Effects of Shrub on Understory Herbaceous Plants and Soil Properties in the Restoration Processes of Degraded Vegetation in Horqin Sand Land

27 Mar Effects of Shrub on Understory Herbaceous Plants and Soil Properties in the Restoration Processes of Degraded Vegetation in Horqin Sand Land

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Abstract

应用野外调查和室内分析方法，通过对科尔沁沙地沙丘固定和植被恢复过程中（流动、半流动、半固定和固定沙丘） 灌丛内外草本植物的特征和土壤的理化性质分析，研究了灌丛的发育对草本植物和土壤的影响。结果表明， 4 种沙丘小叶锦 鸡儿灌丛下植物的盖度、高度和密度显著高于灌丛外围，由灌丛内向灌丛外呈现出明显下降的趋势。通过差巴嘎蒿、小叶锦 鸡儿和冷蒿 3 种灌丛内、外的理化性质的对比分析表明，沙地灌丛的形成对灌丛下土壤有机碳、全氮、全磷、有效氮和有效 磷均有不同程度的富集作用，特别是对土壤有机碳和全氮有明显的富集作用，其大小顺序为小叶锦鸡儿>冷蒿>差巴嘎蒿； 小叶锦鸡儿灌丛对全磷和有效磷的富集作用明显大于其它灌木。这些结果表明在沙丘植被恢复过程中灌丛的发育具有明显的 “保种”作用和“肥岛”效应，促进了沙丘植物的侵入和土壤的进一步恢复。

English Abstract

In order to understand the roles of shrubs in the restoration processes of degraded vegetation in semiarid areas, we investigated the effects of shrubs on soil properties and community characterestics of herbaceous plants in Horqin Sand Land, Northern
China. Based on the field investigation and lab analysis, the plant community characterestics of herbaceous plants and soil physicochemical properties in outside and inside shrub canopies were studied in the restoration processes of degraded vegetation (mobile
dune, semi-mobile dune, semi-fixed dune and fixed dune). The results showed that the vegetation cover, plant height and density
were higher in inside than outside of Caragana microphylla shrub in mobile dune, semi-mobile dune, semi-fixed dune and fixed
dune, and community characteristics showed a declined trend from shrub inside to outside. The comparison of soil properties in outside and inside shrub canopies of Artemisia halodendrom, Caragana microphylla, Artemisia frigida, showed that the contents of soil
organic carbon, total nitrogen and phosphorus, available nitrogen and phosphorus at 0~10 cm depth were higher in inside than outside shrub canopies, which suggests that the development of shrubs can enrich the soil nutrient under shrubs on dunes. These results
suggest that the development of shrubs has an important role in protecting and restoring seed resource under shrubs and creates significant “islands of fertility”, supporting the benign environment for herbaceous plants invasion and establishment under shrubs