He Chun-Mei, Liu Run-Qing, Yang Zhi-Chun, Yin Qiu-Long, Jia Shi-Hong, Luo Ying, Hao Zhan-Qing
School of Ecology and Environment, Northwestern Polytechnical University, Xi'an 710129, China.
Ying Yong Sheng Tai Xue Bao. 2021 Aug;32(8):2737-2744. doi: 10.13287/j.1001-9332.202108.001.
The Qinling Mountain is a natural boundary between warm temperate zone and subtropical zone. While the China Forest Biodiversity Monitoring Network (CForBio) have basically covered most of the climate regions in China, few plots were located in the climate transition zone. Following the field protocol of CForBio and the Center for Tropical Forest Science (CTFS), a 25 hm(500 m×500 m) forest plot was established in Huangguan Nature Reserve in Shaanxi Province, China, in 2019. In this study, we analyzed species composition, flora characteristics, diameter class structure, and spatial distribution patterns of dominant tree species based on the data of all woody species with a diameter at breast height (DBH) ≥1 cm. The results showed that there were 75137 woody individuals with DBH ≥1 cm in the plot (95679 when including branching individuals), belonging to 121 species, 83 genera and 44 families. The flora type at the genera level was mainly temperate, accounting for 71.1% of the total genera, and mixed with some tropical components. The dominant species in the community were obvious, with the number of individuals in the top 5 species exceeding 40% of the total number of individuals, the number of individuals in the top 50 species accounting for 95% of the total number of individuals, and the number of individuals in the remaining 61 species being less than 5% of the total. The diameter distribution of all woody indivi-duals in the plot was inverted 'J' type. Spatial distribution patterns varied across the four most abundant species with importance value >5. The degree of aggregation within species decreased with the increases of scales, while the spatial distribution of different species was affected by environmental heterogeneity. Warm-temperate deciduous broadleaved forest in Qinling Mountains had abundant species, stable community structure and good regeneration, reflecting the typical characteristics of the transition from warm temperate zone to subtropical zone. Environmental heterogeneity might be an important factor affecting the spatial distribution of tree species in the plot.
秦岭是暖温带和亚热带的天然分界线。虽然中国森林生物多样性监测网络（CForBio）已基本覆盖了中国的大部分气候区域，但位于气候过渡带的样地却很少。按照CForBio和热带森林科学中心（CTFS）的野外调查规程，2019年在中国陕西省皇冠自然保护区设立了一块25公顷（500米×500米）的森林样地。在本研究中，我们基于胸径（DBH）≥1厘米的所有木本植物数据，分析了优势树种的物种组成、植物区系特征、径级结构和空间分布格局。结果表明，样地内胸径≥1厘米的木本植物个体有75137株（包括分枝个体则为95679株），隶属于44科83属121种。属级水平的植物区系类型以温带为主，占总属数的71.1%，并混有一些热带成分。群落中的优势种明显，前5个物种的个体数超过个体总数的40%，前50个物种的个体数占个体总数的95%，其余61个物种的个体数占比不到总数的5%。样地内所有木本植物个体的直径分布呈倒“J”型。重要值>5的4种最丰富物种的空间分布格局各不相同。物种内的聚集程度随尺度增加而降低，而不同物种的空间分布受环境异质性影响。秦岭暖温带落叶阔叶林物种丰富，群落结构稳定，更新良好，体现了从暖温带向亚热带过渡的典型特征。环境异质性可能是影响样地内树种空间分布的重要因素。
