The iDiv Ecotron - a flexible research platform for multitrophic biodiversity research

Across the globe, ecological communities are confronted with multiple global environmental change drivers, and they are responding in complex ways ranging from behavioural, physiological, and morphological changes within populations to changes in community composition and food web structure with consequences for ecosystem functioning. A better understanding of global change-induced alterations of multitrophic biodiversity and the ecosystem-level responses in terrestrial ecosystems requires holistic and integrative experimental approaches to manipulate and study complex communities and processes above and below the ground. We argue that mesocosm experiments fill a critical gap in this context, especially when based on ecological theory and coupled with microcosm experiments, field experiments, and observational studies of macroecological patterns. We describe the design and specifications of a novel terrestrial mesocosm facility, the iDiv Ecotron. It was developed to allow the setup and maintenance of complex communities and the manipulation of several abiotic factors in a near-natural way, while simultaneously measuring multiple ecosystem functions. To demonstrate the capabilities of the facility, we provide a case study. This study shows that changes in aboveground multitrophic interactions caused by decreased predator densities can have cascading effects on the composition of belowground communities. The iDiv Ecotrons technical features, which allow for the assembly of an endless spectrum of ecosystem components, create the opportunity for collaboration among researchers with an equally broad spectrum of expertise. In the last part, we outline some of such components that will be implemented in future ecological experiments to be realized in the iDiv Ecotron. Key words: food webs, biodiversity and ecosystem functioning, mesocosms, biotic interactions, lysimeters, climate chambers

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Food web structure alters ecological communities top-heaviness with little effect on the biodiversity-functioning relationship

10.1101/2020.06.10.144949 ◽

2020 ◽

Author(s):

Eva Delmas ◽

Daniel B. Stouffer ◽

Timothée Poisot

Keyword(s):

Food Web ◽

Food Chain ◽

Ecosystem Functioning ◽

Ecosystem Processes ◽

Ecosystem Dynamics ◽

Ecosystem Functions ◽

Ecological Communities ◽

Bioenergetic Model ◽

Food Web Structure ◽

Web Structure

In a rapidly changing world, the composition, diversity and structure of ecological communities face many threats. Biodiversity-Ecosystem Functioning (BEF) and community food-chain analyses have focused on investigating the consequences of these changes on ecosystem processes and the resulting functions. These different and diverging conceptual frameworks have each produced important results and identified a set of important mechanisms, that shape ecosystem functions. But the disconnection between these frameworks, and the various simplifications of the study systems are not representative of the complexity of real-world communities. Here we use food webs as a more realistic depiction of communities, and use a bioenergetic model to simulate their biomass dynamics and quantify the resulting flows and stocks of biomass. We use tools from food web analysis to investigate how the predictions from BEF and food-chain analyses fit together, how they correlate to food-web structure and how it might help us understand the interplay between various drivers of ecosystem functioning. We show that food web structure is correlated to the community’s efficiency in storing the captured biomass, which may explain the distribution of biomass (top heaviness) across the different trophic compartments (producers, primary and secondary consumers). While we know that ecological network structure is important in shaping ecosystem dynamics, identifying structural attributes important in shaping ecosystem processes and synthesizing how it affects various underpinning mechanisms may help prioritize key conservation targets to protect not only biodiversity but also its structure and the resulting services.

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Microbial Community Resilience across Ecosystems and Multiple Disturbances

Microbiology and Molecular Biology Reviews ◽

10.1128/mmbr.00026-20 ◽

2021 ◽

Vol 85 (2) ◽

Author(s):

Laurent Philippot ◽

Bryan S. Griffiths ◽

Silke Langenheder

Keyword(s):

