Population structure and dynamic characteristics of an endangered plant species (Berchemiella wilsonii) and its variety (Berchemiella wilsonii var. pubipetiolata) postprint

Abstract: Understanding population structure and dynamic characteristics of rare and endangered species is crucial for providing theoretical bases for their conservation and management. In this study, we conducted field investigations of an endangered plant species (Berchemiella wilsonii) and its variety (B. wilsonii var. pubipetiolata) across their entire distribution ranges in China, including Hubei, Anhui, and Zhejiang provinces. We drew the population structure diagrams and designed the static life tables. Subsequently, we fitted and plotted survival curves for survival analysis and used time series model to predict the population development trends. The results were as follows: (1) The age class structure of B. wilsonii was irregular pyramid mold and that of B. wilsonii var. pubipetiolata was a spindle-shaped structure. (2) The survival curves of the two species tended to be the Deevey-III type, indicating the high mortality rate at the juvenile stage. For both species, the mortality rate reached the peak at the age class VI. (3) The survival rate and cumulative mortality rate showed that B. wilsonii entered the declining stage earlier than B. wilsonii var. pubipetiolata. (4) The dynamic index suggested that populations of these two species are increasing, but they are sensitive to external disturbance. (5) Time series prediction indicated that the number of individuals at each age class of B. wilsonii will increase with uneven degrees after the next 2, 4, 6 and 8 age classes. However, the number of young-, middle-, and mature-aged individuals of B. wilsonii var. pubipetiolata will disappear, decrease and increase in the future, respectively. Therefore, we should adopt different conservation strategies for the two species. For B. wilsonii, appropriate forest thinning should be carried out to improve light conditions, and human disturbance should be reduced to promote the seedling survival. For B. wilsonii var. pubipetiolata, it is necessary to strengthen research on artificial propagation technology and supplement the seedlings timely in the wild to alleviate population decline.