The Enchytraeidae (Oligochaeta) of streams of Southern England (original) (raw)
Two new freshwater enchytraeid species (Oligochaeta) from the Italian Alps
Italian Journal of Zoology, 2010
Two new species found in high mountain waters of Italy representing the family Enchytraeidae are described. Cernosvitoviella longiducta n. sp. is clearly differentiated from all species in this genus by its exceptionally long sperm duct. Cognettia valeriae n. sp. belongs to a group of species having more than three pairs of pharyngeal glands and male pores situated in segment X, but differs from other species in this group by the shape of spermathecae and the well-developed seminal vesicles.
Annales de Limnologie - International Journal of Limnology, 2004
However, these works concerned almost exclusively soil inhabitants. Enchytraeids from freshwater environment, especially from running waters, were rarely studied (Kasprzak 1976, Dumnicka & Boggero in press), though they are common and sometimes abundant in Alpine streams (Malard et al. 2001, Maiolini & Lencioni 2001). During the realization of the HIGHEST program (Health and Integrity of Glacial Headwater EcoSystems in Trentino), a detailed ecological study of alpine headwater streams, benthic macroinvertebrate samples were collected in glacial and non-glacial streams between 1985 and 2600 m a.s.l., within the two river catchments : Noce Bianco (NB) and Careser (CR), situated in Stelvio National Park, Trentino. A new species of Cernosvitoviella N. & C. 1959 was found and is described in this paper. Description of the species Holotype: whole mounted specimen in Canada balsam.
Hydrobiologia, 2004
Data from 24 water management districts and the rivers Rhine and Meuse in the Netherlands were used to study geographical distribution, relative occurrence, and environmental requirements of 76 aquatic oligochaetes (families Tubificidae, Naididae, and Lumbriculidae) (Annelida, Clitellata). Approximately 50% of the 76 species that occur in the Netherlands are uncommon, rare, or very rare. The other half of the species are common, very common or abundant. The abundant species are: Stylaria lacustris, Ophidonais serpentina, Limnodrilus claparedeianus, Limnodrilus hoffmeisteri, and Lumbriculus variegatus. With the exception of several brackish water species (those restricted in distribution to water management districts close to the sea that are influenced by salt water influx) and specific running water species (restricted mainly to the eastern part of the Netherlands), most of the species occurred throughout the whole Netherlands. The species distribution was related to environmental variables using ordination. In general, species distribution was correlated with either large waters with high chloride and phosphorus concentrations and a high hydrogen ion concentration (as pH), or with small forested (running) waters in more natural (undeveloped) areas that occasionally become intermittent. Vegetation cover was positively correlated with several swimming species in the family Naididae. While the distribution of aquatic oligochaetes in some families occurring in the Netherlands is known to some extent, the occurrence and distribution of rare and small taxa, particularly those that are difficult to identify taxonomically, is virtually unknown. Some of the rare oligochaete taxa, especially those associated with unique habitats, have received only cursory attention. Also in the data studied, the observations of the more rare species were too few to draw conclusions. To improve our knowledge of oligochaete distribution in the Netherlands, additional research should focus on rare species associated with special habitats and water types (natural areas) and those taxa in poorly known families. The standardisation of sampling and processing methodologies, particularly the use of nets and sieves with fine-meshed screening, will ensure the collection of the smaller species of oligochaetes. Subsequently, oligochaetes should be identified to species level by experienced taxonomists trained in oligochaete identification. Finally, many aquatic oligochaete species are identifiable only when sexually mature and therefore the time of year in which samples are collected is critical to the accurate representation of true oligochaete diversity at any given site. For analysing the relation between species and environmental variables the best option is to use composite data from spring and autumn.
Springer eBooks, 2001
In most soft-bottomed, lowland streams in the Netherlands discharge regimes largely follow the precipitation pattern. Winter discharges are higher and much more dynamic then summer discharges, although rain storms throughout the year cause unexpected peak flows. Minimal precipitation, reduced stream flow and droughts can occur during the summer months. Lowland stream habitat, particularly in The Netherlands, is hydrologically dynamic, with substrates frequently moved or disturbed. Differences in discharge patterns in Dutch soft-bottomed lowland streams are expected to affect distribution patterns of macroinvertebrates and thus oligochaetes. Ten small to medium sized lowland streams, differing from one another in hydrological regime, were studied. Five major habitats in each stream were assessed on three occasions over a 15-month period. Each habitat sampled with a micro-macrofauna shovel; during each sampling period, several environmental parameters, especially hydrological and substrate parameters, were measured. Ordination (CANOCO) (Ter Braak, 1989) and statistical tests (chisquared test) (Lindgren & McElrath, 1970) were used to determine the major oligochaete distribution patterns between streams as well as between habitats within each stream. Each stream was characterized by its oligochaete assemblage; general distribution patterns and individual oligochaete-substratum relationships were documented. Hydro-morphological parameters together explained the differences in major distribution patterns. Preferences of oligochaetes for specific structural habitats are discussed.
