scholarly journals Analysis of complex trophic networks reveals the signature of land-use intensification on soil communities in agroecosystems

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Juliette M. G. Bloor ◽  
Sara Si-Moussi ◽  
Pierre Taberlet ◽  
Pascal Carrère ◽  
Mickaël Hedde
Keyword(s):  
Land Use ◽  
Food Web ◽  
Agricultural Intensification ◽  
Environmental Dna ◽  
Trophic Group ◽  
Interaction Networks ◽  
Land Use Intensity ◽  
Food Web Structure ◽  
Trophic Networks ◽  
Management Intensity

AbstractIncreasing evidence suggests that agricultural intensification is a threat to many groups of soil biota, but how the impacts of land-use intensity on soil organisms translate into changes in comprehensive soil interaction networks remains unclear. Here for the first time, we use environmental DNA to examine total soil multi-trophic diversity and food web structure for temperate agroecosystems along a gradient of land-use intensity. We tested for response patterns in key properties of the soil food webs in sixteen fields ranging from arable crops to grazed permanent grasslands as part of a long-term management experiment. We found that agricultural intensification drives reductions in trophic group diversity, although taxa richness remained unchanged. Intensification generally reduced the complexity and connectance of soil interaction networks and induced consistent changes in energy pathways, but the magnitude of management-induced changes depended on the variable considered. Average path length (an indicator of food web redundancy and resilience) did not respond to our management intensity gradient. Moreover, turnover of network structure showed little response to increasing management intensity. Our data demonstrates the importance of considering different facets of trophic networks for a clearer understanding of agriculture-biodiversity relationships, with implications for nature-based solutions and sustainable agriculture.

scholarly journals Spatio-temporal patterns of multi-trophic biodiversity and food-web characteristics across a river catchment

2021 ◽  
Author(s):  
Rosetta C Blackman ◽  
Hsi-Cheng Ho ◽  
Jean-Claude Walser ◽  
Florian Altermatt
Keyword(s):  
Food Web ◽  
Environmental Dna ◽  
Ecological Communities ◽  
Food Web Structure ◽  
Spatial And Temporal Scales ◽  
Natural Systems ◽  
Α Diversity ◽  
Link Density ◽  
Spatio Temporal ◽  
Taxonomic Groups

Accurate characterisation of ecological communities with respect to their biodiversity and food-web structure is essential for conservation. However, combined empirical study of biodiversity and multi-trophic food webs at a large spatial and temporal resolution has been prohibited by the lack of appropriate access to such data from natural systems. Here, we assessed biodiversity and food-web characteristics across a 700 km2 riverine network through time using environmental DNA. We find contrasting biodiversity patterns, with richness (α-diversity) of fish increasing towards downstream positions within the catchment, while freshwater bacteria and invertebrates having an invariant and minimal decrease in richness, respectively, with downstream position. Food-web characteristics, such as link density and nestedness, however, were relatively conserved across space, but varied over season. Patterns of biodiversity across major taxonomic groups are thus not directly scalable to food-web structures at the same spatial and temporal scales, indicating that effective conservation measures must consider them jointly.

Paleobiology of Predators, Parasitoids, and Parasites: Death and Accomodation in the Fossil Record of Continental Invertebrates

2002 ◽  
Vol 8 ◽  
pp. 211-250 ◽  
Author(s):  
Conrad C. Labandeira
Keyword(s):  
Food Web ◽  
Fossil Record ◽  
Terrestrial Ecosystems ◽  
Trophic Group ◽  
Freshwater Ecosystems ◽  
Gut Contents ◽  
Future Research ◽  
Good Representation ◽  
Ecosystem Structure ◽  
Food Web Structure

