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Response of micro-eukaryote and slime mould communities to land use change and pine invasion in Aotearoa
(2024) Cox, George R.
Soil micro-eukaryotes are a highly diverse group that drive key biogeochemical cycles and regulate the communities of other soil microorganisms, yet their responses to ecosystem changes in Aotearoa New Zealand are unknown. Micro-eukaryote communities are highly responsive to changes in soil conditions such as soil moisture and carbon availability, with these community level responses often differing from those of other soil biota. Human activity has changed many ecosystems in Aotearoa with the shift from native beech (Nothofagus sp.) to open shrublands, and now to exotic pine forests being one of the most notable. These large-scale changes in plant community composition have impacted animal, bacterial, and fungal communities within the soil, in addition to changing soil abiotic factors like nutrient ratios. This thesis aims to test the impacts of land use change and particularly pine invasion on soil micro-eukaryote communities in Aotearoa, to fill this research gap.
I extracted soil DNA from 33 sites in the Molesworth Recreation Reserve, with the sites being split between mountain beech (Nothofagus cliffortiodies) forest, native dominated grass-/shrublands, and invasive pine stands. A general eukaryote primer was used to generate OTUs (operational taxonomic units) via DNA metabarcoding to reveal the community level changes of micro- eukaryotes between different vegetation types. Slime moulds, a subgroup of micro-eukaryotes, were surveyed and cultured from these same sites to supplement the sequencing data.
DNA metabarcoding revealed that shrubland sites had significantly higher OTU richness and effective diversity than pine sites. Community dissimilarity (beta diversity) was also higher in shrubland sites than either beech or pine sites. The soil micro-eukaryote communities of all sites were dominated by the Cercozoa, with the Apicomplexa, Ciliophora, and Amoebozoa also identified as key soil micro-eukaryote groups in Aotearoa. The collected slime moulds did not significantly differ in diversity or community composition between vegetation types but did reveal multiple novel sequences and the detection of four species in Aotearoa for the first time. The slime mould communities of these sites were dominated by the genus Didymium, with most other slime moulds belonging to the family Physaraceae.
Land use change and pine invasion do impact the soil micro-eukaryote communities of Aotearoa, with pine invasion into shrublands leading to a reduction in micro-eukaryote diversity. However, these changes may be returning the soil micro-eukaryote community to a more natural state, as
beech and pines forests shared similar levels of diversity. The community level responses of micro-eukaryotes to anthropogenic changes differ from those seen in other soil biota where beech forest usually hosts the most diverse communities.
Further work should be done to identify the specific drivers of change in these micro-eukaryote communities. The taxonomy of the collected but unidentified slime moulds should be investigated further to either complete online sequence database or reveal novel taxa.
Ion implantation in β-Ga2O3 thin films
(2024) Sinclair, Andrew
As silicon devices are pushed to their physical limit, there is currently significant academic and commercial interest in wide band gap, and ultra wide band gap semiconductors which can operate at high power densities. One such semiconductor, β-Ga2O3, is seeing significant attention in recent years due to its high band gap (4.5 - 4.9 eV), and breakdown field (8 MV/cm) which makes it a desirable material for the manufacture of high power devices and photoelectronic devices operating in the deep ultraviolet (UV) region. n-type doping of β-Ga2O3 can be increased through the use of ion implantation with Si, Ge, and Sn substituting Ga in the crystal. Monte Carlo simulations of Si, Ge, and Sn implantation in β-Ga2O3 were undertaken to determine an implantation procedure that would result in a uniform dopant concentration of 1 × 1018 cm−3 and 1 × 1019 cm−3. This implantation procedure was used to implant Si into six thin films of Ga2O3, including two grown by Molecular Beam Epitaxy (MBE) on MgO (100) substrates, two by MBE on c-plane Al2O3 (c-Al2O3) substrates, and two grown by the sol-gel process on c-Al2O3. The implanted thin films underwent thermal annealing over a temperature range from 950 ◦C to 1100 ◦C to restore damage resulting from the implantation process. The effect of annealing on the electrical, optical, and material properties of the samples was examined using UV - Vis transmission spectroscopy, X-ray Diffraction (XRD) crystallography, Atomic force Microscopy (AFM), and Hall effect measurements. Electrical measurements indicated Si implantation failed to produce conducting thin films. Results of XRD measurements and UV-Vis transmission measurements indicate that this is likely due to the diffusion of Mg and Al in the substrates into the β-Ga2O3 films, which prevents the activation of Si by occupying Ga sites.
