2020 Issues

Anton Potapov, Bruno Bellini, Steven Chown, Louis Deharveng, Frans Janssens, Ľubomír Kováč, Natalia Kuznetsova, Jean-François Ponge, Mikhail Potapov, Pascal Querner, David Russell, Xin Sun, Feng Zhang & Matty Berg

Title: Towards a global synthesis of Collembola knowledge – challenges and potential solutions

Abstract
Collembola are among the most abundant and diverse soil microarthropods, which are found in almost all (semi)terrestrial environments and often serve as model organisms in empirical studies. Diverse data collected on the biology and ecology of Collembola over the last century are waiting for synthesis studies, while developing technologies may facilitate generation of new knowledge. Collembola research in 2020 is entering the stage of global synthesis and in this opinion paper we address the main challenges that the community of collembologists is facing on this avenue. We first discuss the present status and social context of Collembola taxonomy and the potential use of novel technologies to describe new species. We then focus on aspects of community ecology, reviewing the processes of dispersal, environmental and biotic filtering, from the spatial scale of microhabitat to the globe. We also discuss the involvement of Collembola in ecosystem processes and which proxies, such as functional traits, can be used to predict the functional roles of species. Finally, we provide recommendations on how we can improve community data collection by using standard methods and better data handling practices. We call for (1) integrating morphological descriptions with high-resolution photographs and genetic barcodes for species descriptions and developing of user friendly software and machine learning approaches to facilitate deposition of structured taxonomic knowledge on web platforms; (2) multiscale studies on biodiversity distribution and community processes, especially including dispersal mechanisms; (3) recording and sharing functional, not only morphological, trait data in controlled experiments and field surveys; (4) knowledge synthesis and meta-analysis studies on the topics of ecosystem roles of Collembola, conservation of its diversity, feeding behaviour, protection mechanisms and dispersal of different Collembola species, and effects of land use and climate change on collembolan communities; (5) joint efforts in covering the gaps in Collembola knowledge, especially in underexplored regions (predominantly tropics and subtropics) using standard methodologies; (6) data sharing and its integration in open structured databases. We believe that Collembola studies could make use of new technologies and ongoing changes in society. To facilitate the progress across these research topics by 2040, we have established #GlobalCollembola, a distributed-effort community-driven initiative that aims to provide open and global data on Collembola taxonomic and genetic diversity, abundance, traits and literature and to coordinate global efforts in covering the key knowledge gaps.

Keywords
springtails, taxonomy, macroecology, functional traits, #GlobalCollembola

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http://doi.org/10.25674/so92iss3pp161

Stefan Geisen, Enrique Lara, Edward A.D. Mitchell, Eckhard Völcker & Valentyna Krashevska

Title: Soil protist life matters!

Abstract
Soils host most biodiversity on Earth, with a major fraction of its taxonomic diversity still to be uncovered and most of its functional knowledge to be determined. Much focus has been – and still is – on bacteria, fungi and animals. Clearly, without any of those components, soils would not function as they do. However, the group that constitutes the bulk of eukaryotic diversity and plays a central role for soil functioning is missing: protists. As the main consumers of the microbiome, protists shape its composition and functioning. Other less known functions performed by protists may be equally important. Protists also include primary producers, decomposers, animal parasites and plant pathogens. We briefly review the many functions protists perform in soils and argue that soil biodiversity studies that ignore protists miss some potential mechanistic insight into the drivers of observed patterns. We highlight that the immense functional repertoire of protist affects virtually every soil process, from carbon cycling to primary production, including crop production. Therefore, we call for truly integrated biodiversity assessments including protists, without which the soil food-web and processes cannot reliably be understood: protists matter!

Keywords
Soil biodiversity, Microbiome, Protozoa, Soil food-web, Microfauna, Predator-prey interactions

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http://doi.org/10.25674/so92iss3pp189

Jean-David Moore

Title: No effect of liming on the Eastern Red-backed Salamander after 5 years

Abstract
Over the last decades, the application of calcitic materials to soil to restore the vigor of Sugar Maple (Acer saccharum Marsh) trees has increased in northeastern North America. However, few studies have evaluated how this treatment affects other ecosystem components, especially over several years. In Sugar Maple stands, the Eastern Red-backed Salamander (Plethodon cinereus Green, 1818) is one of the most abundant vertebrates and an important terrestrial species for key ecological processes. Because the species commonly serves as an indicator of forest disturbances, it is important to know how anthropogenic disturbances, such as soil liming, might affect it. The goal of this study was to evaluate the medium-term (5-year) effects of liming on body condition in a wild population of P. cinereus in Quebec, Canada. Lime (CaCO3) was spread by helicopter on a declining Sugar Maple forest growing on an acidic and base-poor soil. The results of this study, combined with those of previous published works, show that liming has no short- or medium-term effects on the body condition of the Eastern Red-backed Salamander. This study adds to those on other species in Europe and northeastern North America that report that liming has no major effect on amphibians when it is used as a treatment to restore acidified forest ecosystems. This should help foresters decide whether or not liming treatments are compatible with conservation, ecological, and management objectives.

