Environmental and ecological degradation can be monitored by biological indicators such as plants, yet little research has been done using subterranean organisms such as collembola, especially in ...cities. Collembola, a soil fauna group, can be used to assess soil quality and to decipher assembly rules of soil organisms in cities. Here, we review 75 articles on soil collembola in an urban context. We found that soil properties and landscape characteristics influenced soil communities. There is a need for more connectivity between green urban spaces to allow the dispersion of collembola. Little information is available on the assembly of collembola communities, on biotic interactions and on dynamics of colonisation.
Soil trace metal concentrations (e.g., cadmium, copper, lead, zinc) in vegetable gardens have often been observed as exceeding the geochemical background levels. These metals are a threat both to ...soil and plant functioning and to human health through consumption of contaminated vegetables. We used a mass balance-based model to predict the four metal (Cd, Cu, Pb, Zn) concentrations in soils after a century’s cultivation for 104 urban vegetable gardens, located in three French metropolises, Nancy, Nantes, and Marseille, based on a survey of gardening practices. If current gardening practices are maintained, an increase in soil Cd (35% on average), Cu (183%), and Zn (27%) contents should occur after a century. Soil Pb concentration should not vary consistently. Organic amendments are the major source of Cd, Pb, and Zn, followed by chemical fertilizer while fungicide application is the major source of Cu. Cessation of chemical fertilizer use would only slightly reduce the accumulation of the four metals. The solubility of the four metals would decrease significantly after a century, when pH increases by one unit. A liming practice of acidic soils should therefore be a feasible way to prevent any increase in the metal mobility and bioavailability.
Abstract
In view of the demographic revolution and the rapid development of urban environments, the installation of green roofs could be a tool to ensure human well-being (e.g. heat island reduction, ...rainwater management), or to increase urban biodiversity. However, the relationships between biodiversity and green roofs are not yet clear and little research has looked into this. We therefore reviewed studies on the overall biodiversity of green roofs. Our review has shown that there is a lack of knowledge of the biodiversity of green roofs, with recent consideration. We highlighted the importance of green roof contribution, in maintaining urban biodiversity through three lines of research: characterization, modes of use and design. Furthermore, we found that there were very few studies on soil biodiversity on this topic. We concluded that green roof construction guidelines should integrate soil communities into their design and aim to be heterogeneous at roof and landscape level. Future research should focus on the diversification and redundancy of rooftop conditions in the urban matrix. This would increase the area of green habitats and the success of species dispersal in cities.
Green infrastructures play a key role in the functionality and resilience of urban ecosystems. The physical, including thickness, chemical and biological properties of the Technosols of green ...infrastructures on rooftops are highly variable, leading to more or less favourable conditions for soil biodiversity. The aim of this study was to investigate the abundance and diversity of bacteria, fungi, nematodes, collembola and plants communities in relation with abiotic parameters of Technosols on 12 productive and extensive green roofs of the Paris region (France).
Results showed that green roofs harboured a high level of abundance and diversity from microorganisms to micro and mesofauna. Microbial biomass ranged between 16.3 and 419.8 μg DNA g−1, with a predominance of bacteria, nematodes represented 820–60,700 individuals per kg of soil and between 1000 and 60,700 collembolan were present per m2 of soil. A total of 13,986 bacterial OTU (Operational Taxonomic Unit), 33,559 fungal OTU, 47 Collembola species, 28 nematodes families, 16 cultivated plant species and 48 spontaneous plant species was identified on all the green roofs studied. Microbial, animals and plants communities were significantly different between the two types of green roofs. Productive and extensive rooftops represent contrasted habitats, which can strongly influence the soil biota. Any voluntary action to enhance soil biodiversity in cities would need to take-into-account both soil properties and the landscape around.
Display omitted
•Soil biodiversity and plants communities have been investigated on 12 productive and extensive green roofs•Green roofs harbour higher abundances and diversity of Collembola than forest or agricultural soils•Green roofs harbour higher microbial biomasses than forest or agricultural soils•Only productive green roofs harbour higher abundances of nematodes than forest or agricultural soils•Productive and extensive rooftops present contrasted communities (abundance and diversity)
Purpose
Urban soil contamination by heavy metals is one of the foremost challenges for urban soil quality, especially in the urban agriculture context. Urban gardening is a common practice in many ...industrialized and developing countries. How sources of soil contamination relate to inputs and influence the heavy metal content in soils, however, is not established yet.
Materials and methods
This study aims to assess the potential of pesticide applications (such as Bordeaux mixture) on soil quality. A set of 104 allotment gardens was selected in three cities in France, and topsoil was sampled and analyzed.
Results and discussion
The four most abundant metals in urban vegetable garden topsoils were Zn, Pb, Cu, and Cr. The past and/or present industrial and urban activities are not the only cause of the metal contamination in urban vegetable garden soils. Gardens, where pesticides such as the Bordeaux mixture are being used showed significantly higher total Cu values in soils (78 mg kg
−1
compared with 49 mg kg
−1
for untreated gardens).
