Oligochaete distribution patterns in two German hardwater lakes of different trophic state

AbstractWe investigated the effect of contrasting trophic conditions on the distribution and dominance patterns of Oligochaeta species assemblages in lake sediments and their relation to the environmental variables depth, season, and substrate. The study was performed on the highly eutrophic Lake Haussee and the oligotrophic Lake Stechlin, both hardwater lakes in the Baltic Lake District of Northern Germany. Quantitative monthly and seasonal sampling took place over one year at 14 representative sites, covering littoral and profundal sediments of both lakes. Between-lake differences in the profundal were clearcut with an absence of any zoobenthos in Lake Haussee and a peculiar meiobenthic species assemblage in Lake Stechlin (Collado et al. 1999). Between-lake differences in the littoral, however, were small and mainly attributable to a small number of species exclusive to Lake Stechlin and an overall higher abundance of oligochaetes, especially naidids, in Lake Haussee. Species-richest family in both lakes were Naididae; Tubificidae were dominant in Lake Stechlin; in Lake Haussee Tubificidae and Naididae were equally abundant. Most striking were diversity of habitat types and species distribution patterns in the littoral. Multivariate analysis (CA, CCA) showed that the distribution patterns of oligochaete species assemblages are significantly correlated with depth, season and substrate. Depth is the major factor when the whole water body is considered. When confining to the littoral, species abundance and distribution are strongly related to seasonality and substrate type. Naididae show, in general, maximal abundances in autumn and summer and a preference for plants, plant debris and soft sediments; Tubificidae are more abundant in spring and prefer mineral substrate. The relation between seasonality, substrate and food availability is discussed

Description of Enchytronia pygmaea sp. n. (Enchytraeidae, Clitellata), a very small enchytraeid in European soils

A new and very small European species of terrestrial enchytraeids is described, Enchytronia pygmaea sp. nov. (Enchytraeidae, Oligochaeta). It differs from all enchytraeids known so far in the chaetal pattern: lateral bundles have 2 chaetae from segment II to V, 0 from segment VI to XII–XV, and only 1 chaeta in lateral postclitellar bundles; ventral bundles have 2 chaetae. A further peculiarity is the presence of only 1 pair of preclitellar nephridia. The species must be considered as widespread as it is recorded here from 17 different localities distributed over seven European countries ranging from the Atlantic to the Mediterranean zone

On a collection of enchytraeids (Oligochaeta) from first order streams in São Paulo State, Brazil

A collection of 21 ethanol-preserved specimens of enchytraeids collected in first order streams in São Paulo State, Brazil, was whole-mounted on slides and investigated under light microscope. Eight species taxa were distinguished, belonging to Achaeta, Guaranidrilus, and Marionina. Five species could be named, one of them tentatively: Achaeta neotropica Černosvitov, 1937, Achaeta singularis Schmelz, 2008, Guaranidrilus oiepe Righi, 1974, Marionina argentea (Michaelsen, 1889) s.l., Marionina cf. seminuda Xie & Rota, 2001. Three further unnamed species taxa of Guaranidrilus were distinguished; two of them may be new species. The presence of sexually mature specimens of A. singularis allowed an emendation of the original description which was based on juvenile specimens. The rod-shaped crystals in the coelom of A. singularis are similar to raphides in plants and sponges, an

Effects of organic pesticides on enchytraeids (Oligochaeta) in agroecosystems: laboratory and higher-tier tests

Enchytraeidae (Oligochaeta, Annelida) are often considered to be typical forestliving organisms, but they are regularly found in agroecosystems of the temperate regions of the world. Although less known than their larger relatives, the earthworms, these saprophagous organisms play similar roles in agricultural soils (but at a smaller scale), e.g., influencing soil structure and organic matter dynamics via microbial communities, and having a central place in soil food webs. Their diversity is rarely studied or often underestimated due to difficulties in distinguishing the species. New genetic techniques reveal that even in anthropogenically highly influenced soils, more than 10 species per site can be found. Because of their close contact with the soil pore water, a high ingestion rate and a thin cuticle, they often react very sensitively to a broad range of pesticides. Firstly we provide a short overview of the diversity and abundance of enchytraeid communities in agroecosystems. Afterwards, we explore the available data on enchytraeid sensitivity toward pesticides at different levels of biological organization, focusing on pesticides used in (mainly) European agroecosystems. Starting with non-standardized studies on the effects of pesticides on the sub-individual level, we compile the results of standard laboratory tests performed following OECD and ISO guidelines as well as those of higher-tier studies (i.e., semi-field and field tests). The number of comparable test data is still limited, because tests with enchytraeids are not a regulatory requirement in the European Union. While focusing on the effects of pesticides, attention is also given to their interactions with environmental stressors (e.g., climate change). In conclusion, we recommend to increase the use of enchytraeids in pesticide risk assessment because of their diversity and functional importance as well as their increasingly simplified use in (mostly standardized) tests at all levels of biological organization

