Search Results (51)

Freshwater oligochaetes, belonging to the class Oligochaeta, are vital components of aquatic ecosystems globally, contributing significantly to nutrient cycling, sediment dynamics, and overall ecosystem function. Despite their ecological importance, freshwater oligochaetes in Korea remain relatively understudied compared to other aquatic organisms. This study aimed to enhance our understanding of the diversity and ecological roles of freshwater oligochaetes in Korean aquatic ecosystems. We identified nine species across six genera and two subfamilies from samples collected from various freshwater environments in Korea. This research contributes valuable taxonomic knowledge and highlights the ecological significance of freshwater oligochaetes in Korean aquatic ecosystems. Full article

The responses of benthic fauna to channel modifications of mountain rivers by low-head barriers are poorly understood. The study aimed (1) to estimate the impact of two different low-head barrier types: concrete sills and block ramps, on Oligochaeta and Trichoptera communities in two small Carpathian rivers (Porębianka and Mszanka) in southern Poland, and (2) to determine changes in these communities in the mountain Porębianka River after 50 years by comparing current data with historical data. Both types of channel modifications led to a transformation from lotic to more lentic habitats. The research shows that habitat conditions and induced bed siltation greatly influenced the studied communities. In both rivers, the taxa richness and dominant taxa of Oligochaeta and Trichoptera were similar, alongside similar species compositions of Trichoptera. However, the river with the lower bed siltation rate had a higher Trichoptera density and a greater diversity in their density among habitats. After 50 years, the taxonomic richness of Oligochaeta and Trichoptera remained similar, unlike the considerable shift in their species compositions. Many species typical of mountain rivers have been replaced by species more tolerant to siltation, characteristic of lowland rivers. The family Tubificidae (Oli-gochaeta) and the genus Hydropsyche (Trichoptera) became dominant in both rivers in the early 2020s. Additionally, the functional feeding group (FFG) of Trichoptera changed considerably. Oligochaeta and Trichoptera communities serve as valuable indicators for moni-toring the environmental changes in these ecosystems. Full article

Ecological integrity, encompassing physical, chemical, and biological aspects, is crucial for sustaining ecosystem service functions and stability. As the largest freshwater lake in China, the ecological integrity of Poyang Lake has attracted much attention due to the over-exploitation of its water resources in recent years. In this study, several biological and water quality surveys on water ecological conditions were carried out at 11 sampling points of Poyang Lake from 1998 to 2022, and the ecological health of Poyang Lake was evaluated by use of the O/E (Observation/Expectation) model and the chemical–biological index method according to the status of the water quality and the structure of the benthic fauna in the four seasons, respectively. The results showed that the benthic community structure is simple, and the biodiversity is low, which is mainly dominated by Insecta in Arthropoda and Oligochaeta in Oroidea, accounting for 84.3% and 42.4%, respectively; the results of the O/E index evaluated under the threshold of probability of capture ≥ 0.5 showed that the health grade of all sections was sub-healthy or average, which was consistent with the results of the chemical–biological composite index evaluation. The dual evaluation method of the O/E model and chemical–biological composite index adopted in this study integrates more than twenty years of long-time scale data; this method combined with long time scale data has not been studied before, and its advantage is that it can more objectively show the change in the ecological situation of Poyang Lake for many years. The results of the present study could provide a theoretical basis and technical support for the evaluation of lake water environment quality. Full article

Dam construction disrupts river continuity, and alters hydrological dynamics and the distributional composition of aquatic organisms. Understanding the spatial distribution of aquatic communities following dam construction is crucial for the effective management and restoration of riverine ecosystems. This study focused on the macroinvertebrate community of the Hanjiang River during the low-flow period, and explored the relationship between water quality indices and bioindicators. The results revealed significant changes in both the composition and functional feeding groups (FFGs) of macroinvertebrate communities from the upper to the lower reaches of the river. Compared to the natural reach, the dam-affected reaches showed a decrease in the number of sensitive taxa of Ephemeroptera, Plecoptera, and Trichoptera (EPT), and an increase in the number of moderate tolerant taxa of Gastropoda and tolerant taxa of Oligochaeta. The collector-gatherers (CGs) dominated in the Hanjiang River. In the dam-affected reaches, the relative abundance of collector-filterers (CFs) and shredders (SHs) appeared to decrease, while that of scrapers (SCs) and CGs increased. Principal component analysis (PCA) revealed that latitude and dissolved oxygen (DO) played a crucial role in the spatial pattern of macroinvertebrates, and the biotic index (BI) and family biotic index (FBI) more accurately reflected the level of organic pollution in the Hanjiang River. The findings of this study are valuable for ecological management and biodiversity conservation following dam construction. Full article

