Cameron Wagg

University of Zurich | UZH · Institut für Evolutionsbiologie und Umweltwissenschaften

One of the critical challenges in agriculture is enhancing yield without compromising its foundation, a healthy environment and, particularly, soils. Hence, there is an urgent need to identify management practices that simultaneously support soil health and production and help achieve environmentally sound production systems. To investigate how man...

Biodiversity loss and climate change have been determined as major global drivers affecting ecosystems and their functioning. In this context, drought was shown to have negative effects on ecosystems by disrupting ecological processes, which could be buffered in more biodiverse systems. Many studies, however, focus on effects on aboveground communi...

Conventional farming practices can lead to soil degradation and a decline in productivity. Regenerative agriculture (RA) is purported by advocates as a solution to these issues that focuses on soil health and carbon sequestration. The fundamental principles of RA are to keep the soil covered, minimise soil disturbance, preserve living roots in the...

Numerous studies have demonstrated that biodiversity drives ecosystem functioning, yet how biodiversity loss alters ecosystems functioning and stability in the long-term lacks experimental evidence. We report temporal effects of species richness on community productivity, stability, species asynchrony, and complementarity, and how the relationships...

Numerous studies have demonstrated that biodiversity drives ecosystem functioning, yet there is a lack of knowledge about how biodiversity loss alters ecosystems functioning and stability in the long-term. We report on temporal changes in the species richness–productivity, –stability, –species asynchrony, and –complementarity relationships over 17...

Soil fungi are fundamental to plant productivity, yet their influence on the temporal stability of global terrestrial ecosystems, and their capacity to buffer plant productivity against extreme drought events, remain uncertain. Here we combined three independent global field surveys of soil fungi with a satellite-derived temporal assessment of plan...

Growing threats from extreme climatic events and biodiversity loss have raised concerns about their interactive consequences for ecosystem functioning. Evidence suggests biodiversity can buffer ecosystem functioning during such climatic events. However, whether exposure to extreme climatic events will strengthen the biodiversity-dependent buffering...

Background and aims Plant community stability is threatened by anthropogenic climate changes such as increased precipitation. Arbuscular mycorrhizal (AM) fungi have been shown to drive the resistance of ecosystems against climate changes to provide stable ecosystem functions. However, how AMF affects plant community stability under climate change i...

It is well established that grassland degradation negatively affects ecosystem functioning. Many studies have explored the changes of individual functions involved with grassland degradation, while fewer considered an ecosystem multifunctionality (EMF) summarizing the multiple simultaneous changes in the response of ecosystem functions to grassland...

Non-marketable crops are increasingly being used as a tool to promote agroecosystem services and sustainable agriculture. Nevertheless, crops vary greatly in the traits by which they capture resources and influence the local ecosystem. Here we report on the traits and associated soil microbial communities that relate to aboveground biomass producti...

Experiments showed that biodiversity increases grassland productivity and nutrient exploitation, potentially reducing fertiliser needs. Enhancing biodiversity could improve P-use efficiency of grasslands, which is beneficial given that rock-derived P fertilisers are expected to become scarce in the future. Here, we show in a biodiversity experiment...

Plant and soil microbial diversities are linked through a range of interactions, including the exchange of carbon and nutrients but also herbivory and pathogenic effects. Over time, associations between plant communities and their soil microbiota may strengthen and become more specific, resulting in stronger associations between plant and soil micr...

Growing threats from extreme climatic events and biodiversity loss have raised concerns about their interactive consequences for ecosystem functioning. Evidence suggests that biodiversity is crucial to buffer ecosystem functioning facing climatic extremes. However, whether evolutionary processes in species mixtures underpin such biodiversity-depend...

Theoretical and empirical advances have revealed the importance of biodiversity for stabilizing ecosystem functions through time. Despite the global degradation of soils, whether the loss of soil microbial diversity can destabilize ecosystem functioning is poorly understood. Here, we experimentally quantified the contribution of soil fungal and bac...

Canopy structure is an important driver of the energy budget of grassland ecosystem and is, at the same time, altered by plant diversity. Diverse plant communities typically have taller and more densely packed canopies than less diverse communities. With this, they absorb more radiation, have a higher transpiring leaf surface and are better coupled...

In natural ecosystems, positive effects of plant diversity on ecosystem functioning have been widely observed, yet whether this is true in cropping systems remains unclear. Here we assessed the impact of crop diversification on soil microbial diversity, soil multifunctionality (SMF) and crop yields in 155 cereal fields across a 3,000 km north–south...

