Nutrient additions to wetlands in the Interlake region of Manitoba,Canada: effects of periodic additions throughout the growing season

The Interlake region of central Manitoba is characterized by numerous shallow, relatively unproductive wetlands. Typically, these wetlands are poorly utilized by breeding waterfowl in spite of generally reliable water conditions during spring and summer. Nutrient additions were made throughout the growing season to 18 PVC enclosures installed in a low productivity wetland near Lundar, Manitoba. Inorganic phosphorus (as H₃PO₄) and nitrogen (as NH₄NO₃) were added at bi-weekly intervals during the summer of 1988 at target rates of 0 and 0, 30 and 800, and 60 and 1600 µg 1^–1 (P and N respectively). Algal and invertebrate communities were monitored from mid-June to September, 1988. Phytoplankton, epiphytic periphyton and metaphyton communities demonstrated significant increases in biomass over the treatment period. No significant differences in epipelon community biomass were noted. An examination of several indicators of nutrient deficiency indicated that algal productivity was moderately to severely limited in all enclosures, with little or no mitigative effects noted due to nutrient addition treatment. No significant differences in numbers or biomass of total invertebrates or invertebrate functional groups attributed to fertilization were observed. Nutrient additions did increase community productivity, however the levels used in this study were insufficient to yield a sustained increase in primary or secondary productivity.     

Monitoring wetlands in a salinizing landscape: case studies from the Wheatbelt region of Western Australia

Three elements of wetland biodiversity (aquatic invertebrates, waterbirds and overstorey vegetation of the wetland edge) have been monitored since 1998 at Lake Eganu and Paperbark Swamp in the Western Australian Wheatbelt to provide information about the changes occurring in wetland biodiversity in a landscape that is severely affected by dryland salinization. Changes in extent of wetland vegetation since the 1960s were examined using historical aerial photographs and waterbird use of Lake Eganu during the early 1980s was compared with recent waterbird survey results. Lake Eganu, which is within a major drainage line, started to become salinized in the mid-1960s, about 70 years after land clearing began in the catchment, and its salinity has increased an order of magnitude. The extent of wetland overstorey vegetation and the richness of freshwater aquatic invertebrates have both declined about 80%. Waterbird richness has also declined over the past 20 years, with changes in species composition. Salinization has not occurred at Paperbark Swamp, which is in a small catchment off the main drainage line, and there has been no consistent change in the biodiversity elements monitored.     

Diseases and parasites in wolves of the Riding Mountain National Park region, Manitoba, Canada

We examined wolf (Canis lupus) blood and fecal samples from the Riding Mountain National Park (RMNP) region of Manitoba, Canada. In 601 fecal samples collected during two study periods in RMNP and the Duck Mountain Provincial Park and Forest (DMPPF) we found gastrointestinal helminth eggs from Alaria sp. (15.5%), Capillaria sp. (1.0%), taeniid tapeworms (30.8%), Toxascaris sp. (1.7%), Toxocara sp. (0.2%), Trichuris sp. (2.2%), and Moniezia sp. (0.5%). In addition, we found Demodex sp. (0.2%) and the protozoal cysts/oocysts of Sarcocystis sp. (37.3%), Cryptosporidium sp. (1.2%), coccidia (Isospora sp. or Eimeria sp.) (1.7%), and Giardia sp. (29.5%). No fecal shedding of canine parvovirus (CPV, n=387) was detected. All 18 blood samples collected in RMNP showed CPV exposure and eight of 18 blood samples indicated canine distemper virus (CDV) exposure. One wolf died from CDV. Our results are consistent with previous findings on pathogens affecting wolves and with high Giardia sp. prevalence in wolves inhabiting agricultural regions.     