Microbial Community ◽

Global Environmental Change ◽

Terrestrial Ecosystems ◽

Ecosystem Functions ◽

Community Stability ◽

Multiple Disturbances ◽

Rates Of Change ◽

Complex Processes ◽

Global Environmental ◽

Nonadditive Effects

SUMMARY The ability of ecosystems to withstand disturbances and maintain their functions is being increasingly tested as rates of change intensify due to climate change and other human activities. Microorganisms are crucial players underpinning ecosystem functions, and the recovery of microbial communities from disturbances is therefore a key part of the complex processes determining the fate of ecosystem functioning. However, despite global environmental change consisting of numerous pressures, it is unclear and controversial how multiple disturbances affect microbial community stability and what consequences this has for ecosystem functions. This is particularly the case for those multiple or compounded disturbances that occur more frequently than the normal recovery time. The aim of this review is to provide an overview of the mechanisms that can govern the responses of microbes to multiple disturbances across aquatic and terrestrial ecosystems. We first summarize and discuss properties and mechanisms that influence resilience in aquatic and soil biomes to determine whether there are generally applicable principles. Following, we focus on interactions resulting from inherent characteristics of compounded disturbances, such as the nature of the disturbance, timing, and chronology that can lead to complex and nonadditive effects that are modulating the response of microorganisms.

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Warming decreases host survival with multiple parasitoids, but parasitoid performance also decreases

10.1101/2021.08.24.457463 ◽

2021 ◽

Author(s):

Mélanie Thierry ◽

Nicholas A. Pardikes ◽

Benjamin Rosenbaum ◽

Miguel G. Ximénez-Embún ◽

Jan Hrček

Keyword(s):

Ecosystem Functioning ◽

Species Interactions ◽

Community Dynamics ◽

Abiotic Factors ◽

Interactive Effects ◽

Global Changes ◽

Ecological Communities ◽

Top Down ◽

Multiple Predators ◽

Abiotic And Biotic Factors

AbstractCurrent global changes are reshaping ecological communities and modifying environmental conditions. We need to recognize the combined impact of these biotic and abiotic factors on species interactions, community dynamics and ecosystem functioning. Specifically, the strength of predator-prey interactions often depends on the presence of other natural enemies: it weakens with competition and interference, or strengthens with facilitation. Such effects of multiple predators on prey are likely to be affected by changes in the abiotic environment, altering top-down control, a key structuring force in both natural and agricultural ecosystems. Here, we investigated how warming alters the effects of multiple predators on prey suppression using a dynamic model coupled with empirical laboratory experiments with Drosophila-parasitoid communities. While the effects of multiple parasitoids on host suppression were the average of the effects of individual parasitoid at ambient temperature, host suppression with multiple parasitoids was higher than expected under warming. Multiple parasitoid species had equivalent effect to multiple individuals of a same species. While multiple parasitoids enhanced top-down control under warming, parasitoid performance generally declined when another parasitoid was present due to competitive interactions, which could reduce top-down control in the long-term. Our study highlights the importance of accounting for interactive effects between abiotic and biotic factors to better predict community dynamics in a rapidly changing world, and better preserve ecosystem functioning and services such as biological control.

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Novel ecosystems

10.1093/oso/9780198808978.003.0007 ◽

2017 ◽

Cited By ~ 2

Author(s):

Richard J. Hobbs

Keyword(s):

Review Process ◽

Ecosystem Functions ◽

Novel Ecosystems ◽

Conservation Value ◽

Ecological Communities ◽

Hard Time

This chapter relates the story of the development of recent ideas relating to ecosystems that are greatly modified by environmental and biological changes. Originally such ecosystems were given attention simply because they were an understudied set of systems that could teach us about how ecological communities assemble and reassemble. However, as the widespread prevalence of such “novel ecosystems” became obvious, some data suggested they could deliver important ecosystem functions. This led to a debate regarding the values, management, and restoration of altered ecosystems. The original papers had a hard time in the review process, and debate has, at times, been rancorous. However, many practitioners and ecologists now find the concept of novel ecosystems useful, and the possibility of their conservation value worth investigating.

