Soil invertebrates are assumed to play a major role in ecosystem dynamics, since they are involved in soil functioning. Functional traits represent one of the main opportunities to bring new insights ...into the understanding of soil invertebrate responses to environmental changes. They are properties of individuals which govern their responses to their environment. As no clear conceptual overview of soil invertebrate trait definitions is available, we first stress that previously-described concepts of trait are applicable to soil invertebrate ecology after minor modification, as for instance the inclusion of behavioural traits. A decade of literature on the use of traits for assessing the effects of the environment on soil invertebrates is then reviewed. Trait-based approaches may improve the understanding of soil invertebrate responses to environmental changes as they help to establish relationships between environmental changes and soil invertebrates. Very many of the articles are dedicated to the effect of one kind of stress at limited spatial scales. Underlying mechanisms of assembly rules were sometimes assessed. The patterns described seemed to be similar to those described for other research fields (e.g. plants). The literature suggests that trait-based approaches have not been reliable over eco-regions. Nevertheless, current work gives some insights into which traits might be more useful than others to respond to a particular kind of environmental change. This paper also highlights methodological advantages and drawbacks. First, trait-based approaches provide complementary information to taxonomic ones. However the literature does not allow us to differentiate between trait-based approaches and the use of a priori functional groups. It also reveals methodological shortcomings. For instance, the ambiguity of the trait names can impede data gathering, or the use of traits at a species level, which can hinder scientific interpretation as intra-specific variability is not taken into account and may lead to some biases. To overcome these shortcomings, the last part aims at proposing some solutions and prospects. It concerns notably the development of a trait database and a thesaurus to improve data management.
Man nimmt an, dass wirbellose Bodentiere eine wichtige Rolle bei der Ökosystemdynamik spielen, da sie am Funktionieren der Böden beteiligt sind. Funktionelle Merkmale bilden eine der wichtigsten Möglichkeiten für ein neues Verständnis der Reaktion von Bodenwirbellosen auf Umweltänderungen. Es handelt sich um Eigenschaften von Individuen, die deren Reaktion auf die Umwelt bestimmen. Da es keinen klaren konzeptionellen Überblick über die Merkmalsdefinitionen für Bodenwirbellose gibt, betonen wir zunächst, dass existierende Konzepte nach geringen Modifikationen auf die Ökologie von Bodenwirbellosen anwendbar sind, wie z.B. das Einbeziehen von Verhaltensmerkmalen. Anschließend betrachten wir ein Jahrzehnt der Literatur zum Gebrauch von Merkmalen bei der Abschätzung der Effekte der Umwelt auf Bodenwirbellose. Merkmalsbasierte Ansätze können unser Verständnis der Reaktionen von Bodenwirbellosen auf Umweltänderungen verbessern, da sie helfen, Beziehungen zwischen Umweltänderungen und Bodenwirbellosen zu etablieren. Sehr viele der Artikel widmen sich dem Effekt eines Stressfaktors auf begrenzten räumlichen Skalen. Die zugrundeliegenden Mechanismen von Vergemeinschaftungsregeln wurden manchmal bestimmt. Die beschriebenen Muster scheinen denen von anderen Forschungsgebieten (z.B. Pflanzen) ähnlich zu sein. Die Literatur legt nahe, dass merkmalsbasierte Ansätze über Ökoregionen hinweg nicht zuverlässig sind. Nichtsdestotrotz lassen aktuelle Arbeiten erkennen, welche Merkmale nützlicher als andere sein könnten, um auf spezielle Umweltveränderungen zu reagieren. Diese Arbeit stellt auch methodische Vor- und Nachteile heraus. Zuerst liefern merkmalsbasierte Ansätze Informationen, die taxonomische ergänzen. Indessen erlaubt uns die Literatur nicht, zwischen merkmalsbasierten Ansätzen und dem Gebrauch von a-priori definierten funktionellen Gruppen zu unterscheiden. Sie zeigt auch methodische Unzulänglichkeiten. So kann z.B. die Mehrdeutigkeit von Merkmalsbezeichungen das Sammeln von Daten behindern, oder der Gebrauch von Merkmalen auf der Artebene, der die wissenschaftliche Interpretation erschweren kann, da die intraspezifische Variabilität nicht berücksichtigt wird und zu gewissen Verzerrungen führen kann. Um diese Unzulänglichkeiten zu überwinden, hat der letzte Teil zum Ziel, einige Lösungen und Ausblicke vorzuschlagen. Dies betrifft namentlich die Entwicklung einer Merkmalsdatenbank und eines Thesaurus’ um die Datenverwaltung zu verbessern.
