title: Long-term changes in Zooplankton community composition in North Island lakes: What are the drivers of change?

authors: Taylor, Amber

abstract: Zooplankton are an important component of freshwater ecosystems, forming a trophic bridge between primary producers and higher trophic levels. They are highly responsive to changes in their environment and have therefore been recognised as a useful tool for monitoring and assessing aquatic ecosystem health. However, long-term studies of changes in zooplankton communities are rare globally. Long-term studies of zooplankton composition are even more scarce within New Zealand. Past researches on New Zealand zooplankton have primarily focused on the seasonal variation of zooplankton composition, rather than long-term temporal changes, and have been undertaken over time periods of two years or less.
This study utilised zooplankton compositional data from past research papers (1950-1990) conducted within North Island, New Zealand lakes and data from two 2021 sampling events, to investigate long-term temporal zooplankton community composition change. A historical dataset was constructed by conducting a desktop investigation of past studies that included zooplankton species lists. Further, zooplankton samples were collected in 2021 using vertical net hauls from nine lakes within the Bay of Plenty and Waikato regions, using zooplankton nets with three different mesh sizes (37 μm, 75 μm and 100 μm). Species lists from the historical and 2021 samples were statistically analysed to identify changes in zooplankton diversity and community composition through time. The samples from each of the three nets were also analysed independently of the historical samples, to determine the influence of mesh size on zooplankton composition and species richness estimates from semi-quantitative samples.
Three major changes in zooplankton communities were evident over time. Firstly, high frequencies of the Holarctic cladoceran Daphnia galeata were found in the samples collected in 2021 yet were absent in samples taken prior to 1990. This result is consistent with the reported invasion of this species into New Zealand lakes since the early 1990s. Secondly, the cyclopoid copepod Macrocyclops albidus was not observed within the 2021 samples yet has been frequently present in species lists from the historical literature. This species has also not been commonly identified in recent research papers. Their low frequencies within the 2021 samples also coincides with increases in the importance of the D. galeata and cyclopoid copepod Mesocyclops australiensis in the 2021 samples and recent literature relative to historical datasets. Finally, there was an increase in the occurrence of many rotifer taxa within the 2021 samples compared to the historical samples. Interestingly, these taxa were largely deemed as an uncommon constituent of the plankton within New Zealand waters in the 1950s to 1970s. The increased importance of rotifer species within recent samples appeared to be a product of underestimation due to improper mesh selection by past researchers.
Analysis of the semi-quantitative data of the three zooplankton nets with different mesh sizes indicated that zooplankton composition and species richness using the 75 μm net was more representative of that collected by the 35 μm samples than the 100 μm samples. This result indicates that a 75 μm net would be adequate when comparing zooplankton results within a 35 μm net among the studied lakes. Species richness within the two smaller meshed nets were higher than the 100 μm net, indicating a net with mesh size of 100 μm and greater would result in an underestimation of zooplankton community composition and species richness.

text: Long-term changes in Zooplankton community composition in North Island lakes: What are the drivers of change? Zooplankton are an important component of freshwater ecosystems, forming a trophic bridge between primary producers and higher trophic levels. They are highly responsive to changes in their environment and have therefore been recognised as a useful tool for monitoring and assessing aquatic ecosystem health. However, long-term studies of changes in zooplankton communities are rare globally. Long-term studies of zooplankton composition are even more scarce within New Zealand. Past researches on New Zealand zooplankton have primarily focused on the seasonal variation of zooplankton composition, rather than long-term temporal changes, and have been undertaken over time periods of two years or less.
This study utilised zooplankton compositional data from past research papers (1950-1990) conducted within North Island, New Zealand lakes and data from two 2021 sampling events, to investigate long-term temporal zooplankton community composition change. A historical dataset was constructed by conducting a desktop investigation of past studies that included zooplankton species lists. Further, zooplankton samples were collected in 2021 using vertical net hauls from nine lakes within the Bay of Plenty and Waikato regions, using zooplankton nets with three different mesh sizes (37 μm, 75 μm and 100 μm). Species lists from the historical and 2021 samples were statistically analysed to identify changes in zooplankton diversity and community composition through time. The samples from each of the three nets were also analysed independently of the historical samples, to determine the influence of mesh size on zooplankton composition and species richness estimates from semi-quantitative samples.
Three major changes in zooplankton communities were evident over time. Firstly, high frequencies of the Holarctic cladoceran Daphnia galeata were found in the samples collected in 2021 yet were absent in samples taken prior to 1990. This result is consistent with the reported invasion of this species into New Zealand lakes since the early 1990s. Secondly, the cyclopoid copepod Macrocyclops albidus was not observed within the 2021 samples yet has been frequently present in species lists from the historical literature. This species has also not been commonly identified in recent research papers. Their low frequencies within the 2021 samples also coincides with increases in the importance of the D. galeata and cyclopoid copepod Mesocyclops australiensis in the 2021 samples and recent literature relative to historical datasets. Finally, there was an increase in the occurrence of many rotifer taxa within the 2021 samples compared to the historical samples. Interestingly, these taxa were largely deemed as an uncommon constituent of the plankton within New Zealand waters in the 1950s to 1970s. The increased importance of rotifer species within recent samples appeared to be a product of underestimation due to improper mesh selection by past researchers.
Analysis of the semi-quantitative data of the three zooplankton nets with different mesh sizes indicated that zooplankton composition and species richness using the 75 μm net was more representative of that collected by the 35 μm samples than the 100 μm samples. This result indicates that a 75 μm net would be adequate when comparing zooplankton results within a 35 μm net among the studied lakes. Species richness within the two smaller meshed nets were higher than the 100 μm net, indicating a net with mesh size of 100 μm and greater would result in an underestimation of zooplankton community composition and species richness.

