Lotic Waters Research Articles

Diversity of Aquatic Beetles (Dytiscidae) along the Altitudinal Gradient and its Relationship with Physico-Chemical Parameters of Water at Tashiding, Tsendagang and Gozhi Gewogs, Dagana, Bhutan

Dytiscidae plays a vital role in the ecosystem; purifies water and serv es as the prey on many organisms. This family of aquatic beetles as predators feeds on small organisms. They are sensitive to environmental changes, it is used as a biodiversity indicator and also a tool for conservation assessment. This study assessed the diversity of Dytiscidae in relation to physico-chemical parameters of water using stratified random sampling at three Geogs in Dagana. Furthermore, the relationship of Dytiscid diversity and taxon richness with the physico-chemical parameters of the lentic and the lotic water bodies along the altitudinal gradient were determined and collected specimens. The total 664 individuals were collected in which five subfamilies of Dytiscidae, 12 genera and 17 species were identified. Pearson’s correlation showed moderately negative correlation between the species diversity and taxon richness based on altitude and pH (p < 0.05). Temperature had moderate positive correlation with species diversity of Dytiscidae. Canonical correspondence analysis (CCA) showed temperature had an effective determining factor for distribution of Dytiscidae. Kruskal Wallis test among different habitats and altitudinal strata showed significant difference in Dytiscids diversity and taxon richness (p < 0.05). The diversity and richness showed a decreasing trend when the altitude increased. The highest diversity was found in marshy area (H = 2.36) and second altitude stratum (800 – 1200 masl) (H = 2.07) in the current study area. Therefore, the best conservation strategy of Dytiscidae could be to protect these areas before they are degraded.

The genus Dorofeyukea (Bacillariophyta, Stauroneidaceae) in karst environments in the Brazilian Pantanal: with the description of four new species

In a Brazilian karst environment, composed predominantly of carbonate rocks, diatoms were collected in periphytic habitat (epiphyton, epilithon, epipsammon) in lentic and lotic water bodies from the Serra da Bodoquena. This Pantanal region is known for its tourist and scenic value, covering springs and rivers with extensive formation of active limestone tufa. Six species of <i>Dorofeyukea </i>were investigated under light and electron microscopy. The genus is characterized by a narrow stauroid fascia surrounded by some irregularly shortened striae, uniseriate slightly radiated striae, areolae circular or rectangular covered internally by a hymenes and apical pseudosepta. Four new species are described and compared with similar taxa <i>Dorofeyukea bahlsii </i>sp. nov., <i>D. bodoquenensis sp. nov.</i>, <i>D. calcarea sp. nov.</i>, and <i>D. pantanalensis </i>sp. nov. The new species are distinguished from each other and from similar taxa of <i>Dorofeyukea</i> mainly by the valve contour and shape of the apices. <i>Dorofeyukea kotschyi</i> (Grunow) Kulikovskiy, Kociolek, Tusset et T. Ludwig and <i>D. texana </i>(Patrick) Kulikovskiy et Kociolek were also recorded, described and illustrated in this study.

Ichthyofaunal diversity of Jammu region of North-Western Himalaya and its conservation status

Jammu and Kashmir has enormous fisheries potential due to its vast area and quantity of freshwater sources. The UT has rivers like Chenab, Tawi, Ravi, and Jhelum, as well as lakes including Dal lake, Wular lake, Manasbal lake, and Surinsar, Manasar lake. The purpose of this study is to summarize some of the key studies done on the Ichthyofaunal diversity of numerous water bodies in the Jammu region, as well as to create an inventory of the region’s Ichthyofauna while analyzing the dominant and least prominent species. The examination undertaken revealed the presence of 158 distinct fish species belonging to 10 orders, with Cypriniformes being the most dominating order and Cyprinidae being the most significant contributing family, while Anabantiformes and Clupeiformes were in traces. Furthermore, analysis of conservation status of the fauna revealed that, majority of the species in the region have a conservation status of “Least Concern”, while a few species are endangered or vulnerable. Analysis of fish fauna of the region’s major lotic water bodies finds that river Ravi has the largest fish diversity; however, a comparative analysis of fish fauna reveals that diversity is diminishing in the region necessitating extensive conservation strategies.

Diversity of the Anisoptera & Zygoptera (Odonata: Insecta) of Swat, Pakistan.

