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Soils, just like all other ecosystem compartments, change over time and, consequently, conditions for soil-inhabiting organisms are also changing, affecting their composition and diversity. Soil biodiversity is a critical component of ecosystems that supports many essential ecosystem functions and services, such as nutrient cycling, carbon sequestration, water regulation and biomass production for food, fodder, fibre and energy. However, and despite the importance of soil biodiversity for ecosystem health and human well-being, neither current state, drivers, potential consequences for ecosystem services nor options for sustainable governance of soil biodiversity are well understood. Here, we provide a framework for and argue that conducting a national assessment of soil biodiversity, albeit being a complex endeavour, is fundamental to building a baseline to understand the current state and trends of soil biodiversity, but also to identify the main drivers of change, the impacts of soil biodiversity loss and the potential pathways for conservation and sustainable governance of soil biodiversity.

Essential soil functions such as plant productivity, C storage, nutrient cycling and the storage and purification of water all depend on soil biological processes. Given this insight, it is remarkable that in modeling of these soil functions, the various biological actors usually do not play an explicit role. In this review and perspective paper we analyze the state of the art in modeling these soil functions and how biological processes could more adequately be accounted for. We do this for six different biologically driven processes clusters that are key for understanding soil functions, namely i) turnover of soil organic matter, ii) N cycling, iii) P dynamics, iv) biodegradation of contaminants v) plant disease control and vi) soil structure formation. A major conclusion is that the development of models to predict changes in soil functions at the scale of soil profiles (i.e. pedons) should be better rooted in the underlying biological processes that are known to a large extent. This is prerequisite to arrive at the predictive models that we urgently need under current conditions of Global Change.

Organismal functional strategies form a continuum from slow- to fast-growing organisms, in response to common drivers such as resource availability and disturbance. However, whether there is synchronisation of these strategies at the entire community level is unclear. Here, we combine trait data for >2800 above- and belowground taxa from 14 trophic guilds spanning a disturbance and resource availability gradient in German grasslands. The results indicate that most guilds consistently respond to these drivers through both direct and trophically mediated effects, resulting in a ‘slow-fast’ axis at the level of the entire community. Using 15 indicators of carbon and nutrient fluxes, biomass production and decomposition, we also show that fast trait communities are associated with faster rates of ecosystem functioning. These findings demonstrate that ‘slow’ and ‘fast’ strategies can be manifested at the level of whole communities, opening new avenues of ecosystem-level functional classification.

Soils provide essential ecosystem functions that are threatened by climate change and intensified land use. We explore how climate and land use impact multiple soil function simultaneously, employing two datasets: (1) observational – 456 samples from the European Land Use/Land Cover Area Frame Survey; and (2) experimental – 80 samples from Germany’s Global Change Experimental Facility. We aim to investigate whether manipulative field experiment results align with observable climate, land use, and soil multifunctionality trends across Europe, measuring seven ecosystem functions to calculate soil multifunctionality. The observational data showed Europe-wide declines in soil multifunctionality under rising temperatures and dry conditions, worsened by cropland management. Our experimental data confirmed these relationships, suggesting that changes in climate will reduce soil multifunctionality across croplands and grasslands. Land use changes from grasslands to croplands threaten the integrity of soil systems, and enhancing soil multifunctionality in arable systems is key to maintain multifunctionality in a changing climate.

Aim The Paris Climate Agreement is pursuing efforts to limit global warming to less than 2 °C in this century, but increasing evidence shows that temperatures are likely to rise up to 4.8 °C by 2100. This points to an urgent need to investigate how the temperature impact on microbial regulation will endanger soil organic matter stability under warming approaching or exceeding 2 °C. Location Southern Germany and the globe. Time Period 2010–2018. Major Taxa Studied Soil organic matter stability and microbial adaptations. Methods We analyzed soil properties and enzyme activities within (a) a long-term field experiment with soil warming to below and above 2 °C (+1.6 vs. +3.2 °C), and (b) a literature review of 213 comparable studies globally (+0–2 vs. +2–4 °C). Results The soil organic C (SOC) stock remained unchanged after 8 years under both warming magnitudes, whereas the labile C pool increased by 10% under >2 °C. Unlike the SOC pool, total N (TN) content increased by 20% under >2 °C as compared to ambient. A potential explanation for the increased TN content is linked to unbalanced processes of necromass formation and enzymatic decomposition. Warming induced faster microbial growth and turnover, but reduced catalytic efficiency and the enzyme-mediated decomposition of oligosaccharides and polypeptides. This consequently caused N accumulation in microbial necromass. Although microbial regulation can maintain SOC at stable levels, warming exceeding 2 °C will change the projected effects of temperature on soil TN pools in the future. Early action to accomplish the 2 °C temperature goal can therefore markedly reduce the likelihood that large regions will face substantial increase of SOC availability, N accumulation and related climate impacts on C and N cycling. Main Conclusions It is crucial to include microbial metabolic responses (i.e., faster microbial growth and turnover) to warming in global C and N cycle models to improve the prediction of climate w

