Phylogenetic Analysis Of North-South Flora Converge Distribution In Shandong

Floristic research has played an important role in natural planning,species protection,resource utilization,and ecological construction.The research of flora in China has a long history of over a hundred years and is still in the ascendant.However,these early studies have more or less subjective or artificial errors,and there are shortcomings that cannot be repeated.We use the Operational Taxonomic Unit(OTU),which is most commonly used in specific plant species substitution systematics and genetic research,as the main method of floristic research,using cluster analysis instead of subjective faunal division,and combining big data analysis methods to analyze multi-faunal relationships by exploring the similarity of various taxonomic levels,To explore the deep connotation of the flora in an objective and quantitative manner.In response to the phenomenon of plant compatibility in northern and southern Shandong discovered in previous surveys,a database of 2410 species of seed plants in 6 classes,48 orders,161 families,865 genera,was established from the perspective of flora in Shandong and its surrounding ten provinces(or municipalities).Cluster analysis and numerical classification methods were used to explore the geographical pattern of plants in the region,and the differences in the distribution of species from the north to the south were analyzed.The results show that there is a certain degree of "north south plant convergence phenomenon" in Shandong Province,specifically manifested as follows:1.The unique environmental conditions in Shandong have nurtured special coastal vegetation types.There are a total of 174 species of characteristic plants in 39 families,114 genera,including 10 representative coastal plants,14 medicinal plants,and 3 national key protected or endangered species.2.Shandong belongs to the warm temperate deciduous broad-leaved forest region,which has similarities with the flora of northern and southern regions.3.The composition of monocotyledonous and dicotyledonous plants in Shandong lies between the northern and southern regions,and is closer to the northern region.4.The species composition of Shandong at the order level is more similar to the flora of southern China.5.Each family and genus presents a relatively obvious north-south distribution trend bounded by Shandong.Violaceae,Geraniaceae,Malus,Pyrus,and Cynanchum are only widely distributed in Shandong and the northern region,while Euphorbiaceae,Amaranthaceae,Ulmaceae,Euphorbia and Euonymus are only widely distributed in Shandong and southern regions.6.We have discovered many newly distributed species in Shandong,such as Zehneria japonica,Centrothera cochinchinensis and Adonis ramosa,which have characteristics of northern and southern flora.7.Shandong is roughly located in the transitional region between the north and south in terms of plant evolutionary morphology and other life forms,with species distribution in plant evolutionary morphology,Lignification and life span in Shandong closer to the southern region.We also combine climate factor data and geological data to analyze from the perspectives of climate and geological factors.The results show that the climate of the south and the north has formed an obvious boundary in Shandong.There is an obvious north-south convergence phenomenon in four climate factors of Shandong Province,namely,the average daily temperature range,seasonal temperature,annual temperature range and seasonal precipitation.This phenomenon explains the reasons for the convergence of flora in Shandong from the perspective of climate;According to the research,the geological cause of the convergence of flora in Shandong Province may be 1.The surviving plants in the shelter of Shandong Province during the ice age diffused in the Holocene to form a pattern of plant convergence 2.The Holocene transgression led to the large-scale proliferation of plants in the north and south and then evolved into the existing convergence pattern.This research is an attempt to analyze the big data of specific species and richness in the research of flora,which can provide reference for biogeography research in other regions.Compared with the traditional flora research method,it has the advantage of repeatability and avoids human error to a large extent.In this research,the species and flora of Shandong Province and its surrounding areas were analyzed for the first time by using big data statistics and quantitative analysis methods.It was found that Shandong Province met the objective conditions for the settlement and growth of northern and southern plants in terms of climate,geography and environmental factors,and there was a convergence of northern and southern flora at various classification levels and life type levels;This discovery provides new ideas for ecological planning,species protection,ecological construction,and scientific development in Shandong Province,and provides guidance plans for species transplantation and expansion work such as "North Medicine South Propagation " and "South Tea North Introduction".