科尔沁沙地退化草场土壤养分的空间结构分析

利用地统计学的方法对科尔沁沙地东南缘退化草场土壤养分的空间分析表明:该草场土壤有机质、全氮、全磷和速效钾都具有明显的空间结构特征,但结构异质性的程度和尺度表现各不相同,空间相关度依次为0.788,0.470,0.758和0.650,变程依次为7.8,18.4,5.9和6.5m,分数维依次为1.857,1.881,1.933和1.920。Moran'sI系数在近距离(1～2m)内均在0.4左右,随着距离增大,迅速减少,克立格制图进一步形象地直观描述该地退化草场土壤特性的空间结构特征。指出土壤全氮是该地区草地生态系统退化和恢复关注的重点。

哺乳动物种群系统时空变异性透视

综述了数学和统计学对哺乳动物种群系统生态学过程与环境随机过程交互作用的研究进展，以及种群波动同步性的Moran原理及效应。自然种群最普遍的现象是其数量在时间和空间上的变异性。在不同种群之间，种群大小的波动方式存在显著的差异。阐明和理解这种差异，探讨其随环境条件而改变的潜在规律，是种群和群落生态学的主要挑战之一。种群变异性存在空间分量，在相对大的距离内，种群的波动常同步发生。对种群内部密度制约过程与诸如环境变异性等外部因子交互作用的检验正在成为哺乳动物种群系统生态学领域关注的论题。

Effect of spatial variation on areal evapotranspiration simulation in Haibei, Tibet plateau, China

Quantification of areal evapotranspiration from remote sensing data requires the determination of surface energy balance components with support of field observations. Much attention should be given to spatial resolution sensitivity to the physics of surface heterogeneity. Using the Priestley-Taylor model, we generated evapotranspiration maps at several spatial resolutions for a heterogeneous area at Haibei, and validated the evapotranspiration maps with the flux tower data. The results suggested that the mean values for all evapotranspiration maps were quite similar but their standard deviations decreased with the coarsening of spatial resolution. When the resolution transcended about 480 m, the standard deviations drastically decreased, indicating a loss of spatial structure information of the original resolution evapotranspiration map. The absolute values of relative errors of the points for evapotranspiration maps showed a fluctuant trend as spatial resolution of input parameter data layers coarsening, and the absolute value of relative errors reached minimum when pixel size of map matched up to measuring scale of eddy covariance system. Finally, based on the analyses of the semi-variogram of the original resolution evapotranspiration map and the shapes of spatial autocorrelation indices of Moran and Geary for evapotranspiration maps at different resolutions, an appropriate resolution was suggested for the areal evapotranspiration simulation in this study area.