**Author details**

The ecological theory that is most applicable to the restoration of the environmental impacts of capped landfills addresses the stress and ecological strategies of herbaceous species.

The classification of plant life cycle strategies described by Grime combines the stress intensity with the perturbation intensity [7, 28]. Thus, "competing species" are more appropriate for landfills with a low intensity of perturbation and stress, "ruderal" species adapt better to conditions of low stress and intense perturbation, and "stress-tolerants" are ideal for settings of intense stress and scarce perturbation. When both these factors are excessive, this approach

It should not be forgotten, however, that different types of ecosystem respond differently to a given perturbation, and vice-versa, that a given ecosystem can respond in many different ways to different perturbations. We also need to be aware of the vast environmental variability and

If a sealed landfill needs to be revegetated, it will be necessary to study the fertility of its soil cover, heavy metals and trace elements that can cause plant toxicity, salinity and organic compounds in the capping soil layer. The research methodology used in the landfill case study

The analysis of all considered parameters and the heterogeneous distribution of pollutants indicate that a single-species cover should be avoided. It will be necessary to create a multi‐ species cover that will adapt to the heterogeneous distribution of the organic and inorganic pollutants present in capping soils and to the morphological features of the landfill's slopes.

From a scientific viewpoint, the scenario of the closed waste landfill has enabled the in depth study of what we have called the erosion-pollution binomial. This is the complex situation found in the capping soils of closed landfills in the Mediterranean setting. The plant species used for their revegetation should have the capacity to show an adequate response to this biome. To find such species, there is an urgent need for autecological studies and studies designed to assess native and commercial plant species that are able to adapt to these particular conditions. This is the reason why these results should not be extrapolated to other non-

Authors acknowledge program P2009/AMB-1478 Community of Madrid Program (EIADES). MJGG was funded by the FPU fellowship (AP2008-02934) of Spain's Ministry of Education.

randomness that exists along with other associated forms of uncertainty [29].

can be followed in other scenarios with a similar problem.

is ineffective.

220 Environmental Risk Assessment of Soil Contamination

**5. Conclusions**

Mediterranean settings.

**Acknowledgements**

Jesús Pastor1 , María Jesús Gutiérrez-Ginés1\*, Carmen Bartolomé2 and Ana Jesús Hernández2