Biodiversity drives the maintenance and stability of ecosystem functioning as well as many of nature’s benefits to people, yet people cause substantial biodiversity change. Despite broad consensus about a positive relationship between biodiversity and ecosystem functioning (BEF), the underlying mechanisms and their context-dependencies are not well understood. This proposal, submitted to the European Research Council (ERC), aims at filling this knowledge gap by providing a novel conceptual framework for integrating biotic interactions across guilds of organisms, i.e. plants and mycorrhizal fungi, to explain the ecosystem consequences of biodiversity change. The overarching hypothesis is that EF increases when more tree species associate with functionally dissimilar mycorrhizal fungi. Taking a whole-ecosystem perspective, we propose to explore the role of tree-mycorrhiza interactions in driving BEF across environmental contexts and how this relates to nutrient dynamics. Given the significant role that mycorrhizae play in soil nutrient and water uptake, BEF relationships will be investigated under normal and drought conditions. Resulting ecosystem consequences will be explored by studying main energy channels and ecosystem multifunctionality using food web energy fluxes and by assessing carbon storage. Synthesising drivers of biotic interactions will allow us to understand context-dependent BEF relationships. This interdisciplinary and integrative project spans the whole gradient from local-scale process assessments to global relationships by building on unique experimental infrastructures like the MyDiv Experiment, iDiv Ecotron and the global network TreeDivNet, to link ecological mechanisms to reforestation initiatives. This innovative combination of basic scientific research with real-world interventions links trait-based community ecology, global change research and ecosystem ecology, pioneering a new generation of BEF research and represents a significant step to

Few microbiome-based solutions for agricultural productivity, food processing and human nutrition have been successfully commercialized. A systems-based approach that considers the ecology of microbial communities may help finetune extant tools to increase their reliability while promoting innovation and greater adoption.

Nature conservation literature and policy instruments mainly focus on the impacts of human development and the benefits of nature conservation for oceans and aboveground terrestrial organisms (e.g., birds and plants) and processes (e.g., food production), but these efforts almost completely ignore the majority of terrestrial biodiversity that is unseen and living in the soil (1). Little is known about the conservation status of most soil organisms and the effects of nature conservation policies on soil systems. Yet like “canaries in the coal mine,” when soil organisms begin to disappear, ecosystems will soon start to underperform, potentially hindering their vital functions for humankind. Soil biodiversity and its ecosystem functions thus require explicit consideration when establishing nature protection priorities and policies and when designing new conservation areas. To inform such efforts, we lay out a global soil biodiversity and ecosystem function monitoring framework to be considered in the context of the post-2020 discussions of the Convention on Biological Diversity (CBD). To support this framework, we suggest a suite of soil ecological indicators based on essential biodiversity variables (EBVs) (2) (see the figure and table S3) that directly link to current global targets such as the ones established under the CBD, the Sustainable Development Goals (SDGs), and the Paris Agreement (table S1).

Aim Quantify direct and indirect relationships between soil microbial community properties (potential basal respiration, microbial biomass) and abiotic factors (soil, climate) in three major land-cover types. Location Europe. Time period 2018. Major taxa studied Microbial community (fungi and bacteria). Methods We collected 881 soil samples from across Europe in the framework of the Land Use/Land Cover Area Frame Survey (LUCAS). We measured potential soil basal respiration at 20 oC and microbial biomass (substrate-induced respiration) using an O-2-microcompensation apparatus. Soil and climate data were obtained from the same LUCAS survey and online databases. Structural equation models (SEMs) were used to quantify relationships between variables, and equations extracted from SEMs were used to create predictive maps. Fatty acid methyl esters were measured in a subset of samples to distinguish fungal from bacterial biomass. Results Soil microbial properties in croplands were more heavily affected by climate variables than those in forests. Potential soil basal respiration and microbial biomass were correlated in forests but decoupled in grasslands and croplands, where microbial biomass depended on soil carbon. Forests had a higher ratio of fungi to bacteria than grasslands or croplands. Main conclusions Soil microbial communities in grasslands and croplands are likely carbon-limited in comparison with those in forests, and forests have a higher dominance of fungi indicating differences in microbial community composition. Notably, the often already-degraded soils of croplands could be more vulnerable to climate change than more natural soils. The provided maps show potentially vulnerable areas that should be explicitly accounted for in future management plans to protect soil carbon and slow the increasing vulnerability of European soils to climate change.

Plant traits—the morphological, anatomical, physiological, biochemical and phenological characteristics of plants—determine how plants respond to environmental factors, affect other trophic levels, and influence ecosystem properties and their benefits and detriments to people. Plant trait data thus represent the basis for a vast area of research spanning from evolutionary biology, community and functional ecology, to biodiversity conservation, ecosystem and landscape management, restoration, biogeography and earth system modelling. Since its foundation in 2007, the TRY database of plant traits has grown continuously. It now provides unprecedented data coverage under an open access data policy and is the main plant trait database used by the research community worldwide. Increasingly, the TRY database also supports new frontiers of trait‐based plant research, including the identification of data gaps and the subsequent mobilization or measurement of new data. To support this development, in this article we evaluate the extent of the trait data compiled in TRY and analyse emerging patterns of data coverage and representativeness. Best species coverage is achieved for categorical traits—almost complete coverage for ‘plant growth form’. However, most traits relevant for ecology and vegetation modelling are characterized by continuous intraspecific variation and trait–environmental relationships. These traits have to be measured on individual plants in their respective environment. Despite unprecedented data coverage, we observe a humbling lack of completeness and representativeness of these continuous traits in many aspects. We, therefore, conclude that reducing data gaps and biases in the TRY database remains a key challenge and requires a coordinated approach to data mobilization and trait measurements. This can only be achieved in collaboration with other initiatives.

