title: The ecology of the lucerne flea, Sminthurus viridis, in the South-Auckland/Waikato area

authors: Dentener, Peter Roeland

abstract: Lucerne flea, Sminthurus viridis L., is an annual pest in pastures in the Auckland/Waikato area. It damages legumes, particularly white clover, from late autumn until early summer, with a peak in infestation in spring. No research into the seasonality of the lucerne flea (LF) has been done in New Zealand. It was therefore decided to study the bionomics and population dynamics of LF, and aspects related to the damage, caused by LF.

The study showed that the life cycle of LF consisted of three nymphal instars, one adult male and three adult female instars with the males being smaller and lighter in weight than the females. The population of LF built up steadily from March or April onwards to reach a peak in numbers in October or November after which the numbers declined to a low level and LF were only present as diapause eggs. Rainfall in March and April played an important role in the hatching of the diapause eggs and influenced the survival of the first instar larvae. The accumulated temperature (°D) above a zero development threshold of 4 °C determined the number of generations of LF per year, with five generations in 1982 and four in 1983 in Huntly. Shutting up a paddock for hay production as well as the consecutive cutting of the hay influenced the number of LF in the field. Population dynamic studies of LF showed that LF populations had overlapping stages of development as well as overlapping generations during the study period.  Examination of the data with methods, equivalent to the k-factor analysis, showed that LF populations were prone to great changes in number at the beginning of the immature stage of the life cycle of the males and the end of the life cycle of the females, but fairly stable at the time that sexual maturity was reached. The locomotory activity of LF took place during the day and night and all growth stages were active. No statistically significant relationship could be found between the locomotory activity and temperature or rainfall. The mite, Bdellodes lapidaria, a predator of LF, was found in the study sites in Huntly but their numbers were so low that no control effect on LF could be established. Feeding trials showed that adult female LF ate significantly more than adult male LF, and that the feeding rate was highest at 15 and 20 °C and a photophase of 12 and 16 hours light. Other results suggested that some feeding activity would also occur at night. Severe damage by LF in the field reduced the leaf surface area of white clover plants by up to 40 % during this study, and most severe damage was observed in October and November. Observations in the field and the laboratory established that LF is a wasteful feeder.

text: The ecology of the lucerne flea, Sminthurus viridis, in the South-Auckland/Waikato area Lucerne flea, Sminthurus viridis L., is an annual pest in pastures in the Auckland/Waikato area. It damages legumes, particularly white clover, from late autumn until early summer, with a peak in infestation in spring. No research into the seasonality of the lucerne flea (LF) has been done in New Zealand. It was therefore decided to study the bionomics and population dynamics of LF, and aspects related to the damage, caused by LF.

The study showed that the life cycle of LF consisted of three nymphal instars, one adult male and three adult female instars with the males being smaller and lighter in weight than the females. The population of LF built up steadily from March or April onwards to reach a peak in numbers in October or November after which the numbers declined to a low level and LF were only present as diapause eggs. Rainfall in March and April played an important role in the hatching of the diapause eggs and influenced the survival of the first instar larvae. The accumulated temperature (°D) above a zero development threshold of 4 °C determined the number of generations of LF per year, with five generations in 1982 and four in 1983 in Huntly. Shutting up a paddock for hay production as well as the consecutive cutting of the hay influenced the number of LF in the field. Population dynamic studies of LF showed that LF populations had overlapping stages of development as well as overlapping generations during the study period.  Examination of the data with methods, equivalent to the k-factor analysis, showed that LF populations were prone to great changes in number at the beginning of the immature stage of the life cycle of the males and the end of the life cycle of the females, but fairly stable at the time that sexual maturity was reached. The locomotory activity of LF took place during the day and night and all growth stages were active. No statistically significant relationship could be found between the locomotory activity and temperature or rainfall. The mite, Bdellodes lapidaria, a predator of LF, was found in the study sites in Huntly but their numbers were so low that no control effect on LF could be established. Feeding trials showed that adult female LF ate significantly more than adult male LF, and that the feeding rate was highest at 15 and 20 °C and a photophase of 12 and 16 hours light. Other results suggested that some feeding activity would also occur at night. Severe damage by LF in the field reduced the leaf surface area of white clover plants by up to 40 % during this study, and most severe damage was observed in October and November. Observations in the field and the laboratory established that LF is a wasteful feeder.

