Acknowledgements
We thank C. Godin for having provided the Figure
2a. We warmly thank A. Cambien, A. Banos,
J. Baudry, P. Couteron, and D. Lo Seen for their advice during the process of writing this paper. This
synthesis was developed in the course of several projects funded by the Agence Nationale de la Recherche
(projects “BiodivAgriM” and “INC”, ANR-biodiversité 2007, project “STAMP”, ANR-blanc 2007). We
are thankful to anonymous reviewers for their helpful comments and suggestions on an earlier
draft.