基于地表土壤动物与植物完整性指数评估若尔盖沼泽湿地受扰现状

Abstract

利用地表土壤动物与植物群落生物完整性指数评价若尔盖沼泽湿地受扰现状，为若尔盖沼泽湿地恢复提供依据。2018年7月与2019年7月对若尔盖10处典型湿地（参照区4个，受扰区6个）地表土壤动物与湿地植被群落进行调查。通过对74个候选指标的分布范围、判别能力及相关分析，确定中生性植物、一年生植物、龙胆科植物、一年生植物/多年生植物比4个植物核心指标，地表土壤动物总个体数量、中小型动物类群数量、蜘蛛目物种数量、菌食性土壤动物与腐食性土壤动物5个核心指标，构建若尔盖沼泽湿地地表土壤动物与植物完整性指数。以所有采样点95%分位数为最佳期望值，四分位法确定研究区域未受干扰、轻度干扰程度、中度干扰与重度干扰4个等级，作为判断若尔盖沼泽湿地受扰状况。结果显示，若尔盖沼泽湿地相对原始沼泽、花湖沼泽化草甸2、长期低强度排水疏干区、短期高强度排水疏干区分别处于未受干扰、轻度干扰、中度干扰与重度干扰状态。所调查的若尔盖典型湿地中，20%的湿地未受到干扰，30%的湿地受到轻度干扰，30%的湿地受到中度干扰，20%的湿地受到重度干扰。Pearson相关系数分析显示，地表土壤动物完整性指数与植物完整性指数存在显著正相关关系（r=0.722，P<0.05），表明地表土壤动物完整性指数与植物完整性指数评价结果具有一致性。;The Zoige wetland, located at the northeast of Qinghai-Tibet Plateau, is the largest plateau wetland in China. There have been substantial changes in Zoige wetland due to natural (climate, soil, and vegetation) and anthropogenic (drainage and overgrazing) impacts. The index of biotic integrity is a comprehensive method for assessing the ecological status of wetlands. The ground-dwelling soil animal and wetland plant are the most widely used biological indicators owing to their distinct advantages for wetland ecosystem monitoring, while there is no indicator framework to determine the disturbed status and benefit of returning grazing to wetland of the Zoige area. The aim of this study is to evaluate disturbance status of Zoige wetland using the ground-dwelling soil animal and wetland plant-based index of biotic integrity to providing data for the restoration of Zoige wetland. In July 2018 and July 2019, the ground dwelling soil animal and plant were investigated from 10 typical wetlands of Zoige were chosen, including 4 wetlands which were undisturbed or less disturbed, and 6 wetlands which were disturbed. The ground-dwelling soil animal and plant-based index of biotic integrity in Zoige wetland were determined through a range of index value distribution, discrimination ability, and correlation analysis of 74 candidate indicators, which included 5 metrics of the number of soil animal individuals, the number of meso/micro soil animal individual, the number of ground spiders, Fungivorous form animal and Saprozoic animal, while plant integrity index including 4 metrics of mesophyte, annuals plant, Gentians, ration of annuals/Perennials. Use the quartile method to determine four grades of undisturbed, mild, moderate, severe disturbance in the study area with 95% quantile of all sampling points as the best-expected value and judge the disturbance status of the Zoige swamp wetland. The results showed that the relatively primary wetland was undisturbance, swamp meadow 2 was mild disturbance, long-term low intensity drainage stress area was moderate disturbance, and short-term high intensity drainage stress area was severe disturbance. Among the investigated typical wetland of Zoige, 20% of wetlands were undisturbance, 30% were mild disturbance, 30% were moderate disturbance, and 20% were the severe disturbance. According to the Pearson correlation coefficient analysis, there was a significantly positive correlation between surface soil animal integrity index and plant communities integrity index (r=0.722, P<0.05), indicating that the evaluation results of surface soil animal integrity index and plant integrity index were consistent.