title: New Zealand’s indigenous forests – their status and drivers of change

authors: Allen, Robert

abstract: New Zealand’s remaining indigenous forests and shrublands are of immense cultural, environmental, and economic significance. A representative plot-based sample of these forests and shrublands has recently allowed an unbiased depiction of their composition
and structure. This is necessary for international reporting, performance assessment and management prioritisation. Their composition, structure, and function are driven by a diverse array of factors, many of which are complexly interrelated. The imprint of disturbances is pervasive and it is necessary to understand disturbances to interpret human-related impacts. For example, understanding impacts of exotic browsing mammals is only possible within a context of forest ecosystem development and tree demographic processes. There are now extensive areas of shrublands successional to forest, often composed of mixtures of indigenous and exotic species. These shrublands expand the pportunities for ecosystem services from, for example, carbon sequestration to water quality. An increasing area of indigenous forests and shrublands are managed for distinctive Māori aspirations that include sustainable use.

text: New Zealand’s indigenous forests – their status and drivers of change New Zealand’s remaining indigenous forests and shrublands are of immense cultural, environmental, and economic significance. A representative plot-based sample of these forests and shrublands has recently allowed an unbiased depiction of their composition
and structure. This is necessary for international reporting, performance assessment and management prioritisation. Their composition, structure, and function are driven by a diverse array of factors, many of which are complexly interrelated. The imprint of disturbances is pervasive and it is necessary to understand disturbances to interpret human-related impacts. For example, understanding impacts of exotic browsing mammals is only possible within a context of forest ecosystem development and tree demographic processes. There are now extensive areas of shrublands successional to forest, often composed of mixtures of indigenous and exotic species. These shrublands expand the pportunities for ecosystem services from, for example, carbon sequestration to water quality. An increasing area of indigenous forests and shrublands are managed for distinctive Māori aspirations that include sustainable use.

year: 2015

title: The cultural and ecological health of the Tokaanu Stream

authors: Eastwood, Kevin

abstract: Freshwater ecosystems worldwide face increasing threats from human activities like land development and altered flow regimes. These pressures, along with climate change, jeopardize water quality and quantity. Despite these challenges, effective management can improve water quality and habitat, thus sustaining biodiversity and ecosystem services.
Lake Taupō, Aotearoa New Zealand’s largest freshwater lake, holds immense significance for the local iwi, Ngāti Tūwharetoa. The Tokaanu Stream is a tributary of Lake Taupō that was once considered a premier fly-fishing spot. However, the stream has been severely impacted by the Tongariro Power Scheme, which required it to be bisected and channelized to accommodate the Tokaanu tailrace. Coupled with land-use changes in the catchment, these alterations have caused the local hapū, Ngāti Kurauia, who have mana whenua over the lower stream, to raise concerns about its ecological and cultural degradation. To address this problem, I developed a cultural monitoring framework (CMF) in collaboration with Ngāti Kurauia, alongside conventional stream monitoring, at six sites in the lower Tokaanu Stream.
The bespoke CMF was developed through kōrero and wānanga (discussions and workshops) with Ngāti Kurauia. This participatory approach resulted in a CMF with 16 attributes covering vegetation, birdlife, water quality, pollution, engineering, and substrate. Regular assessments revealed a longitudinal decline in stream condition from the most upstream site (Site 1) to the most downstream (Site 6). The state of Site 3 was identified as the most desirable, whilst Site 5 was the most degraded.
Alongside the CMF, I assessed stream health using conventional scientific measures. This monitoring also showed a longitudinal decline in stream ecosystem health moving downstream. Water quality worsened, with indicator bacteria increasing from 45 to 190 CFU/100 ml and total ammoniacal nitrogen from 0.029 to 0.125 g/m3 over the 4 km segment. Deposited fine sediment cover was high, increasing from 69% cover at Site 1 to 83% at Site 6. Cellulose degradation rates (a functional indicator) were diminished at Sites 5 and 6 in both years, even with warming from geothermal springs. Macroinvertebrate communities, monitored in 2023 and 2024, initially showed a linear decline moving downstream in 2023. However, in-stream remediation in early 2024, undertaken by a private contractor, significantly improved macroinvertebrate indicators at impacted sites (Sites 4-6).
The challenges facing the Tokaanu Stream are complex, stemming from geothermal inputs, urbanisation, upstream agriculture, and channelization. Declining water quality may be linked to faulty sewage infrastructure in Tokaanu Village. The stream's diversion includes a tailrace spillway that prevents larger downstream flows, potentially reducing scouring events crucial for natural sediment dynamics. These changes have significant ecological and cultural ramifications for Ngāti Kurauia.
To better understand and address these issues, I argue for an additional downstream State of the Environment (SOE) monitoring site. The current site, near the upstream spring, fails to capture the full impact of catchment inputs, including diffuse pollution from Tokaanu Village and altered sediment dynamics from the diversion. An additional SOE site, coupled with the findings of my thesis, would provide crucial knowledge to support efforts in restoring the Tokaanu Stream's ecological health and the mana of Ngāti Kurauia.

