title: The change in the horizontal position of the dune toe and vegetation line on beaches within the Waikato Region

authors: Davies-Calway, Celeste Jade

subjects: dune toe

abstract: Beaches are highly variable landscapes that are constantly changing in response to a range of climatic variables. For example, local wind can cause the movement of sand across the beach and accretion, whilst storms that occur far from the beach create waves and surges which also changes the shape and morphology of the beach. The lower beach face is inundated for longer during a tidal cycle and therefore is subjected more often to wave action conversely, the upper part of the beach is inundated less often and therefore is less affected by wave energy. When storms occur, water levels are higher along the beach, waves are brought into contact with the upper beach face and erosion occurs. This erosion causes escarpment of the dune face and landward movement of the beach face, where sand is transported to offshore bars in the surf zone. Changes also occur during fair weather conditions where accretion occurs across the beach face and dune area and sand is transported back up onto the beach and sand dunes.

Beach morphology has traditionally been monitored using beach profiles, however new methods are emerging that provide more information with the potential for greater spatial and temporal data collection. In New Zealand the vegetation line and the position of the dune toe is often used as a proxy for the shoreline and setback distances are measured relative to this feature. Beach morphodynamics have been studied extensively but typical monitoring and predictive methods are not optimised to track and predict changes in the dune toe position. Beach profile surveys are the most common and reliable monitoring method used for monitoring beaches and they are used extensively throughout the world. Although beach profiles give valuable information on several different aspects of beach processes, they may not be the optimal method for tracking dune toe movement and there are other methods that might be more effective.

The aim of the research was to provide information to help optimise the monitoring and prediction of changes in the dune toe by determining: (i) the horizontal and vertical variation of the dune toe to establish how often the horizontal and vertical position of the sand dune toe changes, (ii) the alongshore variation of the dune toe along the beach length, (iii) what causes the changes in the dune toe, (iv) compare using the dune toe for beach monitoring with traditional beach monitoring methods, (v) testing different methods to measure the dune toe and vegetation line, (vi) predicting the dune toe in the future using a model. The main study sites for the research were Whangapoua Beach, Matarangi Beach, Buffalo Beach, Hot Water Beach and Tairua beach of eastern Coromandel Peninsula, and Ngarunui Beach, Raglan, where field surveys were conducted. An historical dataset of beach profiles from 20 Eastern Coromandel beaches were analysed for long term patterns. A new method for measuring dune toe using video analysis and a model for predicting the future dune toe changes was tested at Tairua Beach, Coromandel Peninsula.

The results show that, from the field survey of beach profiles, there was low variability at the dune toe compared with further down the beach. The range of distribution of the vegetation line was larger than the range of distribution for the dune toe and the dune toe was generally more seaward than the vegetation line. The vegetation line was generally not at the same location as the dune toe which has strong implications for using vegetation as a measure of dune movement. The alongshore dune toe underwent small changes throughout the survey period and there was alongshore variation of the dune toe, along with changes in the dune toe horizontal position and height of the dune toe throughout the year survey period, which was expected. Video analysis was shown to be a potential new technique for measuring the vegetation line which could be used for beach monitoring. A model was used to predict the change in the dune toe, and it predicted that there was no change in the dune toe between 1998 and 2011; however, the analysis of the imagery showed there were numerous occasions where water reached the dune toe and therefore erosion of the dune toe occurred.

text: The change in the horizontal position of the dune toe and vegetation line on beaches within the Waikato Region Beaches are highly variable landscapes that are constantly changing in response to a range of climatic variables. For example, local wind can cause the movement of sand across the beach and accretion, whilst storms that occur far from the beach create waves and surges which also changes the shape and morphology of the beach. The lower beach face is inundated for longer during a tidal cycle and therefore is subjected more often to wave action conversely, the upper part of the beach is inundated less often and therefore is less affected by wave energy. When storms occur, water levels are higher along the beach, waves are brought into contact with the upper beach face and erosion occurs. This erosion causes escarpment of the dune face and landward movement of the beach face, where sand is transported to offshore bars in the surf zone. Changes also occur during fair weather conditions where accretion occurs across the beach face and dune area and sand is transported back up onto the beach and sand dunes.

Beach morphology has traditionally been monitored using beach profiles, however new methods are emerging that provide more information with the potential for greater spatial and temporal data collection. In New Zealand the vegetation line and the position of the dune toe is often used as a proxy for the shoreline and setback distances are measured relative to this feature. Beach morphodynamics have been studied extensively but typical monitoring and predictive methods are not optimised to track and predict changes in the dune toe position. Beach profile surveys are the most common and reliable monitoring method used for monitoring beaches and they are used extensively throughout the world. Although beach profiles give valuable information on several different aspects of beach processes, they may not be the optimal method for tracking dune toe movement and there are other methods that might be more effective.

