers, but a tendency toward communicative language teaching and scepticism toward monolingual instruction. I conclude that more theory-based discussions would lead to teacher confidence in their practice.
ItemOpen Access
The biofactory : implementing a life cycle sustainability assessment decision making tool for quantifying integral sustainability benefits of the wastewater circular economy in Chile.
(2023) Furness, Madeline
The “Biofactory” is a circular economy-based concept for wastewater treatment that improves water quality, promotes efficient use of materials and energy, recovering resources, generating stakeholder collaboration, and decreasing both emissions and costs. This proposes a solution for the global challenge of integrated water and sanitation management. Due to socio-economic bottlenecks, such as typical high costs and low public acceptance of novel resource recovery scenarios in wastewater treatment, realizing the Biofactory goals becomes a difficult task. Decision makers are currently unable to appreciate the environmental and social benefits of the Biofactory, as most decision-making tools focus on mainly technical and economic aspects. This research is the first to quantify integral sustainability benefits of co-product recovery of treated effluent, biosolids, biogas and nutrient in two full-scale “Biofactory” wastewater circular economies in Chile. Life Cycle Sustainability Assessment (LCSA) was implemented, combining Life Cycle Assessment (LCA), Social Life Cycle Assessment (SLCA) and Life Cycle Costing (LCC) with a Multi-criteria Decision Making (MCDM) model to quantify integral environmental, socio-cultural, and economic sustainability impacts of two Plants, A and B. Three scenarios for each plant were considered, discharge of wastewater without treatment, conventional wastewater treatment with no resource recovery, and biofactory wastewater circular economy configurations, to determine if each plant decrease impacts and determine which had better performance. LCA results showed Plant A decreased overall environmental impact by -37 % compared to baseline conventional scenarios, while Plant B -31 %. SLCA results showed Plant A decreased social impacts – 56 %, while Plant B – 18 %, therefore, Plant A had better overall environmental and social performance. However, Plant B decreased economic impacts by -48 % compared to an increase of 20 % in Plant A. Therefore, when combining scores using a MCDM model, Plant A decreased total sustainability impacts by -30 % and Plant B by -58 %, therefore, the resource recovery systems implemented in Plant B had better overall sustainability performance. These results were discussed across process contributions to environmental, social, and economic benefits. Model limitations were discussed, and recommendations were made for future applications of this research. The investigation demonstrated that the transition to WW-CEs improved integral sustainability according to the LCSAMCDM model implemented in both Plants. The urgent need to adopt sustainable decision-making models was highlighted and discussed, to not only improve sanitation coverage, but also improve sustainability performance of the sanitation industry across the globe.
ItemOpen Access
Does a dimensionally-gated reselection process restrict the entry of visual features into working memory?
(2023) Williamson, Kieran James
Visual working memory (VWM) is a limited-capacity cognitive system that allows us to maintain and manipulate visual information over a brief period of time. It plays a critical role in many cognitive functions, including visual search, problem-solving, and decisionmaking. While the importance of VWM is not disputed, a critical issue addressed in research is whether visual objects bind all their component features during VWM entry or if task-relevant features are prioritised for representation. In a recent study, Zhu et al. (2022) proposed that attended sensory information does not automatically enter VWM, but instead is subject to an additional reselection process that determines whether items are selected for VWM entry. Furthermore, they suggested that reselection operates using a dimensional memory filter, such that when an individual feature value (e.g., red) is selected for entry into VWM, all attended feature values within the same feature dimension (e.g., all colours) automatically enter VWM. Across three experiments, we systematically investigated these hypotheses by conceptually replicating two of Zhu et al.’s experiments, while incorporating modifications to address our concerns about their methodology. In Experiment 1, we investigated Zhu et al.’s proposal that a reselection process operates to restrict the entry of features into VWM. We assessed whether the irrelevant colour of a target object captured more attention than a new colour when it appeared as a distractor singleton in an orthogonal visual search task. We found that this was the case, indicating that the irrelevant colour of the target object was held in VWM, contrary to the key result that Zhu et al. cited to support reselection. In Experiments 2 and 3, we investigated Zhu et al.’s claim that VWM consolidation operates via a dimensional memory filter. Specifically, we assessed whether memorising the colour of a fixation cross would cause the task-irrelevant colour of a target object to enter VWM. To determine whether this colour entered VWM, we measured its interference in an orthogonal shape change detection task. Experiment 2 used a 700 ms ISI, while in Experiment 3, we reduced the ISI to 100 ms. Unlike Zhu et al., who only reported trials where shape was consistent between displays, we included trials where shape changed between displays in our analysis and included trials in which the shape probe matched the memorised fixation colour. In Experiments 2 and 3, we found evidence that the target colour had entered VWM, consistent with a dimensional memory filter. However, we also found that the fixation colour had a stronger impact on shape change detection than the target colour, a finding that was not explicitly predicted by Zhu et al. Overall, our results align more closely with predictions from object-file theory (Kahneman et al., 1992) and event-file theory (Hommel, 1998, 2004), which propose object-specific binding occurs during encoding, and objectspecific benefits and costs emerge during object retrieval and review. The facilitation we observed when features were consistent between displays could reflect objectspecific repetition benefits, while the interference we observed when features partially changed between displays may indicate partial repetition costs.