Councilor of International Association of Bryologists (IAB) 1993-2003.
Editor of Myrinia, a bryological amateur journal, 1991-2002.
Editor of Bryological Times, an international newsletter issued by International Association of Bryologists, 1990-2003. Distributed in over 600 copies around the world.
Editor (bryophytes) of Folia Cryptogamica Estonica 2007-
Chairman of the European Committee for Conservation of Bryophytes (ECCB) since 1994.
Expert member of the European Council’s Bern Convention ”Group of Experts on the Conservation of Plants”, 1999-.
Member of the SSC Bryophyte specialist group of IUCN
Member of Planta Europa Steering Committee since 2004.