Characteristics and gaps in the assessment of progress in mine restoration: insights from five decades of published literature relating to native ecosystem restoration after mining

Desires that mine sites are restored to self-sustaining native ecosystems providing benefits for people have been longstanding. However, achieving and demonstrating progress toward mine restoration goals is complex and requires sustained assessment of numerous disparate components. The recently released Society for Ecological Restoration Mine Site Restoration Standards (SER MSRS) recommend utilizing restoration science assessments to determine whether sites are developing toward similarity with targeted ecosystems and exhibiting self-sustainability. We conducted a global review of publications that assessed restoration to native ecosystems after mining. Our objectives were to (1) document case studies of long-term assessments of mine restoration and (2) evaluate the extent to which restoration assessment has reported the achievement of varied mine restoration goals on a global scale, including (3) whether any ecosystem components and restoration attributes are underrepresented in published assessments. Among the 712 publications we collated, we documented case studies with sustained reporting on similar restoration and significant increase over time in the quantity and breadth of attributes and ecosystems assessed. Nevertheless, notable gaps remain, or underreporting persists. For example, there have been relatively few assessments targeting understanding of key ecosystem processes, resilience, and threats to ecosystem persistence that are necessary for demonstrating "self-sustainability." Our review also revealed limited consideration of ecosystem services that rarely involved impacted communities. We recommend efforts to collate and expand assessments of similar restoration trajectories, placing more focus on indicators that enable the evaluation of characteristics and progress toward a self-sustaining socioecological ecosystem, to help achieve the goals of mine site restoration.