Benthic Invertebrate Communities Research Articles

The nearshore aquatic environment of eastern Lake Erie: A thirty-year perspective from a monitoring station

Abstract Dreissenid mussels arrived at the Waverly Shoal located above the inflow of the Niagara River in 1989, initiating marked changes in the water and sediment chemistry, and benthic invertebrate community composition at an Ontario Ministry of the Environment, Conservation and Parks monitoring station. Here we examine change in the nearshore of eastern Lake Erie until 2019, inferred from monitoring at this station. Dreissenid numbers peaked in 1991, exceeding 200,000 individual m-2, and remained above 20,000 individual m-2 until 2004 after which numbers progressively declined. In 1993, the population transitioned from mixed Dreissena polymorpha and D. bugensis, to D. bugensis in subsequent years. The decrease in particle size and increase in organic content of surficial sediment which began the year after mussel arrival has persisted until present time. The low concentrations of trace metals and PAHs at the station increased slightly after the physical alteration in bed sediments and has either not changed or declined. After an initial increase in Secchi depth, water clarity changed little over post invasion years, with prevailing moderate water clarity interspersed with periods of bed resuspension and high turbidity. Calcium concentration in the water column, which fell dramatically after the arrival of dreissenids, has gradually increased in recent years. Chlorophyll a and total phosphorus levels indicating oligo-mesotrophic conditions have not varied systematically over the years, other than a modest decline in chlorophyll a after dreissenid arrival. Benthic invertebrate assemblages have gone through multiple alterations, with shifting abundance of amphipods, oligochaetes, chironomids, gastropods and sphaeriids attributed to invasive species rather than the physical environment. Collectively, the data suggests the nearshore ecosystem has shifted in benthic productivity and trophic transfers mediated by the benthos and invasive species, with water and sediment quality appearing to not vary beyond the range driven by inherently fluctuating physical conditions.

The role of seedbanks and hyporheic refuges in supporting benthic invertebrate community resistance and resilience to dry phases

In intermittent streams, aquatic organisms use various strategies to face dry phases, but the relative contribution of these strategies to persist during dry phase remains unclear. Here, we investigated the in situ persistence of benthic invertebrates in the saturated hyporheic sediments and the “invertebrate seedbank” that persists in dry sediments across six Mediterranean intermittent streams. Taxonomic and functional responses within hyporheic and seedbank assemblages were compared with those in the benthic assemblages under connected flow conditions by combining field and mesocosms data. The dry phase duration in each stream was calculated to assess the responses of hyporheic and seedbank assemblages. Taxonomic composition and abundance-weighted traits related to resistance and resilience to face the dry phase in each assemblage type (benthic, hyporheic, seedbank) were determined. Taxonomic (richness and diversity) and functional (richness and dispersion) metrics were also calculated. We found that seedbank and hyporheic assemblages supported up to 16% and 40% of the benthic taxa, respectively. Only taxonomic and functional richness differed between assemblage types. Contrary to previous research, no clear relationship was established between diversity or the abundance of resistance traits and the duration of dry phase; however, a negative linear relationship was identified between the abundance of resilience traits and the duration of the dry phase. The increase in the frequency and duration of drying events due to climate change will reduce water availability in both saturated and unsaturated streambed sediments, compromising the persistence of aquatic biodiversity in intermittent streams.

A new method for bioassessment of ecosystems with complex communities and environmental gradients

Bioassessment of complex and heterogeneous ecosystems is a challenge when there are multiple, strong, natural environmental gradients; unknown, or spatially varying, mixtures of stressors; and large numbers of taxa with unknown responses to both the environmental gradients and the stressors. Current methods of bioassessment are not designed for use under this set of constraints. To address this gap, we have developed an assessment method appropriate for well-sampled, heterogeneous systems with many taxa. In the bioassessment described below, we model taxa occurrence as a function of natural environmental gradients, then use residual covariance patterns between all pairs of taxa to estimate the impact of human disturbance across sites as a latent construct. The derivation of the method from an underlying causal model allows the metric value at each site and the associated taxa responses to be partitioned into contributions from a set of putative stressors. We apply this method as a case study to the subtidal benthic invertebrate community of Puget Sound, WA (USA) and demonstrate a partial decomposition of the metric values to a set of stressors including sediment organic carbon, nitrogen, metals, and organic pollutants. While this method provides new opportunities to estimate, communicate, and understand the ecological condition of complex, heterogeneous ecosystems, due to the requirement for broad, detailed data to inform its estimates, it will likely be most appropriate for monitoring programs.

