Cascading effects of moth outbreaks on subarctic soil food webs

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.

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Cascading Effects of Moth Outbreaks on Subarctic Soil Food Webs

10.21203/rs.3.rs-228461/v1 ◽

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.

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Contrasting responses of above- and belowground diversity to multiple components of land-use intensity

Nature Communications ◽

10.1038/s41467-021-23931-1 ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Gaëtane Le Provost ◽

Jan Thiele ◽

Catrin Westphal ◽

Caterina Penone ◽

Eric Allan ◽

...

Keyword(s):

Land Use ◽

Forest Cover ◽

Spatial Scales ◽

Biodiversity Loss ◽

Trophic Levels ◽

Land Use Intensity ◽

Trophic Groups ◽

Multiple Components ◽

Belowground Diversity ◽

Landscape Level

AbstractLand-use intensification is a major driver of biodiversity loss. However, understanding how different components of land use drive biodiversity loss requires the investigation of multiple trophic levels across spatial scales. Using data from 150 agricultural grasslands in central Europe, we assess the influence of multiple components of local- and landscape-level land use on more than 4,000 above- and belowground taxa, spanning 20 trophic groups. Plot-level land-use intensity is strongly and negatively associated with aboveground trophic groups, but positively or not associated with belowground trophic groups. Meanwhile, both above- and belowground trophic groups respond to landscape-level land use, but to different drivers: aboveground diversity of grasslands is promoted by diverse surrounding land-cover, while belowground diversity is positively related to a high permanent forest cover in the surrounding landscape. These results highlight a role of landscape-level land use in shaping belowground communities, and suggest that revised agroecosystem management strategies are needed to conserve whole-ecosystem biodiversity.

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

Biology Letters ◽

10.1098/rsbl.2021.0353 ◽

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.

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

Oikos ◽

10.1111/j.1600-0706.2013.00872.x ◽

2014 ◽

Vol 123 (10) ◽

pp. 1199-1211 ◽

Cited By ~ 37

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

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Environmentally triggered evolutionary cascade across trophic levels in an experimental phage-bacteria-insect system

10.1101/850248 ◽

2019 ◽

Cited By ~ 1

Author(s):

Matthieu Bruneaux ◽

Roghaieh Ashrafi ◽

Ilkka Kronholm ◽

Anni-Maria Örmälä-Odegrip ◽

Juan A. Galarza ◽

...

Keyword(s):

Environmental Effects ◽

Large Scale ◽

Environmental Changes ◽

Galleria Mellonella ◽

Biotic Interactions ◽

Trophic Levels ◽

Lytic Cycle ◽

Biological Interactions ◽

Insect Host ◽

Cascading Effects

AbstractEnvironmental changes can cause strong cascading effects in species communities due to altered biological interactions between species (Zarnetske et al., 2012). Highly specialized interactions arising from the co-evolution of hosts and parasites, such as bacteria and phages, and short generation times of these species could rapidly lead to considerable evolutionary changes in their biotic interactions (Kerr, 2012; Buck and Ripple, 2017), with potential large-scale ramifications to other trophic levels. Here we report experimental evidence of cascading environmental effects across trophic levels in an experimental system where phage-bacteria coevolution in an abiotically altered environment cascaded on bacterial virulence in an insect host. We found that the lytic cycle of the temperate phage KPS20 induced at low temperatures led to selection in the bacterial host Serratia marcescens that tempered the likelihood of triggering the phage’s lytic cycle. These changes in S. marcescens concomitantly attenuated its virulence in an insect host, Galleria mellonella. In addition, our data suggests that this effect is mediated by mutations and epigenetic modifications of bacterial genes moderating the onset of the temperate phage’s lytic cycle. Given the abundance of temperate phages in bacterial genomes (Canchaya et al., 2003), the sensitivity of the onset of their lytic cycle to environmental conditions (Howard-Varona et al., 2017), and the predominance of environmental change due to climate change, our results warrants attention as a cautionary example of the dangers of predicting environmental effects on species without considering complex biotic interactions.

