Effects of liming on macroinvertebrates diversity in forest soils and some associated functional processes in the Vosges Mountains (North-eastern, France)

Le recours à des épandages d'amendements calco-magnésiens dans les forêts acidifiées peut représenter une alternative intéressante pour corriger l'acidification des sols et la perte d'éléments nutritifs engendrés par des décennies de dépôts atmosphériques acides. Dans ce contexte, les objectifs de cette thèse sont d'évaluer les effets d'amendements calco-magnésiens sur (i) la diversité taxonomique et la structure des communautés des macroinvertébrés de sol forestier et sur (ii) deux processus fonctionnels associés notamment à l'activité des vers de terre, tels que la structuration du sol et l'évolution des humus. Au cours de nos travaux, trois sites localisés dans les Vosges (nord-est, France) ont été étudiés : deux massifs forestiers (sur grès et granite) en moyenne montagne, ayant fait l'objet d'amendements aériens en 2003 et la forêt domaniale de Humont située dans les collines sous-vosgiennes, où des amendements en 1991 et 2008 ont été réalisés. Les résultats montrent que 4 ans après amendement sur les bassins versants en moyenne montagne, l'abondance totale de la communauté de macrofaune a diminué, alors que les richesses spécifiques sont similaires. Cependant, la composition des communautés diffère avec moins de 50 % d'espèces communes aux sites amendés et témoins. Une diminution de l'abondance des prédateurs a également été observée alors que la plupart des détritivores ont été favorisés par l'amendement. Les études in vitro montrent également son effet positif sur les activités de structuration du sol par les vers de terre (production de turricules et construction de galeries). En forêt de Humont, les amendements ont eu un effet majeur à moyen terme (4 ans) et à long terme (20 ans) sur la population d'Aporrectodea velox, espèce endémique des Vosges. De part sa biomasse importante, cette augmentation de densité favorise l'amélioration des caractéristiques physico-chimiques du sol forestier tels que la structuration des sols et la morphologie des humus.The use of liming (Ca-Mg) on acidified forest can be interesting to counteract soil acidification and loss of nutrients caused by decades of acid atmospheric deposition. In this context, the aims of this work were to assess liming effect on (i) taxonomical diversity and community structure of soil macro-invertebrates and on (ii) two associated functional processes related to earthworms: soil structuration and humus evolution. The PhD project was realised in three sites from the Vosges mountains (North-eastern, France): two forest mountain catchments (one lying on sandstone and the other on granite) limed in 2003 and the public hill forest of Humont at a lower altitude limed in 1991 and 2008. Results showed that 4 years after liming in mountain forest, the total abundance of macro-invertebrates decreased, while the species richness were similar. However, the community structure strongly differed, and less than 50% of the species were common to limed and control sites. Moreover, 43 species appeared to be indicators of liming. Predator taxa abundance decreased whereas the detritivorous were favoured by lime addition. The in vitro experiments showed a positive effect of liming on soil structuration by earthworm activities (cast production and burrowing activities). In the Humont forest, liming at medium-term (4 years) and long term (20 years) have an important effect on the Aporrectodea velox population, an endemic vosgian species. Related to its high biomass, this increase strongly improved soil physicochemical parameters such as soil structure and humus morphology

Impact d'amendements calco-magnésiens sur la diversité des macroinvertébrés de sols forestiers et sur certains processus fonctionnels associés. Cas du massif vosgien (nord-est, France)

The use of liming (Ca-Mg) on acidified forest can be interesting to counteract soil acidification and loss of nutrients caused by decades of acid atmospheric deposition. In this context, the aims of this work were to assess liming effect on (i) taxonomical diversity and community structure of soil macro-invertebrates and on (ii) two associated functional processes related to earthworms: soil structuration and humus evolution. The PhD project was realised in three sites from the Vosges mountains (North-eastern, France): two forest mountain catchments (one lying on sandstone and the other on granite) limed in 2003 and the public hill forest of Humont at a lower altitude limed in 1991 and 2008. Results showed that 4 years after liming in mountain forest, the total abundance of macro-invertebrates decreased, while the species richness were similar. However, the community structure strongly differed, and less than 50% of the species were common to limed and control sites. Moreover, 43 species appeared to be indicators of liming. Predator taxa abundance decreased whereas the detritivorous were favoured by lime addition. The in vitro experiments showed a positive effect of liming on soil structuration by earthworm activities (cast production and burrowing activities). In the Humont forest, liming at medium-term (4 years) and long term (20 years) have an important effect on the Aporrectodea velox population, an endemic vosgian species. Related to its high biomass, this increase strongly improved soil physicochemical parameters such as soil structure and humus morphology.Le recours à des épandages d'amendements calco-magnésiens dans les forêts acidifiées peut représenter une alternative intéressante pour corriger l'acidification des sols et la perte d'éléments nutritifs engendrés par des décennies de dépôts atmosphériques acides. Dans ce contexte, les objectifs de cette thèse sont d'évaluer les effets d'amendements calco-magnésiens sur (i) la diversité taxonomique et la structure des communautés des macroinvertébrés de sol forestier et sur (ii) deux processus fonctionnels associés notamment à l'activité des vers de terre, tels que la structuration du sol et l'évolution des humus. Au cours de nos travaux, trois sites localisés dans les Vosges (nord-est, France) ont été étudiés : deux massifs forestiers (sur grès et granite) en moyenne montagne, ayant fait l'objet d'amendements aériens en 2003 et la forêt domaniale de Humont située dans les collines sous-vosgiennes, où des amendements en 1991 et 2008 ont été réalisés. Les résultats montrent que 4 ans après amendement sur les bassins versants en moyenne montagne, l'abondance totale de la communauté de macrofaune a diminué, alors que les richesses spécifiques sont similaires. Cependant, la composition des communautés diffère avec moins de 50 % d'espèces communes aux sites amendés et témoins. Une diminution de l'abondance des prédateurs a également été observée alors que la plupart des détritivores ont été favorisés par l'amendement. Les études in vitro montrent également son effet positif sur les activités de structuration du sol par les vers de terre (production de turricules et construction de galeries). En forêt de Humont, les amendements ont eu un effet majeur à moyen terme (4 ans) et à long terme (20 ans) sur la population d'Aporrectodea velox, espèce endémique des Vosges. De part sa biomasse importante, cette augmentation de densité favorise l'amélioration des caractéristiques physico-chimiques du sol forestier tels que la structuration des sols et la morphologie des humus

