title: Molecular insights into ecosystem health: Comparative characterisation of dietary ecology and spatial biodiversity patterns through DNA metabarcoding of threatened predator species in Aotearoa New Zealand

authors: Stanners, Ashleigh

subjects: eDNA

abstract: Predator species play critical ecological roles, influencing food web dynamics, regulating prey populations, and reflecting the health of their surrounding ecosystems. In Aotearoa New Zealand, many threatened predators inhabit environments under pressure from habitat modification, invasive species, and climate change. Understanding their dietary ecology and the biodiversity of their habitats is essential for effective conservation management. Environmental DNA (eDNA) metabarcoding, which uses genetic material shed into the environment to identify taxa, offers a non-invasive and highly sensitive approach to investigating both diet and broader biodiversity patterns. My thesis aimed to compare the dietary ecology and incidental biodiversity detection of two threatened predators inhabiting contrasting ecosystems, and to evaluate how ecological context shapes the information recovered through molecular analyses.

The first analysis (Chapter 2) examined the diet of the long-tailed bat (Chalinolobus tuberculatus) across multiple roosting locations within a single plantation forest over the summer season. This was the first study of its kind at this scale for the species, generating an unprecedented molecular dataset. Metabarcoding revealed a diet dominated by arthropods from multiple insect orders, encompassing both native and introduced taxa. Differences linked to reproductive status suggested shifts in prey choice driven by energetic demands, while variation between pre- and post-harvest periods indicated sensitivity to forestry management cycles. These results highlight both the potential role of this species in regulating introduced insects and its value as a bioindicator in managed forest systems.

The second analysis (Chapter 3) investigated little blue penguins (Eudyptula minor) from an island breeding colony within a sheltered harbour, focusing on both dietary and non-diet biodiversity signals. While direct dietary resolution was limited, eDNA recovered a rich record of terrestrial and nearshore taxa, reflecting seasonal and spatial variation in colony-adjacent biodiversity. These patterns were potentially influenced by seasonal ocean productivity, prey migration, microhabitat heterogeneity, and anthropogenic disturbance, demonstrating the capacity of faecal eDNA to capture wider ecosystem information.

Together, these studies demonstrate that predator faecal metabarcoding can provide complementary insights into species ecology and environmental condition, even when direct dietary resolution is constrained. By integrating trophic and incidental biodiversity data, this research contributes molecular baselines for long-term monitoring, enables the characterisation of hard-to-study or cryptic species that are otherwise difficult to observe directly, underscores the influence of ecological context on eDNA recovery, and supports the use of non-invasive molecular tools to inform evidence-based management and the conservation of threatened species and their habitats in Aotearoa New Zealand.

text: Molecular insights into ecosystem health: Comparative characterisation of dietary ecology and spatial biodiversity patterns through DNA metabarcoding of threatened predator species in Aotearoa New Zealand Predator species play critical ecological roles, influencing food web dynamics, regulating prey populations, and reflecting the health of their surrounding ecosystems. In Aotearoa New Zealand, many threatened predators inhabit environments under pressure from habitat modification, invasive species, and climate change. Understanding their dietary ecology and the biodiversity of their habitats is essential for effective conservation management. Environmental DNA (eDNA) metabarcoding, which uses genetic material shed into the environment to identify taxa, offers a non-invasive and highly sensitive approach to investigating both diet and broader biodiversity patterns. My thesis aimed to compare the dietary ecology and incidental biodiversity detection of two threatened predators inhabiting contrasting ecosystems, and to evaluate how ecological context shapes the information recovered through molecular analyses.

The first analysis (Chapter 2) examined the diet of the long-tailed bat (Chalinolobus tuberculatus) across multiple roosting locations within a single plantation forest over the summer season. This was the first study of its kind at this scale for the species, generating an unprecedented molecular dataset. Metabarcoding revealed a diet dominated by arthropods from multiple insect orders, encompassing both native and introduced taxa. Differences linked to reproductive status suggested shifts in prey choice driven by energetic demands, while variation between pre- and post-harvest periods indicated sensitivity to forestry management cycles. These results highlight both the potential role of this species in regulating introduced insects and its value as a bioindicator in managed forest systems.

