Résumé
Restoration ecology is an emerging science dealing with applied ecology and aiming at “helping nature to recreate itself”. This comprehensive paper presents the findings and main results related to the analysis of natural vegetation dynamics on abandoned limestone quarries in Mediterranean environment. It aims to answer three basic questions: where, when and how should intervention by ecological restoration be achieved in abandoned limestone quarries. Results show that quarries are heterogeneous ecosystems and interventional strategies should be planned according to the different landforms observed. Quarry faces potentially host a particular saxicolous flora often composed of rare and endemic species, intervention is not recommended, unless required by urban planning issues. Intervention on platforms can be very expensive (substratum fracturing) and involves heavy engineering works. Restoration on quarry embankments aims at orienting and accelerating natural regeneration processes in order to shortcut the first stages naturally dominated by annuals and ruderal species. 27 species suitable for revegetation purposes have been identified for the different bioclimatic levels in Lebanon. They respond to two major criteria: availability in the natural surroundings (indigenous species) and adaptability to local conditions (pioneer adapted species). In conclusion, this paper suggests future openings for a development field integrating economical opportunities on solid scientific bases.