Liu Jiankang, Bian Zhen, Zhang Kebin, Ahmad Bilal, Khan Alamgir
School of Soil and Water Conservation Beijing Forestry University Beijing China.
Key Laboratory of State Forestry Administration on Soil and Water Conservation Beijing Forestry University Beijing China.
Ecol Evol. 2019 Feb 28;9(6):3367-3377. doi: 10.1002/ece3.4958. eCollection 2019 Mar.
Grazing is one of the major anthropogenic driving factors influencing community structure and ecological function of grasslands. Fencing has been proved to be one of the main measures for rehabilitating degraded grasslands in northwestern China. However, data from combined empirical studies on the effects of different management regimes in desert grasslands are lacking. So we selected long-term fencing (fenced since 1991), mid-term fencing and seasonal fencing (fenced since 2002), and adjacent free-grazing grasslands to investigate vegetation and soil properties on southwest Mu Us desert. Our results showed that fencing increased plant cover, height, aboveground biomass (AGB) of different plant life-form groups, Shannon-Wiener diversity index, Evenness index, Simpson index, total soil nitrogen, total soil phosphorus, and soil organic matter, but decreased plant density, species richness, Richness index, soil bulk density, water content, and pH. However, 22-24 years of long-term complete fencing might cause redegradation of vegetation and soil nutrients, characterized by the reduction of some vegetation properties, biodiversity, total AGB, and some soil properties. Seasonal fencing with 11-13 year was more beneficial to vegetation restoration than that with completely fencing measures. Our study suggests that appropriate artificial disturbances, such as seasonal fencing (winter grazing and summer fencing), should be used after long-term fencing in order to maintain grassland productivity and biodiversity. These findings will help to provide theoretical support for vegetation restoration and sustainable management in grassland under grazing prohibition at Mu Us desert.
放牧是影响草原群落结构和生态功能的主要人为驱动因素之一。围栏已被证明是中国西北退化草原恢复的主要措施之一。然而，缺乏关于荒漠草原不同管理制度效果的综合实证研究数据。因此，我们选择了长期围栏（自1991年起围栏）、中期围栏和季节性围栏（自2002年起围栏）以及相邻的自由放牧草原，来调查毛乌素沙漠西南部的植被和土壤特性。我们的结果表明，围栏增加了不同植物生活型组的植被盖度、高度、地上生物量（AGB）、香农-威纳多样性指数、均匀度指数、辛普森指数、土壤全氮、土壤全磷和土壤有机质，但降低了植物密度、物种丰富度、丰富度指数、土壤容重、含水量和pH值。然而，22 - 24年的长期完全围栏可能会导致植被和土壤养分的再退化，表现为一些植被特性、生物多样性、总AGB以及一些土壤特性的降低。11 - 13年的季节性围栏比完全围栏措施更有利于植被恢复。我们的研究表明，在长期围栏后应采用适当的人为干扰措施，如季节性围栏（冬季放牧和夏季围栏），以维持草地生产力和生物多样性。这些研究结果将有助于为毛乌素沙漠禁牧条件下的草地植被恢复和可持续管理提供理论支持。
