1. Dynafor; Univ. de Toulouse, INRA, INPT, INP-EI Purpan; Castanet Tolosan France
2. Fenner School of Environment and Society; Australian National Univ.; Canberra ACT 2601 Australia
3. School of BioSciences; Univ. of Melbourne; Parkville Victoria 3010 Australia
4. Centre for Biodiversity Theory and Modelling; Theoretical and Experimental Ecology Station, CNRS and Paul Sabatier Univ.; Moulis France