Soils harbor a substantial fraction of the world’s biodiversity, contributing to many crucial ecosystem functions. It is thus essential to identify general macroecological patterns related to the distribution and functioning of soil organisms to support their conservation and consideration by governance. These macroecological analyses need to represent the diversity of environmental conditions that can be found worldwide. Here we identify and characterize existing environmental gaps in soil taxa and ecosystem functioning data across soil macroecological studies and 17,186 sampling sites across the globe. These data gaps include important spatial, environmental, taxonomic, and functional gaps, and an almost complete absence of temporally explicit data. We also identify the limitations of soil macroecological studies to explore general patterns in soil biodiversity-ecosystem functioning relationships, with only 0.3% of all sampling sites having both information about biodiversity and function, although with different taxonomic groups and functions at each site. Based on this information, we provide clear priorities to support and expand soil macroecological research.

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Organismal movement is ubiquitous and facilitates important ecological mechanisms that drive community and metacommunity composition and hence biodiversity. In most existing ecological theories and models in biodiversity research, movement is represented simplistically, ignoring the behavioural basis of movement and consequently the variation in behaviour at species and individual levels. However, as human endeavours modify climate and land use, the behavioural processes of organisms in response to these changes, including movement, become critical to understanding the resulting biodiversity loss. Here, we draw together research from different subdisciplines in ecology to understand the impact of individual‐level movement processes on community‐level patterns in species composition and coexistence. We join the movement ecology framework with the key concepts from metacommunity theory, community assembly and modern coexistence theory using the idea of micro–macro links, where various aspects of emergent movement behaviour scale up to local and regional patterns in species mobility and mobile‐link‐generated patterns in abiotic and biotic environmental conditions. These in turn influence both individual movement and, at ecological timescales, mechanisms such as dispersal limitation, environmental filtering, and niche partitioning. We conclude by highlighting challenges to and promising future avenues for data generation, data analysis and complementary modelling approaches and provide a brief outlook on how a new behaviour‐based view on movement becomes important in understanding the responses of communities under ongoing environmental change.

Global change has complex eco-evolutionary consequences for organisms and ecosystems, but related concepts (e.g., novel ecosystems) do not cover their full range. Here we propose an umbrella concept of “ecological novelty” comprising (1) a site-specific and (2) an organism-centered, eco-evolutionary perspective. Under this umbrella, complementary options for studying and communicating effects of global change on organisms, ecosystems, and landscapes can be included in a toolbox. This allows researchers to address ecological novelty from different perspectives, e.g., by defining it based on (a) categorical or continuous measures, (b) reference conditions related to sites or organisms, and (c) types of human activities. We suggest striving for a descriptive, non-normative usage of the term “ecological novelty” in science. Normative evaluations and decisions about conservation policies or management are important, but require additional societal processes and engagement with multiple stakeholders.

Research on mycorrhizal interactions has traditionally developed into separate disciplines addressing different organizational levels. This separation has led to an incomplete understanding of mycorrhizal functioning. Integration of mycorrhiza research at different scales is needed to understand the mechanisms underlying the context dependency of mycorrhizal associations, and to use mycorrhizae for solving environmental issues. Here, we provide a road map for the integration of mycorrhiza research into a unique framework that spans genes to ecosystems. Using two key topics, we identify parallels in mycorrhiza research at different organizational levels. Based on two current projects, we show how scientific integration creates synergies, and discuss future directions. Only by overcoming disciplinary boundaries, we will achieve a more comprehensive understanding of the functioning of mycorrhizal associations.

It is debated whether alien plants in new environments benefit from being mycorrhizal and whether widely distributed natives and aliens differ in their associations with mycorrhizal fungi. Here, we compared whether species differing in their origin status, i.e. natives, archaeophytes (alien species introduced before the year 1500) and neophytes (introduced after the year 1500), and arbuscular mycorrhizal (AM) status (obligate, facultative, non-mycorrhizal) differ in their area of occupancy in Germany (i.e. number of occupied grid cells, each ~130km²). We used generalized linear models, incorporating main effects and up to three-way interactions combining AM status, origin status and plant functional traits. The latter were chosen to describe the possible trade-off in carbon allocation either towards the symbiosis or to other plant structures, such as storage organs (significant interactions involving traits were assumed to indicate the existence of such trade-offs). AM status significantly explained the area of occupancy of natives and neophytes - with facultative mycorrhizal species occupying the largest area in both groups - but was less pronounced among archaeophytes. Archaeophytes may have reduced dependency on AM fungi, as they are generally agricultural weeds and the symbiosis potentially becomes obsolete for plants growing in habitats providing a steady provision of nutrients. Trait interactions between AM status and other functional traits were almost exclusively detected for neophytes. While facultative mycorrhizal neophytes benefit from trade-offs with other traits related to high C cost in terms of area of occupancy, such trade-offs were almost absent among natives. This indicates that natives and neophytes benefit differently from the symbiosis and suggests that native AM fungal partners might be less important for neophyte than for native plant species or that more time is required to establish similar relationships between neophytes and native fungal s

