托木尔峰国家级自然保护区天然吐鲁番锦鸡儿种群结构与动态特征

Population structure and dynamic characteristics of the natural Caragana turfanensis in the Tomur Peak National Nature Reserve

关键词:  吐鲁番锦鸡儿, 种群结构, 静态生命表, 存活曲线, 生存分析

Key words:  Caragana turfanensis, population structure, static life table, survival curve, survival analysis

摘要:

吐鲁番锦鸡儿(Caragana turfanensis)是我国天山山脉特有的近危植物。为阐明其种群的生存现状与发展趋势,该文以托木尔峰国家级自然保护区吐鲁番锦鸡儿的天然种群为调查对象,通过样方调查与种群统计学方法,编制静态生命表、拟合存活曲线并结合种群生存力及动态量化指数进行系统评估。结果表明:(1)种群年龄结构呈“倒J型”,幼苗和小龄占比较高,具增长型特征,但龄级分布不均。(2)种群存活曲线符合Deevey-II型中的B3亚型,早期死亡率极高(I龄级高达90.5%),显示强烈的环境筛选作用。(3)生存分析表明,种群生存率随龄级增加急剧下降(到III龄级仅有0.9%),累计死亡率在III龄级已达99.1%,龄级越大死亡率越高。(4)种群动态指数分析表明,吐鲁番锦鸡儿各龄级动态指数均大于零,种群呈增长态势。然而,其V'_pi值(3.14%)趋近于零,表明在自然干扰下增长极为缓慢。种群随机干扰风险极大值(P_max)为0.04%,表明种群对环境干扰的抵抗能力较弱,具有较高的生态脆弱性。综上认为,吐鲁番锦鸡儿种群虽具增长潜力,但极高的早期死亡率导致了严重的“幼苗瓶颈”,种群稳定性较差。建议通过微生境改良、建立保护小区及加强人工辅助更新等措施,以突破种群早期生存瓶颈,促进种群恢复与稳定。

Abstract:

Caragana turfanensis is a near-threatened plant endemic to Tianshan Mountains of China. To clarify the survival status and developmental trends of its populations, this study investigated the natural populations of C. turfanensis in the Tomur Peak National Nature Reserve. Using quadrat surveys and population statistical methods, we compiled a static life table, fitted survival curves, and conducted a systematic assessment combined with population viability and dynamic quantitative indices. The results were as follows:(1)The population exhibited an “inverted J-shaped” age structure, with a high proportion of seedlings and young individuals, indicating an expanding growth pattern, yet the age-class distribution was uneven.(2)The survival curve conformed to the B3 subtype of the Deevey Type II curve, characterized by extremely high early mortality(up to 90.5% in age class I), reflecting strong environmental filtering.(3)Survival analysis revealed that the survival rate declined sharply with increasing age class(dropping to only 0.9% by age class III), with cumulative mortality reaching 99.1% by age class III, indicating increasing mortality in older classes.(4)Population dynamic index analysis indicated that the dynamic indices of all age classes of C. turfanensis were positive, reflecting an overall increasing population trend. However, the V'_pi value(3.14%)was close to zero, implying extremely slow growth under natural disturbances. The maximum risk value of random disturbance for the population(P_max=0.04%)demonstrated weak resistance to environmental interference and high ecological vulnerability. In conclusion, although C. turfanensis populations possess growth potential, the extremely high early mortality causes a severe “seedling bottleneck”, resulting in poor population stability. It is recommended to implement measures such as microhabitat improvement, establishment of protected micro-reserves, and enhancement of artificial assisted regeneration to break through the early survival bottleneck and promote population recovery and stability.