Nutrient additions in pristine Patagonian Sphagnum bog vegetation: can phosphorus addition alleviate (the effects of) increased nitrogen loads

Sphagnum-bog ecosystems have a limited capability to retain carbon and nutrients when subjected to increased nitrogen (N) deposition. Although it has been proposed that phosphorus (P) can dilute negative effects of nitrogen by increasing biomass production of Sphagnum mosses, it is still unclear whether P-addition can alleviate physiological N-stress in Sphagnum plants. A 3-year fertilisation experiment was conducted in lawns of a pristine Sphagnum magellanicum bog in Patagonia, where competing vascular plants were practically absent. Background wet deposition of nitrogen was low (≈ 0.1-0.2 g · N · m(-2) · year(-1)). Nitrogen (4 g · N · m(-2) · year(-1)) and phosphorus (1 g · P · m(-2) · year(-1)) were applied, separately and in combination, six times during the growing season. P-addition substantially increased biomass production of Sphagnum. Nitrogen and phosphorus changed the morphology of Sphagnum mosses by enhancing height increment, but lowering moss stem density. In contrast to expectations, phosphorus failed to alleviate physiological stress imposed by excess nitrogen (e.g. amino acid accumulation, N-saturation and decline in photosynthetic rates). We conclude that despite improving growth conditions by P-addition, Sphagnum-bog ecosystems remain highly susceptible to nitrogen additions. Increased susceptibility to desiccation by nutrients may even worsen the negative effects of excess nitrogen especially in windy climates like in Patagonia.     

Ecological responses to nutrients in streams and rivers of the Colorado mountains and foothills

1. Abundance and composition of periphyton and benthic macroinvertebrates were treated as potential nutrient response variables for 74 streams in montane Colorado. The streams ranged from unenriched to mildly enriched with nutrients (N, P). 2. The study showed no meaningful relationship between periphyton biomass accumulation and concentrations of total or dissolved forms of nitrogen or phosphorus. Nutrient concentrations were also unrelated to periphyton and macroinvertebrate richness, diversity and community composition. Macroinvertebrate communities did, however, show a strong positive relationship to periphyton abundance. 3. A positive response of periphyton biomass to increasing nutrient concentrations has been well documented over large ranges of nutrient concentrations. Our study suggests that the nutrient response is suppressed by other controlling factors on the lower limb of the nutrient response curve (i.e. at low nutrient concentrations); a quantitatively significant response occurs only in excess of a threshold beyond which nutrients become dominant over other controlling factors. This interpretation of the results is consistent with published meta‐analyses showing lack of nutrient response for a high proportion of experimentally enriched periphyton communities, and division of responses between N and P for communities that do show growth in response to enrichment. 4. Grazing probably is not the key controlling variable for periphyton in Colorado mountain streams, given that the highest chlorophyll concentrations are associated with the highest abundances of macroinvertebrates. Modelling indicates that the initial amount of periphyton biomass at the start of the growing season, in conjunction with elevation‐related length of the growing season and water temperature, explains most of the variation in periphyton accumulation among these streams, but there is a yet unexplained suppression of periphyton growth rates across all elevations.     

Nutrient uptake and growth kinetics in brown seaweeds: Response to continuous and single additions of ammonium

The brown seaweeds Fucus distichus Linnaeus subsp. edentatus (de la Pylaie) Powell, a perennial, and Chordaria flagelliformis (O.F. Mueller) C. Agardh, a summer annual, were grown in continuous-flow greenhouse cultures. In winter, the growth of Fucus distichus ( μ = 0.01 · day^?1 ) in culture was not stimulated by added ammonium. Nitrogen in excess of the growth requirement was accumulated in the thallus ( 1.34–2.18 % N by dry wt, depending on the N-loading). In summer, the growth of both species in continuous cultures was stimulated by added ammonium. Chordaria flagelliformis showed higher rates of both growth (μ_max = 0.109 · day^?1) and ammonium uptake $\text{(V}{}_{\max }\text{= 23.2 μmol NH}{}_4{}^{\mathrm{+}}\text{· h}{}^{\mathrm{?1}}\text{· g dry wt}{}^{\mathrm{?1}}\text{)}$ than Fucus distichus (μ_max = 0.074 · day^?1, V_max = 13.9 μmolNH₄⁺ · h^?1 · gdrywt^?1). Calculated nitrogen subsistence quotas were similar in the two species (0.7% N in Chordaria, 0.6% N in Fucus). In those continuous cultures which did not receive added ammonium, Chordaria stored less nitrogen in excess of the subsistence quota than Fucus, although both species accumulated nitrogen at increased N-loading. Transient uptake rates were measured in response to single additions of ammonium. At any given initial concentration, short-term (30 min) uptake rates were a decreasing function of the thallus nitrogen quota and were higher for Chordaria than for Fucus. In N-depleted plants, short-term ammonium uptake rates exceeded both the uptake rates predicted from continuous cultures and the nitrogen requirements for growth. Chordaria flagelliformis, in particular, is able to scavenge efficiently low ambient N-nutrient concentrations and to sequester rapidly transient ammonium pulses. In comparison with Fucus distichus, Chordaria flagelliformis appears to be better adapted to short-term fluctuations in nutrient availability (on a scale of minutes to hours). Their N-storage capability allows both of these seaweeds to buffer the effect of fluctuations in external N-nutrient concentrations on their growth rates over periods of days to several weeks.     

