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Christer Erseus - One of the best experts on this subject based on the ideXlab platform.
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a new scandinavian chamaedrilus species clitellata Enchytraeidae with additional notes on others
Zootaxa, 2018Co-Authors: Svante Martinsson, Marten J Klinth, Christer ErseusAbstract:Chamaedrilus (earlier referred to as Cognettia ) is a well-known genus of terrestrial and limnic enchytraeids, currently with 19 known species in the world. Some of its species are morphologically cryptic and can only be identified using genetic (DNA) information. Many of them reproduce asexually, and the prevalence of sexual mature individuals is generally low in the populations. Chamaedrilus asloae sp. nov. (Clitellata: Enchytraeidae) is described based on material from two rivers in Norway, one in Sweden, and from a wet deciduous forest in Denmark. With the material at hand, no morphological characters completely separate C. asloae from C. chalupskyi ; none of the available specimens of the new species are sexually mature. However, four molecular markers (two mitochondrial, two nuclear) support that C. asloae is a distinct, separately evolved lineage, which is sister to a clade consisting of C. glandulosus and C. varisetosus . In this study, too, the fully developed sexual organs of C. chalupskyi and C. varisetosus are described and illustrated.
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global checklist of species of grania clitellata Enchytraeidae with remarks on their geographic distribution
European journal of taxonomy, 2017Co-Authors: Alessandro Livio Prantoni, Paulo Da Cunha Lana, Christer ErseusAbstract:A checklist of all currently accepted species of Grania Southern, 1913 (Annelida, Clitellata, Enchytraeidae) is presented. The genus is widespread over the world and comprises 81 species described to date. Remarks on their geographical distribution, habitat, synonymies and museum catalogue numbers are provided.
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taxonomy of north european lumbricillus clitellata Enchytraeidae
ZooKeys, 2017Co-Authors: Marten J Klinth, Emilia Rota, Christer ErseusAbstract:: Lumbricillus is a genus of clitellate worms with about 80 described species that inhabit marine and limnic habitats. This study follows a recent analysis of the phylogeny of the genus based on 24 species of Lumbricillus collected mainly in Norway and Sweden. We provide the illustrated taxonomic descriptions of all these species and describe two of them as new; Lumbricillus latithecatussp. n. and L. scandicussp. n. Using the recent phylogeny, we informally divide Lumbricillus into five distinct morphological groups, into which we also tentatively place the Lumbricillus species not included in this study. Furthermore, we establish Claparedrilusgen. n., with the type species C. semifuscoidessp. n., and transfer Pachydrilus semifuscus Claparede, 1861 (previously referred to Lumbricillus) into said genus.
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placing the forgotten on the positions of euenchytraeus and chamaedrilus in an updated enchytraeid phylogeny clitellata Enchytraeidae
Invertebrate Systematics, 2017Co-Authors: Svante Martinsson, Emilia Rota, Klara Dozsafarkas, Christer ErseusAbstract:The phylogeny of Enchytraeidae was re-estimated to establish the relationships of the now resurrected Chamaedrilus and Euenchytraeus and to confirm their status as separate taxa. The former Cognettia (Enchytraeidae) was recently revised and split into its two senior synonyms, Chamaedrilus and Euenchytraeus, with the majority of the species transferred to Chamaedrilus. Euenchytraeus was re-established for three species sharing a unique anatomical trait, but has never before been represented in any phylogenetic study. We included representatives from 21 (of 33) valid enchytraeid genera and used three mitochondrial and four nuclear genes. The dataset (4164 base pairs) was analysed using multi-species coalescent (MSC) and maximum likelihood (ML) methods. Chamaedrilus (represented by eight species) and Euenchytraeus (represented by Eu. clarae) were found in a clade together with the monotypic Stercutus. Chamaedrilus was found to be monophyletic with maximum support in both analyses. The ML tree supported Euenchytraeus and Chamaedrilus as sister groups, whereas the MSC tree placed Euenchytraeus together with Stercutus, both with low support. A Bayes factor test weakly supported Euenchytraeus and Chamaedrilus as sister groups over Euenchytraeus Stercutus. Possible morphological synapomorphies for these genera are discussed, and we conclude that Chamaedrilus and Euenchytraeus are closely related, but their status as separate genera is justified.