Odonates are important biological control agents for the control of insect pests and insect disease vectors of medical and veterinary importance. The present study was conducted to evaluate the odonate fauna of Swat, Pakistan from March to October 2019. A total of 200 specimens of odonates were collected from diverse habitats. The collected specimens of the order Odonata belonged to 5 families, three families of suborder Anisoptera namely Libellulidae, Gomphidae and Aeshnidae while two families of suborder Zygoptera (Chlorocyphidae and Coenagrionidae). The specimens were categorized into 12 genera and 22 species. Libellulidae was the dominant family (n = 138) accounting for 69% of the odonate fauna. Orthetrum was the dominant genus (n = 73) of suborder Anisoptera accounting for 36.5% of the odonate fauna. The least dominant genera were Anax, Paragomphus and Rhyothemis (n = 5 each) accounting each for 2.5% of the odonate fauna. In Zygoptera, the dominant genus was Ceriagrion (12.5%) and the least dominant genus was Ischnura (6%). Pantala flavescens (Fabricius, 1798) was the most abundant odonate species in the study area recorded from all surveyed habitats. Shannon Diversity Index (H) was 2.988 and Simpson Diversity Index (D) was 0.95 for the collected odonate fauna. The highest abundance of Odonata was recorded in August, September and May while no odonate species were recorded in January, February, November and December. Lotic water bodies were the most suitable habitats with abundant odonate fauna. Anax immaculifrons (Rambur, 1842) was the largest sized odonate species having a wingspan of 53.2±1.63 mm and body length of 56.3 ± 0.4 mm. The present study shows the status of odonate fauna of Swat, Pakistan in diverse habitats and seasonsonal variation throughout the year. Further work is recommended to bridge the gaps in the existing literature.

Influence of mattresses washing on the water quality and phytoplankton diversity in selected industrial outlets of Tamil Nadu

The impact of anthropogenic activity of mattresses washing on the quality of two lotic water bodies of Cuddalore SIPCOT industries outlet water bodies two different stations were analysed. The industrial waste water currents battered along the Freshwater ecosystem near SIPCOT industries. Hence an attempt was made to record outlet water bodies two different stations were analysed. The water samples were collected during summer (April-June, 2021) and winter seasons (Oct-Dec 2021) and analysed for various physicochemical parameters. Decrease in dissolved oxygen concentrations along with tremendous increase in electrical conductivity in both the water bodies, was observed due to mattresses washing by using detergents. Heavy metals like lead, cadmium and nickel were absent throughout. The values of iron was increased while manganese was traced out after this activity. This proved that water quality was found to be hampered in both the stations. A total of 65 species of phytoplankton belonging to different taxonimic groups were identified. Among these, 25 species belong to Bacillariophyceae, 20 species to Chlorophyceae, 15 species to Cyanophyceae and 5 species to Euglenophyceae. The numerical superiority of phytoplankton reveals that Nitzschia sps. (6.66 x 103 units/1) is dominant in SIPCOT industries water outlet. The maximum value of Simpson index (SR) or species richness (0.55) was recorded in Cuddalore SIPCOT industry. The high value of species evenness index (J) was also recorded (0.69) in Cuddalore SIPCOT industry. The maximum value of Shannon’s overall index (H¢) of species diversity (1.38) was recorded in industrial outlet. Microcystis aeruginosa, Anabaena, Oscillatoria, Merismopedia, Aphanizomenon, Chlorella, Cosmarium, Scenedesmus, Closteridium, Navicula and Nitzschia were observed in two stations. These are pollution indicator species used for monitoring the environment.

Status and Scope of Conventional Morphometry and its Integration with Bar Coding in Jammu and Kashmir (J&amp;K) Fisheries.

Correct identification is at the core of taxonomy. Although morphometric characterization is the most straightforward and cost-effective method, it has a number of limitations. By overcoming this limitation, bar coding of mitochondrial cytochrome c oxidase gene (COI) helps in accurate and cost-effective identification of fish species. This communication discusses limitations of conventional morphometry and how its integration with bar coding can help to solve the taxonomic ambiguity of morphologically similar species. Along with that information, different water bodies from J&amp;K region have been analysed with special reference to fish diversity which revealed that the diversity is more in Jammu region as compared to Kashmir, due to favourable climatic conditions and larger number of lotic water bodies and also the fact that the integrated approach has been successfully adopted in Kashmir valley,contributing to accurate identification of fish fauna. There is a lot of room for research in this area as bar coding of fishes has just become popular in the Jammu region, despite its immaturity. This will aid in a better knowledge of the region's fish ecology, the preservation of the gene pool, and the rise of economically significant species.

