Mapping The Abundance Of Fagaceae Species In Subtropical And Tropical Forests In China

Spatial distributions of species abundance is one important research topic in ecology and biogeography.Fagaceae is an important component of subtropical and tropical forest ecosystems in China.Exploring the abundance pattern of this plant family provides new insights into better protecting and utilizing them sustainably.In this study,I selected the relative abundance data of Fagaceae from the recently compiled vegetation data in subtropical and tropical forests in China.First,the geographical distribution pattern of each genus was analyzed.Second,I constructed and compared the results of two species distribution models based on species presence-only data and relative abundance data,respectively.Finally,based on the abundance model of 58 species in Fagaceae,I mapped the relative abundance distribution patterns of different genera in subtropical and tropical regions and discussed the determinants of these patterns.The main results included:(1)In total,216 species were belonging to 6 genera of Fagaceae recorded in this database.The distribution centers of plant richness were in the subtropical western and eastern regions,mainly in Yunnan and Guangxi provinces.Species richness of Fagaceae decreased as latitude increased,accompanied by the decreasing of evergreen species and the increasing of deciduous species.The spatial distribution of each genus is distinct,with Trigonobalanus mainly distributed in the southern Yunnan;Fagus and Castanea mainly distributed in the subtropical central and northern regions;Castanopsis and Lithocarpus mainly distributed in the subtropical central and southern regions;Quercus distributed widely in the study area.(2)The results of species distribution model based on presence-only data and relative abundance data showed that different environmental factors determined the occurrence and abundance distribution of plants in Fagaceae.The precipitation of driest month was the main environmental factor that determined its occurrence,while annual mean temperature and diurnal mean range were the main factors for the species relative abundance,the topographic factors(e.g.,elevation variation)is the second.The relative abundance of different species is affected by different environmental factors.One the other hand,although the probability of species occurrence was significantly related to the relative abundance of species,the effect was weak.The overlap rate between the regions of high-probability distribution and those of high relative abundance distribution was very low,indicating that the occurrence data cannot be used as the proxy of the relative abundance.(3)Combined with climatic and topographic factors,the relative abundance distributions of 58 common species in Fagaceae were predicted.The prediction ability of the species with narrow distributions was higher than that with wide distributions.The coefficients of determination(R~2)of the models of all 58 species ranged from 0 to0.923,with an average of 0.127.Among them,7 species(12%)had R~2greater than0.3,and the model had the best prediction ability for Lithocarpus naiadarum(0.364-0.923,mean R~2=0.64).Only 50%of the species showed that the relative abundance were related to environmental factors,these results indicated that the factors determined the relative abundance distribution of Fagaceae were very complex,climate and topography were only a part.(4)The relative abundance distribution patterns of different genera are different.Consistent with its life history,Castanea was centered in the subtropical northern regions and mainly affected by the precipitation of driest month;Fagus was mainly distributed in subtropical northern and southern alpine regions;Lithocarpus was distributed widely distributed in south and middle subtropical regions,and only a few species were dominant;The geographical distribution of Castanopsis was significantly different,and different regions were affected by different environmental factors,forming two high-abundance distribution areas within Yunnan and the middle east subtropical zones;Quercus was widely distributed in China,and the high relative abundance areas mainly occurred in the central,northern and western subtropical regions.In summary,species abundance data is more reliable than the presence-only data in reflecting species'distributions,showing the regions with high-probability distribution based on presence-only data cannot be used to represent the regions with high-abundance distribution.The distributional regions of relative abundance vary greatly among species due to the different environmental determinants.This study provides a scientific basis for further studies on the spatial patterns of relative abundance,the protection,and sustainable uses of Fagaceae plants.