Topography and structural diversity regulate ecosystem multifunctionality in a subtropical evergreen broad-leaved forest

Forest functionality is generally considered a byproduct of forest diversity. Perhaps unsurprisingly, many researchers associate increasing multi-functionality with increasing diversity. Diversity, however, is an often-overused word that may describe a host of features, including the diversity of species, functional trait and structure. Furthermore, variable environmental features (such as topography) influence the interaction between forest plants and their function. Incorporating complex topography (like that associated with tropical and subtropical forests) into estimates of forest functionality is challenging and highly uncertain. In this paper, we applied structural equation models to disentangle the relative importance of topography and different components of what might be considered “plant diversity” to forest multifunctionality using repeated census of a 20-ha subtropical forest plot. We found that multifunctionality was principally influenced by structural diversity more so than either species composition or functional trait diversity. In our SEM model approach, we observed variations in topography could account for about 30% of variation in multifunctionality. Furthermore, variations in topography could indirectly influence forest multifunctionality by changing species composition, functional trait diversity, and structural diversity. Our work highlights the importance of topography and forest structure in regulating subtropical forest multifunctionality on the local scale. This suggests future subtropical forest management should focus on regulating forest structure. Namely, our results suggest land managers must take topography (and the complex interaction between topography and plant diversity) into account in order to build robust and multifunctional forests

Direct and indirect effects of climate on richness drive the latitudinal diversity gradient in forest trees

Data accessibility statement: Full census data are available upon reasonable request from the ForestGEO data portal, http://ctfs.si.edu/datarequest/ We thank Margie Mayfield, three anonymous reviewers and Jacob Weiner for constructive comments on the manuscript. This study was financially supported by the National Key R&D Program of China (2017YFC0506100), the National Natural Science Foundation of China (31622014 and 31570426), and the Fundamental Research Funds for the Central Universities (17lgzd24) to CC. XW was supported by the Strategic Priority Research Program of the Chinese Academy of Sciences (XDB3103). DS was supported by the Czech Science Foundation (grant no. 16-26369S). Yves Rosseel provided us valuable suggestions on using the lavaan package conducting SEM analyses. Funding and citation information for each forest plot is available in the Supplementary Information Text 1.Peer reviewedPostprin

Quantifying spatial phylogenetic structures of fully stem-mapped plant communities

Analysis of the phylogenetic similarity of co-occurring species at different spatial scales is increasingly used for decoding community assembly rules. Here, we integrated the analysis of phylobetadiversity and marked point pattern analysis to yield a new metric, the phylogenetic mark correlation function, k(d)(r), to quantify spatial phylogenetic structure of fully stem-mapped communities.k(d)(r) is defined as the expected phylogenetic distance of two heterospecifics separated by spatial distance r, and normalized with the expected phylogenetic distance of two heterospecifics taken randomly from a study area. It measures spatial phylogenetic turnover relative to spatial species turnover and is closely related with the spatially explicit Simpson index. We used simulated fully stem-mapped plant communities with known spatial phylogenetic structures to assess type I and II errors of the phylogenetic mark correlation function k(d)(r) under a null model of random phylogenetic spatial structure, and to test the ability of the k(d)(r) to detect scale-dependent signals of phylogenetic spatial structure. We also compared the performance of the k(d)(r) with two existing measures of phylobetadiversity that have been previously used to analyse fully stem-mapped plots. Finally, we explored the spatial phylogenetic structure of a 24-ha fully stem-mapped subtropical forest in China. Simulation tests showed that the new metric yielded correct type I and type II errors and accurately detected the spatial scales at which various processes (e.g. habitat filtering and competition) were invoked to generate spatial phylogenetic structures. The power of the k(d)(r) was not affected by a phylogenetic signal in species abundance and different topologies of the phylogenetic tree. Replacing phylogenetic distance by functional distance allows for application of the k(d)(r) to estimate spatial correlations in functional community structure. Thus, the k(d)(r) allows trait and phylogenetic structure to be analysed in the same framework. The phylogenetic mark correlation function is a powerful and accurate tool for revealing scale-dependent phylogenetic/functional footprints in community assemblages and allows ecologists to keep up with the increasingly available data of fully stem-mapped plots, functional traits and community phylogenies

Evaluation of faciocutaneous clues to systemic diseases: A learning module for Chinese undergraduate medical students

Background: Medical students will encounter cutaneous lesions associated with systemic disorders during their training and career. However, there are no chapters in Chinese undergraduate medical textbooks regarding these lesions. Objective: The objective of the present study was to evaluate the impact of an additional learning module about cutaneous lesions associated with systemic disorders for Chinese undergraduates. Methods: In this medical course, we introduced a case-based clinical learning module. This module was evaluated with a pre-/postcourse questionnaire and a final multichoice examination. Results: After learning, more students agreed that some skin lesions could serve as “windows” to hidden systemic diseases, and it was more important to learn how to distinguish lesions associated with systemic diseases from simplex ones. We found that the group that was provided conventional teaching plus this module scored significantly better (52.75 ± 23.96) than the conventional teaching group (40.53 ± 21.43; t = 2.370, p = 0.020) in the final multichoice examination. Conclusion: Introducing this additional learning module may offer an early opportunity to explore systemic diseases from a dermatological view and is likely to lay the foundations for interdisciplinary collaboration in the future practice for medical students

