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Investigation into the benthic vegetation of the upper Waikato River, New Zealand
(The University of Waikato, 1990) Miller, Suzanne Thelma; Silvester, Warwick B.; Clayton, John
The discharge of treated sewage from the Taupo Borough-Pollution Control Plant was associated with a dramatic change in downstream phytobenthos associations found in the Upper Waikato River. Displacement of epilthic moss assemblages by Cladophora, and domination of epiphyte habitats by Enteromorpha were observed downstream of this discharge. In essence, this situation is a species replacement series in response to a changing water quality gradient attributable to the inflow of treated sewage. Aerial photographs, transect surveys and drift diving showed that the extent of phytobenthos development through the entire length of the Upper Waikato River was primarily limited by substrate availability. Areas of gravel/pebble/sand were not immobile long enough in current flow to allow for the development of macroscopic vegetation either up- or downstream of the sewage discharge. However, there were similar stable habitats for phytobenthos development both up- and downstream of the sewage discharge. The greatest change in water quality attributable to the TBPCP discharge was increase in both NH₄-N (relative significance to all loads 61.5%) and DRP (relative significance to all loads 55.6%). However, even below the TB-PCP discharge average concentrations of NH₄-N (ca.10 mg m-³) and DRP (ca. 4 mg m-³) were still low and water may still be classified as oligotrophic. The ratio of TN-DON: TP-DOP is low in water leaving Lake Taupo (10.4), the inflow from the TBB-PCP sewage discharge further decreases this ratio to 6.2, measured at Reid’s Farm. A prediction of nitrogen limitation of algal growth was made from these low ratios. Nutritional studies of Oedogonium upstream of the TB-PCP sewage discharge supported the hypothesis of N limitation derived from N:P ratios. Oedogonium consistently exhibited tissue nitrogen levels below critical values. The same nutritional studies applied to Enteromorpha and Cladophora growths downstream of the TB-PCP sewage discharge showed that neither species was consistently limited by available N or P nutrients, and both species showed a greater susceptibility to N limitation. This was not expected from the predictions based on N:P ratios. Enteromorpha and Cladophora may be able to sustain adequate tissue N levels by maintaining high uptake rates. Both A A R and PUR rates were high for these species in the NATS monitoring programme. However, due to the high pulse concentration and the static nature of these techniques, results are not likely to be indicative of in-situ conditions. These results merely indicate that the algae have the capacity for high uptake rates. A greater relative importance of N compared to P inputs from the TB-PCP discharge for Enteromorpha and Cladophora growth was concluded from the pilot algae transplant experiment. Phosphorus tissue NATS did not show P limitation of upstream transplants after one and two weeks, compared to decreases in N tissue tests below critical levels. Results from this transplant experiment support the hypothesis that N concentrations in the Upper Waikato River above the TB-PCP discharge may be too low to support significant Enteromorpha and Cladophora growths. The increase in ammoniacal nitrogen from the TB-PCP discharge may represent a critical change for periphytic algal growth, given the physical environs of this river. Three new techniques have been trialled in this study: # use of a chain transect to survey phytobenthos of a deep, swift flowing river, # use of s15N signatures of plants growing up- and downstream of a point-source discharge in order to ascertain the extent of effluent N nutrient utilisation by plants growing downstream of the sewage discharge, # algae transplant experiment as a method for examining the relative importance of increased nutrient loads to changes in phytobenthos correlated to the inflow form point-source discharges. Preliminary application of these techniques has been useful in the Upper Waikato River to describe the biological impact of the TB-PCP discharge on benthic vegetation. In the Upper Waikato River phytobenthos associations found below the TB-PCP sewage discharge during 1989-1990 are not consistent with the ‘oligotrophic plant assemblage’ described by Coffey (1979). A major habitat degradation in the Upper Waikato River has occurred and is associated with the inflow from the Taupo Borough-Pollution Control Plant. No change in Coffey’s (1979) classification of ‘oligotrophic plant assemblage’ of the Waikato River from the Lake Taupo Control Gates to the upstream end of the point of inflow of the TB-PCP sewage discharge was concluded from this study.
Investigation of lipopolysaccharide binding protein in the bovine mammary gland
(The University of Waikato, 2004) Miles, Michelle Cara; Musgrave, David; Davis, Stephen R.; Stelwagen, Kerst
This study investigated the presence of LBP in the bovine mammary gland during varying stages of development and infection. The project was initiated by the discovery of an EST in a mastitic mammary cDNA library which bore homology to lipopolysaccharide binding protein (LBP). The results add to the understanding of the innate immune defences of the gland and the biological regulation of LBP. The expression profile of LBP in bovine mammary tissue was characterised by northern blot analysis which showed that LBP levels were increased in infected and involuted tissues. This is supported by the results from in situ hybridisation which detected local expression of LBP in epithelia surrounding ducts and alveoli in infected tissue. LBP was also shown to be increased in mammary secretions of whey and skim milk from infected and involuted glands by western blotting with an antibody that was raised against a peptide of LBP. These results were quantified by ELISA. The LPS-binding activity of the native protein was confirmed by ligand blotting, immunoprecipitation and ELISA. Attempts were made to investigate the immuno-stimulatory activity of LBP using a recombinant protein in a cytokine induction assay. Due to problems encountered with the expression system the results from this can not be accurately analysed and further optimisation is required. This is the first report of local expression of LBP in the mammary gland and taken together, these results suggest an important role for LBP in the local innate defence of the gland.
