Subjects: Biology >> Botany >> Applied botany submitted time 2022-07-05 Cooperative journals: 《广西植物》
Abstract： The spatial distribution pattern of population is an important means to describe population characteristics, interspecific interactions, and its relationship between population and environment. Cyclobalanopsis glauca is a constructive population of climax community in karst ecosystems, in order to further understand the spatial distribution pattern of its populations. According to the sample plot investigation specification, a sample plot of 60 m × 60 m was set up, and the woody plants in the plot were spatially located and investigated for each tree. The C. glauca population was divided into three different diameter classes in the study, belonging to saplings (DBH<2 cm), small trees (2 cm≤DBH<10 cm), adult trees (10 cm≤DBH). Using the point pattern analysis method, g (r) and L12 (r) functions based on Ripley’sK function was used for the analysis of the spatial distribution pattern and correlation analysis of C. glauca population in different diameter classes. The results were as follows: (1)The diameter class structure of C. glauca population is in an inverted “J” distribution. (2) On the small scale, the stage of saplings, small trees and adult trees, the spatial distribution pattern tends to cluster distribution，and the small trees, large tree stage tends to random distribution on the large scale. (3) The performance of spatial correlation between different diameter classees is different, the seedling and sapling are positively related on the scale of 0-15 m; sapling and adult trees reflected in the scale of 0-10 m is no correlation, it showed a positive correlation on the scale of 10-15 m; Seedling and adult trees performance on the scale of 0-2 m is no correlation, it showed positive correlation on the scale of 2-15 m. The spatial distribution pattern and correlation of C. glauca population in the karst area of Guilin change with the spatial scale and development stage, which was the result of the combined effects of the population’s bioecological characteristics, intraspecific and interspecific relationships, and environmental conditions. The results of the study can provide basic information for the formation and maintenance mechanism of plant community and resource utilization research of karst hills.
Subjects: Biology >> Botany >> Applied botany submitted time 2022-05-21 Cooperative journals: 《广西植物》
Abstract： Cenchrus spinifex is one of the invasive plant species in China, which seriously affects the animal husbandry of pastures and pastures in China. Therefore, the response of suitable distribution of C. spinifex to climate change under future climate change scenarios will provide important management basis and control measures for the prevention of invasive plants in China. Therefore, based on the MaxEnt model, this study used 103 geographical distribution data of C. spinifex and 19 climatic and environmental factors to analyze and predict the suitable distribution area of C. spinifex in China under two climate change scenarios of RCP 2.6 and RCP 8.5 in the 2050s and 2070s. The results showed that: (1) The current suitable distribution area of C. spinifex occupies 4.00% of the study area, which was mainly distributed in Northeast China borderline by Inner Mongolia, Jilin and Liaoning. (2) Under the two future climate change scenarios, the suitable distribution areas for each grade of C. spinifex will expand to a certain extent compared with the current one. Hereinto, the medium climatically suitable areas might increase by 38.26%. (3) Annual mean temperature, standard deviation of seasonal temperature variation, and precipitation in the wettest season are the main climatic factors affecting the distribution of C. spinifex. (4) In the future, the distribution centroid of C. spinifex will generally move westward. The above results indicate that the currently invaded areas of C. spinifex in China are far smaller than the potentially invaded areas, and it may further spread to the arid and semi-arid regions of my country. In order to prevent the harm caused by the widespread spread of C. spinifex in northern my country, we need to focus on its preventive measures and invasion situation in the future.
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