Habitat and benthic community correlates of Epeorus longimanus (Ephemeroptera: Heptageniidae) microdistribution in a Colorado, USA, stream riffle

Abstract Little is known about the ecology of early instars of most aquatic insects, particularly their associations with microhabitat (<1 m2) features, such as sediment size distributions, other abiotic parameters, and the overall invertebrate community. This study sought to explore correlations between various biotic and abiotic parameters of a southern Colorado stream and the presence of early instars of Epeorus longimanus (Eaton) (Ephemeroptera: Heptageniidae). A total of 18 samples collected in 2007 and 2013 using a Hess sampler in riffle habitats were used to correlate the size of individuals with biological and abiotic characteristics of the stream, including sediment size, periphyton biomass, entrained organic matter, and the remainder of the benthic invertebrate community, all of which were measured using material from within the sampler. Results from both years showed that early instars of E. longimanus were more likely to be found in areas with smaller sediment sizes, higher live periphyton biomass (but lower overall organic matter), and lower densities of invertebrate predators.

A trait-based approach to assess niche overlap and functional distinctiveness between non-indigenous and native species.

Our understanding of the community assembly processes acting on non-indigenous species (NIS), as well as the relationship with native species is limited, especially in marine ecosystems. To overcome this knowledge gap we here develop a trait-based approach based on the functional distinctiveness metric to assess niche overlap between NIS and native species, using high-resolution data on benthic invertebrate communities in the Baltic Sea. Our results show that NIS retain a certain degree of similarity with native species, but display one or a few singular unique traits (e.g., bioturbation ability). Furthermore, we demonstrate that community assembly processes, including both environmental filtering and limiting similarity affect NIS establishment, but that their effects may be highly context dependent, as illustrated by pronounced spatial patterns in distinctiveness. Finally, our trait-based approach provides a generic framework applicable to other areas and organisms, to better understand and address biological invasions.

Habitat type strongly influences the structural benthic invertebrate community composition in a landscape characterized by ubiquitous, long-term agricultural stress

ABSTRACT The importance of small waterbodies for biodiversity and ecosystem processes has long been neglected in research and policy development. However, because of their heterogeneous characteristics and habitat structures, these waterbodies are biodiversity hotspots for various aquatic and terrestrial organisms, as previously shown for rotifers, aquatic birds, and amphibians. Knowledge of benthic invertebrate community structures in small waterbodies is scarce. Thus, we performed a comprehensive field study of these structures in an agricultural landscape in the northeastern German lowlands. We obtained a dataset containing biological (taxon abundances) and chemical (pesticide residue and nutrient concentration) data as well as data on environmental parameters (e.g., conductivity and habitat type) for 111 samples. The dataset was analyzed using generalized linear models, permutational multivariate analysis of variance, and partial redundancy analysis to understand the relationships among benthic invertebrate communities, agricultural stressors, and environmental parameters. The factor that best explained structural community composition was habitat type. Pesticide and nutrient concentrations were of minor importance in our analysis. Because of the ubiquitous and long-term occurrence of the agricultural stressors, the structural indices used in benthic invertebrate biomonitoring were not sufficiently sensitive to provide information on the main environmental variables that shape macroinvertebrate communities.

Macroinvertebrate traits in Arctic streams reveal latitudinal patterns in physiology and habits that are strongly linked to climate

IntroductionArctic freshwater ecosystems are undergoing rapid environmental transformation because of climate change, which is predicted to produce fundamental alterations in river community structure and function.MethodsWe explored how climate change affects benthic invertebrate communities of Arctic streams by examining patterns of their biological traits along latitudinal and climatic gradients in eastern North America (Canada) and northwestern Europe (Sweden, Norway).ResultsDespite differences in taxonomic composition between continents, we identified similarities in the functional trait niche (FTN) of predominant macroinvertebrate taxonomic groups. Trait composition differed by latitude in eastern Canada, with a predominance of cold-tolerant taxa, tubular body shape, and cased and attached habits at the highest latitudes. Differences in trait composition were evident among ecoregions in Europe, with trait dominance at the highest latitudes that was comparable to North America. There was a similar increase in the relative abundance of cold tolerance and tubular body shape and a decrease in obligate shredders and trait richness with decreasing temperatures across both continents.DiscussionThese patterns are indicative of FTNs that include physiological traits and habits that are advantageous for the low temperatures, short ice-free period, and low riparian vegetation cover at the highest latitudes. We predict that climate change will lead to an increase in functional diversity at high latitudes, as organisms with trait modalities that are currently only found at lower latitudes move northward. However, this change in trait composition will be mediated by the effect of spatial connectivity on dispersal ability, with slower change occurring on Arctic islands. These findings can support modelling of future change in Arctic freshwater assemblages in response to ongoing climate change.

