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‘To lands unknown’: One family’s journey across space and time
No full textThe British Empire’s expansion across the world often resulted in individuals or families migrating from familiar cultural surroundings to unfamiliar lands. This paper focuses on one family’s intergenerational migration beginning in County Monaghan, Ireland, with subsequent journeys to India, England, Australia, and Aotearoa New Zealand. Some of the key events that impacted these journeys were An Gorta Mór or the Great Irish Famine, the Indian Rebellion of 1857, and World War. Microstudies such as this help to illuminate the effects of colonisation and imperialism on the reasons to migrate, cross-cultural relationships, issues of identity, language, and religion
Predicting distribution and establishment of two invasive alien Daphnia species in diverse lakes in New Zealand-Aotearoa
No full textThe freshwater zooplankton of New Zealand-Aotearoa are species-poor with only two indigenous Daphnia species: D. thomsoni, and D. tewaipounamu. Over the last two decades, two species of invasive non-indigenous Daphnia, D. pulicaria/pulex and D. galeata, have become well established in many lakes in New Zealand-Aotearoa and their distribution appears to be rapidly increasing. We report the current distribution of these two invasive species in approximately 300 lakes throughout New Zealand-Aotearoa and test the hypothesis that the distribution and establishment of these invaders is more closely related to human access to a lake than to any environmental attributes of a lake’s water or biota and consider potential implications of our findings for lake management. Boosted regression tree analysis identified total nitrogen and distance from the coast (D. pulicaria) and annual lake temperature (D. galeata) as key variables explaining current distributions. Inclusion of spatial autocorrelation overwhelmed other explanatory variables, highlighting the greater likelihood of spread from known source locations. Proximity to a road was an important predictor for D. pulicaria, and when tested separately both invasive Daphnia occurred significantly more often in lakes within 200 m of a road. Critically, D. galeata’s realised niche completely envelopes D. thomsoni’s, which could force the native species to become extinct through competitive exclusion. These results suggest that the spread of D. pulicaria and D. galeata to lakes where they do not yet occur is unlikely to be prevented unless public access to these waterways is denied or strictly controlled
Prediction of stem extension of lucerne (Medicago sativa L.) in early spring
No full textThe ability to predict the time of rapid stem extension in spring can be used to assist the development of lucerne grazing management plans. Therefore, the aim of this work was to validate the APSIM_Lucerne height function generated by Yang et al. (2021) for early spring. Two experiments in 2022 and 2023 used four winter defoliation dates (01/06, 03/07, 17/07, 01/08) to measure the time and rate of initial stem extension (height) in spring. The data were used to validate the APSIM_Lucerne height function which is based on thermal time accumulation targets modified by photoperiod. The current exponential decay curve in ASPIM showed a poor agreement (RMSE = 2.1) because it had limited data through the winter period. This
was modified using the 2022 and 2023 field data, which showed the start of stem extension occurred at a
photoperiod of 11.1 h. This was consistent with the original dataset. The change in photoperiod direction was accounted for calculating a weighted mean photoperiod from the start of the regrowth rotation (in a
decreasing photoperiod) up to the 11.1 h increasing photoperiod until the end of rotation. This improved
(RMSE = 1.49) the prediction of plant height and is recommended for implementation into the
APSIM_Lucerne framework. In the field, the start of maximum stem extension occurred at an 11.1 h in both
years, which suggests this is the critical photoperiod required before rapid stem extension occurs. However,
this remains to be validated in other environments
Growth performance, carcass characteristics and meat sensory evaluation of broiler chickens fed diets with fermented cassava leaves
No full textObjective: The objective of the study was to determine the effects of feeding fermented cassava leaf meal (FCLM) on growth performance, carcass characteristics and meat sensory evaluation of broiler chickens.
Methods: A total of 160 Cobb-500 chickens were used during the phases of growing (21 days of age; initial weight 0.39±0.025 kg/bird) and finishing (35 days of age; initial weight 1.023±0.164 kg/bird). The whole experiment lasted for four weeks. The FCLM was included in starter and finishing diets at 0, 50, 100, and 150 g/kg inclusion levels. Total feed intake (TFI), weight gain (WG), feed conversion ratio, and nutrient digestibility were recorded. Sensory evaluation of breast meat was used to determine the eating quality of the meat prepared using roasting and boiling methods.
