Jeroen lives south of Rotterdam in The Netherlands. He is not only interested in searching wild flowers but also in research on mammals (mainly bats and mice). He is a member of the Field Study Group of the Dutch Mammal Society and also studied marine flora and fauna at the Dutch Stichting Anemoon. He works for a water company and has a Master's degree in Cultural Sciences. Jeroen wrote his Bachelor's thesis on a comparison of nineteenth-century civil society in the Netherlands and Belgium by focusing on the foundation of national botanical associations.
Rutger was born in the Netherlands and nowadays lives with his wife and 4 sons in the Province of Limburg, Belgium. He has his own small company for biodiversity research. As a volunteer administrator on waarnemingen.be and observado.org he is responsible for checking photographs and maintaining the species-lists of European plants. He has a website on plants in the Belgian region 'Campine' and is CEO of the company ODI biodiversiteitsonderzoek.