The aim of the research was to provide information to help optimise the monitoring and prediction of changes in the dune toe by determining: (i) the horizontal and vertical variation of the dune toe to establish how often the horizontal and vertical position of the sand dune toe changes, (ii) the alongshore variation of the dune toe along the beach length, (iii) what causes the changes in the dune toe, (iv) compare using the dune toe for beach monitoring with traditional beach monitoring methods, (v) testing different methods to measure the dune toe and vegetation line, (vi) predicting the dune toe in the future using a model. The main study sites for the research were Whangapoua Beach, Matarangi Beach, Buffalo Beach, Hot Water Beach and Tairua beach of eastern Coromandel Peninsula, and Ngarunui Beach, Raglan, where field surveys were conducted. An historical dataset of beach profiles from 20 Eastern Coromandel beaches were analysed for long term patterns. A new method for measuring dune toe using video analysis and a model for predicting the future dune toe changes was tested at Tairua Beach, Coromandel Peninsula.

The results show that, from the field survey of beach profiles, there was low variability at the dune toe compared with further down the beach. The range of distribution of the vegetation line was larger than the range of distribution for the dune toe and the dune toe was generally more seaward than the vegetation line. The vegetation line was generally not at the same location as the dune toe which has strong implications for using vegetation as a measure of dune movement. The alongshore dune toe underwent small changes throughout the survey period and there was alongshore variation of the dune toe, along with changes in the dune toe horizontal position and height of the dune toe throughout the year survey period, which was expected. Video analysis was shown to be a potential new technique for measuring the vegetation line which could be used for beach monitoring. A model was used to predict the change in the dune toe, and it predicted that there was no change in the dune toe between 1998 and 2011; however, the analysis of the imagery showed there were numerous occasions where water reached the dune toe and therefore erosion of the dune toe occurred.

year: 2020

title: Effects of copper sprays on microbial communities in kiwifruit orchard soils

authors: Dean, Fiona Patricia

abstract: There has been a significant increase in the use of antimicrobial copper sprays on kiwifruit orchards in the Western Bay of Plenty (WBOP) since the first outbreak of the bacterial vine disease Pseudomonas syringae pv. actinidiae (Psa-V) in 2010. Studies have revealed that an accumulation of copper in soil may adversely affect soil microorganisms, which are pivotal in essential soil functions such as nutrient assimilation.
The aim of this study was to determine whether or not the use of copper sprays on WBOP kiwifruit orchards has had detrimental effects on soil microorganisms and if this has resulted in changes to the structure of soil microbiological communities.
Soil was sampled from ten WBOP kiwifruit orchards with varying levels of copper but with similar physicochemical properties. These included five sets of two adjacent orchards, of which one was organic and the other conventional, and for which data was available on soil copper levels for 2011. 
DNA extracted from each soil was amplified with PCR and sequenced using Ion Torrent Sequencing technology. The resulting bacterial and archaeal sequences were binned into operational taxonomic units (OTUs) and the phylogeny of each was determined using the Ribosomal Database Project (RDP) Classifier. Soils were also analysed for a number of physicochemical properties including total, bioavailable and free ionic copper.
Non-metric Multidimensional Scaling (NMDS) and Multi-Response Permutation Procedures (MRPP) were used to examine dissimilarities between microbial communities in relation to soil copper levels, management practices and other physicochemical variables. Indicator species analyses were conducted on OTU abundance data to determine if particular OTUs were indicative of soils with the lowest and highest copper levels. Community data were also compared using a number of measures of diversity. Differences in physicochemical parameters between soils were analysed for significance using ANOVA and t-tests.
Results revealed that levels of total copper in soils have increased since 2011, with significant differences measured between each pair of orchards. Significant differences in soil microbial communities were also revealed, with pH identified as the main driver of community composition within and between orchards and differences between orchards were also largely explained by management practices. Relative abundances of Archaea were significantly higher in conventional orchards and in soils with the highest levels of copper. However, overall community dissimilarities were not found to be related to soil copper levels. Indicator species analysis revealed that soils with < 30 mg kg-1 of total copper had a greater abundance of Actinobacteria, whilst soils with > 60 mg kg-1 had a higher representation of Chlamydiae, Chloroflexi, and Thaumarchaeota. 
The conclusions of this research are that current copper levels in the study orchard soils have not significantly influenced soil microbial community composition and associated functions. However, the high number of influential variables confounded attempts at identifying differences due to copper alone. In addition, the lack of knowledge on the specific functions of individual taxa, make it very difficult to reveal the long-term implications of even subtle differences in community composition as a result of copper use.