Plant and soil microbial diversity are linked through a range of interactions, including the exchange of carbon and nutrients but also herbivory and pathogenic effects. Over time, associations between plant communities and their soil microbiota may strengthen and become more specific, resulting in stronger associations between plant and soil microb...

Nutrient enrichment can reduce ecosystem stability, typically measured as temporal stability of a single function, e.g. plant productivity. Moreover, nutrient enrichment can alter plant‐soil interactions (e.g. mycorrhizal symbiosis) that determine plant community composition and productivity. Thus, it is likely that nutrient enrichment and interact...

Plant diversity is an important driver of below‐ground ecosystem functions, such as root growth, soil organic matter (SOM) storage and microbial metabolism, mainly by influencing the interactions between plant roots and soil. Dissolved organic matter (DOM), as the most mobile form of SOM, plays a crucial role for a multitude of soil processes that...

A large body of research shows that biodiversity loss can reduce ecosystem functioning. However, much of the evidence for this relationship is drawn from biodiversity–ecosystem functioning experiments in which biodiversity loss is simulated by randomly assembling communities of varying species diversity, and ecosystem functions are measured. This r...

Theoretical and empirical advances have revealed the importance of biodiversity for stabilizing ecosystem functions through time. Yet despite the global degradation of soils, how the loss of soil microbial diversity can de-stabilizes ecosystem functioning is unknown. Here we experimentally quantified the contribution diversity and the temporal dyna...

Understanding factors that maintain ecosystem stability is critical in the face of environmental change. Experiments simulating species loss from grassland have shown that losing biodiversity decreases ecosystem stability. However, as the originally sown experimental communities with reduced biodiversity develop, plant evolutionary processes or the...

Aims Intensive land management practices can compromise soil biodiversity, thus jeopardizing long-term soil productivity. Arbuscular mycorrhizal fungi (AMF) play a pivotal role in promoting soil productivity through obligate symbiotic associations with plants. However, it is not clear how properties of plant communities, especially species richness...

Arbuscular mycorrhizal fungi (AMF) play an important role in maintaining plant diversity and productivity in grassland ecosystems. However, very few studies have investigated how AMF and plant communities co‐vary between contrasting environments in natural ecosystems. Intensive sampling (50 soil samples) was conducted in natural open grasslands at...

The structure of a plant community in terms of functional traits can strongly affect community productivity. Two components may contribute to this, community-wide trait means (mass-ratio hypothesis) or community-wide trait variations (diversity hypothesis) across species and individuals. We compared the explanatory power of the two hypotheses for e...

Video abstract: https://youtu.be/HhyGXkz6QGY Knowledge from agriculture and ecological field studies suggests that plant monocultures lose productivity over time, but the drivers underlying the long‐term performance of monocultures of grassland species are not completely understood. We examined the performance of 60 grassland species growing in m...

Plant diversity loss can alter plant–plant and plant–rhizosphere microbiome interactions. These altered interactions, in turn, may exert diversity‐driven selection pressure to which plants respond with phenotypic changes. Diverse plant communities may favour the survival and fitness of individuals with traits that avoid competition. Conversely, mon...

Models of natural processes necessarily sacrifice some realism for the sake of tractability. Detailed, parameter‐rich models often provide accurate estimates of system behaviour but can be data‐hungry and difficult to operationalize. Moreover, complexity increases the danger of ‘over‐fitting’, which leads to poor performance when models are applied...

1. The inference of pairwise competitive outcomes (PCO) and multispecies competitive ranks and intransitivity from empirical data is essential to evaluate how competition shapes plant communities. Three categories of methods, differing in theoretical background and data requirements, have been used: (a) theoretically sound coexistence theory-based...

The soil microbiome is highly diverse and comprises up to one quarter of Earth’s diversity. Yet, how such a diverse and functionally complex microbiome influences ecosystem functioning remains unclear. Here we manipulated the soil microbiome in experimental grassland ecosystems and observed that microbiome diversity and microbial network complexity...

Experiments simulating species loss from grassland ecosystems have shown that losing biodiversity decreases the ability of ecosystems to buffer disturbances. However, plant or plant-soil evolutionary processes may allow ecosystems to regain stability and resilience over time. We explored such effects in a long-term grassland biodiversity experiment...

Biodiversity often enhances ecosystem functioning likely due to multiple, often temporarily separated drivers. Yet, most studies are based on one or two snapshot measurements per year. We estimated productivity using bi-weekly estimates of high-resolution canopy height in 2 years with terrestrial laser scanning (TLS) in a grassland diversity experi...

