【目的】研究西北干旱地区重要固沙植物梭梭及沙蒿种群空间分布格局和动态,为荒漠化治理与植被恢复提供科学依据。【方法】在乌兰布和沙漠梭梭(Holoxylon ammodendron)+沙蒿(Artemisia desertorum)群落典型分布区域设置1 000 m×1 000 m的样方,于2006和2019年进行2次原位调查,采用点格局分析方法,分析荒漠优势物种的空间分布格局、种间关系及动态变化。【结果】沙蒿灌丛的分布格局由0~20 m尺度的聚集分布,转变为大于10 m尺度上的随机分布,种内关联性呈现减弱的趋势。梭梭灌丛在0~10 m尺度范围内即呈现显著的聚集分布特征。相较于2006年,2019年梭梭的聚集尺度进一步减小,种内关联紧密性有所增强。2006年,梭梭-沙蒿在不同尺度上具有较强的尺度依赖性,在0~18 m尺度内呈现显著的正向作用关系;随着尺度增加,正向作用关系逐渐减弱,表现为相互独立的作用关系。到2019年,正向作用尺度有所减少,在0~15 m即表现为显著的正向作用。【结论】随着时间推移,乌兰布和沙漠梭梭-沙蒿的种间作用尺度有所增强,竞争关系加剧。今后应尽量将梭梭及沙蒿栽种成集群分布而非均匀分布的形式,进而提高植被覆盖率,增强荒漠生态系统功能。

【Objective】Haloxylon ammodendron and Artemisia desertorum are important sand-biding plants in the arid region of the northwest China. Studying the spatial distribution patterns of populations of these two species can help elucidate the population dynamics, which is of great significance to desertification control and vegetation restoration. 【Method】A 1 000 m × 1 000 m quadrat was set in the typical distribution area of H. ammodendron and A. desertorum communities in Ulan Buh Desert, where two in situ surveys were conducted in 2006 and again in 2019. Point pattern analysis was used to analyze the spatial distribution patterns, interspecific relationships, and dynamic changes in dominant desert species. 【Result】The results showed that the distribution pattern of A. desertorum changed from an aggregation distribution at a scale of 0-20 m to a random distribution at a scale of >10 m, and the intra-species correlation showed a weakening trend. The aggregation scale of H. ammodendron decreased further compared to that in 2006, indicating that the intra-species association of H. ammodendron shrubs was enhanced. In 2006, H. ammodendron -A. desertorum had a stronger dependence at different scales, with a significantly positive relationship at the 0-18 m scale. With an increase in scale, this positive relationship weakened and was characterized by an independent relationship. By 2019, the magnitude of the positive effect was reduced, and the positive effect was significant at 0-15 m. 【Conclusion】These results indicate that the inter-specific interaction scale between H. ammodendron and A. desertorum increased with time, and the competition relationship was intensified. If H. ammodendron and A. desertorum are planted in a cluster instead of uniformly distributed, the vegetation coverage rate is expected to be improved, resulting in enhanced function of desert ecosystems.