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Despite substantial progress in understanding global biodiversity loss, major taxonomic and geographic knowledge gaps remain. Decision makers often rely on expert judgement to fill knowledge gaps, but are rarely able to engage with sufficiently large and diverse groups of specialists. To improve understanding of the perspectives of thousands of biodiversity experts worldwide, we conducted a survey and asked experts to focus on the taxa and freshwater, terrestrial, or marine ecosystem with which they are most familiar. We found several points of overwhelming consensus (for instance, multiple drivers of biodiversity loss interact synergistically) and important demographic and geographic differences in specialists’ perspectives and estimates. Experts from groups that are underrepresented in biodiversity science, including women and those from the Global South, recommended different priorities for conservation solutions, with less emphasis on acquiring new protected areas, and provided higher estimates of biodiversity loss and its impacts. This may in part be because they disproportionately study the most highly threatened taxa and habitats.

Ensuring stable food supplies is a major challenge for the 21st century. There is consensus that increased food production is necessary, but not sufficient, to achieve food security, and that agriculture should also aim at stabilizing crop production over time. In this context, biodiversity-based approaches to food security are increasingly being supported based on the fact that biodiversity can increase and stabilize crop production. However, agricultural systems are often highly fragmented and our current understanding of how such fragmentation affects biodiversity and food production remains incomplete, thus limiting our capacity to manage agricultural landscapes for food security. We developed a spatially explicit model of crop dynamics to investigate how the fragmentation of natural habitats for agricultural conversion impacts food production and food security, with a focus on animal-dependent crop production. Fragmentation produces a variety of spatial and biodiversity-mediated effects that affect both the mean and stability (temporal invariability) of animal-dependent crop production. Fragmentation has a dual effect on animal-dependent production. On the one hand, spatial aggregation of natural land decreases animal-dependent production by reducing the Landscape Pollination Potential, a metric that captures fragmentation and pollinator spillover effects within the agricultural landscape. But aggregation increases animal-dependent production by maintaining a higher pollinator diversity in larger fragments of natural habitat. The net effects of fragmentation on animal-dependent crop production depend on the land-use change pattern, the strength of the pollinator spillover to crop land and the animal pollination dependence of crops. Synthesis. Our study sheds new light in the food security debate by showing that high and stable crop production depends on biodiversity and the spatial fragmentation of agricultural landscapes, and by revealing the ecological mechan, Ensuring stable food supplies is a major challenge for the 21st century. There is consensus that increased food production is necessary, but not sufficient, to achieve food security, and that agriculture should also aim at stabilizing crop production over time. In this context, biodiversity-based approaches to food security are increasingly being supported based on the fact that biodiversity can increase and stabilize crop production. However, agricultural systems are often highly fragmented and our current understanding of how such fragmentation affects biodiversity and food production remains incomplete, thus limiting our capacity to manage agricultural landscapes for food security. We developed a spatially explicit model of crop dynamics to investigate how the fragmentation of natural habitats for agricultural conversion impacts food production and food security, with a focus on animal-dependent crop production. Fragmentation produces a variety of spatial and biodiversity-mediated effects that affect both the mean and stability (temporal invariability) of animal-dependent crop production. Fragmentation has a dual effect on animal-dependent production. On the one hand, spatial aggregation of natural land decreases animal-dependent production by reducing the Landscape Pollination Potential, a metric that captures fragmentation and pollinator spillover effects within the agricultural landscape. But aggregation increases animal-dependent production by maintaining a higher pollinator diversity in larger fragments of natural habitat. The net effects of fragmentation on animal-dependent crop production depend on the land-use change pattern, the strength of the pollinator spillover to crop land and the animal pollination dependence of crops. Synthesis. Our study sheds new light in the food security debate by showing that high and stable crop production depends on biodiversity and the spatial fragmentation of agricultural landscapes, and by revealing the ecological mechan

Ecological stability refers to a family of concepts used to describe how systems of interacting species vary through time and respond to disturbances. Because observed ecological stability depends on sampling scales and environmental context, it is notoriously difficult to compare measurements across sites and systems. Here, we apply stochastic dynamical systems theory to derive general statistical scaling relationships across time, space, and ecological level of organisation for three fundamental stability aspects: resilience, resistance, and invariance. These relationships can be calibrated using random or representative samples measured at individual scales, and projected to predict average stability at other scales across a wide range of contexts. Moreover deviations between observed vs. extrapolated scaling relationships can reveal information about unobserved heterogeneity across time, space, or species. We anticipate that these methods will be useful for cross‐study synthesis of stability data, extrapolating measurements to unobserved scales, and identifying underlying causes and consequences of heterogeneity.

