Last September, the 12th International Conference on Mine Closure was celebrated in Leipzig (Germany). This conference, organized by the Technical University Bergakademie Freiberg, is one of the world`s reference events among the mine closure professionals. The main conference topics that were discussed and that have been found as the main issues were: establishing integrated life of mine planning, design sustainable land uses from the social and environmental perspective, increasing the post-mining assets value, and establishing stable and self-regenerating ecosystems, among others.
Due to the urgent necessity of improving reclamation of mining areas, abandoned and/ or in transition to close, researchers from IRNAS-CSIC, University of Seville, University of Reading and Haute École Condorcet have collaborated to present a paper and an oral communication in this conference.
Results from the applied strategy of phytostabilisation on mining areas contaminated by heavy metals were presented. In our study area known as Guadiamar Green Corridor, where phytostabilisation have happened over 19 years, forestation has been found to improve soil fertility and microbial biomass, which is an indicator of improved soil quality. Moreover, different tree species have been found to affect soil chemistry and biology in different ways. White poplar was found to increase soil pH and to recover nutrients levels. However, stone pine was found to acidify the soil, increasing heavy metal availability and reducing microbial communities. In conclusion, previous to forestation is recommended to select the most suitable species for the specific conditions of the mining area to reclaim.
In this conference, Marta Gil-Martínez, predoctoral researcher from IRNAS-CSIC, had the opportunity to visit the Wismut Uranium Tailings Remediation Project , which started back in 1991 and currently clean-up, re-contouring and implementation of covers tasks are still in place. Last cover consists in revegetation to establish some forest and pastures areas, in order to maximize biodiversity.
Researchers of the projects RECARE and RESTECO contributed to the 3rd session, devoted to “Protection and restoration of soils”, with the comunication titled “Soil restoration strategies in the Guadiamar River Valley. Evaluation of 20 year of monitoring after the Aznalcóllar mining accident”.
This work is a review of the 20-year monitoring of contaminated and remediated soils, after the Aznalcóllar mine-spill. The application of soil amendments (sugarbeet lime and biosolid compost) was evaluated and results of 14-year changes of pH and organic carbon were shown.
At a large scale, in a soil survey along the Agrio and Guadiamar rivers, high level of Cd and Zn were detected in certain spots of channel and river banks.
Last August, the 9th International Conference on Mycorrhiza was held in Prague (Czech Republic). This conference, organised by the International Mycorrhiza Society, provided a global platform for exchanging the latest mycorrhizal symbiosis knowledge (anatomy, molecular mechanisms, mycorrhizal ecology and functioning) as well as its implications for the ecosystems and for the human society.
Researchers from RESTECO Project, together with collaborators, presented their last results in the session “Advances in biological conservation through a better understanding of mycorrhizal ecology”. A poster was presented with the study of the functional traits of ectomycorrhizal fungi (ECM) in holm oak (Quercus ilex) tree species in trace elements contaminated soils of the Guadiamar Green Corridor (Seville, Spain). In this study, two hypotheses were validated: soil contamination affects ECM species composition and their functionality, and ECM functional traits mediate in the effect of soil contamination on plant status.
Plant traits resulting from evolutionary and physiological processes have produced a global and extraordinary functional diversity among the myriad of species colonizing contrasted habitats within the planet Earth.
Trait-based ecology helps us to understand better the community assemblage, ecosystem function and the responses to environmental changes.
1) Functional traits of trees affect soil properties and provision of ecosystem services. A study of seven tree species planted on remediated soils in the Guadiamar Green Corridor (Seville, Spain) has shown significant differences in traits (SLA, SRL, LDMC, RMDC) and chemical composition of leaves and roots. These traits differences influence the tree capacity to immobilize contaminants (trace elements) into the soil, remediation technique called phytostabilization. Traits also influence tree capacity to store carbon into biomass and soil, therefore contributing to climate change mitigation.
