Indicators of the biological diversity of forests at the national level : comments on a French experience

This paper reviews the section devoted to biological diversity in an official and public report on indicators of sustainable management of French forests by the French Ministry of Agriculture. This report is taken as an example with the aim of discussing the nature and relevance of several indicators of biological diversity at a regional or national level, as well as to point out some associated methodological problems. The biological diversity section of this report presents 14 criteria (i.e. groups of indicators) of diversity and sustainability, which may be grouped into 3 broad classes : forest- and ecosystem-oriented indicators; species-oriented indicators; policy- and management-oriented indicators. For each indicator, the way it is estimated as well as its relevance in the context of tropical forests are discussed. This review shows that : assessing the biological diversity of forests requires the combination of many different data sources and viewpoints; there is a need to explicitly link aggregated and indirect indicators of diversity to ecological functions, forest resources and sustainability; many methodological problems persist in the estimation process itself; these indicators should not be evaluated only once, but monitored through a continuous national forest survey; this report contains indicators which do not fit within the tropical context and should therefore be adapted to local condition