title: Fish biomass in Taranaki streams in relation to sources and availability of energy

authors: Witton, Morgan Alexandra

abstract: Light and temperature are the principal drivers of ecosystem function influencing nutrient cycling, energy flows, and food web dynamics. Solar irradiance controls stream thermodynamics, and in-stream temperature governs the metabolic rate of stream biota.  The loss of riparian vegetation can lead to unpredictable changes in fish biomass due to variations in metabolic requirements and energy availability.  In New Zealand, unshaded pasture streams have been shown to support greater fish biomass, leading to questions about supply and demand synchronies and energy sources that support fish biomass under differing light and temperature regimes. 
This thesis focuses on the ecological processes in relation to the interactions among stream biota and their physical and chemical environment linking freshwater fish biomass, food web dynamics and energy availability. Using a variety of field assessments, I investigate food web dynamics and characterise energy flow with respect to land use and longitudinal riparian fragmentation in mountainous Taranaki streams, New Zealand. I further analyse the influence of alternative energy sources derived from terrestrial and marine environments and their subsidiary role in supporting fish biomass.
Fish densities and biomasses were five-fold greater in pasture than in forest streams and significant correlations were found with light intensity and water temperature (p < 0.05). Body mass to abundance (M-N) allometry was similar between land uses, but the effects of increased light and temperature in pasture streams likely resulted in increased abundance for the equivalent body sizes across the entire community.
Stable isotope analyses (SIA) revealed evidence for energetic and functional food web alterations, in response to land use. Changes in food sources were reflected by the transition in physical variables at the forest to pasture boundary. Here, non-predatory invertebrates showed a distinct food dominance transition between land uses, predominantly assimilating leaf litter (77%) in forest and shifting to periphyton (73%) in pasture. Periphyton biomass was significantly greater in pasture streams and was the most important food source for crayfish (Paranephrops planifrons), contributing 76% to crayfish diet in forest and 97% to crayfish diet in pasture. This highlights the importance of periphyton for energy transfer to higher trophic levels in streams. 
Fish showed a distinct dietary reliance on both crayfish and terrestrial invertebrates in both land uses. Unexpectedly, terrestrial invertebrate inputs were five-fold greater at pasture sites when compared to forest sites (p < 0.05). Since terrestrial invertebrates are an important food source consumed by New Zealand fish species, these terrestrially derived food sources may play a significant role in the observed fish biomass. This research highlighted the role of terrestrially derived invertebrates in providing a significant subsidiary energy source, irrespective of land use. 
Temperature plays a fundamental role in metabolic rates and energetic requirements of fish, emphasising the importance of temperature-driven changes in supply-demand synchronies. Importantly, summer water temperatures at pasture sites were closer to the thermal preferences of New Zealand fish species. This suggests that higher temperatures increase metabolic scope and food requirements. However, there must be sufficient food supply to compensate for rising metabolic demands of fish. 
On a longitudinal scale, Taranaki streams showed localised variations in energy utilisation in response to riparian fragmentation. Non-predatory invertebrates showed a food dominance transition back to allochthonous sources at lower sites, corresponding with greater riparian vegetation cover downstream.  Transitions in source dominance were also observed in longfin eel (Anguilla dieffenbachii) and shortfin eel (Anguilla australis) diets, where the proportional dominance shifted from aquatic invertebrates to terrestrial invertebrates at vegetated downstream sites.  These data were more reflective of recent conceptualised models derived from the Riverine Ecosystem Synthesis (RES), rather than the River Continuum Concept (RCC), with localised processes influencing pathways of energy transfer.
There is limited research on the contribution of marine-derived nitrogen (MDN) by diadromous New Zealand fish, which may provide an important subsidiary source of nutrients for stream production. MDN was detected in migratory inanga larvae (Galaxias maculatus) and shrimp (Paratya curvirostris), with these species showing comparable δ¹⁵N that reflected a period of marine residence. The incorporation of MDN was not expressed in the food web, however, most likely due to low densities of inanga and shrimp in the study reaches. High δ¹⁵N in inanga shows the potential for MDN to be incorporated into stream food webs where significant seasonal whitebait migrations occur.  
This research provides critical insight into the drivers behind fish biomass, highlighting temperature-driven supply and demand synchronies and the importance of resource availability in sustaining New Zealand fish populations.

