Irati Carabia Sanz
Mining activity generates significant changes in grasslands, fragmenting the ecosystem, reducing ecological functions, severely damaging biodiversity and degrading the soil and landscape. In the Tandilia System (Argentina), which is a refuge for the biodiversity of the Province, this extractive activity has more than a century of history and little has been studied about the impact on the native ecosystem of the mountain pasture. This is steadily declining as the area occupied by quarries continues to expand in tandem with agricultural activity and urbanisation.
There are a total of 158 quarries in the whole system, 87 of which are currently inactive. Of the latter, 25 are located in the district of Tandil, where the Sierra del Tigre Nature Reserve, the region's only protected area, is located. In this, as in other parts of the System, there are patches of mountain grassland with highly threatened native vegetation, as well as animal species whose distribution is also very limited (Liolaemus tandiliensis and Melanophryniscus nigricans). The increase in invasive exotic vegetation is also associated with these impacts, as it has been seen that its germination is faster in the presence of disturbances, constituting a major problem in the area.
One of the abandoned quarries in the Sierra del Tigre Nature Reserve, Tandil, Argentina. ©Irati Carabia Sanz.
In the province of Buenos Aires, the ecological restoration of abandoned quarries is scarce, so the environmental impact of mining activity is not mitigated. In this context, the main objective of this project is to show the feasibility of the ecological restoration of inactive quarries in the study area, by conducting a pilot test in three of them. This is intended to create habitats on the old mining exploration sites located in the reserve, as well as to connect the different patches of native grassland in the area.
Three strategies will be implemented for this purpose. Firstly, volunteer campaigns involving the community will be carried out to remove the invasive vegetation most present in the area (Spartium junceum or Spanish broom), using cutting machines, machines to crush the remains and the application of the arbusticide Tocón, whose active ingredient is Picloram, which prevents the subsequent growth of the parts remaining in the substrate. Secondly, a large part of the rock present in the quarries will be removed by machinery, as it does not allow the substrate to develop properly. Thirdly, soil rich in nutrients and native seeds will be added from nearby patches, and on top of this, adult native vegetation will be planted and translocated. In addition, it is intended to leave limited areas of exposed rock to serve as basking and refuge sites for endangered fauna. All this will generate a favourable habitat for the development of these native species in the Sierra del Tigre Nature Reserve and will allow us to evaluate the possibility of an ecological restoration project of inactive quarries in other degraded areas of similar characteristics along the Tandilia System.
Header: Sierra del Tigre Natural Reserve, Tandil, Argentina. The invasion of the natural grassland by broom (yellow, flowering plant) and pine and acacia (trees) can be observed. ©Irati Carabia Sanz.