The Effect of Topography on Long-Term Spontaneous Development of Soil and Woody Cover on Graded and Untreated Overburden

Fabio Vicentini,Karel Tajovský,Markéta Hendrychova,Václav Pižl,Jan Frouz

doi:10.3390/f11050602

Abstract

We studied the development of soil and soil fauna, as well as selected vegetation parameters important for litter input into soil, in two chronosequences of postmining sites after opencast lignite mining near the town of Most (Czechia). Both chronosequences did not have tree planting. On the first chronosequence, no leveling or any other measures had taken place after heaping, and the site kept the wavelike appearance created by the dumping process. The second chronosequence was formed by sites levelled by earthmoving machinery and in which shallow topsoil layers were spread. Both chronosequences were about 30 years old, and consisted of 8 and 11 sites for wavelike and levelled sites, respectively. In addition, samples were taken from a birch site outside of the heaps. Results showed differences in the development of tree and herb layers in both chronosequences. In the levelled sites, herb and tree cover increased after levelling, and woody cover developed much slower. In ungraded sites, woody cover developed faster, and the herb layer slower. Soil chemistry showed a similar pattern in both sites over time, characterized by a decrease in pH and sodium ion content. Soil macrofauna in levelled sites showed random oscillations, while it gradually increased with time in wavelike sites. The study suggested that site levelling alters long-term ecosystem development in postmining sites. Wavelike sites tend to develop towards pioneer forests, while leveled sites tend to be covered by grass and herb vegetation.

Highlights

Postmining sites offer a unique opportunity to investigate environmental processes due to the synchronic presence of different stages of soil succession in a restricted area
The development of vegetation cover with site age was different between graded sites and sites
The development of surface vegetation with site In ageflat was different between sites and sites where the original wavelike wascover maintained

Summary

Introduction

Postmining sites offer a unique opportunity to investigate environmental processes due to the synchronic presence of different stages of soil succession in a restricted area. The levelling or bulldozing of heaps of overburden left behind after mineral extraction is a common practice that takes place at the start of the restoration of postmining sites [5,6,7]. As a result of this intervention, microtopographic heterogeneity, represented by heaps that form waves on the land, is typically suppressed, reducing the landscape to a levelled area that reduces the variability of environments available for plants and fauna. Previous studies showed that bulldozing in the western mining areas of the Czech Republic suppressed tree growth and promoted grasses, especially the grass Calamagrostis epigejos, which is known to outcompete herbs and other plants and to reduce the diversity of plant communities [1,9]

Methods

Results

Conclusion