Keywords
Amphibians, body condition, forest soil, Plethodon cinereus

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http://doi.org/10.25674/so92iss3pp197

Willi E.R. Xylander

Title: Society´s awareness for protection of soils, its biodiversity and function in 2030 – We need a more intrinsic approach

Abstract
Decades of efforts to achieve comprehensive and sustainable soil (biodiversity) protection resulted in a moderate to limited success. The ecological arguments – the extrinsic approach – are largely formulated and known. However, it is not possible to make them sufficiently heard as they stand against the interests of lobby groups. Therefore, in order to protect the soil, its functions and biocoenoses efficiently, I plead for an extended, intrinsic, centripetal approach, which includes physical-haptic, but also digital experience, transdisciplinary networks and the establishment of sympathizers for soil biodiversity. To this end, I name best practice examples from the past and present. For the development and establishment of this ‘strategy for a comprehensive sensitivity for soil (biodiversity) protection’ I expect a period of 10 years.

Keywords
soil biodiversity, conservation, touring exhibitions, science and art, story telling, virtual reality

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http://doi.org/10.25674/so92iss3pp203

Jeannette Mathews, Frank Glante, Michael Berger, Gabriele Broll, Uta Eser, Andreas Faensen-Thiebes, Norbert Feldwisch, Wilhelm König, Nikola Patzel, Rolf Sommer & Willi E.R. Xylander

Title: Soil and biodiversity – Demands on politics

Abstract
During the conference ‘Rediscovering the soil with Alexander von Humboldt. Soil and Biodiversity – Everything is connected with everything’ in Berlin on December 5, 2019, a political statement was prepared as a major result of the discussion. Many important German organisations for nature conservation and soil protection (Tab. 1) signed this political statement in the spring of 2020. A translated version of ‘Boden und Biodiversität – Forderungen an die Politik’ is presented here, as it addresses the German and the EU common agricultural and conservational policy.

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https://doi.org/10.25674/so92iss2pp95

Peter Dietrich, Simone Cesarz, Nico Eisenhauer & Christiane Roscher

Title: Effects of steam sterilization on soil abiotic and biotic properties

Abstract
Experiments under natural conditions are becoming increasingly important to investigate the impacts of global change on biodiversity and ecosystem functioning, but field experiments are not always feasible. Climate or biodiversity chamber experiments can be an alternative, which, however, require large amounts of soil substrate. If only low amounts of target soil are available, high quantities of background soil must be sterilized and inoculated with target soil. One of the commonly used methods to sterilize large amounts of background soil is steam sterilization, because it is simple, fast and cheap. However, there is a lack of knowledge, whether steam sterilization is an effective method to completely eliminate all organisms in the soil (in particular heat-resistant organisms) as well as if and how it alters soil abiotic conditions like nutrient concentrations. Therefore, we tested which organisms survived the sterilization treatment and if the effectiveness can be improved by repeated steam sterilization. Additionally, we checked whether steam sterilization changes soil pH, carbon and nutrient concentrations, and whether this is strengthened by a double sterilization treatment. To study this, we steam-sterilized 2 m3 sand-soil mix (1:4) for 150 min, stored it for 12 days at ambient temperature (for the germination of heat-resistant organisms) and repeated the sterilization procedure. We found a 27 % reduction in microbial biomass carbon after the first sterilization treatment and a 51 % reduction after the second sterilization treatment compared to untreated soil. Nematodes were almost completely eliminated (97 % after second treatment), while rotifers largely remained unchanged. Soil pH and plant-available phosphorus concentration increased after the first sterilization treatment (pH: from 7.44 to 7.79; phosphorus: +28 %). Phosphorus concentration increased further after the second sterilization treatment (+53 % compared to untreated soil), while pH remained unchanged (7.77). Plant-available potassium and total carbon concentrations decreased after the first treatment (potassium: -19 %; carbon: -5 %), while total carbon further decreased (-8 % compared to untreated soil) and potassium remained unchanged after the second treatment. Taken together, our study highlights that (single and double) steam-sterilization treatments were only partially effective, i.e. non-complete elimination of soil organisms, and additionally influenced soil properties. Nevertheless, steam sterilization is a fast and cost-effective alternative to other sterilization methods, especially when large amounts of soil substrate are needed. Therefore, if so, we recommend to use steam sterilization, but to sterilize the soil twice to significantly reduce the number of soil organisms, and further consider potential side effects, such as an increase in plant-available phosphorous concentration.

