title: Urban forest restoration ecology: factors influencing native tree regeneration and practitioner decision-making processes

authors: Busbridge, Sarah

subjects: Urban ecology

abstract: Restoration ecology is a new and growing scientific field in the natural sciences. Typically restoration efforts have been focused in remote and rural landscapes. However, recently there has been a rise in the number of projects aimed at restoring native forests in urban environments. The long-term success of these projects depends on the sustainability of restoration plantings and their capacity to self-regenerate over time. Our scientific understanding of how to effectively restore functional, sustainable urban forests is increasing, yet we know little about mechanisms driving juvenile native tree regeneration and recruitment in these highly altered environments. Furthermore, ecological knowledge alone is insufficient to guide restoration outcomes in cities. Urban forests are socio-ecological systems and project outcomes are also influenced by the values and knowledge of restoration practitioners. In this thesis, I explore these ecological and social drivers of long-term urban forest restoration success in New Zealand.

In chapter 2 I investigate how drivers of juvenile native tree recruitment vary according to plant species successional status and growth stage. The long-term existence of restored forests depends on their capacity to follow the steps of ecological forest succession into maturity. It is crucial this includes recruitment of native tree seedlings into the sapling stage, especially for middle and late successional species. However, it is unclear whether the drivers that promote juvenile recruitment are generally applicable, or if they vary according to plant successional status and growth stage. Using a forest planting chronosequence approach and negative binomial generalised linear models, I investigated what drivers promote recruitment processes of early and mid-late successional native woody juveniles in 79 restored urban forests across nine New Zealand cities. I found that mid-late successional trees respond to different drivers than early successional species and the relative importance of particular drivers varies according to the trees growth stage. The effects of canopy cover appear generalizable across successional status but not growth stage, while the opposite is true for the effects of microclimate. Older forests host greater seedling abundance, and larger forest patch size is important for mid-late successional species. These results indicate that to promote urban forest successional progress and hence recruitment of native tree juveniles, management approaches should vary depending on restored forest age and site conditions.

The third chapter explores how restoration practitioners in Aotearoa (New Zealand) make decisions in their efforts to re-establish native urban forests and why there is a gap between science-based best-practice restoration and on-the-ground implementation. The science- practice gap is well-documented in the applied sciences, but little is known about how it manifests in the urban forest restoration context where there are multiple objectives and many diverse stakeholders involved. To remedy this knowledge gap, we administered an online survey to practitioners involved in urban forest restoration. We found there is a tenuous link between scientific knowledge and urban restoration practice due to breakdowns in knowledge transfer and barriers to implementation. When restoring, practitioners tend to prioritise planting or weed control over other vital elements such as project planning and quantifiable monitoring. Objectives are commonly broad, vague, and focused on restoration of simple structural ecosystem components but not important functional attributes. Results show that practitioners value interactions with ecology experts and fellow practitioners equally to traditional forms of science communication (e.g. journal articles) as sources of restoration knowledge. This chapter suggests that prioritising interactive, interpersonal science communication and encouraging collaboration between scientists and practitioners would help strengthen knowledge transfer. Additionally, providing practitioners with time- saving resources, adequate funding, and guidance to navigate socio-ecological constraints that arise in urban projects will improve restoration outcomes.

This thesis broadens our understanding of social and ecological drivers of urban forest restoration success and highlights opportunities for improving the efficacy of urban restoration efforts. This research allows us to develop restoration ecology theory and refine best-practice methods for restoration of native urban ecosystems in Aotearoa.

text: Urban forest restoration ecology: factors influencing native tree regeneration and practitioner decision-making processes Restoration ecology is a new and growing scientific field in the natural sciences. Typically restoration efforts have been focused in remote and rural landscapes. However, recently there has been a rise in the number of projects aimed at restoring native forests in urban environments. The long-term success of these projects depends on the sustainability of restoration plantings and their capacity to self-regenerate over time. Our scientific understanding of how to effectively restore functional, sustainable urban forests is increasing, yet we know little about mechanisms driving juvenile native tree regeneration and recruitment in these highly altered environments. Furthermore, ecological knowledge alone is insufficient to guide restoration outcomes in cities. Urban forests are socio-ecological systems and project outcomes are also influenced by the values and knowledge of restoration practitioners. In this thesis, I explore these ecological and social drivers of long-term urban forest restoration success in New Zealand.

In chapter 2 I investigate how drivers of juvenile native tree recruitment vary according to plant species successional status and growth stage. The long-term existence of restored forests depends on their capacity to follow the steps of ecological forest succession into maturity. It is crucial this includes recruitment of native tree seedlings into the sapling stage, especially for middle and late successional species. However, it is unclear whether the drivers that promote juvenile recruitment are generally applicable, or if they vary according to plant successional status and growth stage. Using a forest planting chronosequence approach and negative binomial generalised linear models, I investigated what drivers promote recruitment processes of early and mid-late successional native woody juveniles in 79 restored urban forests across nine New Zealand cities. I found that mid-late successional trees respond to different drivers than early successional species and the relative importance of particular drivers varies according to the trees growth stage. The effects of canopy cover appear generalizable across successional status but not growth stage, while the opposite is true for the effects of microclimate. Older forests host greater seedling abundance, and larger forest patch size is important for mid-late successional species. These results indicate that to promote urban forest successional progress and hence recruitment of native tree juveniles, management approaches should vary depending on restored forest age and site conditions.

