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SPATIAL DISTRIBUTION AND LANDSCAPE IMPACT ANALYSIS OF QUARRIES 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 want 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 - 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.
KEYWORDS: Environmental threats; quarries; habitat destruction; native ecosystem; land cover change; conservation.
INTRODUCTION
Quarrying is an extractive activity that causes major environmental changes (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 environment’s ability to provide ecosystem services, severely impacting the native flora and fauna surrounding the quarries (Sala et al., 2010). For example, successional processes cannot proceed in areas affected 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).
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. The number of deposits and grassland remnants affected by the activity has increased in the last decade (Secretaría de minería, 2020). This area is typical granite and limestone opencast mining, where topsoil is removed to expose the rock to be extracted (Cingolani, 2011). Opencast mining usually requires the removal of large quantities of soil and rock. It involves the use of machinery and explosives, which has a negative impact on the landscape, air, and water quality (Iwanoff, 1998). The rainwater fills these opencast mine pits dissolving the minerals such as calcium and magnesium, which percolate downwards through fractures and joints. This increases groundwater pollution by increasing the calcium and magnesium, along with their carbonates, sulfates, and chlorides affecting its hardness (Milgrom, 2008; Bhatnagar et al., 2014). All these described impacts are intensified when the lack of control by governmental authorities results in abandoned pits without mitigation actions (Marchevsky et al., 2017; Zhang et al., 2018). The latter is the case of many abandoned quarries along the Tandilia mountains.
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 Pampa 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 processing satellite images with Geographic Information Systems.
MATERIALS AND METHODS