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SPATIAL DISTRIBUTION AND LANDSCAPE IMPACT ANALYSIS OF QUARRYING IN A HIGHLY FRAGMENTED ECOSYSTEM
Irati Carabia-Sanz, María V. Simoy, Agustina Cortelezzi, Clara Trofino-Falasco & Igor Berkunsky
Instituto Multidisciplinario sobre Ecosistemas y Desarrollo Sustentable, UNICEN - CICPBA, Paraje Arroyo Seco s/n, Tandil (7000), Argentina.
Correspondence: Irati Carabia-Sanz, Instituto Multidisciplinario sobre Ecosistemas y Desarrollo Sustentable, UNICEN - CICPBA, Paraje Arroyo Seco s/n, Tandil (7000), Argentina.
Email:irati.casanz@gmail.com
KEY WORDS: Environmental threats; quarries; habitat destruction; native ecosystem; land cover change; conservation.
Running title: Impact of quarries in a fragmented ecosystem.
Acknowledgments: The authors are grateful for funding from the Universidad Nacional del Centro de la Provincia de Buenos Aires (03-PIO-65H). We would like to thank Felisa for their commentaries and support. I. Carabia-Sanz was supported by fellowships from the Comisión de Investigaciones Científicas de la Provincia de Buenos Aires (CICPBA). A. Cortelezzi, M.V. Simoy and I Berkunsky are Research Fellows of Consejo Nacional de Investigaciones Científicas y Técnicas de Argentina CONICET.
ABSTRACT - 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.
KEY WORDS: Environmental threats; quarries; habitat destruction; native ecosystem; land cover change; conservation.
INTRODUCTION
Quarrying is an extractive activity that causes major environmental changes in grasslands (Lameed & Ayodele, 2010; Gbedzi et al., 2022). The environmental impacts of these changes range from pre-operational mining activities (e.g., construction of access roads, conduits, and installation of drains and ditches) to the mining activity itself (e.g., creation of openings, perforation, blasting, machinery movements; Matías et al., 2007; Souza & Sánchez, 2018). Quarrying impacts result in severe modifications of land cover at the local scale and affect the whole environment, including the lithosphere (rock excavation and geomorphic changes of the landscape), atmosphere (dust and air pollution), hydrosphere (changes in surface water), and biosphere (habitat destruction and biodiversity loss; Lameed & Ayodele, 2010; Bétard, 2013). The habitat destruction and fragmentation severely reduce the grassland’s ability to provide ecosystem services with severe impacts on the native flora and fauna surrounding the quarries (Sala et al., 2010). For example, in areas affected, successional processes cannot proceed and are stuck at the early stages of colonization, mainly due to thin topsoil, without seed banks and rootstocks (Flavenot et al., 2015; Lamare & Singh, 2016).
The rapid population growth coupled with industrialization has increased tremendous pressure on natural resources resulting in the rapid exploitation of mineral resources worldwide (Bhatnagar et al., 2014). For example, in Lebanon, quarrying had an increase of 117% in 20 years (Darwish et al., 2011), while Bijolia (India) showed an increase of 3570% in land use from 1971 to 1992 (Sinha et al., 2000) and Odublasi quarry in Ghana 107,66% increase from 2007 to 2014 (Koranteng & Adu-Asare, 2018). Even when quarrying affects small areas at the regional scale (e.g.; less than 1% of French national territory; Bernaud & Le Bloch, 1998), this extractive activity still has important consequences on the local scale (Flavenot et al., 2014). There is a gap in scientific knowledge about increased quarrying activity on Neotropical native grasslands (Le Stradic et al., 2014). Moreover, in the Neotropic, there are no guidelines that decision-makers can follow to reduce the negative effects of this activity and its abandonment by carrying out environmental impact studies or ecological restoration projects (Figueiredo et al., 2023).
In the Pampa ecoregion, one of the largest grassland regions of the world, the effect of quarries has been overlooked, and the evolution of this activity could be following the global trend. The quarrying activity in Pampa has more than a century of history, and the number of deposits and the number of grassland remnants affected by the activity increased in the last decade (Secretaría de Minería, 2020).
Considering the overall context, the general objective of this study is to accomplish a spatiotemporal analysis of habitat loss due to opencast mining activities in the Tandilia mountains, southern of the Pampean ecoregion. Our specific objectives were: (1) to identify the locations where quarrying takes place, (2) to determine the area of active and inactive quarries, their expansion speed, and their evolution over the last 20 years, and (3) to assess the impact of the extractive activity on the landscape. These objectives are achieved by obtaining Landscape 5, 7, and 8 satellite images and processing them with Geographic Information Systems (QGIS 3.24.2).
MATERIALS AND METHODS