Fertilizer addition lessens the flux of microbial carbon to higher trophic levels in soil food webs of grassland

Oecologia ◽  
2014 ◽  
Vol 176 (2) ◽  
pp. 487-496 ◽  
Author(s):  
Kathleen Lemanski ◽  
Stefan Scheu
Keyword(s):  
Food Webs ◽  
Trophic Levels ◽  
Soil Food Webs ◽  
Microbial Carbon

scholarly journals Radiocarbon signature reveals that most springtails depend on carbon from living plants

2021 ◽  
Vol 17 (9) ◽  
pp. 20210353
Author(s):  
Saori Fujii ◽  
Takashi F. Haraguchi ◽  
Ichiro Tayasu
Keyword(s):  
Food Webs ◽  
Carbon Cycling ◽  
Feeding Habits ◽  
Significant Negative Correlation ◽  
Trophic Levels ◽  
Soil Microarthropods ◽  
Soil Food Webs ◽  
Animal Feeding ◽  
Taxonomic Groups ◽  
Isotope Analyses

Terrestrial carbon cycling is largely mediated by soil food webs. Identifying the carbon source for soil animals has been desired to distinguish their roles in carbon cycling, but it is challenging for small invertebrates at low trophic levels because of methodological limitations. Here, we combined radiocarbon ( 14 C) analysis with stable isotope analyses ( 13 C and 15 N) to understand feeding habits of soil microarthropods, especially focusing on springtail (Collembola). Most Collembola species exhibited lower Δ 14 C values than litter regardless of their δ 13 C and δ 15 N signatures, indicating their dependence on young carbon. In contrast with general patterns across all taxonomic groups, we found a significant negative correlation between δ 15 N and Δ 14 C values among the edaphic Collembola. This means that the species with higher δ 15 N values depend on C from more recent photosynthate, which suggests that soil-dwelling species generally feed on mycorrhizae to obtain root-derived C. Many predatory taxa exhibited higher Δ 14 C values than Collembola but lower than litter, indicating non-negligible effects of collembolan feeding habits on the soil food web. Our study demonstrated the usefulness of radiocarbon analysis, which can untangle the confounding factors that change collembolan δ 15 N values, clarify animal feeding habits and define the roles of organisms in soil food webs.

scholarly journals Cascading Effects of Moth Outbreaks on Subarctic Soil Food Webs

2021 ◽  
Author(s):  
Irene Calderón-Sanou ◽  
Tamara Münkemüller ◽  
Lucie Zinger ◽  
Heidy Schimann ◽  
Nigel Gilles Yoccoz ◽  
...  
Keyword(s):  
Food Webs ◽  
Large Scale ◽  
Trophic Levels ◽  
Trophic Groups ◽  
Holistic View ◽  
Cascading Effects ◽  
Soil Food Webs ◽  
Network Analyses ◽  
Northern Fennoscandia ◽  
Belowground Diversity

Abstract The increasing severity and frequency of natural disturbances requires a better understanding of their effects on all compartments of biodiversity. In Northern Fennoscandia, recent large-scale moth outbreaks have led to an abrupt change in plant communities from birch forests dominated by dwarf shrubs to grass-dominated systems. However, the indirect effects on the belowground compartment remained unclear. Here, we combined eDNA survey of multiple trophic groups with network analyses to demonstrate that moth defoliation has far-reaching consequences on soil food webs. Following this disturbance, diversity and relative abundance of certain trophic groups declined (e.g. ectomycorrhizal fungi) while many others profited (e.g. bacterivores, omnivores) making soil food webs more diverse and structurally different. Overall, the direct and indirect consequences of moth outbreaks increased belowground diversity at different trophic levels. Our results highlight that a holistic view of ecosystems improves our understanding of cascading effects of major disturbances on soil food webs.