text: Fish biomass in Taranaki streams in relation to sources and availability of energy Light and temperature are the principal drivers of ecosystem function influencing nutrient cycling, energy flows, and food web dynamics. Solar irradiance controls stream thermodynamics, and in-stream temperature governs the metabolic rate of stream biota.  The loss of riparian vegetation can lead to unpredictable changes in fish biomass due to variations in metabolic requirements and energy availability.  In New Zealand, unshaded pasture streams have been shown to support greater fish biomass, leading to questions about supply and demand synchronies and energy sources that support fish biomass under differing light and temperature regimes. 
This thesis focuses on the ecological processes in relation to the interactions among stream biota and their physical and chemical environment linking freshwater fish biomass, food web dynamics and energy availability. Using a variety of field assessments, I investigate food web dynamics and characterise energy flow with respect to land use and longitudinal riparian fragmentation in mountainous Taranaki streams, New Zealand. I further analyse the influence of alternative energy sources derived from terrestrial and marine environments and their subsidiary role in supporting fish biomass.
Fish densities and biomasses were five-fold greater in pasture than in forest streams and significant correlations were found with light intensity and water temperature (p < 0.05). Body mass to abundance (M-N) allometry was similar between land uses, but the effects of increased light and temperature in pasture streams likely resulted in increased abundance for the equivalent body sizes across the entire community.
Stable isotope analyses (SIA) revealed evidence for energetic and functional food web alterations, in response to land use. Changes in food sources were reflected by the transition in physical variables at the forest to pasture boundary. Here, non-predatory invertebrates showed a distinct food dominance transition between land uses, predominantly assimilating leaf litter (77%) in forest and shifting to periphyton (73%) in pasture. Periphyton biomass was significantly greater in pasture streams and was the most important food source for crayfish (Paranephrops planifrons), contributing 76% to crayfish diet in forest and 97% to crayfish diet in pasture. This highlights the importance of periphyton for energy transfer to higher trophic levels in streams. 
Fish showed a distinct dietary reliance on both crayfish and terrestrial invertebrates in both land uses. Unexpectedly, terrestrial invertebrate inputs were five-fold greater at pasture sites when compared to forest sites (p < 0.05). Since terrestrial invertebrates are an important food source consumed by New Zealand fish species, these terrestrially derived food sources may play a significant role in the observed fish biomass. This research highlighted the role of terrestrially derived invertebrates in providing a significant subsidiary energy source, irrespective of land use. 
Temperature plays a fundamental role in metabolic rates and energetic requirements of fish, emphasising the importance of temperature-driven changes in supply-demand synchronies. Importantly, summer water temperatures at pasture sites were closer to the thermal preferences of New Zealand fish species. This suggests that higher temperatures increase metabolic scope and food requirements. However, there must be sufficient food supply to compensate for rising metabolic demands of fish. 
On a longitudinal scale, Taranaki streams showed localised variations in energy utilisation in response to riparian fragmentation. Non-predatory invertebrates showed a food dominance transition back to allochthonous sources at lower sites, corresponding with greater riparian vegetation cover downstream.  Transitions in source dominance were also observed in longfin eel (Anguilla dieffenbachii) and shortfin eel (Anguilla australis) diets, where the proportional dominance shifted from aquatic invertebrates to terrestrial invertebrates at vegetated downstream sites.  These data were more reflective of recent conceptualised models derived from the Riverine Ecosystem Synthesis (RES), rather than the River Continuum Concept (RCC), with localised processes influencing pathways of energy transfer.
There is limited research on the contribution of marine-derived nitrogen (MDN) by diadromous New Zealand fish, which may provide an important subsidiary source of nutrients for stream production. MDN was detected in migratory inanga larvae (Galaxias maculatus) and shrimp (Paratya curvirostris), with these species showing comparable δ¹⁵N that reflected a period of marine residence. The incorporation of MDN was not expressed in the food web, however, most likely due to low densities of inanga and shrimp in the study reaches. High δ¹⁵N in inanga shows the potential for MDN to be incorporated into stream food webs where significant seasonal whitebait migrations occur.  
This research provides critical insight into the drivers behind fish biomass, highlighting temperature-driven supply and demand synchronies and the importance of resource availability in sustaining New Zealand fish populations.