The deflectors influence on flow complexity, bed morphology, sediment transport and water quality of urban lotic waters ‐ A laboratory study

AbstractIn this laboratory study different combinations of bed (sand, pebble gravel [gravel], and a mix of sand and gravel) and flow (typical and overtopping) were experimented with to investigate the impact of porous deflectors in flow diversity, water quality, and fish performance in prismatic open channels. Deflectors changed the gradually varied flow to a rapidly varied flow, as a sudden change in the water depth was observed at the deflectors, and this change was large for smooth beds. With the presence of gravel, the scouring near the downstream deflector was almost twice that of the sand bed, and with the scouring at its own upstream deflector, irrespective of whether the flow was typical or overtopping. This behavior was a result of sand mobilization due to shear stress and sand mobilization aided gravel transport. The mixed bed showed less gravel movement compared to the gravel‐only bed. The percentage of sediment washed out was minor for all bed scenarios, indicating that sediment transport was local. Relative to the sand bed without deflectors (representing a typical urban canal), deflectors resulted in reduced and improved water quality (in terms of sediment load) for sand, and mixed bed, respectively. The fishes found refuge and were comfortable in the pool areas created by deflectors unlike in channels without deflectors where they showed exhaustion.

Linking the Community and Metacommunity Perspectives: Biotic Relationships Are Key in Benthic Diatom Ecology

The ecology of benthic diatoms is scarce in diatom reviews, and it seems that the loss of interest in their local ecology (populations–communities) coincides with an increase in metacommunity studies. We include a review of the latter to highlight some unresolved issues. We aim to demonstrate the relevance of local population–community ecology for a better understanding of the metacommunity by addressing gaps such as the relevance of biotic relationships. We analyzed 132 assemblages of benthic diatoms from two neighboring catchments, with varying altitudes, lentic and lotic waters and substrates. Population–community features (e.g., populations’ relative abundance and alpha diversity) and metacommunity descriptors (e.g., beta diversity indices) were related to likely control factors such as space, catchment features, local physico-chemistry and biotic environment. Our results confirm the relevant role of local interactions between diatoms and with the biotic environment as the mechanism in assembly communities. Moreover, abiotic habitat stability enhances alternative assemblages, which are the base of the metacommunity structure, mostly by taxa sorting and mass effects. Our results suggest that in order to better disclose factors controlling metacommunities, we must study their communities at local scales where mechanisms that explain their assemblage occur, as this is the bridge to a better understanding of benthic diatom ecology.

A synthesis of floodplain aquatic ecosystem metabolism and carbon flux using causal criteria analysis

AbstractThe transformation of solar energy into organic matter by autotrophs (gross primary production [GPP]) and the use of that energy by autotrophs and heterotrophs (ecosystem respiration [ER]) describe the total energy available to support food webs. Rates of GPP and ER vary with temperature, light, hydrology, nutrients, and organic matter supply and quality yet despite their obvious importance, spatiotemporal variation of metabolic patterns among floodplain habitats, and their relationship to inundation dynamics remain unclear. We set out to review the peer‐reviewed literature surrounding the influence of the magnitude, frequency, and duration of floodplain inundation on aquatic ecosystem metabolism and carbon flux by rigorously testing a suite of cause–effect hypotheses using a causal criteria analysis. Causal criteria analysis is a literature synthesis approach developed to address a lack of experimental data and subsequent weak inference of causal relationships. We found support for 3 of the 14 hypotheses we tested relating to putative causal relationships: (1) large floods transfer more carbon from floodplains to the river channel than small floods via the increase in inundation area leading to more overall leaching of floodplain litter, (2) in high turbidity floodplain habitats rates of GPP are reduced by restrictions to photic depth, and (3) a positive correlation between nutrients and GPP—generally GPP in floodplain wetlands increases with nutrient levels. We obtained inconsistent evidence for a causal relationship between macrophytes and aquatic GPP, with studies reporting both a negative influence from decreased light caused by macrophyte shading and a positive influence from structural support provided by macrophytes for periphyton growth. For the remaining 10 hypotheses, there was insufficient evidence to support causal relationships, including for any hypotheses relating to frequency or duration of floodplain inundation. Our results emphasize that despite an apparent wealth of metabolic studies in riverine ecosystems, floodplain metabolic dynamics remain poorly studied, likely due to less investment and increased difficulty compared to lotic waters. The review also highlighted aspects of floodplain aquatic ecosystem metabolism for which there are significant knowledge gaps in the literature, in particular metabolic responses to inundation frequency and duration. Our results call attention to the importance of site specificity and temporal changes when predicting putative cause–effect relationships between floodplain inundation and metabolic patterns.