year: 2023

title: Return on investment: Investigating managerial preferences for alternative return on investment reports

authors: Lys, Brendan John

subjects: ROI

abstract: Responses of 32 Officers and 1 Non Commissioned Officer, of the Royal New Zealand Navy, to three return on investment (ROI) training reports were investigated. The three report types were presented as a function of two ROI calculations: Critical Outcome Technique, and Utility Analysis - with Utility Analysis being used as the basis for two of the three reports. Participants were placed into one of three groups, each group consisted of 11 participants. Each participant group was presented with one of the three report types. Responses from participants were gained using a survey instrument for two constructs: perceived usefulness, and perceived understanding and clarity. The results of this study replicated the findings of previous studies in this area (i.e. Carson, Becker & Henderson, 1998; Macan & Foster, 2004). An analysis of quantitative data using Kruskal-Wallis statistical test failed to show significantly different perceptions of either perceived usefulness, or perceived understanding and clarity between the three groups. While the presented reports lacked high levels of support from participants, the findings of Latham and Whyte’s study (1994) are brought further into question (i.e. Cronshaw, 1997; Macan & Foster, 2004) as utility analysis based reports did not negatively influence participants on the uptake of the hypothetical training initiative. Content analysis of the qualitative data, revealed a number of potential factors which may have caused a lack of significance between report type preferences. Most critically these causes may not be limited to this this study alone, but may have implications for both previous and future studies into ROI acceptance.

text: Return on investment: Investigating managerial preferences for alternative return on investment reports Responses of 32 Officers and 1 Non Commissioned Officer, of the Royal New Zealand Navy, to three return on investment (ROI) training reports were investigated. The three report types were presented as a function of two ROI calculations: Critical Outcome Technique, and Utility Analysis - with Utility Analysis being used as the basis for two of the three reports. Participants were placed into one of three groups, each group consisted of 11 participants. Each participant group was presented with one of the three report types. Responses from participants were gained using a survey instrument for two constructs: perceived usefulness, and perceived understanding and clarity. The results of this study replicated the findings of previous studies in this area (i.e. Carson, Becker & Henderson, 1998; Macan & Foster, 2004). An analysis of quantitative data using Kruskal-Wallis statistical test failed to show significantly different perceptions of either perceived usefulness, or perceived understanding and clarity between the three groups. While the presented reports lacked high levels of support from participants, the findings of Latham and Whyte’s study (1994) are brought further into question (i.e. Cronshaw, 1997; Macan & Foster, 2004) as utility analysis based reports did not negatively influence participants on the uptake of the hypothetical training initiative. Content analysis of the qualitative data, revealed a number of potential factors which may have caused a lack of significance between report type preferences. Most critically these causes may not be limited to this this study alone, but may have implications for both previous and future studies into ROI acceptance.

year: 2011

title: Weaving Mana Wahine and Masi methodology: Centring the embodied experiences of young Māori and Pasifika wāhine in physical activity and everyday life

authors: Nemani, Mihi Joy

subjects: Aotearoa New Zealand

abstract: Young Indigenous Māori and Pasifika wāhine (women) in Aotearoa New Zealand (hereafter Aotearoa) have too often been framed as vulnerable, ‘at risk’ and problematic in the media, policy and research. This thesis moves beyond these deficit framings and uses an Indigenous feminist, strengths-based approach by centring the voices and lived experiences of young Māori and Pasifika wāhine who are agentic in their everyday lives, celebrate their strong brown bodies and are physically active. 