The second analysis (Chapter 3) investigated little blue penguins (Eudyptula minor) from an island breeding colony within a sheltered harbour, focusing on both dietary and non-diet biodiversity signals. While direct dietary resolution was limited, eDNA recovered a rich record of terrestrial and nearshore taxa, reflecting seasonal and spatial variation in colony-adjacent biodiversity. These patterns were potentially influenced by seasonal ocean productivity, prey migration, microhabitat heterogeneity, and anthropogenic disturbance, demonstrating the capacity of faecal eDNA to capture wider ecosystem information.

Together, these studies demonstrate that predator faecal metabarcoding can provide complementary insights into species ecology and environmental condition, even when direct dietary resolution is constrained. By integrating trophic and incidental biodiversity data, this research contributes molecular baselines for long-term monitoring, enables the characterisation of hard-to-study or cryptic species that are otherwise difficult to observe directly, underscores the influence of ecological context on eDNA recovery, and supports the use of non-invasive molecular tools to inform evidence-based management and the conservation of threatened species and their habitats in Aotearoa New Zealand.

year: 2025

title: Development and Characterisation of Plasmonic Devices for Sensing Applications

authors: Sedoglavich, Nemanya

subjects: Plasmonic

abstract: In recent years, discoveries and advances that utilise nano-scale (10^-9m) structures and associated phenomena have led to a number of entirely new areas of research in the fields of physics, chemistry, biology, and materials science. The photonic field of plasmonics is the study of light interaction with nanometer-scaled metal-dielectric features, which gives rise to a variety of phenomena, including surface plasmon resonance, localised surface plasmon resonance, and metal enhanced fluorescence. The focus of this thesis is on the development and characterisation of nanophotonic devices, which utilise plasmonic phenomena and have potential for sensor applications.
During the course of this research a surface plasmon resonance analysis platform was devised, which utilises the gold grating of commercially available compact disks as the sensing substrate. This measurement method offers a high resolution refractive index analysis of gases and surface chemistry and is capable of analysing a large number of samples by scanning over the entire disk surface. The system implements a method of phase-polarisation contrast to improve the sensing performance. It enhances signal detection through redistributing the residual p-polarised waves, which have been strongly absorbed by the surface plasmon resonance substrate/sensor. This effectively lowers the reflected light intensity at the surface plasmon resonance minimum. The scheme results in the deepening of the intensity minimum to below 3.5% reflection and the enhancement of resonance to non-resonance contrast by up to 14 times, and thereby increasing sensitivity.
A range of new nanophotonic structures have been modelled, developed, fabricated, and characterised, which we call wavelength and polarisation selective polariton generators (SPGs). These polarisation-sensitive structures combine a tuneable plasmon resonator and a subwavelength aperture to selectively generate and transmit polaritons of a desired wavelength through a central nanohole. Individual SPGs permit modulation of transmission intensity, with calculated enhanced optical transmission (ratio of output to input flux) of up to 10 and up to 4-fold measured amplitude modulation. The paired SPGs gave rise to multiple spectrally discrete transmission peaks which, when modulated, provide a multi-state operation in a single device. The measured amplitude modulation was up to 10-fold. For the linearly continuous SPG, by controlling the polarisation as a tuning variable, it selectively generated and transported polaritons of a desired wavelength. It exhibited a spectral shift of 40 nm over the full range of polarisation angles. The modelled enhanced optical transmission was calculated to be up to 17.2. An instrument was developed for measuring and characterising light transmission through single nanoholes, nanohole arrays, and other complex structures. The operational characteristics of these elements show close agreement between model predictions and experimental data. It also demonstrates new designs of plasmonic structures which utilise selective behaviour based on the polarisation of incident light.