A large body of research shows that biodiversity loss can reduce ecosystem functioning, thus providing support for the conservation of biological diversity. Much of the evidence for this relationship is drawn from biodiversity-ecosystem functioning experiments (hereafter: biodiversity experiments), in which biodiversity loss is simulated by randoml...

Droughts associated with climate change alter ecosystem functions, especially in systems characterized by low biodiversity, such as agricultural fields. Management strategies aimed at buffering climate change effects include the enhancement of intraspecific crop diversity as well as the diversity of beneficial interactions with soil biota, such as...

A recent paper by Pillai and Gouhier (2019) (PG) in Ecology argues that biodiversity–ecosystem functioning (BEF) effects calculated by the additive partitioning approach introduced by Loreau and Hector (2001) (LH) are flawed and overestimate biodiversity effects. Biodiversity effects are based on the null expectation that the addition of more speci...

Although diversity‐dependent plant–soil feedbacks (PSFs) may contribute significantly to plant diversity effects on ecosystem functioning, the influences of underlying abiotic and biotic mechanistic pathways have been little explored to date. Here, we assessed such pathways with a PSF experiment using soil conditioned for ≥12 yr from two grassland...

Species‐rich plant communities can induce unique soil biotic legacy effects through changing the abundance and composition of soil biota. These soil legacy effects can cause feedbacks to influence plant performance. In addition, soil biota can induce (defensive) secondary metabolites in shoots and roots and thus affect plant–herbivore interactions....

One of the unifying goals of ecology is understanding the mechanisms that drive ecological patterns. For any particular observed pattern, ecologists have proposed varied mechanistic models. However, in spite of their differences, all of these mechanistic models rely on either abiotic conditions or biotic conditions, our “ecological first principles...

Concern about the functional consequences of unprecedented loss in biodiversity has prompted biodiversity-ecosystem functioning (BEF) research to become one of the most active fields of ecological research in the past 25 years. Hundreds of experiments have manipulated biodiversity as an independent variable and found compelling support that the fun...

One of the unifying goals of ecology is understanding the mechanisms that drive ecological patterns. For any particular observed pattern, ecologists have proposed varied mechanistic models. However, in spite of their differences, all of these mechanistic models rely on either abiotic conditions or biotic conditions, our “ecological first principles...

Soil microbes are known to be key drivers of a number of essential ecosystem processes such as nutrient cycling, plant productivity and the maintenance of plant species diversity. However, how plant species diversity and identity affect soil microbial diversity and community composition in the rhizosphere is largely unknown. We tested whether, over...

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 context-dependency of mycor...

Soil microbial communities affect species demographic rates of plants. In turn, plants influence the composition and function of the soil microbiome, potentially resulting in beneficial feedbacks that alter their fitness and establishment. For example, differences in the ability to stimulate soil enzyme activity among plant lineages may affect plan...

High biodiversity aboveground tends to increase the stability of ecosystem functioning when faced with a changing environment. However, whether and how soil biota affect ecosystem stability is less clear. Here, we introduce a framework for understanding the effects of soil biota on variation in ecosystem functioning under environmental changes. We...

Although diversity-dependent plant-soil feedbacks (PSFs) may contribute significantly to plant diversity effects on ecosystem functioning, the influence of underlying abiotic and biotic mechanistic pathways have been little explored to date. Here, we assessed such pathways with a PSF experiment using soil conditioned for ≥12 years from two grasslan...

The widely observed positive relationship between plant diversity and ecosystem functioning is thought to be substantially driven by complementary resource use of plant species. Recent work suggests that biotic interactions among plants and between plants and soil organisms drive key aspects of resource use complementarity. Here we provide a concep...

The extent to which plants can reduce nutrient concentrations in soil and thereby compete with others may increase with nutrient mobility. Hyphae of arbuscular mycorrhizal fungi ( AMF ) can extend the soil volume from which plants acquire phosphorus (P), thus increasing competition for these resources with neighbours. In this study, we tested wheth...

Soil microbes are known to be involved in a number of essential ecosystem processes such as nutrient cycling, plant productivity and the maintenance of plant species diversity. However, how plant species diversity and identity affect soil microbial diversity and community composition is largely unknown. We tested whether, over the course of 11 year...