Rare species are increasingly recognized as crucial, yet vulnerable components of Earth’s ecosystems. This is also true for microbial communities, which are typically composed of a high number of relatively rare species. Recent studies have demonstrated that rare species can have an over-proportional role in biogeochemical cycles and may be a hidden driver of microbiome function. In this review, we provide an ecological overview of the rare microbial biosphere, including causes of rarity and the impacts of rare species on ecosystem functioning. We discuss how rare species can have a preponderant role for local biodiversity and species turnover with rarity potentially bound to phylogenetically conserved features. Rare microbes may therefore be overlooked keystone species regulating the functioning of host-associated, terrestrial and aquatic environments. We conclude this review with recommendations to guide scientists interested in investigating this rapidly emerging research area.

Im Rahmen des GEWISS-Bausteinprogramms wurde das Grünbuch für eine Citizen Science-Strategie 2020 für Deutschland zusammen mit über 700 an Citizen Science interessierten Personen aus mehr als 350 Organisationen und Einzelpersonen erarbeitet.Bürgerschaftliches Engagement spielt auch in der Forschung eine immer wichtigere Rolle und kann ein Weg der Teilhabe für die verschiedensten Gruppen in unserer stark wissenschaftsbasierten Gesellschaft sein. Aktuell wird die Beteiligung von Bürgerinnen und Bürgern an wissenschaftlichen Prozessen wesentlich unter dem Stichwort „Citizen Science“ diskutiert. Über die wissenschaftlichen Erkenntnisseund Daten hinaus kann Citizen Science einen Mehrwert für die Gesellschaft erzielen: Menschen erweitern ihr Wissen über Natur, Technik, Geschichte – und lernen, wie Wissenschaft funktioniert. Sie können Daten und Ergebnisse aus der Wissenschaft besser einschätzen und auch die Grenzen wissenschaftlicher Methoden und Erkenntnisse nachvollziehen. Unabdingbar ist, dass bei allen Citizen-Science-Projektender wissenschaftliche Erkenntnisgewinn im Fokus bleibt.Dieses Grünbuch Citizen-Science-Strategie 2020 für Deutschland stellt das Verständnis, die Bedarfe und Potenziale von Citizen Science in Deutschland vor. Es reflektiert, welcher Mehrwert in den verschiedenen gesellschaftlichen Bereichen entstehen kann und wo noch nicht ausgeschöpftes Potenzial vorhanden ist. Zu deren Verwirklichung werden konkrete Vorschläge für Handlungsoptionen und Maßnahmen entwickelt, die der Stärkung von Citizen Science in Deutschland dienen und langfristig Kapazitäten für die erfolgreiche Durchführung von Citizen Science freisetzen können.An der Diskussion um die Bedeutung von Citizen Science, aber auch über Herausforderungen und Hemmnisse, haben sich viele Personen mit unterschiedlichen Hintergründen im Rahmen verschiedener Veranstaltungen und der Online-Konsultation der Strategie beteiligt. Ihnen allen möchten wir unseren Dank für die unterstützenden, kritischen und

Civic engagement plays an increasingly important role, not only in society but also in research, as one avenue for different actors to actively participate in our strongly science-based society. Currently, citizen participation in scientific processes is dis- cussed widely under the heading of “Citizen Science”. Beyond advancing scientific find- ings and large scale data provision, Citizen Science can generate significant added value for society: people can enhance their scientific literacy in fields such as nature, technology and history – and learn how science works. They are better equipped to assess scientific data and results and to understand the limitations of scientific methods and findings. The overarching focus for all Citizen Science projects is the gaining of scientific knowledge for both science and society.This Green Paper Citizen Science Strategy 2020 for Germany presents the under- standing, the requirements and the potential of Citizen Science in Germany. It re- flects on the multiple benefits of Citizen Science for different sectors of society and on options and opportunities to develop the methodology and approach. In order to real- ise this potential, the Green Paper develops 10 potential fields of action to strengthen Citizen Science in Germany and to build capacities for the successful implementation of Citizen Science programmes.During the GEWISS events, and through the online and written consultation on the Citizen Science Strategy 2020 for Germany, many participants with different back- grounds joined the discussions on the significance of Citizen Science, the challenges as well as opportunities. We are extremely grateful for all their supportive, critical and inspiring  contributions.We hope to maintain an open and transparent dialogue with all stakeholders, also in the future. This should focus on demonstrating and evaluating citizen science experiences in practice and developing success criteria to support the initiators and prom

