围栏封育对荒漠草地群落结构和品质的影响

Effects of enclosure on plant community structure and quality in desert steppe

为监测宁夏盐池不同地段荒漠草原围栏封育的恢复效果以及毒杂害草对封育改良的影响,在一块具有相同恢复措施和年限的围栏草地内分异出4个毒杂害草生长状况不同的典型采样小区。通过样方调查统计群落的基本特征,运用PCA排序方法、相关分析和一元线性回归模型进行数据分析,研究发现,经过9年的围栏封育,草地优势种发生明显变化,并且不同地段的优势种群不同,其恢复进程也各不相同;毒杂害草的大量生长降低了植被的总盖度、物种多度、优良牧草的相对生物量以及优势种群的优势度,使种群结构呈现简单化趋势,促进了牧草的簇状生长格局;草地系统的自然恢复过程不能明显控制老瓜头(Cynanchum komarovii)、刺叶柄棘豆(Oxytropisaciphylla)等有毒植物的生长和繁殖,应该采取适当的人为干扰措施。

In order to monitor the different lots’ restoration of desert steppe and the influence of poisonous plant on enclosed steppe in Yanchi County of Ningxia Province,a piece of steppe with same restoration years and ways was chosen as an experimental field.Within the experimental field there were 4 plots being selected to investigate the vegetation according to growth of poisonous plants in each plot.Basic characteristics of communities were investigated by quadrat survey;and PCA sort method,correlation analysis and a linear regression model were used to analyze data obtained from the experimental field.Results showed that after 9 years of fencing,although composition species of communities did not change a lot,dominant species changed significantly in each plot;and there were different dominant species in different plots with different recovery rates.A large number of miscellaneous toxic grasses reduced the total cover of vegetation,species abundance,biomass of good forage and dominance of dominant species,so that the community structure presented simplificative and pasture growth patterns of clusters were promoted.The natural recovery process of grassland systems can not significantly control the growth and reproduction of poisonous plants,such as Cynanchum komarovii and Oxytropis aciphylla.Therefore,human being should give appropriate disturbance during the restoration of desert steppe.