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Tree species diversity is assumed to be an important component in managing forest ecosystems because of effects on multiple functions or ecosystem multifunctionality. However, the importance of tree diversity in determining multifunctionality in structurally complex subtropical forests relative to other regulators (e.g., soil microbial diversity, stand structure, and environmental conditions) remains uncertain. In this study, effects of aboveground (species richness and functional and structural diversity) and belowground (bacterial and fungal diversity) biodiversity, functional composition (community-weighted means of species traits), stand structure (diameter at breast height and stand density), and soil factors (pH and bulk density) on multifunctionality (including biomass production, carbon stock, and nutrient cycling) were examined along a tree diversity gradient in subtropical forests. The community-weighted mean of tree maximum height was the best predictor of ecosystem multifunctionality. Functional diversity explained a higher proportion of the variation in multifunctionality than that of species richness and fungal diversity. Stand structure -played an important role in modulating the effects of tree diversity on multifunctionality. The work highlights that species composition and maximizing forest structural complexity are effective strategies to increase forest multifunctionality while also conserving biodiversity in the management of multifunctional forests under global environmental changes.

Enhancing knowledge on the role of evolutionary history during forest succession and its relationship with ecosystem function is particularly relevant in the context of forest landscape restoration for climate change mitigation and adaptation.We used fine resolution vegetation and environmental data (soil, elevation and slope) from two large‐scale surveys (320 × 1000 m2 plots in two 10 km × 10 km blocks) in the Upper Mekong to quantify (1) the role of abiotic and biotic (species interactions) factors in community assembly processes and (2) the effect of biodiversity, environmental factors and forest succession on above‐ground biomass (AGB).We found strong correlation between soil fertility and community structure in the early successional seres, while species interactions played an increasingly important role in older seres, presumably due to species complementary.We detected a significant relationship between AGB and phylogenetic diversity, elevation and soil fertility across successional gradients. Within successional stages, soil fertility was not significantly associated with AGB, while elevation was significantly associated with AGB only in forest <100 years old. Phylogenetic diversity was positively correlated with AGB in the young secondary forest (< 15 years old) but not significantly associated with AGB in older seres.Synthesis. Our results support the hypothesis that abiotic filtering influences species assembly in the initial stages of forest succession, while biotic interactions dominate community assembly processes in older seres. We found that phylogenetic diversity, soil fertility and elevation gradients were strongly predictive of AGB in a secondary tropical montane forest in Southeast Asia. However, elevation may reflect other underlying abiotic gradients, such as water availability. Phylogenetic diversity was significantly associated with AGB only in youngest seres (<15 years old). Considering phylogenetic diversity in restoration plantings and the management of forests younger than 15 years old could enhance forest biomass and the climate mitigation function forest landscape restoration. [ABSTRACT FROM AUTHOR]

The tree growth and mortality trade-off is well documented and plays a key role in forests by forming the basis of many ecosystem processes and contributing to tree species coexistence. One area that requires further understanding is how the growth-mortality trade-off is influenced by biotic and abiotic interactions in the forest. In this study, we used a 5-year interval of tree growth and mortality demographic data from a 9-ha forest dynamics plot in a temperate old-growth Chinese forest to address two questions, (1) What is the nature of the growth-mortality trade-off among species in this forest? (2) Are there differences between the responses of tree growth and mortality to local neighborhood variables, both biotic and abiotic? Specifically, do these responses vary among species and with tree size? For the first question, we hypothesized that, within species, mortality rate would be negatively correlated with growth rate, whereas among species it would be positively correlated. For the second question, we expected biotic and abiotic factors to both be important for tree mortality; but expected biotic factors to be more important than abiotic factors for tree growth. The responses of tree growth and mortality to local neighborhood variables, both biotic and abiotic, varied among species. Abiotic factors were more important than biotic factors for small trees; biotic variables were stable with tree size for both small and large trees. Our results showed that there were differences between the responses of tree growth and mortality to local neighborhood variables (i.e., biotic and abiotic) in this temperate forest community. The responses of tree mortality to local neighborhood variables strongly varied across species. Abiotic factors were only important for the growth of small trees. Biotic factors were stable with tree size for growth of small and large trees, but not for mortality. Mortality was negatively correlated with growth for large trees within species; growth-mortality trade-off among species was found to be more accentuated for small trees. The responses of tree mortality to local neighborhood variables differed strongly across species, whereas the responses of tree growth to local neighborhood variables varied among size classes. Tree growth and mortality is tightly correlated both within (negatively) and among species (positively), and their relationships are both size dependent in this temperate forest. Our findings highlight that differential responses of tree growth and mortality to local neighborhood variables continue to shape the forest community well after sapling establishment in this temperate forest community. [ABSTRACT FROM AUTHOR]

Independent methods of geological and molecular-biological chronologies have made it possible to define generally corresponding stages in the geological and biological evolution of the environments and communities of Lake Baikal since the Late Cretaceous, i.e., during the last 70 myr. All the abiotic elements drastically changed during geological evolution, with destruction of existing and formation of new natural complexes. Nevertheless, some specific zones retained relicts of former settings. The resulting present-day natural complex includes elements of different ages and geneses. Similar to different natural zones of the present-day Earth, which are populated by different biocoenoses, stages in the development of abiotic elements are also characterized by different faunal and floral assemblages. Some taxa were replaced by others, and the resulting aqueous biota of Lake Baikal includes different-age and ecologically different elements. The oldest groups of Baikal organisms appeared approximately 70 Ma ago, although the largest proportion of the lake biota started forming 4-3 Ma ago in response to the most drastic changes in the abiotic elements of the environment. The youngest taxa appeared 1.8 to 0.15 Ma ago, i.e., during the period when superdeep lake environments and mountainous glaciations were developing. The chronological coincidence of main stages in development of abiotic and biotic elements of the nature indicates their relationships. Particular transformations of abiotic elements and the probable mechanism of their influence on the evolution of living communities are also considered. [ABSTRACT FROM AUTHOR]