text: Development and Characterisation of Plasmonic Devices for Sensing Applications In recent years, discoveries and advances that utilise nano-scale (10^-9m) structures and associated phenomena have led to a number of entirely new areas of research in the fields of physics, chemistry, biology, and materials science. The photonic field of plasmonics is the study of light interaction with nanometer-scaled metal-dielectric features, which gives rise to a variety of phenomena, including surface plasmon resonance, localised surface plasmon resonance, and metal enhanced fluorescence. The focus of this thesis is on the development and characterisation of nanophotonic devices, which utilise plasmonic phenomena and have potential for sensor applications.
During the course of this research a surface plasmon resonance analysis platform was devised, which utilises the gold grating of commercially available compact disks as the sensing substrate. This measurement method offers a high resolution refractive index analysis of gases and surface chemistry and is capable of analysing a large number of samples by scanning over the entire disk surface. The system implements a method of phase-polarisation contrast to improve the sensing performance. It enhances signal detection through redistributing the residual p-polarised waves, which have been strongly absorbed by the surface plasmon resonance substrate/sensor. This effectively lowers the reflected light intensity at the surface plasmon resonance minimum. The scheme results in the deepening of the intensity minimum to below 3.5% reflection and the enhancement of resonance to non-resonance contrast by up to 14 times, and thereby increasing sensitivity.
A range of new nanophotonic structures have been modelled, developed, fabricated, and characterised, which we call wavelength and polarisation selective polariton generators (SPGs). These polarisation-sensitive structures combine a tuneable plasmon resonator and a subwavelength aperture to selectively generate and transmit polaritons of a desired wavelength through a central nanohole. Individual SPGs permit modulation of transmission intensity, with calculated enhanced optical transmission (ratio of output to input flux) of up to 10 and up to 4-fold measured amplitude modulation. The paired SPGs gave rise to multiple spectrally discrete transmission peaks which, when modulated, provide a multi-state operation in a single device. The measured amplitude modulation was up to 10-fold. For the linearly continuous SPG, by controlling the polarisation as a tuning variable, it selectively generated and transported polaritons of a desired wavelength. It exhibited a spectral shift of 40 nm over the full range of polarisation angles. The modelled enhanced optical transmission was calculated to be up to 17.2. An instrument was developed for measuring and characterising light transmission through single nanoholes, nanohole arrays, and other complex structures. The operational characteristics of these elements show close agreement between model predictions and experimental data. It also demonstrates new designs of plasmonic structures which utilise selective behaviour based on the polarisation of incident light.

year: 2009

title: Ngā tai e rere nei i waho o Mauao

authors: Ngahuia, Dixon

subjects: Waiata Māori

abstract: "I te ao o ngā tūpuna he maha ngā kaupapa o taua wā i mau ki rō waiata, e whakaata mai ana i ngā kōrero-ā-iwi, ngā taukumekume i waenganui Māori, Pākehā, i waenganui hoki i ngā Māori anō. Nā wai hoki ka puta mai ngā herenga ki waenganui i tēnā iwi, i tēnā hapū, ka whakahoahoa tēnā iwi ki tēnā, te mutunga mai ka whānau ake ngā rōpū hou hei wānanga i ngā kaupapa i manawapātia. I pērā anō hoki ngā iwi o Tauranga Moana, ka huri atu ki tēnei iwi, ki tēnā hei huarahi tautoko āwhina mai i aua kaupapa nei. Ko ngā pupurihanga o ēnei taonga tuku iho e whakaahua mai ana i ngā kaupapa i waenganui i te ao Māori i aua wā, mō te iwi, mō te tangata kotahi rānei. Mā ēnei hoki kitea atu ai tā rātou titiro ki te ao i aua wā. 

He whiringa kōrero tēnei pepa mō tētehi waiata a Ngāi-TeRangi e whakamōhio ake ana i tētehi taukumekume i waenganui i a rāua ko Ngāti Kahungunu. Ka kitea i roto i ngā kōrero ka puta ngā huarahi whakapā atu ai ki tēnā iwi, hapū i waenganui, i waho atu rānei o Ngāi-TeRangi hei āwhina mai i te pupuri mana. Arā anō hoki te whakanui i ēnei momo waiata, ōna mana me te mātauranga Māori e pupū ake ana i konei. 