Carnivory is the consumption of one animal by another animal; among invertebrates in terrestrial and freshwater ecosystems this type of feeding can take three forms: predation, parasitoidism, and parasitism. Differences among these three functional modes involve (i) whether the duration of feeding on the prey item is quick or there is an accommodation, coevolutionary or otherwise, between the carnivore and the host prey; (ii) whether the prey or host is killed; (iii) whether single or multiple prey or host items are consumed during the carnivore's lifespan, and (iv) the relative sizes of the carnivore and its prey or host. Uniformitarian and nonuniformitarian evidence directly relating to the history of carnivory can be found in exceptionally preserved deposits from the mid-Paleozoic to the Recent, but such evidence is relatively rare because carnivores are the least represented trophic group in ecosystems. Six types of paleobiological data provide evidence for carnivory: taxonomic affiliation, fossil structural and functional attributes, organismic damage, gut contents, coprolites, and indications of mechanisms for predator avoidance.Only 12 invertebrate phyla have become carnivorous in the continental realm. Six are lophotrochozoans (Acanthocephala, Rotifera, Platyhelminthes, Nemertinea, Mollusca, and Annelida) and six are ecdysozoans (Nematoda, Nematomorpha, Tardigrada, Onychophora, Pentastoma, and Arthropoda). Most of these groups have poor continental fossil records, but the two most diverse—nematodes and arthropods—have comparatively good representation. The record of arthropods documents (i) the presence of predators among primary producers, herbivores, and decomposers in early terrestrial ecosystems; (ii) the addition later in the fossil record of the more accommodationist strategies of parasitoids and parasites interacting with animal hosts; (iii) the occurrence of simpler food-web structures in terrestrial ecosystems prior to parasitoid and parasite diversification; and (iv) a role for mass extinction in the degradation of food-web structure that ultimately affected carnivory. Future research should explore how different modes of carnivory have brought about changes in ecosystem structure through time. Despite numerous caveats and uncertainties, trace fossils left by predators on skeletons of their prey remain one of the most promising research directions in paleoecology and evolutionary paleobiology.

scholarly journals Relevance of evolutionary history for food web structure

2011 ◽  
Vol 279 (1733) ◽  
pp. 1588-1596 ◽  
Author(s):  
Anna Eklöf ◽  
Matthew R. Helmus ◽  
M. Moore ◽  
Stefano Allesina
Keyword(s):  
Food Web ◽  
Species Interactions ◽  
Evolutionary History ◽  
Species Traits ◽  
Interaction Networks ◽  
Food Web Structure ◽  
Feeding Mode ◽  
Closely Related Species ◽  
Marginal Likelihoods ◽  
Web Structure

Explaining the structure of ecosystems is one of the great challenges of ecology. Simple models for food web structure aim at disentangling the complexity of ecological interaction networks and detect the main forces that are responsible for their shape. Trophic interactions are influenced by species traits, which in turn are largely determined by evolutionary history. Closely related species are more likely to share similar traits, such as body size, feeding mode and habitat preference than distant ones. Here, we present a theoretical framework for analysing whether evolutionary history—represented by taxonomic classification—provides valuable information on food web structure. In doing so, we measure which taxonomic ranks better explain species interactions. Our analysis is based on partitioning of the species into taxonomic units. For each partition, we compute the likelihood that a probabilistic model for food web structure reproduces the data using this information. We find that taxonomic partitions produce significantly higher likelihoods than expected at random. Marginal likelihoods (Bayes factors) are used to perform model selection among taxonomic ranks. We show that food webs are best explained by the coarser taxonomic ranks (kingdom to class). Our methods provide a way to explicitly include evolutionary history in models for food web structure.

scholarly journals Identifying patterns in the multitrophic community and food-web structure of a low-turbidity temperate estuarine bay

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Hee Yoon Kang ◽  
Changseong Kim ◽  
Dongyoung Kim ◽  
Young-Jae Lee ◽  
Hyun Je Park ◽  
...  
Keyword(s):  
Community Structure ◽  
Food Web ◽  
Water Channel ◽  
Mixing Models ◽  
Self Organizing Map ◽  
Food Web Structure ◽  
Trophic Networks ◽  
Nekton Communities ◽  
Isotope Mixing Models ◽  
Estuarine Coastal

Abstract Food web dynamics outline the ecosystem processes that regulate community structure. Challenges in the approaches used to capture topological descriptions of food webs arise due to the difficulties in collecting extensive empirical data with temporal and spatial variations in community structure and predator–prey interactions. Here, we use a Kohonen self-organizing map algorithm (as a measure of community pattern) and stable isotope-mixing models (as a measure of trophic interaction) to identify food web patterns across a low-turbidity water channel of a temperate estuarine-coastal continuum. We find a spatial difference in the patterns of community compositions between the estuarine and deep-bay channels and a seasonal difference in the plankton pattern but less in the macrobenthos and nekton communities. Dietary mixing models of co-occurring dominant taxa reveal site-specific but unchanging food web topologies and the prominent role of phytoplankton in the trophic base of pelagic and prevalent-detrital benthic pathways. Our approach provides realistic frameworks for linking key nodes from producers to predators in trophic networks.

