Explore the vast range of titles available.

The global decline of freshwater mussels is related with a great variety of factors, including the introduction of invasive species. However, the possible effects of other invasive bivalves, such as the Asian clam Corbicula fluminea (Müller, 1774), remain mainly unknown and highly speculative with very few manipulative experiments addressing this issue. In this study, field and laboratory experiments were conducted to assess the possible negative effects of C. fluminea on the native freshwater mussel Unio delphinus Spengler, 1783. Growth, physiological condition, and the locomotor activity were assessed in U. delphinus at increasing C. fluminea density. U. delphinus exhibited lower growth, lower physiological condition, and higher locomotor activity at higher C. fluminea density, which may suggest that this unionid is negatively affected by C. fluminea and may be displaced to less favorable habitats. Although we were not able to establish the main mechanism(s) responsible for these results, possibilities include competition for food resources, competition for space which may result in mussel displacements and/or changes in microhabitat features as a result of bioturbation activities, and production of feces and pseudofeces by C. fluminea.

The objective of this study is to provide an updated account of the distribution history of two invasive molluscs, Corbicula fluminea and Dreissena polymorpha, both in Europe and worldwide. In addition to this, the study also intends to review their ecological requirements to gain a better understanding of their invasive potential and distribution dynamics. Specifically, the study focuses on updating the distribution and ecological characteristics of these freshwater bivalves in the lower sector of the Danube River and the lakes of the Danube Delta. The purpose is to better understand their invasive and distribution dynamics and to develop effective measures to limit their spread in the future. To achieve this, environmental proxies such as sediment particle size and Total Organic Carbon (TOC) concentrations were used to assess their tolerances. However, the results did not show a significant correlation between the densities of these bivalves and the analyzed environmental parameters. Despite this, the species were found in high densities and formed well-developed benthic communities in some stations. The study contributes to the understanding of the invasiveness of these bivalve species and their distribution range dynamics. Nonetheless, further investigation is required to fully comprehend the role of environmental parameters in their distribution. The study covers the period between 2010 and 2020 and focuses on the lower Danube River sector and Danube Delta.

Despite the full attention of malacologists to the study of Corbicula clams, stimulated mainly due to their high invasive potential and unique breeding system, studies based on an integrative taxonomic approach to identify various invasive lineages of this genus in European Russia are still limited. Our fieldwork was conducted in the Don, Volga, and Caspian Sea basins. In total, four distinct morphotypes belonging to the European forms R, Rlc, S, and “Int” of Corbicula clams were distinguished. According to our molecular genetic data, two Corbicula lineages, relevant to the nominal species Corbicula fluminea and C. fluminalis, can be defined. We observed a discrepancy between mtDNA haplotypes and morphological features for all individuals that were sampled from the Don and Kura Rivers. Identified mismatch may be due to the androgenetic reproduction of Corbicula that leads to cytonuclear inconsistencies. The 28S rRNA polymorphism in C. fluminea and C. fluminalis from studied localities was recorded. This occurrence is perhaps due to hybridization events between forms R, S, and Rlc. The biogeographic origins of Corbicula invasive lineages are discussed. Corbicula fluminalis (FW17, form S) has been detected for first time in the native range, namely in Azerbaijan, Tajikistan, Turkey, and Myanmar. We assume that the invasion of C. fluminalis into reservoirs and watercourses of the Caspian Sea basin (Republic of Dagestan and Stavropol Krai of Russia) was from Western Asia and Transcaucasia, and the introduction of C. fluminea to the Don and Volga River basins was from unspecified European countries.

Aim Environmental DNA (eDNA) is a rapidly emerging methodology with important applications to environmental management and conservation. However, the effects of stream flow or discharge on eDNA have been minimally investigated in lotic (stream and river) environments. In this study, we examined the role of stream flow on eDNA concentrations and detectability of an invasive clam (Corbicula fluminea), while also accounting for other abiotic and biotic variables. Location Illinois, United States of America. Methods We used a longitudinal study over a year in two streams, as well as a seasonal study (summer, autumn) in eight streams, to investigate the effects of variable stream flow on eDNA concentrations and detectability. We used linear mixed‐effects models to assess the influence of various factors on eDNA concentration and occupancy models to make predictions on how seasonality can influence eDNA detection. Results We found higher stream flows decreased eDNA concentrations, and floods produced false negatives or non‐detections at locations where C. fluminea was relatively common. In addition, we found concentrations and detectability of C. fluminea eDNA to be higher in summer than in autumn. Main conclusions We found that stream flow dilutes eDNA concentrations, which may have serious implications for the detection of low abundance organisms. Managers and practitioners applying eDNA for rare species should seek to sample at low or base stream flows when feasible, and future studies should investigate whether our findings here are consistent for other taxa and lotic ecosystems.