Supportive school environments as protective factors for psychological wellbeing in transgender secondary school students in Aotearoa New Zealand
(The University of Waikato, 2026) Hounsell, Jamie; Veale, Jaimie; Fenaughty, John
Young people in Aotearoa New Zealand face a mental health crisis, and this is especially dire for transgender and gender diverse youth, who are at significant risk of suicide. It is well established that trans youth experience high levels of bullying and discrimination, especially in schools, however comprehensive understandings of how social supports within school environments can buffer the effects of victimisation are less understood. This study aimed to investigate how social elements within secondary schools, such as safety, belonging, and teacher and classmate support, predict mental health difficulties in transgender students. Quantitative data drawn from 294 secondary school student participants from the 2022 wave of the Counting Ourselves survey was analysed using univariate analysis and logistic regressions. This study found that 90.1% of participants reported high or very high levels of psychological distress, 72.4% had engaged in NSSI, and 61.6% seriously considered committing suicide in the last 12 months. However, social supports within schools appeared to have a protective effect on student’s mental wellbeing. School safety was a significant protective factor all three mental health outcomes, and belonging and supportive classmates and adults were protective across analyses. These findings align with previous research that recommends that trans-inclusive policies in schools help trans students feel safe and accepted by their peers, which in turn can foster wellbeing. This study goes further by finding significant associations between school support and psychological outcomes. Overall, this emphasises the demand for inclusive school environments for transgender students and highlights the importance of social safety for marginalised groups.
Microclimate conditions of bat boxes occupied by New Zealand's native long-tailed bat (Chalinolobus tuberculatus) in Hamilton City
(The University of Waikato, 2026) O'Sullivan, Aimee; Tempero, Grant Wayne
Globally, land clearance has resulted in the destruction of bat habitat features such as tree roost cavities. Installation of artificial roosts, also known as bat boxes, is intended to mitigate such losses. However, bat boxes are often installed with limited understanding of conditions such as temperature stability and relative humidity required by the target bat species. In New Zealand, long-tailed bat/pekapeka-tou-roa (Chalinolobus tuberculatus) populations largely favour tree cavities for roosting, and populations have been documented across a range of habitats including native forest, agricultural land, and within urban areas such as Hamilton City. Temperature and relative humidity have been identified as important roost selection factors for C. tuberculatus, but these properties have never been assessed in New Zealand bat boxes. To understand microclimate conditions within bat boxes occupied by C. tuberculatus in relation to natural roosts, environmental loggers were installed in Kent and Schwegler type roost boxes in Hamilton City, and natural roost cavities near Hamilton and Pukekohe. For further comparison, loggers were also installed near the top and bottom of Grand Canyon Cave, a known roost for C. tuberculatus. Fortnightly surveys of Hamilton City bat boxes were conducted using an endoscopic camera mounted on a 15 m telescopic carbon fibre pole or evening watches of tree roosts. This provided box occupancy rates and allowed comparisons to be made between temperature and relative humidity within bat boxes and natural roosts in relation to occupancy. Twenty-nine (63 %) of the 46 monitored bat boxes had confirmed occupation, with generalised linear mixed modelling (GLMM) indicating that sheltered Kent boxes were more likely than exposed Kent boxes to be occupied. Modelling also indicated that there was no significant effect of box chamber on occupation. However, microclimate conditions of Kent boxes were less stable than natural roosts, particularly exposed boxes, although the differences may not have been substantive enough to be physiologically relevant to C. tuberculatus. On average, bat boxes were generally warmer or similar to ambient conditions on a diel cycle, while natural roosts were warmer than ambient at night and cooler during the day. Although heat tolerance of C. tuberculatus is unknown, criteria used for similar species indicated that two exposed Kent boxes experienced a limited number of potential overheating events (>40 °C). The microclimate conditions in Grand Canyon Cave indicated differences between the top and bottom of the cave, with the top of the cave having similar thermal properties to tree cavity roosts. Generalised linear mixed modelling indicated that there was no significant effect of box thermal conditions on occupation rates. Although microclimate differences between the inner and outer chambers of Kent type boxes were potentially too small to be physiologically relevant to C. tuberculatus, microclimate stability and box exposure should be considered during installation. Providing a range of internal microclimates is likely to support the range of thermoregulatory requirements of the population. Future research should consider the development of boxes with improved microclimate stability, and designs which facilitate the thermoregulatory requirements of C. tuberculatus during different reproductive phases.
At what cost?: Qualitative accounts of parents of young Autistic people navigating the transition to adulthood in Aotearoa
(The University of Waikato, 2026-01-12) Dib, Alex; Fox, Ririwai
Neurodevelopmental disorders are paradoxically over diagnosed and underdiagnosed, with autism being one of the most underdiagnosed disorders under the neurodivergence umbrella. Autism spectrum disorder is a neurodevelopmental disorder impacting functioning in social, cognitive, and physical domains. Research suggests that Autistic people experience poorer health and quality of life outcomes, lower academic attainment, higher unemployment, and particularly struggle during the transition from secondary education to adulthood (Shochet et al., 2022). Although an established knowledge base exists in this area, research seldom observes this transition in Autistic people in Aotearoa. Two focus groups were conducted with five mothers of Autistic children (ages 17 to 30). Participants identified key changes to support successful transitions, including greater involvement of people with lived experience in autism services, improved societal education about autism, enhanced diagnostic accuracy, and increased access to ongoing, targeted support. Thematic analysis identified five themes (At what cost, the shortcomings of systemic education, the bio-psycho-social-systemic view of Autistic youth, the transition to adulthood, and the mental health system). The analysis examined predisposing and precipitating factors contributing to adult transition-related obstacles across social, systemic, economic, and family domains. Results from the current study illuminate how Aotearoa-specific factors are impacting Autistic people today. Examining these factors may support the navigation of diagnosis, contribute to ongoing support, and the wellbeing of Autistic young people transitioning into adulthood.