title: Are zooplankton invasions in constructed waters facilitated by simple communities?

authors: Parkes, Samantha Maree

subjects: biological invasions

abstract: Aim Constructed water bodies (e.g. water supply and hydroelectricity dams, ornamental ponds) are invaded at faster rates than natural waters, but the mechanisms that lead to this pattern are uncertain. We aimed to determine whether constructed lakes have lower zooplankton species richness or differ in species composition relative to natural waters, which might allow them to be invaded more readily. 

Location North Island, New Zealand. 

Methods Sediment cores were collected from 23 natural and 23 constructed lakes, ponds and reservoirs. Zooplankton diapausing eggs were hatched from sediments to assess species composition and richness. 

Results Average species richness between natural and constructed water bodies was not significantly different. Stepwise linear regression indicated latitude and maximum depth were significant predictors of species richness in natural waters (P = 0.002 and 0.016, respectively). No significant predictors were elucidated for constructed waters. Species in natural waters consisted mainly of planktonic species, while assemblages in constructed waters were more varied, comprising of more littoral and benthic species, and included many species recorded from only single water bodies. Canonical correspondence analysis indicated that trophic state explained the greatest proportion of variation in species composition of natural waters (P = 0.002). Distance to nearest water body and number of water bodies within a 20 km radius (i.e. opportunity) explained the greatest proportion in constructed waters (P = 0.040 and 0.038, respectively). 

Main conclusions Natural and constructed waters had similar species richness per water body, but community composition varied between them. The core group of species found in natural waters are better adapted to pelagic conditions, and may therefore be better at reducing establishment rates of new arrivals than assemblages in constructed water bodies, which had more varied assemblages. Our study suggests that manipulating new water bodies, so that they develop mature communities faster, may reduce establishment rates of non-indigenous species.

text: Are zooplankton invasions in constructed waters facilitated by simple communities? Aim Constructed water bodies (e.g. water supply and hydroelectricity dams, ornamental ponds) are invaded at faster rates than natural waters, but the mechanisms that lead to this pattern are uncertain. We aimed to determine whether constructed lakes have lower zooplankton species richness or differ in species composition relative to natural waters, which might allow them to be invaded more readily. 

Location North Island, New Zealand. 

Methods Sediment cores were collected from 23 natural and 23 constructed lakes, ponds and reservoirs. Zooplankton diapausing eggs were hatched from sediments to assess species composition and richness. 

Results Average species richness between natural and constructed water bodies was not significantly different. Stepwise linear regression indicated latitude and maximum depth were significant predictors of species richness in natural waters (P = 0.002 and 0.016, respectively). No significant predictors were elucidated for constructed waters. Species in natural waters consisted mainly of planktonic species, while assemblages in constructed waters were more varied, comprising of more littoral and benthic species, and included many species recorded from only single water bodies. Canonical correspondence analysis indicated that trophic state explained the greatest proportion of variation in species composition of natural waters (P = 0.002). Distance to nearest water body and number of water bodies within a 20 km radius (i.e. opportunity) explained the greatest proportion in constructed waters (P = 0.040 and 0.038, respectively). 

Main conclusions Natural and constructed waters had similar species richness per water body, but community composition varied between them. The core group of species found in natural waters are better adapted to pelagic conditions, and may therefore be better at reducing establishment rates of new arrivals than assemblages in constructed water bodies, which had more varied assemblages. Our study suggests that manipulating new water bodies, so that they develop mature communities faster, may reduce establishment rates of non-indigenous species.