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phylogeny and species delimitation of north european lumbricillus clitellata Enchytraeidae
Zoologica Scripta, 2017Co-Authors: Marten J Klinth, Svante Martinsson, Christer ErseusAbstract:The enchytraeid genus Lumbricillus comprises about 80 described species of clitellate worms, which are up to a few centimetres long, and they mostly inhabit the littoral zone of non-tropical marine and brackish waters world-wide. The phylogeny of this genus is poorly studied, but previous work has suggested that Lumbricillus is a non-monophyletic group. In this study, species boundaries and the phylogeny of this genus is re-assessed using more than 300 DNA-barcoded specimens (using COI mtDNA), part of which was also sequenced for two additional mitochondrial and four nuclear molecular markers. Statistical and coalescent based applications were used for the delimitation of a total of 24 species, of which 20 were identified as belonging to 17 described morphospecies; one morphospecies was found to be a complex of four delimited species, and another four delimited species could not be matched with any described species. Furthermore, gene trees, concatenation and multispecies coalescent based species trees were estimated using Bayesian inference. The estimated phylogenies confirm a non-monophyletic Lumbricillus as L. semifuscus is clearly excluded from the genus. Furthermore, the placement of a monophyletic clade consisting of L. arenarius, L. dubius, and an unidentified species varies between analyses; they are either found as the sister-group to the genus Grania or as sister-group to the remaining Lumbricillus, where the latter relationship is supported by the multispecies coalescent, which we consider as the most reliable method.
Emilia Rota - One of the best experts on this subject based on the ideXlab platform.
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Taxonomy and Ecology of Sponge-Associate Marionina spp. (Clitellata: Enchytraeidae) from the Horomatangi Geothermal System of Lake Taupo, New Zealand
International Review of Hydrobiology, 2020Co-Authors: Emilia Rota, Renata ManconiAbstract:The dissection of Heterorotula sponges collected in an area of geothermal activity at 126–145 m depth on the floor of Lake Taupo (de Rondeet al., 2002) revealed a dense population of associated Enchytraeidae. They represent three species of Marionina, two of which known but exotic (the Palaearctic M. ripariaBretscher, 1899 and the Chinese M. seminudaXie and Rota, 2001), and one new to science, M. spongicola sp. n. This is the first report of an ecological association between enchytraeids and poriferans in the lake profundal zone. The possible nature of such relationship (casual contact for feeding or dwelling for food and shelter) is discussed. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
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taxonomy of north european lumbricillus clitellata Enchytraeidae
ZooKeys, 2017Co-Authors: Marten J Klinth, Emilia Rota, Christer ErseusAbstract:: Lumbricillus is a genus of clitellate worms with about 80 described species that inhabit marine and limnic habitats. This study follows a recent analysis of the phylogeny of the genus based on 24 species of Lumbricillus collected mainly in Norway and Sweden. We provide the illustrated taxonomic descriptions of all these species and describe two of them as new; Lumbricillus latithecatussp. n. and L. scandicussp. n. Using the recent phylogeny, we informally divide Lumbricillus into five distinct morphological groups, into which we also tentatively place the Lumbricillus species not included in this study. Furthermore, we establish Claparedrilusgen. n., with the type species C. semifuscoidessp. n., and transfer Pachydrilus semifuscus Claparede, 1861 (previously referred to Lumbricillus) into said genus.
