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作 者 ：何志斌, 赵文智, 常学礼

期 刊 ：植物生态学报 2004年 28卷 5期 页码：616-622

关键词：荒漠绿洲过渡带；空间异质性；可塑性面积单元；尺度效应；划区效应；

Keywords:Transitional zone between oasis and desert, Spatial heterogeneity, The modifiable areal unit problem, Scale effect, Zoning effect,

摘 要 ：以荒漠绿洲过渡带植被为研究对象，采用地统计理论与方法，以优势植物泡泡刺(Nitraria sphaerocarpa)和红砂(Reaumuria soongorica)种群为例，采用一个样地内2 500个10 m×10 m小样方中获取的植物盖度数据来研究采样尺度和划区方式对荒漠植被空间异质性的影响。其中尺度效应研究的思路是：一是保持粒度（样方）不变，增加幅度（样地）分析其对空间异质性的影响；二是保持幅度不变，改变粒度进行分析。划区效应是在样地尺度（500 m×500 m）上，把整块样地数据聚合成10 m×200 m、20 m×100 m、40 m×50 m、50 m×40 m、100 m×20 m和200 m×10 m等不同形状和不同方向的网格进行地统计分析。结果表明：荒漠绿洲过渡带植被空间异质性受采样尺度和划区方式影响显著。当样地面积小于200 m×200 m 时，所获取的数据不能真实反映泡泡刺种群的空间异质性；当样地面积小于100 m×100 m 时，所获取的数据不能真实反映红砂种群的空间异质性。调查泡泡刺和红砂种群的空间格局时，样方面积在20 m×20 m到30 m×30 m较为合适。植被空间异质性参数对划区方式的敏感性较强，其中泡泡刺种群的敏感性高于红砂种群。

Abstract:The modifiable areal unit problem has significant implications for ecological research that involves the use of spatial data. The objective of the present study was to discuss the scale effect and zoning effect by investigating and analyzing the spatial heterogeneity of vegetation communities in the transitional zone between oasis and deserts. Geostatistical techniques were used to evaluate the spatial characteristics of plant communities. The spatial structures of different plant populations were characterized using exponential model variogram parameters, including nugget (C0), range (A0) and sill (C0+C). Two methods were employed to determine the scale effect of spatial heterogeneity: 1) a constant plot area (10 m×10 m) and the sampling area expanded to analyze spatial heterogeneity of plant populations; 2) the plot area was changed for maintaining a constant sampling area to analyze spatial heterogeneity. In addition, the plots at the scale of 500 m×500 m were clustered into nested units of different shapes and directions (10 m×200 m, 20 m×100 m, 40 m×50 m, 50 m×40 m, 100 m×20 m and 200 m×10 m) and analyzed at a resolution of 10 m×10 m to examine the zoning effect. The results showed that the spatial heterogeneity of plant populations in the transitional zone between oasis and desert were influenced significantly by scale and zoning approach. Using sensitivity analysis, we were able to obtain a suitable sampling area and zoning approach to weaken the scale and zoning effects. The scale at which different parameters were sensitive was variable. For example, C0 and C0+C were relatively sensitive at small scales, A0 was affected significantly by changes at larger scales, and C0 and A0 were relatively sensitive to different zoning approaches. In order to gain more representative vegetation information of spatial heterogeneity, the sampling area should be more than 200 m×200 m for Nitraria sphaerocarpa populations, 100 m×100 m for Reaumuria soongorica populations, and a plot area of 20 m×20 m to 30 m×30 m should be feasible.

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