year: 2012

title: 'Is This Student Voice?'  Students and Teachers Re-negotiate Power through Governance Partnerships in the Classroom

authors: Nelson, Emily Jane

subjects: student voice

abstract: A change in status for students to position them influentially as educational decision-makers with teachers is identified as a key dimension of student voice research and pedagogy.  Despite over 30 years of student voice research and pedagogical practice, this change in student status remains problematic.  Accountability agendas associated with neo-liberalism intermingle with student voice ideals contributing to contradictory purposes for, and in some cases diminutive instantiations of, student voice research and practice.  This tension often renders student influence illusory, fleeting or difficult to sustain.  Greater theorising of the power dynamics at work in enacting ongoing student influence in pedagogical and curriculum design, that also takes account of expectations and demands on teachers’ practice, is called for.  This research contributes to this challenge.  
Three teachers and their Year Seven and Eight students within one intermediate school collaborated across a three-cycle action research project to identify and utilise student perceptions of effective teaching and engagement as a basis for co-constructing responsive and reciprocal pedagogy as governance partners.  The teachers met regularly to plan and reflect on aspects of enacting the teacher/student governance partnerships in their classes, collaborating to ensure that aspects of teacher voice were addressed in the process of enacting student voice.  A student research group of 12 students drawn from the three participating classes provided ongoing reflection and insight into classroom power dynamics as the research unfolded. 
Teacher/student ‘governance partnerships’ were enacted as a way to maximise student influence within classroom-based pedagogy and curriculum decision-making.  A power analytic framework was developed to theorise the relationships between voice and power by mashing Lukes’ three-dimensional theory of faced power with Foucault’s micro-physics of power and theories of discourse and discourse analysis.  
Three findings emerged from this research.  Firstly the research established that the vantage point from which student voice practice was experienced influenced how that practice was perceived.  Teachers were more certain that their co-constructive action research work with students represented student voice in action because the students demonstrated behaviour teachers identified with student voice.  Participatory strategies enacted within the action research meant that student talk and reflection about their learning and themselves as learners increased.  Teachers gained valuable insight into their students as learners as well as the efficacy of their teaching from this student talk.  As teachers came to increasingly trust their students’ contributions, students’ thinking came to influence teachers’ thinking and the student voice curriculum in the three classrooms.  
Students from their vantage point were more ambivalent in their evaluation of these same actions. Although they appreciated having a say in deciding aspects of the classroom programme, they identified pedagogical decision-making as a clear responsibility for teachers who they perceived were professionally trained for this responsibility.  
Secondly, the power analytic frame developed for the research illuminated visible and less visible aspects of how power dynamics influenced teachers’ and students’ action as governance partners.  Persistent tensions between co-construction and accountability agendas meant that teachers and students were constrained in their student voice action by school expectations and macro accountability demands.  However they were able to negotiate ways to address these constraints, largely in ways that accommodated rather than challenged them.
Thirdly the shift in power dynamics between teachers and students in the research classrooms generated spaces conducive to the emergence of a student discourse on student voice.  Students identified the importance of knowing and being known as learners by their peers, rather than being motivated to establish influential relationships with teachers.  This student-student collaboration theme pushes back against adult-centric student voice discourses focused on increasing the influence of students in conventionally teacher-dominated decision-making domains.  
Implications from this research suggest that although building student influence in classrooms as a means to elevate their status as governance partners with teachers is necessary, student voice practice and research needs to look beyond the classroom to bring taken-for-granted elements of school culture expectations, and how these constrain classroom possibilities for action, into the student voice agenda.  Teachers and researchers need also to consider how their conceptions of student voice are imposed within the context of compulsory classwork on students.  The power analytic frame developed for this research may assist students, teachers, policy makers and researchers to keep the problematic nature of student voice in schools to the forefront as they plan, implement and critically reflect on classroom and school student voice initiatives to scaffold student influence within the educative process.

