沙袋沙障对沙丘植被特征的影响

Effects of Sandbag Barrier on Characteristics of Vegetation on Sand Dunes

为了解铺设沙袋沙障沙丘植被生长情况及其与麦草沙障对植被影响的差异,采用样方调查法对乌兰布和沙漠实验地铺设沙袋沙障沙丘植物种数、植株密度、平均高度和平均盖度进行了连续3a的调查,并与铺设麦草沙障沙丘及未做任何处理的裸沙丘作对比,研究了不同规格、不同铺设位置和不同铺设时间的沙袋沙障和麦草沙障对植被生长的影响。结果表明,沙袋沙障和麦草沙障铺设时间越长,所在沙丘植被生长情况越好。随着沙障布设时间增大,2种沙障的植被种数、平均高度无显著变化,植被平均密度能够增加到35%以上,植被盖度也分别能够达到36.8%和33.0%。2种沙障对植被的促进作用排序依次是3m×3m方格沙障最大,2m×2m方格沙障次之,1m×1m方格沙障最小;沙障设置部位不同植被生长情况也存在差异,2种沙障植被最好的位置均是在背风坡底,其次是背风坡中和迎风坡,坡顶植被长势最差。通过方差分析认为,沙袋沙障和麦草沙障对植被生长的影响均无显著差异(p=0.14),但是2种沙障与对照相比差异显著(p<0.005)。

In order to obtain the difference of vegetation growth on sand dunes under the influences of paved sandbag barrier and straw barrier,vegetation species number,average vegetation density,height and vegetation coverage of sand dunes in Ulan Buh desert were investigated for three continuous years by quadrat investigation method on dunes protected by sandbag and straw barriers and bare dunes.The specifications,setting location and setting time of the barriers were studied at the same time.The study results show that the longer setting time of the sandbag and straw sand barrier led to better vegetation growth status.With the increase of the setting time,vegetation species number and average height of the two sand barriers remained similar,but their average vegetation density and coverage increased;the average vegetation density reached above 35%,and the vegetation coverage achieved 36.8% and 33.0%,respectively.The positive effects of sand barriers on vegetation increased with the sizes of the barriers： 3 m×3 m was best,followed by 2 m×2 m and 1 m×1 m.The setting locations of sand barriers also mattered regarding the vegetation growth： the best setting location was bottom lee slope,followed by windward slope,middle lee slope location,and top slope.The two types of sand barriers studied showed no difference of the effects on the vegetation growth according to the analysis of variance（p=0.14）,however,the two sand barriers were significantly better than the control（p0.005）.