Grazing Intensity on Vegetation Dynamics of a Typical Steppe in Northeast Inner Mongolia |
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| Authors: | Yan Liang Guodong Han He Zhou Mengli Zhao Hennie A Snyman Dan Shan Kris M Havstad |
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| Institution: | 1. Research Associate, Rangeland Ecology, Department of Grassland Science, College of Animal Science and Technology, China Agricultural University, Beijing 100193, People’s Republic of China;2. Professors of Rangeland Ecology, Inner Mongolia Agricultural University, Huhhot, Inner Mongolia 010018, People’s Republic of China;3. Professor, Rangeland Ecology, Department of Grassland Science, College of Animal Science and Technology, China Agricultural University, Beijing 100193, People’s Republic of China;4. Professor, Rangeland Ecology, Department of Animal, Wildlife, and Grassland Sciences, University of the Free State, PO Box 339, Bloemfontein 9300, South Africa;5. Research Associate, Rangeland Ecology, Inner Mongolia Agricultural University, Huhhot, Inner Mongolia 010018, People’s Republic of China;6. Supervisory Scientist, US Department of Agriculture–Agricultural Research Service Jornada Experimental Range, New Mexico State University, Las Cruces, NM 88003-0003, USA;1. Key Laboratory of Plant Resources, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China;2. University of Chinese Academy of Sciences, Beijing 100049, China |
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| 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, aboveground vertical structures, and belowground biomass were investigated. Along this grazing gradient, vegetation changed from the original dominant plant species Leymus chinensis (Trin.) Tzvel. to a semi-subshrub species Artemisia frigida Willd. when moving from the reference area (RA) to the region around the settlement. Canopy coverage, aboveground productivity, and the number of perennial species declined as one moved toward the residential area. Heights of five dominant species, except for Stipa grandis P. Smirn., declined with increased grazing intensity. Aboveground vertical structure in the RA treatment showed more resilience than the other treatments. There was no difference in root biomass in the top 1 m of soil (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 increased grazing pressure. Rangelands in this arid steppe are under tremendous threat due to excessive forage utilization, which cannot be considered a sustainable practice. |
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