abstract


Steppe desertification due to vehicle travel is one of severe environmental issues in Mongolia. We studied the natural vegetation recovery on abandoned vehicle tracks in the central Mongolia steppe through vegetation survey and the stable isotopic technique. The following issues were addressed: (1) the invasion of pioneering plant species, (2) the alteration of soil surface features, and (3) the contribution of revegetated plants to soil organic matter (SOM). The pioneering plant species that firstly invaded the abandoned tracks are those that could germinate, root and survive in the compacted track surface. Salsola collina is one of these candidate plants. Due to revegetation, soil surface hardness was reduced. With the improvement of surface microenvironmental conditions, other plants began to colonize and establish, concomitantly species richness and species diversity increased. Carbon isotope ratios of SOM at the top surface layer indicated that C4-derived carbon contributed more to SOM in the early phase of recovery and decreased with further recovery.