宝天曼国家级自然保护区锐齿槲栎林短期动态变化

Short-term dynamic change of Quercusaliena var.acuteserrata forest in Baotianman National Nature Reserve

为进一步了解宝天曼国家级自然保护区优势种群的动态变化,以宝天曼自然保护区1 hm2(100 m×100 m)的锐齿槲栎(Quercus aliena var.acuteserrata)林样地为长期定点监测对象,对2009和2014年2次调查数据进行分析,比较主要物种的补员和死亡状况,研究群落的更新特点。结果表明,(1)本样地内主要物种的年均补员率为2.64%,年均死亡率为4.56%,样地中补员个体数最多的是四照花(Dendrobenthamia japonica var.chinensis),占24.76%。(2)锐齿槲栎数量最多,平均胸径(Diameter at breast height,DBH)增加量最大,由17.83 cm增加到21.53 cm。(3)10~15 cm径级个体死亡率最高,达40.97%;补员个体都分布在小径级(DBH≤5 cm)。(4)样地的胸高断面积由40.87增至41.51 m2·hm-2。锐齿槲栎的增量最大,为0.85 m2·hm-2。白桦(Betula platyphylla)减少得最多,达0.21 m2·hm-2。5年间,样地内树木总体在减少,大多数物种的平均胸径都在增加,随着径级增加,个体死亡率呈不完整的倒“U”型分布,群落个体径级分布整体呈倒“J”型。

To further understand the dynamics of dominant populations in Baotianman National Nature Reserve,a sample plot(100 m×100 m)of Quercus aliena var.acuteserrata forest was selected and monitored in Baotianman National Nature Reserve.The data of two surveys in 2009 and 2014 were analyzed to compare the recruitment and death status of main tree species and to study the regeneration characteristics of the community.The results showed that(1)the mean annual recruitment rate and mortality was 2.64%and 4.56%,respectively.Dendrobenthamia japonica var.chinensis had the largest number of supplementary individuals,accounting for 24.76%of the whole plot;(2)Quercus aliena var.acuteserrata had the largest number of individuals and the largest DBH increase(from 17.83 to 21.53 cm);(3)the DBH class(10~15 cm)had the highest mortality,reaching 40.97%,and the smallest DBH class(DBH≤5 cm)contributed all the recruitments in this plot;(4)the whole basal area(BA)of this plot increased from 40.87 to 41.51 m2·hm-2.Quercus aliena var.acuteserrata had the largest BA increment,reaching 0.85 m2·hm-2,while Betula platyphylla showed the greatest reduction of 0.21 m2·hm-2.On the whole,there was a decreasing trend with individuals,and a growth trend in DBH of most population in this plot.With diameter at breast height increasing,the individual mortality showed an incomplete inverted“U”type,while DBH classes showed an overall inverted“J”type.