Benthic invertebrate biodiversity enhancement with reef cubes®, evidenced by environmental DNA analysis of sediment samples

Nature inclusive design (NID) is an “eco-friendly” approach to the construction of manmade infrastructure. reef cubes® are patented construction products designed to be used as NID options for marine developments. Artificial reefs can be made with reef cubes® when used either as replacements of or additions to conventional marine manmade structures in marine construction projects. The first long-term, marine research station with reef cubes® is in Torbay, Devon, UK. A goal of the installation, to enhance biodiversity, is assessed here in regards to the benthic invertebrate community, with a novel method of sedimentary environmental DNA (eDNA) analysis. There are two primary aims targeted in this study: firstly to use sedimentary eDNA metabarcoding to assess if the enhancement of invertebrate biodiversity has been achieved and secondly to assess if the reef cubes have a negative impact on the infaunal diversity of exposed sediments in their vicinity. Sediment samples were taken in and away from, the reef cube® test site, in periods before and after their installation. Genetic material in the samples was amplified, sequenced, and amplicon sequence variants (ASVs) assigned to taxonomic ranks. Invertebrate metazoan biodiversity was analysed in terms of taxonomic richness, taxonomic diversity, genetic diversity of ASVs per taxa and species richness of: orders, functional feeding groups and positional lifestyle groups (infauna, epifauna or plankton). A significantly higher biodiversity of invertebrates was found at the reef sites across all measures. Benthic epifauna, suspension feeders and carnivore taxa in particular exhibited higher diversity. Mussels, barnacles, anemones, hydrozoans and copepods were the most distinguishing taxa. Benthic infauna were similarly diverse inside and around the reef cubes® to surrounding sediments. The results suggest that at least for the reef cubes® sampled here the goal of enhancing invertebrate biodiversity at the test site has been achieved. There was no negative effect found on the infaunal diversity in exposed sediments inside and beside the reef cubes®. Application of eDNA analyses to sediment samples represents a promising and efficient method for assessing such ecological goals with the installation of NIDs and artificial reefs.

Stream Habitats and Aquatic Communities in an Agricultural Watershed: Changes Related to a Mandatory Riparian Buffer Law.

Riparian buffers along streams can intercept eroding soils, contaminants, and nutrients, improving stream habitats and increasing the health of aquatic communities. Instream and riparian habitats and fish and benthic invertebrate communities were surveyed in a Minnesota stream draining an agricultural watershed before and after implementation of a state-mandated buffer law passed in 2014 and aimed at protecting water quality. Intensive habitat assessments, electrofishing, and benthic invertebrate sampling were used at the same 13 sites in 2005 and 2018. Average buffer width nearly doubled between surveys, and instream abundance of fine sediments and embeddedness of coarse substrates by fine sediments both declined significantly within 1 to 3 years of buffer establishment. Stream sites also were significantly deeper with faster current velocities, and sites had increased riffle habitat and increased instream vegetative cover for fish after buffer mandates. However, fish and invertebrate biotic integrity scores, and other biotic community metrics, did not display significant improvements after buffer establishment. Stream habitats appear to improve quickly when intact and continuous riparian buffers insulate streams from surrounding agricultural activities, but improvements in biotic communities likely will require more time to adapt to changed habitat conditions.

Impacts of dyke systems on the distribution of benthic invertebrate communities and physicochemical characteristics of surface water in An Giang, Vietnam.

