Unveiling the complex networks of urban tree diversity research: A global perspective.

Ecosystem services offered by urban forests must be proactively managed to remain diverse and sustainable. Recent research findings deserve a systematic synthesis to elucidate inherent knowledge structures and dynamics. This study focused on the urban tree diversity theme from 2000 to 2022. Web of Science Core Collection database provided bibliometric details on academic publications. The data-driven quantitative analysis explored research quantities, emphasis, trends, patterns, linkages, and impacts by countries, institutions, authors, journals, and citations. Publications and research topics have expanded continually, with accelerated growth in recent years. Research activities, outputs and interactions demonstrated conspicuous spatial clustering. A few countries, institutions and researchers generated a notable proportion of publications. Their scholarly contributions were visualized in knowledge graphs as complex networks of nodes and inter-node links. Keyword analysis generated a network to indicate research hotspots and frontiers to steer and prioritize future studies. Recent findings affirmed that cities can harbor substantial tree diversity due to enhanced habitat heterogeneity and successful species adaptation. Aligning tree traits with environmental conditions and management objectives can improve benefits. Urbanization can filter tree traits to shape community assemblages through stressors: habitat degradation, fragmentation and loss, in conjunction with pollution, climate change, and introduced species. Diversity preservation strategies include protecting remnant natural vegetation, connecting green spaces, and restoring complex canopy geometry and biomass structure. The emerging frontiers are marked by modeling future species distributions, leveraging technologies like remote sensing, linking ecology with human values, and committing to community-based stewardship. Management can be upgraded by interdisciplinary perspectives integrating ecological science and social engagement. The findings highlight the need for biodiversity enrichment anchored by native species, trait-matched assemblages, adaptive policies, and community participation to create livable-green cities. This review synthesizes key advances in urban tree ecology and biodiversity research to inform the planning and stewardship of resilient urban forests.

Response of Plant and Soil N, P, and N:P Stoichiometry to N Addition in China: A Meta-Analysis.

Nitrogen (N) and phosphorus (P) are key elements essential for plant growth and development. Due to fertilizer application, rapid urbanization, and fossil fuel combustion, nitrogen deposition has reached relatively high levels in China. However, there is still uncertainty regarding the response of N:P stoichiometry in plants and soil to N deposition across different ecosystems. Therefore, a meta-analysis was conducted using 845 observations from 75 studies to evaluate the response of plant and soil N and P concentrations and N to P ratios across various ecosystems to N addition. The analysis revealed that N concentration and N:P stoichiometry in plants and soil increased under N addition, while P concentration in plants and soil decreased on average. Furthermore, the magnitude of these responses was related to the N input rate and experimental duration. Finally, the effects of N addition on N concentration, P concentration, and N:P in terrestrial ecosystems would alter their allocation patterns, depending on relevant climate factors such as mean annual temperature and mean annual precipitation. This study highlights the ecological impact of N addition on the biogeochemical cycling of major elements (N and P) in terrestrial ecosystems in China. These findings are necessary for improving our understanding of the characteristics of plant ecological stoichiometry and helping to plan measures for increasing N deposition.

Scale-dependent effects of species diversity on aboveground biomass and productivity in a subtropical broadleaved forest on Mt. Huangshan.

The relationship between species diversity and biomass/productivity is a major scientific question in ecology. Exploring this relationship is essential to understanding the mechanisms underpinning the maintenance of biodiversity. Positive, negative, and neutral relationships have been identified in controlled experiments and observational research. However, increasing evidence suggests that the effects of species diversity on aboveground biomass and productivity are influenced by biotic and abiotic factors, but it remains unclear whether scale-dependent effects affect aboveground biomass and productivity. Herein, we used a generalized linear regression model and a structural equation model to explore relationships between species diversity and productivity/aboveground biomass under different scales and to investigate the effects of topographical factors and species diversity on ecosystem functioning. The results revealed a positive relationship between biodiversity and ecosystem functioning based on species diversity and aboveground biomass. Different sampling scales may impact the relationship between species diversity and ecosystem functioning. A positive relationship was found between species richness and productivity at medium and large scales; however, ambiguous relationships were found in productivity and other species diversity indices. Elevation was a key factor affecting both biomass and productivity. These results suggest that species diversity is not the only factor affecting biomass and productivity, and the positive correlation between species diversity and ecosystem functioning is mediated by abiotic factors.

The complete chloroplast genome sequence of Quercus sessilifolia Blume (Fagaceae).