text: 'Is This Student Voice?'  Students and Teachers Re-negotiate Power through Governance Partnerships in the Classroom A change in status for students to position them influentially as educational decision-makers with teachers is identified as a key dimension of student voice research and pedagogy.  Despite over 30 years of student voice research and pedagogical practice, this change in student status remains problematic.  Accountability agendas associated with neo-liberalism intermingle with student voice ideals contributing to contradictory purposes for, and in some cases diminutive instantiations of, student voice research and practice.  This tension often renders student influence illusory, fleeting or difficult to sustain.  Greater theorising of the power dynamics at work in enacting ongoing student influence in pedagogical and curriculum design, that also takes account of expectations and demands on teachers’ practice, is called for.  This research contributes to this challenge.  
Three teachers and their Year Seven and Eight students within one intermediate school collaborated across a three-cycle action research project to identify and utilise student perceptions of effective teaching and engagement as a basis for co-constructing responsive and reciprocal pedagogy as governance partners.  The teachers met regularly to plan and reflect on aspects of enacting the teacher/student governance partnerships in their classes, collaborating to ensure that aspects of teacher voice were addressed in the process of enacting student voice.  A student research group of 12 students drawn from the three participating classes provided ongoing reflection and insight into classroom power dynamics as the research unfolded. 
Teacher/student ‘governance partnerships’ were enacted as a way to maximise student influence within classroom-based pedagogy and curriculum decision-making.  A power analytic framework was developed to theorise the relationships between voice and power by mashing Lukes’ three-dimensional theory of faced power with Foucault’s micro-physics of power and theories of discourse and discourse analysis.  
Three findings emerged from this research.  Firstly the research established that the vantage point from which student voice practice was experienced influenced how that practice was perceived.  Teachers were more certain that their co-constructive action research work with students represented student voice in action because the students demonstrated behaviour teachers identified with student voice.  Participatory strategies enacted within the action research meant that student talk and reflection about their learning and themselves as learners increased.  Teachers gained valuable insight into their students as learners as well as the efficacy of their teaching from this student talk.  As teachers came to increasingly trust their students’ contributions, students’ thinking came to influence teachers’ thinking and the student voice curriculum in the three classrooms.  
Students from their vantage point were more ambivalent in their evaluation of these same actions. Although they appreciated having a say in deciding aspects of the classroom programme, they identified pedagogical decision-making as a clear responsibility for teachers who they perceived were professionally trained for this responsibility.  
Secondly, the power analytic frame developed for the research illuminated visible and less visible aspects of how power dynamics influenced teachers’ and students’ action as governance partners.  Persistent tensions between co-construction and accountability agendas meant that teachers and students were constrained in their student voice action by school expectations and macro accountability demands.  However they were able to negotiate ways to address these constraints, largely in ways that accommodated rather than challenged them.
Thirdly the shift in power dynamics between teachers and students in the research classrooms generated spaces conducive to the emergence of a student discourse on student voice.  Students identified the importance of knowing and being known as learners by their peers, rather than being motivated to establish influential relationships with teachers.  This student-student collaboration theme pushes back against adult-centric student voice discourses focused on increasing the influence of students in conventionally teacher-dominated decision-making domains.  
Implications from this research suggest that although building student influence in classrooms as a means to elevate their status as governance partners with teachers is necessary, student voice practice and research needs to look beyond the classroom to bring taken-for-granted elements of school culture expectations, and how these constrain classroom possibilities for action, into the student voice agenda.  Teachers and researchers need also to consider how their conceptions of student voice are imposed within the context of compulsory classwork on students.  The power analytic frame developed for this research may assist students, teachers, policy makers and researchers to keep the problematic nature of student voice in schools to the forefront as they plan, implement and critically reflect on classroom and school student voice initiatives to scaffold student influence within the educative process.