text: Effects of copper sprays on microbial communities in kiwifruit orchard soils There has been a significant increase in the use of antimicrobial copper sprays on kiwifruit orchards in the Western Bay of Plenty (WBOP) since the first outbreak of the bacterial vine disease Pseudomonas syringae pv. actinidiae (Psa-V) in 2010. Studies have revealed that an accumulation of copper in soil may adversely affect soil microorganisms, which are pivotal in essential soil functions such as nutrient assimilation.
The aim of this study was to determine whether or not the use of copper sprays on WBOP kiwifruit orchards has had detrimental effects on soil microorganisms and if this has resulted in changes to the structure of soil microbiological communities.
Soil was sampled from ten WBOP kiwifruit orchards with varying levels of copper but with similar physicochemical properties. These included five sets of two adjacent orchards, of which one was organic and the other conventional, and for which data was available on soil copper levels for 2011. 
DNA extracted from each soil was amplified with PCR and sequenced using Ion Torrent Sequencing technology. The resulting bacterial and archaeal sequences were binned into operational taxonomic units (OTUs) and the phylogeny of each was determined using the Ribosomal Database Project (RDP) Classifier. Soils were also analysed for a number of physicochemical properties including total, bioavailable and free ionic copper.
Non-metric Multidimensional Scaling (NMDS) and Multi-Response Permutation Procedures (MRPP) were used to examine dissimilarities between microbial communities in relation to soil copper levels, management practices and other physicochemical variables. Indicator species analyses were conducted on OTU abundance data to determine if particular OTUs were indicative of soils with the lowest and highest copper levels. Community data were also compared using a number of measures of diversity. Differences in physicochemical parameters between soils were analysed for significance using ANOVA and t-tests.
Results revealed that levels of total copper in soils have increased since 2011, with significant differences measured between each pair of orchards. Significant differences in soil microbial communities were also revealed, with pH identified as the main driver of community composition within and between orchards and differences between orchards were also largely explained by management practices. Relative abundances of Archaea were significantly higher in conventional orchards and in soils with the highest levels of copper. However, overall community dissimilarities were not found to be related to soil copper levels. Indicator species analysis revealed that soils with < 30 mg kg-1 of total copper had a greater abundance of Actinobacteria, whilst soils with > 60 mg kg-1 had a higher representation of Chlamydiae, Chloroflexi, and Thaumarchaeota. 
The conclusions of this research are that current copper levels in the study orchard soils have not significantly influenced soil microbial community composition and associated functions. However, the high number of influential variables confounded attempts at identifying differences due to copper alone. In addition, the lack of knowledge on the specific functions of individual taxa, make it very difficult to reveal the long-term implications of even subtle differences in community composition as a result of copper use.

year: 2016

title: Social consequences of Tūhoe migration: Voices from home in Te Urewera

authors: Nikora, Linda Waimarie

subjects: age effects

abstract: A previous study by Nikora, Guerin, Rua & Te Awekotuku (2004) of the social consequences of Tūhoe moving to the Waikato region found employment and a tertiary education to be the primary motivators. Tūhoe ‘movers’ remained in contact with those who remain in Te Urewera and retained a wish to return to their tribal homelands if presented with work opportunities or upon retirement. Through 29 intensive conversational interviews conducted by Tūhoe community researchers with Tūhoe people we explored the social consequences of migration upon those who had remained ‘at home’. Most participants recognised and strongly supported ‘movers’ to better themselves and find successful futures but hoped that they would one day return. An emerging theme was an apparent age-distribution gap of people between about 20 and 50 years of age in the Tuhoe homelands. This is concerning for a number of reasons.  The ‘age gap’ may potentially bring about a) a lack of good role-models for younger children; b) a lack of people to help out with heavy work; c) a gap in people to sustain traditional teaching models for children, and d) a lack of qualified people in trades and professions. The age gap also means that a whole middle-aged group that in other communities might be contributing funds for capital expenditures are not present in the community.

text: Social consequences of Tūhoe migration: Voices from home in Te Urewera A previous study by Nikora, Guerin, Rua & Te Awekotuku (2004) of the social consequences of Tūhoe moving to the Waikato region found employment and a tertiary education to be the primary motivators. Tūhoe ‘movers’ remained in contact with those who remain in Te Urewera and retained a wish to return to their tribal homelands if presented with work opportunities or upon retirement. Through 29 intensive conversational interviews conducted by Tūhoe community researchers with Tūhoe people we explored the social consequences of migration upon those who had remained ‘at home’. Most participants recognised and strongly supported ‘movers’ to better themselves and find successful futures but hoped that they would one day return. An emerging theme was an apparent age-distribution gap of people between about 20 and 50 years of age in the Tuhoe homelands. This is concerning for a number of reasons.  The ‘age gap’ may potentially bring about a) a lack of good role-models for younger children; b) a lack of people to help out with heavy work; c) a gap in people to sustain traditional teaching models for children, and d) a lack of qualified people in trades and professions. The age gap also means that a whole middle-aged group that in other communities might be contributing funds for capital expenditures are not present in the community.

year: 2008