Environmental Management Dissertations and Theses

Permanent URI for this collection


Recent Additions

Now showing 1 - 5 of 8
  • Item
    Exploring sustainability in community based natural resource management groups in Southland, New Zealand
    (2020) Riemersma, Annichje; Southern Institute of Technology (Invercargill, N.Z.)
    AIM To investigate the experience of locals who are involved in Community Based Natural Resource Management groups in Southland, NZ, and their thoughts on sustainability of groups.
  • Item
    Baseline assessment of the MacKenzie Peat Wetland using drone surveying and pest monitoring tools
    (2020) Fieldes, Walter; Southern Institute of Technology (Invercargill, N.Z.)
    AIM The aim was to measure and provide baseline data of mammalian pest abundance across different vegetation zones and land uses within the Makenzie Wetland. Different monitoring methods were used and compared to evaluate the accuracy of the techniques. The results will be used to guide further research and fieldwork within the MacKenzie Wetland. ABSTRACT Wetlands provide many important ecosystem services such as, maintaining water quality, flood protection, and habitats for both flora and fauna. It is estimated that less than 10% of NZ’s wetlands remain in a natural state with Southland holding nearly 20% of this. Despite the threatened status more than 176 hectares are lost in the region every year. The MacKenzie Wetland is a 54-hectare, raised dome mire wetland located near Limehills, just out of Winton. The area was historically farmed but is now a protected QEII Covenant restoration project and is one of the last remaining wetlands in the area. The aim of the project was to create an updated aerial image of the area using a drone and to measure and provide baseline data of mammalian pest abundance within the MacKenzie wetland. Monitoring pest populations helps show pest abundance and potential effects on the restoration of native vegetation and on the fauna that inhabit the area. Drones are slowly becoming more accessible and can produce high-resolution imaging that is valuable for monitoring and decision making. Two tracking tunnel surveys and a 7 night chewcard survey were carried out to compare their capabilities as survey tools and to provide Relative Abundance Indices for each identified species. Drone survey images were uploaded into software which produced a high-resolution orthophoto map of the wetlands in which native and pest plants were able to be identified. Results from all monitoring events were uploaded to the MacKenzie Wetlands project on the Trap.nz website which is an information management system that converted results into heat maps showing areas where pest species are present. Mice were the main species detected with all methods, while cats were only detected using tunnels with fresh rabbit meat over 3 nights. Delays caused by the COVID-19 pandemic lockdown meant that monitoring took place over winter with fewer tunnels than recommended which could have influenced the results but overall, the aims of the project were met and provide a base for future monitoring projects on the wetland
  • Item
    Dairy farm water quality trends at AB Lime
    (2020) Dungca, Crystal Joy; Southern Institute of Technology (Invercargill, N.Z.)
    AIM The aim of this project is to conduct water quality analyses at AB Lime dairy farm by exploring the five years’ worth of water quality data along with the current data collected. The data will then be used to identify seasonal trends and discuss the impacts of current dairy farm practises to these trends. These finding will then be used to recommend strategies of sustainable dairy farm practices. ABSTRACT Water quality monitoring is an essential way to help sustain lands. This is particularly important in dairy farms where constant inputs of excess nutrients on the soil and water affects the aquatic environment. This research analyses five years’ worth of previously collected water quality data, along with current data from a recently converted cut-and-carry land to a dairy farm at AB Lime Ltd, located in Winton. AB Lime’s unique location gives a great opportunity to carry out water quality testing and analysing as all the surface water can be attributed to the dairy farm since it is situated at the very top of a catchment. The data comes from water samples that were taken from identified nine sites where surface water and tile drains exit the farm. AB Lime follows the Standard Operating Procedure (SOP) for monthly dairy farm water sampling to ensure water quality samples were taken and sent to the Hill Laboratories correctly. The researcher adhered to these guidelines throughout the data collection. Seasonal trends of water parameters and biological parameters have been identified: Winter to Spring will see concentration of nitrates increase in the water exiting the farm. E. coli concentrations tend to proliferate in dry summer periods associated with higher water temperatures, attributing to more favourable conditions for regrowth. Similarly, Total Ammoniacal Nitrogen (TAN) concentration tends to intensify when weather is dry with high temperatures. No general seasonal trend has been associated with DRP concentration; however, it was found that the lower the concentration the severe the effect in the aquatic environment, stimulating algal growth in the water which can be toxic for livestocks, while