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Potassium Control of Plant Functions: Ecological and Agricultural Implications

Plants ◽

10.3390/plants10020419 ◽

2021 ◽

Vol 10 (2) ◽

pp. 419

Author(s):

Jordi Sardans ◽

Josep Peñuelas

Keyword(s):

Food Security ◽

Stress Responses ◽

Crop Production ◽

Terrestrial Ecosystem ◽

Terrestrial Ecosystems ◽

Wood Formation ◽

Cellular Growth ◽

Ecosystem Functions ◽

Metabolite Transport ◽

Physiological Functions

Potassium, mostly as a cation (K+), together with calcium (Ca2+) are the most abundant inorganic chemicals in plant cellular media, but they are rarely discussed. K+ is not a component of molecular or macromolecular plant structures, thus it is more difficult to link it to concrete metabolic pathways than nitrogen or phosphorus. Over the last two decades, many studies have reported on the role of K+ in several physiological functions, including controlling cellular growth and wood formation, xylem–phloem water content and movement, nutrient and metabolite transport, and stress responses. In this paper, we present an overview of contemporary findings associating K+ with various plant functions, emphasizing plant-mediated responses to environmental abiotic and biotic shifts and stresses by controlling transmembrane potentials and water, nutrient, and metabolite transport. These essential roles of K+ account for its high concentrations in the most active plant organs, such as leaves, and are consistent with the increasing number of ecological and agricultural studies that report K+ as a key element in the function and structure of terrestrial ecosystems, crop production, and global food security. We synthesized these roles from an integrated perspective, considering the metabolic and physiological functions of individual plants and their complex roles in terrestrial ecosystem functions and food security within the current context of ongoing global change. Thus, we provide a bridge between studies of K+ at the plant and ecological levels to ultimately claim that K+ should be considered at least at a level similar to N and P in terrestrial ecological studies.

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Identifying appropriate sampling and modelling approaches for analysing distributional patterns of Antarctic terrestrial arthropods along the Victoria Land latitudinal gradient

Antarctic Science ◽

10.1017/s095410201000043x ◽

2010 ◽

Vol 22 (6) ◽

pp. 742-748 ◽

Cited By ~ 4

Author(s):

Tancredi Caruso ◽

Ian D. Hogg ◽

Roberto Bargagli

Keyword(s):

Abiotic Factors ◽

Relevant Literature ◽

Biotic Interactions ◽

Terrestrial Ecosystems ◽

Climatic Conditions ◽

Trophic Levels ◽

Terrestrial Arthropods ◽

Victoria Land ◽

Dispersal Capability ◽

Modelling Techniques

AbstractBiotic communities in Antarctic terrestrial ecosystems are relatively simple and often lack higher trophic levels (e.g. predators); thus, it is often assumed that species’ distributions are mainly affected by abiotic factors such as climatic conditions, which change with increasing latitude, altitude and/or distance from the coast. However, it is becoming increasingly apparent that factors other than geographical gradients affect the distribution of organisms with low dispersal capability such as the terrestrial arthropods. In Victoria Land (East Antarctica) the distribution of springtail (Collembola) and mite (Acari) species vary at scales that range from a few square centimetres to regional and continental. Different species show different scales of variation that relate to factors such as local geological and glaciological history, and biotic interactions, but only weakly with latitudinal/altitudinal gradients. Here, we review the relevant literature and outline more appropriate sampling designs as well as suitable modelling techniques (e.g. linear mixed models and eigenvector mapping), that will more adequately address and identify the range of factors responsible for the distribution of terrestrial arthropods in Antarctica.

