Current

• Secretary General of SCOPE, Scientific Committee on Problems of the Environment, 2001- present.
  
  
• Editor Global Change Biology, Blackwell Scientific, 2003-present.
  
  
• Editorial Board of Climate Research, Inter Research, 1992-present.
  
  
• Editorial Board of Oecologia, Springer Verlag, 1994-present.
  
  
• Editorial Board of Ecosystems, Springer Verlag, 1997-present.

Past

• Member of the Governing Board of the Ecological Society of America, 2002-2004.
  
  
• Scientific Committee for the International Geosphere-Biosphere Programme (IGBP), 1994-1996.
  
  
• Scientific Steering committee of Global Change and Terrestrial Ecosystems (GCTE), a core project of the International Geosphere Biosphere Programme, 1991-1999.
  
  
• Leader, Global Change and Terrestrial Ecosystems (GCTE). Focus 4, Global Change and Ecological Complexity, 1994-1999.
  
  
• Steering committee of America's Interhemisphere Geo-Biosphere Organization (AMIGO), 1991-1995.
  
  
• Scientific Advisory Committee of the Biodiversity and Ecosystem Functioning: Soils and Sediment, a program of the Scientific Committee on Problems of the Environment (SCOPE), 1995-1999.
  
  
• Scientific Advisory Committee of Diversitas, An International Programme of Biodiversity Science, IUBS, SCOPE, UNESCO, ICSU, IGBP-GCTE, and IUMS, 1995- 2001.
  
  
• Chair of "Red LatinoAmericana de Botánica"2001-2004
  
  
• Scientific Steering Committee of "Red LatinoAmericana de Botánica"1999-2001.
  
  
• Biology Panel, National Research Council of Argentina, 1989-1992.
  
  
• Vicepresident Ecological Society of Argentina, 1991-1993.
  
  
• President Ecological Society of Argentina, 1997-1999 and 1999-2001.
  
  
• Editorial Board of Global Change Biology, Blackwell Scientific, 1994-2003.
  
  
• Editorial Board of Plant Ecology (formerlyVegetatio), Kluwer academic publishers, 1990-1996.
  
  
• Scientific Steering Committee of SCOPE, Scientific Committee on Problems of the Environment, 1998-2001.