Eutrophication is a widespread environmental change that usually reduces the stabilizing effect of plant diversity on productivity in local communities. Whether this effect is scale dependent remains to be elucidated. Here, we determine the relationship between plant diversity and temporal stability of productivity for 243 plant communities from 42 grasslands across the globe and quantify the effect of chronic fertilization on these relationships. Unfertilized local communities with more plant species exhibit greater asynchronous dynamics among species in response to natural environmental fluctuations, resulting in greater local stability (alpha stability). Moreover, neighborhood communities that have greater spatial variation in plant species composition within sites (higher beta diversity) have greater spatial asynchrony of productivity among communities, resulting in greater stability at the larger scale (gamma stability). Importantly, fertilization consistently weakens the contribution of plant diversity to both of these stabilizing mechanisms, thus diminishing the positive effect of biodiversity on stability at differing spatial scales. Our findings suggest that preserving grassland functional stability requires conservation of plant diversity within and among ecological communities.

Eutrophication is a widespread environmental change that usually reduces the stabilizing effect of plant diversity on productivity in local communities. Whether this effect is scale dependent remains to be elucidated. Here, we determine the relationship between plant diversity and temporal stability of productivity for 243 plant communities from 42 grasslands across the globe and quantify the effect of chronic fertilization on these relationships. Unfertilized local communities with more plant species exhibit greater asynchronous dynamics among species in response to natural environmental fluctuations, resulting in greater local stability (alpha stability). Moreover, neighborhood communities that have greater spatial variation in plant species composition within sites (higher beta diversity) have greater spatial asynchrony of productivity among communities, resulting in greater stability at the larger scale (gamma stability). Importantly, fertilization consistently weakens the contribution of plant diversity to both of these stabilizing mechanisms, thus diminishing the positive effect of biodiversity on stability at differing spatial scales. Our findings suggest that preserving grassland functional stability requires conservation of plant diversity within and among ecological communities.

Soil is one of the most biodiverse terrestrial habitats. Yet, we lack an integrative conceptual framework for understanding the patterns and mechanisms driving soil biodiversity. One of the underlying reasons for our poor understanding of soil biodiversity patterns relates to whether key biodiversity theories (historically developed for aboveground and aquatic organisms) are applicable to patterns of soil biodiversity. Here, we present a systematic literature review to investigate whether and how key biodiversity theories (species–energy relationship, theory of island biogeography, metacommunity theory, niche theory and neutral theory) can explain observed patterns of soil biodiversity. We then discuss two spatial compartments nested within soil at which biodiversity theories can be applied to acknowledge the scale‐dependent nature of soil biodiversity.