The third chapter explores how restoration practitioners in Aotearoa (New Zealand) make decisions in their efforts to re-establish native urban forests and why there is a gap between science-based best-practice restoration and on-the-ground implementation. The science- practice gap is well-documented in the applied sciences, but little is known about how it manifests in the urban forest restoration context where there are multiple objectives and many diverse stakeholders involved. To remedy this knowledge gap, we administered an online survey to practitioners involved in urban forest restoration. We found there is a tenuous link between scientific knowledge and urban restoration practice due to breakdowns in knowledge transfer and barriers to implementation. When restoring, practitioners tend to prioritise planting or weed control over other vital elements such as project planning and quantifiable monitoring. Objectives are commonly broad, vague, and focused on restoration of simple structural ecosystem components but not important functional attributes. Results show that practitioners value interactions with ecology experts and fellow practitioners equally to traditional forms of science communication (e.g. journal articles) as sources of restoration knowledge. This chapter suggests that prioritising interactive, interpersonal science communication and encouraging collaboration between scientists and practitioners would help strengthen knowledge transfer. Additionally, providing practitioners with time- saving resources, adequate funding, and guidance to navigate socio-ecological constraints that arise in urban projects will improve restoration outcomes.

This thesis broadens our understanding of social and ecological drivers of urban forest restoration success and highlights opportunities for improving the efficacy of urban restoration efforts. This research allows us to develop restoration ecology theory and refine best-practice methods for restoration of native urban ecosystems in Aotearoa.

year: 2020

title: Biophysical, environmental, and economic implications of removing imported supplementary feed from a pasture-based dairy farm system - An upper North Island case study

authors: McCahon, Kieran Shaun

subjects: Palm kernel expeller

abstract: The biological efficiency and profitability of pasture-based systems is optimised by matching pasture supply with the nutritional demands of the herd across the year. Despite the importance of grazed pasture to the profitability of pasture-based systems, the use of purchased (i.e., non-pasture) feeds (supplementary feeds) has increased considerably over the last two decades within the New Zealand (NZ) dairy industry. 
Supplementary feeds may be offered to maintain or increase dry matter intake (DMI) and milk production during periods when pasture supply is insufficient to meet herd demands (i.e., a pasture deficit). However, published results indicate that, despite greater milk production and gross farm revenue (GFR), imported supplementary feed is not associated with an increase in profitability. In addition, the intensification of grazing systems through concurrent increases in stocking rate (SR) have been associated with poorer environmental outcomes, such as reduced water quality and increased greenhouse gas (GHG) emissions. 
The primary objective of my Masters project was to investigate the biophysical, economic, and environmental effects of removing imported supplementary feed from a typical pasture-based system in the upper North Island of New Zealand. This was conducted over three years in Northland, New Zealand (35⁰56’39”S 173⁰50’34”E), using a quantitative case-study approach that compared three pasture-based dairy farming treatments differing in SR and the nature of feed supply. As a Control treatment, imported supplementary feed was offered as palm kernel expeller (PKE) during periods of pasture deficit (~ 550kg DM/cow/yr; ~ 10% of the cows’ diet; PKE treatment). This was compared with two alternative systems to remove the need for PKE: 1) reduced SR (Pasture treatment); or, 2) growing potentially high yielding forage crops on the dairy platform and maintaining SR (Cropping treatment). I used the nutrient budgeting software OVERSEER to model treatment effects on nitrogen (N) leaching, phosphorous (P) loss, and GHG emissions. In addition, I conducted a Monte Carlo analysis to investigate economic performance of all three treatments and how it varied over a range of key input prices.
On average, despite no significant difference in milk production, operating profit tended to be lower in the Cropping treatment relative to the PKE treatment. In addition, after accounting for variability in market prices, the Cropping treatment returned a lower operating profit at every probability level relative to the PKE treatment and was, therefore, an inferior system for a profit-focused decision maker.
Milk production and associated GFR were lower in the Pasture treatment compared with the PKE treatment; however, there was no effect of treatment on operating profit at average market prices. When accounting for potential market price variability, the PKE treatment returned a greater operating profit in 70% of scenarios. As a result, the PKE treatment would likely provide a preferable system for a profit-focused decision maker, with low to moderate risk aversion. However, the relative profitability of treatments was highly dependent on the marginal milk production response (MMPR) to supplementary feed. Consistently large MMPRs to supplementary feed were achieved in the current study: 30 to 50% greater than published farm systems experiments. A reduction in the MMPR to supplementary feed by 10% eroded the profit advantage of the PKE treatment. In addition, despite no treatment effect on N leaching, GHG emissions tended to be lower in the Pasture treatment relative to the PKE treatment. As a result, a decision maker, paying or receiving incentives to reduce environmental externalities would likely be indifferent between the PKE and Pasture treatments, even with the large MMPR to supplementary feed achieved in the current study. Depending on the potential response to supplementary feed, profitability may be maintained with the removal of imported supplementary feeds from a pasture based system by decreasing SR.

