Voici les éléments 1 - 10 sur 92
  • Publication
    Accès libre
    Outils d’évaluation de la diversité et de l’activité des vers de terre : de la science participative à la recherche fondamentale
    (2022-2-1) ;
    Campiche, Sophie
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    Gerber, Valentine
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    Fietier, Amélie
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    Scherrer, Luc
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    Turberg, Pascal
    La compréhension et le suivi du fonctionnement des écosystèmes requièrent l’utilisation d’indicateurs biologiques simples et efficaces. Les vers de terre en font partie et leur étude permet d’appréhender l’écosystème à différents niveaux, depuis les sciences participatives impliquant le grand public à la recherche de pointe nécessitant des compétences scientifiques de haut niveau. Cet article présente une synthèse et une comparaison des techniques et outils actuels pour l’étude des communautés de vers de terre et leurs activités de bioturbation en fonction des objectifs et des besoins des potentiels utilisateurs. Depuis le simple comptage d’animaux au séquençage d’ADN en passant par les techniques de tomographie, l’étude des vers de terre offre un large éventail d’outils et de techniques qui permettent de mieux comprendre leur implication essentielle dans les services écosystémiques.
  • Publication
    Accès libre
    Subordinate plant species moderate drought effects on earthworms communities in grasslands
    (2016-2-13)
    Mariotte, Pierre
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    ;
    Eisenhauer, Nico
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    Guenat, Claire
    ;
    Buttler, Alexandre
    Loss of plant diversity resulting from forecasted drought events is likely to alter soil functioning and affect earthworm communities. Plant-soil interactions are expected to play an important role in mediating climate change effects on soil decomposers. In this study, we test above-belowground linkages after drought by focusing on the effects of subordinate plant species on earthworm communities. Using a combination of subordinate species removal and experimental drought, we show that subordinate species, when present, increased in biomass after drought and induced an increase in total earthworm biomass. These effects were thought to be associated with the maintenance of food quantity and quality (e.g. nitrogen-rich litter) in relation to subordinate species. In support to this hypothesis, we found a positive correlation between the abundance of juvenile earthworms and plant community biomass hence litter quantity, and between the total biomass of earthworms and the abundance of subordinate species. Anecic earthworms were the most benefited by the presence of subordinate species under drought, especially Lumbricus terrestris, which was significantly correlated to the biomass of the nitrogen-rich subordinate species Veronica chamaedrys. Results of a multiple factor analysis (MFA) also highlighted positive associations between earthworm and subordinate species, independently of the drought treatment. Our study highlights how climate change, in this case reduced summer rainfall, can influence plant functional groups, with cascading effects on earthworms. It is therefore crucial, considering forecasted climate change, to understand these processes in order to better predict ecosystem responses and to adapt grassland management.
  • Publication
    Métadonnées seulement
  • Publication
    Accès libre
    Are urban soils similar to natural soils of river valleys?
    Purpose Urban soils and soils of river valleys are constituted of heterogeneous materials that have been manipulated, disturbed or transported at different spatial and temporal scales. Despite these similarities, little is known about soil evolution in urban soils and their comparison with natural soils remains therefore highly useful. We hypothesized that, according to their degree of perturbation, urban soils and natural soils of river valleys have similar soil processes related to their structure, physical and chemical characteristics. Materials and methods Using a synchronic approach, we compared two soil gradients, one located in the natural reserve of the Allondon River (canton of Geneva, Switzerland) and the other in and around the city of Neuchâtel, Switzerland. A total of five alluvial and 18 urban soil profiles were described according to vegetation type and alluvial terraces formed at different distances from the river for the river valley ecosystem and to soil age for the urban ecosystem. Correlations between soil gradients and classical physical (soil depth, particle-size distribution, coarse fraction) and chemical (Corg, pHH2O, Ptot, Ntot, CaCO3, CEC and C/N ratio) parameters of soils were first tested in order to identify similarities and differences among soil gradients. Data of soil properties were then clustered hierarchically in order to identify soil group classification. Results and discussion Our results showed similarities and differences between soil gradients. In the urban context, soil thickness was positively correlated to soil age, while the coarse fraction, sand content and C/N were negatively correlated to soil age gradient. In soils of the river valley, most of the chemical variables were either negatively (pHH2O and CaCO3) or positively (CEC, Corg and Ntot) correlated to soil distance from the river. These differences between gradients can be mainly explained by parent material, depositional conditions and land use which can influence soil processes. However, alluvial soils were well clustered with two identified urban soil groups according to soil maturity. Evolved alluvial soils far from the river were grouped with natural and near natural urban soils. Conversely, “young” perturbed alluvial soils were most clustered with human-made soils. Conclusions From the two selected soil gradients, soils on alluvial sediments are similar to urban soils in some characteristics. However, parent material, depositional conditions and soil and vegetation interactions on soil processes (e.g. matter cycle, energy flux) still need more investigation. This study contributes to the development of a natural soil reference for urban soils.
  • Publication
    Accès libre
    Role of soil macrofauna in P cycling
    (NY, USA: Springer, 2011)
    Chapuis-Lardy, L
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    ; ;
    Lopez-Hernandez, D
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    Blanchard, E
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    Bünemann, E.K
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    Oberson, A
    ;
    Frossard, E
  • Publication
    Accès libre
    A method sheet on microcosms
    (Zürich: COST WSL, 2006) ;
    Jansa, J.
    ;
    Frossard, E.