text: The cultural and ecological health of the Tokaanu Stream Freshwater ecosystems worldwide face increasing threats from human activities like land development and altered flow regimes. These pressures, along with climate change, jeopardize water quality and quantity. Despite these challenges, effective management can improve water quality and habitat, thus sustaining biodiversity and ecosystem services.
Lake Taupō, Aotearoa New Zealand’s largest freshwater lake, holds immense significance for the local iwi, Ngāti Tūwharetoa. The Tokaanu Stream is a tributary of Lake Taupō that was once considered a premier fly-fishing spot. However, the stream has been severely impacted by the Tongariro Power Scheme, which required it to be bisected and channelized to accommodate the Tokaanu tailrace. Coupled with land-use changes in the catchment, these alterations have caused the local hapū, Ngāti Kurauia, who have mana whenua over the lower stream, to raise concerns about its ecological and cultural degradation. To address this problem, I developed a cultural monitoring framework (CMF) in collaboration with Ngāti Kurauia, alongside conventional stream monitoring, at six sites in the lower Tokaanu Stream.
The bespoke CMF was developed through kōrero and wānanga (discussions and workshops) with Ngāti Kurauia. This participatory approach resulted in a CMF with 16 attributes covering vegetation, birdlife, water quality, pollution, engineering, and substrate. Regular assessments revealed a longitudinal decline in stream condition from the most upstream site (Site 1) to the most downstream (Site 6). The state of Site 3 was identified as the most desirable, whilst Site 5 was the most degraded.
Alongside the CMF, I assessed stream health using conventional scientific measures. This monitoring also showed a longitudinal decline in stream ecosystem health moving downstream. Water quality worsened, with indicator bacteria increasing from 45 to 190 CFU/100 ml and total ammoniacal nitrogen from 0.029 to 0.125 g/m3 over the 4 km segment. Deposited fine sediment cover was high, increasing from 69% cover at Site 1 to 83% at Site 6. Cellulose degradation rates (a functional indicator) were diminished at Sites 5 and 6 in both years, even with warming from geothermal springs. Macroinvertebrate communities, monitored in 2023 and 2024, initially showed a linear decline moving downstream in 2023. However, in-stream remediation in early 2024, undertaken by a private contractor, significantly improved macroinvertebrate indicators at impacted sites (Sites 4-6).
The challenges facing the Tokaanu Stream are complex, stemming from geothermal inputs, urbanisation, upstream agriculture, and channelization. Declining water quality may be linked to faulty sewage infrastructure in Tokaanu Village. The stream's diversion includes a tailrace spillway that prevents larger downstream flows, potentially reducing scouring events crucial for natural sediment dynamics. These changes have significant ecological and cultural ramifications for Ngāti Kurauia.
To better understand and address these issues, I argue for an additional downstream State of the Environment (SOE) monitoring site. The current site, near the upstream spring, fails to capture the full impact of catchment inputs, including diffuse pollution from Tokaanu Village and altered sediment dynamics from the diversion. An additional SOE site, coupled with the findings of my thesis, would provide crucial knowledge to support efforts in restoring the Tokaanu Stream's ecological health and the mana of Ngāti Kurauia.

year: 2025

title: Grazing and feeding management to reduce urinary nitrogen excretion and enteric methane emissions while maintaining or increasing milk production

