Quarrying generates significant changes in the grasslands, by reducing ecological functions, reducing connectivity, impairing biodiversity, and degrading soil. Unlike other forms of destruction such as agriculture or urbanization, mining is characterized by eliminating soil and exposing the bedrock, facilitating groundwater contamination processes. Quarrying in Pampean grassland has been expanding for a century and little is known about the extent and distribution of quarries over the native environment. In this work, we analyze the spatiotemporal variation of quarrying activity on the Highland grassland in the Tandilia mountains of Argentina. Based on Landsat 5, 7, and 8 satellite imagery, from 1996 to 2022, and using QGIS software, we identified the location and extension of quarries, and we analyzed their change through time. Quarries covered 6428 ha, which was originally part of the Pampean grassland. The number of open quarries increased by 129%, from 69 in 1996 to 158 in 2022, and the area used for this activity increased by 172%, with a greater expansion being detected in the last ten years. At least 87 quarries were abandoned in 2022. Quarries are often abandoned without any kind of remediation, leading to further ecosystem deterioration. The current extension of quarrying activity (active and abandoned quarries) reduced the connectivity and a significant area (5.2%) of the Highland grassland of the Tandilia Mountains. Grassland conservation planning should include quarrying as a significant threat, and management actions must be considered to reduce its impact.

Mining activity generates significant changes in the ecosystems in which it takes place, affecting the atmosphere and the surrounding aquatic and terrestrial systems, causing the destruction of landscapes, the loss of vegetation, and altering native environments. As it is an impact associated with increasing urbanization and population growth, the area occupied by quarries has increased worldwide. In the province of Buenos Aires, quarries are often abandoned without any remediation, leading to further deterioration of the ecosystem. This work aims to analyze quarrying activity’s spatiotemporal effect on the Pampean grassland in the Tandilia mountains (Buenos Aires province, Argentina). Based on Landsat 5, 7, and 8 satellite imagery, from 1996 to the present, and using QGIS software, we identified the location and extension of quarries, and we analyzed their evolution through time. Quarries currently occupy an area of 6428 ha, which was originally part of the Pampean grassland. The number of open quarries increased by 129%, from 69 in 1996 to 158 in 2022, and the area used for this activity increased by 172%, with a greater expansion being detected in the last ten years. These results conclude that this extractive activity represents a major threat to the Pampean grassland with the consequent loss of biodiversity and invasion of exotic plants capable of colonizing areas altered by human activity.

Most studies exploring land use impacts have focused on taxonomic metrics, but interest in the functional approach has increased because it helps to understand the relationships between community structure and functioning of aquatic ecosystems. We evaluated how functional and taxonomic approaches contribute to assessing the effects of land use on macroinvertebrate assemblages of lowland streams. We also studied the relationships between both approaches. We sampled benthic macroinvertebrates in 17 sites with different land uses (agricultural, peri-urban, and extensive livestock). We computed the taxonomic metrics and biotic indexes as well as functional richness (FRic), divergence (FDiv), dispersion (FDis), and Rao diversity indexes for each site. We performed general linear mixed models to compare land-uses and also performed correlation analysis between taxonomic and functional indexes. Taxonomic richness was significantly higher in extensive livestock than in the other two land uses, while Shannon diversity was significantly different between land uses (extensive livestock>peri-urban>agriculture). FRic and FDiv were significantly lower in peri-urban land use than in agricultural and extensive livestock sites. Only taxonomic richness showed a significant and positive relationship with FRic, FDis, and Rao, but they fit better to a logarithmic function. Therefore, an increase in taxonomic richness and Shannon diversity did not necessarily imply an increase in the functional aspects of the macroinvertebrate assemblage. Using only one of these approaches could lead to partial evaluations and loss of information. Combining them could improve bioindication and predictive potential and help assess the effects of multiple stressors on freshwater ecosystems to improve biomonitoring.