SOIL ORGANISMS

2021 Issues

Issue 93 (1) April

 

Content

 

AGENCY REPORT

Moritz Nabel, Christian Selig, Johanna Gundlach, Henrike von der Decken & Manfred Klein
Biodiversity in agricultural used soils: Threats and options for its conservation in Germany and Europe

Christin Hemmerling, Liliane Ruess & Michael Ackermann
The nematode fauna from the top soil to the vadose zone in a forested groundwater recharge area

Farid Faraji & Paul H. Hoekstra
Some new species records of the predatory mite family Phytoseiidae (Acari: Mesostigmata) from The Netherlands

Jörg Römbke, Stephan Jänsch, Rüdiger M. Schmelz
The abundance and diversity of Enchytraeidae and Naididae (Oligochaeta) in Amazonian forest ecosystems at different stages of human impact

CALL FOR COLLOBORATION

Ika Djukic, Sebastian Kepfer-Rojas, Inger Kappel Schmidt, Klaus Steenberg Larsen, Claus Beier, Björn Berg, Kris Verheyen, Stacey M. Trevathan-Tackett, Peter I. Macreadie, Michael Bierbaumer, Guillaume Patoine, Nico Eisenhauer, Carlos A. Guerra, Fernando T. Maestre, Frank Hagedorn, Alessandro Oggioni, Caterina Bergami, Barbara Magagna, TaeOh Kwon, Hideaki Shibata & TeaComposition initiative
The TeaComposition Initiative: Unleashing the power of international collaboration to understand litter decomposition

All articles

AGENCY REPORT
Biodiversity in agricultural used soils: Threats and options for ist conservation in Germany and Europe

Moritz Nabel, Christian Selig, Johanna Gundlach, Henrike von der Decken & Manfred Klein

 

Abstract

Agriculture and soil biodiversity are highly interdependent. Agriculture strongly depends on essential ecosystem services of an active and diverse soil life, leading to soil fertility. Fertile soil is the basis for the cultivation of vital, robust and productive crops. However, today’s intensive agriculture partly aims at replacing certain natural ecosystem services by intense agricultural practices and the use of agrochemicals. Even more, these intensive practices including intense mechanical soil tillage, pollution from contaminated fertilizers and pesticides pose direct threats to soil biodiversity. Although the biggest share of soil biodiversity has not yet been taxonomically recorded, there is evidence of a decline in soil biodiversity. There are many opportunities in agriculture to support an active and diverse soil life and profit from its related ecosystem services. Here we present a set of actions to promote soil biodiversity in agricultural used soils including measures from integrated pest and nutrient management, conservation soil cultivation and agricultural diversification. All these actions show synergies for a transition of agricultural productions systems to a more sustainable and climate change smart production. This transition process needs to be understood as a process relevant to society as a whole. Therefore, extra efforts cannot be borne by farmers alone, but adequate subsidies with a clear focus on soil biodiversity need to be implemented in agricultural policies on national and international level. At international level the 15th Conference of the Parties of the Convention on Biodiversity (CBD COP15) can set the frame for the future of soil biodiversity. On European and national level, the Common Agricultural Policy (CAP) and its implementation via the national strategic plans will be key for a transition to a soil biodiversity promoting agricultural production. Investments in research and development help to continuously develop measures and legal frameworks and to invest in effective soil protection in the long term.

Keywords Soil Biodiversity, Agriculture, Ecosystem Services, Threats, Conservation

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DOI 10.25674/so93iss1pp1

The nematode fauna from the top soil to the vadose zone in a forested groundwater recharge area

Christin Hemmerling, Liliane Ruess & Michael Ackermann

 

Abstract

Soil nematodes are major microfaunal grazers that drive the turnover of organic matter as they foster the activity of microorganisms. The latter are an essential component for water purification processes. The present study is the first study that investigates the nematode community along an entire depth transect from top soil to the vadose zone at a forested groundwater recharge area, the “Lange Erlen”, which provides drinking water to the city of Basel (Switzerland). Vertical core drills were performed from 0 – 450 cm depth at two locations in the study area. The vertical transect was divided into 30 cm thick soil sections. Nematodes were extracted, counted, identified and divided into five trophic groups (i.e. plant feeders, fungal feeders, bacterial feeders, omnivores, predators). Based on the classification of functional groups the Maturity Index (MI), Plant Parasitic Index (PPI), as well as the Shannon-Weaver Index (H’) were assessed. A total of 67 taxa were identified comprising 26 nematode families. The nematode population density was low with an average of 6.26 and 0.85 ind./10 g DW soil across depths at the sampling sites HST and VW, respectively. Density decreased strongly with depth, with on average 46% of the total nematode density located in the uppermost soil layer (0 – 30 cm). Although soil samples were taken down to a depth of 450 cm, no nematodes were found below 240 cm, except for Cephalobus persegnis Bastian, 1865, which was the only species present in the lower vadose zone (220 – 450 cm). Plant feeders were the dominant trophic group (65%) throughout the entire depth transect. Decomposition was mainly mediated by the bacterial carbon and energy channel as indicated by the low number of fungal feeders. The general low MI, PPI and H’ were neither depth nor site dependent, suggesting similar environmental conditions at the two investigated locations due to frequent flooding. SIMPER analysis revealed that the dissimilarity in nematode community patterns at HST and VW increased with depth. Plant feeders contributed to the community dissimilarity in the upper soil layers, while the impact of bacterial feeders increased with depth, indicating that the main resource changes along the depth profile.

