Quarry rehabilitation: a case study

摘要

Quarrying activities such as limestone extraction entail significant visual impacts and degradation problems as a result of soil depletion and deep alteration to the original topography. These areas are at high risk of erosion due to removal of vegetation and the lack of available soil on steep slopes. In addition, the common method of quarry exploitation in platforms increases drainage and the physical and chemical erosion of the substrate, hindering natural germination and establishment of young plants, and thus delaying recolonisation. In the past, quarries were simply abandoned after extraction. However, natural colonisation of disused limestone quarries is slow. The time scales involved in the creation of new communities are not considered acceptable for reclamation or restoration. A reclamation project was conducted in a limestone quarry within the Serra da Arrabida Natural Park (Portugal), one example of well-preserved Mediterranean vegetation in Europe. We compared the revegetation of 5 abandoned platforms sequentially revegetated over the last 15 years, at 3 year intervals. The successive revegetation of each platform resulted in distinct plant communities, differing in age and cover. This allowed the evaluation of establishment and growth of introduced species as well as the succession of spontaneous species and stabilisation of natural vegetation. The evolution of soil characteristics was also evaluated as well as the contribution of different species to soil formation on the platforms. The results obtained allowed us to recommend strategies and to establish criteria for evaluation of the success of the revegetation in these degraded areas.