year: 2014

title: Mycobacterium tuberculosis strains in New Zealand: phylogeny and structural biology

authors: Claire Vignette, Mulholland

subjects: tuberculosis

abstract: Mycobacterium tuberculosis is an obligate human pathogen and is the primary causative agent of tuberculosis. New Zealand has a relatively low incidence of tuberculosis disease, however, Māori (the indigenous people of New Zealand) and Pacific People are disproportionally affected. Molecular typing shows that approximately two-thirds of M. tuberculosis isolates from New Zealand-born patients can be assigned to clusters of related strains. The largest M. tuberculosis cluster in New Zealand is known as the ‘Rangipo’ cluster and is predominantly found in Māori. This strain has been the source of several tuberculosis outbreaks over the last 30 years and anecdotal evidence suggests it may be particularly virulent. Two other large clusters, known as the ‘Southern Cross’ and ‘Otara’ clusters, most commonly occur in Pacific People.
Here, whole genome sequencing, phylogenetics and structural biology were used to investigate evolutionary origins and functional consequences of genomic diversity in New Zealand M. tuberculosis clusters, with a particular focus on the Rangipo strain. Analysis of Rangipo strain non-synonymous single nucleotide polymorphisms (nsSNPs) identified bacterial genetic factors that may contribute to the high transmissibility of this strain. The F420-dependent oxidoreductase Rv2893 harbours a Rangipo-specific G72S mutation encoded by a nsSNP. H37Rv and Rangipo Rv2893 structures were solved and show the effect of this G72S mutation. Binding of the F420 cofactor was confirmed and characterised. SNP analyses also guided the optimisation of a diagnostic assay for rapid Rangipo strain classification at low cost and with high discriminatory power. Phylogenetic analyses revealed the Rangipo and Otara clusters belong to a larger M.tuberculosis clade of French/European origin that is also prevalent in indigenous populations in Canada. Molecular dating indicates dispersal of this clade to the South Pacific was driven by expanding European trade networks in the early 19th century and identifies host factors that have contributed to the dispersal and expansion of the Rangipo and Otara strains.
Overall, these results show that relatively recent changes in host ecology have likely played a crucial role in driving the success of the Rangipo strain in New Zealand and point to bacterial genetic factors that may influence its virulence and thereby also contribute to its prevalence.

text: Mycobacterium tuberculosis strains in New Zealand: phylogeny and structural biology Mycobacterium tuberculosis is an obligate human pathogen and is the primary causative agent of tuberculosis. New Zealand has a relatively low incidence of tuberculosis disease, however, Māori (the indigenous people of New Zealand) and Pacific People are disproportionally affected. Molecular typing shows that approximately two-thirds of M. tuberculosis isolates from New Zealand-born patients can be assigned to clusters of related strains. The largest M. tuberculosis cluster in New Zealand is known as the ‘Rangipo’ cluster and is predominantly found in Māori. This strain has been the source of several tuberculosis outbreaks over the last 30 years and anecdotal evidence suggests it may be particularly virulent. Two other large clusters, known as the ‘Southern Cross’ and ‘Otara’ clusters, most commonly occur in Pacific People.
Here, whole genome sequencing, phylogenetics and structural biology were used to investigate evolutionary origins and functional consequences of genomic diversity in New Zealand M. tuberculosis clusters, with a particular focus on the Rangipo strain. Analysis of Rangipo strain non-synonymous single nucleotide polymorphisms (nsSNPs) identified bacterial genetic factors that may contribute to the high transmissibility of this strain. The F420-dependent oxidoreductase Rv2893 harbours a Rangipo-specific G72S mutation encoded by a nsSNP. H37Rv and Rangipo Rv2893 structures were solved and show the effect of this G72S mutation. Binding of the F420 cofactor was confirmed and characterised. SNP analyses also guided the optimisation of a diagnostic assay for rapid Rangipo strain classification at low cost and with high discriminatory power. Phylogenetic analyses revealed the Rangipo and Otara clusters belong to a larger M.tuberculosis clade of French/European origin that is also prevalent in indigenous populations in Canada. Molecular dating indicates dispersal of this clade to the South Pacific was driven by expanding European trade networks in the early 19th century and identifies host factors that have contributed to the dispersal and expansion of the Rangipo and Otara strains.
Overall, these results show that relatively recent changes in host ecology have likely played a crucial role in driving the success of the Rangipo strain in New Zealand and point to bacterial genetic factors that may influence its virulence and thereby also contribute to its prevalence.

year: 2019