Making sense of Jane’s life and experiences as a woman farmer: the transformation of gender in agriculture
(2024) Mason-Sievers, Joanne
The farming industry in Aotearoa New Zealand has been predominantly patriarchal and women have traditionally played a support role to their farming husbands. Therefore, women have struggled to be recognised in their own right as farmers and is this still the case in 2023 to a considerable extent.
In order to discover what changes are occurring for women in farming and what continuities there are, I collected a life history/story by a women farmer Jane, who owns and runs a large dairy farm in Southland, as the sole farmer. This story of her life outlines the farming capital she gained over many years of farming in fields of masculine domination.
During the 35 years Jane has been farming many obstacles had to be overcome allowing her to firmly establish herself as a successful woman farmer today. Janes life history demonstrates some changes to the gender order of farming and these changes are highlighted in the narrative of Janes life. Key events in Jane’s life include surviving the death of her husband, becoming the sole farmer, managing public scrutiny, overcoming mental health issues, interacting with farming professionals, managing a biological disaster, navigating family dynamics, planning for farming succession, and finally succeeding as a farmer in the male dominated industry of farming. Jane’s story shines light on what was traditionally a patriarchal farming industry and how women are disrupting the gender order in farming today. However, there do appear to still be barriers in place for women to succeed in their own right and they are discussed throughout the life story, highlighting that not everything is changing for women in the farming sector and there is still some work to do around gender bias and the dominant discourse of patriarchal farming.
Drawing on the work of Bourdieu, I argue that Jane’s habitus is informed by the social spaces/fields she finds herself positioned in throughout her life. Additionally, the farming capitals she has gained over many years has shaped her experiences and perceived capabilities as a woman farmer.
Navigating a tunnel without sight: the experiences of children of parents with mental illness (COPMI) in Aotearoa New Zealand
(2023) George, Natasha
Children of parents with mental illness (COPMI) grow up with either episodic or enduring mental illnesses within their parents that shape their childhood and impact their entire family. COPMI research is important to the field of child and family psychology as parental mental illness influences child development, parenting experiences, and family functionality. International research on the felt experience of COPMI and subsequent impacts are well-established in international research with a notable gap on the recent experiences of tertiary students and children in Aotearoa New Zealand who have not engaged with a COPMI service. The aim of the study was to investigate the childhood experiences among COPMI tertiary students in Aotearoa New Zealand. Participants were five female tertiary students who had grown up in Aotearoa New Zealand and had a parent who had received psychiatric care. Each participant completed a semi-structured interview about their childhood which was transcribed and analysed using reflexive thematic analysis. Three subsequent themes were inductively generated and held together by the metaphor of navigating a tunnel without sight to illustrate how the participants navigated their parent’s mental illness. Each theme had three subthemes which followed a chronological order of their experiences of going from in the dark, growing eyes that see, to lighting a spark. The theme in the dark captured family secrecy about mental illness, inadequate support, and feeling stuck and alone. Second, the theme of growing eyes that see described their journey towards understanding as they experienced hypervigilance, a desire to understand, and positive outcomes. The final theme lighting a spark illustrated the felt connection between the past and the present as the participants felt the impacts of parental mental illness on the family system, talking and education helped, and they had a desire for change. Ultimately, the childhood experiences of COPMI had a profound and long-term impact, providing motivation and inspiration amongst their ongoing loss, frustration, and difficulties. The implications are relevant for a range of people, such as COPMI and their families, practitioners, and policymakers, with avenues for future research that are outlined for researchers.
