微尺度下城市公园人造绿地土壤水分的时空分异格局及其驱动机制

水是生态系统的基本非生物组成要素,土壤水分对生态系统结构和功能有重要影响。微地形改造被证明能有效涵养水源、防止水土流失,并被广泛应用在生态恢复工程中。然而,在微尺度下人造生态系统土壤水分的时空分异格局及其驱动机制仍不明确。选择北京奥林匹克森林公园一处集合了4种不同地形的草地作为研究对象,对表层(0—10 cm)和深层(10—25 cm)土壤水分开展了长期的研究工作。研究结果表明,不同地形上土壤水分的季节变化特征没有显著差异,土壤温度是影响土壤水分季节变化的主要因素。在植被覆盖均匀的条件下,微地形对土壤表层水分的空间分布格局有显著影响,除洼地和冲沟两种特殊地形外,坡度决定的生态水文过程是主要的驱动机制;土壤深层水分没有明显的空间分布格局。研究结果说明在微尺度下,微地形通过影响土壤水分的空间分布格局,可能会对生态系统结构和功能产生潜在影响,应当在景观改造和生态恢复相关研究和工程应用中给予更多的关注。

Pattern and mechanism of microscale spatial-temporal variation in soil moisture at an artificial grassland in an urban park

Water is the most basic element of ecosystem and is crucial to ecosystem structure and function. The transformation of microtopography has been widely used in ecological restoration to conserve soil water. However, the pattern and mechanisms of spatial-temporal variation in soil moisture at the micro-scale remain unclear. In this study, both topsoil (0-10 cm) and subsoil (10-25 cm) water content of four microtopographic types, which were located on an artificial grassland inside Beijing Olympic forest park, were monitored for one year. Only the topsoil water content was significantly affected by microtopography. Through eco-hydrological processes, slope gradient was an important impact factor for the spatial distribution of soil moisture. However, temporal variation in soil moisture showed no response to microtopography and was significantly affected by soil temperature. Therefore, further study is needed to reveal the potential effects of artificial microtopography on ecosystem structure and function, especially in the field of landscape transformation and ecological restoration.