铁心杉种群结构与动态特征

Population structure and dynamic characteristics of Iron-heart Cunninghamia lanceolata

【目的】杉木是南方生长最快的主要树种之一,而铁心杉是心材比例高、具有防腐的特殊性质的杉木新品种,但其野生种群分布范围窄。研究铁心杉种群结构与动态特征,可以为铁心杉种群的恢复以及种质资源的培育提供理论基础。【方法】以湖南小溪国家级自然保护区小溪乡的铁心杉天然林为研究对象,通过实地调查以胸径代替龄级,制作年龄结构图;以静态生命表制作存活、死亡和消失率曲线;以生存函数估计值制作生存函数曲线;计算了种群动态变化指数;预测了种群数量的时间序列。【结果】1)铁心杉种群的龄级结构属于不规则金字塔形,种群有一定的更新能力,第Ⅰ龄级储备丰富,但幼龄阶段死亡率高,铁心杉种群存活曲线趋Deevey-Ⅲ型;2)铁心杉种群在整个龄级中的死亡率和消失率曲线走向一致,在第XIII龄级出现最大值,而第Ⅰ龄级次之,因此铁心杉种群的更新和结构受到了空间资源的限制;3)经过生存分析,发现铁心杉的生存能力相对较差,在早期阶段会出现剧烈的下降,中期保持稳定,后期则会出现衰退;4)时间序列分析显示,整个铁心杉种群向中、高龄级集中,低龄的缺失会导致种群衰退。【结论】应尽快确定铁心杉的生态学地位,并采取就地保护以确保种群的更新;同时建议通过组织培养、引种栽培来保护铁心杉种质资源,扩大其分布范围。

【Objective】Cunninghamia lanceolata is one of the fastest growing major tree species in south China,and Iron-heart Cunninghamia lanceolata is a new cultivar with high heart-wood ratio and special characteristics of anti-corruption,but its wild population distribution range is narrow.The study of the population structure and dynamic characteristics of Iron-heart C.lanceolata can provide a theoretical basis for the restoration of Iron-heart C.lanceolata population and breeding of germplasm resources.【Method】In this study,the hemaceria natural forest in Xiaoxi Township,Hunan Xiaoxi National Nature Reserve was selected as the research object.By conducting field investigations and replacing age groups with chest diameter,an age structure map was created;The survival,death and disappearance rate curves were made with the static life table;The survival function estimated value was used to make the survival function curve;The population dynamic change index was calculated;Predicted the population quantity time series.【Result】1)The age class structure of the population belonged to the irregular pyramid type,the population had a certain renewal ability,the reserves of theⅠage class were abundant,but the mortality in the young stage was high,and the survival curve of the population trended to Deevey-Ⅲtype;2)The mortality and disappearance rate curves of the Iron-heart C.lanceolata population were consistent throughout the entire age class,with a maximum value appearing at the XIII age class,followed by the I age class.Therefore,the renewal and structure of the Iron-heart C.lanceolata population are limited by spatial resources;3)After survival analysis,it was found that the survival ability of Iron-heart C.lanceolata was relatively poor,with a severe decline in the early stage,stability in the middle stage,and decline in the later stage;4)Time series analysis showed that the whole Iron-heart C.lanceolata population concentrates to the middle and old age.The lack of low age will lead to population decline.【Conclusion】We should quickly determine the ecological status of Iron-heart C.lanceolata and adopt on-site protection to ensure population renewal;At the same time,it is recommended to protect the germplasm resources of Iron-heart C.lanceolata through tissue culture and introduction cultivation,and expand its distribution range.