Keywords
microbial biomass, nematodes, plant-available phosphorus, plant-available potassium, soil biodiversity

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https://doi.org/10.25674/so92iss2pp99

Carlos Barreto, Matthias C. Rillig & Zoë Lindo

Title: Addition of polyester in soil affects litter decomposition rates but not microarthropod communities

Abstract
Microplastics are defined as plastic particles that are <5mm. Manufactured in the production of many commercial products, microplastics have become an environmental threat for many organisms. Microplastics can be highly abundant in soil, and given their size, can interact with soil microarthropods. But how microplastics affect soil-dwelling organisms (mites and collembolans) and their role in ecosystem services such as decomposition is largely unknown. We studied the effects of polypropylene and polyester microfibers of two different lengths (2–3mm and 5–6mm) on microarthropod communities and decomposition rates in a sandy soil. Microplastic addition showed no effects on soil microarthropod communities for the groups Oribatida (abundance and species richness), Prostigmata, Astigmata and Mesostigmata, Collembola, nor other invertebrates present in the soil samples (abundance). The addition of microplastics in the soil did affect litter decomposition rates for litterbags on the soil surface; higher mass loss (i.e. decomposition) was found in polyester treatments compared to control and polypropylene treatments, regardless of the length of the fibers. However, no significant differences were found on feeding rates measured by bait-lamina sticks. Permanova results for microarthropod community structure among treatments were not significant, although non-metric multidimensional scaling analysis (NMDS) found that communities were less similar to one another in polypropylene addition treatments compared to polyester addition and to control treatments. This study is the first to test the effects of microplastics on soil microarthropod communities, and we find no direct negative effects of microplastic addition.

Keywords
microplastics, litterbags, bait-lamina strip, Acari, soil organism

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https://doi.org/10.25674/so92iss2pp109

Helen R. P. Phillips, Léa Beaumelle, Nico Eisenhauer, Jes Hines & Linnea C. Smith

Title: Lessons from the WBF2020: extrinsic and intrinsic value of soil organisms

Abstract
Following our participation in the first World Biodiversity Forum in Davos, Switzerland, we provide a summary of the main themes of the conference, as well as an overview of the session that was focused on soil biodiversity. One of the main themes of the conference was the valuation of biodiversity and what contributes to the value of biodiversity. In this article we explore whether we should move away from the notion that we can only ‘sell’ soil biodiversity based on the function and services it provides, and rather shift towards valuing soil biodiversity based on its intrinsic value and our relationship with it.

Keywords
World Biodiversity Forum, ecosystem functions and services, intrinsic value, valuing soil biodiversity

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https://doi.org/10.25674/so92iss2pp121

Céline Pelosi, Gergely Boros, Folkert van Oort & Olaf Schmidt

Title: Soil Oligochaeta communities after 9 decades of continuous fertilization in a bare fallow experiment

Abstract
Mineral and organic fertilizers and amendments modify soil characteristics and impact beneficial soil organisms. However, conventional fertilizer experiments cannot separate impacts mediated through changes in crop productivity and through changes in soil chemical properties. We assessed populations of earthworms and enchytraeids (Oligochaeta, Annelida) in the surface horizons of a loess Luvisol of a world-unique long-term bare fallow experiment of INRAE (Versailles, France) to test the trophic and edaphic limits of existence for these soil taxa. Continuous annual applications since 1928 of 16 different treatments including nitrogen, phosphorus, potassium fertilizers but also basic (alkaline) and organic amendments, led to strongly diverging physical and chemical properties in the soil’s surface layer. The feeding activity of soil organisms was also assessed using the bait lamina method, assuming that lower bait consumption rates would be observed in treatments where fewer terrestrial Oligochaeta persist. We showed that compared to conventionally managed cultivated soils, both taxa were much less abundant in these extreme soil treatments, but enchytraeids were relatively more abundant than earthworms, ascribed to the enchytraeids’ higher tolerance to low pH soil conditions and a different feeding ecology. Most of the enchytraeid and earthworm individuals were found under horse manure inputs and basic amendments, suggesting that organic matter contents and/or pH would drive most of the Oligochaeta communities. Moreover, the bait-lamina feeding activity was significantly positively correlated with enchytraeid abundance. This study underlines the usefulness of historic long-term trials to improve knowledge on the ecology of soil organisms, and it presents an example of long-term soil biological resilience in highly degraded soils.

