秦岭落叶阔叶林25 ha森林动态监测样地物种组成与群落特征

秦岭落叶阔叶林是温带-亚热带过渡区保存较好的植被类型, 群落结构复杂。为了研究该过渡区植被的生物多样性维持机制, 按照CTFS (Center for tropical Forest Science)和中国森林生物多样性监测网络(CForBio)的建设标准, 于2015年在陕西省佛坪国家级自然保护区的落叶阔叶林建立了一块面积25 ha的动态监测样地。本文对样地内胸径(DBH) ≥ 1 cm的所有木本植物进行了调查和统计, 分析了其物种组成、区系特征、径级结构和空间分布格局。结果表明: 样地内DBH ≥ 1 cm的木本植物独立个体有47,739株, 隶属于36科66属119种。温带区系成分的科和属分别占总科数和总属数的41.18%和60.00%, 温带区系特征明显。稀有种有51种, 占总树种的42.86%。落叶树种有106种, 占总树种的89.07%, 在样地内占绝对优势。重要值≥ 1的物种共有20个, 分别占样地总个体数和总胸高断面积的70.35%和57.41%, 重要值最大的物种分别是乔木层的锐齿栎(Quercus aliena var. acutesrrata)、亚乔木层的水榆花楸(Sorbus alnifolia)和灌木层的刺叶栎(Q. spinosa)。样地内所有个体的平均胸径为8.61 cm, 整体径级分布呈倒”J”型, 小径级个体较多, 群落更新良好。除了太白杨(Populus purdomii), 样地内优势种表现出大尺度的聚集分布, 且它们的分布与生境紧密相关, 不同物种表现出不同的生境偏好。

Species composition and community characteristics of a 25 ha forest dynamics plot in deciduous broad-leaved forest,Qinling Mountains,north-central China

The deciduous broad-leaved forests in the warm temperate-subtropical transition zone of the Qinling Mountains are well preserved. The forests lie in the transition zone from warm temperate to subtropical forests and have a relatively complex community structure. Few studies have been conducted to investigate community structure based on a large-sized plot in this transitional region. This study analyzed species composition and community characteristics within a 25 ha plot, serving as the baseline information for monitoring long-term forest dynamics and diversity in the future. Based on the field protocol of the Center for Tropical Forest Science (CTFS) and the Chinese Forest Biodiversity Monitoring Network (CForBio), a 25 ha deciduous broad-leaved forest plot was established in the temperate-subtropical transition zone. All free standing trees with diameter at breast height (DBH) ≥ 1 cm were tagged, measured and identified to species. A total of 47,739 woody individuals with DBH ≥ 1 cm belonging to 119 species, 66 genera and 36 families were identified. The families and genera of temperate floristic elements accounted for 41.18% and 60.00%, respectively and were the dominant flora in this plot. Fifty-one rare species accounted for 42.86% of the total individuals. Deciduous trees species were dominant accounting for 89.07% of the total species. The 20 species with importance values ≥ 1 contributed 70.35% and 57.41% to the total number of individuals and the total basal area, respectively. The three most abundant species were Quercus aliena var. acutiserrata in the canopy layer, Sorbus alnifolia in the sub-tree layer, and Quercus spinosa in the shrub layer. The mean DBH of all individuals in the plot was 8.61 cm, and the overall structure of DBH size class of all individuals generally shows an inverse “J” type which indicated successful regeneration. All the dominant species exhibited large-scale aggregated spatial distribution closely related to habitat preferences except for Populus purdomii.