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placing the forgotten on the positions of euenchytraeus and chamaedrilus in an updated enchytraeid phylogeny clitellata Enchytraeidae
Invertebrate Systematics, 2017Co-Authors: Svante Martinsson, Emilia Rota, Klara Dozsafarkas, Christer ErseusAbstract:The phylogeny of Enchytraeidae was re-estimated to establish the relationships of the now resurrected Chamaedrilus and Euenchytraeus and to confirm their status as separate taxa. The former Cognettia (Enchytraeidae) was recently revised and split into its two senior synonyms, Chamaedrilus and Euenchytraeus, with the majority of the species transferred to Chamaedrilus. Euenchytraeus was re-established for three species sharing a unique anatomical trait, but has never before been represented in any phylogenetic study. We included representatives from 21 (of 33) valid enchytraeid genera and used three mitochondrial and four nuclear genes. The dataset (4164 base pairs) was analysed using multi-species coalescent (MSC) and maximum likelihood (ML) methods. Chamaedrilus (represented by eight species) and Euenchytraeus (represented by Eu. clarae) were found in a clade together with the monotypic Stercutus. Chamaedrilus was found to be monophyletic with maximum support in both analyses. The ML tree supported Euenchytraeus and Chamaedrilus as sister groups, whereas the MSC tree placed Euenchytraeus together with Stercutus, both with low support. A Bayes factor test weakly supported Euenchytraeus and Chamaedrilus as sister groups over Euenchytraeus Stercutus. Possible morphological synapomorphies for these genera are discussed, and we conclude that Chamaedrilus and Euenchytraeus are closely related, but their status as separate genera is justified.
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cryptic diversity among the achaetous marionina annelida clitellata Enchytraeidae
Systematics and Biodiversity, 2012Co-Authors: Lisa Matamoros, Emilia Rota, Christer ErseusAbstract:This study investigates the diversity and taxonomy of a mainly marine group of species lacking chaetae currently assigned to the genus Marionina. This achaetous group includes four nominal species: M. achaeta (Hagen, 1954), M. achaeta sensu Lasserre, 1964, M. nevisensis Righi & Kanner, 1979 and M. arenaria Healy, 1979. As Lasserre's (1964) M. achaeta appears to be morphologically different from its (then) senior homonym M. achaeta (Hagen, 1954), the replacement name M. nothachaeta nom. nov. is proposed for it. We studied the genetic and morphological diversity of achaetous specimens of Marionina collected in Florida, the Great Barrier Reef, New Caledonia, Sweden, England and the Bahamas. The collection localities are almost all supralittoral and often brackish-water habitats. Parts of the mitochondrial genes 12S, 16S, COI and the nuclear genes 18S, 28S and ITS were analysed to assess the genetic variation and phylogeny of the achaetous Marionina species. The molecular data reveal one monophyletic group of...
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molecular phylogeny of Enchytraeidae annelida clitellata
Molecular Phylogenetics and Evolution, 2010Co-Authors: Christer Erseus, Emilia Rota, Lisa MatamorosAbstract:A multigene data set (12S, 16S, and COI mitochondrial DNA; 18S and 28S nuclear DNA) was analyzed by Bayesian inference to estimate the phylogeny of a sample of the clitellate family Enchytraeidae (86 species representing 14 nominal genera). Monophyly, as well as a basal dichotomy, of the family Enchytraeidae obtained maximum support, with one clade containing Hemienchytraeus and Achaeta, the other the remaining 12 genera analysed. The latter group is basally resolved in several well-supported clades. Lumbricillus and Grania are closely related. Bryodrilus, Oconnorella, Henlea and two species of Marionina (M. cf. riparia, and M. communis) form a well-supported clade. Cognettia is sister to Stercutus, and Cernosvitoviella sister to Mesenchytraeus, and the four together appear to be a monophyletic group. A large part of the taxonomically problematic Marionina appears to be a group not closely related to the type species (M. georgiana), and this group also includes Enchytronia. Further, this Marionina/Enchytronia group appears to be sister to a clade comprising the more or less littoral marine genera Stephensoniella and Enchytraeus. Hemifridericia, Buchholzia and Fridericia, the three genera characterized by two types of coelomocytes, also form a well-supported clade. The study corroborates most of the multi-species genera analysed (Cognettia, Cernosvitoviella, Mesenchytraeus, Oconnorella, Henlea, Enchytraeus, Grania, Buchholzia and Fridericia); only Lumbricillus and Marionina are non-monophyletic as currently defined.
Rudiger M Schmelz - One of the best experts on this subject based on the ideXlab platform.
