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Plants and soil bacteria exert a vital function in mediating soil ecosystem multifunctionality (EMF). Nevertheless, plant and soil bacteria interaction during forest secondary succession is poorly understood, and their roles in soil EMF remain largely unexplored. The dynamics of soil physicochemical properties and bacterial diversity was studied in southwest China during forest succession from coniferous to monsoon broadleaf evergreen. Interdomain ecological networks (IDEN) were adopted for investigating plant–bacteria associations. With the purpose of assessing how soil factors, bacterial community and plant diversity influenced soil EMF, the structural equation model (SEM) was used. It was discovered that both soil bacterial diversity and soil EMF gradually increased with the succession. IDEN analysis revealed that plant–bacteria ecological networks differed significantly across successional stages. Keystone plant species richness (KSR) increased with succession, which benefited soil bacteria diversity (path coefficient = 0.802, p < 0.001) while having a direct negative impact on pH (path coefficient = −0.602, p < 0.05) and C:N (path coefficient = −0.759, p < 0.001). Soil pH and C:N ratio declines were observed during forest secondary succession and were found to be inversely related to soil EMF. Furthermore, soil pH was found to be inversely related to bacterial diversity. The SEM analysis explained 88.2% of the variation in soil multifunctionality. The findings suggested that keystone plant species played a key function in regulating the variations of soil bacterial community and EMF (total effect = 0.813). Our study clarified the critical functions of keystone species in driving soil bacterial diversity and multifunctionality during forest succession and provided a new perspective on the relationship between above‐ and below‐ground. [ABSTRACT FROM AUTHOR]

Background: Epidemiological evidence shows a robust relationship between cognitive dysfunction and type 2 diabetes mellitus (T2DM). This study identified major risk factors that might prevent or ameliorate T2DM-associated cognitive dysfunction in the realm of clinical practice. Methods: Using Mini-mental State Examination (MMSE) in the light of education level, we identified older adults with T2DM on admission aged 50 and above. We conducted this case–control study when eligible participants were divided into Cognitively Normal (CN) group and Cognitively Impaired (CI) group. Analytical data referred to demographic characteristics, clinical features, fluid biomarkers, and scale tests. Results: Of 596 records screened, 504 cases were included in the final analysis. Modified multivariate logistic regression analysis verified that homocysteine (OR = 2.048, 95%CI = 1.129–3.713), brain infarction (OR = 1.963, 95%CI = 1.197–3.218), dementia (OR = 9.430, 95%CI = 2.113–42.093), education level (OR = 0.605, 95%CI = 0.367–0.997), severity of dependence (OR = 1.996, 95%CI = 1.397–2.851), creatine kinase (OR = 0.514, 95%CI = 0.271–0.974) were significant risk factors of incident T2DM-related cognitive dysfunction in patients of advanced age. Conclusion: Our study supported a robust relationship between T2DM and cognitive dysfunction. Our results provide clinicians with major risk factors for T2DM-related cognitive dysfunction, in particular the protective role of creatine kinase. [ABSTRACT FROM AUTHOR]

Autumn phenology plays a key role in regulating the terrestrial carbon and water balance and their feedbacks to the climate. However, the mechanisms underlying autumn phenology are still poorly understood, especially in subtropical forests. In this study, we extracted the autumn photosynthetic transition dates (APTD) in subtropical China over the period 2003–2017 based on a global, fine‐resolution solar‐induced chlorophyll fluorescence (SIF) dataset (GOSIF) using four fitting methods, and then explored the temporal–spatial variations of APTD and its underlying mechanisms using partial correlation analysis and machine learning methods. We further predicted the APTD shifts under future climate warming conditions by applying process‐based and machine learning‐based models. We found that the APTD was significantly delayed, with an average rate of 7.7 days per decade, in subtropical China during 2003–2017. Both partial correlation analysis and machine learning methods revealed that soil moisture was the primary driver responsible for the APTD changes in southern subtropical monsoon evergreen forest (SEF) and middle subtropical evergreen forest (MEF), whereas solar radiation controlled the APTD variations in the northern evergreen‐broadleaf deciduous mixed forest (NMF). Combining the effects of temperature, soil moisture and radiation, we found a significantly delayed trend in APTD during the 2030–2100 period, but the trend amplitude (0.8 days per decade) was much weaker than that over 2003–2017. In addition, we found that machine learning methods outperformed process‐based models in projecting APTD. Our findings generate from different methods highlight that soil moisture is one of the key players in determining autumn photosynthetic phenological processes in subtropical forests. To comprehensively understand autumn phenological processes, in‐situ manipulative experiments are urgently needed to quantify the contributions of different environmental and physiological factors in regulating plants' response to ongoing climate change. [ABSTRACT FROM AUTHOR]