A proposed order-level classification in Oligochaeta (Annelida, Clitellata)

The purpose of our contribution is to propose a robust and practical order-level classification of the families of Oligochaeta, that is, non-leech Clitellata. The order level is mandatory in Linnaean rank-based classification and is also required in many internet-based biodiversity databases. However, it has received little attention in oligochaete systematics, and the few available order-level classifications of Oligochaeta no longer represent phylogenetic relationships adequately. Our proposal is based on corroborated molecular phylogenetic evidence and takes as benchmarks class level for Clitellata, subclass level for Oligochaeta and Hirudinea, and order level for Crassiclitellata, the monophylum that includes most of the earthworm taxa. As a result, eleven orders are proposed: A lluroididA Timm & Martin, 2015; CApilloventridA Timm, n. ordo; CrAssiClitellAtA Jamieson, 1988; enChytrAeidA Kasprzak, 1984; hAplotAxidA Brinkhurst & Jamieson, 1971; lumbriCulidA Brinkhurst & Jamieson, 1971; moniligAstridA Brinkhurst & Jamieson, 1971; nArApidA Timm, n. ordo; pArvidrilidA Timm, n. ordo; rAndiellidA Jamieson, 1988; tubifiCidA Jamieson, 1978. This order-level classification is robust and easily adaptable to future insights into phylogenetic relationships

Polychaetes and oligochaetes associated with intertidal rocky shores in a semi-enclosed industrial and urban embayment, with the description of two new species

The species composition and relative abundance of the annelid benthic macrofauna (Polychaeta and Oligochaeta) inhabiting the rocky intertidal zone of the ria of Ferrol (Galicia, NW Spain) were studied during field collections, from 2000 to 2002. A total of 14,619 specimens (11,585 polychaetes belonging to 76 species and 24 families and 3,034 oligochaetes belonging to 18 species and two families) were collected from 98 quantitative samples taken from 13 sampling sites. The general spatial distribution of the annelid fauna reflects an increase of the diversity from the inner to the outer part of the ria. The general patterns found in the annelid composition suggest that the assemblages were dominated by oligochaetes in the inner sheltered sampling sites and polychaetes in the outer more exposed sites. Several faunistical and taxonomical remarks on selected species are presented. Two new species of oligochaetes are described: Coralliodrilus artabrensis sp. n. and Pirodrilus fungithecatus sp. n. (Naididae, Phallodrilinae). A new biological index, based on the oligochaete/polychaete ratio (O/P), is proposed as tool to evaluate environmental quality and to monitor future changes in the environment.Xunta de Galicia. CGL2004-04680-C10-02Ministerio de Educación y Ciencia. CGL.2006-1341

Earthworm functioning in soil ecosystem services in relation to land use intensity

The FP7 EcoFINDERS project aimed to assess the relationship between soil biodiversity and ecosystem service provision. We studied functional responses for earthworms and fungi on soil formation and water regulation under different agricultural land uses representing a range in land use intensity. The aim was to establish and quantify these functional relationships by literature and field studies

Effects of Organic Pesticides on Enchytraeids (Oligochaeta) in Agroecosystems: Laboratory and Higher-Tier Tests

Enchytraeidae (Oligochaeta, Annelida) are often considered to be typical forestliving organisms, but they are regularly found in agroecosystems of the temperate regions of the world. Although less known than their larger relatives, the earthworms, these saprophagous organisms play similar roles in agricultural soils (but at a smaller scale), e.g., influencing soil structure and organic matter dynamics via microbial communities, and having a central place in soil food webs. Their diversity is rarely studied or often underestimated due to difficulties in distinguishing the species. New genetic techniques reveal that even in anthropogenically highly influenced soils, more than 10 species per site can be found. Because of their close contact with the soil pore water, a high ingestion rate and a thin cuticle, they often react very sensitively to a broad range of pesticides. Firstly we provide a short overview of the diversity and abundance of enchytraeid communities in agroecosystems. Afterwards, we explore the available data on enchytraeid sensitivity toward pesticides at different levels of biological organization, focusing on pesticides used in (mainly) European agroecosystems. Starting with non-standardized studies on the effects of pesticides on the sub-individual level, we compile the results of standard laboratory tests performed following OECD and ISO guidelines as well as those of higher-tier studies (i.e., semi-field and field tests). The number of comparable test data is still limited, because tests with enchytraeids are not a regulatory requirement in the European Union. While focusing on the effects of pesticides, attention is also given to their interactions with environmental stressors (e.g., climate change). In conclusion, we recommend to increase the use of enchytraeids in pesticide risk assessment because of their diversity and functional importance as well as their increasingly simplified use in (mostly standardized) tests at all levels of biological organization