Free-living nematodes as prey for higher trophic levels of forest soil food webs

Oikos ◽  
2014 ◽  
Vol 123 (10) ◽  
pp. 1199-1211 ◽  
Author(s):  
Kerstin Heidemann ◽  
Annika Hennies ◽  
Johanna Schakowske ◽  
Lars Blumenberg ◽  
Liliane Ruess ◽  
...  
Keyword(s):  
Food Webs ◽  
Forest Soil ◽  
Trophic Levels ◽  
Free Living ◽  
Soil Food Webs

scholarly journals Microplastics negatively affect soil fauna but stimulate microbial activity: insights from a field-based microplastic addition experiment

2020 ◽  
Vol 287 (1934) ◽  
pp. 20201268 ◽  
Author(s):  
Dunmei Lin ◽  
Guangrong Yang ◽  
Pengpeng Dou ◽  
Shenhua Qian ◽  
Liang Zhao ◽  
...  
Keyword(s):  
Food Webs ◽  
Structural Equation ◽  
Soil Fauna ◽  
Soil Microbial Communities ◽  
Ecological Impacts ◽  
Trophic Levels ◽  
Soil Community ◽  
Soil Microbial ◽  
Soil Food Webs ◽  
Manipulation Experiment

Microplastics are recognized as an emerging contaminant worldwide. Although microplastics have been shown to strongly affect organisms in aquatic environments, less is known about whether and how microplastics can affect different taxa within a soil community, and it is unclear whether these effects can cascade through soil food webs. By conducting a microplastic manipulation experiment, i.e. adding low-density polyethylene fragments in the field, we found that microplastic addition significantly affected the composition and abundance of microarthropod and nematode communities. Contrary to soil fauna, we found only small effects of microplastics on the biomass and structure of soil microbial communities. Nevertheless, structural equation modelling revealed that the effects of microplastics strongly cascade through the soil food webs, leading to the modification of microbial functioning with further potential consequences on soil carbon and nutrient cycling. Our results highlight that taking into account the effects of microplastics at different trophic levels is important to elucidate the mechanisms underlying the ecological impacts of microplastic pollution on soil functioning.

Unravelling the complex structure of forest soil food webs: higher omnivory and more trophic levels

Oikos ◽  
2014 ◽  
Vol 123 (10) ◽  
pp. 1157-1172 ◽  
Author(s):  
Christoph Digel ◽  
Alva Curtsdotter ◽  
Jens Riede ◽  
Bernhard Klarner ◽  
Ulrich Brose
Keyword(s):  
Food Webs ◽  
Forest Soil ◽  
Complex Structure ◽  
Trophic Levels ◽  
Soil Food Webs

scholarly journals Cascading effects of moth outbreaks on subarctic soil food webs

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Irene Calderón-Sanou ◽  
Tamara Münkemüller ◽  
Lucie Zinger ◽  
Heidy Schimann ◽  
Nigel Gilles Yoccoz ◽  
...  
Keyword(s):  
Food Webs ◽  
Large Scale ◽  
Trophic Levels ◽  
Trophic Groups ◽  
Holistic View ◽  
Cascading Effects ◽  
Soil Food Webs ◽  
Network Analyses ◽  
Northern Fennoscandia ◽  
Belowground Diversity

AbstractThe increasing severity and frequency of natural disturbances requires a better understanding of their effects on all compartments of biodiversity. In Northern Fennoscandia, recent large-scale moth outbreaks have led to an abrupt change in plant communities from birch forests dominated by dwarf shrubs to grass-dominated systems. However, the indirect effects on the belowground compartment remained unclear. Here, we combined eDNA surveys of multiple trophic groups with network analyses to demonstrate that moth defoliation has far-reaching consequences on soil food webs. Following this disturbance, diversity and relative abundance of certain trophic groups declined (e.g., ectomycorrhizal fungi), while many others expanded (e.g., bacterivores and omnivores) making soil food webs more diverse and structurally different. Overall, the direct and indirect consequences of moth outbreaks increased belowground diversity at different trophic levels. Our results highlight that a holistic view of ecosystems improves our understanding of cascading effects of major disturbances on soil food webs.

scholarly journals Elevated temperature and browning increase dietary methylmercury, but decrease essential fatty acids at the base of lake food webs

