Mathias Just Justesen

Mathias Just Justesen is a Postdoctoral Researcher in the Department of Geosciences and Natural Resource Management at the University of Copenhagen, specializing in Forest and Landscape Ecology. His research focuses on entomology with a specialty in beetles, examining the effects of forestry practices on insect biodiversity and investigating harmful insects in the Christmas tree and greenery industry.

Dr. Justesen earned his Cand. Scient. in Biology from the University of Copenhagen in 2017. His master's thesis explored the effect of forestry on the diversity of ground beetles (Coleoptera: Carabidae).

His primary research interests include entomology (particularly beetle ecology), forest biodiversity, invasive species management, and biocontrol methods. Dr. Justesen investigates how forest management practices affect insect communities, with particular attention to non-native beetle species in European forests. His work bridges fundamental ecological research with practical applications for sustainable forest management and pest control in commercial forestry operations. A significant portion of his research examines the Christmas tree industry, where he studies pest insects and potential biological control methods.

Analysis of Dr. Justesen's recent publications reveals a strong interdisciplinary focus spanning entomology, forest ecology, and soil science. His work demonstrates how forest structure, management practices, and soil conditions collectively influence multi-taxon biodiversity. Notable research trends include examining non-native beetle establishment in managed forests, developing biocontrol approaches for Christmas tree pests, and investigating soil microbiome applications for forest restoration on former agricultural lands.

Dr. Justesen has gained significant media attention for his role in rediscovering the horned masked bee in Odense after 109 years of absence. This discovery, covered extensively in Danish media during late 2023 and early 2024, highlighted the unexpected resilience of certain species and generated substantial public interest, with coverage across multiple social media platforms and news outlets.

As a postdoctoral researcher, Dr. Justesen collaborates extensively with colleagues across Europe, contributing to large-scale studies on forest biodiversity and ecosystem services. His work combines rigorous scientific investigation with practical applications that address real-world challenges in forest management and conservation.

Dr. Justesen's research is conducted within the Forest and Landscape Ecology group at the University of Copenhagen, which focuses on understanding ecological processes in forest ecosystems and developing sustainable management practices for forest resources. His work integrates field studies, ecological monitoring, and applied research to address contemporary challenges in forest ecology and entomology.