Soil invertebrates are known to be much involved in soil behaviour and therefore in the provision of ecosystem services. Functional trait-based approaches are methodologies which can be used to ...understand soil invertebrates' responses to their environment. They (i) improve the predictions and (ii) are less dependent on space and time. The way traits have been used recently has led to misunderstandings in the integration and interpretation of data. Trait semantics are especially concerned. The aim of this paper is to propose a thesaurus for soil invertebrate trait-based approaches. T-SITA, an Internet platform, is the first initiative to deal with the semantics of traits and ecological preferences for soil invertebrates. It reflects the agreement of a scientific expert community to fix semantic properties (e.g. definition) of approximately 100 traits and ecological preferences. In addition, T-SITA has been successfully linked with a fully operational database of soil invertebrate traits. Such a link enhances data integration and improves the scientific integrity of data.
Dans le contexte du développement des sciences et recherches participatives (SRP), de plus en plus d’initiatives sur les sols ont été engagées ces dernières années. Les sols sont des objets ...particulièrement intéressants pour les SRP car, en tant qu’écosystème en interface directe avec les hommes et d’autres écosystèmes, ils sont affectés par les activités humaines et ils sont des leviers de transformation, que ce soit du point de vue de l’agroécologie, de la biodiversité, de l’alimentation ou du climat. Cet article présente : i) les résultats d’une enquête réalisée auprès de la vingtaine de porteurs de projets identifiés en France, une analyse des propriétés et contextes ciblés ainsi que du niveau d’association des acteurs de la recherche et de la société ; ii) les enseignements d’un colloque rassemblant les acteurs des projets de SRP sur les sols, notamment à propos des attentes, des productions pour la recherche et la société, des difficultés et pépites, des mutualisations possibles. Ce colloque a rassemblé une centaine de personnes et a jeté les bases d’une mise en réseau national des acteurs concernés.
Along with the development of citizen sciences, an increasing number of initiatives concerning soils are emerging. Soils are key components of ecosystems and original objects for citizen sciences since they integrate the multiple impacts of human activities (agroecology, biodiversity, food, climate). This article presents an analysis of 20 on-going projects in France. It is based on a questionnaire circulated to the project leaders, regarding i) properties, use context and co-building processes between the actors of research and of society, ii) lessons learned from a conference associating the actors involved in these projects, on the needs, outputs for research and for society, difficulties and successes, and potential pooling between projects. This first conference on soil citizen sciences, which gathered some one hundred participants, may hopefully boost exchanges between projects and lead to developing a national network of actors concerned.
•Three different humus systems were found on a former coking plant area.•Technogenic parent material was the main factor driving humus system formation.•The presence of zoOH horizon was not ...influenced by the litter type.•Organic horizon chemical properties depended on both litter and soil substrate.•zoOH horizon improved Technosol humipedon’s chemical quality.
The study of humus systems provides a lot of information on soil ecological functioning, such as fauna functional community, soil nutrient status, organic matter decomposition, and microbial food web. Technosols have highly heterogeneous physicochemical properties and so far, their humus systems are poorly described and the mechanisms behind their formation are still largely to be studied. In order to fill this knowledge gap, this study was conducted to get better understanding of the factors involved in the development of different Technosols humus system after brownfield rehabilitation. Our sampling strategy followed a pollution diagnostic report and allowed to cope with the spatial heterogeneity of the studied area. We studied 24 soil profiles and identified 3 different humus systems on two different rehabilitation substrates: 7 Mull, 3 Amphi and 14 Techno-moder. Our results showed that the development of zoOH horizon resulted from the nature of underlying horizons but not from the main litter type. On Techno-moder, the accumulation of organic matter in the form of fecal pellets as a zoOH horizon resulted in an increase of 130% of nitrogen on soil surface. Contrary to what was expected, we did not find a threshold of heavy metals leading to the formation of zoOH horizon, with highest lead concentration found in the A horizon of Mull systems. Transmission electron microscopy (TEM) analysis showed that neoformed organic matter is biochemically stabilized as condensed polyphenols and melanized hyphae. EDX analysis revealed that such ultrastructures are associated with Ca and Zn that may explain their stability on the Technosols surface. Development of zoOH horizon on Technosols built from coking plant by-products allowed to improve soil surface chemical and biological properties. The evolution of the humus systems as a result of vegetation succession and microbial community composition should be further studied to specify the mechanisms involved in Technosols humus system dynamics.