The drawdown phase of dam decommissioning is a hot moment of gaseous carbon emissions from a temperate reservoir

ABSTRACT Dam decommissioning (DD) is a viable management option for thousands of ageing dams. Reservoirs are large carbon sinks, and reservoir drawdown results in important carbon dioxide (CO2) and methane (CH4) emissions. We studied the effects of DD on CO2 and CH4 fluxes from impounded water, exposed sediment, and lotic water before, during, and 3–10 months after drawdown of the Enobieta Reservoir, north Iberian Peninsula. During the study period, impounded water covered 0–100%, exposed sediment 0–96%, and lotic water 0–4% of the total reservoir area (0.14 km2). Areal CO2 fluxes in exposed sediment (mean [SE]: 295.65 [74.90] mmol m−2 d−1) and lotic water (188.11 [86.09] mmol m−2 d−1) decreased over time but remained higher than in impounded water (−36.65 [83.40] mmol m−2 d−1). Areal CH4 fluxes did not change over time and were noteworthy only in impounded water (1.82 [1.11] mmol m−2 d−1). Total ecosystem carbon (CO2 + CH4) fluxes (kg CO2-eq d−1) were higher during and after than before reservoir drawdown because of higher CO2 fluxes from exposed sediment. The reservoir was a net sink of carbon before reservoir drawdown and became an important emitter of carbon during the first 10 months after reservoir drawdown. Future studies should examine mid- and long-term effects of DD on carbon fluxes, identify the drivers of areal CO2 fluxes from exposed sediment, and incorporate DD in the carbon footprint of reservoirs.

CO2 dynamics in a small and old subtropical reservoir in East Asia: Environmental controls driving seasonal and spatial variability

Inland waters have been increasingly viewed as hotspots for greenhouse gas (GHG) emissions owing to their strong capability to intercept and mineralize carbon from the terrestrial environment. Although small waterbodies in humid subtropical climates have the potential to emit considerable amounts of GHG, their emission patterns have remained understudied. This study involved intensive measurements of carbon dioxide (CO2) emissions from a small reservoir and its upstream and downstream reaches located in subtropical Hong Kong. Our results revealed that a variety of metabolic, hydrological, and hydrochemical processes play a critical role in regulating its CO2 dynamics. The reservoir was an overall source of CO2 to the atmosphere with an average areal flux of 24.6 mmol m−2 d−1, and it occasionally functioned as a sink for atmospheric CO2 under intense solar radiation when primary productivity was high. This flux is on the low side relative to that of global (sub)tropical reservoirs, which was likely attributable to the prolonged history of the reservoir (>150 years) and the occasional undersaturation of CO2 in the water column. We also noticed pronounced differences in the underlying controls of CO2 dynamics between the reservoir and its upstream and downstream reaches, emphasizing the importance of taking into account the distinct characteristics of both lentic and lotic waters when evaluating catchment-scale CO2 fluxes.

Electrofishing distances for sampling fish assemblages in oxbow lakes of the River Rhine

Assessment of fish assemblage structure depends on representative sampling. In contrast to lotic water bodies, recommendations for a general study design are sparse for lentic water bodies. Therefore, we evaluated the fish assemblages in different littoral structure types (e.g. macrophytes and riprap stone) and the impact of these structure types on the minimum distance required to obtain samples representative of fish species number in oxbow lakes. Boat-based electrofishing was used at 88 sections, each 200-m long within five oxbow lakes connected to the Upper River Rhine in southwest Germany. Submerged macrophytes and riprap stones were important littoral structures for determining fish community structure. Littoral structure was related to species accumulation, which illustrates the importance of littoral structure to define the minimum length of sampling. Our findings suggest that at least 200-m stretches should be sampled to describe fish assemblages in oxbow lakes.

