The spatial patterns of soil seed bank and their relationships with aboveground vegetation in an arid desert

Questions: What are the characteristics of the spatial patterns of soil seed bank (SSB) at local scales?
Methods: A plot of 50 m × 50 m square, divided into 100 quadrats (5 m × 5 m) and 100 subquadrats (1 m × 1 m), was prepared to conduct field survey of vegetation and SSBs sampling.
Results: The SSB density in the study area was 404.5 ± 352 seeds·m-2. SSB of shrub species and herbaceous species Ⅱ (occurring only belowground) had moderate spatial autocorrelation), and their spatial dependence increased with increased scale. The spatial patterns of SSB of shrub species and herbaceous species Ⅰ correlated with shrubs within a specific range.
Conclusion: The spatial pattern of SSB had scale dependence features, which exhibited clustered distribution in a certain scale, and they had significant correlation with aboveground shrubs. Therefore, we suggest subsampling larger quadrats with smaller sample units nearby shrubs in desert areas.

研究问题：局域尺度下土壤种子库（Soil Seed Bank, SSB）的空间格局具有哪些特征？
研究方法：设置一块50 m × 50 m的方形样地，将其划分为100个5 m × 5 m的样方与100个1 m × 1 m的小样方，用于开展植被调查与土壤种子库采样工作。
研究结果：本研究样地内土壤种子库密度为404.5 ± 352 粒·米⁻²。灌木物种与仅地下出现的草本类群Ⅱ的土壤种子库均呈现中等程度的空间自相关性，且二者的空间依赖性随尺度增大而增强。灌木物种与草本类群Ⅰ的土壤种子库空间格局在特定范围内与地上灌木显著相关。
研究结论：土壤种子库的空间格局具有尺度依赖性特征，在特定尺度下呈现聚集分布，且与地上灌木存在显著相关性。据此，我们建议在荒漠区域开展采样时，于灌木周边布设大型样方并辅以小型采样单元。