title: Implications of sea-level rise on estuarine benthic biodiversity and ecosystem functioning

authors: Dixon, Olivia Jane

abstract: Estuarine habitats are among the most productive ecosystems around the globe. The macroinvertebrate communities within these habitats underpin ecosystem functioning and therefore the provision of ecosystem services valued by society. Due to their geographic positioning, coastal areas represent a human-ocean interface and are consequently at the forefront of anthropogenic pressure. Sea-level rise (SLR) is one major consequence of anthropogenic climate change that poses a great threat to coastal environments and will result in extensive intertidal area loss. There is an evident bias within coastal SLR research towards the implications for the abiotic environment such as impacts on geomorphology but the ecological implications however, have been largely overlooked despite their likely significance. In this thesis, I aim to address this knowledge gap by investigating how benthic macroinvertebrate communities and their contributions to ecosystem function will respond to SLR within a large temperate estuary. To explore how benthic macroinvertebrate community structure will respond to future SLR, I employed a space-for-time approach. In this study, I considered site depth as a proxy for SLR to gauge how macroinvertebrate communities may shift with increasing depth as sea level is elevated. This study was based on data obtained from 119 unvegetated soft-sediment sampling locations throughout Tauranga Harbour. An initial hierarchical cluster analysis was performed on the macroinvertebrate abundance data to reveal groups of sites that shared significantly similar community structure. Three clusters of sites were identified at a > 34% similarity level with significantly different macroinvertebrate community structure. Clustered groups were generally characterised by different depth ranges that we could consider representative of intertidal, shallow subtidal and deep subtidal habitats. Similarly, depth was identified as the most important environmental variable for predicting variation in macroinvertebrate community structure using distance-based linear modelling (explaining 12%) and gradient forest analysis indicated it is important in explaining rates of compositional turnover (6%). Chl-a, mud content and average current speed were among the next most important predictors explaining variation in community structure (5%, 4% and 2%, respectively) and compositional turnover (6%, 3%, 4%, respectively). Functional trait analysis indicated low functional redundancy for a key intertidal suspension-feeding bivalve (Austrovenus stutchburyi) and the lack of a shallow subtidal functional replacement should intertidal habitats become inundated by SLR. The findings of this thesis strongly suggest SLR and the associated environmental changes will significantly alter estuarine macroinvertebrate communities, indicating implications for ecosystem function and resilience. Key findings of this thesis will complement management strategies of coastal areas and encourage they are not treated as static systems as ecological shifts are predicted to occur with SLR over time. Well- informed management of important estuarine habitats that recognises their spatial and temporal dynamicity will be critical for ensuring ecosystem functions and services they deliver will be conserved for future generations.

text: Implications of sea-level rise on estuarine benthic biodiversity and ecosystem functioning Estuarine habitats are among the most productive ecosystems around the globe. The macroinvertebrate communities within these habitats underpin ecosystem functioning and therefore the provision of ecosystem services valued by society. Due to their geographic positioning, coastal areas represent a human-ocean interface and are consequently at the forefront of anthropogenic pressure. Sea-level rise (SLR) is one major consequence of anthropogenic climate change that poses a great threat to coastal environments and will result in extensive intertidal area loss. There is an evident bias within coastal SLR research towards the implications for the abiotic environment such as impacts on geomorphology but the ecological implications however, have been largely overlooked despite their likely significance. In this thesis, I aim to address this knowledge gap by investigating how benthic macroinvertebrate communities and their contributions to ecosystem function will respond to SLR within a large temperate estuary. To explore how benthic macroinvertebrate community structure will respond to future SLR, I employed a space-for-time approach. In this study, I considered site depth as a proxy for SLR to gauge how macroinvertebrate communities may shift with increasing depth as sea level is elevated. This study was based on data obtained from 119 unvegetated soft-sediment sampling locations throughout Tauranga Harbour. An initial hierarchical cluster analysis was performed on the macroinvertebrate abundance data to reveal groups of sites that shared significantly similar community structure. Three clusters of sites were identified at a > 34% similarity level with significantly different macroinvertebrate community structure. Clustered groups were generally characterised by different depth ranges that we could consider representative of intertidal, shallow subtidal and deep subtidal habitats. Similarly, depth was identified as the most important environmental variable for predicting variation in macroinvertebrate community structure using distance-based linear modelling (explaining 12%) and gradient forest analysis indicated it is important in explaining rates of compositional turnover (6%). Chl-a, mud content and average current speed were among the next most important predictors explaining variation in community structure (5%, 4% and 2%, respectively) and compositional turnover (6%, 3%, 4%, respectively). Functional trait analysis indicated low functional redundancy for a key intertidal suspension-feeding bivalve (Austrovenus stutchburyi) and the lack of a shallow subtidal functional replacement should intertidal habitats become inundated by SLR. The findings of this thesis strongly suggest SLR and the associated environmental changes will significantly alter estuarine macroinvertebrate communities, indicating implications for ecosystem function and resilience. Key findings of this thesis will complement management strategies of coastal areas and encourage they are not treated as static systems as ecological shifts are predicted to occur with SLR over time. Well- informed management of important estuarine habitats that recognises their spatial and temporal dynamicity will be critical for ensuring ecosystem functions and services they deliver will be conserved for future generations.

