title: Alternative solutions for determining the spectral band weights for the subtractive resolution merge technique

authors: Ashraf, Muhammad Salman

subjects: data fusion

abstract: Data fusion using subtractive resolution merge (SRM) is limited because it currently requires fixed spectral band weights predetermined for particular sensors. This is problematic because there is an increasing availability of new and emerging sensors that have no predetermined band weights. There is also a need for fusion between sensors, which potentially requires a large number of sensor combinations and band weight calculations. This article demonstrates how the least sum of minimum absolute deviation (LAD, least absolute deviation) and ordinary least squares (OLS) regressions can calculate band weights for application in the SRM technique using QuickBird satellite and Vexcel aerial images. Both methods were effective in improving image details. The results of LAD and OLS are shown using qualitative and quantitative metrics and through unsupervised classification of freshwater habitat. OLS and LAD produce similar results; however, OLS is computationally simpler and easier to automate. The ability of the user to calculate their own scene specific band weights eliminates the dependence on predetermined sensor band weights. This research concludes that OLS band weight calculations should be integrated into the SRM technique to diversify its application.

text: Alternative solutions for determining the spectral band weights for the subtractive resolution merge technique Data fusion using subtractive resolution merge (SRM) is limited because it currently requires fixed spectral band weights predetermined for particular sensors. This is problematic because there is an increasing availability of new and emerging sensors that have no predetermined band weights. There is also a need for fusion between sensors, which potentially requires a large number of sensor combinations and band weight calculations. This article demonstrates how the least sum of minimum absolute deviation (LAD, least absolute deviation) and ordinary least squares (OLS) regressions can calculate band weights for application in the SRM technique using QuickBird satellite and Vexcel aerial images. Both methods were effective in improving image details. The results of LAD and OLS are shown using qualitative and quantitative metrics and through unsupervised classification of freshwater habitat. OLS and LAD produce similar results; however, OLS is computationally simpler and easier to automate. The ability of the user to calculate their own scene specific band weights eliminates the dependence on predetermined sensor band weights. This research concludes that OLS band weight calculations should be integrated into the SRM technique to diversify its application.

year: 2011

title: The ecology of ray species in an urbanised estuary: Seasonality, habitat use and pollutant exposure in Tauranga Harbour

authors: Cadwallader, Helen Frances

subjects: Marine ecology

abstract: Information about the movement, seasonality, and use of habitats by marine animals is vital for the mitigation of potential anthropogenic impacts. Ray species may be particularly at risk as they regularly inhabit coastal and estuarine waters. In New Zealand to-date, there has been scant research on the ecology of native ray species in estuarine habitats. In particular, there is a dearth of knowledge pertaining to the spatio-temporal use of the range of habitats within estuaries. The research detailed in this thesis was aimed at addressing the shortfall of information. First, a review of the methodology utilised in ascertaining movement behaviour in non-shark-like batoid elasmobranch species was carried out, as optimisation of tagging research technique underpins the ability to track behaviour of these organisms for long periods. Most studies reviewed adopted tag anchor techniques used on teleost fishes or sharks. As a consequence, the quality of information pertaining to ray habitat use and movements was, in many circumstances, poor. Synthesis of tag longevity using differing anchor methods and field and aquarium longevity experiments led to a recommendation of nylon umbrella darts for soft-skinned non-shark-like rays such as Bathytoshia brevicaudata. Second, seasonality in habitat use within the Tauranga Harbour system was examined using monthly counts of the feeding excavations of Myliobatis tenuicaudatus. This study expanded previous estimations of seasonality and feeding habitat choice in estuaries. It determined that temperature-mediated sinusoidal seasonal patterns in feeding behaviour over a period of 24 months, differed in magnitude and peak month across a range of spatial scales. This could suggest some form of sequential habitat use. Unlike previous studies, evidence of ray feeding was found year-round. This behavioural pattern has implications for calculations of sediment turnover and transport. Peak turnover estimates of ray origin from this study doubled previous estimated calculations. In addition, infaunal prey density, and locational aspects of estuary ‘sub-habitats’ characterised as various ‘zones’ as compared to ‘harbour basin’ habitats, were all found to be influential in the prediction of M. tenuicaudatus feeding activity. There were inverse seasonal differences in the relationship between densities of large infaunal bivalves (putative prey items) and ray feeding activity, suggesting that during some periods, other prey types (soft bodied organisms) may also be important. Suggestions are made that perceived predator risk and human disturbance may have a role in driving habitat preferences in addition to prey density. This study also found that natural mangrove fringe is preferred by M. tenuicaudatus for feeding habitat over areas of ‘fringe’ that had been trimmed to prevent mangrove spread. The implications of this are significant as there is a reduction in ideal feeding habitat with ongoing mangrove trimming regimes. Finally, quantification of metal body burden of M. tenuicaudatus identified low levels of some heavy metals in rays from Tauranga Harbour when compared to Porirua Harbour, and that metals in rays from the outer coast of the Bay of Plenty region were likely to be of volcanic origin. Significantly different metal assemblages of estuarine and offshore animals combined with feeding evidence found year-round in Tauranga Harbour, suggests a separation in populations between these areas. Overall however, it is clear that metal content in Tauranga Harbour rays lies below FZANZ levels of concern and the harbour may be classified as relatively unpolluted. However, the behavioural patterns of rays clearly lead them away from shallower sub estuary areas, that are known to be more contaminated by anthropogenic activity.
In conclusion, this thesis provides previously unknown information about the habits and ecology of the important estuarine mesopredator M. tenuicaudatus in the context of anthropogenic risk associated with an urbanised harbour ecosystem. The information will allow informed management of harbour activities and developmental options with regard to conservation of an ecologically important species.

