Abstract: Exploring the ecological niches and interspecific associations of dominant herbaceous species under different types of Platyladus orientalis plantations in Beijing mountain area would help to provide scientific references for the establishment and management of artificial forests in the Beijing-Tianjin Sandstorm Source Control Project. In this study, the examination was carried out on the niche width, niche overlap, overall association and interspecific association of dominant herbaceous species in the understory of different types of Platyladus orientalis plantations as the pure Platyladus orientalis forest (C1), the mixed Platyladus orientalis-Pinus tabuliformis forest (C2) and the mixed Platyladus orientalis-Cotinus coggygria var. cinereus forest (C3). The findings included the following:There was no significant qualitative relationship for the orderings on the niche widths and the importance values among all studied herbaceous species. Rubia cordifolia was the dominant herb co-existed in those three forest types, and the degree of ecological niche overlap with other herbs was >0.90. The overall association test showed that the herbaceous species in C2 forest were significantly positively correlated, the herbaceous species in C3 forest were significantly negatively correlated, and those in C1 forest was not significantly positively correlated. Additionally, there was a strong positive association between the dominant herbaceous species in the understorey of C2 forest, whereas a strong negative association was observed among dominant herbaceous species in the understorey of C3. Artemisia annua-Thalictrum aquilegiifolium var. sibiricum, Rubia cordifolia-Cynanchum rostellatum, etc. showed a strong connectivity and had large ecological niche overlap values, indicating their robust habitat adaptability within Platyladus orientalis forests in Beijing mountain area.

Key words: Beijing mountain area, Platyladus orientalis artificial forest, Dominant herbaceous species, Niche, Interspecific association

摘要： 探究北京山区不同类型侧柏人工林下优势草本的生态位和种间关联性，为京津风沙源工程人工林营造与管理提供参考，本研究以侧柏（Platycladus orientalis）纯林（C1）、侧柏-油松（Pinus tabuliformis）混交林（C2）和侧柏-黄栌（Cotinus coggygria var. cinereus）混交林（C3）为研究对象，对不同类型林下优势草本生态位宽度、生态位重叠度、总体关联性和种间联结性进行研究。结果表明：生态位宽度排序与重要值排序无显著定性关系；茜草（Rubia cordifolia）是3种林分类型共有的优势草本，与其他草本的生态位重叠程度大于0.90；总体关联性检验表明，C2为显著正关联，C3为显著负关联，C1为不显著正关联；此外，C2林下优势草本种间正联结性强，而C3林下优势草本种间负联结强。黄花蒿（Artemisia annua）-唐松草（Thalictrum aquilegiifolium var. sibiricum）、茜草-萝藦（Cynanchum rostellatum）等种对联结性强、生态位重叠值大，在北京山区侧柏人工林下具有较强的生境适应性。

关键词: 北京山区, 侧柏人工林, 优势草本, 生态位, 种间联结性