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On a collection of Enchytraeidae and Naididae (Oligochaeta) from the Tristan da Cunha Islands, South Atlantic Ocean
2020Co-Authors: Rudiger M Schmelz, Christine HanelAbstract:A small collection of enchytraeids and naidids comprises part of the "Empowering the People of Tristan da Cunha to Implement the Convention on Biodiversity" Project. Six taxa of Enchytraeidae were recognized: Cognettia sphagnetorum, Guaranidrilus sp., Lumbricillus sp., Achaeta sp., and Fridericia spp., the latter comprising at least two different species. Two species of naidids were identified, Nais variabilis and Pristina jenkinae. The bulk of specimens belongs to northern palaearctic C. sphagnetorum and to the mainly South American genus Guaranidrilus. The co-occurrence of these taxa suggests that the microdrile oligochaete fauna of the Tristan archipelago is a mix of immigrants from various parts of the world.
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case 3689 cognettia nielsen christensen 1959 annelida oligochaeta Enchytraeidae proposed precedence over euenchytraeus bretscher 1906 and chamaedrilus friend 1913
The Bulletin of zoological nomenclature, 2015Co-Authors: Rudiger M Schmelz, Rut Collado, Jörg RömbkeAbstract:Abstract. The purpose of this application, under Articles 23.2 and 23.9.3 of the Code, is to conserve the usage of the genus-group name Cognettia Nielsen & Christensen, 1959 (Enchytraeidae, Oligochaeta, Annelida) for a genus of annelid worms (type species Pachydrilus sphagnetorum Vejdovský, 1878 (‘1877’)). Cognettia, a name for a Holarctic genus of terrestrial and semi-aquatic annelid worms, is threatened by two subjective senior synonyms, Euenchytraeus Bretscher, 1906 and Chamaedrilus Friend, 1913. If these two names are considered synonyms, Euenchytraeus will replace Cognettia; if they are considered to represent two different genera, Chamaedrilus will replace Cognettia. In 2015 Martinsson et al. adopted the latter course, replacing Cognettia by Chamaedrilus, and allocated its species between both Euenchytraeus and Chamaedrilus. Cognettia is a widely used name and is well-known in the fields of soil biology, ecology, and ecotoxicology, and we propose it be given precedence over Chamaedrilus and Euenchyt...
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Case 3689 Cognettia Nielsen & Christensen, 1959 (Annelida, Oligochaeta, Enchytraeidae ): proposed precedence over Euenchytraeus Bretscher, 1906 and Chamaedrilus Friend, 1913
The Bulletin of zoological nomenclature, 2015Co-Authors: Rudiger M Schmelz, Rut Collado, Jörg RömbkeAbstract:Abstract. The purpose of this application, under Articles 23.2 and 23.9.3 of the Code, is to conserve the usage of the genus-group name Cognettia Nielsen & Christensen, 1959 (Enchytraeidae, Oligochaeta, Annelida) for a genus of annelid worms (type species Pachydrilus sphagnetorum Vejdovský, 1878 (‘1877’)). Cognettia, a name for a Holarctic genus of terrestrial and semi-aquatic annelid worms, is threatened by two subjective senior synonyms, Euenchytraeus Bretscher, 1906 and Chamaedrilus Friend, 1913. If these two names are considered synonyms, Euenchytraeus will replace Cognettia; if they are considered to represent two different genera, Chamaedrilus will replace Cognettia. In 2015 Martinsson et al. adopted the latter course, replacing Cognettia by Chamaedrilus, and allocated its species between both Euenchytraeus and Chamaedrilus. Cognettia is a widely used name and is well-known in the fields of soil biology, ecology, and ecotoxicology, and we propose it be given precedence over Chamaedrilus and Euenchyt...
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Enchytraeidae (Oligochaeta, Annelida) from a field site in Portugal, with the description of five new species and a redescription of Enchylea heteroducta Nielsen & Christensen, 1963
Zootaxa, 2013Co-Authors: Rudiger M Schmelz, Rut ColladoAbstract:Five new species of terrestrial Enchytraeidae (Oligochaeta, Clitellata) are described from an experimental field area in Portugal. Achaeta coimbrensis sp. nov. belongs to a group of species without pyriform glands and with lateral spermathecal ectal pores. Fridericia sousai sp. nov., F. roembkei sp. nov., F. marginata sp. nov., and F. ciliotheca sp. nov. have a maximum of four chaetae per bundle and two spermathecal diverticula, a character combination shared by c. 30 other species of this genus. The new Fridericia species are distinguished from these congeners by combinations of characters, but the ventral pattern of the clitellum alone is sufficient to separate the new species from each other. Enchylea heteroducta Nielsen & Christensen, 1963 is redescribed, this being the first record after the original description and the first record from a natural habitat. Further 16 species of enchytraeids are recorded, and there are now 32 species of enchytraeids known from Portugal.