The role of phytoplankton communities on coupled carbon-silicon cycling in a large floodplain lake system

Carbon (C) and silicon (Si) are essential lake ecosystem components, impacting both phytoplankton growth and other available elements and nutrients. In this study, we selected a typical floodplain-lake system to explore the seasonal role of coupled C and Si as matter is imported and exported through lotic water processes. Results showed considerably higher dissolved inorganic carbon (DIC), dissolved organic carbon (DOC), and dissolved total carbon (DTC) concentrations during the transitional stage between the dry and wet season (here referred to as TDW) compared to the other seasonal stages (5.81 mg/L–28.80 mg/L), indicating that imported runoff significantly effects the transport of C and Si. Rock weathering was the main source of dissolved silicon (DSi). The dilution effect and water temperature may also impact DIC, DOC, and DTC concentrations. Except for the wet season, Bacillariophyta was the dominant phytoplankton taxon, and diatom growth as well as the growth of other algae taxon may influence DSi and DTC concentrations through several biochemical processes. This study describes effects of coupled C and Si and highlights variation in environmental variables driven by the resident phytoplankton communities in a lake ecosystem.

MULTIVARIATE ANALYSIS SHOWING IMPACT OF DIFFERENT ENVIRONMENTAL FACTORS ON SPECIES RICHNESS AND SPECIES DENSITY OF FRESHWATER MOLLUSC COMMUNITIES INHABITING WATERS OF NORTH-WEST HIMALAYAS

Freshwater molluscs face extreme threat due to anthropogenic stress which is reflected in their changing population structure over time. The extent of this phenomenon needs to be monitored and proper management of freshwater ecosystem should be done. In the present communication, an approach was undertaken to study the effect of ten different physical and chemical factors affecting mollusc density and mollusc richness in both lentic and lotic water bodies of North-West Himalayas. A total of 10 species of gastropods and 3 species of bivalves were recorded. Bivalves remained absent from both lentic bodies while gastropods dominated in both lotic waters in terms of taxa richness. On subjecting physical and chemical parameters to a multivariate analysis, 7 out of 10 factors were found significant after univariate Analysis of Variance (p&lt;0.05). Principal component analysis showed that all the study stations varied in terms of physical and chemical conditions in different seasons. Canonical correspondence analysis revealed that dissolved oxygen, depth, alkalinity, Calcium ions and Chloride ions were the variables that significantly associated with the distribution of molluscs. The regression analysis revealed that the concentration of chloride ions was the common factor that was negatively related to both taxa richness and taxa density.

Potential microbial enzyme activity in seasonal snowpack is high and reveals P limitation

AbstractMicrobes in snow and ice ecosystems in polar regions contribute substantially to C, N, and P cycling, but few studies have explored microbial activity in seasonal snow. The purpose of this study was to explore the relative importance of snow microbial processing of C, N, and P compounds in atmospheric deposition and litter and detect elemental limitations of snow microbes in Rocky Mountain conifer forests. Enzyme activity in snow was orders of magnitude greater than activity reported for lentic and lotic waters in similar environments. Proportions of C/P‐ and C/N‐acquiring enzymes suggest that snow samples were P limited, or C and P co‐limited, while lentic and lotic waters were more N limited. As such, microbes in seasonal snow may change the composition of nutrients and carbon, but these processes are vulnerable to changes in atmospheric deposition and snow extent and duration, which could affect nutrient processing across large areas.

Evaluation of the contraction and expansion of lentic water systems under the influence of the ENSO phenomenon (case study. Department of Córdoba, Colombia)

The sustainability of ecosystems and economic activities depend significantly on the availability of water, which can be affected by its temporal variability. Colombia is one of the countries that suffers high temporal variability of the water resource because of global, regional, and local phenomena. One of the macro-climatic events that alter the water regime is ENSO. Its impact on lotic water bodies is well known, while the effects on lentic systems are unknown. In this study, a methodology, which integrates climatic analyses with remote sensing studies, was designed to evaluate the relationship between the expansion and contraction of lotic bodies under the ENSO event, verified in four welt lands (ciénagas) in the department of Córdoba. The results showed that the dynamics depend up to 60 % on this macro-climatic event. The methodology developed can be considered as a tool for environmental planning of the territory around the lagoon systems, since it allows estimating buffer zones.

