濒危植物秦岭冷杉地理分布和生物生态学特性研究

Distribution and bio-ecological characteristics of Abies chensiensis, an endangered plant

秦岭冷杉 (Abieschensiensis)为中国特有三级保护植物 ,仅岛屿化分布于陕西、甘肃、四川、河南的秦巴山地和湖北神农架中高山地区 ,分布海拔 130 0 - 2 30 0m。为了对秦岭冷杉种群进行深入研究和有效保护 ,通过样地调查和相关资料分析 ,对其地理分布、群落特性、种群特性进行了系统研究。秦岭冷杉群落包含种子植物 4 0科 6 3属10 2种 ,可划分成 11个地理区系成分 ,其中温带分布型属占 84 .2 1% ,热带分布型属占 15 .79% ,温带分布是群落的基本特性。秦岭山区的秦岭冷杉群落可分为 5个群丛 ,基本特点为 :生境阴湿 ;群落郁闭度大 ,结构复杂 ;种群个体年龄差异大 ;天然更新主要发生在保护较好的阴坡林窗地段。秦岭冷杉苗期生长缓慢 ,在 30 - 70年龄阶段 ,高生长旺盛 ;在 4 0 - 10 0年龄阶段 ,胸径生长较快。秦岭冷杉开始结实年龄在 30 - 4 0年龄阶段 ,结实间隔期为 3- 5年。秦岭山区成熟个体平均产球果 8个 /株 ,饱满种子 5 6粒 /球果。种群更新的关键问题是种子产量低 ,林下幼苗稀疏 ,更新缺乏后继资源。种子向幼苗转化率低是生活史中的脆弱环节。在未来经营保护中 ,应以就地保护为主 ,通过抚育管理 ,促进天然更新 ;丰年应适时采种 ,就地育苗 ,扩大人工种群。

Qinling fir, Abies chensiensis, is endemic to China and was listed in the China Plant Red Data Book as one of the third class protected plants. It is only found scattered in small forest fragments in Mts. Qinling, Bashan and Shennongjia from 1300 m to 2300 m a. s. l. in Shaanxi, Gansu,Henan, Sichuan and Hubei provinces. To assist in efforts to effectively conserve and restore this species, the geographic distribution, community structure and demographic characteristics of populations were studied through field investigations and statistical analysis. In the A. chensiensis communities in the Qinling Mountains, we recorded 102 plant species, belonging to 63 genera and 40 families. Among them, the temperate geographical elements comprise 84.21%, and the tropical geographical elements 15.79%. The communities in Qinling could be divided into five associations by cluster analysis on the importance values of the dominant species. The habitat of the communities was wet and shaded, and the coverage was relatively high. The structure of the communities was complex, and the age difference among individuals was significant. The natural regeneration of this species occurred mainly in canopy gaps on shaded slopes. The growth of young seedlings was relatively slow, but DBH increased relatively quickly during the 40-100 years stage, as did height during the 30-70 years stage. The sexual reproduction for this A. chensiensis population began at 30-40 years old, and the seed-bearing interval was about 3-5 years. Mature trees of A. chensiensis produced on average eight cones, and the mean number of seeds per cone was 56. The lack of seedlings was the main barrier for regeneration of this species. Insufficient seeds and low survival rate from seed to seedling were the weak link. In the future, in situ conservation should be considered as the most important management activity for this species, and natural regeneration should be promoted. At the same time, the artificial populations should be expanded from seeds collected in years of high seed set.