Biodiversity and its restoration in limestone quarries: a review

INTRODUCTION: Limestone quarries impact natural areas, and they are spreading in relation to human population growth. Little is known about the impact of limestone quarries and their restoration on biodiversity. OBJECTIVES: This review aims to provide an overview of how biodiversity is assessed in limestone quarries, how it impacts biodiversity, and the restoration practices applied after mining. METHODS: We reviewed the published literature, including a total of 140 studies. RESULTS: Very few studies were designed to include more than one quarry or different control areas. Few studies examined the role of quarries as open habitats during mining operations, while the majority focused on habitat restoration after excavation. Restoration can occur through active or natural processes. Although active restoration, such as soil amendments and planting, was preferred, natural processes may better support communities that resemble those inhabiting natural calcareous grasslands. Even natural recovery often requires active management. Most studies focused on plants and arthropods, with very few addressing vertebrates. The impact of dust emission was mainly analyzed on plants and lichens. CONCLUSION: There is a significant knowledge gap regarding biodiversity in active quarries and limited data on animal communities. Restoration efforts should integrate both active and passive strategies, with improved monitoring programs and broader taxonomic coverage. IMPLICATIONS FOR PRACTICE: Limestone quarries can host significant biodiversity, including several threatened species, such as those inhabiting calcicolous ecosystems. These can be enhanced through targeted restoration, which should involve native and xerophilous plant species, allowing natural processes to begin the recovery process. However, successful regeneration requires mitigation of harsh environmental conditions and alien species colonization. It is crucial to investigate a broader range of quarries and include more natural control areas. Monitoring and conservation actions must also target vertebrates, soil fauna, and microbial communities, especially threatened and early successional habitat species, which often find refuge in these novel ecosystems. This could be achieved by creating targeted microhabitats and improving landscape connectivity to facilitate colonization. Incorporating a traits-based approach would further enhance understanding of the conservation value and ecological dynamics of these environments.