Currently, on a global scale, integrated taxonomical works, by incorporating the molecular approach and traditional taxonomic methods have gained acceptance. Recently, Lone et al. (Diversity 2022, Phylogenetic Relationships in Earthworm Megascolex Species (Oligochaeta: Megascolecidae) with Addition of Two New Species) studied eleven Megascolex species (including two new species) from the Western Ghats biodiversity hotspot region of the Kerala state, India, by incorporating the integrated methods. The analysis of the results provided in Lone et al. indicated several discrepancies and shortcomings. They have overlooked or incorrectly described many key characters used in the Megascolex species identification and provided faulty figures. Apart from these, the paper had many factual as well as systematic errors. In this comment, based on the data provided by Lone et al., we critically reviewed their work, citing the errors and defects so as to help them to avoid similar issues in their future works and to obviate further confusions in the field of earthworm taxonomy. Full article

Forest litter can decompose faster at home sites than at guest sites (home-field advantage, HFA), yet few studies have focused on the response of the HFA of native plant decomposition to the presence of invasive plants. We loaded the dry leaves of native Neosinocalamus affinis (decomposition resistant) and Ficus virens (more easily decomposable) leaves into litterbags with and without invasive Alternanthera philoxeroides, and incubated these litterbags at N. affinis and F. virens sites at the edge of the forest. The results showed that positive HFA effects with litter mass loss were at least 1.32% faster at home sites than at guest sites. The addition of A. philoxeroides reduced the mean HFA of N. affinis litter and increased that of F. virens litter. The HFA index without A. philoxeroides was significantly higher than that with A. philoxeroides. Soil faunal abundance colonized at home sites was always higher than that colonized at guest sites. Compared with the F. virens site, the abundance of Collembola, Arachnida, Formicidae and Lepismatidae at the N. affinis site was significantly higher compared to the F. virens site, while the abundance of Isopoda, Oligochaeta, Nematoda and Dermaptera was significantly lower. Our results indicate that invasive plants may regulate HFA effects by promoting the decomposition of native plants and increasing fauna abundance. Particularly, soil fauna groups play a very important role in this process. Our findings help us to re-understand the role of invasive plants in material cycling and energy flow in the context of achieving carbon neutrality goals. Full article

The evaluation of the ecological consequences of anthropogenic stressors is a critical challenge in the management of the environment. Multimetric indices (MMIs) are one of the biomonitoring tools that have been widely explored to assess the ecological health of riverine systems globally, as MMIs have proven to be extremely effective, owing to their ability to incorporate data and information from both structural and functional assemblages of organisms and the entire ecosystem. Currently, there are very few MMIs developed in Nigeria to assess the ecological health of riverine systems, and none of the MMIs was developed for river stations draining urban and agricultural catchments. In order to close this gap, we developed and validated a macroinvertebrate-based MMI for assessing the ecological health of river systems in the Niger Delta area of Nigeria draining urban and agriculture catchments. Furthermore, we also compared the effectiveness of both continuous scoring and discrete systems for the development of MMI. Physico-chemical variables and macroinvertebrates were collected from 17 well-marked out stations that spread throughout 11 different river systems. The stations were classified into three categories based on the degree of impact: least-impacted stations (LIS), moderately impacted stations (MIS), and heavily impacted stations (HIS). Sixty-seven (67) candidate macroinvertebrate metrics were potentially tested, and only five metrics were deemed significant and ultimately retained for integration into the final Niger Delta urban–agriculture MMI. The following five metrics were chosen to remain in use for the MMI development: Chironomidae/Diptera abundance, %Odonata, Margalef index, Oligochaete richness and logarithmic-transformed relative abundance of sprawler. Notable performance rates of 83.3% for the least-impacted stations and 75% for the moderately impacted stations were found during the index’s validation using a different dataset. However, for the stations that were most affected (i.e., the HIS), a 22.2% performance rate was noted. The Niger Delta urban–agriculture MMI was adjudged to be suitable as a biomonitoring tool for riverine systems subjected to similar combined stressors of urban and agricultural pollution. Full article