Keywords
Potworms, fertilizers, physico-chemical soil properties, long-term field experiments

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https://doi.org/10.25674/so92iss2pp129

Wilian Demetrio, Orlando Assis, Cintia C. Niva, Marie L. C. Bartz, Leocimara Paes, Guilherme Cardoso, Everaldo dos Santos, Márcia Marzagão, Herlon Nadolny, Klaus D. Sautter & George G. Brown

Title: Comparison of soil invertebrate communities in organic and conventional production systems in Southern Brazil

Abstract
Invertebrates play important functional roles in soils, affecting several essential ecosystem services. However, their populations are sensitive to disturbance, and are therefore often used as bioindicators of soil quality. Conservation agriculture covers extensive areas in Brazil, and organic production techniques have been rapidly spreading, but little is known regarding their impacts on belowground invertebrate communities. Thus, the present study evaluated the effects of different land-use and management systems on macro- and mesofauna communities in rural areas near Quitandinha, Southern Brazil. Samples were taken in a native forest (NF), organic (OH) and conventional horticulture farms (CH) and a conventional reduced tillage field (RT). Soil macrofauna and earthworms were collected by hand sorting, using the Tropical Soil Biology and Fertility (TSBF) method, and mesofauna were collected using a modified Berlese funnel apparatus. Enchytraeids were sampled using the standard ISO 23611-3 method. Six earthworm species were found, in the genera Glossoscolex and Amynthas as well as Ocnerodrilidae juveniles and an unidentified species. Four genera of enchytraeids were found, two of them cosmopolitan (Fridericia, Enchytraeus) and two native (Guaranidrilus, Hemienchytraeus). Soil tillage practices (in CH and OH) were associated with lower earthworm populations, while ants, spiders, ecosystem engineers and enchytraeids were more associated with organic fertilization and no pesticide use. Conventional systems (RT and CH) had lower macrofauna, enchytraeid and ant populations than NF and OH, and CH had the lowest richness of both macro- and mesofauna, as well as the lowest abundance of earthworms, spiders, fly larvae and “other” macro and mesofauna. Reduced tillage had higher earthworm and mite populations, while NF had the highest macrofauna and earthworm taxonomic richness and termite abundance. Reducing tillage in OH and CH may improve conditions for soil fauna, but further work is still needed to determine the best suite of management practices that promote soil fauna and their contributions to soil function and ecosystem services in these systems.

Keywords
macrofauna, mesofauna, earthworms, enchytraeids, soil management

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+ Supplementary data file

https://doi.org/10.25674/so92iss2pp143

Rüdiger M. Schmelz

Title: BOOK REVIEW

Enchytraeids of Hungary (Annelida, Clitellata, Enchytraeidae)

Abstract
by Klára Dózsa-Farkas, professor emeritus, Department of Systematic Zoology and Ecology of the Eötvös Loránd University, Budapest, Hungary

226 pp., 134 figure plates, 21 tables. ISBN: 978-963-489-069-0. Pedozoologica Hungarica No. 7, 2019. Ed.: Csaba Csuzdi. Publ.: the Dean of the Faculty of Science of Eötvös Loránd University.

Keywords
Enchytraeids of Hungary, monograph

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https://doi.org/10.25674/so92iss2pp159

Peter Decker, Bärbel Benz, Karsten Hannig, Birgit Hüther & Michael Hüther

Title: Obituary Dr Walter Hüther (1931-2019)

Abstract
Dr Walter Hüther, soil zoologist, entomologist and university lecturer, died on 11 May 2019, aged 87 years, in Bochum. Walter Hüther (Figs. 1 and 2) was born on 22 August 1931 in Homburg (Saarland), Germany, as the fourth of five children. He became interested in zoology already as a pupil, first at the elementary school and later at the grammar school for natural sciences in Zweibrücken, and this topic was to accompany him throughout his life.

