- Smithsonian Research Associate, Smithsonian Environmental Research Center
- Society of Wetland Scientists Europe Chapter, president
- Member Executive Board INTECOL (International Association of Ecology)
- Owner of private company "Knowledge for Nature and Water (KNW)"
- Member editorial board of Wetlands
- Coordinator of the Hotspot ‘Ondiepe Wateren en Veenweidegebieden”, Nationaal Onderzoeksprogramma Kennis voor Klimaat (2007-2014)
- Chairman Center for Wetland Ecology (collaborative center of 7 universities and 3 research institutes) (2005-2015)