text: Biophysical, environmental, and economic implications of removing imported supplementary feed from a pasture-based dairy farm system - An upper North Island case study The biological efficiency and profitability of pasture-based systems is optimised by matching pasture supply with the nutritional demands of the herd across the year. Despite the importance of grazed pasture to the profitability of pasture-based systems, the use of purchased (i.e., non-pasture) feeds (supplementary feeds) has increased considerably over the last two decades within the New Zealand (NZ) dairy industry. 
Supplementary feeds may be offered to maintain or increase dry matter intake (DMI) and milk production during periods when pasture supply is insufficient to meet herd demands (i.e., a pasture deficit). However, published results indicate that, despite greater milk production and gross farm revenue (GFR), imported supplementary feed is not associated with an increase in profitability. In addition, the intensification of grazing systems through concurrent increases in stocking rate (SR) have been associated with poorer environmental outcomes, such as reduced water quality and increased greenhouse gas (GHG) emissions. 
The primary objective of my Masters project was to investigate the biophysical, economic, and environmental effects of removing imported supplementary feed from a typical pasture-based system in the upper North Island of New Zealand. This was conducted over three years in Northland, New Zealand (35⁰56’39”S 173⁰50’34”E), using a quantitative case-study approach that compared three pasture-based dairy farming treatments differing in SR and the nature of feed supply. As a Control treatment, imported supplementary feed was offered as palm kernel expeller (PKE) during periods of pasture deficit (~ 550kg DM/cow/yr; ~ 10% of the cows’ diet; PKE treatment). This was compared with two alternative systems to remove the need for PKE: 1) reduced SR (Pasture treatment); or, 2) growing potentially high yielding forage crops on the dairy platform and maintaining SR (Cropping treatment). I used the nutrient budgeting software OVERSEER to model treatment effects on nitrogen (N) leaching, phosphorous (P) loss, and GHG emissions. In addition, I conducted a Monte Carlo analysis to investigate economic performance of all three treatments and how it varied over a range of key input prices.
On average, despite no significant difference in milk production, operating profit tended to be lower in the Cropping treatment relative to the PKE treatment. In addition, after accounting for variability in market prices, the Cropping treatment returned a lower operating profit at every probability level relative to the PKE treatment and was, therefore, an inferior system for a profit-focused decision maker.
Milk production and associated GFR were lower in the Pasture treatment compared with the PKE treatment; however, there was no effect of treatment on operating profit at average market prices. When accounting for potential market price variability, the PKE treatment returned a greater operating profit in 70% of scenarios. As a result, the PKE treatment would likely provide a preferable system for a profit-focused decision maker, with low to moderate risk aversion. However, the relative profitability of treatments was highly dependent on the marginal milk production response (MMPR) to supplementary feed. Consistently large MMPRs to supplementary feed were achieved in the current study: 30 to 50% greater than published farm systems experiments. A reduction in the MMPR to supplementary feed by 10% eroded the profit advantage of the PKE treatment. In addition, despite no treatment effect on N leaching, GHG emissions tended to be lower in the Pasture treatment relative to the PKE treatment. As a result, a decision maker, paying or receiving incentives to reduce environmental externalities would likely be indifferent between the PKE and Pasture treatments, even with the large MMPR to supplementary feed achieved in the current study. Depending on the potential response to supplementary feed, profitability may be maintained with the removal of imported supplementary feeds from a pasture based system by decreasing SR.

year: 2019

title: An analysis of typical errors of young learners of te reo Maori

authors: Houia, Waldo

subjects: te reo Maori

abstract: In 1999, the New Zealand Ministry of Education commissioned the development of a draft proficiency test for learners of Māori in bilingual and immersion settings in Year 5 of schooling (aged 8 - 10). That test was, along with a range of survey materials, produced and piloted in a very short time - 13 weeks. Although it provided a starting point for further development of a proficiency battery, it did not prove sufficiently robust in itself to retain. What it did do, however, was provide a range of useful samples of the speaking and writing of Year 5 students (70 samples were collected from five different schools). These samples revealed a number of common errors, errors which were analysed and are discussed here.

text: An analysis of typical errors of young learners of te reo Maori In 1999, the New Zealand Ministry of Education commissioned the development of a draft proficiency test for learners of Māori in bilingual and immersion settings in Year 5 of schooling (aged 8 - 10). That test was, along with a range of survey materials, produced and piloted in a very short time - 13 weeks. Although it provided a starting point for further development of a proficiency battery, it did not prove sufficiently robust in itself to retain. What it did do, however, was provide a range of useful samples of the speaking and writing of Year 5 students (70 samples were collected from five different schools). These samples revealed a number of common errors, errors which were analysed and are discussed here.

year: 2002-02