Soil organisms, including earthworms, are a key component of terrestrial ecosystems. However, little is known about their diversity, their distribution, and the threats affecting them. We compiled a global dataset of sampled earthworm communities from 6928 sites in 57 countries as a basis for predicting patterns in earthworm diversity, abundance, and biomass. We found that local species richness and abundance typically peaked at higher latitudes, displaying patterns opposite to those observed in aboveground organisms. However, high species dissimilarity across tropical locations may cause diversity across the entirety of the tropics to be higher than elsewhere. Climate variables were found to be more important in shaping earthworm communities than soil properties or habitat cover. These findings suggest that climate change may have serious implications for earthworm communities and for the functions they provide., Unión Europea. Horizonte 2020, Unión Europea. FP7, Ministerio de Ciencia e Innovación (MICCIN), sDiv [Synthesis Centre of the German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Academy of Finland, Natural Sciences and Engineering Research Council of Canada, DOB Ecology, TULIP Laboratory of Excellence, Russian Foundation for Basic Research, Tarbiat Modares University, Aurora Organic Dairy, UGC (NERO), Slovak Research and Development Agency, Science for Global Development through Wageningen University, Norman Borlaug LEAP Programme and International Atomic Energy Agency (IAEA), São Paulo Research Foundation (FAPESP), Oklahoma Agricultural Experiment Station, Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), Royal Canadian Geographical Society, Environmental Protection Agency (Ireland), University of Hawai‘i at Mānoa, U.S. Department of the Navy, Commander Pacific Fleet, Science and Engineering Research Board, Department of Science and Technology, New Delhi, India, Strategic Environmental Research and Development Program (SERDP) of the U.S. Department of Defense, Maranhão State Research Foundation (FAPEMA), Coordination for the Improvement of Higher Education Personnel (CAPES), Ministry of Education, Youth and Sports of the Czech Republic, Colorado Wheat Research Foundation; Zone Atelier Alpes, French National Research Agency, Austrian Science Fund, Landwirtschaftliche Rentenbank Frankfurt am Main, Welsh Government and the European Agricultural Fund for Rural Development, SÉPAQ, Ministry of Agriculture and Forestry of Finland, Science Foundation Ireland, University of Toronto (Faculty of Forestry), Haliburton Forest and Wildlife Reserve, NKU College of Arts and Sciences, Österreichische Forschungsförderungsgesellschaft, Mountain Agriculture Research Unit of the University of Innsbruck, Higher Education Commission of Pakistan, Kerala Forest Research Institute, Peechi, Kerala, UNEP/GEF/TSBF-CIAT, GRDC, AWI, LWRRDC, DRDC, National Scientific and Technical Research Council (CONICET), National Agency of Scientific and Technological Promotion (FONCyT), Universidad Nacional de Luján/FONCyT, Fonds de recherche sur la nature et les technologies du Québec, Deutsche Forschungsgemeinschaft, CONACYT, NSF, Institute for Environmental Science and Policy at the University of Illinois at Chicago, Dean’s Scholar Program at UIC, Garden Club of America Zone VI Fellowship in Urban Forestry from the Casey Tree Endowment Fund, J. E. Weaver Competitive Grant from the Nebraska Chapter of The Nature Conservancy, College of Liberal Arts and Sciences at DePaul University, Elmore Hadley Award for Research in Ecology and Evolution from the UIC Dept. of Biological Sciences, Comisión Interministerial de Ciencia y Tecnología (CICYT), Yokohama National University, MEXT KAKENHI, Japan Society for the Promotion of Science KAKENHI, ADEME, Syngenta Philippines, UPSTREAM, LTSER, Comisión Europea, National Science and Technology Base Resource Survey Project of China, McKnight Foundation, Program of Fundamental Researches of Presidium of Russian Academy of Sciences, Brazilian National Council of Research CNPq, French Ministry of Foreign and European Affairs, Depto. de Biodiversidad, Ecología y Evolución, Fac. de Ciencias Biológicas, TRUE, pub

1.Declines in global biodiversity have inspired a generation of studies that seek to characterise relationships between biodiversity and ecosystem functioning. The metrics for complementarity and selection effects derived by Loreau and Hector in 2001 remain some of the most influential and widely used statistics for studying these relationships. These metrics quantify the degree to which the effect of biodiversity on a given ecosystem function depends on only a few species that perform well in monoculture and in mixture (the selection effect) or if the effect of biodiversity on a given ecosystem function is independent of monoculture performance (the complementarity effect). This distinction may be useful in determining the consequences of the loss of rare vs. common or dominant species in natural systems. However, because these metrics require observations of all species in a community in monoculture, applications in natural systems have been limited.2.Here, we derive a statistical augmentation of the original partition, which can be applied to incomplete random samples of species drawn from a larger pool. This augmentation controls for the bias introduced by using only a subsample of species in monocultures rather than having monocultures of all species.3.Using simulated and empirical examples, we demonstrate the robustness of these metrics, and provide source code for calculating them. We find that these augmentations provide a reliable estimate of complementarity and selection effects as long as approximately 50% of the species present in mixture are present in monoculture and these species represent a random subset of the mixture.4.We foresee two primary applications for this method: (i) estimating complementarity and selection effects for experimentally assembled communities where monoculture data are lacking for some species, and (ii) extrapolating results from biodiversity experiments to diverse natural systems.

