Land rehabilitation in arid Gobi Desert environment using native plant species

Abstract

The ability to rehabilitate disturbed lands and restore ecosystem processes is an important part of the mine closure process, as functional ecosystems maintain long-term biodiversity and ecosystem services values. The Oyu Tolgoi (OT) Mine, located in Umnugobi Aimag, southern Mongolia has to overcome several challenges to develop processes that will assist in the rehabilitation and restoration of areas disturbed by mining development activities. The first challenge was an early commitment to using only native species, which relates to the second challenge posed by the harsh desert climate that the mine is located in. The unprecedented decision to use only native species was a challenge as little research had previously been done on how to grow native Gobi Desert plant species and use them in rehabilitation efforts. This knowledge gap led to the creation of the OT Native Plant Propagation Center (NPPC) in Khanbogd Soum, to conduct research into the collection of seeds, propagation of plants, and preparing seeds and saplings for restoration work. By starting rehabilitation programs early (during the construction stage), OT has had time to develop and test rehabilitation methods and begin to rehabilitate areas to provide time for plants to establish and grow. While OT is still in the construction phase, it has already amassed 10 years of experience in growing native Gobi plant species and rehabilitating disturbed areas through the drill seeding and hydroseeding as well sapling planting method. Preliminary results of comparing biologically rehabilitated areas, where three different methods were applied at the same time, to the background control showed that the sapling planted area showed the greatest similarity (75%) and no difference in vegetation cover and biomass (t = -0.88, p = 0.40; t = -0.22, p = 0.83) with the control. In contrast, the similarity of the hydroseeded area was 45.5%, while the drill seeded area was the least similar to the control area (0%). This suggests that the sapling planting method was the most successful rehabilitation method. However, the study will be continued to include more rehabilitated areas and allow more time for vegetation recovery in rehabilitated areas