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Pianpian Wu ◽  
Martin J. Kainz ◽  
Fernando Valdés ◽  
Siwen Zheng ◽  
Katharina Winter ◽  
...  
Keyword(s):  
Climate Change ◽  
Fatty Acids ◽  
Organic Matter ◽  
Food Webs ◽  
Essential Fatty Acids ◽  
Trophic Levels ◽  
Climate Change Scenarios ◽  
Essential Nutrients ◽  
Aquatic Food Webs ◽  
Aquatic Food

AbstractClimate change scenarios predict increases in temperature and organic matter supply from land to water, which affect trophic transfer of nutrients and contaminants in aquatic food webs. How essential nutrients, such as polyunsaturated fatty acids (PUFA), and potentially toxic contaminants, such as methylmercury (MeHg), at the base of aquatic food webs will be affected under climate change scenarios, remains unclear. The objective of this outdoor mesocosm study was to examine how increased water temperature and terrestrially-derived dissolved organic matter supply (tDOM; i.e., lake browning), and the interaction of both, will influence MeHg and PUFA in organisms at the base of food webs (i.e. seston; the most edible plankton size for zooplankton) in subalpine lake ecosystems. The interaction of higher temperature and tDOM increased the burden of MeHg in seston (< 40 μm) and larger sized plankton (microplankton; 40–200 μm), while the MeHg content per unit biomass remained stable. However, PUFA decreased in seston, but increased in microplankton, consisting mainly of filamentous algae, which are less readily bioavailable to zooplankton. We revealed elevated dietary exposure to MeHg, yet decreased supply of dietary PUFA to aquatic consumers with increasing temperature and tDOM supply. This experimental study provides evidence that the overall food quality at the base of aquatic food webs deteriorates during ongoing climate change scenarios by increasing the supply of toxic MeHg and lowering the dietary access to essential nutrients of consumers at higher trophic levels.

Functional diversity alters the effects of a pulse perturbation on the dynamics of tritrophic food webs

2021 ◽  
Author(s):  
Ruben Ceulemans ◽  
Laurie Anne Myriam Wojcik ◽  
Ursula Gaedke
Keyword(s):  
Food Web ◽  
Food Webs ◽  
Functional Diversity ◽  
Feedback Loop ◽  
Environmental Changes ◽  
Biodiversity Loss ◽  
Trophic Levels ◽  
Nutrient Pulse ◽  
Trade Offs ◽  
Food Web Model

Biodiversity decline causes a loss of functional diversity, which threatens ecosystems through a dangerous feedback loop: this loss may hamper ecosystems' ability to buffer environmental changes, leading to further biodiversity losses. In this context, the increasing frequency of climate and human-induced excessive loading of nutrients causes major problems in aquatic systems. Previous studies investigating how functional diversity influences the response of food webs to disturbances have mainly considered systems with at most two functionally diverse trophic levels. Here, we investigate the effects of a nutrient pulse on the resistance, resilience and elasticity of a tritrophic---and thus more realistic---plankton food web model depending on its functional diversity. We compare a non-adaptive food chain with no diversity to a highly diverse food web with three adaptive trophic levels. The species fitness differences are balanced through trade-offs between defense/growth rate for prey and selectivity/half-saturation constant for predators. We showed that the resistance, resilience and elasticity of tritrophic food webs decreased with larger perturbation sizes and depended on the state of the system when the perturbation occured. Importantly, we found that a more diverse food web was generally more resistant, resilient, and elastic. Particularly, functional diversity dampened the probability of a regime shift towards a non-desirable alternative state. In addition, despite the complex influence of the shape and type of the dynamical attractors, the basal-intermediate interaction determined the robustness against a nutrient pulse. This relationship was strongly influenced by the diversity present and the third trophic level. Overall, using a food web model of realistic complexity, this study confirms the destructive potential of the positive feedback loop between biodiversity loss and robustness, by uncovering mechanisms leading to a decrease in resistance, resilience and elasticity as functional diversity declines.

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