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Global change is transforming Earth's ecological communities with severe consequences for the functions and services they provide. In temperate grasslands, home to a mesmerising diversity of invertebrates controlling multiple ecosystem processes and services, land-use intensification and climate change are two of the most important global-change drivers. While we know a lot about their independent effects on grassland biodiversity and ecosystem functioning, little is known about how these stressors interact. Moreover, most research on biodiversity change focuses on decreasing biomass or species richness, while a major aspect is commonly ignored - altered ecological interactions. This is problematic because these interactions represent and control many important ecosystem processes, such as predation, herbivory or decomposition. Networks of trophic interactions, so-called food webs, link the structure and functioning of ecological communities and unravel mechanistic relationships between environmental change, ecological communities and ecosystem multifunctionality - the ability of a system to simultaneously support multiple processes. Consequently, we need to study how ecological interactions and the food webs they comprise respond to environmental change and to multiple interacting global-change drivers. Fortunately, novel tools offer unprecedented opportunities in studying trophic interactions and their impact on ecosystem processes. In addition, we know far more about how global change impacts the aboveground world than its belowground counterpart. However, belowground communities are just as important for the overall functioning of terrestrial ecosystems. Thus, to comprehensively understand global-change impacts on temperate grasslands, we need to study above- and belowground multitrophic interactions and ecosystem processes together, also accounting for their interdependencies. Here, we propose to use the Global Change Experimental Facility (GCEF, Bad Lauchstadt, Germany) to study joint impacts of land-use intensity and climate change on above-belowground multitrophic interactions and ecosystem multifunctionality in a temperate grassland global-change experiment. We will combine novel approaches to assessing trophic interactions and basal-resource dependency with an innovative method to quantify energy flux through ecological interaction networks. We will disentangle separate and interactive effects of land use and climate change and unravel how global-change driven modifications in multitrophic interactions mechanistically translate into altered ecosystem processes and multifunctionality - above and below the ground. Combining a field-experimental approach with novel molecular and quantitative techniques will allow for a leap forward in our understanding of global-change impacts on temperate grasslands, which will be crucial to manage and conserve these important ecosystems. [ABSTRACT FROM AUTHOR]

Tropical rainforests around the world are rapidly being converted into cash crop agricultural systems. The associated massive losses of plant and animal species lead to changes in arthropod food webs and the energy fluxes therein. These changes are poorly understood, in particular in the extremely biodiverse canopies of tropical ecosystems. Using canopy fogging followed by stable isotope and energy flux analyses, we show that land‐use conversion from rainforest to rubber and oil palm plantations not only causes a drastic reduction in energy fluxes of up to 75%, but also shifts fluxes among trophic groups. While rainforest featured high levels of both herbivory and algae‐microbivory, and a balanced ratio of herbivory to predation, relative fluxes were shifted towards predation in rubber and towards herbivory in oil palm plantations, indicating profound shifts in ecosystem functioning. Our results highlight that the ongoing loss of animal biodiversity and biomass in tropical canopies degrades animal‐driven functions and restructures canopy food webs. [ABSTRACT FROM AUTHOR]

1.Soil food webs are compartmentalized and comprise major energy channels, such as the plant litter, fungal and bacterial channel. However, the relative contribution of basal resources to these channels for nutrition of higher trophic levels is largely unknown. 2.The study took advantage of the Swiss Canopy Crane Project, where a mature temperate forest was labelled with 13 C-depleted CO2. By exchanging leaf litter between the 13 CO2-enriched area and an unlabelled control area, we were able to separate carbon fluxes originating from leaf litter and roots, respectively. 3.Fatty acid (FA) composition and δ 13 C signatures of individual FAs of basal resources and soil animals, including decomposers and predators, were analysed. Marker FAs allowed differentiation of the contribution of plant litter, fungi and bacteria to the nutrition of higher trophic levels. 4.Our findings suggest that root-derived carbon is of major importance for the soil animal food web and that it enters the soil animal food web mainly via feeding on ectomycorrhizal fungi. 5.In contrast to previous studies that emphasized the dominance of the fungal energy channel, significant amounts of bacterial FAs in each of the predator species studied indicate that the bacterial energy channel is considerably more important for the nutrition of higher trophic levels than previously assumed. The flux of energy along the two channels presumably contributes to food web stability. 6.Compound-specific 13( CO2) FA analysis of basal resources and soil animals allowed the separation of energy fluxes originating from ectomycorrhizal vs. saprotrophic fungi, from bacteria feeding on leaf litter vs. bacteria feeding on root exudates, and from leaf litter itself, providing information on the partitioning of these different energy channels in unprecedented detail. [ABSTRACT FROM AUTHOR]

Abstract: The soil animal food web has become a focus of recent ecological research but trophic relationships still remain enigmatic for many taxa. Analysis of stable isotope ratios of N and C provides a powerful tool for disentangling food web structure. In this study, animals, roots, soil and litter material from a temperate deciduous forest were analysed. The combined measurement of δ 15N and δ 13C provided insights into the compartmentalization of the soil animal food web. Leaf litter feeders were separated from animals relying mainly on recent belowground carbon resources and from animals feeding on older carbon. The trophic pathway of leaf litter-feeding species appears to be a dead end, presumably because leaf litter feeders (mainly diplopods and oribatid mites) are unavailable to predators due to large size and/or strong sclerotization. Endogeic earthworms that rely on older carbon also appear to exist in predator-free space. The data suggest that the largest trophic compartment constitutes of ectomycorrhizal feeders and their predators. Additionally, there is a smaller trophic compartment consisting of predators likely feeding on enchytraeids and potentially nematodes. [Copyright &y& Elsevier]