Fungi are crucial for terrestrial ecosystems, yet the role of fungal diversity in ecosystem functions remains unclear. We synthesize fungal biodiversity and ecosystem function (BEF) relationships, focusing on plant biomass production, carbon storage, decomposition, and pathogen or parasite resistance. The observed BEF relationships for these ecosystem functions vary in strength and direction, complicating generalizations. Strong positive relationships are generally observed when multiple ecosystem functions are addressed simultaneously. Often, fungal community composition outperforms species richness in predicting ecosystem functions. For more comprehensive fungal BEF research, we recommend studying natural communities, considering the simultaneous functions of a broader array of fungal guilds across spatiotemporal scales, and integrating community assembly concepts into BEF research. For this, we propose a conceptual framework and testable hypotheses.

• Keywords
• biodiversity, ecosystem function, fungal diversity, multifunctionality,
• MeSH
• Biodiversity * MeSH
• Biomass MeSH
• Ecosystem * MeSH
• Fungi * physiology   MeSH
• Plants microbiology   MeSH
• Publication type
• Journal Article MeSH
• Review MeSH

Global biodiversity and ecosystem service models typically operate independently. Ecosystem service projections may therefore be overly optimistic because they do not always account for the role of biodiversity in maintaining ecological functions. We review models used in recent global model intercomparison projects and develop a novel model integration framework to more fully account for the role of biodiversity in ecosystem function, a key gap for linking biodiversity changes to ecosystem services. We propose two integration pathways. The first uses empirical data on biodiversity-ecosystem function relationships to bridge biodiversity and ecosystem function models and could currently be implemented globally for systems and taxa with sufficient data. We also propose a trait-based approach involving greater incorporation of biodiversity into ecosystem function models. Pursuing both approaches will provide greater insight into biodiversity and ecosystem services projections. Integrating biodiversity, ecosystem function, and ecosystem service modeling will enhance policy development to meet global sustainability goals.

• Keywords
• biodiversity, biodiversity–ecosystem function relationships, ecosystem function, ecosystem services, modeling, sustainability, trait-based modeling,
• Publication type
• Journal Article MeSH
• Review MeSH

While biodiversity is expected to enhance multiple ecosystem functions (EFs), the different roles of multiple biodiversity dimensions remain difficult to disentangle without carefully designed experiments. We sowed plant communities with independent levels of functional (FD) and phylogenetic diversities (PD), combined with different levels of fertilization, to investigate their direct and indirect roles on multiple EFs, including plant-related EFs (plant biomass productivity, litter decomposability), soil fertility (organic carbon and nutrient pool variables), soil microbial activity (respiration and nutrient cycling), and an overall multifunctionality. We expected an increase in most EFs in communities with higher values of FD and/or PD via complementarity effects, but also the dominant plant types (using community weighted mean, CWM, independent of FD and PD) via selection effects on several EFs. The results showed strong direct effects of different dimensions of plant functional structure parameters on plant-related EFs, through either CWM or FD, with weak effects of PD. Fertilization had significant effects on one soil microbial activity and indirect effects on the other variables via changes in soil abiotic properties. Dominant plant types and FD showed only indirect effects on soil microbial activity, through litter decomposition and soil abiotic properties, highlighting the importance of cascading effects. This study shows the relevance of complementary dimensions of biodiversity for assessing both direct and cascading effects on multiple EFs.

• Keywords
• biodiversity effect, ecosystem functioning, functional diversity, litter decomposition, multifunctionality, phylogenetic diversity, plant-soil interaction, soil abiotic properties,
• MeSH
• Biodiversity MeSH
• Ecosystem * MeSH
• Phylogeny MeSH
• Soil * chemistry   MeSH
• Soil Microbiology MeSH
• Plants MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Soil * MeSH

The availability of carbon (C) from high levels of atmospheric carbon dioxide (CO2 ) and anthropogenic release of nitrogen (N) is increasing, but these increases are not paralleled by increases in levels of phosphorus (P). The current unstoppable changes in the stoichiometries of C and N relative to P have no historical precedent. We describe changes in P and N fluxes over the last five decades that have led to asymmetrical increases in P and N inputs to the biosphere. We identified widespread and rapid changes in N:P ratios in air, soil, water, and organisms and important consequences to the structure, function, and biodiversity of ecosystems. A mass-balance approach found that the combined limited availability of P and N was likely to reduce C storage by natural ecosystems during the remainder of the 21st Century, and projected crop yields of the Millennium Ecosystem Assessment indicated an increase in nutrient deficiency in developing regions if access to P fertilizer is limited. Imbalances of the N:P ratio would likely negatively affect human health, food security, and global economic and geopolitical stability, with feedbacks and synergistic effects on drivers of global environmental change, such as increasing levels of CO2 , climatic warming, and increasing pollution. We summarize potential solutions for avoiding the negative impacts of global imbalances of N:P ratios on the environment, biodiversity, climate change, food security, and human health.