year: 1985

title: Students' transitions into initial teacher education: Understanding barriers and enablers through an ecological lens

authors: Amundsen, Diana Leigh

abstract: This paper presents a small-scale qualitative investigation which explored early first-year transition experiences of pre-service teacher students. The study took place in one university in Aotearoa New Zealand, involving 24 students and three co-researchers from a Faculty of Education. Perceptions of students’ transition experiences were gathered through an essay task six weeks into the first semester; data were analysed using Bronfenbrenner’s (1979) ecological theory to identify barriers and enablers related to students’ transition experiences in various contexts. Diverse transitions accounts of ‘becoming a pre-service teacher student’ were analysed as being complex and intertwined with historical, social, cultural and political elements. These findings have implications for providers and educators of pre-service teacher programmes. Purposeful application of Bronfenbrenner’s theory to identify, name and understand how various transition barriers and enablers impact wellbeing and resilience could open up a more visible, shared and understood transition experience.

text: Students' transitions into initial teacher education: Understanding barriers and enablers through an ecological lens This paper presents a small-scale qualitative investigation which explored early first-year transition experiences of pre-service teacher students. The study took place in one university in Aotearoa New Zealand, involving 24 students and three co-researchers from a Faculty of Education. Perceptions of students’ transition experiences were gathered through an essay task six weeks into the first semester; data were analysed using Bronfenbrenner’s (1979) ecological theory to identify barriers and enablers related to students’ transition experiences in various contexts. Diverse transitions accounts of ‘becoming a pre-service teacher student’ were analysed as being complex and intertwined with historical, social, cultural and political elements. These findings have implications for providers and educators of pre-service teacher programmes. Purposeful application of Bronfenbrenner’s theory to identify, name and understand how various transition barriers and enablers impact wellbeing and resilience could open up a more visible, shared and understood transition experience.

year: 2021

title: Microplastics in the marine environment: Sediment contaminant and bioaccumulation rates in bivalves within the Bay of Plenty

authors: Lewis, Anita

subjects: Microplastic

abstract: Microplastic pollution is recognised as a significant anthropogenic issue in coastal ecosystems around the world. The accumulation of microplastics in coastal environments causes both direct and indirect effects on these already vulnerable ecosystems. Limited information was available of the scale of microplastic pollution across New Zealand, including the Bay of Plenty. To enable a greater understanding of microplastic accumulation in sediment and bioaccumulation in bivalves sampling  within the Bay of Plenty area was conducted.
The presence of  microplastic particles was investigated from sediment and shellfish samples collected across the Bay of Plenty, from Waihī Beach in the West, to Ōpōtiki in the East. Three species of shellfish were collected that differed in their functional feeding modes (filter feeder vs deposit feeder): tuangi (cockle: Austrovenus stuchburyi), hanikura (wedge shell: Macomona liliana), and tuatua (surf clam: Paphies subtriangulata). Microplastic particles from sediment and bivalves were separated from the sediment and shellfish samples in the laboratory and identified using visual light stereomicroscopy. Microplastic particles were identified and quantified into three categories: fragments, fibres, and films. 
Significant numbers of fibres, as well as some fragments and films were found to be present in the sediment throughout all sampling locations. The highest density of microplastic particles in sediment (up to 11,087.9 per m²) were observed at sites that were closed to municipal sewage outfalls and populated areas, and the lowest densities were observed at Matakana Island (63 particles per m²). Sites in Ōhiwa Harbour showed an average of 504.6 particles per m² at the high tide zone and 477.6 particles per m² at the intertidal zone in the sediment. Ohiwa Harbour showed similar levels of microplastic accumulation in sediment compared to Tauranga Harbour. However, higher levels of microplastic particles were found in the sediment at open coast sites.
All shellfish sampled had at least one microplastic particle found in their tissues. The highest number of microplastics in shellfish were found in the wedge shell (23 particles), with the least from the cockles (1). Statistical analysis reveal that the deep burrowing deposit feeder (Macomona liliana) demonstrated an elevated amount of microplastic particles ingested relative to the shallow burrowing suspension feeding cockle (Austrovenus stutchburyi). A notable amount of microplastic particles were also found at all sampling locations for the culturally important tuatua (Paphies subtriangulata). However, comparing all three bivalve species, the deposit feeding M. liliana, ingested higher amounts than both the A. stutchburyi and P. subtriangulata, which could be related to their different functional feeding modes in the marine environment. This research provides baseline information to assess the extent of microplastic pollution in sediments and the potential for bioaccumulation in bivalve species with differentiated feeding modes and functional roles in the marine environment. 
The problem with microplastics is a global emerging contaminant. Preventing the problem of plastic wastes in New Zealand will require change across all aspects of society, along with policy regulations to mitigate the issue of microplastic pollution.

