There is no trouble in the eighth day of the first month
Edit丨No worries about the eighth day of the first month
In this study, the distribution of existing garlic germplasm resources in Funing County, Yunnan Province was investigated, and 8 sample plots of Zhisang Township and Banlun Township, Funing County, where the distribution of wild resources was most concentrated, were taken as the study area.
The age structure, dynamic characteristics of population structure and future development trend of garlic fruit population in the two regions were studied by using the combination of sample method and field measurement method.
The results showed that the primary vegetation of garlic fruit had the typical characteristics of evergreen broad-leaved forest in monsoon forest, and the main population structure was composed of garlic fruit + Quercus japodia + Rubus rubus + Arrow bamboo + Golden Meal Fern + Miscanthus pentiflora.
Characteristics of plant population structure change
Population structure is a popular research topic in population ecology, and it is an important entry point for studying the mutual adaptation and selection of plant populations and the environment, which can comprehensively reflect the ecological process of the community and understand the succession law and future development trend of the community.
The age structure of the population can well reflect the changes in population size and the relationship between population and environment, and reveal the dynamic change characteristics of population.
Based on the analysis of static life tables, survival function curves and time series prediction models, the age structure and dynamic trend of garlic fruit population can be intuitively reflected.
In recent years, there have been many studies on the population structure and dynamic characteristics of endangered plants, such as C. microflora, Pinus yunnanensis, Taxus chinensis, and Tibetan sea buckthorn.
The results show that the number of individuals in the lower age class of these endangered plants fluctuates greatly, the number of individuals dies more, and the age class declines, so it is necessary to reduce human interference, improve the seed germination rate of the species, and increase the number of seedlings.
Garlic fruit is an endemic monogenus species only distributed in Funing, Guangnan and western Guangxi in southeast Yunnan, China, and is a national second-class rare and endangered protected tree species.
In the morphological dissection of garlic fruit, it was found that it had both primitive traits and very evolved traits, indicating that the related traits of garlic fruit are of great value for the study of the classification system of A. ferrophyllaceae.
According to statistics, there are about 40,000 wild garlic fruit plants left in the country. Garlic fruit is an ancient woody oil plant due to its kernel oil yield of up to 65%.
Oils and fats contain up to 45% nervonic acid, which is one of the amino acids needed to maintain the normal of the human body, which has been proven to improve the activity of cranial nerves and is an important drug for the treatment of Alzheimer's disease, so it has important economic and pharmaceutical development value.
At present, most of the research work on garlic fruit in China focuses on the extraction, development and utilization of its oil, seedling breeding and cultivation, etc., and the research on population endangerment system, resource protection and sustainable utilization is still blank, and it is of great significance to study its population structure and dynamic characteristics for the protection and sustainable use of this tree species.
In this study, the concentrated and contiguous wild garlic fruit community was taken as the research object, and the research method combining sample method and field measurement method was adopted.
In this study, the population composition structure and number dynamics of the surviving plants in the natural community of garlic fruit in Funing County were studied, the static life table was compiled, the survival curve was drawn, and the time series prediction model was established to analyze the population dynamics.
The purpose of these studies was to analyze and explore the structural characteristics and dynamic changes of garlic population, predict its future development trend, and put forward corresponding protection measures.
In terms of tree species composition in the garlic fruit plots in the two areas, evergreen deciduous broad-leaved forests with evergreen tree species as the main body were shown.
The dominant tree species in the main tree layer in the garlic fruit community in the two regions were garlic fruit, Quercus japonica, Quercus mistletoe, Quercus variabilis, Acer triangular, S. superba, Alder, Ficus stripifolia, C. glauca, Sumac, and Quercus rubrum.
The shrub layer mainly includes arbor seedlings such as Phoebe runnanensis and S. superba, as well as bamboo, Rubus rose, firethorn, etc.; The herbaceous layer mainly includes kidney fern, golden powder fern, five-knotted miscanthus, iron mango and so on.
Diameter class structure and dynamic analysis of garlic population
The survey data showed that there was no significant difference in the diameter class structure of garlic fruit population in the two regions, and the average population density was 0.256 plants/m2.
The number of I. age class seedlings of garlic fruit populations in the two places was relatively small in the sample plot survey, while the number of small tree individuals was 71, accounting for 22.9% of the population. The number of large trees was 204, accounting for 65.81% of the population. The number of old trees was 35, accounting for 11.29% of the population.
This indicated that the number of small trees in the garlic fruit populations in the two regions was relatively sufficient, but the number of garlic fruits decreased sharply in both places after the fifth age class, and the number of individuals in the current age class was less than that in the next age class in the second and third age classes.
The results indicated that there was a fluctuation in the population size, and there may be a phenomenon of low conversion rate during the transition from seedlings and young trees to adult trees, while the population numbers of large trees in both regions decreased sharply during the transition period from large trees to old age.