The waiata of our tūpuna Māori (Māori ancestors) capture in verse many issues and topics that were of significance at the time they were composed. They provide us with snapshots of iwi histories, including accounts of battles between Māori and Pākehā and between Māori and Māori. They tell us of alliances formed and reformed between tribes and hapū and of the reasons for these alliances. We see how the alignment and realignment of kin loyalties related to the issues of the day. Tauranga Moana iwi were not immune to such activities: tribal loyalties were chameleon-like, many alliances being pursued in relation to common interests. The ‘oral mapping’ of these local narratives that we find in waiata provides an illustration of topics relevant to individuals and to iwi: personal and collective statements about the ‘order’ of their day. They provide us with an insight into our ancestors’ ‘ways of seeing the world’. Above all, they are fundamental to the illustration and preservation of Māori knowledge. 
 
This paper presents an analysis of a Ngāi-TeRangi waiata tangi (lament) which relates to activities linking the iwi in a political stance against Ngāti Kahungunu. What is demonstrated is the intricate network of iwi and hapū involvement, within and without Ngāi-TeRangi, in the quest for honour. What is also demonstrated is the importance of waiata as significant literary achievements, as oral treasures."

text: Ngā tai e rere nei i waho o Mauao "I te ao o ngā tūpuna he maha ngā kaupapa o taua wā i mau ki rō waiata, e whakaata mai ana i ngā kōrero-ā-iwi, ngā taukumekume i waenganui Māori, Pākehā, i waenganui hoki i ngā Māori anō. Nā wai hoki ka puta mai ngā herenga ki waenganui i tēnā iwi, i tēnā hapū, ka whakahoahoa tēnā iwi ki tēnā, te mutunga mai ka whānau ake ngā rōpū hou hei wānanga i ngā kaupapa i manawapātia. I pērā anō hoki ngā iwi o Tauranga Moana, ka huri atu ki tēnei iwi, ki tēnā hei huarahi tautoko āwhina mai i aua kaupapa nei. Ko ngā pupurihanga o ēnei taonga tuku iho e whakaahua mai ana i ngā kaupapa i waenganui i te ao Māori i aua wā, mō te iwi, mō te tangata kotahi rānei. Mā ēnei hoki kitea atu ai tā rātou titiro ki te ao i aua wā. 

He whiringa kōrero tēnei pepa mō tētehi waiata a Ngāi-TeRangi e whakamōhio ake ana i tētehi taukumekume i waenganui i a rāua ko Ngāti Kahungunu. Ka kitea i roto i ngā kōrero ka puta ngā huarahi whakapā atu ai ki tēnā iwi, hapū i waenganui, i waho atu rānei o Ngāi-TeRangi hei āwhina mai i te pupuri mana. Arā anō hoki te whakanui i ēnei momo waiata, ōna mana me te mātauranga Māori e pupū ake ana i konei. 

The waiata of our tūpuna Māori (Māori ancestors) capture in verse many issues and topics that were of significance at the time they were composed. They provide us with snapshots of iwi histories, including accounts of battles between Māori and Pākehā and between Māori and Māori. They tell us of alliances formed and reformed between tribes and hapū and of the reasons for these alliances. We see how the alignment and realignment of kin loyalties related to the issues of the day. Tauranga Moana iwi were not immune to such activities: tribal loyalties were chameleon-like, many alliances being pursued in relation to common interests. The ‘oral mapping’ of these local narratives that we find in waiata provides an illustration of topics relevant to individuals and to iwi: personal and collective statements about the ‘order’ of their day. They provide us with an insight into our ancestors’ ‘ways of seeing the world’. Above all, they are fundamental to the illustration and preservation of Māori knowledge. 
 
This paper presents an analysis of a Ngāi-TeRangi waiata tangi (lament) which relates to activities linking the iwi in a political stance against Ngāti Kahungunu. What is demonstrated is the intricate network of iwi and hapū involvement, within and without Ngāi-TeRangi, in the quest for honour. What is also demonstrated is the importance of waiata as significant literary achievements, as oral treasures."

year: 2002-09