Ecological Evolution And Biodiversity Database Of The Global Smilacaceae

The global distribution of species richness is far from uniform.There are differences in species diversity among different regions,that is,the heterogeneity of the of species diversity.The mechanisms underlying this pattern remain one of the most debated issues in ecology and biogeography.Although a large number of studies have been conducted on the species diversity pattern related to latitude and elevation,few studies have focused on the causes of inter-continental species diversity heterogeneity.Smilacaceae(Liliales),a woody monocot lineage,provides an ideal model to test how environmental factors interact with speciation and extinction(i.e.net diversification),and form diversity heterogeneity across regions at global scale.This study combined macroecological and macroevolutionary biology methods to reconstruct the Smilacaceae phylogeny and explore the formation history and evolution mechanism of species diversity heterogeneity from aspects of speciation,extinction,and dispersal among continents in Smilacaceae.In addition,we constructed biodiversity database of Smilacaceae through biodiversity informatics.The main conclusions were as follows:1.Global patterns of Smilacaceae diversityBased on 19,831 geographical distribution of 223 species in Smilacaceae,we used Maxent(maximum entropy model)to obtain 223 potential distribution and draw highresolution diversity heat map.More than 91% of species in Smilacaceae were found in three diversification centers: tropical-subtropical Asia(131 species,58.74%,maximum species number per grid,MSPG = 30),subtropical North America including Central America(43 species,19.3%,MSPG = 16)and tropical South America(44 species,19.8%,MSPG = 22).2.Intercontinental niche differentiation of SmilacaceaeNiche analysis based on six environmental variables,i.e.BIO1,BIO2,BIO12,BIO15,BIO18 and altitude,revealed the niche differences of Smilacaceae in different continents.The first,second,and third axes of OMI ordination explained 35.5%,29.3% and 13.1% of the total variance in species niche position,respectively.The high loading of first,second and third axis were BIO1(Annual Mean Temperature,54.3%),BIO18(Precipitation of the Warmest Quarter,62.8%)and BIO2(Mean Diurnal Range,53.3%).The multivariate dispersions(F = 18.468,p < 0.001,d.f.= 222)and niche widths analysis(clade-level niche widths of NW clade = 0.102,clade-level niche widths of NW clade = 0.046)further indicated that there were significant levels of divergence between OW and NW clade.3.Temporal and spatial framework of the evolutionary history of SmilacaceaeThe temporal and spatial framework of evolution history of Smilacaceae was constructed based on 8 gene fragments from 135 taxa and combined with biogeographic methods.The ancestral group of Smilacaceae originated in the high latitudes of the Laurasia continent from the late cretaceous(67.86 Ma)to the late Eocene(35.46 Ma).The OW and NW clade of Smilacaceae diverged in the early Oligocene(32.64 Ma)and retreated to low latitudes,evolving independently(OW: 28.62 Ma;NW: 27.21 Ma).The reconstruction of ancestral distribution shows that the OW and NW clade of Smilacaceae occurred frequent multi-directional dispersal events and shifted multiple times from their temperate ancestral biome into the tropics,exhibiting a ‘into-thetropics' pattern.4.The drivers of global patterns in Smilacaceae diversityCombined ecological and evolutionary biology methods to analyze the drivers of global patterns in Smilacaceae diversity from aspects of speciation,extinction and dispersal.In the whole evolutionary history,the net diversity rate of Smilacaceae increased steadily from 0.107 sp/Myr to 0.163 sp/Myr during 35 Ma to 5Ma.Before late Miocene(10 Ma),the net diversity rate of NW clade(average growth rate = 0.0011)and OW clade(average growth rate = 0.0014)were similar.However,during the period of 9.3–6.8 Ma,the net diversification rate of OW clade increased sharply(average growth = 0.0101),while the net diversification rate of NW clade only showed stable and gradual growth(average growth rate = 0.0010).The strong positive correlation(Intercept = 0.11,T = 17.75,P < 2.312E-16)between net diversification rate and rate of niche divergence(PGLS residuals between clade-level niche widths and mean species niche widths)further indicated that the heterogeneity of species diversity rate caused by niche diversity may be the main driving factor for global pattern of Smilacaceae diversity.5.Construction of biodiversity database in SmilacaceaeBased on biodiversity informatics,we integrated the information of species diversity,genetic diversity and ecosystem diversity to build biodiversity database of Smilacaceae.In this study,biodiversity data such as species information(223 species),species collection information(2,385 collection photos),species distribution information(19,831 sites),species specimen information(12,109 specimen photos),phylogenetic information(876 genes)and literature(61 floras and 168 related research papers)of Smilacaceae were collected.Combined with analysis results of macroecology and macroevolutionary biology,the biodiversity database of Smilacaceae based on My SQL was constructed,realizing function of resource query,retrieval and update of biodiversity data.