Background: Schima genus of Theaceae is confined to subtropics and tropics of South, East and Southeast Asia. Thirteen species of Schima are distributed in subtropical China. Many of them appear as dominant canopy species in the subtropical forests. To date, Schima species richness distribution patterns of China have remained unknown. Meanwhile, there has been a longtime debate as to whether forests dominated by Schima species are early or late successional forests. We aim to clarify Schima species richness patterns and these species' roles in the forest succession and regeneration dynamics of the subtropical ecosystem in Yunnan Province, China. Method: We mapped Schima species richness distribution patterns in China. Based on 71 vegetation plots, we analyzed forest characteristics, population structure, and regeneration dynamics of Schima species in Yunnan. Results: Yunnan was found to harbor the greatest richness and the highest rarity-weighted richness of Schima species in the subtropical regions of China. We classified five primary and six secondary forest types containing Schima species as one of dominants. Yunnan had the high floristic diversity and varying stand structure of forests containing Schima species. The Schima species studied generally had a sporadic regeneration type and a long life-span. Four species (Schima argentea, Schima villosa, Schima sinensis, Schima sericans) were shade-intolerant. But three species (Schima noronhae, Schima khasiana and Schima wallichii) were considered as bi-modal type species having shade-intolerant and shade-tolerant traits. Schima noronhae was seen to be a top dominant in late successional forests, while S. wallichii was found as a top-dominant in early or middle or late successional forests. S. khasiana, Schima villosa, Schima sinensis usually appeared as a top dominant in early or middle successional secondary forests, though they also presented as a second dominant in late-successional forests. Schima argentea and Schima sericans dominated only in the early or middle/seral successional forests. Schima species' regeneration establishment depended mainly on forest canopy gap formation through moderate human and natural disturbances. Conclusions: Yunnan has high species richness and rarity-weighted richness of Schima. Both moderate human and natural disturbances have provided regeneration niches for Schima species. Some of the Schima species studied as a second dominant (rare as the top-dominant) present in the late-successional forests. Some of them are more often as the top-dominant in early or middle successional forests, where as time goes by the dominance of Schima species would be replaced by their associated dominant taxa such as Castanopsis species. [ABSTRACT FROM AUTHOR]

• Afforestation could attain higher EMF and multiple functions compared to savanna. • Planted species identity was crucial to successful afforestation. • Soil microbial diversity, but not plant species richness, drove EMF and multiple functions. • Soil microbial network complexity played an important role in maintaining EMF and multiple functions. Increasing aridity over the last six decades has resulted in severe degradation of ecosystem functioning and structure in the dry-hot valley savanna. It remains largely uncertain whether afforestation could recover the ecosystem multifunctionality (EMF) of the previous savanna in this region. Here, we discern key factors maintaining EMF and several specific ecosystem functions in a dry-hot valley in southwest China. We recorded plant traits, soil properties, enzymatic activity, and microbial community structure across 70 plots which included six plantations and one savanna. Afforestation could restore the EMF level of savanna by increasing individual ecosystem functions. However, not all plantations could attain the EMF level (5.29 on average) of the savanna and species identity was important for recovery in EMF and multiple ecosystem functions. Soil microbial diversity, but not plant species richness, drove improvements in EMF and multiple ecosystem functions following afforestation in the savanna. Soil fungal network complexity was the most important regulator of EMF (standardized total effect (STE) = -0.484, P < 0.01), plant biomass (STE = 0.34, P < 0.05) and soil organic carbon (SOC) stock (STE = -0.527, P < 0.01), and soil nutrients (STE = -0.7, P < 0.01), and soil fungal diversity was found to have an indirect effect on EMF (STE = 0.428, P < 0.01), SOC stock (STE = 0.355, P < 0.01), soil nutrients(STE = 0.315, P < 0.01), and decomposition (STE = 0.46, P < 0.01). Soil bacterial network complexity was related to carbon cycling and decomposition. Soil pH and soil water content played important roles in maintaining EMF and multiple ecosystem functions. Our study highlights that soil microbial diversity and network complexity are important predictors driving EMF and multiple ecosystem functions following afforestation in the dry-hot valley savanna. [ABSTRACT FROM AUTHOR]