It is becoming well‐established that plant diversity is instrumental in stabilizing the temporal functioning of ecosystems through population dynamics and the so‐called insurance or portfolio effect. However, it remains unclear whether diversity–stability relationships and the role of population dynamics in soil microbial communities parallel those...

Co-evolution between plants and arbuscular mycorrhizal fungi (AMF) may occur over short time spans. However, whether plants and AMF co-adapt and how this may be influenced by plant diversity has never been addressed. We carried out a plant-AMF experiment using five plant species and AMF selected over 11 years in plant monocultures or mixtures. Sing...

The extensive use of traits in ecological studies over the last few decades to predict community functions has revealed that plant traits are plastic and respond to various environmental factors. These plant traits are assumed to predict how plants compete and capture resources. Variation in stoichiometric ratios both within and across species refl...

(Access to full-text: http://rdcu.be/v035) Plant diversity influences many ecosystem functions including root decomposition. However, due to the presence of multiple pathways via which plant diversity may affect root decomposition, our mechanistic understanding of their relationships is limited. In a grassland biodiversity experiment, we simultaneo...

Species extinctions from local communities negatively affect ecosystem functioning. Ecological mechanisms underlying these impacts are well studied, but the role of evolutionary processes is rarely assessed. Using a long-term field experiment, we tested whether natural selection in plant communities increased biodiversity effects on productivity. W...

Species extinctions from local communities can negatively affect ecosystem functioning. Ecological mechanisms underlying these impacts are well studied but the role of evolutionary processes is rarely assessed. Using a long-term field experiment, we tested whether natural selection in plant communities increased the effects of biodiversity on produ...

Increasing frequency of extreme climatic events can disrupt ecosystem processes and destabilize ecosystem functioning. Biodiversity may dampen these negative effects of environmental perturbations to provide greater ecosystem stability. We assessed the effects of plant diversity on the resistance, recovery and stability of experimental grassland ec...

Plants influence associated soil biotic communities that in turn can alter the performance of the subsequently growing plants. Although such “plant–soil feedbacks” ( PSF s) are considered as important drivers of plant community assembly, past PSF studies have mainly addressed plant biomass production. However, plant performance is not only the prod...

Niche complementarity and competitive disparity are driving mechanisms behind plant community assembly and productivity. Consequently, there is great interest in predicting species complementarity and their competitive differences from their functional traits as dissimilar species may compete less and result in more complete use of resources. Here...

Research on the functional importance of biodiversity, motivated by global species loss, has documented that plant species richness affects many plant-related ecosystem functions. Less is known about the effects of plant species richness on functions related to higher trophic levels, such as the consumption of biomass by animals, that is, herbivory...

In the past two decades, a large number of studies have investigated the relationship between biodiversity and ecosystem functioning, most of which focussed on a limited set of ecosystem variables. The Jena Experiment was set up in 2002 to investigate the effects of plant diversity on element cycling and trophic interactions, using a multi-discipli...

2017. Pitfall trap sampling bias depends on body mass, temperature, and trap number: insights from an individual-based model. Ecosphere 8(4): Abstract. The diversity and community composition of ground arthropods is routinely analyzed by pitfall trap sampling, which is a cost-and time-effective method to gather large numbers of replicates but also...

Climate change is projected to increase the frequency of extreme events, such as flooding and droughts, which are anticipated to have negative effects on the biodiversity of primary producers and consequently the associated consumer communities. Here we assessed the effects of an extreme early summer flooding event in 2013 on ant colonies along an...

Recently, we proposed that soil ecological engineering can be used to enhance agricultural sustainability [1]. In their response to our article, Machado et al. [2] stress the point that potential undesirable side effects of soil ecological manipulations have to be considered and carefully investigated. We fully agree with their general appeal to co...

Aims Climate warming raises the probability of range expansions of warm-adapted temperate species into areas currently dominated by cold-adapted boreal species. Warming-induced plant range expansions could partly depend on how warming modifies relationships with soil biota that promote plant growth, such as by mineralizing nutrients. Here, we grew...

Climate change is expected to increase the frequency and magnitude of extreme weather events. It is therefore of major importance to identify the community attributes that confer stability in ecological communities during such events. In June 2013, a flood event affected a plant diversity experiment in Central Europe (Jena, Germany). We assessed th...

Soil organisms are an integral component of ecosystems, but their activities receive little recognition in agricultural management strategies. Here we synthesize the potential of soil organisms to enhance ecosystem service delivery and demonstrate that soil biodiversity promotes multiple ecosystem functions simultaneously (i.e., ecosystem multifunc...