毛乌素沙地东南缘植被恢复中优势灌木的保育作用分析

Nurse Effect of Dominant Shrubs in Vegetation Regeneration in the Southeastern Marginal Zone of the Mu Us Sandland

以毛乌素沙地东南缘优势灌木作为保育植物,选择油松(Pinus tabulaeformis)和樟子松(Pinus sylvestris)幼苗作为目标物种,将其分别种植在开阔地和优势灌木冠层下,连续3 a统计松树幼苗的存活率和主枝生长长度,从而确定毛乌素沙地优势灌木对松树幼苗的定居是否存在保育作用。同时,测量开阔地和灌木冠层下的环境指标,揭示优势灌木保育作用产生的机理。结果表明:1优势灌木冠层下松树幼苗的总存活率显著高于开阔地(P<0.05),说明优势灌木可增加松树幼苗的存活率。2在持续3 a的恢复实验期间,优势灌木对松树幼苗定居的保育作用不随时间的变化而发生改变。3优势灌木冠层下松树幼苗的主枝生长良好,并未受到抑制。4优势灌木通过改善微环境,从而对其冠层下松树幼苗的定居产生保育作用,其中改善最为明显的是光照强度和土壤湿度,其次是土壤的有机质和全氮含量。总的来说,优势灌木对松树幼苗的定居存在保育作用,保育植物技术可作为一种有效的恢复措施,应用在毛乌素沙地东南缘的植被恢复中,从而为该区植被的恢复与生态保护提供基础数据。

In this study,Pinus tabulaeformis and Pinus sylvestris,two dominant shrub species in the southeastern marginal zone of the Mu Us Sandland,were selected as the nurse plants. The pine seedlings were independently planted under the canopies of shrub species and in open areas to investigate their survival rates and bough growth length in three consecutive growth seasons,and the nurse effect was tested. The results are as follows： 1 The survival rate of pine seedlings under the canopy of shrub species was remarkably higher than in open areas,which indicated that the survival rate of pine seedlings could be increased under the canopy of dominate shrub species;2 During the consecutive three-year regeneration experiment,the nurse effect of the canopy of dominate shrub species did not change with the time; 3 The boughs of pine seedlings could grow well under the canopy of the dominant shrub species; 4 A nurse effect could be provided for the ecesis of pine seedling by improving the microenvironment of dominate shrubs. The improvement of the sunshine intensity and soil moisture content was the most significant,and than the soil organic matter content and total nitrogen content. In conclusions,the nurse effect of canopy of the dominant shrubs could be used as an effective regeneration strategy in the southeastern marginal zone of the Mu Us Sandland.