text: Microplastics in the marine environment: Sediment contaminant and bioaccumulation rates in bivalves within the Bay of Plenty Microplastic pollution is recognised as a significant anthropogenic issue in coastal ecosystems around the world. The accumulation of microplastics in coastal environments causes both direct and indirect effects on these already vulnerable ecosystems. Limited information was available of the scale of microplastic pollution across New Zealand, including the Bay of Plenty. To enable a greater understanding of microplastic accumulation in sediment and bioaccumulation in bivalves sampling  within the Bay of Plenty area was conducted.
The presence of  microplastic particles was investigated from sediment and shellfish samples collected across the Bay of Plenty, from Waihī Beach in the West, to Ōpōtiki in the East. Three species of shellfish were collected that differed in their functional feeding modes (filter feeder vs deposit feeder): tuangi (cockle: Austrovenus stuchburyi), hanikura (wedge shell: Macomona liliana), and tuatua (surf clam: Paphies subtriangulata). Microplastic particles from sediment and bivalves were separated from the sediment and shellfish samples in the laboratory and identified using visual light stereomicroscopy. Microplastic particles were identified and quantified into three categories: fragments, fibres, and films. 
Significant numbers of fibres, as well as some fragments and films were found to be present in the sediment throughout all sampling locations. The highest density of microplastic particles in sediment (up to 11,087.9 per m²) were observed at sites that were closed to municipal sewage outfalls and populated areas, and the lowest densities were observed at Matakana Island (63 particles per m²). Sites in Ōhiwa Harbour showed an average of 504.6 particles per m² at the high tide zone and 477.6 particles per m² at the intertidal zone in the sediment. Ohiwa Harbour showed similar levels of microplastic accumulation in sediment compared to Tauranga Harbour. However, higher levels of microplastic particles were found in the sediment at open coast sites.
All shellfish sampled had at least one microplastic particle found in their tissues. The highest number of microplastics in shellfish were found in the wedge shell (23 particles), with the least from the cockles (1). Statistical analysis reveal that the deep burrowing deposit feeder (Macomona liliana) demonstrated an elevated amount of microplastic particles ingested relative to the shallow burrowing suspension feeding cockle (Austrovenus stutchburyi). A notable amount of microplastic particles were also found at all sampling locations for the culturally important tuatua (Paphies subtriangulata). However, comparing all three bivalve species, the deposit feeding M. liliana, ingested higher amounts than both the A. stutchburyi and P. subtriangulata, which could be related to their different functional feeding modes in the marine environment. This research provides baseline information to assess the extent of microplastic pollution in sediments and the potential for bioaccumulation in bivalve species with differentiated feeding modes and functional roles in the marine environment. 
The problem with microplastics is a global emerging contaminant. Preventing the problem of plastic wastes in New Zealand will require change across all aspects of society, along with policy regulations to mitigate the issue of microplastic pollution.

year: 2021