Abstract:

This study investigates the survival status and causes of endangerment of the wild population of the Heritiera parvifolia in Diaoluo Mountain,key protected wild plant of rational importance located within Hainan Tropical Rainforest National Park.The study analyzed and predicted population structure and dynamics using diameter class,the quantity dynamic index,static life table,survival curve,survival function,and time series prediction model.The results show that:1)The age class structure of Heritiera parvifolia population indicated an increasing trend.However,a 32.58% decline was observed from the age classes of Ⅱ to III,suggesting recruitment limitation.2)The quantity dynamic index(V₇)was -0.666 7 between the VII and VIII age classes.This suggested a higher risk of decline among older individuals.Additionally,the non-interference dynamic index(V_pi),random interference dynamic index(V'_pi) and random interference risk probability(P_max)were all greater than zero,with V_pi significantly exceeding V'_pi. This highlights the population’s sensitivity to external disturbances.3)The life expectancy(e_x)peaked at age class III,and the survival curve resembled a Deevey-Ⅱ type.4)Survival functional analysis revealed a pattern of early-stage decline,significant fluctuations in the middle stage,and gradual decline in the later stages of the Heritiera parvifolia population.5)Projections for the next 2,4,6 and 8 age classes in the future indicate varying degrees of decline in individuals within age classes II and VIII.The primary factors contributing to the endangerment of Heritiera parvifolia include low seedling survival rates,intense intra and interspecific competition,heightened risk of decline among older individuals,and human disturbances.

Key words: Heritiera parvifolia, national key protercted wild plants, age structure, survival function, time series prediction