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Biodiversity plays a fundamental role in provisioning and regulating forest ecosystem functions and services. Above-ground (plants) and below-ground (soil microbes) biodiversity could have asynchronous change paces to human-driven land-use impacts. Yet, we know very little how they affect the provision of multiple forest functions related to carbon accumulation, water retention capacity and nutrient cycling simultaneously (i.e. ecosystem multifunctionality; EMF). We used a dataset of 22,000 temperate forest trees from 260 plots within 11 permanent forest sites in Northeastern China, which are recovering from three post-logging disturbances. We assessed the direct and mediating effects of multiple attributes of plant biodiversity (taxonomic, phylogenetic, functional and stand structure) and soil biodiversity (bacteria and fungi) on EMF under the three disturbance levels. We found the highest EMF in highly disturbed rather than undisturbed mature forests. Plant taxonomic, phylogenetic, functional and stand structural diversity had both positive and negative effects on EMF, depending on how the EMF index was quantified, whereas soil microbial diversity exhibited a consistent positive impact. Biodiversity indices explained on average 45% (26%-58%) of the variation in EMF, whereas climate and disturbance together explained on average 7% (0.4%-15%). Our result highlighted that the tremendous effect of biodiversity on EMF, largely overpassing those of both climate and disturbance. While above- (β = 0.02-0.19) and below-ground (β = 0.16-0.26) biodiversity had direct positive effects on EMF, their opposite mediating effects (β = -0.22 vs. β = 0.35 respectively) played as divergent pathways to human disturbance impacts on EMF. Our study sheds light on the need for integrative frameworks simultaneously considering above- and below-ground attributes to grasp the global picture of biodiversity effects on ecosystem functioning and services. Suitable management interventions could maintain both plant and soil microbial biodiversity, and thus guarantee a long-term functioning and provisioning of ecosystem services in an increasing disturbance frequency world., (© 2021 John Wiley & Sons Ltd.)

High species diversity is generally thought to be a requirement for sustaining forest multifunctionality. However, the degree to which the relationship between species-, structural-, and trait-diversity of forests and multifunctionality depend on the context (such as stand age or abiotic conditions) is not well studied. Here, we hypothesized that context-dependency of tree species diversity, functional trait composition and stand structural attributes promote temperate forest multifunctionality including above- and below-ground multiple and single functions. To do so, we used repeated forest inventory data, from temperate mixed forests of northeast China, to quantify two above-ground (i.e. coarse woody productivity and wild edible plant biomass), five below-ground (i.e. soil organic carbon, total soil nitrogen, potassium, phosphorus and sulfur) functions, tree species diversity, individual tree size variation (CV DBH ) and functional trait composition of specific leaf area (CWM SLA ) as well as stand age and abiotic conditions. We found that tree species diversity increased forest multifunctionality and most of the single functions. Below-ground single and multifunctionality were better explained by tree species diversity. In contrast, above-ground single and multifunctionality were better explained by CV DBH . However, CWM SLA was also an additional important driver for maintaining above- and below-ground forest multifunctionality through opposing plant functional strategies. Stand age markedly reduced forest multifunctionality, tree species diversity and CWM SLA but substantially increased CV DBH . Below-ground forest multifunctionality and tree species diversity decreased while above-ground forest multifunctionality increased on steep slopes. These results highlight that context-dependency of forest diversity attributes might regulate forest multifunctionality but may not have a consistent effect on above-ground and below-ground forest multifunctionality due to the fact that those functions were driven by varied functional strategies of different plant species. We argue that maximizing forest complexity could act as a viable strategy to maximizing forest multifunctionality, while also promoting biodiversity conservation to mitigate climate change effects., 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 © 2020 Elsevier B.V. All rights reserved.)

Forests play a key role in regulating the global carbon cycle, and yet the abiotic and biotic conditions that drive the demographic processes that underpin forest carbon dynamics remain poorly understood in natural ecosystems. To address this knowledge gap, we used repeat forest inventory data from 92,285 trees across four large permanent plots (4-25 ha in size) in temperate mixed forests in northeast China to ask the following questions: (1) How do soil conditions and stand age drive biomass demographic processes? (2) How do vegetation quality (i.e., functional trait diversity and composition) and quantity (i.e., initial biomass stocks) influence biomass demographic processes independently from soil conditions and stand age? (3) What is the relative contribution of growth, recruitment, and mortality to net biomass change? Using structural equation modeling, we showed that all three demographic processes were jointly constrained by multiple abiotic and biotic factors and that mortality was the strongest determinant on net biomass change over time. Growth and mortality, as well as functional trait diversity and the community-weighted mean of specific leaf area (CWM SLA ), declined with stand age. By contrast, high soil phosphorous concentrations were associated with greater functional diversity and faster dynamics (i.e., high growth and mortality rates), but associated with lower CWM SLA and initial biomass stock. More functionally diverse communities also had higher recruitment rates, but did not exhibit faster growth and mortality. Instead, initial biomass stocks and CWM SLA were stronger predictors of biomass growth and mortality, respectively. By integrating the full spectrum of abiotic and biotic drivers of forest biomass dynamics, our study provides critical system-level insights needed to predict the possible consequences of regional changes in forest diversity, composition, structure and function in the context of global change., (© 2019 The Authors. Ecology published by Wiley Periodicals, Inc. on behalf of Ecological Society of America.)

Climate change involves modifications in both the mean and the variability of temperature and precipitation. According to global warming projections, both the magnitude and the frequency of extreme weather events are increasing, thereby increasing climate variability. The previous studies have reported that climate warming tends to decrease biodiversity and the temporal stability of community primary productivity (i.e., community stability), but the effects of the variability of temperature and precipitation on biodiversity, community stability, and their relationship have not been clearly explored. We used a long-term (from 1982 to 2014) field data set from a temperate grassland in northern China to explore the effects of the variability of mean temperature and total precipitation on species richness, community stability, and their relationship. Results showed that species richness promoted community stability through increases in asynchronous dynamics across species (i.e., species asynchrony). Both species richness and species asynchrony were positively associated with the residuals of community stability after controlling for its dependence on the variability of mean temperature and total precipitation. Furthermore, the variability of mean temperature reduced species richness, while the variability of total precipitation decreased species asynchrony and community stability. Overall, the present study revealed that species richness and species asynchrony promoted community stability, but increased climate variability may erode these positive effects and thereby threaten community stability.