Keywords Obituary

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DOI 10.25674/so92iss1pp1

Matthias Rillig

Title: Experimental tools for addressing effects of complex substance mixtures in soil
TECHNICAL COMMENT

Abstract
Pollution is one of the most important factors responsible for reductions in biodiversity and nature’s contribution to people (Díaz et al., 2019). Various environmental compartments, including soils, or individual target organism in the soil, are typically influenced not by single substances, but rather by a complex array of a wide range of compounds (Drakvik et al., 2020). These compounds, including an increasing number of manufactured chemicals, byproducts or compounds resulting from transformations in the environment, number in the hundreds of thousands. Addressing the impacts of such mixtures on soils and soil biota in experiments is important, but very challenging, as substances can occur in the environment in a virtually infinite number of different combinations.

Keywords
pollution, compound mixes, experimental design, ecotoxicology

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DOI 10.25674/so92iss1pp5

Raúl Ochoa-Hueso, Anita C. Risch, Scott L. Collins, Nico Eisenhauer & Wim H. van der Putten

Title: Ecosystem and biogeochemical coupling in terrestrial ecosystems under global change: A roadmap for synthesis and call for data
CALL FOR COLLABORATION

Abstract
Coupled ecosystems may offer a wider array of highly valuable ecosystem services. However, empirical evidence supporting the role of ecosystem coupling for the functioning of ecosystems and the mechanisms driving the coupling-functioning relationship is scarce. Moreover, global environmental change may decouple ecological interactions and biogeochemical cycles well before an overall degradation of ecosystems can be detected, yet the functional implications of this decoupling remains unresolved. Here, we introduce a collaborative call to carry out a synthesis of previously conducted experimental studies to evaluate how global change affects ecosystem and biogeochemical coupling and their relationships with ecosystem functioning. For this, we seek to collate existing biotic, abiotic and ecosystem function data from field experiments carried out across the globe. We anticipate that this new collaborative global synthesis will help us gain novel scientific insights that would be out of reach for individual research groups. It will also allow for the initiation of a meaningful dialogue between experimental ecologists and a wide range of stakeholders and end users aimed at preserving and enhancing ecosystem functioning through strengthening ecosystem and biogeochemical coupling.

Keywords
Collaboration

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DOI 10.25674/so92iss1pp8

Bernhard Seifert

Title: A taxonomic revision of the Palaearctic members of the subgenus Lasius s.str. (Hymenoptera, Formicidae)

Abstract
A revision of the Palaearctic members of the ant subgenus Lasius s.str. is presented the fundamentals of which are application of Numeric Morphology-Based Alpha-Taxonomy (NUMOBAT), investigation of type specimens of 58 taxa, critical evaluation of original descriptions of further 22 taxa, and decision-making based on the GAGE species concept. Excluding nomina nuda and unavailable names, 80 taxa are considered which divide into 56 recognized good species (with 16 of these described here as new), 12 junior synonyms, 11 incertae sedis, and one name representing a F1 hybrid. Eighteen phenotypic characters – seven shape, eight seta and two pubescence characters as well as absolute size – were recorded numerically in 4900 worker individuals originating from 1722 nest or spot samples. The subdivision of the subgenera Lasius s.str. Ruzsky 1913, Cautolasius Wilson 1955, Dendrolasius Ruzsky 1913, Chthonolasius Ruzsky 1913 and Austrolasius Faber 1967 is clearly confirmed by morphological data with each of the 99 recognized Palaearctic species being unambiguously assignable to either subgenus. A key to the 56 Palaearctic species of Lasius s.str., subdivided into five geographic regions, is presented. All species are depicted as z-stack photos in two standard positions. The new species Lasius precursor sp. nov. is proposed as a model for transition from a largely monogynousmonodomous social type (exemplified by the sister species Lasius turcicus Santschi 1921) to a supercolonial type (exemplified by the closely related species Lasius neglectus Van Loon et al. 1990).

Keywords
numeric morphology-based alpha-taxonomy, nest centroid clustering, cryptic species

PDF (4,21 MB)
PDF (high quality 40 MB)
+ The Supplementary Informations SI1 and SI2 are downloadable as digital material

DOI 10.25674/so92iss1pp15

Bernhard Seifert

Title: Corrigendum Seifert and Prosche (2017): Longterm development of ant assemblages of recultivated woodland and free-succession open-land habitats in a former strip mining area. Soil Organisms 89(3): 157-176.

Abstract
In an email to Soil Organisms from Feb., 27th 2020 Alexander Prosche retracted an article published with him as co-author. The first author Bernhard Seifert, therefore, herewith declares: The field work on study plot SP 238 was done by Alexander Prosche with only short-term participation and supervision by Bernhard Seifert. All data on this test plot and any conclusion drawn in this context in Seifert & Prosche (2017) are not credible and must be retracted.

Keywords
Corrigendum

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DOI 10.25674/so92iss1pp13