The presence of microplastic particles in agroecosystems has profound implications for soil quality, crop yield, and soil biota. Earthworms are widely recognized as valuable soil bioindicators due to their abundance, fast reproduction, and easy manipulation. The aim of this study was to observe Eisenia fetida avoidance behavior and changes in biomass and mortality rate in soil samples spiked with polyethylene microplastic particles. Three types of soil sampled from the agricultural fields (“Banat 1”, “Banat 2”, and “Bačka”) were tested, as well as three microplastic concentrations (0.1, 0.2, and 0.3%). The calculated avoidance percentages ranged from 18.67% for “Banat 1” and 23.70% for “Banat 2” to 27.40% in the case of “Bačka” soil samples. Generally, E. fetida specimens avoided the sections with plastic in all bioassays: 38.42% of the earthworms were in the chamber section that contained microplastics, as opposed to 61.58% in the control section. The changes in the earthworms’ post-test biomasses were directly proportional to the number of surviving earthworms, with the highest loss in “Bačka” soil samples with 0.3% MPs (−53.05%). The highest mortality rate (46%) was noted in “Bačka” soil samples spiked with the highest concentration of microplastic particles. Full article

A toxicogenomic approach was used for toxicity evaluation of arsenic in the aquatic environment, and differential gene expression was investigated from 24 h and 96 h water-only acute toxicity tests with the aquatic oligochaete, Tubifex tubifex (Annelida, Clitellata). Several toxicological endpoints (survival and autotomy) of the oligochaete and tissue residues were measured, and dose-response modelling of gene expression data was studied. A reference transcriptome of the aquatic oligochaete, T. tubifex, was reconstructed for the first time, and genes related to cell stress response (Hsc70, Hsp10, Hsp60, and Hsp83), energy metabolism (COX1), oxidative stress (Cat, GSR, and MnSOD), and the genes involved in the homeostasis of organisms (CaM, RpS13, and UBE2) were identified and characterised. The potential use of the genes identified for risk assessment in freshwater ecosystems as early biomarkers of arsenic toxicity is discussed. Full article

Nanobiomaterials (NBMs) have tremendous potential applications including in cancer diagnosis and treatment. However, the health and environmental effects of NBMs must be thoroughly assessed to ensure safety. Fe₃O₄ (magnetite) nanoparticles coated with polyethylene glycol (PEG) and poly (lactic-co-glycolic acid) (PLGA) were one of the focus NBMs within the EU project BIORIMA. Fe₃O₄ PEG-PLGA has been proposed to be used as a contrast agent in magnetic resonance imaging for the identification of solid tumors and has revealed low cytotoxicity in several cell lines. However, the effects of Fe₃O₄ PEG-PLGA have not been assessed in terrestrial environments, the eventual final sink of most materials. In the present study, the effects of Fe₃O₄ PEG-PLGA and its precursor, (un-coated) Fe₃O₄ NMs, were assessed in soil model invertebrates Enchytraeus crypticus (Oligochaeta) and Folsomia candida (Collembola). The endpoints were survival, reproduction, and size, based on the standard OECD test (28 days) and its extension (56 days). The results showed no toxicity for any of the endpoints evaluated, indicating that the NBM Fe₃O₄ PEG-PLGA poses no unacceptable risk to the terrestrial environment. Full article