The dyke system plays a vital role in cultivating rice intensively in the Vietnamese Mekong Delta, which protects rice paddy fields from annual floods. This study aimed to examine whether the full-dyke system (FD, which restricts water exchange for a long time) can cause degradation of surface water quality and reduction in benthic invertebrate biodiversity. The surface water quality and benthic invertebrate community were compared between the FD and semi-dyke systems (SD, which permits water exchange during flooding season) using a large number of samples collected seasonally in 2019. The results showed that the surface water quality within the FD system had significantly higher concentrations of TSS, COD, BOD5, N-NO3-, N-TKN, P-PO43-, and TP than compared to the SD system (p < 0.05), indicating greater pollution levels. The benthic invertebrate community was less diverse in the FD system than in the SD system. Only 17 species (belonging to 4 families) were detected in the FD system, and 30 species (belonging to 5 families) were detected in the SD system. The benthic invertebrate community structure changes and biodiversity loss were associated with degraded water quality. The P-PO43- and TP parameters were negatively correlated with the number of species, density, and biomass in the FD system and with the Shannon-Wiener (H') index in the SD system. In conclusion, the FD system has been degrading water quality and causing biodiversity loss.

A marine protected area network does not confer community structure resilience to a marine heatwave across coastal ecosystems.

Marine protected areas (MPAs) have gained attention as a conservation tool for enhancing ecosystem resilience to climate change. However, empirical evidence explicitly linking MPAs to enhanced ecological resilience is limited and mixed. To better understand whether MPAs can buffer climate impacts, we tested the resistance and recovery of marine communities to the 2014-2016 Northeast Pacific heatwave in the largest scientifically designed MPA network in the world off the coast of California, United States. The network consists of 124 MPAs (48 no-take state marine reserves, and 76 partial-take or special regulation conservation areas) implemented at different times, with full implementation completed in 2012. We compared fish, benthic invertebrate, and macroalgal community structure inside and outside of 13 no-take MPAs across rocky intertidal, kelp forest, shallow reef, and deep reef nearshore habitats in California's Central Coast region from 2007 to 2020. We also explored whether MPA features, including age, size, depth, proportion rock, historic fishing pressure, habitat diversity and richness, connectivity, and fish biomass response ratios (proxy for ecological performance), conferred climate resilience for kelp forest and rocky intertidal habitats spanning 28 MPAs across the full network. Ecological communities dramatically shifted due to the marine heatwave across all four nearshore habitats, and MPAs did not facilitate habitat-wide resistance or recovery. Only in protected rocky intertidal habitats did community structure significantly resist marine heatwave impacts. Community shifts were associated with a pronounced decline in the relative proportion of cold water species and an increase in warm water species. MPA features did not explain resistance or recovery to the marine heatwave. Collectively, our findings suggest that MPAs have limited ability to mitigate the impacts of marine heatwaves on community structure. Given that mechanisms of resilience to climate perturbations are complex, there is a clear need to expand assessments of ecosystem-wide consequences resulting from acute climate-driven perturbations, and the potential role of regulatory protection in mitigating community structure changes.

Biomonitoring of radioactive contamination using benthic invertebrate communities in Manzala Lake, Egypt

Manzala Lake, the largest in Egypt’s Nile Delta, has significant human activity. The Lake’s ecological condition has recently been impacted by a significant increase in agricultural, industrial, and urban wastewater discharge. Avaluable tool for monitoring the water quality of Manzal aLake is the sensitivity of invertebrate species to various types of pollution, such as radioactive contamination. Activity concentrations of radionuclides Radium-226 (226Ra),Thorium-232 (232Th), Potassium-40 ( 40K), and Caesium-137(137Cs) were measured in water, sediments and benthic invertebrate samples in 2020. The benthic community’s spatial distribution and the radionuclides’ bioaccumulation were evaluated to determine possible relationships.Thirty taxa of benthic invertebrates were recognised.The data illustrated that the mean activity concentratio nof radionuclides in water was in the order of 40K &gt; 232Th &gt;226Ra &gt; 137Cs, which changed into 40K &gt; 226Ra &gt; 232Th &gt; 137Csin the sediment and benthic invertebrates. Gastropoda and Ostracoda are the dominating groups of benthos in the lake and are related to the highest concentrations of radionuclides. The benthos species with shells dominated at the sites with the highest activity concentration of 226Ra, while soft-bodied organisms dominated in sites with the highest average 137Cs activity in these samples.

