Plant Community, Soil and Microclimate Attributes after 70 Years of Natural Recovery of an Abandoned Limestone Quarry

Abstract

With globally more than 100,000 km2 impacted by surface mining at present, and with increasing demand for surface-mined products, land managers are challenged to address landscape degradation of decommissioned quarries, especially in urban areas. In this study, soil, microclimate, and vegetation community data were collected from geomorphologically distinct locations (quarry floor, platform with pond, quarry top, highwall edge) within an urban limestone quarry abandoned 70 years ago without reclamation in central Missouri, USA. Results were compared with two nearby reference sites to bookend conditions in the abandoned quarry, including a recently closed quarry and an urban forest. Results of this study showed that abiotic mining legacies gave rise to distinct vegetation communities comprising 74 native species but also 21 non-native species. Species richness was increased near persistent edges (cliff edge, pond edge) and approached the lower range of species richness found in natural areas in the region. The results of this case study are congruent with the growing body of studies about spontaneous succession on abandoned surface mines worldwide in that spontaneous (vs. managed) revegetation can lead to species-rich, near-natural communities. This finding may justify revision of current legislation requiring technical reclamation of surface mines, especially where favorable substrate, such as limestone, is conducive to swift onset of revegetation. To improve the ecological value of such areas, the provision of funding for long-term invasive species management should also be considered.