Investigating the mental health of autistic trans youth in Aotearoa New Zealand
(2024) Jones, Harry M.
Youth who identify as either transgender or Autistic are part of highly stigmatised minority communities that suffer many inequities in mental health and wellbeing. In the face of marginalisation, Autistic trans communities are resilient, vibrant, and embody solidarity.
International research with Autistic trans youth has observed them to be at greater risk of anxiety, depression, and suicidality than the general youth population, and to have poorer mental health than their allistic trans peers. Previous research has shown that Autistic and trans communities in Aotearoa New Zealand each experience poorer mental health than the general population, however no studies have explored the experiences of Autistic trans communities who are likely to be at increased risk of psychological distress.
The current thesis explored the mental health experiences of Autistic trans youth in Aotearoa New Zealand using mixed methods. In Study 1, quantitative data from Counting Ourselves, a community-led health survey for trans people, was analysed to describe the mental health of Autistic trans youth (n = 432) and compare this to their allistic trans peers (n = 564). In Study 2, qualitative analysis of interviews with Autistic trans youth (N = 13) was undertaken to facilitate a
richer understanding of their mental health and determinants of this. Following a community-based approach to research, the current thesis included community perspectives in the research design, methods, language use, and interpretation of the research.
In Study 1, Autistic trans youth were observed to have poor self-rated mental health and life satisfaction, and high rates of loneliness, psychological distress, and suicidality. Both Autistic and allistic trans youth had poor outcomes across measures. It was found that Autistic trans youth had poorer mental health then their allistic trans peers across some measures including self-rated mental health, psychological distress, and lifetime suicidality. These results suggest that Autistic trans youth comprise a group at increased risk of negative mental health experiences.
In Study 2, reflexive thematic analysis detailed four themes and 19 subthemes related to the mental health experiences of Autistic trans youth, highlighting determinants of mental health including societal stigma, community connection, family acceptance, self-acceptance, and self- authenticity. The first theme was Identity Journeys, which had four subthemes: Conformity is Detrimental, Identity Self-Awareness Allows Understanding and Acceptance, Benefits of Self-
Understanding and Self-Acceptance, and Grief for What Life Could Have Been. This theme described how interviewees underwent a journey through painful conformity experiences toward self-authenticity as they came to awareness and acceptance of being Autistic and trans. The second theme was Finding Acceptance, which had four subthemes: Community Connection is Valuable, Ups and Downs of Acceptance and Rejection, Family Attitudes and Reactions are Important, and Family Should Be a Source of Acceptance. This theme described the importance of acceptance, and how interviewees’ mental health was impacted by others’ reactions toward their identities. The third theme was Societal Stigma, which had eight subthemes: Difficulties Living in Cisgender Neurotypical Society, Harmful Experiences of Hateful Incidents, Continual Expectations of Negativity, Lucky Not to Be Rejected, Masking for Safety and Social Fit, Managing Disclosure of Identities, Societal Misunderstanding of Identities, and Support Systems are Lacking. This theme described the myriad of ways that ableist and transphobic attitudes shaped interviewees’ interactions with society, leading to them feeling unwelcome and expecting to encounter negativity. The last theme was Inner Experiences, which had three subthemes: Identity Links to Mental Health Experiences, Gender Incongruence Distress and Relief, and Communication and Connection Difficulties. This theme described the links interviewees made between their Autistic and trans identities and their internal mental health experiences.
Overall, this research indicates that Autistic trans youth in Aotearoa New Zealand face high levels of societal stigma and challenges to their mental health, which contribute to their position as a group at increased risk of negative mental health experiences. The data from this research can be used to inform pathways to better support Autistic trans youth and work toward improving mental health inequities.