Hydrobiological Study of Lotic Water of Yamuna River at Yamuna Nagar, Haryana, India during 2018-2019

The current study deals with hydrobiological examination of lotic water of Yamuna river at Yamuna Nagar, Haryana, India to assess the oscillation in the physico-chemical parameters. The monitoring of water quality parameters was performed consecutively during; July, 2018 to June, 2019. The month wise onsite thermal examination, and titrimetric/ volumetric estimation of collected water samples showed seasonality biased pattern throughout the investigation. The mean value of water temperature (oC), dissolved oxygen (mg/l), pH, hardness (mg/l), alkalinity (mg/l) and acidity (mg/l) ranged between 11.9–29.5 oC, 3.4–7.0 mg/l, 6.3– 7.6, 111.25–170.75 mg/l, 64.06–122.0 mg/l and 12.57–25.29 mg/l respectively. The monthly possible source of factors responsible for the spatial fluctuations in the hydrobiological parameters of riverine water was assessed through the advanced numerical tools. The observation reflected the requirement of urgent and systematic management strategies to overcome these invisible scarce and conserve the natural quality of incredible water resources.

Developmental Stages of Lotic-breeding Toad, Bufo torrenticola, with a Comparison to Lentic-breeding B. japonicus formosus (Amphibia: Anura: Bufonidae)

The development of lotic-breeding Bufo torrenticola is described from zygote to completion of metamorphosis in captivity at 13±1°C. We delimit 56 developmental stages based on external features. We describe developmental stages so as to be comparable to common stages that are widely used for anurans. We also compare the larval development between B. torrenticola in lotic water and lentic water, and with lentic-breeding B. japonicus formosus in lentic water. Our results suggest tadpole mouth size in B. torrenticola is determined by genetic factors, but the tail muscle volume is determined by both genetic and environmental factors.

The Evaluation of Bacterial Abundance and Functional Potentials in the Three Major Watersheds, Located in the Hot Spring Zone of the Tatun Volcano Group Basin, Taiwan.

The Tatun Volcanic Group (TVG), located in northern Taiwan, is characterized by acidic hot springs where the outflow of the hot springs may affect the properties of the associated lotic water bodies. We investigated the bacterial diversity and functional profiles of the Peihuang (PHC), HuangGang (HGC), and Nanhuang Creeks (NHC) located in the TVG basin using 16S rRNA gene sequencing coupled with statistical analyses. Water samples were collected from various streams of the creeks for two months of the year. The NHC showed the highest diversity, richness, and a unique number of phyla, which was followed by the HGC. A reduced number of phyla and a lower diversity was noticed in the PHC. The NHC was found to be abundant in the genera Armatimonas, Prosthecobacter, Pirellula, and Bdellovibrio, whereas the HGC was rich in Thiomonas, Acidiphilium, Prevotella, Acidocella, Acidithiobacillus, and Metallibacterium. The PHC was abundant in Thiomonsa, Legionella, Acidocella, and Sulfuriferula. The samples did not show any strong seasonal variations with the bacterial diversity and abundance; however, the relative abundance of each sampling site varied within the sampling months. The iron transport protein- and the sulfur metabolism-related pathways were predicted to be the key functions in all the creeks, whereas the heavy metal-related functions, such as the cobalt/nickel transport protein and the cobalt–zinc–cadmium efflux system were found to be abundant in the HGC and PHC, respectively. The abundance of Bdellovibrio in the NHC, Diplorickettsia in the HGC, and Legionella in the PHC samples indicated a higher anthropogenic impact over the creek water quality. This study provides the data to understand the distinct bacterial community structure, as well as the functional potentials of the three major watersheds, and helps the knowledge of the impact of the physicochemical properties of the TVG hot springs upon the watersheds.

Environmental DNA captures native and non-native fish community variations across the lentic and lotic systems of a megacity.

Globally, urbanization poses a major threat to terrestrial biodiversity, yet its impact on fish diversity is poorly understood, mainly because of surveying difficulties. In this study, environmental DNA metabarcoding was used to survey fish communities at 109 lentic and lotic sites across Beijing, and how environmental variables affect fish biodiversity at fine urban spatial scales was investigated. We identified 52 native and 23 non-native taxa, with lentic and lotic waters harboring both common and habitat-specific species. Water quality strongly affected native fish diversity, especially in lentic systems, but had little influence on non-native diversity. Fish diversity showed little response to urban land cover variation, but the relative sequence abundance of non-natives in lotic waters increased linearly with distance from the city center. Our findings illustrate the complex effects of urbanization on native versus non-native fishes in different aquatic habitats and highlight the distinctive considerations needed to conserve urban aquatic biodiversity.