title: [Geostatistics analyzing to cause of formation of circle distribution of plant communities in Horqin Sandy Land].
abstract: Investigation results in the present study showed that plant communities took typical concentric circles distribution patterns along habitat gradient from top, slope to interdune on a few large fixed dunes in middle part of Korqin Sandy Land. In order to explain this phenomenon, analysis of water content and its spatial heterogeneity in sand layers on different locations of dunes was conducted. In these dunes, water contents in sand layers of the tops were lower than those of the slopes; both of them were lower than those of the interdunes. According to the results of geostatistics analysis, whether shifting dune or fixed dune, spatial heterogeneity of water contents in sand layers took on regular changes, such as ratios between nugget and sill and ranges reduced gradually, fractal dimension increased gradually, the regular changes of these parameters indicated that random spatial heterogeneity reduced gradually, and autocorrelation spatial heterogeneity increased gradually from the top, the slope to the interdune. The regular changes of water contents in sand layers and their spatial heterogeneity of different locations of the dunes, thus, might be an important cause resulted in the formation of the concentric circles patterns of the plant communities on these fixed dunes.
authors.affiliation: College of Life Science, Nankai University, Tianjin 300071, China. xingd@nankai.edu.cn
authors.forename: Xingdong
authors.initials: X
authors.lastname: He
authors.forename: Yubao
authors.initials: Y
authors.lastname: Gao
authors.forename: Wenzhi
authors.initials: W
authors.lastname: Zhao
authors.forename: Zili
authors.initials: Z
authors.lastname: Cong
mesh_terms: D002681:China; D017753:Ecosystem; D005843:Geography; D063245:Plant Development; D011157:Population Dynamics; D012822:Silicon Dioxide / Q000032:analysis*; D014867:Water / Q000032:analysis
chemical_list: D014867:Water; D012822:Silicon Dioxide