• Increasing woodland use intensity (WUI) had significant impacts on soil EMF. • WUI can indirectly affect soil EMF through microbial diversity and network complexity. • Soil EMF was regulated by soil microbial diversity and network complexity. • Soil water content mainly affected EMF both in the dry and wet seasons. Global change (e.g., woodland use change) affects ecosystem functioning directly by modifying various physicochemical processes and indirectly by altering biological metabolism and interactions. To determine whether woodland use intensity (WUI) affects soil ecosystem multifunctionality (EMF) via microbial diversity and network complexity and whether the dry and wet season drivers are the same. We analyzed the relationships of soil EMF to soil microbial (bacteria and fungi) diversity and network complexity, considering the WUI in the monsoon evergreen broad-leaved forest in dry and wet seasons in subtropical China. The findings showed that with increasing of WUI, soil microbial (bacteria and fungi) diversity increased, whereas soil EMF decreased. The microbial network complexity decreased in the dry season but increased in the wet season. Soil EMF was jointly regulated by indirect effects from WUI in addition to microbial diversity and network complexity. WUI and abiotic factors can indirectly affect soil EMF through microbial diversity and network complexity, among which soil water content is the main environmental factor affecting soil EMF in dry season, and fungal diversity is the main factor affecting soil EMF in wet season. In addition to demonstrating how multiple anthropogenic drivers differ in their impact via different pathways on soil EMF components, our results will facilitate the prediction of ecosystem responses to multiple simultaneous environmental changes. [ABSTRACT FROM AUTHOR]

• Rare species exhibited higher functional richness and functional evenness; • Functional divergence has the greatest impact on ecosystem multifunctionality; • Rare species contribute more to ecosystem multifunctionality from a functional view. Global environmental change and increased human activities have led to rare species being given vulnerable status, as well as species losses and extinctions in recent years. However, most of the species in the community are rare species and they usually harbor unique functional traits that disproportionately contribute to community functional diversity. Numerous studies have also shown that functional diversity is a better predictor of ecosystem functioning than species diversity. Consequently, the evaluation of functional diversity of rare species and their contribution to ecosystem function is essential for the conservation of rare species. In this study, differences in functional diversity between rare and common plant species were analyzed based on functional diversity indices and species richness metrics in 30 1-ha plots comprising monsoonal evergreen broad-leaved forest in Pu'er City in the Yunnan Province of China. The roles of functional diversity of rare and common species in affecting ecosystem functions were also evaluated, in addition to the extent that either species group contributes to ecosystem functions or multifunctionality. The results indicated that functional diversity metrics including functional evenness and functional richness of rare species were higher than for common species in this subtropical forest. In addition, the functional diversity indices of rare species contributed greater to most ecosystem functions compared to those of common species. Moreover, the functional divergence of both rare and common species exerted obvious effects on ecosystem multifunctionality, although rare species exerted greater overall contributions. Rare species in the forest community of this study exhibited higher functional diversity and played a more important role in ecosystem multifunctionality via their diverse functional traits. Based on these results, it is necessary to focus greater conservation efforts on rare plants in a community. [ABSTRACT FROM AUTHOR]