Quercus sessilifolia Blume is one of the dominant tree species in East Asian evergreen broadleaved forests. In this study, we assembled and characterized the plastome of Q. sessilifolia using Illumina paired-end data. The circular genome is 160,813 bp in size, consisting of two copies of inverted repeat (IR) regions of 25,862 bp, one large single-copy (LSC) region of 90,218 bp, and one small single-copy (SSC) region of 18,871 bp. It encodes a total of 113 unique genes, including 79 protein-coding genes, 30 tRNA genes, and four rRNA genes. Phylogenetic analysis based on 28 chloroplast genome sequences indicated that Q. sessilifolia was most closely related to Q. myrsinifolia with 90% bootstrap support.

The complete chloroplast genomes of three Hamamelidaceae species: Comparative and phylogenetic analyses.

Hamamelidaceae is an important group that represents the origin and early evolution of angiosperms. Its plants have many uses, such as timber, medical, spice, and ornamental uses. In this study, the complete chloroplast genomes of Loropetalum chinense (R. Br.) Oliver, Corylopsis glandulifera Hemsl., and Corylopsis velutina Hand.-Mazz. were sequenced using the Illumina NovaSeq 6000 platform. The sizes of the three chloroplast genomes were 159,402 bp (C. glandulifera), 159,414 bp (C. velutina), and 159,444 bp (L. chinense), respectively. These chloroplast genomes contained typical quadripartite structures with a pair of inverted repeat (IR) regions (26,283, 26,283, and 26,257 bp), a large single-copy (LSC) region (88,134, 88,146, and 88,160 bp), and a small single-copy (SSC) region (18,702, 18,702, and 18,770 bp). The chloroplast genomes encoded 132-133 genes, including 85-87 protein-coding genes, 37-38 tRNA genes, and 8 rRNA genes. The coding regions were composed of 26,797, 26,574, and 26,415 codons, respectively, most of which ended in A/U. A total of 37-43 long repeats and 175-178 simple sequence repeats (SSRs) were identified, and the SSRs contained a higher number of A + T than G + C bases. The genome comparison showed that the IR regions were more conserved than the LSC or SSC regions, while the noncoding regions contained higher variability than the gene coding regions. Phylogenetic analyses revealed that species in the same genus tended to cluster together. Chunia Hung T. Chang, Mytilaria Lecomte, and Disanthus Maxim. may have diverged early and Corylopsis Siebold & Zucc. was closely related to Loropetalum R. Br. This study provides valuable information for further species identification, evolution, and phylogenetic studies of Hamamelidaceae plants.

Complete mitochondrial genome of Parnassius glacialis (Lepidoptera: Papilionidae).

Parnassius glacialis is a butterfly species distributed in China, Korea, Japan. The complete P. glacialis mitochondrial genome was assembled using Illumina sequencing data. The mitogenome is 15,353 bp long and contains 13 protein-coding genes, 22 transfer RNA genes, and 2 ribosomal RNA genes. A phylogenetic analysis of P. glacialis and 14 related Papilionidae species indicated that P. glacialis is clustered with other Parnassius species. This study generated useful genetic information for future studies on the taxonomy, phylogeny, and evolution of Papilionidae species.

Selaginellawuyishanensis (sect. Tetragonostachyae, Selaginellaceae), a new species from East China and its phylogenetic position based on molecular data.

A new spikemoss species, Selaginellawuyishanensis, is described and illustrated based on materials collected from Fujian Province, East China. The new species can be distinguished from S.lutchuensis Koidzumi and S.albociliata P. S. Wang by its leaves with extremely long cilia (up to 8 mm) and distinctly white margins, ovate ventral sporophylls, and sporophyll-pteryx completely inverted on dorsal sporophylls. In the present work, a molecular phylogeny, taxonomic description, distribution information, line drawing, and photographs of this new species are presented. A morphological comparison is also given to distinguish it from morphologically similar species in Selaginellasect.Tetragonostachyae (Hook. & Grev.) Hieron. & Sadeb.

The complete chloroplast genome sequence of Corylopsis multiflora Hance var. nivea Chang.

