Background

Open-cast mining is an example of industrial activity with severe environmental impacts.
There is a growing awareness of the economic, ecological and social negative consequences of ecosystem degradation among the general public, policymakers and environmental managers, and restoration of damaged areas is increasingly demanded.
However, cost-effective procedures are still relatively scarce because the huge variety of situations requires a wide range of specific restoration solutions.

Challenges

Quarrying drastically alters the relief and hydrology of the site, entails the complete removal of soil and associated vegetation and fauna.

The loss of soil is a major problem when the extractive activity ceases and the revegetation of the bare surfaces is intended.
A substrate must be introduced to support plant development, but the quality of the materials used for this purpose is often inadequate.

Under Mediterranean climates, scarcity of rainfall and coincidence of drought and high temperatures in summer are additional and important constraints for the restoration of quarries.

Natural colonization is an effective (though slow) process to restore many damaged ecosystems. However, where water availability is low and unpredictable, the original seed bank has been removed with the topsoil and the arrival of propagules from natural sources is limited, restoration must rely on active revegetation.

The use of native plants has been strongly recommended, but in practice it is constrained by the few commercially available materials (seeds, seedlings), by insufficient knowledge on the most adequate species for each site and on the processes to propagate and successfully install them under quarry conditions.