Soil microbial communities play an important role in maintaining the ecosystem during forest secondary succession. However, the underlying mechanisms that drive change in soil microbial community structures during secondary succession remain poorly defined in species-rich subtropical coniferous forests. In this study, Illumina high-throughput sequencing was used to analyze the variations in soil microbial community structures during forest secondary succession in subtropical coniferous forests in China. The role of soil properties and plant diversity in affecting soil bacterial and fungal communities was determined using random forest and structural equation models. Highly variable soil microbial diversity was observed in different stages of secondary succession. Bacterial community diversity rose from early to middle and late successional stages, whereas fungal community diversity increased from early to middle successional stages and then declined in the late stage. The relative abundance of Acidobacteria, Gemmatimonadetes, Eremiobacterota(WPS-2), Rokubacteria, and Mortierellomycota increased during succession, whereas the relative abundance of Ascomycota and Mucoromycota decreased. The community composition and diversity of the soil microbial community were remarkably influenced by plant diversity and soil properties. Notably, tree species richness (TSR) displayed a significant and direct correlation to the composition and diversity of both bacterial and fungal communities. The carbon-to-nitrogen (C:N) ratio had a direct impact on the bacterial community composition and diversity, and pH had a marked impact on the fungal community composition and diversity. Furthermore, succession stage and plant diversity indirectly impacted the composition and diversity of soil bacterial and fungal communities via soil properties. Overall, it can be concluded that soil intrinsic properties and plant diversity might jointly drive the changes in soil microbial community composition and diversity during secondary succession of subtropical coniferous forests. [ABSTRACT FROM AUTHOR]

• Species richness drove mainly ecosystem multifunctionality in a subtropical coniferous forest in southwest, China. • Stand structural complexity mediated relationship between species richness and ecosystem multifunctionality. • Total woody species abundance and dominant species abundance indicated little effect on shaping ecosystem multifunctionality. Forests can provide multiple ecosystem functions simultaneously that are related to biomass production, soil carbon stock, and nutrient cycling, and plant diversity is often important for the maintenance of ecosystem multifunctionality (EMF). However, the underlying mechanisms involved in regulating relationships between species richness and abundance and EMF in a subtropical coniferous forest still remain unclear. Using a randomization test and structural equation model, we show that multiple plant diversity attributes, stand structural complexity, dominant species, and soil conditions affect EMF from 94 plots in Pinus kesiya dominant stands in southwest China. Our results indicate that the direct effects of species richness on EMF were stronger than the effects of woody individual abundance, and species richness increased with increasing EMF. By contrast, EMF declined with increasing total woody species abundance, while functional diversity and dominant species abundance did not exhibit significant effects on EMF. However, Castanopsis echidnocarpa abundance indirectly increased EMF via species richness and total woody species abundance. Simultaneously, our findings suggest that stand structural complexity mediated the relationship between plant diversity and EMF, and species richness, total woody species abundance, and EMF increased strongly with increasing stand structural complexity. Higher soil pH and soil water content were associated with greater stand structural complexity and EMF, which were important drivers in explaining variation in EMF. Our results show that higher species richness promoted EMF provisioning, and provide critical insights to predicting the possible consequences of EMF with a change in biotic and abiotic factors. [ABSTRACT FROM AUTHOR]

• Woody species richness was the main driver in shaping EMF and function indices. • Fungal diversity played an important role in driving EMF depending on main functional guilds. • Phylogenetic diversity indicated significant positive effect on the water regulation. • Multiple biodiversity attributes and soil conditions determined the supply of multiple ecosystem functions. Various biodiversity attributes contribute to ecosystem multifunctionality (EMF) in different ways in terrestrial ecosystems. The relative influence of biodiversity and abiotic factors in driving EMF simultaneously remains relatively unclear. We evaluated the effects of woody species richness along with phylogenetic, functional, fungal, and bacterial diversity as well as abiotic factors on EMF. The analysis also included a review of function indices (including biomass production, water regulation, carbon stock, and nutrient cycling) along the elevation gradient in the Jinsha River valley, southwestern China, based on the bivariate relationship, random forest model, structural equation model (SEM), randomization tests, and redundancy analysis. The results showed that EMF increased with increases in woody species richness, phylogenetic diversity, elevation, and soil water content, while it decreased with increases in bacterial diversity and soil pH. The random forest model showed that elevation, soil pH, soil water content, and woody species richness made the main contribution to EMF and function indices. Further analysis using SEM confirmed these results. Indeed, woody species richness played a relatively important role in driving EMF, biomass production, carbon stock, and nutrient cycling compared to other diversity metrics. Dominant species contributed differently to the EMF and functions. However, phylogenetic diversity also appeared to have a positive effect on water regulation. Simultaneously, as a belowground trophic group, fungal diversity played a vital role in shaping EMF, biomass production, and nutrient cycling, which may be assigned to a change of arbuscular mycorrhizal fungi and ectomycorrhizal fungi along the elevation gradient. In addition, abiotic factors regulated the relationship between biodiversity and EMF. Elevation, soil water content, and soil pH appeared to have direct and indirect effects on the EMF and function indices. Woody species richness, fungal diversity, soil water content, soil pH, and elevation jointly mediated EMF in the Jinsha River valley, whereas woody species diversity was the main driver of EMF and other function indices following the complex environmental conditions. Our result should be useful for land managers involved in ecological restoration in the Jinsha River valley, where biodiversity and soil quality will determine the supply of multiple ecosystem functions. [ABSTRACT FROM AUTHOR]