Keywords
flooding, depth transect, soil microfauna, species composition, diversity, trophic structure

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DOI 10.25674/so93iss1pp13

Some new species records of the predatory mite family Phytoseiidae (Acari: Mesostigmata) from The Netherlands

Farid Faraji & Paul H. Hoekstra

 

Abstract

Thirteen species of phytoseiid mites collected from the Netherlands are re-described and illustrated. Among them 9 are new species records for the Dutch fauna and Metaseiulus (Metaseiulus) smithi (Schuster, 1957) is a new record for Europe. Metaseiulus (Metaseiulus) neosmithi nom. nov. Faraji is proposed as a replacement name for Metaseiulus (Metaseiulus) smithi Denmark & Evans, 2011. Also, Kampimodromus coryli Meshkov, 1999 is considered as a junior synonym of Kampimodromus langei (Wainstein & Arutunjan, 1973).

Keywords
Biodiversity, Biological control, Dutch fauna, Gamasida, Taxonomy

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DOI 10.25674/so93iss1pp35

The abundance and diversity of Enchytraeidae and Naididae (Oligochaeta) in Amazonian forest ecosystems at different stages of human impact

Jörg Römbke, Stephan Jänsch & Rüdiger M. Schmelz

 

Abstract

Enchytraeidae are known to be an important group of soil animals in temperate regions of the world but their diversity as well as their contribution to soil functions, esp. litter decomposition, in the humid tropics remain largely unexplored. Therefore, as part of the SHIFT (‘Studies of Human Impact on Floodplains and Forests in the Tropics’) project ENV 52, entitled ‘Soil Fauna and Litter Decomposition’, their species composition, abundance and biomass were determined in an experimental agroforestry area located about 20 km north of Manaus (Amazonia), Brazil, between 1997 and 2000, focusing on four plots with differing degree of human impact. In addition, individuals of the family Naididae were sampled at these plots as well. The aim of the project was to study the regeneration and anthropogenic usage of degraded forest areas, to mitigate the human impact on primary rain forests in Amazonia. Study sites were two polyculture tree plantations (POA, POC) and two plots of nearby secondary (growing since 1984, SEC) and undisturbed primary forest (FLO). Samples for both Enchytraeidae and Naididae were taken quarterly for two years and the worms were extracted by wet extraction (120 samples, each divided into litter and soil layer) per sampling date. The enchytraeids were identified in vivo, whereas naidids were initially only counted. Later on, and after fixation in EtOH, selected specimens were identified. Identification of the worms followed a site-specific key, based on information from the literature and own experience. The biomass of larger enchytraeids (i.e., the genus Guaranidrilus) was determined via weighing, while the biomass of smaller enchytraeids was estimated by using values previously determined for European species of similar size. In total, 18 enchytraeid and 14 naidid species were found. Most of the former belonged to the mainly neotropical genus Guaranidrilus (5) and to the cosmopolitan genus Hemienchytraeus (5). Species of genera typical for temperate regions, such as Achaeta spp. (4) and Enchytraeus spp. (2) were also found. The abundance of enchytraeids found in the primary forest (1,000–10,000 Ind/m²) was comparable to those found at other tropical rain forest sites. The abundance in all four plots was similar, whereas the biomass was lower in POA and POC than in FLO and SEC. However, variability between replicates was high. No annual phenology pattern was observed, but dry conditions in 1997 had a negative influence on enchytraeids. The four plots were similar concerning species number and composition, but dominance patterns differed: the dominant genus in FLO was Hemienchytraeus, but Guaranidrilus on all other plots. Naidids seem to regularly occur in terrestrial samples of tropical rain forests; their species number was high in relation to their abundance but most species were new to science. The micro-annelid community indicated a clear distinction between forest (FLO, SEC) and plantation (POA, POC) sites.

Keywords
Microdriles, Brazil, land use change, tropical forest soil, Clitellata, soil ecology

PDF (4,21 MB)

DOI 10.25674/so93iss1pp59

CALL FOR COLLABORATION
The TeaComposition Initiative: Unleashing the power of international collaboration to understand litter decomposition

Ika Djukic, Carlos A. Guerra, Fernando T. Maestre, Frank Hagedorn, Alessandro Oggioni, Caterina Bergami, Barbara Magagna, TaeOh Kwon, Hideaki Shibata, Nico Eisenhauer, Guillaume Patoine, Michael Bierbaumer, Sebastian Kepfer-Rojas, Inger Kappel Schmidt, Klaus Steenberg Larsen, Claus Beier, Björn Berg, Kris Verheyen, Stacey M. Trevathan-Tackett, Peter I. Macreadie & TeaComposition initiative

 

Abstract

Collected harmonized data on global litter decomposition are of great relevance for scientists, policymakers, and for education of the next generation of researchers and environmental managers. Here we describe the TeaComposition initiative, a global and open research collaborative network to study organic matter decomposition in a standardized way allowing comparison of decomposition rate and carbon turnover across global and regional gradients of ecosystems, climate, soils etc. The TeaComposition initiative today involves 570 terrestrial and 300 aquatic ecosystems from nine biomes worldwide. Further, we describe how to get involved in the TeaComposition initiative by (a) implementing the standard protocol within your study site, (b) joining task forces in data analyses, syntheses and modelling efforts, (c) using collected data and samples for further analyses through joint projects, (d) using collected data for graduate seminars, and (e) strengthening synergies between biogeochemical research and a wide range of stakeholders. These collaborative efforts within/emerging from the TeaComposition initiative, thereby, will leverage our understanding on litter decomposition at the global scale and strengthen global collaborations essential for addressing grand scientific challenges in a rapidly changing world.

Keywords
Litter Carbon Turnover, Tea bag, Essential variable, Networking the Networks, Standard Observations

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DOI 10.25674/so93iss1pp73