古尔班通古特沙漠南缘心叶驼绒藜和梭梭种群空间格局的分形特征

Fractal characteristics of spatial distribution pattern of Ceratoides ewersmanniana and Haloxylon ammodendron population in the southern Gurbantunggut Desert,Xinjiang

灌木是防风固沙的主要植被,其种群空间格局的分形特征研究是了解其分布格局、过程和功能,进而提出科学治理措施的基础。应用信息维数和关联维数对古尔班通古特沙漠南缘两个200m×200m样地(A,B)的心叶驼绒藜(Ceratoides ewersmanniana)和梭梭(Haloxylon ammodendron)种群格局进行分析比较。结果表明心叶驼绒藜的信息维数分别为1.7174(A)、1.5420(B);梭梭为1.3755(A)、1.5765(B)。从总体看,心叶驼绒藜的空间格局强度较强,梭梭相对稍弱。两个样地两种灌木之间的信息熵曲线均在5m^15m出现了尺度转变区,表明两样地内两种灌木之间种群结构较复杂程度和格局强度相当。心叶驼绒藜的关联维数分别为1.7078(A)、1.3728(B);梭梭为1.5347(A)、1.6322(B)。表明心叶驼绒藜个体聚集,关联强度较强,梭梭相对较弱。两种灌木之间的关联维数分别为1.7763(A)、1.8799(B)。两物种之间的关联维数值均大于单个物种的关联维数值,表明心叶驼绒藜和梭梭种群整体关联强度较强。

Shrubs are the main plants for resisting wind and fixing sand in the arid and semi-arid areas, the study on the fractal characteristics of their population spatial distribution pattern can reflect their pattern, process and function, and then provide the scientific measures for the desert management. This research applies the information dimension and correlation dimension to analyze and compare the population pattern of the two kinds of shrubs （ Ceratoides and Haloxylon ammodendron） at the two plots, whose dimention is 200 m ×200 m. The resuhs show that： the information dimension of C. ewersmanniana is 1. 717 4 and 1. 452 0 in the plot A and B respectively, while H. ammodendron＇s is 1. 375 5 and 1. 576 5 at the plot A and B respectively. All in all, the intensity of the spatial pattern of C. ewersmanniana is stronger than that of H. ammodendron. The curves of information entropy all have a changeover of 5 - 15 m of the two kinds of shrubs, and they have the similar community complexity and pattern intensity. The correlation dimension of C. ewersmanniana is 1. 707 8 and 1. 372 8 at the plot A and B respectively, while H. ammodendron＇ s is 1. 534 7 and 1. 632 2 respectively at the plot A and B. These values indicate the individuals of C. ewersmanniana are clustered together and have stronger intensity correlation than that of H. ammodendron. The correlation dimension of the two kinds of shrubs is 1. 776 3 and 1. 8799 at the plot A and B respectively and higher than that of each individual species. It shows that the correlation intensity of joint C. ewersmanniana and H. ammodendron is much stronger.