year: 2022

title: The cost-effectiveness of active surveillance compared to watchful waiting and radical prostatectomy for low risk localised prostate cancer

authors: Lao, Chunhuan

subjects: Science & Technology

abstract: Background
Radical prostatectomy is the most common treatment for localised prostate cancer in New Zealand. Active surveillance was introduced to prevent overtreatment and reduce costs while preserving the option of radical prostatectomy. This study aims to evaluate the cost-effectiveness of active surveillance compared to watchful waiting and radical prostatectomy.

Methods
Markov models were constructed to estimate the life-time cost-effectiveness of active surveillance compared to watchful waiting and radical prostatectomy for low risk localised prostate cancer patients aged 45–70 years, using national datasets in New Zealand and published studies including the SPCG-4 study. This study was from the perspective of the Ministry of Health in New Zealand.

Results
Radical prostatectomy is less costly than active surveillance in men aged 45–55 years with low risk localised prostate cancer, but more costly for men aged 60–70 years. Scenario analyses demonstrated significant uncertainty as to the most cost-effective option in all age groups because of the unavailability of good quality of life data for men under active surveillance. Uncertainties around the likelihood of having radical prostatectomy when managed with active surveillance also affect the cost-effectiveness of active surveillance against radical prostatectomy.

Conclusions
Active surveillance is less likely to be cost-effective compared to radical prostatectomy for younger men diagnosed with low risk localised prostate cancer. The cost-effectiveness of active surveillance compared to radical prostatectomy is critically dependent on the ‘trigger’ for radical prostatectomy and the quality of life in men on active surveillance. Research on the latter would be beneficial.

text: The cost-effectiveness of active surveillance compared to watchful waiting and radical prostatectomy for low risk localised prostate cancer Background
Radical prostatectomy is the most common treatment for localised prostate cancer in New Zealand. Active surveillance was introduced to prevent overtreatment and reduce costs while preserving the option of radical prostatectomy. This study aims to evaluate the cost-effectiveness of active surveillance compared to watchful waiting and radical prostatectomy.

Methods
Markov models were constructed to estimate the life-time cost-effectiveness of active surveillance compared to watchful waiting and radical prostatectomy for low risk localised prostate cancer patients aged 45–70 years, using national datasets in New Zealand and published studies including the SPCG-4 study. This study was from the perspective of the Ministry of Health in New Zealand.

Results
Radical prostatectomy is less costly than active surveillance in men aged 45–55 years with low risk localised prostate cancer, but more costly for men aged 60–70 years. Scenario analyses demonstrated significant uncertainty as to the most cost-effective option in all age groups because of the unavailability of good quality of life data for men under active surveillance. Uncertainties around the likelihood of having radical prostatectomy when managed with active surveillance also affect the cost-effectiveness of active surveillance against radical prostatectomy.

Conclusions
Active surveillance is less likely to be cost-effective compared to radical prostatectomy for younger men diagnosed with low risk localised prostate cancer. The cost-effectiveness of active surveillance compared to radical prostatectomy is critically dependent on the ‘trigger’ for radical prostatectomy and the quality of life in men on active surveillance. Research on the latter would be beneficial.

year: 2017

title: The Debate over 'Kai Tangata' (Maori Cannibalism): New Perspectives from the Correspondence of the Marists

authors: Jennings, William

subjects: cannibalism

abstract: French Marist missionaries working in New Zealand from 1838 sometimes mentioned Maori cannibalism in their correspondence. This article finds that the Marists considered cannibalism to be a cultural practice of minor interest, not a defining point of difference between Maori and Europeans. The article also finds some evidence of ritual cannibalism, but not of mass battlefield cannibalism or of the eating of people for food.

text: The Debate over 'Kai Tangata' (Maori Cannibalism): New Perspectives from the Correspondence of the Marists French Marist missionaries working in New Zealand from 1838 sometimes mentioned Maori cannibalism in their correspondence. This article finds that the Marists considered cannibalism to be a cultural practice of minor interest, not a defining point of difference between Maori and Europeans. The article also finds some evidence of ritual cannibalism, but not of mass battlefield cannibalism or of the eating of people for food.

year: 2011