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an updated checklist of currently accepted species of Enchytraeidae oligochaeta annelida
2012Co-Authors: Rudiger M Schmelz, Rut ColladoAbstract:An updated checklist of all currently accepted species of Enchytraeidae (Oligochaeta, Clitellata, Annelida) is presented. The list comprises 676 species, which add up to 715 species-group taxa when subspecies and controversial species are included. Species-richest genera are Fridericia (99 species) and Marionina (96 species), followed by Lumbricillus (80 species), Mesenchytraeus (76 species), and Grania (71 species). Six genera are monospecific. Given the generally poor knowledge of Enchytraeidae in most regions on earth, these numbers most probably represent only a minute fraction of the actual diversity, but reasonable estimates as to the actual number of enchytraeid species are not possible at present. For reasons of homonymy, Henlea dicksoni (Nurminen, 1980) and Henlea irkutensis (Nurminen, 1980) are renamed into Henlea dicksoniana and Henlea irkutiana, respectively.
Stefan Schrader - One of the best experts on this subject based on the ideXlab platform.
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Interrelation between soil physical properties and Enchytraeidae abundances following a single soil compaction in arable land
Journal of Plant Nutrition and Soil Science, 1999Co-Authors: Marcus Langmaack, C. Wiermann, Stefan SchraderAbstract:In spring 1995 a silty clay soil was compacted dynamically by wheeling with graded wheel loads up to 6 times. The reaction towards wheeling was recorded immediately. In the following 3 years some soil physical parameters as well as the Enchytraeidae abundances were recorded regularly. To the first wheeling, the soil reacted plastically in vertical direction. The reaction became elastically after the 4th wheeling. After the 6th passage with a 5‒tonnes wheel load soil structure collapsed totally, which can be concluded from the stress ratios. After the wheeling event, abundances of Enchytraeidae decreased obviously compared to uncompacted plots. The increase in air permeability, air capacity, and the decrease of soil bulk density depend on primary tillage events. The recovery of Enchytraeidae abundances developed in parallel. Abundances seem to be regenerated in the 3rd year after the wheeling event. Primary tillage can help to induce biological and macroscopic structural regeneration of the top soil after a compaction event. Zusammenhang zwischen bodenphysikalischen Eigenschaften und Enchytraeiden‒Abundanzen nach einmaliger Bodenverdichtung von Ackerflachen Nach einer dynamischen 6fachen Verdichtung eines schluffigen Tonbodens durch Uberrollung mit abgestuften Radlasten im Fruhjahr 1995, wurden uber 3 Jahre regelmasig verschiedene bodenphysikalische Parameter sowie die Enchytraeidae‒Abundanzen gemessen. Die Reaktion des Bodens auf die Uberrollung wurde unmittelbar aufgenommen. Der Boden reagierte zunachst in vertikaler Richtung plastisch, zeigte aber nach der 4. Uberrollung deutlich elastisches Verhalten. Die Spannungsrelationen zueinander lassen den Schlus zu, das es nach 6maliger Uberrollung mit 5 t Radlast zu einer totalen Homogenisierung des Bodens kommt. Nach der Uberrollung waren die Enchytraeidae‒Abundanzen gegenuber unbelasteten Parzellen deutlich erniedrigt. Die Zunahme der Luftkapazitat und ‒permeabilitat und die Abnahme der Lagerungsdichten sind von der Grundbodenbearbeitung abhangig. Parallel dazu erholten sich die Enchytraeidae‒Abundanzen, wenn auch erst deutlich im 3. Jahr. Durch die Grundbodenbearbeitung wird die biologische und makroskopische strukturelle Regeneration von verdichtetem Oberboden miteingeleitet.