Flame Chlorosis: a New, Soil-transmitted, Virus-like Disease of Barley in Manitoba, Canada

Abstract "Flame Chlorosis" of barley was first observed in two fields of spring barley near Newdale, Manitoba, Canada in late June, 1985. Disease symptoms included leaf chlorosis in a "flame" -like pattern, severe stunting, and failure to produce fertile heads. Afflicted plants were found in circular patches in two adjoining fields, and scattered diseased plants were identified in several nearby fields. Surveys in 1986 and 1987 identified scattered diseased plants in a small number of barley fields, most within 50 km of the original Newdale site. In 1988, the disease was identified at many more locations near Newdale, and at two neighbouring sites the disease occurred at levels sufficient to cause economic loss. In addition, flame chlorosis was identified at several locations outside the Newdale region.
To date the flame clorosis agent has been transmitted only by planting seed or seedlings in soil where plants with symptoms of flame chlorosis had grown earlier. After transfer to sterile potting medium, afflicted plants continued to produce leaves with symptoms. The cytopathology of flame chlorosis differed from that of the known soil-borne viruses of cereals. No inclusions of particles were observed, and instead of the characteristic pinwheel-inclusions, there was massive vesiculation and peripheral distortion of chloroplasts and mitochondria. A set of double-stranded (ds) RNAs, ranging in size from about 900 to 2800 base-pairs (bp) and distinct from any described for a known cereal virus, was isolated from plants afflicted with flame chlorosis, while no dsRNA was isolated from healthy tissue of the same cultivar.     

Differences exist in bird communities using restored and natural wetlands in the Parkland region,Alberta, Canada

Wetland restoration is used to compensate for historic and ongoing wetland losses. We compared bird community composition in 24 restored wetlands and 36 natural wetlands in the Parkland region of Alberta. Natural wetlands ranged in exposure to agricultural activity and were binned into three classes (low, medium, and high disturbance). Although the abundance and average species richness of birds were similar between restored and natural wetlands (analysis of variance: p > 0.22), the avian community composition differed significantly among wetland types (multiresponse permutation procedure [MRPP]: A = 0.05, p < 0.001). The avifauna using restored wetlands was distinct from the avifauna using natural wetlands spanning a range of disturbance levels (A = 0.02–0.06; p ≤ 0.006). Notably, restored wetlands were surrounded by less shrub/forest cover and more open water than low‐disturbance, natural wetlands. The majority (58%) of species using the surveyed wetlands were not classified as wetland‐dependent. Interestingly, if only wetland‐dependent species are considered, the avifauna using restored wetlands is no longer distinctive (MRPP: A < 0.01, p = 0.187), although the abundance of wetland‐dependent birds was marginally higher in restored wetlands (n = 24) than in low‐disturbance, natural wetlands (n = 10; Tukey's honestly significant difference test: p = 0.041). Overall, restored wetlands had reduced beta diversity compared to natural wetlands, regardless of whether the avifauna were restricted to wetland‐dependent species or considered comprehensively. This draws into question the legitimacy of the assumption that restoration can fully offset continued losses of natural wetlands.     