This taxonomic study investigates marine tubificids, with a focus on the genera Smithsonidrilus, Heterodrilus, Limnodriloides, and Tubificoides and presenting a new species, Heterodrilus koreanus n. sp., discovered in the around Ulleungdo and Dokdo Islands in the East Sea of the Republic of Korea. The new species, Heterodrilus koreanus n. sp., is characterized by a very long and slender atrium with prostate glands attached to the ventral side, with indistinct ducts and large round ampullae in the spermathecae. The four recorded species are: H. pentcheffi Erséus, 1981, Limnodriloides anxius Erséus, 1990, Smithsonidrilus exspectatus Erséus, 1993, and Tubificoides heterochaetus Michaelsen, 1926. This study not only enhances our comprehension of the intricate morphology within these genera but also contributes to the broader understanding of marine oligochaetes, particularly in the Korean marine ecosystem. Full article

The mountain forests of the Northwestern Caucasus represent unique refugia for the native biodiversity of flora and fauna. Endemic species are also preserved among soil invertebrates, including the group of earthworms, which are important ecosystem engineers. This study assesses the spatial distribution of the endemic anecic species of earthworms Dendrobaena nassonovi nassonovi Kulagin, 1889 in deciduous, coniferous–deciduous, small-leaved, and conifer forests of the Northwestern Caucasus (a total of 1028 geographical points were surveyed, of which the species was found in 185 points) based on our own field data by modeling the current potential areas using the Maxent software. The D. n. nassonovi potential area maps show a high probability of the species inhabiting mid- and high-mountain forests of the Northwestern Caucasus and being confined to mixed coniferous–deciduous and beech forests. The optimum soil and climatic parameters, as well as a lack of large-scale business operations in the mid- and high-mountain forests, make it possible for these ecosystems to remain suitable refugia, in particular for the endemic anecic species of Caucasus earthworms D. n. nassonovi. Full article

The aim of our study was to detect the actual distribution of oligochaete species and to identify their ecological differentiation with respect to environmental factors: altitude, temperature, oxygen concentration, conductivity, total organic carbon, and waterbody type. Although widespread, differentiation of oligochaete communities in four waterbody types and altitudinal groups can be observed through alpha and beta diversity. Their differences were analyzed using MANOVA, while the ecological preferences of species were presented with logistic Gaussian regression analyses. The highest number of the species of Oligochaeta was recorded in oligochaete communities in medium and large rivers. Total beta diversity decreased with the decreasing of waterbody size, the increasing of size of the substrate particles, river flow velocity, as well as altitude. Communities from small mountain rivers and streams and large and medium rivers with coarser substrate differed from other oligochaete communities. When coarser substrate was prevalent in smaller and medium rivers, a domination of a certain family was observed: Lumbriculidae (>800 m a.s.l.), Propappidae and Enchytraeidae (500–800 m), and Naididae (<500 m a.s.l.). Common species of Oligochaeta, with significantly overlapping ranges in running waters in Serbia, still show a clear grouping with respect to preference for certain types of waterbodies. Full article

This work continues a series of publications on the diversity of the main groups of invertebrates found through the investigation of meiobenthic communities in various inland waterbodies in central and southern Vietnam. Here, a checklist of oligochaetes and aeolosomatids (the annelid worms) discovered for the period 2010–2021 is presented, as well as data on the structure and abundance of their populations found in the country, ecology, local and global distribution, and, where necessary, taxonomic, morphological and other comments. In total, 71 representatives of the species and supra–species ranks from 3 families and 17 genera are listed. In total, 39 representatives were identified to the species level. During the present research, 2 species new to science were discovered and described in previously published works. This paper reports 9 more forms that need further study and may belong to still undescribed species. In addition to the new and still-unidentified species, the checklist reports about 30 more members of species and supra–species ranks that were recorded in Vietnam for the first time. Based on new and previously published data, the currently known diversity of aquatic oligochaetes and aeolosomatids in Vietnam is estimated at approximately 100–113 and 8–9 representatives, respectively. It is shown that members of the family Enchytraeidae remain practically unexplored in the waterbodies of the region. The subfamily Tubificinae and the family Aeolosomatidae also continue to be relatively poorly studied here at the species level. Full article