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Impact of grazing intensity on seasonal variations in soil organic carbon and soil CO 2 efflux in two semiarid grasslands in southern Botswana

Philosophical Transactions of the Royal Society B Biological Sciences ◽

10.1098/rstb.2012.0102 ◽

2012 ◽

Vol 367 (1606) ◽

pp. 3076-3086 ◽

Cited By ~ 53

Author(s):

Andrew D. Thomas

Keyword(s):

Organic Carbon ◽

Soil Organic Carbon ◽

Seasonal Variations ◽

Field Experiments ◽

Grazing Intensity ◽

C Sequestration ◽

Ecosystem Functions ◽

Semiarid Environments ◽

The Impact ◽

And Storage

Biological soil crusts (BSCs) are an important source of organic carbon, and affect a range of ecosystem functions in arid and semiarid environments. Yet the impact of grazing disturbance on crust properties and soil CO 2 efflux remain poorly studied, particularly in African ecosystems. The effects of burial under wind-blown sand, disaggregation and removal of BSCs on seasonal variations in soil CO 2 efflux, soil organic carbon, chlorophyll a and scytonemin were investigated at two sites in the Kalahari of southern Botswana. Field experiments were employed to isolate CO 2 efflux originating from BSCs in order to estimate the C exchange within the crust. Organic carbon was not evenly distributed through the soil profile but concentrated in the BSC. Soil CO 2 efflux was higher in Kalahari Sand than in calcrete soils, but rates varied significantly with seasonal changes in moisture and temperature. BSCs at both sites were a small net sink of C to the soil. Soil CO 2 efflux was significantly higher in sand soils where the BSC was removed, and on calcrete where the BSC was buried under sand. The BSC removal and burial under sand also significantly reduced chlorophyll a , organic carbon and scytonemin . Disaggregation of the soil crust, however, led to increases in chlorophyll a and organic carbon. The data confirm the importance of BSCs for C cycling in drylands and indicate intensive grazing, which destroys BSCs through trampling and burial, will adversely affect C sequestration and storage. Managed grazing, where soil surfaces are only lightly disturbed, would help maintain a positive carbon balance in African drylands.

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Plant traits are poor predictors of long-term ecosystem functioning

10.1101/859314 ◽

2019 ◽

Author(s):

Fons van der Plas ◽

Thomas Schröder-Georgi ◽

Alexandra Weigelt ◽

Kathryn Barry ◽

Sebastian Meyer ◽

...

Keyword(s):

Plant Species ◽

Ecosystem Functioning ◽

Plant Traits ◽

Vascular Plant ◽

Plant Performance ◽

Ecosystem Functions ◽

Average Percentage ◽

Functional Consequences ◽

Small Set

ABSTRACTEarth is home to over 350,000 vascular plant species1 that differ in their traits in innumerable ways. Yet, a handful of functional traits can help explaining major differences among species in photosynthetic rate, growth rate, reproductive output and other aspects of plant performance2–6. A key challenge, coined “the Holy Grail” in ecology, is to upscale this understanding in order to predict how natural or anthropogenically driven changes in the identity and diversity of co-occurring plant species drive the functioning of ecosystems7, 8. Here, we analyze the extent to which 42 different ecosystem functions can be predicted by 41 plant traits in 78 experimentally manipulated grassland plots over 10 years. Despite the unprecedented number of traits analyzed, the average percentage of variation in ecosystem functioning that they jointly explained was only moderate (32.6%) within individual years, and even much lower (12.7%) across years. Most other studies linking ecosystem functioning to plant traits analyzed no more than six traits, and when including either only six random or the six most frequently studied traits in our analysis, the average percentage of explained variation in across-year ecosystem functioning dropped to 4.8%. Furthermore, different ecosystem functions were driven by different traits, with on average only 12.2% overlap in significant predictors. Thus, we did not find evidence for the existence of a small set of key traits able to explain variation in multiple ecosystem functions across years. Our results therefore suggest that there are strong limits in the extent to which we can predict the long-term functional consequences of the ongoing, rapid changes in the composition and diversity of plant communities that humanity is currently facing.