[Display omitted] • Converting primary forest to agricultural production decreased fungal, bacterial, and total microbial residue C. • Soil fungal abundance increased microbial residue C accumulation. • Soil bacterial abundance declined fungal and total microbial residue C accumulation. • Soil fertility improved fungal, bacterial, and total microbial residue C accumulation. Soil microbes mediate soil organic carbon (SOC) storage by affecting microbial residue carbon (C) in terrestrial ecosystems, a main source of SOC. However, how microbial residue C accumulation changes during the conversion of subtropical primary forest to plantations and the role of soil microbial community structure in regulating these changes remain unclear. Here, effects of conversion from forest on microbial residue C accumulation in three plantations, including tea (Camellia sinensis var. assamica), walnut (Juglans regia), and macadamia (Macadamia integrifolia). We assessed amino sugars content and the relative importance of soil microbial community structure, soil fertility, and aboveground biomass in four forest types in southwest Yunnan province, China. Our results show that total microbial residue C accounted for 27.8 % of SOC on average across all forest types, and fungal residue C contributed more to SOC than bacterial residue C across different forest types. Conversion from primary forest decreased fungal, bacterial, and total microbial residue C content in all plantation types except tea. Microbial residue C contents was significantly lower in the macadamia plantation than in the primary forest and the tea plantation. Fungal and total microbial residue C content increased with increasing soil microbial community composition, soil fungal abundance, and soil fertility. Soil fertility regulated fungal, bacterial, and total microbial residue C accumulation, which was major determinant of microbial residue C via its influence on soil fungal and bacterial abundance. Overall, we found that soil fungal abundance contributed more to microbial residue C accumulation than change in soil microbial community composition. We also found that soil bacterial abundance was negatively correlated with fungal and microbial residue C, while soil fungal abundance was positively related to microbial residue C accumulation. Ascomycota was most important phylum regulating microbial residue C. These findings suggest that soil fungal and bacterial abundance and soil fertility are the principal regulators of microbial residue C accumulation during the conversion from primary forest to different plantations. [ABSTRACT FROM AUTHOR]

[Display omitted] • Macadamia-based agroforestry systems influence microbial necromass C and its contribution to SOC. • Soil fungal β diversity controlled and significant negative effect over microbial necromass C and its contribution to SOC. • Woody aboveground biomass indirectly affected microbial necromass C via soil fungal β diversity. Agroforestry management practices governed soil organic carbon (SOC) and microbial community structure in terrestrial ecosystems, yet the effect of these practices on microbial necromass carbon (C) remain poorly understood in a subtropical region. Here, we compared the differences in fungal, bacterial, and microbial necromass C (indicated by amino sugars) and their contributions to SOC among different forest types including macadamia monoculture plantation (MMP) and macadamia-based agroforestry systems intercropping with dasheen (MDAS), konjac (MKAS), and maize (MMAS) in the Lincang city, southwest Yunnan province, China, and assessed the impact of aboveground biomass, soil fertility, and soil microbial community structure on microbial necromass C and its contribution to SOC. Compared with monoculture plantation, macadamia-based agroforestry decreased SOC, and changed significantly soil microbial α diversity, β diversity, and microbial necromass C and its contribution to SOC (P < 0.01). Microbial necromass C and its contribution to SOC were no significant difference between MMP and MMAS. MDAS and MKAS had lower microbial necromass C than MMP (35.11 % and 63.62 %, respectively). SOC increased with increasing soil fungal and microbial necromass C among the agroforestry systems. Soil fertility was the most important factor affecting fungal (41.45 %), bacterial (33.84 %), and microbial necromass C (40.63 %). Importantly, soil fertility and fungal β diversity directly negatively affected soil fungal and microbial necromass C and their contributions to SOC. Furthermore, woody aboveground biomass affected microbial necromass C directly or indirectly via soil fungal β diversity. Overall, our findings suggest that soil fungal β diversity drove microbial necromass C accumulation and its contribution to SOC in a macadamia-based agroforestry systems, which reveal that sowing crop may be key considerations in mitigating climate change. [ABSTRACT FROM AUTHOR]

