围封对希拉穆仁草原植被和土壤种子库的影响

围栏封育有利于受损草地生态系统的恢复。通过在希拉穆仁草原进行5年的围封试验,对样地的植被和土壤种子库进行连续监测的方法,研究围封对退化草地的地上植被与土壤种子库的综合修复效果。结果表明:①围封样地植被产量、盖度和高度等生产性能明显高于重牧样地。种类数和Shannon-Wiener生物多样性指数则围封样地低于重牧样地。围封样地中克氏针茅和羊草等优质牧草占优势,重牧样地中冷蒿、银灰旋花和猪毛菜等劣质牧草占优势。②降水量是影响年际间土壤种子库状况的主要因素。围封可促进草地土壤中各种植物种子的积累。围封样地土壤种子库中克氏针茅占多数,重牧样地劣质牧草种子占多数。围封可提高草地生产性能和土壤种子库的积累,但长此以往不利于草地生物多样性,因此应适当中轻度放牧以提高草地的生物多样性。

Influence of Fencing on Vegetation and Soil Seed Bank in Xilamuren Grassland

Fencing is conductive to damaged grassland ecosystem restoration.5 years fencing experiment from 2007 to 2011 was carried out to continuously monitor the sample fields’ vegetation and soil seed bank,and to study on the comprehensive restoration effect of fencing on the vegetation and soil seed bank in Xilamuren degraded grassland,Inner Mongolia.The results showed as follows: ① Biomass,coverage and height of fencing plot are notably more than that of heavy grazing plot.Stipa krylovii and Leymus chinesis are dominant and therefore the lower the Shannon-Wiener biodiversity index is.The production of heavy grazing plot is less than the fencing plot.Aritimisia frigida,Convolvulus ammannii and Salsols collina etc.are dominant and therefore the larger the Shannon-Wiener biodiversity index is.②Precipitation decides the situation of soil seed bank.Fencing promotes the cumulative of all plant seeds in soil.There is a big difference in soil seed bank between fencing plot and heavy grazing plot,the former Stipa krylovii is dominant,the latter Aritimisia frigida,Convolvulus ammannii and Salsols collina et al.are dominant.Fencing can promote production performance of grassland and accumulation of soil seed bank,but fencing for long-term is not conductive to grassland biodiversity.Moderate or light grazing can promote grassland biodiversity.