Habitat development and species arrival drive succession of the benthic invertebrate community in restored urban streams

BackgroundUrban streams are characterised by species-poor and frequently disturbed communities. The recovery of heavily polluted urban streams is challenging but the simple community structure makes recolonisation patterns more transparent. Therefore, they are generally applicable model systems for recolonisation of restored streams. Principal questions of stream restoration concern the drivers and patterns of recolonisation processes. Rarely, recolonisation of restored streams is recorded for a sufficient time to observe patterns of habitat and community development in detail. Over 10 years, we monitored benthic habitat changes and macroinvertebrate communities of eight restored sites in an urban stream network that was formerly used as an open sewer and thus, almost uninhabitable for macroinvertebrates prior to restoration. We analysed changes in environmental variables and communities with a selection of multi-variate analyses and identified indicator species in successional stages.ResultsProportions of stony substrate and conductivity decreased over time since restoration, while the riparian vegetation cover increased along with the amount of sandy substrate. The communities fluctuated strongly after restoration but began to stabilise after around eight years. TITAN analysis identified 9 species, (e.g. the mayfly Cloeon dipterum and the beetle Agabus didymus), whose abundances decreased with time since restoration, and 19 species with an increasing abundance trend (e.g. several Trichopteran species, which colonised once specific habitats developed). Woody riparian vegetation cover and related variables were identified as major driver for changes in species abundance. In the last phase of the observation period, a dry episode resulted in complete dewatering of some sites. These temporarily dried sections were recolonised much more rapidly compared to the recolonisation following restoration.ConclusionsOur results underline that community changes following urban stream restoration are closely linked to the evolving environmental conditions of restored streams, in particular habitat availability initialised by riparian vegetation. It takes about a decade for the development of a rich and stable community. Even in streams that were almost completely lacking benthic invertebrates before restoration, the establishment of a diverse macroinvertebrate community is possible, underlining the potential for habitat restoration in formerly heavily polluted urban areas.

MACROINVERTEBRATES THE FOOTHILL LAKES OF THE NORTHERN AND NORTHEASTERN ALTAI

The taxonomic composition and abundance of benthic invertebrates in four lakes (Aya, Kireevo, Koksha and Svetloye) of the northern and northeastern Altai were studied in May, July and September 2022. 126 species from 9 classes of invertebrates were identifi ed in the macrozoobenthos of the studied lakes. Lakes Aya and Kireevo are characterized by low species diversity, abundance and biomass of benthic invertebrates. According to the composition and structure of communities of benthic invertebrates, lakes Aya and Kireevo were close to fl atland and low-mountain lakes. High taxonomic diversity and abundance of macroinvertebrates in lakes Koksha and Svetloye were noted. The bottom population of these lakes had features of both fl atland and mountain lakes.

Exploring invertebrate indicators of ecosystem health by focusing on the flow transitional zones in a large, shallow eutrophic lake

The river–lake transitional zone provides a unique environment for the biological community and can reduce pollution inputs in lake ecosystems from their catchments. To explore environmental conditions with high purification potential in Lake Taihu and indicator species, we examined the river-to-lake changes in water and sediment quality and benthic invertebrate communities in the transitional zone of four regions. The spatial variations in the environment and invertebrate community observed in this study followed the previously reported patterns in Taihu; the northern and western regions were characterized by higher nutrient concentrations in water, higher heavy metal concentrations in sediment, and higher total invertebrate density and biomass dominated by pollution-tolerant oligochaetes and chironomids. Although nutrient concentrations were low and transparency was high in the eastern region, the taxon richness was the lowest there, which disagreed with the previous findings and might be due to a poor cover of macrophytes in this study. The river-to-lake change was large in the southern region for water quality and the invertebrate community. Water circulation induced by strong wind-wave actions in the lake sites of the southern region is assumed to have promoted photosynthetic and nutrient uptake activities and favored invertebrates that require well-aerated conditions such as polychaetes and burrowing crustaceans. Invertebrates usually adapted to brackish and saline environments are suggested to be indicators of a well-circulated environment with active biogeochemical processes and a less eutrophic state in Taihu, and wind-wave actions are key to maintaining such a community and natural purifying processes.