• Keywords
• anthropogenic global shifts, biodiversity, biospheric N and P concentrations, ecosystem productivity, food security, human health, soil and plant N:P ratios, water,
• Publication type
• Journal Article MeSH
• Review MeSH

BACKGROUND: Alternative organism designs (i.e. the existence of distinct combinations of traits leading to the same function or performance) are a widespread phenomenon in nature and are considered an important mechanism driving the evolution and maintenance of species trait diversity. However, alternative designs are rarely considered when investigating assembly rules and species effects on ecosystem functioning, assuming that single trait trade-offs linearly affect species fitness and niche differentiation. SCOPE: Here, we first review the concept of alternative designs, and the empirical evidence in plants indicating the importance of the complex effects of multiple traits on fitness. We then discuss how the potential decoupling of single traits from performance and function of species can compromise our ability to detect the mechanisms responsible for species coexistence and the effects of species on ecosystems. Placing traits in the continuum of organism integration level (i.e. traits hierarchically structured ranging from organ-level traits to whole-organism traits) can help in choosing traits more directly related to performance and function. CONCLUSIONS: We conclude that alternative designs have important implications for the resulting trait patterning expected from different assembly processes. For instance, when only single trade-offs are considered, environmental filtering is expected to result in decreased functional diversity. Alternatively, it may result in increased functional diversity as an outcome of alternative strategies providing different solutions to local conditions and thus supporting coexistence. Additionally, alternative designs can result in higher stability of ecosystem functioning as species filtering due to environmental changes would not result in directional changes in (effect) trait values. Assessing the combined effects of multiple plant traits and their implications for plant functioning and functions will improve our mechanistic inferences about the functional significance of community trait patterning.

• Keywords
• Biodiversity–ecosystem functioning, ecological filters, ecophysiology, functional diversity, functional ecology, many-to-one mapping, species coexistence,
• MeSH
• Biodiversity MeSH
• Ecosystem * MeSH
• Phenotype MeSH
• Plant Physiological Phenomena MeSH
• Plants * MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH

Our planet is facing significant changes of biodiversity across spatial scales. Although the negative effects of local biodiversity (α diversity) loss on ecosystem stability are well documented, the consequences of biodiversity changes at larger spatial scales, in particular biotic homogenization, that is, reduced species turnover across space (β diversity), remain poorly known. Using data from 39 grassland biodiversity experiments, we examine the effects of β diversity on the stability of simulated landscapes while controlling for potentially confounding biotic and abiotic factors. Our results show that higher β diversity generates more asynchronous dynamics among local communities and thereby contributes to the stability of ecosystem productivity at larger spatial scales. We further quantify the relative contributions of α and β diversity to ecosystem stability and find a relatively stronger effect of α diversity, possibly due to the limited spatial scale of our experiments. The stabilizing effects of both α and β diversity lead to a positive diversity-stability relationship at the landscape scale. Our findings demonstrate the destabilizing effect of biotic homogenization and suggest that biodiversity should be conserved at multiple spatial scales to maintain the stability of ecosystem functions and services.

• Keywords
• biotic homogenization, grassland experiment, landscape, scale, spatial asynchrony, β diversity, γ diversity, γ stability,
• MeSH
• Biodiversity * MeSH
• Ecosystem * MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH

Biodiversity drives ecosystem processes, but its influence on deadwood decomposition is poorly understood. To test the effects of insect diversity on wood decomposition, we conducted a mesocosm experiment manipulating the species richness and functional diversity of beetles. We applied a novel approach using computed tomography scanning to quantify decomposition by insects and recorded fungal and bacterial communities. Decomposition rates increased with both species richness and functional diversity of beetles, but the effects of functional diversity were linked to beetle biomass, and to the presence of one large-bodied species in particular. This suggests that mechanisms behind observed biodiversity effects are the selection effect, which is linked to the occurrence probability of large species, and the complementarity effect, which is driven by functional differentiation among species. Additionally, beetles had significant indirect effects on wood decomposition via bacterial diversity, fungal community composition, and fungal biomass. Our experiment shows that wood decomposition is driven by beetle diversity and its interactions with bacteria and fungi. This highlights that both insect and microbial biodiversity are critical to maintaining ecosystem functioning.

