典型草原健康评价的VOR和CVOR指数

VOR and CVOR Index for Health Evaluation of Typical Steppe in Inner Mongolia

为准确定量评价围封禁牧对草原生态系统健康的影响,以内蒙古太仆寺旗境内植被组成一致(以羊草(Ley-mus chinensis)+克氏针茅(Stipa krylovii)草原为主)、土壤类型相同的自由放牧样地和围封样地为研究对象,开展自由放牧和围封禁牧对典型草原健康影响的VOR和CVOR指数评价,建立典型草原健康评价的VOR和CVOR综合指数的计算模型,并用于不同围封年限典型草原的健康评价。结果表明:VOR和CVOR综合指数均可准确评价不同围封禁牧年限典型草原的健康状况,两者具有基本一致的评价结果。典型草原在围封恢复演替过程中,尽管草地基况(C)、活力(V)、组织力(O)和恢复力(R)变化各异,但围封禁牧后草地的VOR和CVOR综合指数均随围封禁牧年限的延长呈逐渐增加的变化趋势,草地的健康等级由未围封和围封前期的"警戒"等级逐步恢复演替至"健康"(围封13～20年)等级,表明围封有利于退化草地生态系统的健康恢复。

Effects of fencing on the health of grassland ecosystem in open-grazing land and fenced-land with the same vegetation composition（Leymus chinensis and Stipa krylovii are main species） and soil type are reported.Calculation models for VOR and CVOR index were created and their indices used to evaluate the health of typical steppes fenced in different years.Results showed that VOR and CVOR indices could accurately evaluate the health of typical steppe ecosystems fenced in different years.The evaluation results of both indices were quite consistent.The condition（C）,vigor（V）,organization（O） and resilience（R） of typical steppe in the restoration succession had different change patterns,whereas VOR and CVOR indices showed the same change tendency to increase gradually with prolonged fencing.The health condition of typical steppe was increased from ＂threshold＂ level to ＂health＂ level after fenced 13 years showing that the implement of fencing was beneficial to the health recovery of degraded grassland ecosystem.