Baseline assessment of the MacKenzie Peat Wetland using drone surveying and pest monitoring tools

Abstract

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