text: The ecology of ray species in an urbanised estuary: Seasonality, habitat use and pollutant exposure in Tauranga Harbour Information about the movement, seasonality, and use of habitats by marine animals is vital for the mitigation of potential anthropogenic impacts. Ray species may be particularly at risk as they regularly inhabit coastal and estuarine waters. In New Zealand to-date, there has been scant research on the ecology of native ray species in estuarine habitats. In particular, there is a dearth of knowledge pertaining to the spatio-temporal use of the range of habitats within estuaries. The research detailed in this thesis was aimed at addressing the shortfall of information. First, a review of the methodology utilised in ascertaining movement behaviour in non-shark-like batoid elasmobranch species was carried out, as optimisation of tagging research technique underpins the ability to track behaviour of these organisms for long periods. Most studies reviewed adopted tag anchor techniques used on teleost fishes or sharks. As a consequence, the quality of information pertaining to ray habitat use and movements was, in many circumstances, poor. Synthesis of tag longevity using differing anchor methods and field and aquarium longevity experiments led to a recommendation of nylon umbrella darts for soft-skinned non-shark-like rays such as Bathytoshia brevicaudata. Second, seasonality in habitat use within the Tauranga Harbour system was examined using monthly counts of the feeding excavations of Myliobatis tenuicaudatus. This study expanded previous estimations of seasonality and feeding habitat choice in estuaries. It determined that temperature-mediated sinusoidal seasonal patterns in feeding behaviour over a period of 24 months, differed in magnitude and peak month across a range of spatial scales. This could suggest some form of sequential habitat use. Unlike previous studies, evidence of ray feeding was found year-round. This behavioural pattern has implications for calculations of sediment turnover and transport. Peak turnover estimates of ray origin from this study doubled previous estimated calculations. In addition, infaunal prey density, and locational aspects of estuary ‘sub-habitats’ characterised as various ‘zones’ as compared to ‘harbour basin’ habitats, were all found to be influential in the prediction of M. tenuicaudatus feeding activity. There were inverse seasonal differences in the relationship between densities of large infaunal bivalves (putative prey items) and ray feeding activity, suggesting that during some periods, other prey types (soft bodied organisms) may also be important. Suggestions are made that perceived predator risk and human disturbance may have a role in driving habitat preferences in addition to prey density. This study also found that natural mangrove fringe is preferred by M. tenuicaudatus for feeding habitat over areas of ‘fringe’ that had been trimmed to prevent mangrove spread. The implications of this are significant as there is a reduction in ideal feeding habitat with ongoing mangrove trimming regimes. Finally, quantification of metal body burden of M. tenuicaudatus identified low levels of some heavy metals in rays from Tauranga Harbour when compared to Porirua Harbour, and that metals in rays from the outer coast of the Bay of Plenty region were likely to be of volcanic origin. Significantly different metal assemblages of estuarine and offshore animals combined with feeding evidence found year-round in Tauranga Harbour, suggests a separation in populations between these areas. Overall however, it is clear that metal content in Tauranga Harbour rays lies below FZANZ levels of concern and the harbour may be classified as relatively unpolluted. However, the behavioural patterns of rays clearly lead them away from shallower sub estuary areas, that are known to be more contaminated by anthropogenic activity.
In conclusion, this thesis provides previously unknown information about the habits and ecology of the important estuarine mesopredator M. tenuicaudatus in the context of anthropogenic risk associated with an urbanised harbour ecosystem. The information will allow informed management of harbour activities and developmental options with regard to conservation of an ecologically important species.

year: 2020

title: Ati Ue: Te Aitanga a Tuoro

authors: James, Steven (Tipene) Robert

subjects: Ngati Whakaue

abstract: This thesis is based on the manuscripts of my tupuna Tuoro Akapita Pango that are held in a treasured whānau box. The manuscripts contain history and kōrero of Te Arawa written by multiple generations of the whānau Pango. Within this thesis I explore the value of inter-generational knowledge through considering what lies within these whānau manuscripts and taking the opportunity to discover more history about Ngāti Whakaue through a whānau lens. Researching these manuscripts enables reconnection of the past and the present; the reconnection between forgotten knowledge and whānau. 
Specifically, this thesis proposes a Ngāti Whakaue approach to engaging historical materials and research. It centres the voices of the people, such as the many family members involved within the process, as well as the box of writings and the many gems that hide within. Also, it asks what the manuscripts mean for the current descendants involved in the research. 
The research has been a means of reconnecting with the past to give relevance and context to the present. The objective is demonstrating the value of iwi-specific research methods so that whānau feel encouraged to embark on their own journey.

text: Ati Ue: Te Aitanga a Tuoro This thesis is based on the manuscripts of my tupuna Tuoro Akapita Pango that are held in a treasured whānau box. The manuscripts contain history and kōrero of Te Arawa written by multiple generations of the whānau Pango. Within this thesis I explore the value of inter-generational knowledge through considering what lies within these whānau manuscripts and taking the opportunity to discover more history about Ngāti Whakaue through a whānau lens. Researching these manuscripts enables reconnection of the past and the present; the reconnection between forgotten knowledge and whānau. 
Specifically, this thesis proposes a Ngāti Whakaue approach to engaging historical materials and research. It centres the voices of the people, such as the many family members involved within the process, as well as the box of writings and the many gems that hide within. Also, it asks what the manuscripts mean for the current descendants involved in the research. 
The research has been a means of reconnecting with the past to give relevance and context to the present. The objective is demonstrating the value of iwi-specific research methods so that whānau feel encouraged to embark on their own journey.

year: 2021