Effects of hot ground water on a small swamp-stream in Nova Scotia,Canada

We examined the effects of hot spring water (35–45 °C) on the ecology of a small, intermittant swamp-stream in Nova Scotia, Canada. Temperatures diminished quickly with distance downstream from the hot spring because of abundant inflow of cold ground water (<10 °C), but elevated temperature effects were detectable 130 m downstream. The brook below the hot spring supported a dense mat of the cyanobacterium Oscillatoria (10 m) followed by the green alga Vaucheria taylorii (40 m). Herbaceous vegetation below the algal zones was also altered by the hot water inflow, even where the temperature increase was slight. The structure of the sparse community of benthic invertebrates was sharply different at sites of different stream temperature: only oligochaete worms, ostracods, chironomids, and a single species of snail thrived at the warmest sites; cold downstream sites supported a typical headwater stream community. Mass loss from decomposing leaves of speckled alder was fast at all sites and strongly correlated with water temperature. The changes in community composition and decomposition rate in response to added heat persisted even where the temperature increase was small, indicating a tight coupling of ecosystem structure and function with the physical environment.     

Species composition,abundance and emergence phenology of midges (Deiptera: Chironomidae) in a brown-water stream of West-Central Alberta,Canada

Sixteen floating, box type emergence traps, each covering 0.1 m², were placed along 150 m of a third-order stretch of the Bigoray River, a slow-flowing, vegetation-choked, brown-water muskeg stream. Effects of trap design, trap shading, length of sampling interval, and stream velocity on the number of midges caught was examined. Of the 112 species of Chironomidae caught, 32 species made up 90% of the catch and their emergence phenology is described in detail. There were more rare species than expected from Preston's lognormal distribution. Percentage of Bigoray species belonging to Tanypodinae, Orthocladiinae, Chironomini and Tanytarsini was 18%, 43%, 20%, and 19%, and was compared with 27 other studies on lotic chironomids. During the 140-day emergence period an average of 19.3 × 10³ chironomids emerged per square meter of stream. Based on changes in male:female ratios throughout a species emergence period, it was postulated that 30% of the Bigoray chironomid species were univoltine, 50% were bivoltine, and 20% were trivoltine.     

Impacts of fine sediment addition to tussock, pasture, dairy and deer farming streams in New Zealand

1. Increased fine sediment input caused by agricultural development is expected to act as a stressor for stream ecosystems. In a large‐scale field experiment, we added fine river sand to 50‐m reaches of three second‐order streams in each of four categories of catchment development (ungrazed tussock grasslands, grazed pasture, dairying and deer farming) and measured the responses of macroinvertebrates and aquatic moss. 2. Before addition, fine sediment cover differed between land uses, being lowest in tussock (7%), intermediate in pasture (30%) and dairy (47%) and highest in deer streams (88%). Sediment addition increased cover by one land‐use category (e.g. augmented sediment cover in tussock streams was similar to pre‐existing cover in pasture streams), and cover remained high in impact reaches (compared with controls) throughout the 5‐week experiment. Sediment addition did not change concentrations of phosphate, nitrate and ammonium, which were generally highest in dairy streams and lowest in tussock streams. 3. Aquatic mosses (most common in tussock, absent in dairy and deer), invertebrate density (highest in deer, lowest in tussock), taxon richness (highest in pasture, lowest in deer) and diversity (highest in pasture and tussock, lowest in dairy and deer) all differed between land uses. Sediment addition resulted in reductions of moss cover, invertebrate taxon richness and richness of Ephemeroptera, Plecoptera and Trichoptera in impact relative to control reaches. 4. The impact of sediment addition was strongest in pasture streams where pre‐existing sediment cover was moderate and richness and diversity of the invertebrate community highest. However, even in the already sediment‐rich and species‐poor deer streams, density of one common taxon was reduced significantly by sediment addition, and another two were affected in the same way in dairy streams, the second‐most intense land use. 5. Our experiment has disentangled the impact of sediment addition from other concomitant land‐use effects that could not be reliably distinguished in previous research, which has mainly consisted of correlative studies or unrealistically small‐scale experiments.     

