Population structure and dynamic characteristics of Ormosia microphylla in geomancy forest of Gutian Meeting Site in Fujian
The population of the rare and endangered plant Ormosia microphylla Merr.et H.Y.Chen in 77 sample plots of geomancy forest of Gutian Meeting Site in Fujian was investigated,and the population structure and dynamic characteristics of this population were analyzed.The results show that there are a total of 273 O.microphylla individuals in 77 sample plots,based on height(h)and diameter at breast height(DBH),they can be divided into 10 diameter classes,among which the seedling individuals of class Ⅰ(h≤50 cm)are the most(112),but the mortality rate from class Ⅰ to class Ⅱ(50 cm＜h≤100 cm)is 60.7％,indicating that the individual survival ability of seedlings is poor;the growth status from sapling to small tree stage[class Ⅱ to class Ⅴ(10 cm≤DBH＜15 cm)]is relatively stable,but only a few individuals can survive from medium tree to large tree stage[class Ⅳ(15 cm≤DBH＜20 cm)to class X(DBH ≥ 35 cm)],and the individual number gradually decreases in general;in terms of height class structure,the individuals of O.microphylla population is distributed across all 7 height classes,demonstrating a certain degree of integrity and stability.The dynamic index(Vpi)of O.microphylla population is 40.67％,the random disturbance dynamic index(Vpi')is 1.36％,and the random disturbance risk probability(Pmax)is 3.33％,indicating that the O.microphylla population is a growing population,but the growth is not obvious,and its ability to resist disturbances is relatively weak.The survival curve of O.microphylla population tends to be of B,subtype of Deevey-Ⅱ type;with the increase of diameter class,the overall survival rate function[S(t)]of O.microphylla population shows a tendency to decrease,while the cumulative mortality rate function[F(t)]shows a tendency to increase,and the death density function[f(t)]and hazard rate function[λ(t)]of O.microphylla population evidently increase from class Ⅵ(5 cm ≤DBH＜10 cm)to class Ⅴ,indicating a trend towards population decline.The time-series prediction result shows that,in general,after the next 2,4,6,and 8 diameter class time,the number of individuals at each diameter class of O.microphylla population will increase,indicating a good potential for population development.The comprehensive research results indicate that the O.microphylla population shows a growth tendency overall,but the stability and resistance are relatively weak,and the weak ability of O.microphylla to resist disturbances and its disadvantage in competing for resources are the main reasons for limiting its population growth and causing poor population stability.It is recommended to adopt in situ conservation and simultaneously increase the number of individuals through means including appropriate thinning and fertilization,and enhanced seed cultivation to improve the competitiveness and stability of population.
Ormosia microphylla Merr.et H.Y.Chenpopulation structurestatic life tablesurvival curvesurvival analysis
万方数据
维普
