Morphology-based species identification may not be accurate and necessitates extensive taxonomic knowledge. Regarding Heteranthera reniformis Ruiz and Pavon, an invasive alien species in Japan, it is difficult to find appropriate information on molecular data. DNA barcoding is a convenient method of identifying species based on the nucleotide diversity of conserved sequences. In...
Most research on lotic food webs has focused on reach-scale webs, whereas research on the structure and system openness of lotic food webs has not focused on the microhabitat scale. In forested streams, plant litter from riparian vegetation accumulates as discrete patches, forming a microhabitat for macroinvertebrates. We primarily aimed to determine the relative trophic position...
Environmental DNA (eDNA) analysis using lake sediment cores can be used to assess populations, dynamics, and historical changes in ecosystems and environments, based on the DNA composition of micro-organisms and plants. While this method has shed light on past environments, a more detailed understanding of past ecosystems requires targeted sediment core eDNA analysis focusing on...
Lake browning, i.e., a gradual and long-term increase in the water colour, is a recognized and topical water quality problem that has received much less attention in water protection than eutrophication. Thus, new bioindicators that respond to environmental stress are needed to monitor lake browning. Recent study suggests that the chlorophyll content of macrophytes is a promising...
The study of dragonfly exuviae is an effective tool that provides noninvasive insight into many aspects of their population biology or interspecific interactions with their predators or prey. Here, we analysed morphometric parameters of the exuviae of five dominant dragonfly species in three central European ponds characterized by different fish populations and generated a robust...
Recently, the Brachionus calyciflorus species complex was divided into four nominal species: B. calyciflorus sensu stricto (s.s.) Pallas, 1766; Brachionus dorcas Gosse, 1851, Brachionus elevatus Michaloudi et al., 2018, and Brachionus fernandoi Michaloudi et al., 2018 based on the results of both morphological and molecular investigations. We applied this systematic approach to B...
Seasonal stratification hinders the ventilation of hypolimnion water, leading to the formation of an anaerobic benthic layer in shallow lakes. This study quantifies the processes of hypoxia formation and recovery in Lake Kasumigaura, Japan, under conditions of developing metalimnion during early summer, specifically from early May to mid-July 2022. We conducted direct...
Global warming directly and indirectly affects the biology and ecology of aquatic insects. Chironomids are ubiquitous on the earth and are suitable for systematic analysis of the warming effect on insects. Here, we measured the survival rate for the fourth-instar larvae of seven Chironomus species at different temperatures. The mid-temperature for survival after 1-h temperature...
Organism size is considered a master trait influencing virtually every aspect of life, but the underlying mechanisms of phenotypic variation are still poorly understood. This study examined the valve size (length, height, width) of an ostracod species (Cyprideis torosa) collected from different lakes of the Mansfeld Lakes (ML), Central Germany. Size variability were investigated...
The redox conditions in the littoral limnic sediments may be affected by the penetration of plant roots which provide channels for oxygen transport into the sediment while decomposition of the dead roots results in consumption of oxygen. The goal of this work was to study the impact of environmental parameters including penetration of roots of Cyperus articulatus L. into the...
The responses of assemblages and ecosystems to river intermittency are often considered on large spatial scales, such as those associated with the Köppen climate classification. However, river intermittency may naturally occur even in humid regions, and the effects may differ from those where intermittency occurs throughout the area. This study aimed to examine the differences in...
Freshwater invaders threaten both natural ecosystems and human activities. An invasive freshwater sponge Heterorotula multidentata (Weltner, 1895) has been found for the first time in continental waters of Europe (Spain). It is a species native to Australia and New Zealand, from which it spread to Japan, being considered invasive. The species has been found in water intake grids...
In floodplains, which are highly modified and less inundated, trees are expanding, thus raising concerns regarding their impact on freshwater organisms. We analyzed the relationship between forest expansion and the change in Odonata (dragonflies and damselflies) assemblage over an extended period of time in the floodplain with ponds of the Kiso River, central Japan. In the 1970s...
This contribution presents the first record of the invasive non-native red swamp crayfish Procambarus clarkii (Girard, 1852) in Greece and the Balkans. The crayfish was found during a fish monitoring expedition in the lower reaches of the Vosvozis River, near the city of Komotini, Thrace (northeastern Greece). The finding of P. clarkii in Greece expands the southernmost...
Japanese giant salamander (Andrias japonicus) is one of the largest amphibian species in the world and an iconic species in Japan. However, as its distribution has recently declined across the country, rapid and extensive monitoring of the distribution is urgently needed for its efficient conservation. Here, we used environmental DNA (eDNA) analysis to assess the Japanese giant...
Dark artificial surfaces reflecting highly and horizontally polarized light usually have negative effects on polarotactic aquatic insects detecting their habitats by the horizontal polarization of water-reflected light. This ecologically disadvantageous phenomenon is called polarized light pollution. We have observed that the water between the concrete walls of a harbour of the...
Closed-circuit hypolimnetic withdrawal and treatment systems (HWTS) represent a novel lake restoration technique in which nutrient-rich near-bottom water is pumped through a treatment system and returned to the same lake. However, the design of such systems is not yet standardized and routing of effluent waters must be planned carefully to minimize the risk of adverse water...
Permanent phosphorus (P) burial in sediment regulates lake trophic state over long timescales, but the controls on P burial are only partially understood. A diversity of biogeochemical settings may be found in lake sediments, which may have a strong impact on the processes controlling P burial from one location to another. Here, we investigate early diagenesis of P in three...
Biomass estimation offers insight into aquatic ecosystem processes and represents a powerful tool for measuring biomass in communities. However, the accuracy of this estimate depends considerably on the sample preservation method and biological traits of species. We quantified the effect of commonly used preservatives (70% ethanol, 4% formaldehyde, freezing), preservation time...
Glacier surfaces are the most biologically productive parts of glaciers with a variety of organisms and habitats. However, distinctiveness of habitats and communities of dominant invertebrate consumers on the ice surface is poorly documented. We focused on dominant consumers in three supraglacial (on the glacier surface) habitats on the alpine glacier Forni – cryoconite holes...
Vertical transport caused by mixing is essential for understanding physical processes in lakes. However, mixing processes in shallow lakes are not well understood because of the lack of turbulence measurements. This study presents observations of vertical mixing and oxygen flux in a shallow lake, Lake Kitaura of the Lake Kasumigaura continuous lake system, which is located along...