year: 2022

title: Design and development of the trauma informed care beliefs scale-brief

authors: Beehag, Nathan

abstract: Background: Trauma informed care (TIC) practices have been developed to diminish the range of negative consequences associated with adverse childhood experiences (e.g., unemployment, welfare, incarceration, and medical and psychiatric treatment). They have been demonstrated to benefit young people, their carers, and child welfare staff. However, a gap that has been identified in this area is the absence of psychometrically sound TIC instruments, which has hindered the TIC literature in terms of transitioning to a more methodologically robust and data driven research area. Objective: The current study aimed to develop a psychometrically sound instrument (i.e., the TIC Belief Scale) that could assess the TIC beliefs of child welfare carers who reside with youth. Methods: Initially, 143 items were developed based on widely used TIC models. After a review by an expert panel of 10 experienced trauma practitioners, 85 items were retained and administered to a sample of 469 child welfare carers. The psychometric properties of the scale were investigated using Item Response theory (Rasch analyses). Results: Following analyses, a final scale of 13 items was accepted. The scale had good internal reliability (PSI = 0.77), showed evidence of unidimensionality, and there was no evidence of differential performance across sub-groups. Conclusions: The application of the Rasch model in this study provides support for the TIC Belief Scale as a psychometrically sound scale for measuring child welfare carers’ beliefs about TIC practices. An algorithm proposed here for converting ordinal to interval scoring increases the precision in understanding carers’ less favourable TIC beliefs.

text: Design and development of the trauma informed care beliefs scale-brief Background: Trauma informed care (TIC) practices have been developed to diminish the range of negative consequences associated with adverse childhood experiences (e.g., unemployment, welfare, incarceration, and medical and psychiatric treatment). They have been demonstrated to benefit young people, their carers, and child welfare staff. However, a gap that has been identified in this area is the absence of psychometrically sound TIC instruments, which has hindered the TIC literature in terms of transitioning to a more methodologically robust and data driven research area. Objective: The current study aimed to develop a psychometrically sound instrument (i.e., the TIC Belief Scale) that could assess the TIC beliefs of child welfare carers who reside with youth. Methods: Initially, 143 items were developed based on widely used TIC models. After a review by an expert panel of 10 experienced trauma practitioners, 85 items were retained and administered to a sample of 469 child welfare carers. The psychometric properties of the scale were investigated using Item Response theory (Rasch analyses). Results: Following analyses, a final scale of 13 items was accepted. The scale had good internal reliability (PSI = 0.77), showed evidence of unidimensionality, and there was no evidence of differential performance across sub-groups. Conclusions: The application of the Rasch model in this study provides support for the TIC Belief Scale as a psychometrically sound scale for measuring child welfare carers’ beliefs about TIC practices. An algorithm proposed here for converting ordinal to interval scoring increases the precision in understanding carers’ less favourable TIC beliefs.

year: 2023-10-01

title: Tatari, tautoko, tauawhi - Hei awhina tamariki ki te panui pukapuka: Some preliminary findings

authors: Glynn, Ted

subjects: Maori

abstract: The Tatari, Tautoko, Tauawhi reading tutoring procedures have been adapted from the procedures known as Pause, Prompt, Praise, first developed in Mangere in 1977. The first author offered the procedures as a koha at a Special Education Service hui at Poho o Rawiri in 1991. The second author took up the koha and obtained the support of kaumatua and kuia at Hairini marae Tauranga Moana, and the support of senior Maori staff of the Special Education Service National Office to produce a Maori language video and training booklet. This began an important bicultural journey through the processes of producing instructional materials and trailing and evaluating them in ways that are biculturally appropriate. This paper reports on that journey and presents some preliminary data on the implementation of Tatari, Tautoko, Tauawhi by seven tuakana - teina pairs in a bi-lingual classroom.

text: Tatari, tautoko, tauawhi - Hei awhina tamariki ki te panui pukapuka: Some preliminary findings The Tatari, Tautoko, Tauawhi reading tutoring procedures have been adapted from the procedures known as Pause, Prompt, Praise, first developed in Mangere in 1977. The first author offered the procedures as a koha at a Special Education Service hui at Poho o Rawiri in 1991. The second author took up the koha and obtained the support of kaumatua and kuia at Hairini marae Tauranga Moana, and the support of senior Maori staff of the Special Education Service National Office to produce a Maori language video and training booklet. This began an important bicultural journey through the processes of producing instructional materials and trailing and evaluating them in ways that are biculturally appropriate. This paper reports on that journey and presents some preliminary data on the implementation of Tatari, Tautoko, Tauawhi by seven tuakana - teina pairs in a bi-lingual classroom.

year: 1993