It is still debated whether alien plants benefit from being mycorrhizal, or if engaging in the symbiosis constrains their establishment and spread in new regions. We analyzed the association between mycorrhizal status of alien plant species in Germany and their invasion success. We compared whether the representation of species with different mycorrhizal status (obligate, facultative, or non-mycorrhizal) differed at several stages of the invasion process. We used generalized linear models to explain the occupied geographical range of alien plants, incorporating interactions of mycorrhizal status with plant traits related to morphology, reproduction, and life-history. Non-naturalized aliens did not differ from naturalized aliens in the relative frequency of different mycorrhizal status categories. Mycorrhizal status significantly explained the occupied range of alien plants; with facultative mycorrhizal species inhabiting a larger range than non-mycorrhizal aliens and obligate mycorrhizal plant species taking an intermediate position. Aliens with storage organs, shoot metamorphoses, or specialized structures promoting vegetative dispersal occupied a larger range when being facultative mycorrhizal. We conclude that being mycorrhizal is important for the persistence of aliens in Germany and constitutes an advantage compared to being non-mycorrhizal. Being facultative mycorrhizal seems to be especially advantageous for successful spread, as the flexibility of this mycorrhizal status may enable plants to use a broader set of ecological strategies.

We analysed the spatial distribution patterns of plant species’ arbuscular mycorrhizal status across an intermediate geographical scale (i.e. the country of Germany) and related these distributions to environmental drivers. Three levels of arbuscular mycorrhizal status of plant species could be defined: (1) obligate arbuscular mycorrhizal species that are always colonised by mycorrhizal fungi, (2) facultative arbuscular mycorrhizal species that are colonised under some conditions but not colonised under others and (3) non-mycorrhizal species that are never found to be colonised by mycorrhizal fungi. We aimed to investigate whether plant species assemblages at the studied grid cell scale are composed of different proportions of species regarding their arbuscular mycorrhizal status, and whether the variation of these proportions can be linked to the geographical variation of ecological and environmental factors. We fitted a vector generalised additive model (VGAM) for log-ratios of proportions of plant species’ arbuscular mycorrhizal status per grid cell (2859 grid cells, each c. 130 km2). The spatially explicit plant arbuscular mycorrhizal status distribution model was based on environmental predictors related to climate, geology and land use. The spatial distribution of plant arbuscular mycorrhizal status can be explained as a function of nine environmental predictors (D2 = 0.54). Proportion of obligate arbuscular mycorrhizal plant species per grid cell increased with increasing temperature range, mean annual temperature, urban area and area of lime as geological parent material and decreased with increasing area of mixed forest and coniferous forest. Annual temperature range was by far the most important predictor. These results extend the comparative context of former studies that established relationships between mycorrhizal status and other plant characteristics at species level, including those describing species ecological requiremen

Many experiments have shown that loss of biodiversity reduces the capacity of ecosystems to provide the multiple services on which humans depend1, 2. However, experiments necessarily simplify the complexity of natural ecosystems and will normally control for other important drivers of ecosystem functioning, such as the environment or land use. In addition, existing studies typically focus on the diversity of single trophic groups, neglecting the fact that biodiversity loss occurs across many taxa3, 4 and that the functional effects of any trophic group may depend on the abundance and diversity of others5, 6. Here we report analysis of the relationships between the species richness and abundance of nine trophic groups, including 4,600 above- and below-ground taxa, and 14 ecosystem services and functions and with their simultaneous provision (or multifunctionality) in 150 grasslands. We show that high species richness in multiple trophic groups (multitrophic richness) had stronger positive effects on ecosystem services than richness in any individual trophic group; this includes plant species richness, the most widely used measure of biodiversity. On average, three trophic groups influenced each ecosystem service, with each trophic group influencing at least one service. Multitrophic richness was particularly beneficial for ‘regulating’ and ‘cultural’ services, and for multifunctionality, whereas a change in the total abundance of species or biomass in multiple trophic groups (the multitrophic abundance) positively affected supporting services. Multitrophic richness and abundance drove ecosystem functioning as strongly as abiotic conditions and land-use intensity, extending previous experimental results7, 8 to real-world ecosystems. Primary producers, herbivorous insects and microbial decomposers seem to be particularly important drivers of ecosystem functioning, as shown by the strong and frequent positive associations of their richness or abundance with multiple eco

Species diversity promotes the delivery of multiple ecosystem functions (multifunctionality). However, the relative functional importance of rare and common species in driving the biodiversity–multifunctionality relationship remains unknown. We studied the relationship between the diversity of rare and common species (according to their local abundances and across nine different trophic groups), and multifunctionality indices derived from 14 ecosystem functions on 150 grasslands across a land-use intensity (LUI) gradient. The diversity of above- and below-ground rare species had opposite effects, with rare above-ground species being associated with high levels of multifunctionality, probably because their effects on different functions did not trade off against each other. Conversely, common species were only related to average, not high, levels of multifunctionality, and their functional effects declined with LUI. Apart from the community-level effects of diversity, we found significant positive associations between the abundance of individual species and multifunctionality in 6% of the species tested. Species-specific functional effects were best predicted by their response to LUI: species that declined in abundance with land use intensification were those associated with higher levels of multifunctionality. Our results highlight the importance of rare species for ecosystem multifunctionality and help guiding future conservation priorities.