• Keywords
• biodiversity-ecosystem functioning, functional diversity, insect diversity, insect-microbe interactions, wood decomposition,
• MeSH
• Bacteria MeSH
• Biodiversity MeSH
• Coleoptera * MeSH
• Wood * microbiology   MeSH
• Ecosystem MeSH
• Insecta MeSH
• Animals MeSH
• Check Tag
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH

Biodiversity-ecosystem functioning experiments (BEF) typically manipulate sown species richness and composition of experimental communities to study ecosystem functioning as a response to changes in diversity. If sown species richness is taken as a measure of diversity and aboveground biomass production as a measure of community functioning, then this relationship is usually found to be positive. The sown species richness can be considered the equivalent of a local species pool in natural communities. However, in addition to species richness, realized diversity is also an important community diversity component. Realized diversity is affected by environmental filtering and biotic interactions operating within a community. As both sown species richness and the realized diversity in BEF studies (as well as local species pool vs observed realized richness in natural communities) can differ markedly, so can their effects on the community functioning. We tested this assumption using two data sets: data from a short-term pot experiment and data from the long-term Jena biodiversity plot experiment. We considered three possible predictors of community functioning (aboveground biomass production): sown species richness, realized diversity (defined as inverse of Simpson dominance index), and survivor species richness. Sown species richness affected biomass production positively in all cases. Realized diversity as well as survivor species richness had positive effects on biomass in approximately half of cases. When realized diversity or survivor species richness was tested together with sown species richness, their partial effects were none or negative. Our results suggest that we can expect positive diversity-productivity relationship when the local species pool size is the decisive factor determining realized observed diversity; in other cases, the shape of the diversity-functioning relationship may be quite opposite.

• MeSH
• Biodiversity * MeSH
• Biomass MeSH
• Ecosystem * MeSH
• Population Dynamics MeSH
• Plants * MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH

Despite their importance, how plant communities and soil microorganisms interact to determine the capacity of ecosystems to provide multiple functions simultaneously (multifunctionality) under climate change is poorly known. We conducted a common garden experiment using grassland species to evaluate how plant functional structure and soil microbial (bacteria and protists) diversity and abundance regulate soil multifunctionality responses to joint changes in plant species richness (one, three and six species) and simulated climate change (3°C warming and 35% rainfall reduction). The effects of species richness and climate on soil multifunctionality were indirectly driven via changes in plant functional structure and their relationships with the abundance and diversity of soil bacteria and protists. More specifically, warming selected for the larger and most productive plant species, increasing the average size within communities and leading to reductions in functional plant diversity. These changes increased the total abundance of bacteria that, in turn, increased that of protists, ultimately promoting soil multifunctionality. Our work suggests that cascading effects between plant functional traits and the abundance of multitrophic soil organisms largely regulate the response of soil multifunctionality to simulated climate change, and ultimately provides novel experimental insights into the mechanisms underlying the effects of biodiversity and climate change on ecosystem functioning.

• Keywords
• bacteria, biodiversity, climate change, ecosystem functioning, environmental filtering, nutrient cycles, protist, species richness,
• MeSH
• Biodiversity MeSH
• Ecosystem MeSH
• Bacterial Physiological Phenomena MeSH
• Plant Physiological Phenomena * MeSH
• Climate Change * MeSH
• Soil * chemistry   MeSH
• Soil Microbiology * MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Soil * MeSH

Biodiversity loss poses a significant threat to ecosystem functioning. However, much of the empirical evidence for these effects is based on artificial experiments that often fail to simulate the structure of natural communities. Hence, it is still unclear whether natural diversity losses would significantly affect the functioning of "real-world" ecosystems. As subordinate and rare species constitute most of the diversity in natural communities and are often more vulnerable to local extinction, we evaluated their contribution to ecosystem functioning in a naturally species-rich grassland. We focused on two mechanisms by which they can support ecosystem functions: redundancy and complementarity. We conducted two long-term field experiments (>6 years) simulating contrasting biodiversity loss scenarios through the manual removal of plant species and measured the consequences of species loss on various ecosystem functions related to carbon dynamics. The latter were examined seasonally to explore diversity effects outside the typical peak of vegetation. We found that dominant removal led to substantial reductions in aboveground phytomass and litter production and altered the annual carbon fixation capacity of the vegetation, highlighting the pivotal role of dominant species in driving ecosystem functioning. Despite high species diversity, other species could not fully compensate for the loss of a single dominant even after more than 25 years, challenging assumptions about redundancy. Complementarity effects were not detected at the peak of vegetation but were evident in early spring and autumn when subordinate and rare species enhanced ecosystem functions. Surprisingly, belowground phytomass, soil organic carbon content, and litter decomposition were unaffected by species removal, suggesting complex interactions in belowground processes. These findings underscore the importance of dominant species in maintaining ecosystem functioning and emphasize the need for nuanced approaches to studying biodiversity loss in real-world communities. Comprehensive seasonal measurements are essential for accurately discerning the effects of biodiversity on ecosystem dynamics and informing effective conservation strategies that maintain ecosystem functioning.

• Keywords
• aboveground biomass, belowground biomass, biodiversity loss, dominant species, ecosystem functioning, litter decomposition, net ecosystem C exchange, phenological complementarity, seasonal carbon dynamics, soil organic carbon,
• MeSH
• Biodiversity * MeSH
• Time Factors MeSH
• Carbon Cycle * MeSH
• Grassland * MeSH
• Seasons * MeSH
• Plants * classification   MeSH
• Carbon * metabolism   MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Carbon * MeSH