2) Within plant traits, roots are little known, despite their crucial role in the plant strategies of resource use and the ecosytem funcioning. Variation patterns of 5 root traits in 80 woody plant species from 18 samplig sites and 5 zones of South Spain have been studied. A strong correlation among traits indicates a main dimension along the root economics spectrum. However, other dimensions such as root diameter and the association with mycorrhizal fungi are also relevant.
The abstract and copy of the poster can be consulted in Digital CSIC repository:
The RECARE project is focused on preventing and remediating degradation of soils in Europe.
A Plenary Meeting has been held at Hella (Iceland), from May 29th to June 2nd 2017. Each of the 17 study sites participating in the project presented their results.
The Group SOIL-PLANT, from the IRNAS, CSIC, presented their results about two measures applied for the remediation of contaminated soils at the Guadiamar Green Corridor: a) amendment addition and b) tree plantation.
Those results are part of a joint work by the projects RECARE and RESTECO.
In particular, three oral communications were presented within the Symposium “Filling current knowledge gaps: understanding the role of plant-soil interactions on the functioning and resilience of Mediterranean ecosystems in a changing world”:
Marta Gil Martínez has presented the communication “Plant-soil interactions in the Guadiamar Green Corridor: feedback processes between holm oak and their ectomycorrhyzal fungal symbionts”, in the Doctorate Meeting of the Program in Integrative Biology, University of Seville, on January 12th 2017.
The soil organic matter (SOM) plays an important role determining physical (structure, water retention), chemical (nutrient availability, buffer effect), and biological (microbial diversity, biologically active compounds) properties.
There is a generalized problem of organic matter loss in Mediterranean soils, and one of the solutions is to add compost from organic residues, as part of the circular economy.
Soils improved with compost provide with ecosystem services of provision (increasing food production) and regulation (nutrient cycling, carbon sequestration), thus contributing to human wellbeing.
In the Guadiamar Green Corridor (Sevilla, Spain), we are evaluating the effectiveness of combined measures of amendment addition and tree plantation, for two ecosytem services: stabilization of trace elements, and storage of soil carbon.
The IRNAS researchers Teodoro Marañón and Engracia Madejón presented the opening lecture entitled “Soil functions and ecosystem services: the importance of organic matter” (in Spanish), within the V Jornadas de la Red Española de Compostaje, held at Sevilla, Spain, on November 16-18, 2016.
Changes in the natural capital’s properties influence soil processes, which support the provision of ecosystem services. The benefits produced by these ecosystem services are explicitly or implicitly valued by individuals and society. This can influence decision- and policy making at different scales, potentially leading to a societal response, such as improved land management.
A group of scientists within the RECARE project, including Teodoro Marañón (IRNAS, CSIC), has presented a comunication on soil-related ecosystem services at the session Strengthening Ecosystem Services Community of Practices, in the European Ecosystem Services Conference, with the motto “Helping Nature to help us”, that was held at Antwerpen, 19-23 September 2016.
It was proposed an adapted framework for soil-related ecosystem services that is suited for practical application in the prevention and remediation of soil degradation across Europe. It will be applied in the 17 study sites included in the RECARE project.
Gudrun Schwilch, Simone Verzandvoort, Hedwig van Delden, Luuk Fleskens, Elias Giannakis, Teodoro Marañón, Jane Mills, Chris Short, Jannes Stolte (2016). Operationalizing ecosystem services for the mitigation of soil threats. En: European Ecosystem Services Conference, Antwerp, Bélgica, 19-23 septiembre 2016.
A copy of the presentation slides can be consulted here.
One of the scientific sessions was focused on Soil-plant interactions and soil ecosystem services delivery. In this session, researchers of IRNAS, CSIC have presented results on tree plantations in the Guadiamar Green Corridor (Seville, Spain) and their role in soil trace elements stabilization and carbon sequestration.
The importance of tree-soil interactions was remarked for the delivery of two ecosystem services: 1) improvement of soil quality by phytostabilization of contaminants, and 2) mitigation of climate change by carbon sequestration in biomass and soil.