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Mesoscale variations in the assemblage structure and trophodynamics of mesozooplankton communities of the Adriatic basin (Mediterranean Sea)

10.5194/bg-2021-240 ◽

2021 ◽

Author(s):

Emanuela Fanelli ◽

Samuele Menicucci ◽

Sara Malavolti ◽

Andrea De Felice ◽

Iole Leonori

Keyword(s):

Food Web ◽

Food Webs ◽

Mediterranean Sea ◽

Environmental Variables ◽

Complex Structure ◽

Assemblage Structure ◽

Trophic Levels ◽

Ecosystem Functions ◽

Food Web Structure ◽

Adriatic Basin

Abstract. Zooplankton are critical to the functioning of ocean food webs because of their utter abundance and vital ecosystem roles. Zooplankton communities are highly diverse and thus perform a variety of ecosystem functions, thus changes in their community or food web structure may provide evidence of ecosystem alteration. Assemblage structure and trophodynamics of mesozooplantkon communities were examined across the Adriatic basin, the northernmost and most productive basin of the Mediterranean Sea. Samples were collected in June–July 2019 along coast-offshore transects covering the whole western Adriatic side, consistently environmental variables were also recorded. Results showed a clear separation between samples from the northern-central Adriatic and the southern ones, with a further segregation, although less clear, of inshore vs. off-shore stations, the latter mostly dominated in the central and southern stations by gelatinous plankton. Such patterns were mainly driven by chlorophyll-a concentration (as a proxy of primary production) for northern-central stations, i.e. closer to the Po river input, and by temperature and salinity, for southern ones, with the DistLM model explaining 46 % of total variance. The analysis of stable isotopes of nitrogen and carbon allowed to identify a complex food web characterized by 3 trophic levels from herbivores to carnivores, passing through the mixed feeding behavior of omnivores, shifting from phytoplankton/detritus ingestion to microzooplankton. Trophic structure also spatially varied according to sub-area, with the northern-central sub-areas differing from each other and from the southern stations. Our results highlighted the importance of environmental variables as drivers of zooplanktonic communities and the complex structure of their food webs. Disentangling and considering such complexity is crucial to generate realistic predictions on the functioning of aquatic ecosystems, especially in high productive and, at the same time, overexploited area such as the Adriatic Sea.

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Sensitivity of global gross primary production to elevated CO2

10.5194/egusphere-egu21-1744 ◽

2021 ◽

Author(s):

Wenjia Cai ◽

Iain Colin Prentice

Keyword(s):

Field Experiments ◽

Carbon Sink ◽

Gross Primary Production ◽

Light Response ◽

Terrestrial Ecosystems ◽

Percentage Increase ◽

Terrestrial Plants ◽

Fertilization Effect ◽

Vegetation Models ◽

The Impact

Terrestrial ecosystems have accounted for more than half of the global carbon sink during the past decades and offset 25%-30% of current anthropogenic CO2 emissions. The projected increase in CO2 concentration will depend on the magnitude of terrestrial plants&#8217; feedback to CO2: i.e. the sensitivity of plant carbon uptake in response to elevated CO2, and the strength of the CO2 fertilization effect (CFE) in a changing (and warming) environment. Projecting vegetation responses to future increases in CO2 concentration under climate change is a major uncertainty, as ecosystem models, field experiments and satellite-based models show large disagreements. In this study, using a recently developed, parameter-sparse model (the &#8216;P model&#8217;), we assess the sensitivity of GPP to increasing CO2 under idealized conditions, in comparison with other vegetation models and field experiments. We investigate the impact of two central parameters, the ratio of Jmax to Vcmax (at a common temperature) and the curvature of the light response curve, on the sensitivity of GPP to CO2. We also quantified the spatial-temporal trend of CFE using the &#946; factor, defined as the percentage increase in GPP in response to a 100-ppm increase in atmospheric CO2 concentration over a defined period. We show how modelled &#946; has changed over the satellite era, and infer the possible effect of climatic variables on changes of CFE from spatial patterns of the modelled trend in &#946;.

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