rainfall events contribute to level of turbidity. The knowledge gained from this study allows the AB Lime’s staff to help the farmers understand the importance of water quality monitoring in order to make decisions around dairy farm practices for better water quality as well as giving recommendations of strategies on the farm. It is important that the AB Lime farm continues to monitor long-term water quality in order to provide swift mitigations on factors that could be degrading the water. Following the lead of AB Lime, it would be advantageous for all farms to undergo consistent water quality monitoring, especially given that Farm Environmental Management Plans (an important part of the consenting process for farms) require that farms shows good management practices around the discharge of contaminants to surface water.
  • Item
    Carbon dioxide and methane emissions from pasture soils and wetland soils, Kapuka dairy-farm, Watituna catchment
    (2020) Dang, Mary; Southern Institute of Technology (Invercargill, N.Z.)
    Over the last century, increasing concentrations of atmospheric carbon dioxide and methane have caused global warming and climate change. Soil, a huge stock of carbon, plays an important role in driving the amount of atmospheric greenhouse gases because soil can absorb and release a considerable quantity of carbon. In New Zealand, agricultural soils account for a large proportion of greenhouse gas emissions. However, the actual magnitude of soil emissions is underestimated due to very limited soil-gas measurement protocols in place for the farming land. This lack of evidence-based data causes uncertainty on the estimates and the trending of greenhouse gas emissions in any given region. Importantly, it fails to effectively inform the future management decisions in adopting strategies to improve soils for reducing the emissions and turning soil carbon sources into carbon sinks. The study investigates the quantity of carbon dioxide (CO2) and methane (CH4) diffusing from pasture soils and wetland soils in a dairyfarm, Kapuka, Waituna catchment. It also assesses the spatial variability of the emissions associated with changes in soil moisture and temperature. Based on results, farm management guidelines have been recommended. The chamber technique and West System portable flux meter were used in the measurements. The monitoring was carried out on the plot of 105 measuring points. At each point, the chamber was placed on the ground surface for the gases diffusing into the instrument and being detected by the sensors. Soil moisture and air parameters were also measured and recorded. The data collected was then processed, analysed, and mapped by using ArcGIS tool. The results show the site is source of CO2 and CH4 emissions. The CO2 flux emits at the average of 17.5 g/m2/day, and the CH4 flux at 0.04 g/m2/day. Compared to the global rate, the study site emits a 120% higher increase in nominal flux. The wetland is a significant source of CO2 and CH4 with very high spatial variability. The highest CH4 flux was recorded at 5.1g/m2/day. Soil moisture, excess nutrients, and shallow water table are the driving factors for the emissions. It is recommended that farm management should focus on improving poorly drained soils, increasing soil organic matter content, and considering riparian planting to reduce nutrient runoff. Future research is recommended to assess the temporal variation of gas emissions and to particularly monitor nitrous oxide. Nitrous oxide is a major component of agriculture gas emissions that come from fertiliser application and manure deposit. Soil gas monitoring in wetlands and farming ‘hot spots’ within the region is also recommended
  • Item
    Do trees reduce water runoff during flood events? An assessment of soil hydrological properties in three different land-use types of varying tree density
    (2020) Schwarz, Elain; Southern Institute of Technology (Invercargill, N.Z.)
    The effect of trees on soil hydraulic and physical properties has been of interest for several centuries. While a variety of relevant studies have been undertaken in Europe, Northern America, Asia and Africa, very few studies have been conducted in New Zealand. This study aims to add some understanding and awareness to the overall pool of knowledge regarding New Zealand’s ecosystems, soils and the link to its vegetation. Three different land use types were tested; a grassland paddock (P), a 20-year-old restoration forest (RF) and a 400-year-old native Kahikatea dominant forest (KF). The main assessments included infiltration rate measurements (IR) and soil moisture content (SM). Hereby a single-ring infiltrometer and a Time Domain Reflectometry (TDR) device were used. The average infiltration rate values tended to KF > RF > P, with the Kahikatea forest soil scoring 18 times higher (200.58mm/hr) than the pasture (10.97mm/hr) and 9 times higher than the restoration forest (21.92mm/hr). The average soil moisture content resulted in P = RF > KF with an overall difference of only 10.6% between the paddock/restoration forest and the Kahikatea forest (74.2%). The experiment proved that trees promote infiltration rates, water storage capacity and reduce surface runoff, hence decreasing the risk of perpetuated flood events. Trees are therefore a suitable tool for practicing natural flood management, to slow the spread and lower the level of a possible flood.