Anthropic activities such as mining, resource extraction or transformation profoundly modify ecosystems and may lead to Technosol formation. Post-industrial areas are examples of potentially degraded ...lands, due to soil contamination with metals or organic pollutants, as well as soil structure damage. Soil biodiversity being closely involved in many soil functions such as organic matter decomposition, formation and stabilization of soil structure, the recovery of degraded soil functions partly depends on soil fauna colonization. However, the relationship between Technosol abiotic parameters and soil fauna colonization is still to be disentangled. In an attempt to fill this gap, we studied a former coking plant area in north-eastern France, composed of Technosols resulting from coking plant embankments or thermally-treated industrial soils and compared them with two local soils considered as references. We hypothesized that the taxonomic and trophic diversity of Technosol-dwelling invertebrates would be more diverse and abundant in the soils with the higher soil physico-chemical quality (i.e higher fertility and lower pollutions levels). To test this hypothesis, we studied four Technosols that were settled following two different rehabilitation strategies within the same post-industrial area and we compared them with two local soils of reference using nested ANOVAs as well as multivariate analyses of soil abiotic parameters and soil fauna community indices, both within the soil and on its surface.
The results on physico-chemical analyses showed that the substrates used for Technosol rehabilitation were impoverished in clay content when compared with local soils of reference (4.1 to 7.8-fold) and enriched in sandy materials. The use of coking plant by-products for Technosol implementation have led to poor chemical quality, with low nutrient content but high organic carbon content (41 to 51%) resulting from the use of coal and correlated with the higher lead concentration in the area. The use of thermally-treated industrial soil has led to more fertile Technosols with significantly lower lead content. Meso and macrofauna densities did not vary significantly between the Technosols and the local reference soils. Both Technosol-dwelling fauna trophic and taxonomic community compositions were impacted by the rehabilitation strategy. Few to no earthworms were found in Technosols (mean up to 16 ind.m−2) compared to the local soils of reference (mean of 118.4 and 201.6 ind.m−2). Conversely, Technosols resulting from coking plant embankments and thermally-treated industrial soils were dominated by epigeic soil fauna with an intense activity of soil surface macro-saprophages and micro-arthropods, as well as Formicidae. Our results suggest that the use of technogenic elements in the rehabilitation of post-industrial area led to the development of specific soil invertebrate communities, different from the reference. The gap between the high level of activity of epigeic organisms that we found on Technosols and the low trophic diversity of the litter and soil-dwelling communities suggest that the soil fauna community on a former coking plant is driven rather by soil physico-chemical properties than by colonization constraints.
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•Studied Technosols had low nutrients and coarse texture compare to local references.•Fauna diversity and soil abiotic parameters co-varied strongly.•Almost no earthworms were found in the Technosols compared to other faunal taxa.•The nature of the substrate used appear as a driver of the edaphic fauna community.
The 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.
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•Abiotic, biotic, and functional parameters of six derelict soils were compared.•Microbial, faunal (meso- and macrofauna) and plant components were studied.•A high biodiversity level and decomposition functions were observed in the derelict soils.•A strong co-variation between abiotic-biotic and abiotic-functional parameters was found.•Derelict soils may provide biodiversity ecosystem service and be a resource for biomass production.
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•Micromorphology of Technosols’ humipedons was studied on a former coking plant area.•A new humus form had developed on the highly anthropized area.•The term “techno-moder” is ...proposed to classify this new humus form.•Faunal feces were accumulated on a technogenic horizons in absence of earthworms.•Humipedon characteristics could be considered as footprints of anthropic activity.
Human impact on soil systems is now widely acknowledged. “Technosols” appeared in soil classification only a decade ago and the notion of “techno humus system” has emerged even more recently. Yet the variety of humus forms that could develop on Technosol remains largely unknown. To contribute to filling this knowledge gap, we studied the humus form developing on two Technosols resulting from the activity of a former coking plant and compared it with one developed on a Cambisol as a reference for the area. We used field description and micromorphology on thin sections coupled with a point-and-count method to precisely describe the surface of the humipedons of the area studied. A total of 13,841 counts and identifications were performed on 11 thin sections and spread into 17 fabric units. Micromorphology on thin soil sections revealed that epi-saprophagous organisms transformed most of the neo-formed organic matter on the Technosols studied, leading to an accumulation of feces on the surface of the humipedon. Our results suggested that the humus form developing on the Technosols was similar to a moder and exhibited the same ectorganic horizons (OL, OF, zOH), whilst overlaying a technogenic one composed mostly of coal fragments. We would like to propose the term “techno-moder” for this new humus form, developing in the absence of an A horizon. On the other hand, micromorphology allowed us to classify the humus form developed on the Cambisol as a eumull containing anthropic coal by-products. Specification of the humus form developing on such soils could represent a promising way to specify pedological processes such as organic matter decomposition, soil aggregation and also to enrich the humus form classification on Technosols.