Im Rahmen des GEWISS-Bausteinprogramms wurde das Grünbuch für eine Citizen Science-Strategie 2020 für Deutschland zusammen mit über 700 an Citizen Science interessierten Personen aus mehr als 350 Organisationen und Einzelpersonen erarbeitet.Bürgerschaftliches Engagement spielt auch in der Forschung eine immer wichtigere Rolle und kann ein Weg der Teilhabe für die verschiedensten Gruppen in unserer stark wissenschaftsbasierten Gesellschaft sein. Aktuell wird die Beteiligung von Bürgerinnen und Bürgern an wissenschaftlichen Prozessen wesentlich unter dem Stichwort „Citizen Science“ diskutiert. Über die wissenschaftlichen Erkenntnisseund Daten hinaus kann Citizen Science einen Mehrwert für die Gesellschaft erzielen: Menschen erweitern ihr Wissen über Natur, Technik, Geschichte – und lernen, wie Wissenschaft funktioniert. Sie können Daten und Ergebnisse aus der Wissenschaft besser einschätzen und auch die Grenzen wissenschaftlicher Methoden und Erkenntnisse nachvollziehen. Unabdingbar ist, dass bei allen Citizen-Science-Projektender wissenschaftliche Erkenntnisgewinn im Fokus bleibt.Dieses Grünbuch Citizen-Science-Strategie 2020 für Deutschland stellt das Verständnis, die Bedarfe und Potenziale von Citizen Science in Deutschland vor. Es reflektiert, welcher Mehrwert in den verschiedenen gesellschaftlichen Bereichen entstehen kann und wo noch nicht ausgeschöpftes Potenzial vorhanden ist. Zu deren Verwirklichung werden konkrete Vorschläge für Handlungsoptionen und Maßnahmen entwickelt, die der Stärkung von Citizen Science in Deutschland dienen und langfristig Kapazitäten für die erfolgreiche Durchführung von Citizen Science freisetzen können.An der Diskussion um die Bedeutung von Citizen Science, aber auch über Herausforderungen und Hemmnisse, haben sich viele Personen mit unterschiedlichen Hintergründen im Rahmen verschiedener Veranstaltungen und der Online-Konsultation der Strategie beteiligt. Ihnen allen möchten wir unseren Dank für die unterstützenden, kritischen und

Civic engagement plays an increasingly important role, not only in society but also in research, as one avenue for different actors to actively participate in our strongly science-based society. Currently, citizen participation in scientific processes is dis- cussed widely under the heading of “Citizen Science”. Beyond advancing scientific find- ings and large scale data provision, Citizen Science can generate significant added value for society: people can enhance their scientific literacy in fields such as nature, technology and history – and learn how science works. They are better equipped to assess scientific data and results and to understand the limitations of scientific methods and findings. The overarching focus for all Citizen Science projects is the gaining of scientific knowledge for both science and society.This Green Paper Citizen Science Strategy 2020 for Germany presents the under- standing, the requirements and the potential of Citizen Science in Germany. It re- flects on the multiple benefits of Citizen Science for different sectors of society and on options and opportunities to develop the methodology and approach. In order to real- ise this potential, the Green Paper develops 10 potential fields of action to strengthen Citizen Science in Germany and to build capacities for the successful implementation of Citizen Science programmes.During the GEWISS events, and through the online and written consultation on the Citizen Science Strategy 2020 for Germany, many participants with different back- grounds joined the discussions on the significance of Citizen Science, the challenges as well as opportunities. We are extremely grateful for all their supportive, critical and inspiring  contributions.We hope to maintain an open and transparent dialogue with all stakeholders, also in the future. This should focus on demonstrating and evaluating citizen science experiences in practice and developing success criteria to support the initiators and prom

Soil biodiversity is immense, with an estimated 10–100 million organisms belonging to over 5000 taxa in a handful of soil. In spite of the importance of soil biodiversity for ecosystem functions and services, information on soil species, from taxonomy to biogeographical patterns, is incomplete and there is no infrastructure to connect pre-existing or future data. Here, we propose a global platform to allow for greater access to soil biodiversity information by linking databases and repositories through a single open portal. The proposed platform would for the first time, link data on soil organisms from different global sites and biomes, and will be inclusive of all data types, from molecular sequences to morphology measurements and other supporting information. Access to soil biodiversity species records and information will be instrumental to progressing scientific research and education. Further, as demonstrated by previous biodiversity synthesis efforts, data availability is key for adapting to, and creating mitigation plans in response to global changes. With the rapid influx of soil biodiversity data, now is the time to take the first steps forward in establishing a global soil biodiversity information platform.

Negative plant-soil feedbacks can impair seedling survival near conspecific trees and may enhance forest diversity. However, the reciprocal aspect of this relationship, the influence of tree diversity on the strengths of plant-soil feedbacks is unknown. We examined whether tree diversity can affect plant-soil feedbacks of two common temperate tree species, beech (Fagus sylvatica) and sessile oak (Quercus petraea). Soils were collected from adjacent to beech and oak trees growing in a manipulative tree diversity field experiment and used as inocula in a greenhouse experiment to determine whether increasing tree diversity could moderate the strengths of plant-soil feedbacks. We also compared plant-soil feedback responses between Q. petraea and F. sylvatica to test the hypothesis that stronger negative feedbacks contribute to the relative rarity of Q. petraea. Negative plant-soil feedbacks on seedling emergence were observed for both tree species. Emergence increased with increasing distance of the soil inocula from established trees in the field, but only for inocula taken from the low diversity treatment (monocultures) and irrespective of the inoculum source (i.e. from conspecific vs. heterospecific trees). In contrast, tree diversity had no influence on the biomass responses of seedlings for either tree species. Quercus petraea seedlings experienced negative plant-soil feedbacks in their biomass responses which cascaded up to higher trophic levels, i.e. leaf pathogen infection. Fagus sylvatica biomass responses suggested positive plant-soil feedbacks, supporting the hypothesis that the abundance of this species is less limited by interactions with natural enemies. Our results suggest that distance-dependent seedling emergence in temperate forests may depend on the diversity of tree communities and that plant-soil feedbacks may cascade up to higher trophic levels and change with the life history stage of the seedlings involved. An increased focus on the surrounding c