Results: The TFI and WG decreased (p0.05) on the eating qualities of breast meat. However, juiciness was significant (p<0.05) for the cooking method and treatment interaction. At 50 g/kg inclusion level, boiled meat had a higher (p<0.05) juiciness score than roasted meat. Tenderness, on the other hand, was significant (p<0.05) for the interaction of gender and treatment. Females considered the boiled meat to be more tender than the males at 150 g/kg inclusion level. Using principal component analysis, a positive correlation was observed between teeth adhesion and fibrousness, flavour and juiciness, and springiness and tenderness.
Conclusion: From the study, it can be concluded that FCLM can be used as an ingredient in the diets of broiler chickens. Inclusion level of 50 g/kg can be used in chicken diets during the growing phase, whereas in the finishing phase, inclusion level of 150 g/kg FCLM can be used. The FCLM did not affect the eating quality of breast mea
Comment on 'An examination of the ability of plantain (Plantain lanceolata L.) to mitigate nitrogen leaching from pasture systems'
No full textIn their review: An examination of the ability of plantain (Plantago lanceolata L.) to mitigate nitrogen leaching from pasture systems, Eady et al. (2024) dispute both the historic estimates of typical urine patch nitrogen (N) load and leaching and the evidence for the N leaching reduction mechanisms of plantain; and question the recommended levels of plantain required to achieve N leaching reduction. We reject the suggestion that the urine patch has little influence on N leaching, and that average annual N leaching from dairy farms is 6 kg N/ha. We agree that the low dry matter content of plantain is the dominant and best documented effect of plantain on urine N dilution. We reject that there is no evidence for the effect of plantain on nitrogen partitioning to urine, and on potential nitrification rate in the urine patch. We point to empirical evidence of statistically significant reductions in nitrate leaching from plantain at paddock scale, at levels as low as 21% plantain of dry matter eaten. Current research will improve understanding of the mechanisms and magnitude of the effect of plantain on N loss, paving the way for recognition of other forage-based N loss reduction options, and ongoing development of mechanistic models that are adaptable to other forages
A mine for women? Trajectories of Kanak women in the nickel industry in New Caledonia
No full textBased on the analysis of a sample of biographical trajectories, this article attempts to reconstruct the constraints experienced by Kanak women who join the nickel industry, and the strategies they use to enter and remain in the industry. During the 2010s, the nickel sector saw a rapid influx of Indigenous women, often into skilled positions. By cross-referencing the pathways taken by these employees, we shed light on this phenomenon by endeavoring to reconstruct the contradictions and inherent fragility associated with these pathways. To this end, the chapter examines ethnic and gender divisions in the New Caledonian labor market, the country’s specific arrangements for vocational training, and gender relations in the domestic and public spheres, particularly within mining companies. The legacy of the Kanaks’ forced relocation to reserves is also explored. As such, this chapter pursues the dialog opened by research conducted on gender relations in and around the workforce in a postcolonial context, while taking care not to exoticize what is happening in New Caledonia
Impact of river management on groundwater recharge from braided rivers
No full textA new conceptualisation describing surface water-groundwater exchange for braided rivers and their associated alluvial aquifers has been developed (Wilson et al., 2023 Preprint). This conceptualisation recognises that braided rivers create their own high-permeability shallow aquifer system through the process of mobilising bed sediments during flood events. A braided river can therefore be considered a “river system” consisting of surface channels and an intrinsically linked subsurface gravel reservoir, the “braidplain aquifer”. This conceptualisation implies that for settings where the river system is hydraulically disconnected to the regional aquifer, groundwater recharge is largely governed by braidplain aquifer width. Additionally, for settings where the river system is hydraulically connected to the regional aquifer, river bed levels will have a large control on recharge rates since they determine the hydraulic gradient. Depending on the hydraulic status, groundwater recharge can be compromised by narrowing the active braidplain, and bed degradation caused by extracting gravel from the braidplain aquifer at a rate that exceeds natural replenishment. To test the impact of river management on groundwater recharge, long-term records of river mean bed level from surveyed cross sections were compared to groundwater levels for the Wairau and Ngaruroro rivers in New Zealand. Scenario testing for different river system widths and elevations was also conducted in MODFLOW based on shorter term monitoring records.
