Zhang Wei, Jiao Zi-wei, Shang Tian-cui, Yang Yun-fei
Ying Yong Sheng Tai Xue Bao. 2015 Apr;26(4):1091-8.
Juglans cathayensis is an endangered plant species and listed as a class II protected species of the national government of China. In order to grasp the current state of J. cathayensis populations and predict the population dynamics in the future, a large-sample investigation was conducted in the sample plots along different altitude gradients in four valleys in J. cathayensis conservation area. According to the diameter at breast height (DBH) class of the trees, the age class structures of the populations were analyzed, and static life tables for J. cathayensis populations in different habitats along the altitude gradient was constructed by smoothing out technique, and comparative fluctuations cycles of the populations in different habitats were carried out by spectral analysis. The results showed that DBH decreased gradually with the increasing altitude. The population was composed of 19 age classes in the low-altitude habitat (1241 - 1380 m) with the maximum DBH of 91.7 cm, 18 age classes in the middle-altitude habitat (1381 - 1490 m) with the maximum DBH of 82.8 cm, and 13 age classes in the high-altitude habitat (1491 - 1670 m) with the maximum DBH of 58.9 cm. Life expectancies of J. cathayensis populations were fluctuant for the same age class at different altitudes and for different age classes at the same altitude. In the three altitude-different habitats, the survival curves of the populations trended toward Deevey- II type and the age structures of the populations were expanding. The curves of mortality showed three peaks, and the mortality rates of 9 age classes at 1241 - 1380 m and 1491 - 1670 m above sea levels were the highest, being 55.9% and 89.8%, respectively, and the mortality rate of 12 age classes at 1381 - 1490 m above sea level was the highest (79.4%). The population dynamics was significantly affected by the fundamental wave of biological characteristic throughout the life cycle of J. cathayensis population, and small cycles of multi-harmonic superposition with large cycles were presented. J. cathayensis is a long lifespan tree and a major dominant species in this conservation area. The natural regeneration of its current populations is good. If not strong anthropogenic disturbances or severe natural disasters, J. cathayensis would maintain the dominant position in the community.
野核桃是一种濒危植物物种，被列为中国国家二级保护植物。为掌握野核桃种群现状并预测未来种群动态，在野核桃保护区四个山谷不同海拔梯度的样地进行了大样本调查。根据树木的胸径等级，分析了种群的年龄结构，运用平滑技术构建了沿海拔梯度不同生境下野核桃种群的静态生命表，并通过谱分析对不同生境种群的波动周期进行了比较。结果表明，胸径随海拔升高逐渐减小。低海拔生境（1241 - 1380米）种群由19个年龄级组成，最大胸径为91.7厘米；中海拔生境（1381 - 1490米）有18个年龄级，最大胸径为82.8厘米；高海拔生境（1491 - 1670米）有13个年龄级，最大胸径为58.9厘米。野核桃种群在不同海拔相同年龄级以及相同海拔不同年龄级的预期寿命存在波动。在三个不同海拔生境中，种群存活曲线趋向于迪维 - II型，种群年龄结构呈增长型。死亡率曲线呈现三个峰值，海拔1241 - 1380米和1491 - 1670米处9个年龄级的死亡率最高，分别为55.9%和89.8%，海拔1381 - 1490米处12个年龄级的死亡率最高（79.4%）。在野核桃种群的整个生命周期中，种群动态受生物特性基本波动的显著影响，并呈现出大周期与多谐波叠加的小周期。野核桃是长寿树种，也是该保护区的主要优势种。其当前种群的自然更新良好。若没有强烈的人为干扰或严重的自然灾害，野核桃将在群落中保持优势地位。
