Submitted to: Rangeland Ecology and Management
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/30/2009
Publication Date: 7/15/2009
Publication URL: http://handle.nal.usda.gov/10113/58482
Citation: Liang, Y., Han, G., Zhou, H., Zhao, M., Snyman, H.A., Shan, D., Havstad, K.M. 2009. Grazing intensity on vegetation dynamics of a typical steppe in Northeast Inner Mongolia. Rangeland Ecology and Management. 62:328-336. Interpretive Summary: One of the key principles for management of livestock grazing on rangelands is the establishment of the proper rate of livestock stocking (numbers of livestock per month per acre). Proper stocking rates are determined based on knowledge of how livestock grazing at different levels of use, or intensity, impacts rangeland health over time. Studies that examine effects of difference of utilization levels, or difference in stocking rates, are part of this process to determine proper stocking. One region of the world where long-term studies on the effects of different stocking rates is needed is in China. This study cited by a collaborating scientist from the USDA, examined effects of 3 different stocking rates against a non-grazed reference area on vegetation of a large grassland regional similar to the Northern Great Plains of the USA. AS with other long-term studies of this nature, heavy stocking rates had undesirable effects but lighter or moderate stocking rates appeared to be sustainable for these renewable vegetative features.
Technical Abstract: Vegetation features radiating from residential areas in response to livestock grazing were quantified for an arid steppe rangeland in the Keshiketeng Banner, Chifeng Prefecture in northeastern Inner Mongolia in 2004 and 2006. The aim of this study was to estimate grazing impacts on the vegetation dynamics of these historical grazed ecosystems. Grazing intensities were classified as reference area (RA), light (LG), moderate (MG) and heavy (HG) according to the vegetation utilization across the study area. Rangelands were studied along a grazing gradient, where characteristics of plant communities, heights of dominant species, above ground vertical structures and below ground biomass were investigated. Along this grazing gradient vegetation changed from the original plant dominant species Leymus chinensis (Trin.) Tzvel to a semi-subshrub species Artemisia frigida Willd in moving from the reference area (RA) to the region around the settlement. Canopy coverage, above ground productivity, and the number of perennial species declined moving towards the residential area. Heights of five dominant species, except for Stipa grandis P. Smirn, declined with increases in grazing intensity. Vertical structure above ground in the RA treatment showed a more resilient model than the other treatments. There were no difference in root biomass in the top 1 m of soil showed no difference (P > 0.05) between the RA treatment and the area immediately around settlement (HG treatment). Generally, we found that the intensity of grazing disturbance did not exceed the tolerance of the rangeland ecosystem within LG treatment. However, vegetative conditions in HG treatment became worse with increases in grazing pressure. Rangelands in this arid steppe are under tremendous threats due to excessive forage utilization that can not be considered as sustainable practices.