In New Zealand, groundwater monitoring commenced after the river flood engineering schemes of the 1960’s, so the impact of river narrowing is not captured by groundwater records. However, hydraulically connected recharge reaches of the Wairau and Ngaruroro river systems have both been subject to more recent bed degradation caused by gravel extraction. The long-term groundwater level decline in the regional aquifers clearly mimics the drop in mean bed levels in the recharge reaches of the rivers. The drop in river bed elevations can also account for the decline in groundwater levels in MODFLOW scenario modelling.
Observation data for the Wairau and Ngaruroro systems show that the dynamic component of recharge pulses from flood flows propagate rapidly through their associated highly transmissive alluvial aquifers. For both hydraulically connected and disconnected braidplain aquifer-regional aquifer settings, maintaining a steady rate of recharge is therefore most beneficial for sustaining groundwater levels throughout the year. The observation data and modelling results confirm that gravel extraction in the braidplain aquifer is having the largest impact on the hydrological function of the regional aquifer in the two hydraulically connected systems studied here. In both cases, the decline in bed levels offsets the benefit of recharge sourced from flood flow events
Assessing economic impact of weed control strategies in autumn sown wheat crops in New Zealand
No full textGlobally, weeds are major biotic stressors in crop production systems causing yield loses of up to 35%. Herbicides have been a cost-effective way to mitigate yield losses due to weeds. However, extensive use has resulted in the development of herbicide resistance across multiple weed species and herbicide mode-of action groups. An Australian study reported the overall cost of weeds to grain growers was $3.5 billion. There is an opportunity for similar evaluations to provide value to the New Zealand cropping industry. In the face of herbicide resistance and increasing weed control costs, the development of economically viable integrated weed management strategies are increasingly important. Crop competition is such a tool that has been successfully implemented overseas but assessment in New Zealand context. This non-chemical weed control option may provide the opportunity to reduce herbicide use, mitigate herbicide resistance, reducing the cost of weed management programmes while increasing life expectancy of chemicals. This study will seek to quantify the economics of weed management in autumn sown wheat and test whether competitive wheat cultivars with different growth characteristics is a viable non-chemical weed control option for New Zealand growers. The experimental design features a paired plot Youden design that incorporates three herbicide management programmes and three autumn-sown wheat cultivars. The aim of this study is to develop integrated weed management programmes that balance profitability, crop productivity, acceptable levels of weed control and herbicide resistance management
Engagement in genetic technologies for biological conservation: for whom, how, and for what ends?
No full text‘Engagement’ is increasingly seen as critical to genetic technology governance. It is the most wide-spread principle in gene drive governance documents internationally and is widely included in relevant codes of ethical conduct and risk assessment processes. However, there are clear shortcomings in emerging practices of engagement for genetic technologies. It is therefore important and necessary to foreground critical perspectives on ‘engagement’: that is, to ask questions of whom is engaged and by whom, how and on what terms, and for whom or what those processes serve. This paper unpacks the concept’s normative expectations and empirical conditions in the context of gene drive developments for biological conservation. It demonstrates that despite the rise of rhetoric of engagement for genetic technologies, these efforts strongly lean towards superficial practices that reinforce knowledge hierarchies and existing power dynamics. This work is as part of a five-year interdisciplinary project that looks at gene-drive development in the context of wasp management
A meta-network analysis of methodological specifications for system dynamics modelling application in agricultural food systems
No full textThis paper aims to review existing applications of system dynamics modelling in agricultural food systems and draw insights from the various modelling procedures in order to highlight best-practice guidelines on methodological specifications for SD modelling. A meta-network analysis was used to identify existing studies that have applied SD modelling in agriculture. Using an algorithm that automatically clusters closely connected research articles based on Boolean search strings that look at the title, keywords, abstract, and digital object identifier (DOI) of the journal articles, 354 journal articles were selected for in-depth content analysis.
Based on the synthesised trends, two criteria for determining the type of modelling process and model type to apply for the model conceptualisation step are: (i) the immediate end goal of the modelling process, and (ii) data availability. Participatory modelling is appropriate when there is limited data and model outputs will inform the implementation of interventions by stakeholders. For action research focusing on well-researched food systems with substantial data available, the semi-participatory modelling process can be adopted, and quantitative SD models can be solitarily used. A key contribution of this paper is the proposed procedure for emergent participatory scenario development within the system dynamics modelling process