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tillage systems and soil compaction their impact on abundance and vertical distribution of Enchytraeidae
Soil & Tillage Research, 1998Co-Authors: Rudiger Rohrig, Marcus Langmaack, Stefan Schrader, Otto LarinkAbstract:Abstract We quantified the development of Enchytraeidae (potworms) abundances and vertical distribution in mechanically stressed soils for 1 year. To assess the effects of soil compaction due to cultivation practice on arable land, two agricultural locations were chosen, differing in soil type, annual rainfall, and soil tillage: (1) conservation tillage (CS) with rotary harrow and conventional tillage (CT) with plough, (2) conventional tillage with spading machine in two depths (CT (shallow) and CT (deep)). Three plots of each tillage system were mechanically compacted by wheeling with graded loads: 0 t, 2 × 2.5 t, 6 × 5 t (wheeling frequency X wheel load) in early spring 1995. CS had a positive effect on the abundances. The different tillage depth of the systems used influenced the vertical distribution. Soil compaction resulted in significantly lower individual numbers and a disturbed vertical distribution. The abundances did not regenerate in one annual cycle on the mechanically compacted plots but vertical distribution did. Because of the low abundances, the Enchytraeidae on the compacted plots cannot fulfil their important function in microstructure development and their effects on soil properties. Furthermore, there are hints towards an increased sensitivity to soil frost events in compacted CT plots.
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impact of collembola and Enchytraeidae on soil surface roughness and properties
Biology and Fertility of Soils, 1997Co-Authors: Stefan Schrader, Marcus Langmaack, K HelmingAbstract:The aim of the study was to quantify the alteration of soil surface roughness caused by the casting activity of mesofauna. Undisturbed soil monoliths with a surface area of 5000mm2 were taken from the upper 4cm of the Ap-horizon in agricultural land. Two tillage systems were studied: conventional tillage (CT) and conservation tillage (CS). The sampling plots were mechanically compacted by wheeling with graded loads. Sampling occurred in spring after compaction and before seeding. The soil monoliths were defaunated before inoculating one half of the monoliths with 150 individuals of Collembola (Folsomia candida) and the other half with 100 individuals of Enchytraeidae (90% Enchytraeus minutus and 10% E. lacteus). Soil surface roughness was measured using a noncontact laser scanner: before inoculation and 6 months later. Photographs show the soil surface covered with casts. Results from laser scanning show that in most cases the surface roughness increased due to mesofaunal activity. However, roughness decreased when cracks were filled with casts. The casting activity and surface roughness changes are highest in uncompacted soil. A high degree of soil compaction significantly reduced the activity at the surface. In most cases the soil surface is more altered in CT than in CS. When the content of carbon and nitrogen were determined, both elements were accumulated in the casts but more by Collembola than Enchytraeidae. The results are discussed in the context of the hemiedaphic (F. candida) and the euedaphic (Enchytraeus spp.) mode of living.
Marcus Langmaack - One of the best experts on this subject based on the ideXlab platform.
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Interrelation between soil physical properties and Enchytraeidae abundances following a single soil compaction in arable land
Journal of Plant Nutrition and Soil Science, 1999Co-Authors: Marcus Langmaack, C. Wiermann, Stefan SchraderAbstract:In spring 1995 a silty clay soil was compacted dynamically by wheeling with graded wheel loads up to 6 times. The reaction towards wheeling was recorded immediately. In the following 3 years some soil physical parameters as well as the Enchytraeidae abundances were recorded regularly. To the first wheeling, the soil reacted plastically in vertical direction. The reaction became elastically after the 4th wheeling. After the 6th passage with a 5‒tonnes wheel load soil structure collapsed totally, which can be concluded from the stress ratios. After the wheeling event, abundances of Enchytraeidae decreased obviously compared to uncompacted plots. The increase in air permeability, air capacity, and the decrease of soil bulk density depend on primary tillage events. The recovery of Enchytraeidae abundances developed in parallel. Abundances seem to be regenerated in the 3rd year after the wheeling event. Primary tillage can help to