The Way Soil Organisms Look Can Help Us Understand Their Importance. Frontiers for young minds.

International audienceThere is a multitude of life forms on our planet. This is especially true under our feet, in the soil. Earthworms, spiders, and millipedes are only a few examples of the vast number of soil organisms. Once you look what lives in soils, you realize the tremendous diversity of shapes and colors. But what if we take the time to describe all their characteristics: color, size, shape, number of legs, type of wings, lifespan, and climate preferences? All these characteristics, called traits, help us to understand what types of organisms can be found in a particular ecosystem, what they feed on, and how far they can travel. Scientists use this information to understand the different roles of organisms in soils, and to restore degraded soils. Analyzing traits can reveal the importance of soil organisms and the fundamental roles they play for human societies

Assessment of derelict soil quality: Abiotic, biotic and functional approaches

International audienceThe intensification and subsequent closing down of industrial activities during the last century has left behind large surfaces of derelict lands. Derelict soils have low fertility, can be contaminated, and many of them remain unused. However, with the increasing demand of soil surfaces, they might be considered as a resource, for example for non-food biomass production. The study of their physico-chemical properties and of their biodiversity and biological activity may provide indications for their potential re-use. The objective of our study was to investigate the quality of six derelict soils, considering abiotic, biotic, and functional parameters. We studied (i) the soil bacteria, fungi, meso- and macro-fauna and plant communities of six different derelict soils (two from coking plants, one from a settling pond, two constructed ones made from different substrates and remediated soil, and an inert waste storage one), and (ii) their decomposition function based on the decomposer trophic network, enzyme activities, mineralization activity, and organic pollutant degradation. Biodiversity levels in these soils were high, but all biotic parameters, except the mycorrhizal colonization level, discriminated them. Multivariate analysis showed that biotic parameters co-varied more with fertility proxies than with soil contamination parameters. Similarly, functional parameters significantly co-varied with abiotic parameters. Among functional parameters, macro-decomposer proportion, enzyme activity, average mineralization capacity, and microbial polycyclic aromatic hydrocarbon degraders were useful to discriminate the soils. We assessed their quality by combining abiotic, biotic, and functional parameters: the compost-amended constructed soil displayed the highest quality, while the settling pond soil and the contaminated constructed soil displayed the lowest. Although differences among the soils were highlighted, this study shows that derelict soils may provide a biodiversity ecosystem service and are functional for decomposition

Biodiversité et fonctionnement d’un Technosol construit utilisé dans la restauration de friches industrielles : principaux résultats issus du programme Biotechnosol.

Biodiversité et fonctionnement d’un Technosol construit utilisé dans la restauration de friches industrielles : principaux résultats issus du programme Biotechnosol.. 3èmes rencontres nationales de la Recherche sur les sites et sols pollués, journées techniques nationale

Functional structure and composition of Collembola and soil macrofauna communities depend on abiotic parameters in derelict soils

