澜沧黄杉(Pseudotsuga forrestiiCraib)为中国特有珍稀濒危植物,野外种群个体数量少,分布范围狭窄,研究其种群结构及动态特征可以量化种群未来发展趋势,并为科学合理保护该物种提供依据。通过对云南省迪庆州德钦县不同群落类型下澜沧黄杉种群的调查及数据收集,编制澜沧黄杉静态生命表,绘制存活曲线和生存分析函数曲线,并采用时间序列模型对种群的数量动态进行预测,以揭示不同群落环境下澜沧黄杉的种群结构和动态特征。结果表明:德钦县澜沧黄杉种群主要分布在海拔2200-3300m的区域,栖息地群落类型为澜沧黄杉林、冷杉林与云南松林,三种群落澜沧黄杉种群均属增长型,数量变化动态指数Vpi和Vpi'都大于0,但对外界干扰比较敏感,存活曲线趋于Deevey-Ⅱ型,表明种群各龄级的死亡率基本接近。不同群落类型下种群大小依次为澜沧黄杉林 ＞ 冷杉林 ＞ 云南松林,结合种群动态分析表明,澜沧黄杉林更适宜种群的生存;生存分析和时间序列预测表明幼龄个体的缺乏、死亡率高,是导致种群野外更新困难的主要原因。野外调查发现澜沧黄杉天然种群受到人类砍伐、放牧、开荒等因素的影响,严重影响了种群的生存,因此未来在加大科学研究力度进一步探究该物种濒危影响因素的同时,还要加大保护宣传力度,并扩大建立保护区以实现对该物种的多方位保护。
Pseudotsuga forrestii Craib is a unique, rare and endangered species in China, with small population and narrow distribution area. This study aims to quantify the future development trend of the population through population structure and dynamic characteristics analysis, which will provide scientific basis for reasonable protection of P. forrestii. Based on field investigation in Deqin County, Diqing Prefecture, Yunnan Province, the population data in different community types were collected. The static life table was established, survival curves and function curves were constructed, and the population dynamics were predicted by the time-sequence model. Results showed that P. forrestii mainly distributed in the area with altitude ranging from 2200 m to 3300 m in Deqin County. The forest types of P. forrestii population habitats were P. forrestii forest, Abies. spp forest and Pinus yunnanensis forest, respectively. Meanwhile, the population structure of P. forrestii in the three mentioned habitats showed growth type. The dynamic indices Vpi and Vpi' were larger than zero, but were sensitive to external disturbance. The population survival curves tended to be Deevey-Ⅱ type, which indicated that the mortality rate in different age classes was similar. Population size of P. forrestii in different forest types was P. forrestii forest > Abies. spp forest > Pinus yunnanensis forest. The above results suggested that P. forrestii forests were more suitable for the survival of P. forrestii population. Furthermore,the survival analysis and the time-sequence model demonstrated that lack of young individuals and high mortality rate resulted in the difficulty of population regeneration in the field, which could be the major cause for P. forrestii population declines. Through field investigation, we found that anthropogenic disturbances including grazing, tree felling and farming severely affected the survival of P. forrestii population. Therefore, we suggested that scientific research is needed to further explore the factors affecting the survival of P. forrestii. Additionally, strengthening the communication capacity and expanding protected areas could contribute to achieve the multi-directional protection of the studied species.