Conclusions
Even though the risk of metal contamination through vegetable consumption is usually considered low, we clearly identified indicators of anthropogenic Cd, Cu, Pb, and Zn pollution due to pesticides inputs. This link was particularly strong between the use of Bordeaux mixture and increases Cu levels.
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.
Investigating the functional facet of biodiversity provides ecologists with a deeper understanding of community assembly and ecosystem processes, from local to biogeographical scales. A central ...assumption in functional ecology is that interspecific trait variability is higher than intraspecific variability. The “stable species hierarchy” hypothesis states that for similar species found in different environmental conditions, their species trait ranking is conserved. In this study, we applied this trait hierarchy concept prevalent in plant ecology to the growing field of soil functional ecology, for which newly developed trait databases are being increasingly used. However, to date there have been few attempts to test for patterns of intraspecific trait variability (ITV) in these databases.
We thus aimed to characterize how such patterns might influence (a) a species hierarchy based on trait values and (b) the conclusions of a trait‐based analysis at a community level. To examine this, we used Collembola body size data (extracted from the BETSI database) as model trait. The source consisted of four regional trait datasets (Poland, Scandinavia, Spain and UK) and one dataset for which species traits are defined at a continental (European) scale.
We found that, firstly, species were consistently ranked in all the trait datasets, although slight differences were observed between continental and northern European (i.e. Scandinavia and UK) trait datasets. In the two northern datasets, body size was higher (ca. 10%), indicating an intraspecific body size gradient from temperate to colder northern regions that we assumed could be explained by latitudinal patterns.
Secondly, using selected published species abundance matrices (from experimental studies), we calculated the community‐weighted mean body size using various trait datasets. The findings showed that the slight discrepancies observed between trait datasets can lead to different conclusions.
This work confirms that properly defining the extent of ITV in databases is of primary importance to ensure robust conclusions. This is particularly important for databases hosting large‐scale data that might be influenced by biogeographical patterns as latitudinal gradients. We recommend using a local regional trait dataset when available or, if not, a continental trait dataset. As trait databases are now commonly used tools for performing trait‐based analyses, it is crucial to carefully select the data used to make inferences.
A plain language summary is available for this article.
Plain Language Summary
Urban allotment gardens (AGs) provide a unique combination of productive and recreational spaces for the inhabitants of European cities. Although the reasons behind the decision to have a plot, as ...well as the mode of use and gardening practices, are well recognised in the literature, these issues are mainly considered in relation to particular case studies within a single country. The regional diversity of European allotment gardens is still poorly understood, however. This knowledge gap became an incentive for us to carry out the present study. The research was conducted in seven countries: Austria, Estonia, Germany, France, Portugal, Poland and the UK. Surveys were used to assess the motivations of users regarding plot uses and gardening practices. Information was also collected during desk research and study visits, making use of available statistical data. Allotment gardens in Europe are currently very diverse, and vary depending on the historical, legal, economic and social conditions of a given country, and also as determined by geographical location. Three main types of plots were distinguished, for: cultivation, recreation–cultivation, and cultivation–recreation. The recreational use of AGs has replaced their use for food production in countries with a long history of urban gardening. The only exception is the UK. In some countries, the production of food on an AG plot is still its main function; however, the motivations for this are related to better quality and taste (the UK), as well as the economic benefits of self-grown fruits and vegetables (Portugal, Estonia). Among the wide range of motivations for urban gardening in Europe, there is increasing emphasis on active recreation, contact with nature and quality food supply.
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.
•Classifying organisms has a wide use and a long history in ecology.•We provide a critical overview of the existing classifications used for soil fauna.•We propose semantic clarifications and ...alternatives to current practices.•We suggest a common framework to define classifications based on functional traits.
Classifying organisms has a wide use and a long history in ecology. However, the meaning of a ‘group of organisms’ and how to group organisms is still the subject of much theoretical and empirical work. Achieving this long quest requires simplifying the complexity of species niches for which relevant morphological, behavioural, biochemical or life-history traits are often used as relevant proxies. Soil fauna is highly diverse and many classifications have been proposed to synthesize both the response of soil organisms to their environment and their effect on soil functioning. Here, we provide a critical overview of the characteristics and limitations of the existing classifications in soil ecology, and propose clarifications and alternatives to current practices. We summarise the similarities and differences in how classifications have been created and used in soil ecology. We propose a harmonization of the current concepts by properly defining ‘guilds’, ‘functional groups’ and ‘trophic groups’ as subcategories of ‘ecological groups’, with different purposes and distinguishing criteria. Finally, based on these concepts, we suggest a common framework to define classifications based on functional traits that allows a better and unified understanding of changes in soil biodiversity and ecosystem functioning.
PDF