Trophic redundancy in benthic fish food webs increases with scarcity of prey items, in the Southern Baltic Sea

Bottom trawling is one of the main pressures on benthic ecosystems, directly impacting the targeted species and physically disturbing the seabed and the benthic invertebrate communities, in turn indirectly impacting benthivorous fish and the entire benthic food web structure and functioning. To predict the cascading effect of bottom trawling on benthic and demersal fish communities, it is crucial to understand the trophic interactions between benthic and demersal fish and benthic invertebrates. Here, we assessed the diet of benthic and demersal fish and the structure and functioning of the benthic food web in two areas in the German Baltic Sea, the Fehmarnbelt and the Odra Bank. The Fehmarnbelt benthic invertebrate community is characterized by a high number of species and biomass, contrary to the one on the Odra Bank which is species poor with high individual abundance but low biomass. We used mixing models based on stable isotopes of carbon and nitrogen combined with stomach content analyses to estimate the fish diet at both sites, and we used community-wide trophic indices, derived from stable isotopes to compare the structure and functioning of the fish benthic food webs. We show that fish in the Fehmarnbelt can chose preferential prey items, resulting in higher trophic diversity, contrary to fish on the Odra Bank, which feed on all available prey species, resulting in higher trophic redundancy. We found that the generalist behavior of fish on the Odra Bank is likely the result of scarcity in prey items, the benthic invertebrate community being species poor with high abundance of small individuals. We demonstrate that the differences in structure and functioning of the benthic fish food web between the two sites was mainly driven by differences in the characteristics of the benthic prey communities.

Experimental warming and browning influence autumnal pelagic and benthic invertebrate biomass and community structure

Abstract Globally, lakes are warming and browning with ongoing climate change. These changes significantly impact a lake's biogeochemical properties and all organisms, including invertebrate consumers. The effects of these changes are essential to understand, especially during critical periods after and before the growing season, that is, autumn and spring, which can determine the composition of the invertebrate consumer community. In this study, we used a large‐scale experimental pond system to test the combined effect of warming (+3°C) and increased input of terrestrial and coloured dissolved organic carbon (gradient of 1.6–8.8 mg/L in the ambient and 1.6–9.3 mg/L in the warm)—which causes browning—on zooplankton and benthic macroinvertebrate biomass and composition during the autumn and the following spring. Total zooplankton biomass decreased with warming and increased with browning, while total zoobenthos did not respond to either treatment. Warming and browning throughout the autumn had no overall interactive effects on zooplankton or zoobenthos. Autumnal warming decreased total pelagic consumer biomass, caused by a decrease in both Rotifera and Copepoda. In contrast, there was no effect on overall benthic consumer biomass, with only Asellus sp. biomass showing a negative response to warming. An autumnal increase in dissolved organic carbon led to increased total pelagic consumer biomass, which was related to increases in Daphnia sp. biomass but did not affect zoobenthos biomass. While we expected zooplankton and zoobenthos biomass to follow responses in primary and bacterial production to treatments, we did not find any relationship between consumer groups and these estimates of resource production. Our results suggest that consumer responses to warming and browning during autumn may lead to less overarching general changes in consumer biomass, and responses are mostly taxon‐specific. This study gives novel insights into the effects of warming and browning on consumer biomass during autumn and spring and increases the understanding of the effects of climate change on invertebrate community biomass in the different habitats.

State of benthic invertebrate communities and water quality in the ponds of Noginsk district of Moscow region

Hydrochemical regime is one of the important factors affecting the species composition and the amount of benthic invertebrate communities in a water body. With heavy metal pollution and high eutrophication, the oligochaete index increases, the species diversity of benthic invertebrate communities decreases, and almost all representatives of the entomofauna disappear, with the exception of chironomids. Pollution with phosphates and ammonium nitrogen has an adverse effect on the development of benthic invertebrate communities. At present, the amount of available scientific data on the influence of hydrochemical factors on the development of benthic invertebrate communities in pond farms seems to be insufficient, the focus is on hydrological factors, and this suggests the relevance of new research in this area. The purpose of this study was to compare hydrochemical and temperature indicators with the quantitative and qualitative composition of benthic invertebrate communities in three ponds of Noginsk district of Moscow region in December 2022 - January 2023. The selection of hydrobiological materials and water samples for hydrochemical analysis was carried out in December 2022 - January 2023 in the ponds of Noginsk district of Moscow region in EPB RRIFF, a branch of the Federal State Budgetary Scientific Institution FRC RIAH named after L.K. Ernst. Pond № 1 has an area of 4,48 ha, pond № 2 has an area of 1,7 ha, pond № 3 has an area of 0,61 ha. The studies conducted in December 2022 - January 2023 showed the presence of correlation between water quality (the sum of hydrochemical indicators: concentration of ammonium and nitrate nitrogen, phosphates, total iron, general and carbonate hardness, total mineralization, as well as water temperature) and benthic invertebrate communities (qualitative and quantitative) development indicators. The best indicators of benthic invertebrate communities development were observed in the pond with the best water quality (from a fishery point of view), the worst ones were observed in the pond with the worst water quality (zoobenthos was not found in samples from this pond). In total, 6 taxones of benthic invertebrate communities were found in the studied ponds.