authors: Garrett, Konagh

abstract: Rising global population is driving the requirement for more sustainable food production. Although, pastoral milk production efficiency has improved to meet demand, the intensification of practices has simultaneously increased environmental footprint by increasing methane (CH₄) emissions and urinary nitrogen (UN) excretion. Therefore, design and evaluation of practical on farm mitigation methods are required. The objective of this thesis was to explore strategic feeding managements during early and late lactation, with the aim of reducing methanogenesis and UN excretion, while maintaining milk production.
For the purpose and objective of this work, the mechanistic and dynamic dairy cow model, MINDY (Gregorini et al., 2013, 2015, in press) was used. 
The first modelling experiment evaluated the effect of altering herbage allowance (HA) on dry matter intake (DMI), milk solids (MS), UN, and CH₄ production. As expected, greater HA increased DMI and MS production at a diminishing rate. Increased HA heightened consumption of fermentable carbohydrates and N containing compounds, resulting in greater emissions of both CH₄ and UN. However, with increased HA the emission intensity (g kg MS⁻¹) and CH₄ yield (g CH₄ kgDM⁻¹) declined. The results from this experiment agree with other studies and was used as a basis to add additional strategic feeding management in the following experiments.
The second experiment examined altering the time of herbage allocation to reduce methanogenesis and UN excretion while maintaining MS production. The treatments were a factorial arrangement of HA (as the first experiment) and time of pasture allocation either after the morning (AM) or afternoon (PM) milking. The PM treatments on average had a greater DMI (1.9 and 1.7%) and MS yield (2.3 and 0.7%) as compared to AM, in EL and LL respectively. The PM treatments also produced 5.1 and 3.6% more CH4 and 4.7 and 7.8% less UN in EL and LL, respectively. Altering the time of HA is a simple and cost-effective management practice to reduce the environmental footprint of productive grazing dairy cows.
Finally, supplementation strategies were evaluated on top of experiment two’s treatments by the addition of either maize silage (MZ), maize grain (MG), or barley grain (BG) fed either prior to AM, PM, or each milking. When allocated BG, MZ, and MG in the PM rather than the AM cows respectively consumed 0.2, 8.9, and 1.2% more DM in EL and 4.0, 11.0, and 2.5% more DM in LL. Consequently, PM allocation of BG, MZ, and MG resulted in production of 0.2, 2.2, and 0.3 % more MS in EL, and 1.7, 3.6, and 1.0 % greater in LL. Similarly, the PM supplement allocation on average excreted less UN and emitted more CH₄. However, the weak positive relationship between CH₄ and UN indicates potential to simultaneously reduce their production by altering the time of herbage and supplement allocation. 
Grazing and feeding management tools are inexpensive and easily integrated into practice yet aid in reaching both mitigation and production goals. Further empirical research is required to understand their usage under competitive grazing and use in conjunction with other mitigation techniques.

text: Grazing and feeding management to reduce urinary nitrogen excretion and enteric methane emissions while maintaining or increasing milk production Rising global population is driving the requirement for more sustainable food production. Although, pastoral milk production efficiency has improved to meet demand, the intensification of practices has simultaneously increased environmental footprint by increasing methane (CH₄) emissions and urinary nitrogen (UN) excretion. Therefore, design and evaluation of practical on farm mitigation methods are required. The objective of this thesis was to explore strategic feeding managements during early and late lactation, with the aim of reducing methanogenesis and UN excretion, while maintaining milk production.
For the purpose and objective of this work, the mechanistic and dynamic dairy cow model, MINDY (Gregorini et al., 2013, 2015, in press) was used. 
The first modelling experiment evaluated the effect of altering herbage allowance (HA) on dry matter intake (DMI), milk solids (MS), UN, and CH₄ production. As expected, greater HA increased DMI and MS production at a diminishing rate. Increased HA heightened consumption of fermentable carbohydrates and N containing compounds, resulting in greater emissions of both CH₄ and UN. However, with increased HA the emission intensity (g kg MS⁻¹) and CH₄ yield (g CH₄ kgDM⁻¹) declined. The results from this experiment agree with other studies and was used as a basis to add additional strategic feeding management in the following experiments.
The second experiment examined altering the time of herbage allocation to reduce methanogenesis and UN excretion while maintaining MS production. The treatments were a factorial arrangement of HA (as the first experiment) and time of pasture allocation either after the morning (AM) or afternoon (PM) milking. The PM treatments on average had a greater DMI (1.9 and 1.7%) and MS yield (2.3 and 0.7%) as compared to AM, in EL and LL respectively. The PM treatments also produced 5.1 and 3.6% more CH4 and 4.7 and 7.8% less UN in EL and LL, respectively. Altering the time of HA is a simple and cost-effective management practice to reduce the environmental footprint of productive grazing dairy cows.
Finally, supplementation strategies were evaluated on top of experiment two’s treatments by the addition of either maize silage (MZ), maize grain (MG), or barley grain (BG) fed either prior to AM, PM, or each milking. When allocated BG, MZ, and MG in the PM rather than the AM cows respectively consumed 0.2, 8.9, and 1.2% more DM in EL and 4.0, 11.0, and 2.5% more DM in LL. Consequently, PM allocation of BG, MZ, and MG resulted in production of 0.2, 2.2, and 0.3 % more MS in EL, and 1.7, 3.6, and 1.0 % greater in LL. Similarly, the PM supplement allocation on average excreted less UN and emitted more CH₄. However, the weak positive relationship between CH₄ and UN indicates potential to simultaneously reduce their production by altering the time of herbage and supplement allocation. 
Grazing and feeding management tools are inexpensive and easily integrated into practice yet aid in reaching both mitigation and production goals. Further empirical research is required to understand their usage under competitive grazing and use in conjunction with other mitigation techniques.

year: 2018