The effect of biodiversity on ecosystem functioning is one of the major questions of ecology. However, the role of phytoplankton functional diversity in ecosystem productivity and stability under fluctuating (i.e. non-equilibrium) environments remains largely unknown. Here we use a marine ecosystem model to study the effect of phytoplankton functional diversity on both ecosystem productivity and its stability for seasonally variable nutrient supply and temperature. Functional diversity ranges from low to high along these two environmental axes independently. Changes in diversity are obtained by varying the range of uptake strategies and thermal preferences of the species present in the community. Species can range from resource gleaners to opportunists, and from cold to warm thermal preferences. The phytoplankton communities self-assemble as a result of species selection by resource competition (nutrients) and environmental filtering (temperature). Both processes lead to species asynchrony but their effect on productivity and stability differ. We find that the diversity of temperature niches has a strong and direct positive effect on productivity and stability due to species complementarity, while the diversity of uptake strategies has a weak and indirect positive effect due to sampling probability. These results show that more functionally diverse phytoplankton communities lead to higher and more stable ecosystem productivity but the positive effect of biodiversity on ecosystem functioning depends critically on the type of environmental gradient.

Climate change mitigation initiatives based on biological sequestration of carbon have paid little attention to biodiversity, with important implications both for climate change mitigation and for ecosystem services that depend on biodiversity. Here the chapter reviews the theoretical and empirical evidence for forest biodiversity effects on carbon sequestration. This chapter suggests that protection of primary forests is the most effective option for maximizing carbon sequestration in forest ecosystems, and should be included in future international agreements. Because carbon sequestration is a long term goal, this chapter presents the case that avoidance of losses should be emphasized over short term uptake, and that maintenance of mixtures of dominant and subdominant species and genotypes are the safest option for carbon sequestration in plantations and agroforestry systems. Biodiversity conservation should be included in the development of policy for climate change mitigation initiatives based on carbon sequestration in forested systems, including those related to the Kyoto Protocol.

Conventional approaches to ecology often lack the necessary integration to make a compelling case for the critical importance of biodiversity to ecosystem functioning and human wellbeing. This linear approach does not prepare one for understanding and applying ecology in the context of the modern world. A different, rather unconventional approach is needed for understanding ecology and environmental biology, one that asks the question that is rarely asked — What is the significance of biodiversity to human wellbeing? That is what this book asks.

Meta-analysis of the first generation of biodiversity experiments has revealed that there is a general positive relationship between diversity and ecosystem processes that is consistent across trophic groups and ecosystem types. However, the mechanisms generating these general patterns are still under debate. While there are unresolved conceptual issues about the nature of diversity and complementarity, the debate is partly due to the difficulty of performing a full-factorial analysis of the functional effects of all species in a diverse community. However, there are now several different analytical approaches that can address mechanisms even when full factorial analysis is not possible. This chapter presents an overview and users' guide to these methods. This chapter concludes that the current toolbox of methods allows investigation of the mechanisms for most, if not all, biodiversity and ecosystem functioning experiments conducted to date that manipulate species within a single trophic level (e.g. plant biodiversity experiments). Methods that can address mechanisms in multitrophic studies are a key need for future research.

A large number of studies have now explicitly examined the relationship between species loss and ecosystem functions. The results from such “biodiversity experiments” have previously been collated and analyzed by two independent groups of authors. Both data sets show that reductions in species diversity generally result in reduced ecosystem functioning, even though the studies cover a wide range of ecosystems, diversity manipulations, and response variables. In this chapter, we analyze the two data sets in parallel to explain variation in the observed functional effects of biodiversity. The main conclusions are: 1) the functional effects of biodiversity differ among ecosystem types (but not between terrestrial and aquatic systems), 2) increases in species richness enhance community responses but negatively affect population responses, 3) stocks are more responsive than rates to biodiversity manipulations, 4) when diversity reductions at one trophic level affect a function at an adjacent trophic level (higher or lower), the function is often reduced 5) increased biodiversity results in increased invasion resistance. We also analyze the shape of the relationship between biodiversity and response variables, and discuss some consequences of different relationships.