Relationship between Polymorphism of Nicotinic Acetylcholine Receptor Gene CHRNA3 and Susceptibility of Lung Cancer

Objective: To investigate the relationship between polymorphism of nicotinic acetylcholine receptor gene CHRNA3 and susceptibility of lung cancer. Methods: Sixty hundred patients with lung cancer and 600 healthy people were respectively selected. TaqMan-MGB probe technique was applied to detect rs3743073 (T > G) genotypes at SNPs site on CHRNA3. The difference of genotype distribution among groups was compared, and its relationship with lung cancer was also investigated. Results: There was statistical significance regarding the distributions of CHRNA3 rs3743073 (T> G) genotype and allele frequencies in patients with lung cancer and healthy people (P < 0.05). By comparison to the patients with TT genotype, the risk of developing lung cancer in patients with TG and GG genotypes was increased 1.68 times (95%CI ＝ 1.30 － 2.19, P < 0.05) and 1.30 times (95%CI ＝ 1.05 － 1.61, P < 0.05), respectively, while the risk of developing lung cancer in patients with rs3743073G (TG and GG) was increased 0.65 times (95%CI ＝ 0.50 － 0.84, P < 0.05) . Further analysis demonstrated that of the patients more than 60 years old, male and smoking, the risk of developing lung cancer in those with rs3743073G mutant genotypes was elevated significantly (P < 0.05). Conclusion: The risk of developing lung cancer in patients with rs3743073G mutant genotypes of CHRNA3 gene is increased markedly, especially in those more than 60 years old, males and smoking ones

Abnormally increased low-density granulocytes in peripheral blood mononuclear cells are associated with interstitial lung disease in dermatomyositis

<p><i>Objective</i>: We previously found that neutrophil extracellular traps (NETs) were associated with interstitial lung disease (ILD) in dermatomyositis (DM) patients. However, it is unclear whether low-density granulocytes (LDGs), endowed with enhanced NET formation capabilities, contribute to the pathogenesis of ILD. This study aims to elucidate the relationship between LDGs and DM-associated ILD.</p> <p><i>Methods</i>: We recruited 48 DM patients (28 with ILD) as well as 19 healthy volunteers for this study. The percentage of LDGs in peripheral blood mononuclear cells (PBMCs) was ascertained by flow cytometry. Plasma cfDNA was measured by using the Quant-iT PicoGreen dsDNA Kit and plasma LL-37 was tested by using the LL-37 ELISA kit.</p> <p><i>Results:</i> The percentage of LDGs was 7.1 times higher in DM patients than in healthy controls. LDG percentage was 2.7 times higher in DM patients with ILD than in DM patients without ILD. Additionally, LDG percentage positively correlated with MYOACT lung disease activity scores, and NET/neutrophil-related marker levels (LL-37, cfDNA, MPO, and MMP-8) in the DM group were significantly higher than those in the control group.</p> <p><i>Conclusion</i>: The abnormal increase of LDGs may exacerbate abnormal NET regulation and further contribute to the pathogenesis of ILD in DM patients by abnormally forming NETs.</p

Differences in Density Dependence among Tree Mycorrhizal Types Affect Tree Species Diversity and Relative Growth Rates

Conspecific negative density dependence (CNDD) may vary by tree mycorrhizal type. However, whether arbuscular mycorrhizal (AM)-associated tree species suffer from stronger CNDD than ectomycorrhizal (EcM) and ericoid mycorrhizal (ErM)-associated tree species at different tree life stages, and whether EcM tree species can promote AM and ErM saplings and adults growth, remain to be studied. Based on the subtropical evergreen broad-leaved forest data in eastern China, the generalized linear mixed-effects model was used to analyze the effects of the conspecific density and heterospecific density grouped by symbiont mycorrhizal type on different tree life stages of different tree mycorrhizal types. The results showed that compared to other tree mycorrhizal types at the same growth stage, EcM saplings and AM adults experienced stronger CNDD. Heterospecific EcM density had a stronger positive effect on AM and ErM individuals. Species diversity and average relative growth rate (RGR) first increased and then decreased with increasing basal area (BA) ratios of EcM to AM tree species. These results suggested that the stronger CNDD of EcM saplings and AM adults favored local species diversity over other tree mycorrhizal types. The EcM tree species better facilitated the growth of AM and ErM tree species in the neighborhood, increasing the forest carbon sink rate. Interestingly, species diversity and average RGR decreased when EcM or AM tree species predominated. Therefore, our study highlights that manipulating the BA ratio of EcM to AM tree species will play a nonnegligible role in maintaining biodiversity and increasing forest carbon sink rates