Miss Joelle Lousberg1,2, Doctor of Philosophy Georgia Thomson-Laing2, Doctor of Philosophy Lena Schallenberg1, Doctor of Philosophy William Godsoe1, Doctor of Philosophy John Pearman2, Doctor of Philosophy Ian Duggan3, Professor Susanna Wood1
1Lincoln University, Lincoln, New Zealand, 2Cawthron Institute, Nelson, New Zealand, 3Waikato University, Hamilton, New Zealand
Biography:
Joëlle is a PhD candidate at Lincoln University, New Zealand, conducting her research in collaboration with the Cawthron Institute. Her research focuses on developing and applying environmental DNA (eDNA) metabarcoding approaches to improve the assessment of lake zooplankton biodiversity in Aotearoa New Zealand.
Originally from Belgium, Joëlle completed a Bachelor's degree in Biology followed by a Master's degree in Ecotoxicology. As part of her master's research, she worked at the Fraunhofer Research Institute, where she developed a flow-through ecotoxicity assay for aquatic macrophytes.
Abstract:
After completing her studies, Joëlle travelled to New Zealand on a working holiday visa. While working as a tour guide in Fiordland, she developed a deep appreciation for New Zealand's unique freshwater ecosystems and lakes, inspiring her to pursue a research career in freshwater ecology. She returned to New Zealand in early 2025 to begin her PhD and has since focused on advancing eDNA metabarcoding methods for freshwater zooplankton. Her research aims to develop robust molecular tools that support biodiversity assessment and freshwater ecosystem monitoring, contributing to improved conservation and management of New Zealand's lakes.
Environmental DNA (eDNA) metabarcoding offers a promising high-throughput alternative to traditional biodiversity monitoring, yet its application to freshwater zooplankton remains challenging, particularly in regions with distinctive assemblages. In Aotearoa New Zealand, lake zooplankton communities are biogeographically unique, historically characterised by calanoid copepod dominance, low species diversity, and year-round breeding patterns. However, increasing eutrophication, invasive zooplankton, and introduced fish are reshaping these communities, creating an urgent need for efficient, large-scale monitoring tools exceeding the capacity of traditional morphology-based taxonomy.
To address this challenge, we developed an eDNA metabarcoding workflow tailored to zooplankton occurring in Aotearoa New Zealand lakes. Using surface water samples and vertical tow nets from lakes spanning the trophic gradient, we evaluated methodological performance and refined an approach capable of capturing diverse zooplankton assemblages. We identified and addressed key challenges associated with incomplete reference databases, primer selection, and taxonomic resolution.
We then applied the optimised workflow to samples from 170 lakes spanning a broad range of environmental conditions – from remote alpine oligotrophic systems to lowland supertrophic lakes – to undertake the first nationwide eDNA assessment of zooplankton biodiversity in lakes across Aotearoa New Zealand. We tested whether eutrophication and introduced fish are driving the homogenisation of zooplankton communities and evaluated broad-scale patterns in community composition across environmental gradients. By combining methodological advances with ecological application, this study highlights both the opportunities and current limitations of eDNA metabarcoding for lake zooplankton biomonitoring while providing new insights into how Aotearoa New Zealand's unique lake ecosystems are responding to environmental change.