Trained as a botanist and phylogenetic systematist, as scientist of Naturalis I focus on biodiversity in urban areas. My main interest is in rewilding cities, i.e., spontaneous plant growth and in soil/vegetation succession as a way towards nature inclusive urbanization. I especially pay attention to what can be called hidden biodiversity, small faunistic and floristic organisms, which play an important role in the urban ecology, but which are mostly neglected or even disliked. A recent focus is on soil biodiversity as the intricate soil biome is carrier of the above ground biodiversity. This has a.o. resulted in https://www.nai010.com/nl/publicaties/biodivercity-a-matter-of-vital-soil/245962. A substantial part of my time I am teaching these topics to students from Leiden university and other academic institutions, including the supervision of BSc- and MSc-internships. I have several projects running in Amsterdam, Leiden, The Hague, and other areas in the west of the Netherlands.