The effect of drought on Oligochaeta communities in small woodland streams
Oligochaeta communities were studied in four streams inflowing Lękuk Wielki lake and from the outflow of this lake (NE Poland) during 1997-1999. Twenty five taxa of oligochaetes were identified, representing aquatic (Tubificidae, Lumbriculidae), semi-aquatic (some Enchytraeidae and Lumbricidae) and soil (Lumbricidae, some Enchytraeidae) families. The occurrence of Naididae was limited to the outflow of the lake. After a drought period the densities of oligochaetes were the highest, diminishing during the permanent flow period. The composition of the oligochaete fauna in the studied small, drying streams depends on fauna composition in the lake and surrounding soil as well as the inflow from shallow subterranean waters, therefore species with different ecological requirements appear simultaneously.
Micro-distribution of oligochaetes in a soft-bottomed lowland stream (Elsbeek; The Netherlands)
Aquatic Oligochaetes, 1999
This study focuses on a low-gradient, soft-bottomed stream which shows strong fluctuations in discharge, partly natural (i.e. due to rainfall) and partly due to agricultural land-use. This dynamic discharge pattern causes silt deposition between discharge peaks which in turn cause the silt to be washed out. This process occurs independently from the height of the peak. The main substrate in the stream is quite homogeneous fine sand. Twenty-three species of oligochaetes were found. Their distribution and abundance varied with season and substrate. Mature tubificids and Lumbriculus variegatus occurred throughout the year. Stylodrilus heringianus occurred in winter and spring. Different naidids occur in different seasons, though half of the species can be collected all year. The micro-habitat of three tubificids, one lumbriculid and eight naidids were be identified. A high number of oligochaete species coexisted in a small stretch of the stream due to a separation in micro-habitat in space and time. The temporal variation in distribution was due to season. Particle size, the mineral and organic component of the substrate, and position in the stream bed influenced the spatial distribution of species. Temporal and spatial distribution of oligochaetes can not be separated.
Aquatic oligochaetes associated with bryophytes in an Atlantic Forest stream
Biota Neotropica, 2013
There are few reports in the literature about the colonization of benthic macroinvertebrates on bryophytes. The aim of the present study was to analyzed the oligochaetes established on bryophytes adhered to stones in a first-order stream. The collections were carried out in an Atlantic Forest fragment area during the dry and rainy seasons. We identified 15 taxa from a total of 422 oligochaetes specimens, of which the most abundant were Pristina sp.1, Enchytraeidae and Pristina jenkinae. Unlike other habitats, where the abundance of macroinvertebrates tends to be greater in the dry season, we did not find any significant differences in the abundance, richness, composition and diversity between the two periods. The results of this study indicate that bryophytes are possible areas of refuge for oligochaetes in periods of faster water flow.
Enchytraeids (Oligochaeta, Enchytraeidae) of Warsaw and Mazovia
Memorabilia Zoologica 34, 1981
The study on the species composition and abundance of the Enchytraeidae living in Warsaw was carried out on 24 plots in 1974-1977. In this period 22 species were recorded of eight genera, among which the genus Fridericia Mich, was most numerous (Tab. 1). The highest number of species occurred in the soils of parks, green areas of housing estates, and lawns in the centre of the town. Four geographical groups of species have been distinguished: European (50.0%), Holarctic (37.5%), cosmopolitan (= geopolitan) (8.3%), and Palaearctic (4.2%) (Tab. 2). No association of individual species with particular habitats was found. But the numbers of species and individuals were considerably higher on the plots located under or near the canopy of trees and shrubs. All the urban plots were generally characterized by considerably lower numbers of Enchytraeidae than other anthropogenic habitats, especially agroecosystems. As far as the origin of urban Enchytraeidae is concerned, local species predominate, with large ranges and high adaptability to changing environmental conditions.
Achaeta unibulba sp. n., a widespread European species (Oligochaeta, Enchytraeidae)
2005
Achaeta unibulba sp. n. is described from a variety of terrestrial habitats in Europe. The new species is similar to a group of species around A. eiseni Vejdovský, 1878, having bottle-shaped glands (= setal follicles) dorsally and ventrally, the latter being only slightly smaller. Its main distinguishing characters are the fused penial bulbs forming a large roundish body at the ventral midline, the absence of accessory penial glands, the arrangement of clitellum glands, the presence of a large gland at the orifice of the spermathecae, an oesophageal appendage in V without canal leading to pharynx, and the presence of three pairs of preclitellar nephridia. The species occurs in slightly acid to neutral soils. It was found in mineral horizons of mull humus forms as well as in fen peat.