Identifying and protecting refugia is a priority for conservation management under projected anthropogenic climate change. We have two main objectives: the first is to explore the spatial (East Asia) and temporal (Last Glacial Maximum to year 2070) distribution patterns of dominant Castanopsis species of evergreen broad-leaved forests, also the relation with their niche breadths; the second is to identify long-term stable refugia for preserving these species and provide a framework of conservation strategies. We find that there is an extraordinary richness with 32 dominant Castanopsis species, and they form both a geographically and climatically almost unbroken connection from ca. 5°N to 38°N, having thus ecological significance. During the Mid-Holocene and, particularly, the Last Glacial Maximum, the predicted suitable areas of the species as a whole were larger than those in the present. By 2070, potentially suitable areas with high richness of dominant Castanopsis species will be reduced by 94.5 % on average. No correlation between species niche breadths and distribution ranges is found, which could be due to regional climate stability. Mountains of southwestern and southern Yunnan in China are identified as climatically long-term stable refugia for 7–9 Castanopsis species. We recommend that these refugia have the highest priority of conservation to prevent their extinction. Our suggested urgent measures include improving the effectiveness of currently protected Castanopsis species and expanding the network of protected areas to cover a larger fraction of the refugia, as well as ensuring Castanopsis species natural regeneration potential in fragmented and natural secondary forest areas. [ABSTRACT FROM AUTHOR]

A key aspect of global forest management, woodland use intensity (WUI) greatly affects the composition and diversity of soil microbial communities, thereby affecting multiple ecosystem functions and services. However, the effects of WUI on soil microbial community composition and enzymatic activities remains unclear. The effects of anthropomorphic alterations to a natural monsoon evergreen broad-leaved forest in terms of the composition and diversity of soil fungal and bacterial communities, was investigated at a site in Yunnan Province, Southwest China. Soil microbial communities were assessed under four levels of disturbance with increasing levels of WUI: (i) none, undisturbed forest (control), (ii) light, naturally-regenerated Pinus kesiya Royle ex Gordon forest, (iii) intermediate, shrub and grassland communities formed through grazing, and (iv) severe, continuously managed coffee (Coffea arabica L.) plantations. With increasing WUI, the diversity of soil fungal and bacterial communities increased, while similarities in community composition decreased for fungi but increased for bacteria. Among fungal functional guilds, ectomycorrhizal fungi decreased significantly with increasing WUI, whereas saprotrophic fungi (undefined, wood, and soil saprotrophs) increased significantly. The species richness of woody plants remarkably affected fungal functional guilds. Ectomycorrhizal fungi interacted in a synergistic manner with the fungal network structure. Significantly affecting microorganismal network structure, WUI increases led to more homogeneous networks with less integration within modules within the microbial community. The WUI strongly altered hub identity and module composition in the microbial community. According to structural equation models, WUI had direct positive effects on soil fungal community composition via its effects on plant species richness. The diversity of bacterial and fungal communities and composition of bacterial communities were jointly regulated by the indirect effects of plant species richness and soil nutrients (including enzyme activity). Deterministic processes largely determined the composition of soil fungal and bacterial communities. This study highlights the importance of maintaining the diversity of soil fungal and bacterial communities despite changes in woodland use to sustain ecosystem functions. These results can be used to develop management practices in subtropical forests and help sustain plant and soil microbial diversity at levels sufficient to maintain long-term ecosystem function and services., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier B.V. All rights reserved.)