scholarly journals Agricultural Transformations in the Southern Cone of Latin America: Agricultural Intensification and Decrease of the Aboveground Net Primary Production, Uruguay’s Case

2019 ◽  
Vol 11 (24) ◽  
pp. 7011 ◽  
Author(s):  
Inés Gazzano ◽  
Marcel Achkar ◽  
Ismael Díaz
Keyword(s):  
Land Use ◽  
Primary Production ◽  
Agricultural Intensification ◽  
Net Primary Production ◽  
Strong Impact ◽  
Land Use Intensity ◽  
Dynamic Adjustment ◽  
Aboveground Net Primary Production ◽  
Intensity Index ◽  
Productive Potential

The agri-exporting enclaves of the current corporate food regime intensively exploit natural assets in global strategies that govern the local processes. Their multidimensional impacts contribute to the environmental and civilizational crisis. Linked to the agrarian metabolism in its appropriation phase, land use has impacts on local systems. To understand this process, it is necessary to identify the systemic and spatial expression of environmental transformation. The objective of this work was to analyze the dynamic adjustment of aboveground net primary production (ANPP) to agricultural intensification between the years 2000 and 2017, using a land use intensity index and the soils’ productive potential. Agricultural expansion and consolidation are observed, as well as the significant intensification throughout the period in 65% of the country’s area—with differences between regions—associated with soil types. ANPP is higher in areas of low land use intensity and lower in high intensity areas, varying from high to low in soils with low to high productive potential, respectively, and growing throughout the period—depending on the area, with less growth in areas of greater intensity. The appropriation of edaphic wealth puts the systemic functionality at risk and challenges these transforming dynamics, with a strong impact on southern systems.

scholarly journals Enriching plant diversity in grasslands by large-scale experimental sward disturbance and seed addition along gradients of land-use intensity

2016 ◽  
pp. rtw062 ◽  
Author(s):  
Valentin H. Klaus ◽  
Deborah Schäfer ◽  
Till Kleinebecker ◽  
Markus Fischer ◽  
Daniel Prati ◽  
...  
Keyword(s):  
Land Use ◽  
Plant Diversity ◽  
Large Scale ◽  
Land Use Intensity ◽  
Seed Addition

Variation in regrowth ability in relation to land-use intensity in three common grassland herbs

2021 ◽  
Author(s):  
Anna Kirschbaum ◽  
Oliver Bossdorf ◽  
J F Scheepens
Keyword(s):  
Land Use ◽  
Phenotypic Plasticity ◽  
Temporal Variation ◽  
Temporal Stability ◽  
Common Garden ◽  
Grassland Management ◽  
Land Use Intensity ◽  
Evolutionary Changes ◽  
Biomass Removal ◽  
Reproductive Biomass

Abstract Aims Plant populations in managed grasslands are subject to strong selection exerted by grazing, mowing and fertilization. Many previous studies showed that this can cause evolutionary changes in mean trait values, but little is known about the evolution of phenotypic plasticity in response to land use. In this study, we aimed to elucidate the relationships between phenotypic plasticity – specifically, regrowth ability after biomass removal – and the intensity of grassland management and levels of temporal variation therein. Methods We conducted an outdoor common garden experiment to test if plants from more intensively mown and grazed sites showed an increased ability to regrow after biomass removal. We used three common plant species from temperate European grasslands, with seed material from 58 – 68 populations along gradients of land-use intensity, ranging from extensive (only light grazing) to very intensive management (up to four cuts per year). Important findings In two out of three species, we found significant population differentiation in regrowth ability after clipping. While variation in regrowth ability was unrelated to the mean land-use intensity of populations of origin, we found a relationship with its temporal variation in P. lanceolata, where plants experiencing less variable environmental conditions over the last 11 years showed stronger regrowth in reproductive biomass after clipping. Therefore, while mean grazing and mowing intensity may not select for regrowth ability, the temporal stability of the environmental heterogeneity created by land use may have caused its evolution in some species.

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