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Interaction between top-down and bottom-up control in marine food webs

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1621037114 ◽

2017 ◽

Vol 114 (8) ◽

pp. 1952-1957 ◽

Cited By ~ 69

Author(s):

Christopher Philip Lynam ◽

Marcos Llope ◽

Christian Möllmann ◽

Pierre Helaouët ◽

Georgia Anne Bayliss-Brown ◽

...

Keyword(s):

Food Webs ◽

North Sea ◽

Time Series Data ◽

Trophic Levels ◽

Series Data ◽

Resource Exploitation ◽

Top Down ◽

Bottom Up ◽

Cascading Effects ◽

Complex Patterns

Climate change and resource exploitation have been shown to modify the importance of bottom-up and top-down forces in ecosystems. However, the resulting pattern of trophic control in complex food webs is an emergent property of the system and thus unintuitive. We develop a statistical nondeterministic model, capable of modeling complex patterns of trophic control for the heavily impacted North Sea ecosystem. The model is driven solely by fishing mortality and climatic variables and based on time-series data covering >40 y for six plankton and eight fish groups along with one bird group (>20 y). Simulations show the outstanding importance of top-down exploitation pressure for the dynamics of fish populations. Whereas fishing effects on predators indirectly altered plankton abundance, bottom-up climatic processes dominate plankton dynamics. Importantly, we show planktivorous fish to have a central role in the North Sea food web initiating complex cascading effects across and between trophic levels. Our linked model integrates bottom-up and top-down effects and is able to simulate complex long-term changes in ecosystem components under a combination of stressor scenarios. Our results suggest that in marine ecosystems, pathways for bottom-up and top-down forces are not necessarily mutually exclusive and together can lead to the emergence of complex patterns of control.

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Widespread decline in plant diversity across six decades

10.1101/2020.08.31.275461 ◽

2020 ◽

Author(s):

Eichenberg David ◽

Diana E. Bowler ◽

Bonn Aletta ◽

Bruelheide Helge ◽

Grescho Volker ◽

...

Keyword(s):

Plant Species ◽

Native Species ◽

Large Scale ◽

Grid Cell ◽

Trophic Levels ◽

Native Plant ◽

Cascading Effects ◽

Occurrence Data ◽

Temporal Models ◽

The 1960S

AbstractBased on plant occurrence data covering all parts of Germany, we investigated changes in the distribution of 2146 plant species between 1960 and 2017. We analyzed 29 million occurrence records over an area of ∼350.000 km2 on a 5 × 5 km grid using temporal and spatio-temporal models and accounting for sampling bias. Since the 1960s, more than 70% of investigated plant species showed significant declines in nation-wide occurrence. Archaeophytes (species introduced before 1492) most strongly declined but also native plant species experienced severe declines. In contrast, neophytes (species introduced after 1492) increased in their nation-wide occurrence but not homogeneously throughout the country. Our analysis suggests that the strongest declines in native species already happened in the 1960s-80s, a time frame in which usually few data exist. Increases in neophytic species were strongest in the 1990s and 2010s. Overall, the increase in neophytes did not compensate for the loss of other species, resulting in a decrease in mean grid-cell species-richness of -1.9% per decade. The decline in plant biodiversity is a widespread phenomenon occurring in different habitats and geographic regions. It is likely that this decline has major repercussions on ecosystem functioning and overall biodiversity, potentially with cascading effects across trophic levels. The approach used in this study is transferable to large-scale trend analyses using heterogeneous occurrence data.

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

Oecologia ◽

10.1007/s00442-014-3037-0 ◽

2014 ◽

Vol 176 (2) ◽

pp. 487-496 ◽

Cited By ~ 8

Author(s):

Kathleen Lemanski ◽

Stefan Scheu

Keyword(s):

Food Webs ◽

Trophic Levels ◽

Soil Food Webs ◽

Microbial Carbon

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

Proceedings of The Royal Society B Biological Sciences ◽

10.1098/rspb.2020.1268 ◽

2020 ◽

Vol 287 (1934) ◽

pp. 20201268 ◽

Cited By ~ 1

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.

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