海南吊罗山濒危植物美丽火桐种群结构与动态特征

Population structure and dynamic characteristics of endangered plant Firmiana pulcherrima in Diaoluo Mountain of Hainan Province

关键词:  美丽火桐，种群结构，静态生命表，生存分析，时间序列预测

Key words:  Firmiana pulcherrima, population structure, static life table, survival analysis, time sequence analysis

摘要:

美丽火桐（Firmiana pulcherrima）是中国特有种和国家II级重点保护野生植物，自然分布于海南中部热带雨林区。为摸清美丽火桐种群生存现状和发展趋势，探究导致其濒危的主要原因，该文对吊罗山美丽火桐天然种群进行了野外调查。以空间代替时间构建种群龄级结构，通过静态生命表、动态量化分析等方法分析该种群结构特征和动态变化规律，并采用时间序列模型预测种群未来发展潜力。结果表明：（1）美丽火桐种群为增长型种群，数量动态变化指数Vpi＞V′pi＞0，种群对完全随机干扰所承担的最大风险概率Pmax为1.82%，种群龄级结构完整，抗干扰能力弱，增长性和稳定性差。（2）该种群生命期望在第II龄级达到最大值，后随龄级增加而减小，死亡率和消失率均在第I、VII和IX龄级有峰值，存活曲线为Deevey-III型。（3）生存分析表明该种群具有早期锐减、中后期趋于稳定的特点。（4）经过未来3个、6个、9个龄级时间后，除第IV和第VIII龄级外，其余龄级个体数均有增多，种群自然更新良好。研究表明，强烈的光环境筛和种内种间竞争是导致吊罗山美丽火桐种群濒危的主要原因，建议采取适度间苗和修枝、强化种群及生境保护、积极开展人工繁育及回归种群扩充等措施，保育美丽火桐种群增长和促进种群恢复。

Abstract:

Firmiana pulcherrima is not only an endemic species in China but also a national grade second-level key protected?plant. It is naturally distributed in the tropical rainforest area of central Hainan. To explore the survival status, development trend and the main reasons for its endangerment of the population, this paper conducted a field investigation on the natural population of F. pulcherrima in Diaoluo Mountain. The age-class structure of the population was constructed by replacing time with space. The population structure characteristics and dynamic change rules were analyzed through methods such as static life table and dynamic quantitative analysis, and the future development potential of the population was predicted by time series model. The results were as follows: (1) The population of F. pulcherrima was a growing type. The number dynamic index of entire population structure when ignoring external interference Vpi is greater than the number dynamic index of entire population structure when considering external interference V′pi, and both are greater than 0. The maximum risk probability of population to completely random disturbance Pmax was 1.82%. The population has a complete age structure, weak anti-interference ability, poor growth and stability. (2)The life expectancy of the population reached the maximum at the second age class, and then decreased with the increase of age class. Mortality and vanish rates peaked at age I, VII and IX. The survival curve was Deevey-III type. (3)Survival analysis showed that the population decreased sharply in the early stage and tended to be stable in the mid-late stages. (4)After 3,6 and 9 age classes in the future, the number of individuals in the remaining age classes increased except for the IV and VIII age classes. The population has strong natural regeneration ability. Consequently, strong light environment screening and interspecific competition are the main reasons for the endangerment of F. pulcherrima. It is suggested to take measures such as moderately thinning and pruning, strengthening population and habitat protection, actively carrying out artificial breeding and returning population expansion to promote the growth and recovery of the population.