The population of garlic fruit was mainly concentrated in the III.-V age class, and the sum of the proportions was as high as 76.77%, and there were fewer seedlings and small trees in the two regions, while the number of large trees was large, and the spindle-shaped structure of large trees and old trees decreased with the increase of age class, which was a stable population.
However, due to the unreasonable population allocation, the base of the diameter class structure is too narrow over time, and the adult trees gradually transform into old trees.
However, there is not a sufficient number of young trees to make up for the lack of adult trees, and if the population encounters strong environmental fluctuations, it is easy to cause large-scale population changes.
It can be seen from the dynamic change index of population age structure in the two areas of Funing County that the dynamic change index of individual population V1 in the I. age class in Banlun Township is significantly lower than that of the adjacent age class V2.
This indicates that the number of individuals in age class I has decreased and is less than that in age class II, but in terms of the overall number, the number of seedlings and young trees in the garlic fruit population in Banlun Township is still very sufficient.
The dynamic change index value of the number of individuals in the garlic fruit population in Zhesang Township continued to increase between the I. and IV. age classes, indicating that the number of seedlings and young trees in this population was increasing.
The dynamic change index of the number of individuals in the age structure of the population in the two regions decreased significantly between the IV. and V. age classes, indicating that the transition of seedlings and young trees to adult trees in the populations in the two regions was limited.
In general, the age structure dynamic change index of garlic fruit population in the two regions was positive and significantly greater than 0, indicating that the garlic population in the two regions was stable.
Survival function curve analysis of garlic population
The static life table and survival curve of the population were calculated from the specific time life table of the garlic fruit populations in the two regions, and it was shown that the standardized survival number lx of the garlic fruit populations in the two regions decreased with the increase of age.
The mortality and mortality rates of garlic fruit populations in Zhesang Township and Banlun Township peaked in the IV. age class, with mortality rates of 75.1% and 89.6%, and disappearance rates of Kx reaching 1.391 and 2.261, respectively.
This indicates that the population of garlic fruit in the two regions was disturbed during the transformation from young trees to adult trees, resulting in a low conversion rate.
The analysis of the survival curves of the two regions showed that the early mortality rate of garlic fruit populations in the two regions was high, and the standardized survival rate decreased with the increase of age class.
It was not until the IV. age that the mortality rate began to slow down and showed a gradual downward trend, indicating that the survival curve type in both places was Deevey-III. type.
According to the static life table of garlic fruit, the survival function S of garlic fruit population in the two regions showed a decreasing trend with the increase of age level, and the decline rate gradually slowed down after the IV. age level.
The changes of survival rate function S and cumulative mortality function F of garlic populations in the two regions were complementary, and the changes of death density function F and risk rate function λ curves of garlic populations in the two regions were almost the same.
This also indicates that the garlic fruit population in Banlun Township and Zhesang Township is scarce in the number of adult and old trees after IV., and the mortality rate increases slowly.
The number of individuals of each age class of garlic population was used as the original data, and the number of individuals of each age class after 2, 4, 6 and 8 age classes in the future was predicted by a translational shift method.
After two age classes, the number of garlic fruit individuals in the second age class increased from 40 to 49, while the number of garlic fruit individuals in Zhisang Township decreased from 82 to 78.
The results indicated that although the number of small trees in the two areas was large, the number of small trees in Banlun Township was declining, which may be caused by manual felling and the practice of clearing forest land for cultivated land.
After four age classes, the number of individuals in the two regions increased first and then decreased at age III.
Although the garlic fruit populations in the two regions are stable, there are cases of large-scale mortality during the transition of seedlings and small trees to adult trees.
The results of the quantitative analysis of population dynamics showed that with the growth of garlic plants, the age structure and diameter class structure of the garlic fruit population would gradually transform into a pyramid structure and become a growth population.
The scarcity of adult and old trees in the population reflects the difficulty of survival of older plants in the population, and the population growth is sensitive to environmental response, which is greatly affected by the interference of external factors, and the population gradually decreases with the increase of age class.
The population of Mudu Village, Banlun Township was distributed from small trees to large trees of different diameter classes or age classes, which was mainly related to the habitat of the distribution area, and the garlic fruit in the distribution area was mainly distributed in the relatively well-protected zoning reserve.
All garlic plants are registered and protected by local residents, so the vegetation damage in the distribution area is relatively small, and the adult or large trees can be preserved.
Due to the phenomenon of "one fruit in a thousand flowers" in garlic fruit, the seed setting rate is very low, and the population renewal is difficult, and simple in-situ conservation can only delay the decline trend of garlic population.
Therefore, we should carry out artificial seedling re-entry to forest to increase the number of individual populations, accelerate the process of population regeneration, and maintain the cultivation and sustainable use of garlic fruit plant ecosystem and its biodiversity resources.
Moreover, the huge economic value of garlic fruit should promote the combination of protection and efficient utilization, solve the technical difficulties of seedling breeding industrialization through related research on tissue cultivation seedlings, and develop and utilize plant resources on the basis of effective protection.