Biodiversity, a multidimensional property of natural systems, is difficult to quantify partly because of the multitude of indices proposed for this purpose. Indices aim to describe general properties of communities that allow us to compare different regions, taxa, and trophic levels. Therefore, they are of fundamental importance for environmental monitoring and conservation, although there is no consensus about which indices are more appropriate and informative. We tested several common diversity indices in a range of simple to complex statistical analyses in order to determine whether some were better suited for certain analyses than others. We used data collected around the focal plant Plantago lanceolata on 60 temperate grassland plots embedded in an agricultural landscape to explore relationships between the common diversity indices of species richness (S), Shannon's diversity (H'), Simpson's diversity (D1), Simpson's dominance (D2), Simpson's evenness (E), and Berger–Parker dominance (BP). We calculated each of these indices for herbaceous plants, arbuscular mycorrhizal fungi, aboveground arthropods, belowground insect larvae, and P. lanceolata molecular and chemical diversity. Including these trait-based measures of diversity allowed us to test whether or not they behaved similarly to the better studied species diversity. We used path analysis to determine whether compound indices detected more relationships between diversities of different organisms and traits than more basic indices. In the path models, more paths were significant when using H', even though all models except that with E were equally reliable. This demonstrates that while common diversity indices may appear interchangeable in simple analyses, when considering complex interactions, the choice of index can profoundly alter the interpretation of results. Data mining in order to identify the index producing the most significant results should be avoided, but simultaneously considering an

Improving our understanding of biodiversity and ecosystem functioning and our capacity to inform ecosystem management requires an integrated framework for functional biodiversity research (FBR). However, adequate integration among empirical approaches (monitoring and experimental) and modelling has rarely been achieved in FBR. We offer an appraisal of the issues involved and chart a course towards enhanced integration. A major element of this path is the joint orientation towards the continuous refinement of a theoretical framework for FBR that links theory testing and generalization with applied research oriented towards the conservation of biodiversity and ecosystem functioning. We further emphasize existing decision-making frameworks as suitable instruments to practically merge these different aims of FBR and bring them into application. This integrated framework requires joint research planning, and should improve communication and stimulate collaboration between modellers and empiricists, thereby overcoming existing reservations and prejudices. The implementation of this integrative research agenda for FBR requires an adaptation in most national and international funding schemes in order to accommodate such joint teams and their more complex structures and data needs.

Arbuscular mycorrhizal fungi (AMF) provide a number of ecosystem services as important members of the soil microbial community. Increasing evidence suggests AMF diversity is at least partially controlled by the identities of plants in the host plant neighborhood. However, much of this evidence comes from greenhouse studies or work in invaded systems dominated by single plant species, and has not been tested in species-rich grasslands. We worked in 67 grasslands spread across the three German Biodiversity Exploratories that are managed primarily as pastures and meadows, and collected data on AMF colonization, AMF richness, AMF community composition, plant diversity, and land use around focal Plantago lanceolata plants. We analyzed the data collected within each Exploratory (ALB Schwäbische Alb, HAI Hainich-Dün, SCH Schorfheide-Chorin) separately, and used variance partitioning to quantify the contribution of land use, host plant neighborhood, and spatial arrangement to the effect on AMF community composition. We performed canonical correspondence analysis to quantify the effect of each factor independently by removing the variation explained by the other factors. AMF colonization declined with increasing land use intensity (LUI) along with concurrent increases in non-AMF, suggesting that the ability of AMF to provide protection from pathogens declined under high LUI. In ALB and HAI mowing frequency and percent cover of additional P. lanceolata in the host plant neighborhood were important for AMF community composition. The similar proportional contribution of land use and host neighborhood to AMF community composition in a focal plant rhizosphere suggests that the diversity of this important group of soil microbes is similarly sensitive to changes at large and small scales.

Although temporal heterogeneity is a well-accepted driver of biodiversity, effects of interannual variation in land-use intensity (LUI) have not been addressed yet. Additionally, responses to land use can differ greatly among different organisms; therefore, overall effects of land-use on total local biodiversity are hardly known. To test for effects of LUI (quantified as the combined intensity of fertilization, grazing, and mowing) and interannual variation in LUI (SD in LUI across time), we introduce a unique measure of whole-ecosystem biodiversity, multidiversity. This synthesizes individual diversity measures across up to 49 taxonomic groups of plants, animals, fungi, and bacteria from 150 grasslands. Multidiversity declined with increasing LUI among grasslands, particularly for rarer species and aboveground organisms, whereas common species and belowground groups were less sensitive. However, a high level of interannual variation in LUI increased overall multidiversity at low LUI and was even more beneficial for rarer species because it slowed the rate at which the multidiversity of rare species declined with increasing LUI. In more intensively managed grasslands, the diversity of rarer species was, on average, 18% of the maximum diversity across all grasslands when LUI was static over time but increased to 31% of the maximum when LUI changed maximally over time. In addition to decreasing overall LUI, we suggest varying LUI across years as a complementary strategy to promote biodiversity conservation.

