不同生境白刺(Nitraria tangutorum)灌丛沙堆形态特征

Morphological Features of Nitraria tangutorum Nebkhas in Different Habitats

以吉兰泰荒漠绿洲过渡带为研究区,通过对不同生境条件下的白刺(Nitraria tangutorum)灌丛沙堆形态特征、各形态参数间关系及白刺灌丛生长特征进行定量分析。结果表明:(1)随着梭梭(Haloxylon ammodendron)林龄的增加(白刺纯林除外),白刺灌丛沙堆各形态参数变化范围较大,并向长椭球形方向发展,部分向不对称"蝌蚪状"方向演化。(2)4种不同生境条件下,白刺灌丛沙堆各形态参数相关系数均在0.782以上(P<0.01),表现为显著性相关,这是各生境白刺灌丛沙堆协同发展的结果。(3)对各生境白刺灌丛沙堆长轴与短轴、水平尺度与沙堆高度之间进行回归方程分析,分别呈显著性线性关系(R^2>0.721 7)和幂函数、二次函数关系(R^2>0.835 1)且斜率均为正,表明4种生境灌丛沙堆均处于发育阶段。(4)白刺灌丛株高和盖度对灌丛沙堆形态特征有明显影响,即白刺灌丛株高越高、盖度越大,白刺灌丛沙堆高度、底面积和体积也逐渐增大。

The morphological features of Nitraria tangutorum nebkhas in different habitats in the desert-oasis ecotone in Jilantai were investigated.The relationships among the morphological parameters and the growth of N.tangutorum nebkhas were quantitatively analyzed.The results are as follows:(1)The morphological parameters of N.tangutorum nebkhas along their long ellipsoidal direction varied in a wide range with the increase of stand age of Haloxylon ammodendron(except the N.tangutorum area),and the luxuriantly growing thickets evolved in some areas;(2)The correlation coefficients of the morphological parameters of N.tangutorum nebkhas in four different habitats were all higher than 0.782 and showed a significant correlation(P<0.01),which was the result of the cooperated development of the nebkhas in various habitats;(3)The regression equation analysis revealed that there was a significant linear relationship between the length and width(R^2>0.721 7)and a relationship of power function and quadratic function between the horizontal size and height(R^2>0.835 1)of N.tangutorum nebkhas in various habitats.Which indicated that the N.tangutorum nebkhas were all at the developing stage;(4)The height and coverage of N.tangutorum shrubbery affected significantly the morphological features of N.tangutorum nebkhas,that means the height,basal area and volume of the nebkhas were increased with the increase of plant height and coverage of N.tangutorum shrubbery.