The efficacy and practicability of an idea, and the will of individuals or society to explore it, determine whether it catalyzes change or merely enters the vast store of quiescent ideas that make up the bulk of humanity's collective wisdom. The idea that biodiversity influences ecosystem functioning is not new. As in all science, there remain differences among researchers on the interpretation of biodiversity and ecosystem functioning research, but the efficacy of the idea that the diversity of life, not just its mass, influences both the biogeochemical and biotic properties of ecosystems, is well established. This chapter looks across the many contributions in this book and considers a few messages the current field of biodiversity and ecosystem functioning research give us concerning efficacy, practicability, and societal will.

* A graduate level text which incorporates the latest developments in the field of biodiversity and ecosystem functioning, one of the most controversial and high profile areas of ecological research * The first volume to explore the economics of biodiversity and ecosystem services * Summarizes the eagerly anticipated findings of two large and highly respected scientific networks, BioMERGE and DIVERSITAS * Builds on the success and influence of the highly cited Biodiversity and Ecosystem Functioning (OUP, 2002) * The first volume advancing the scientific foundation of the United Nation's global environmental assessment, Millennium Ecosystem Assessment, that links human well-being with the conservation of biodiversity

Global change drivers are rapidly altering resource availability and biodiversity. While there is consensus that greater biodiversity increases the functioning of ecosystems, the extent to which biodiversity buffers ecosystem productivity in response to changes in resource availability remains unclear. We use data from 16 grassland experiments across North America and Europe that manipulated plant species richness and one of two essential resources—soil nutrients or water—to assess the direction and strength of the interaction between plant diversity and resource alteration on above-ground productivity and net biodiversity, complementarity, and selection effects. Despite strong increases in productivity with nutrient addition and decreases in productivity with drought, we found that resource alterations did not alter biodiversity–ecosystem functioning relationships. Our results suggest that these relationships are largely determined by increases in complementarity effects along plant species richness gradients. Although nutrient addition reduced complementarity effects at high diversity, this appears to be due to high biomass in monocultures under nutrient enrichment. Our results indicate that diversity and the complementarity of species are important regulators of grassland ecosystem productivity, regardless of changes in other drivers of ecosystem function.

Soil organic matter (SOM) is key to maintaining soil fertility, mitigating climate change, combatting land degradation, and conserving above- and below-ground biodiversity and associated soil processes and ecosystem services. In order to derive management options for maintaining these essential services provided by soils, policy makers depend on robust, predictive models identifying key drivers of SOM dynamics. Existing SOM models and suggested guidelines for future SOM modelling are defined mostly in terms of plant residue quality and input and microbial decomposition, overlooking the significant regulation provided by soil fauna. The fauna controls almost any aspect of organic matter turnover, foremost by regulating the activity and functional composition of soil microorganisms and their physical–chemical connectivity with soil organic matter. We demonstrate a very strong impact of soil animals on carbon turnover, increasing or decreasing it by several dozen percent, sometimes even turning C sinks into C sources or vice versa. This is demonstrated not only for earthworms and other larger invertebrates but also for smaller fauna such as Collembola. We suggest that inclusion of soil animal activities (plant residue consumption and bioturbation altering the formation, depth, hydraulic properties and physical heterogeneity of soils) can fundamentally affect the predictive outcome of SOM models. Understanding direct and indirect impacts of soil fauna on nutrient availability, carbon sequestration, greenhouse gas emissions and plant growth is key to the understanding of SOM dynamics in the context of global carbon cycling models. We argue that explicit consideration of soil fauna is essential to make realistic modelling predictions on SOM dynamics and to detect expected non-linear responses of SOM dynamics to global change. We present a decision framework, to be further developed through the activities of KEYSOM, a European COST Action, for when mechanistic SOM models i