青海河南高寒草地生态系统健康评价

Health assessment for alpine grassland ecosystem of Henan County in Qinghai Province

以青海省河南县高寒草地为研究区域,从"植被状况-土壤状况-干扰状况-生态系统价值"4个方面的17个指标构建高寒草地生态系统健康评价体系(目标层A、准则层B、因子层C).利用层次分析法确定评价体系中各指标权重,最后利用综合指数法进行高寒草地生态系统健康评价.结果表明:准则层中植被和土壤状况所占权重较大,分别为0.453 4和0.298 4,在高寒草地生态系统健康评价体系中占有主要地位,其中,因子层土壤有机质、地上生物量和植被盖度权重较大,分别为0.168 2,0.164 9,0.164 9,对高寒草地生态系统健康影响显著,虫口密度、土壤碳储能力和牧草生产对草地生态系统健康影响较小,其权重分别为0.007 5,0.010 5,0.010 5.青海河南高寒草地生态系统健康状况评价较好,除样地7外皆属于健康之列.但样地3和样地5评分较低,偏向恶化.应在草地处于初级退化阶段时,积极采取保护措施.

The authors took alpine meadow of Henan County in Qinghai Province as the study area,through dividing the ＂vegetation state,soil conditions,interference condition and ecosystem values＂as four aspects using 17 indicators.Ecosystem health evaluation system for alpine meadow was constructed and divided into target layer A,criterion layer B and factor layer C.Then AHP was used to determine the index weight.Finally,alpine grassland ecosystem health was determined based on comprehensive index evaluation method.The results showed：vegetation and soil conditions accounted for greater weights in criterion layer,which was 0.453 4 and 0.298 4,respectively.They occupied major positions in the ecosystem health evaluation system of the alpine meadow.In the factor layer,the weight of soil organic matter,aboveground biomass and vegetation cover was 0.168 2,0.164 9 and0.164 9,respectively,having significant impact on the alpine meadow ecosystem health.Population density,soil carbon storage capacity and forage production had less impact on themeadow ecosystem health,the weight of which was 0.007 5,0.010 5 and 0.010 5,respectively.The evaluation results showed that the grassland ecosystem health of Henan County in Qinghai Province was preferences except plot 7.However,the scores of sample 3 and sample 5 were too low,having the trend of deterioration.Protective measures should be taken when grassland degradation is in the initial stage.