Prescribed burning experiments for restoration of degraded semiarid Mongolian steppe

Abstract

Prescribed burning has been a successful ecosystem restoration tool worldwide. In this study, we burned two different degraded Mongolian grasslands in spring: sparsely vegetated Argalant (ARG) and Hustai National Park (HNP), dominated by the unpalatable forb Artemisia adamsii. We investigated soil properties, seed bank, seedling density, vegetation, biomass, and forage quality before and/or after burning in the grasslands. Burning weakly affected soil properties and significantly reduced seed bank density. Seedling density of Chenopodium aristatum was greater and that of Cleistogenes squarrosa was lower in burned than in unburned plots of HNP, although C. squarrosa showed greater vegetative growth in burned plots. The floristic composition showed small changes after burning, depending on the pre-burning vegetation, but cover of A. adamsii decreased after burning in both ARG and HNP. Thus, the reduced seed bank density by burning led to weak responses of vegetation composition to burning due to strong vegetative growth. However, burning suppressed the unpalatable forb (A. adamsii) and hastened palatable grass (C. squarrosa) productivity, which would be attractive for livestock production, especially for overgrazed areas with low forage palatability. Our findings illustrate the possibility of using spring prescribed burning as a restoration tool in degraded Mongolian steppe, as well as the importance of site-specific conditions for understanding postfire recovery.