International audienceIn the last decades, anthropogenic disturbances have altered the ability of soils to provide diverse functions. Certain anthropogenic soils, with a low fertility level and often contaminated, ended up underused and derelict. Although derelict for humans, these soils may be refuges for biodiversity, but their biological functioning remains poorly understood. To this end, a trait-based approach of soil invertebrate communities might be an effective predictor of ecosystem state. The present work aims to highlight the in situ links between the abiotic characteristics of derelict soils and the taxonomic and functional structure and composition (through a trait-based approach) of macrofauna and Collembola communities inhabiting these soils. We studied 6 different derelict soils: two soils from coking plants, one soil from a settling pond, two constructed soils, and an inert waste storage soil. We measured fifteen abiotic soil parameters that inform on fertility and contamination. We took into account sixteen traits and ecological preferences to characterize the functional structure and composition of Collembola and macrofauna communities. Soil fertility (organic matter content, C:N ratio, P, Ca and Mg concentrations, cation-exchange capacity, and clay content) and moderate contamination (Pb, Cd, Zn, and PAH concentrations) altered the taxonomic and functional composition of Collembola and macrofauna communities by selecting traits such as body length, pigmentation, vertical distribution, diet type, and habitat preference. Compost-amended constructed soil properties selected taxonomic and functional community composition of slightly disturbed soil. In contrast, metal-contaminated constructed soil harbored a higher proportion of Collembola displaying the traits and ecological preferences of instable ecosystems. The study of functional profiles of Collembola and macrofauna communities in the derelict soils evidenced that they support different communities with more or less wide functional potential. It underlines the interest of multiple biotic component studies to reach a better ecosystem description

Colonization of a constructed Technosol by soil macro-invertebrates

Colonization of a constructed Technosol by soil macro-invertebrates . First Global Soil Biodiversity Conferenc

Modélisation multi-échelle de l'activité biologique des sols Prise en compte de l’hétérogénéité spatiale des ressources organiques. Questions scientifiques et état des lieux

Modélisation multi-échelle de l'activité biologique des sols Prise en compte de l’hétérogénéité spatiale des ressources organiques. Questions scientifiques et état des lieux. Modélisation multi-échelle de l'activité biologique des sols : prise en compte de l’hétérogénéité spatiale des ressources organique

Early colonisation of constructed technosols by macro-invertebrates

Purpose: Anthropogenic activities lead to soil degradation and loss of biodiversity, but also contribute to the creation of novel ecosystems. Pedological engineering aims at constructing Technosols with wastes and by-products to reclaim derelict sites and to restore physico-chemical functions. Materials and methods: The biological (dynamics of soil and epigeic macroinvertebrate assemblages) and physical (chemical and physical fertility) properties have been studied in two constructed Technosols under grassland during four years after their implementation. Results and discussion: The soils exhibited a moderate chemical fertility (high organic matter and calcium carbonate contents, low nitrogen content) and a good physical fertility that only slightly evolved over the monitored period. Macro-invertebrates have colonized these soils. This colonization was characterized by an increasing number of individuals and species over time. The diversity and abundance values fell within those quoted in the literature for similar natural soils. Epigeic invertebrates presented a succession, indirectly linked to changes in soil parameters. No succession was recorded for soil invertebrates. However, the proportion of soil detritivores, an important functional group for soil evolution, grew consistently. Questions about soil invertebrates functional complementarity/redundancy emerge in such artificially created ecosystem. Conclusions: The constructed Technosol, on which a meadow was sown and well-established after 4 years, can host numerous soil invertebrates. In addition, an increase in diversity was monitored throughout the duration of the study

Population-level consequences of spatially heterogeneous exposure to heavy metals in soil: An individual-based model of springtails

Contamination of soil with toxic heavy metals poses a major threat to the environment and human health. Anthropogenic sources include smelting of ores, municipal wastes, fertilizers, and pesticides. In assessing soil quality and the environmental and ecological risk of contamination with heavy metals, often homogeneous contamination of the soil is assumed. However, soils are very heterogeneous environments. Consequently, both contamination and the response of soil organisms can be assumed to be heterogeneous. This might have consequences for the exposure of soil organisms and for the extrapolation of risk from the individual to the population level. Therefore, to explore how soil contamination of different spatial heterogeneity affects population dynamics of soil invertebrates, we developed a spatially explicit individual-based model of the springtail, Folsomia candida, a standard test species for ecotoxicological risk assessment. In the model, individuals were assumed to sense and avoid contaminated habitat with a certain probability that depends on contamination level. Avoidance of contaminated areas thus influenced the individuals' movement and feeding, their exposure, and in turn all other biological processes underlying population dynamics. Model rules and parameters were based on data from the literature, or were determined via pattern-oriented modelling. The model correctly predicted several patterns that were not used for model design and calibration. Simulation results showed that the ability of the individuals to detect and avoid the toxicant, combined with the presence of clean habitat patches which act as "refuges", made equilibrium population size due to toxic effects less sensitive to increases in toxicant concentration. Additionally, the level of heterogeneity among patches of soil (i.e. the difference in concentration) was important: at the same average concentration, a homogeneously contaminated scenario was the least favourable habitat, while higher levels of heterogeneity corresponded to higher population growth rate and equilibrium size. Our model can thus be used as a tool for extrapolating from short-term effects at the individual level to long-term effects at the population level under more realistic conditions. It can thus be used to develop and extrapolate from standard ecotoxicological tests in the laboratory to ecological risk assessments