A basic and applied approach to evaluate natural heritage, conservation and management: example based on wild flora heritage in the Petit-Buech watershed (Hautes-Alpes, France). On the basis of specific pool attributes, we propose it conceptual and methodological process to achieve conservation management in the pan-European Natura 2000 network of selected and protected sites. Maintenance or even improvement of biodiversity in these sites will be encouraged through contractual arrangements with the land managers. Our data set came from a Natura 2000 site near Gap, in the southern French Alps. Multiple Correspondence analysis (MCA) was first performed on the main biological attributes of 665 plant species and this multivariate model was then validated by a probabilistic experimental design. Our results showed that 17.3% of the total floristic richness of France was observed in the study area (57 km(2)). The main and prior conservation groups were composed of oligotrophic, heliophilous and boreo-arctic species. Correlation between the biological groups derived from multivariate analysis and habitat preferendum allowed us to spatialize areas that were most important for conservation management. New species, coming from independent data, were introduced as supplementary rows in our multivariate model, allowing a discussion on their niche width and their natural heritage attributes. We hope that this methodological and pragmatic process make a relevant decision tool for conservation planning.