Plant traits have been widely used to characterize different aspects of the ecology of plant species. Despite its wide distribution and its proven significance at the level of individuals, communities and populations, the ability to form mycorrhizal associations has been largely neglected in these studies so far. Analyzing plant traits associated with the occurrence of mycorrhizas in plants can therefore enhance our understanding of plant strategies and distributions. Using a comparative approach, we tested for associations between mycorrhizal status and habitat characteristics, life-history traits and plant distribution patterns in 1752 species of the German flora (a major part of the Central European flora). Data were analyzed using log-linear models or generalized linear models, both accounting for phylogenetic relationships. Obligatorily mycorrhizal (OM) species tended to be positively associated with higher temperature, drier habitats, higher pH; and negatively with moist, acidic and fertile soils. Competitive species were more frequently OM and stress tolerators non-mycorrhizal (NM), while ruderal species did not show any preference. Facultatively mycorrhizal (FM) species showed the widest geographic and ecological amplitude. Indigenous species were more frequently FM and neophytes (recent aliens) more frequently OM than expected. FM species, differed markedly from OM and NM species in almost all analyzed traits. Specifically, they showed a wider geographic distribution and ecological niche. Our study of the relationships between mycorrhizal status and other plant traits provides a comprehensive test of existing hypotheses and reveals novel patterns. The clear distinction between FM and OM+NM species in terms of their ecology opens up a new field of research in plant-mycorrhizal ecology.

Understanding forces that structure plant communities is a key issue in plant community ecology. Traditionally, ecologists have focused on the absolute and the relative roles of competition and herbivory (Sih et al., 1985) and on the relative role of dispersal limitation vs biotic interactions (Huston, 1999), as well as on neutral models (Hubbell, 2001) and on their niche-based counterparts (Cadotte et al., 2008). Increasingly, mycorrhizal ecologists have argued that mycorrhizal fungi should also be considered as fundamentally important determinants of plant community composition. This conviction is motivated by a growing body of research which demonstrates that mycorrhizal fungi can have large effects on plant growth and may modify the strength of other interactions (van der Heijden, 2002), which is taken as proof that mycorrhizas should have a strong effect on plant community structure. We agree that the potential influence of mycorrhizal fungi on structuring plant communities has been conclusively shown. However, the realization of such potential under variable environmental conditions and complex biotic interactions, and the relative influence of the mycorrhizal symbiosis compared with other biotic and abiotic drivers, have only been addressed in a few studies (see Table 1) and remain uncertain for most systems. Interestingly, we find no studies where the relative influence of ectomycorrhizal or ericoid mycorrhizal fungi on plant community structure has been quantified. This may reflect the difficulty of measuring plant community outcomes (e.g. plant community diversity or evenness) in these symbioses, which tend to be formed by long-lived plants. Nonetheless, the widespread failure of ectomycorrhizal plants to establish in the absence of ectomycorrhizas suggests that the effect size of ectomycorrhizal fungi on plant community structure is likely to be large. Quantification, in this case, may only be possible through the creative utilization of individual-based

Residues of arbuscular mycorrhizal fungi (AMF) may be important for agroecosystem functioning due to their ability to promote soil aggregation, especially in coarse textured soils with little biomass input and low capacity to conserve soil organic matter (SOM). Our aim was to assess the fate of AMF residues with prolonged arable cropping in coarse textured soils in a subtropical savannah assuming that glomalin-related soil protein (GRSP), especially the MAb32B11-immunoreactive fraction, mainly constitutes material of AMF origin. In three agroecosystems on the South African Highveld, surface soils were sampled. The former grassland soils had a history of up to 98 yr of cropping. We measured four GRSP fractions: Bradford-reactive soil protein (BRSP) and immunoreactive soil protein (IRSP), and easily extractable fractions of both. The primary grassland sites exhibited generally low contents of SOM and low GRSP contents. Prolonged arable land use of former grassland soils reduced the content of GRSP further. The decline could be described with a mono-exponential function with rate constants ranging from 0.04 to 0.41 yr-1. Depending on the GRSP fraction, steady-state conditions were reached after 11-92 yr on a level of 39-69% of the initial contents. We conclude that even though GRSP fractions had the same hypothesized origin, they comprised pools with different stability or replacement rate. Easily extractable IRSP was lost most rapidly. In contrast to carbon, nitrogen and microbial residue dynamics, GRSP contents were not reduced below a certain steady-state level, despite potentially negative management effects on AMF, such as tillage, inclusion of fallows into crop rotation and fertilization with inorganic phosphorus. The steady-state GRSP contents coincided with low, but steady agroecosystem yields under the given cropping management.