Being an Indigenous feminist early career researcher of Māori-Samoan ancestry, I intentionally weave Mana Wahine (Māori) and Masi (Pasifika) methodologies throughout all aspects of this research. Employing wānanga (focus group discussions), individual interviews and digital methods, I gather knowledge from a total of 31 young Māori and Pasifika wāhine residing in two low socio-economic urban regions (Porirua and South Auckland) in Te Ika-a-Maui, the North Island of Aotearoa. Centring their voices and lived experiences, I examine how the young wāhine embrace and weave their intersectional identities with culture, body image and physical activity. 

This is a PhD with publication. It begins with an introductory chapter and a literature review chapter that locates the project in the context of Aotearoa and the local and international literature. In the methods chapter, which is a published article, I focus on the importance of creating culturally safe and supportive spaces for young wāhine to participate in research that feels meaningful to them. The empirical chapters are presented in three different manuscripts. Chapter Four contains a manuscript (currently under review) that focuses on the intersectional identities of the young wāhine. It is structured using three key themes, including 1) ethnic and cultural identities, 2) navigating, and 3) how they embrace cultural pride, particularly through family values, customs and responsibilities. Chapter Five is a published manuscript that explores body image through an intersectional Indigenous feminist lens. This publication examines cultural perspectives that influence their views on body image and provides insights into how the young wāhine navigate body image stereotypes. Chapter six is the final empirical manuscript (currently under review) that evaluates the motivations the young wāhine have for participation in physical activity. It examines the types of activities they enjoy and provides insights into how and why they use cultural knowledge as a motivator for participation.

This research contributes to international literature conducted with, for and by Indigenous feminist scholars on young women’s identities, body image and physical activity. It responds to the limited academic scholarship that explores the lived experiences of young Māori and Pasifika wāhine in Aotearoa and their nuanced cultural knowledge of their bodies. In so doing, this research offers insights and new ways of understanding the complex lives of young Māori and Pasifika wāhine, and highlights the importance of intersectional approaches and localized Indigenous methods that listen to, and amplify the voices of young wāhine.

text: Weaving Mana Wahine and Masi methodology: Centring the embodied experiences of young Māori and Pasifika wāhine in physical activity and everyday life Young Indigenous Māori and Pasifika wāhine (women) in Aotearoa New Zealand (hereafter Aotearoa) have too often been framed as vulnerable, ‘at risk’ and problematic in the media, policy and research. This thesis moves beyond these deficit framings and uses an Indigenous feminist, strengths-based approach by centring the voices and lived experiences of young Māori and Pasifika wāhine who are agentic in their everyday lives, celebrate their strong brown bodies and are physically active. 

Being an Indigenous feminist early career researcher of Māori-Samoan ancestry, I intentionally weave Mana Wahine (Māori) and Masi (Pasifika) methodologies throughout all aspects of this research. Employing wānanga (focus group discussions), individual interviews and digital methods, I gather knowledge from a total of 31 young Māori and Pasifika wāhine residing in two low socio-economic urban regions (Porirua and South Auckland) in Te Ika-a-Maui, the North Island of Aotearoa. Centring their voices and lived experiences, I examine how the young wāhine embrace and weave their intersectional identities with culture, body image and physical activity. 

This is a PhD with publication. It begins with an introductory chapter and a literature review chapter that locates the project in the context of Aotearoa and the local and international literature. In the methods chapter, which is a published article, I focus on the importance of creating culturally safe and supportive spaces for young wāhine to participate in research that feels meaningful to them. The empirical chapters are presented in three different manuscripts. Chapter Four contains a manuscript (currently under review) that focuses on the intersectional identities of the young wāhine. It is structured using three key themes, including 1) ethnic and cultural identities, 2) navigating, and 3) how they embrace cultural pride, particularly through family values, customs and responsibilities. Chapter Five is a published manuscript that explores body image through an intersectional Indigenous feminist lens. This publication examines cultural perspectives that influence their views on body image and provides insights into how the young wāhine navigate body image stereotypes. Chapter six is the final empirical manuscript (currently under review) that evaluates the motivations the young wāhine have for participation in physical activity. It examines the types of activities they enjoy and provides insights into how and why they use cultural knowledge as a motivator for participation.

This research contributes to international literature conducted with, for and by Indigenous feminist scholars on young women’s identities, body image and physical activity. It responds to the limited academic scholarship that explores the lived experiences of young Māori and Pasifika wāhine in Aotearoa and their nuanced cultural knowledge of their bodies. In so doing, this research offers insights and new ways of understanding the complex lives of young Māori and Pasifika wāhine, and highlights the importance of intersectional approaches and localized Indigenous methods that listen to, and amplify the voices of young wāhine.

year: 2024-10-20