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Project Details
Project status
In progress
Research Framework
Pou Nuku-a-Rangi
Research Duration
Jan 2022 – Dec 2024
Project Overview
Weeds growing together may interact and change each other’s impacts on native species. This project focuses on the interactions between woolly nightshade (Solanum mauritianum), brush wattle (Paraserianthes lopthantha), and tree privet (Ligustrum lucidum) and assesses the types of impacts they have on native plants when they co-occur.
The field research aims to understand patterns of weed co-occurrence by surveying the plants growing with each of the three target weeds compared to those growing under native species in Auckland restoration plantings. Shade house experiments will test the impacts of the weeds on mānuka (Leptospermum scoparium) depending on the different combinations of weed species they are growing alongside and then test how mānuka are affected by the removal of different weed species.
Why This Matters
Currently, most weed research is based on single weed species impacts and management. However, managers are dealing with multiple species at sites. This project will guide managers as to which weeds should be prioritised for removal based on how they interact with co-occurring weeds rather than based solely on the risks they pose as an individual weed.
The research will also serve to fill a gap in our knowledge around the prevalence of different types of interactions that weeds have with native species and each other (positive, neutral, and negative).
Project Objectives
- Identify weed co-occurrence patterns in the field.
- Measure the impacts of multiple weed species on each other and on native plants.
- Detect differences in impacts and recovery based on removal priority
Research Outputs
Conferences:
- Tree’s a crowd: Interactions and Impacts of Woody Weeds in Revegetation Plantings (September 2025)
17th International Conference on the Ecology & Management of Alien Plant Invasions - Who grows there? The plants that co-occur with three woody weeds (November 2025)
New Zealand Ecological Society Conference - Wattle we do about all these weeds? Determining how interactions of co-occurring woody weeds affect restoration plantings (July 2023)
Ecological Society of Australia Conference
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