•Collembola and macrofauna communities from derelict soils were characterized.•Links between fauna community composition and soil characteristics were studied.•Fertility and contamination altered ...invertebrate community structure and composition.•Compost-amended constructed soil selected typical slightly disturbed soil species.•Collembola species traits in contaminated and constructed soil were typical of instable ecosystems.
In 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.
Ecological engineering of degraded ecosystems often manipulates plants, with positive outcomes for their restoration or ecosystem services production. The importance of soil biota for successional ...plant communities has prompted consideration of direct inoculation (active) or attraction (passive) of soil organisms as a relevant restoration strategy. However, few attempts have manipulated soil invertebrates as part of nature based solutions for ecosystem restoration, despite their major role in many soil ecological processes and in plant-soil feedback processes. In addition, while ecological restoration and ecological engineering approaches successfully incorporate plant traits, soil invertebrate traits remain underused. Exploiting the functional diversity of soil communities by adopting a trait-based approach could enhance restoration of soil chemical, biological and physical properties. Here, we conduct a narrative review and identify a set of soil invertebrate functional traits with great potential in ecosystem restoration. We focus on traits related to four main ecological functions that are often at the core of restoration plans: nutrient cycling and carbon cycling, pollutant detoxification, soil structure arrangement, and biological control agent by prey/pest regulation. This paper further proposes guidelines for stakeholders that need to be addressed to successfully integrate soil organism traits into ecological engineering. Finally, we highlight main knowledge gaps and limitations currently impeding the use of soil invertebrate traits in ecological engineering, and identify avenues for future research. We especially bring out (i) that few studies still use soil invertebrates in restoration, so even fewer are based on traits, (ii) a lack of data about soil invertebrate species role in ecosystems, (iii) a lack of data about attributes from specific traits and groups in existing soil functional trait databases, (iv) the complex relationships between functions and traits and (v) that future studies are needed to demonstrate the benefits of such trait-based approaches compared to approaches relying on emblematic species.
Although fires are common disturbances in North American forests, the extent to which soil invertebrate assemblages recover from burning remains unclear. Here, we examine long-term (14- to 101-yr) ...recoveries of soil invertebrate communities from common cut and burn treatments conducted at 6 to 26-yr intervals since 1911 in a deciduous forest in the upper Great Lakes region (USA). We characterize soil surface macro-invertebrate communities during both fall and spring across a long-term, experimental fire chronosequence to characterize invertebrate community recovery at decadal time-scales and community changes between seasons. We posited that changes in invertebrate community structure might, in turn, impact decomposition process. We sampled active organisms at the soil surface using pitfall traps. We described understory vegetation, measured soil properties, and conducted a 4-year litter bag study with big-toothed aspen leaves (Populus grandidentata). Invertebrate community responses followed a habitat accommodation model of succession showing that invertebrate succession is dependent on the soil surface properties. The fall and spring measures revealed that the densities of active invertebrates were highest 101 years after fire. For a given pair of stands, a pattern of sharing higher percentage of taxa was denoted when stands were of similar age. Some species such as the beetle Stelidota octomaculata appeared to be indicator of the chronosequence succession stage because it tracks the successional increase of Quercus and acorn production at the study site. We also found a significant positive correlation between leaf decomposition of soil macrofaunal accessible leaves and millipedes density across the chronosequence. We show that vegetation cover changes and related shifts in habitat structure occurring during post-fire succession are important in shaping communities assemblages. This finding highlights the importance of simultaneously considering abiotic-biotic factors together with above- and belowground measurements to better characterize controls on successional community dynamics after disturbance.
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•Soil invertebrate assemblage recovery from forest cutting and burning was studied.•We used a 14- to 101-yr fire chronosequence in northern Michigan (USA).•Seasonal and successional decadal-scale changes in soil communities were quantified.•Vegetation cover changes shape the taxonomic and functional compositions of soil communities.•Changes in soil community compositions impact ecosystem process such as decomposition.
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