Corylopsis multiflora Hance var. nivea Chang is a variety of the species C. multiflora in the family Hamamelidaceae and is classed as critically endangered (CR) in the Red List of China Higher Plants. The complete chloroplast genome sequence of this taxon (as C. multiflora var. nivea in GeneBank, accession number: MW043717) was reported in this study. The genome size is 158,993 bp in length, consisting of a pair of inverted repeat regions (IR, 26,213bp), large single copy (LSC, 87,895bp) and small single copy (SSC, 18,672bp). A total of 133 genes were annotated that included 87 protein coding genes (PCGs), 37 transfer RNA (tRNAs), and 8 ribosome RNA (rRNAs) and 1 pseudo gene. GC content were 38.01%. The Bayesian phylogeny tree showed that C. multiflora var. nivea formed a monophyletic branch with Corylopis coreana and Corylopsis spicata.

A Meta-Analysis Indicates Positive Correlation between Genetic Diversity and Species Diversity.

Species diversity (SD) and genetic diversity (GD) are the two basic levels of biodiversity. In general, according to the consensus view, the parallel effects of environmental heterogeneity, area, and connectivity on two levels, can drive a positive correlation between GD and SD. Conversely, a negative correlation or no correlation would be expected if these effects are not parallel. Our understanding of the relationships between SD and GD among different ecosystems, sampling methods, species, and under climate change remains incomplete. In the present study, we conducted a hierarchical meta-analysis based on 295 observations from 39 studies and found a positive correlation between genetic diversity and species diversity (95% confidence interval, 7.6-22.64%). However, significant relationships were not found in some ecosystems when we conducted species-genetic diversity correlation analysis based on a single ecosystem. Moreover, the magnitudes of the correlations generally decreased with the number of sampling units and the annual average the temperature of sampling units. Our results highlight the positive correlation between GD and SD, thereby indicating that protecting SD involves protecting GD in conservation practice. Furthermore, our results also suggest that global increases in temperature during the 21st century will have significant impacts on global biodiversity.

Mismatch Between Specific and Genetic Diversity in an Evergreen Broadleaf Forest in Southeast China: A Study Case of 10.24 ha Forest Dynamics Plot of Huangshan.

For a long time, forestry management has often focused on the protection of species diversity, and mistakenly believed that protecting species diversity protects genetic diversity. Therefore, research that integrates community ecology and population genetics has become important because it can help elucidate whether the targets for protecting specific and genetic diversity are congruent. In this study, we have emphasized the impact of the community on the population because no previous studies have considered the community composition of a place a priori. Based on the Huangshan 10.24 ha dynamics forest plot, we a priori considered the community composition in the plot to test species-genetic diversity among the tree layers. Firstly, a redundancy analysis (RDA) found that Castanopsis eyrei and Pinus massoniana were the dominant species. Secondly, specific and genetic diversity are not congruent in Huang Shan. Finally, the structural equation model (SEM) showed that the different degrees of response by community composition and population structure to environmental heterogeneity are the main reasons for the mismatch between species diversity and genetic diversity. The results suggest that we must focus on genetic diversity, as well as on protecting species diversity.

The complete chloroplast genome of Distylium tsiangii Chun ex Walker, a rare and endangered plant.

Distylium tsiangii Chun ex Walker is an evergreen tree species endemic to China. It has been classified as critically endangered in the Red List of China Higher Plants. Here, we sequenced, assembled, and analyzed the complete chloroplast (cp) genome of D. tsiangii. The plastome is 159,125 bp in length, with a typical quadripartite structure and consisting of a pair of inverted repeat (IR) regions (26,220 bp) separated by a large single copy (LSC) region (87,897 bp) and a small single copy (SSC) region (18,788 bp). The overall GC content was 38.00%. A total of 131 genes were annotated, including 37 tRNA genes, 86 protein-coding genes, and eight rRNA genes. Phylogenetic analysis showed that D. tsiangii was more closely related to Parrotia subaequalis.

The complete chloroplast genome sequence of Distylium macrophyllum (Hamamelidaceae).

Distylium macrophyllum H.T.Chang is a critically endangered tree species endemic to southern China. In this study, we assembled and characterized the plastome of D. macrophyllum using Illumina paired-end data. The circular genome is 159,089 bp in size, consisting of two copies of inverted repeat (IR) regions of 26,235 bp, one large single-copy (LSC) region of 87,822 bp, and one small single-copy (SSC) region of 18,797 bp. It encodes a total of 114 unique genes, including 80 protein-coding genes, 30 tRNA genes, and four rRNA genes. Phylogenetic analysis based on 13 cp genome sequences indicated that D. macrophyllum was sister to the clade of D. tsiangii and Parrotia subaequalis.