Private gardens hold remarkable potential to foster biodiversity and help counter its alarming decline. Yet, few garden owners place biodiversity at the heart of their design and maintenance choices. As researchers from the University of Jena and iDiv, we were part of the interdisciplinary gARTENreich project, which set out to identify what drives – and what hinders – biodiversity-friendly gardening, while also developing practical solutions.
Through our workshop series with garden owners, we discovered that one of the greatest barriers is a simple lack of awareness: many people do not know what biodiversity needs, or how their gardens can contribute. At the same time, we saw great curiosity. Many participants wanted expert feedback on the biodiversity value of their own gardens. Thus, the idea for a garden biodiversity self-test was born.
The test works much like a magazine personality quiz: tick a few boxes, total the points, and read your result. Behind this simple format lies a robust method. We linked specific garden structures to their biodiversity value through habitat creation, assigning each feature a score based on statistical analysis of sampled gardens. To our knowledge, it is the first tool of its kind to serve both researchers and garden owners.
We have made the test freely available, along with a suite of practical resources, such as instructions for creating near-natural flower beds or dry stone walls, lists of native plants, and guidance for maintaining a biodiversity-friendly garden. All materials are in German and accessible via nabu.de/gartenreich. Municipalities can also adapt these resources for their own websites to further promote wildlife gardening (see gartenreich-projekt.de/downloads). We are delighted that our peer-reviewed paper detailing the self-test’s development, validation, and potential applications has now been published. We hope these tools will empower garden owners to make positive changes and provide researchers with valuable data.
A garden pond with riparian vegetation and without ornamental fish is a great habitat for many species
A meadow with native flowers provides nectar and pollen for numerous insects
The gARTENreich project brought together researchers and practitioners from the Institute for Ecological Economy Research (IÖW), NABU (Nature and Biodiversity Conservation Union) e. V., NaturGarten e. V., Friedrich Schiller University Jena, Berlin School of Economics and Law, and the municipalities of Gütersloh and Aumühle. Running from November 2021 to October 2024, it was funded by the Federal Ministry of Education and Research as part of the FEdA Research Initiative for the Conservation of Biodiversity.
Publication
Felgentreff, E.S., Jakubka, D., Knapp, S., Bernhardt-Römermann, M. (2025): The garden biodiversity index: A self-assessment tool for evaluating biodiversity in private gardens. Landscape and Urban Planning, 263, 105449. DOI: 10.1016/j.landurbplan.2025.105449
Contact:
Esther Felgentreff, esther.felgentreff@uni-jena.de
Markus Bernhardt-Römermann, markus.bernhardt@uni-jena.de