Long-term trends and drivers of biological invasion in Central European streams

Rates of biological invasion continue to accelerate and threaten the structure and function of ecosystems worldwide. High habitat connectivity, multiple pathways, and inadequate monitoring have rendered aquatic ecosystems vulnerable to species introductions. Past riverine invasion dynamics were largely restricted to large rivers, leaving out smaller rivers that commonly harbour high freshwater biodiversity. Moreover, biodiversity time series have rarely been used to investigate invasions across larger spatial-temporal scales, limiting our understanding of aquatic invasion dynamics. Here, we used 6067 benthic invertebrate samples from streams and small rivers from the EU Water Framework Directive monitoring program collected across Central Europe between 2000 and 2018 to assess temporal changes to benthic invertebrate communities as well as non-native species. We assessed invasion rates according to temperature, precipitation, elevation, latitude, longitude, and stream type. Overall, average daily temperatures significantly increased by 0.02 °C per annum (0.34 °C in total) while annual precipitation significantly decreased by 0.01 mm per annum (−67.8 mm over the study period), paralleled with significant increases in overall species richness (12.3 %) and abundance (14.9 %); water quality was relatively stable. Non-native species richness increased 5-fold and abundance 40-fold, indicating an ongoing community shift from native to non-native species. The observed increase in invasions was stronger in low mountain rivers compared to low mountain streams, with the share of non-native species abundance and richness declining with increasing elevation and latitude but increasing with temperature. We found thermophilic non-native species invasion success was greatest in larger sized streams, at lower latitudes, lower elevations and higher temperatures. These results indicate that widespread environmental characteristics (i.e., temperature) could heighten invasion success and confer refuge effects (i.e., elevation and latitude) in higher sites. High altitude and latitude environments should be prioritised for prevention efforts, while biosecurity and management should be improved in lowland areas subject to greater anthropogenic pressure, where non-native introductions are more likely.

The natural food base of the ponds in Noginsky district of Moscow region

The purpose of this work was to study the natural food base of the ponds in the Noginsk district of the Moscow region in October-November 2022. The selection of hydrobiological materials was carried out in October-November 2022. The pond №1 is a main pond of the EPB of RRIFF, a branch of the FSBSI FRC RIAH named after L.K. Ernst, with an area of 4,48 ha, fertilized with goose and duck droppings. Pond № 2 is ownerless, with peat soil, with an area of about 21,27 hectares. From a fishery point of view, the state of phytoplankton turned out to be more favorable in the ownerless pond. The biomass of phytoplankton in this pond is higher, it is formed mainly by green algae, consumed by both juvenile fish and planktonic organisms, through which the primary production is transferred to the higher levels of trophic pyramid. In the pond № 1, the biomass is much lower and in many respects formed by low-edible blue-green algae. The species diversity of the zooplankton in the EPB RRIFF pond, fertilized with waterfowl droppings, is significantly higher than in the big ownerless pond. The zooplankton biomass here is more than 2 times higher. The number of zooplankton is 1,34 times higher. The percentage of oligochaetes in the benthic invertebrate communities samples from the pond № 1 (68%) indicates moderate water pollution in October-November 2022 with organic matter. Thus, the head pond of the EPB RRIFF, fertilized with waterfowl droppings (the integrated technologies), demonstrated for the benthic invertebrate communities the best indicators of the natural food base state, both in general and in terms of indicators of the individual taxons. The components of the natural food base, which are crucial for the fish nutrition: phytoplankton and benthic invertebrate communities, turned out to be higher in October-November 2022 in the EPB RRIFF pond, fertilized with waterfowl droppings. However, the indicators of phytoplankton were better in the ownerless pond of the Noginsk district of the Moscow region. One of the reasons for the less favorable state of phytoplankton in the EPB RRIFF pond may be the eating of green algae by zooplankton.