青海省大果圆柏群落物种多样性与土壤因子的关系

大果圆柏(Juniperus tibetica)群落是三江源地区主要森林群落之一，在保障中国水生态安全、保育生物多样性和延缓气候变化等方面发挥着重要作用。该研究以青海省果洛州班玛县大果圆柏天然群落为对象，通过野外调查和室内分析，以明确群落的物种组成，以及物种多样性与土壤因子的关系，为大果圆柏群落物种多样性保护和资源植物开发利用提供参考。结果表明：(1)大果圆柏群落内共有植物169种，隶属36科101属，其中菊科(Compositae)、蔷薇科(Rosaceae)和毛茛科(Ranunculaceae)植物物种最多，分别占总物种的14.20%、13.61%和9.47%。(2)大果圆柏群落的灌、草层物种多样性特征差异显著，草本层的丰富度(2.90)、多样性(2.35)和优势度指数(0.80)均高于灌木层丰富度(1.03)、多样性(1.45)和优势度指数(0.70)，而均匀度指数(0.79)低于灌木层(0.89)。(3)0~60 cm土层林地土壤有机质、全氮、全磷含量及pH均值分别为(87.54±20.32) g·kg^-1、(4.68±1.36) g·kg^-1、(0.83±0.18) g·kg^-1和6.73±0.51。(4)灌木层Margalef指数、Shannon Wiener指数与土壤有机质含量呈极显著正相关关系(P<0.01)；草本层Margalef指数、Shannon Wiener指数与土壤全钾含量呈显著负相关关系(P<0.05)，与土壤pH呈显著正相关关系(P<0.05)。研究认为，青海省大果圆柏林地土壤有机质、全钾含量和pH是影响群落物种多样性的主导因子。

Relationship between Species Diversity of Juniperus tibetica Community and Soil Factors in Qinghai Province

Juniperus tibetica community is one of the main forest communities in the Three River Headwaters, which plays vital roles in ensuring the safety of water ecology of China, conserving biodiversity, and mitigating climate change. Based on the natural J. tibetica community at Banma, Guoluo, Qinghai, we revealed the community species composition and the relationship between species diversity and soil factors through field investigation and indoor analysis. This study will provide references for species diversity protection and resource plants development and utilization. The results indicated that: (1) there are 169 species of plants in the J. tibetica community, belonging to 36 families and 101 genera. Among them, Compositae, Rosaceae and Ranunculaceae have the most species, accounting for 14.20%, 13.61% and 9.47% of the total number of species in the community. (2) There are significant differences in the species diversity characteristics of the shrub grass layer in the J. tibetica community, the Margalef (2.90), Shannon Wiener (2.35) and Simpson index (0.80) of the herb layer are higher than the Margalef (1.03), Shannon Wiener (1.45) and Simpson index (0.70) of the shrub layer, while the Pielou index (0.79) is lower than that (0.89) of the shrub layer. (3) The soil organic matter, whole nitrogen and whole phosphorus contents and pH mean value of 0~60 cm soil layer are (87.54±20.32) g·kg^-1, (4.68±1.36) g·kg^-1, (0.83±0.18) g·kg^-1 and (6.73±0.51), respectively. (4) Shrub layer Margalef index and Shannon Wiener index are extremely significant positively correlated with soil organic matter content (P<0.01). The Margalef index and Shannon Wiener index of the herb layer are significant negatively correlated with the total potassium content of the soil (P<0.05), and positively correlated with the pH value (P<0.05). Soil organic matter, total potassium contents and pH value are the key factors affecting the community species diversity.