induce biological and macroscopic structural regeneration of the top soil after a compaction event. Zusammenhang zwischen bodenphysikalischen Eigenschaften und Enchytraeiden‒Abundanzen nach einmaliger Bodenverdichtung von Ackerflachen Nach einer dynamischen 6fachen Verdichtung eines schluffigen Tonbodens durch Uberrollung mit abgestuften Radlasten im Fruhjahr 1995, wurden uber 3 Jahre regelmasig verschiedene bodenphysikalische Parameter sowie die Enchytraeidae‒Abundanzen gemessen. Die Reaktion des Bodens auf die Uberrollung wurde unmittelbar aufgenommen. Der Boden reagierte zunachst in vertikaler Richtung plastisch, zeigte aber nach der 4. Uberrollung deutlich elastisches Verhalten. Die Spannungsrelationen zueinander lassen den Schlus zu, das es nach 6maliger Uberrollung mit 5 t Radlast zu einer totalen Homogenisierung des Bodens kommt. Nach der Uberrollung waren die Enchytraeidae‒Abundanzen gegenuber unbelasteten Parzellen deutlich erniedrigt. Die Zunahme der Luftkapazitat und ‒permeabilitat und die Abnahme der Lagerungsdichten sind von der Grundbodenbearbeitung abhangig. Parallel dazu erholten sich die Enchytraeidae‒Abundanzen, wenn auch erst deutlich im 3. Jahr. Durch die Grundbodenbearbeitung wird die biologische und makroskopische strukturelle Regeneration von verdichtetem Oberboden miteingeleitet.
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tillage systems and soil compaction their impact on abundance and vertical distribution of Enchytraeidae
Soil & Tillage Research, 1998Co-Authors: Rudiger Rohrig, Marcus Langmaack, Stefan Schrader, Otto LarinkAbstract:Abstract We quantified the development of Enchytraeidae (potworms) abundances and vertical distribution in mechanically stressed soils for 1 year. To assess the effects of soil compaction due to cultivation practice on arable land, two agricultural locations were chosen, differing in soil type, annual rainfall, and soil tillage: (1) conservation tillage (CS) with rotary harrow and conventional tillage (CT) with plough, (2) conventional tillage with spading machine in two depths (CT (shallow) and CT (deep)). Three plots of each tillage system were mechanically compacted by wheeling with graded loads: 0 t, 2 × 2.5 t, 6 × 5 t (wheeling frequency X wheel load) in early spring 1995. CS had a positive effect on the abundances. The different tillage depth of the systems used influenced the vertical distribution. Soil compaction resulted in significantly lower individual numbers and a disturbed vertical distribution. The abundances did not regenerate in one annual cycle on the mechanically compacted plots but vertical distribution did. Because of the low abundances, the Enchytraeidae on the compacted plots cannot fulfil their important function in microstructure development and their effects on soil properties. Furthermore, there are hints towards an increased sensitivity to soil frost events in compacted CT plots.
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impact of collembola and Enchytraeidae on soil surface roughness and properties
Biology and Fertility of Soils, 1997Co-Authors: Stefan Schrader, Marcus Langmaack, K HelmingAbstract:The aim of the study was to quantify the alteration of soil surface roughness caused by the casting activity of mesofauna. Undisturbed soil monoliths with a surface area of 5000mm2 were taken from the upper 4cm of the Ap-horizon in agricultural land. Two tillage systems were studied: conventional tillage (CT) and conservation tillage (CS). The sampling plots were mechanically compacted by wheeling with graded loads. Sampling occurred in spring after compaction and before seeding. The soil monoliths were defaunated before inoculating one half of the monoliths with 150 individuals of Collembola (Folsomia candida) and the other half with 100 individuals of Enchytraeidae (90% Enchytraeus minutus and 10% E. lacteus). Soil surface roughness was measured using a noncontact laser scanner: before inoculation and 6 months later. Photographs show the soil surface covered with casts. Results from laser scanning show that in most cases the surface roughness increased due to mesofaunal activity. However, roughness decreased when cracks were filled with casts. The casting activity and surface roughness changes are highest in uncompacted soil. A high degree of soil compaction significantly reduced the activity at the surface. In most cases the soil surface is more altered in CT than in CS. When the content of carbon and nitrogen were determined, both elements were accumulated in the casts but more by Collembola than Enchytraeidae. The results are discussed in the context of the hemiedaphic (F. candida) and the euedaphic (Enchytraeus spp.) mode of living.