Patterns and predictors of referral to the specialized chronic lymphocytic leukemia clinic in Manitoba,Canada

BackgroundBetter CLL patient survival has been reported for specialized CLL clinics/hematologists (compared to other CLL patients). It is possible that improved survival is driven by a better prognosis of referred patients.MethodsWe used logistic regression to calculate the odds ratios (ORs) and 95 % confidence intervals 95 %CIs) of the association between patient characteristics and CLL referral of all persons diagnosed in 2005–2016 with a pathologically-confirmed CLL or SLL.ResultsTwo-thirds of 1293 patients were referred to the CLL clinic. Referred patients were younger (16 % vs 44 % were 80 +) and in better health (47 % vs 56 % with a chronic diseases) than non-referred patients. Referral increased over time: in 2005–2010, about 60 % of patients were referred; in 2011–2016, this increased to 76 %. Gender did not affect referral (the OR for females is 1.0, 95 %CI 0.8–1.2), but age played a major role; CLL patients diagnosed at age 80 + were less likely to be referred than patients diagnosed < 60, 0.2 (0.1–0.3).ConclusionBecause referral to Manitoba’s specialized CLL clinic is associated with age and the patient’s overall health before referral, one should be careful in interpreting differences in outcomes between CLL patients based on referral status alone.     

Compositional changes and molecular transformations of dissolved organic matter during the arctic spring floods in the lower Churchill watershed (Northern Manitoba,Canada)

The spring flood season in Northern aquatic systems is characterized by rapid changes in river discharge and fluxes of organic and inorganic species, yet remains under sampled. In this study, we examine the molecular characteristics and transformations of dissolved organic matter (DOM) during the Arctic spring season at three locations in the lower Churchill River watershed. Characteristics including dissolved organic carbon concentrations, optical properties (i.e. absorbance and, excitation-emission matrix fluorescence coupled with parallel factor analysis, EEM-PARAFAC) and molecular characterization using high resolution mass spectrometry (HR-MS) were assessed. As spring floods progressed, a significant reduction in DOM spectral slope (S_275–295) and an increase in absorbance (a₂₇₀) were observed suggesting an increase in DOM molecular weight and concentrations at all sampled locations. A maximum in HR-MS lignin-class compounds coincided with peak flow at all sampled locations, further validated with an increase in PARAFAC humic-like components and a minimum in S_275–295. Principal component analyses revealed that both protein and aromatic humic-like material measured by HR-MS and EEM-PARAFAC, respectively, were significantly correlated (ANOVA, p < 0.05), demonstrating similarities in both techniques. Based on network analysis of HR-MS assigned formula, the highest peak flow day was characterized by a maximum in homologous DOM of C₂H₂O and C₂H₄ additions, suggesting structural similarities in newly deposited lignin and humic material. Overall, the progression of the spring freshet shifted the lower Churchill River watershed from an environment rich in proteins and lipids to an aquatic system more abundant in lignin, aromatic and humic DOM.     

Persistence in the desert: ephemeral waterways and small‐scale gene flow in the desert spring amphipod,Wangiannachiltonia guzikae

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Reverse engineering the embryo: a graduate course in developmental biology for engineering students at the University of Manitoba,Canada

Our desire to educate engineers to be able to understand the component processes of embryogenesis, is driven by the notion that only when principles borrowed from mathematics, fluid mechanics, materials science, etc. are applied to classical problems in developmental biology, will sufficient comprehension be achieved to permit successful understanding and therapeutic manipulation of embryos. As it now stands, biologists seldom possess either skills or interest in those areas of endeavor. Thus, we have determined that it is easier to educate engineers in the principles of developmental biology than to help biologists deal with the complexities of engineering. We describe a graduate course that has been taken, between 1999 and 2002, by 17 engineering students. Our goal is to prepare them to reverse engineer the embryo, i.e., to look at it as an object or process whose construction, albeit self-construction, might be explicable in terms of engineering principles applied at molecular, cellular and whole embryo levels.     

Exotic crayfish in a brown water stream: effects on juvenile trout, invertebrates and algae

SUMMARY 1. The impact of the introduced omnivorous signal crayfish (Pacifastacus leniusculus) on trout fry, macroinvertebrates and algae was evaluated in a brown water stream in southern Sweden using in situ enclosures. We also examined the gut content of all surviving crayfish in the enclosures. Two crayfish densities in addition to a control without crayfish were used in replicate enclosures (1.26 m²) in a 1‐month experiment. Additionally, 20 trout fry (Salmo trutta) were stocked in each enclosure to assess the effects of crayfish on trout survival and growth. 2. Detritus was the most common food item in crayfish guts. Animal fragments were also frequent while algae and macrophytes were scarcer. Crayfish exuviae were found in crayfish guts, but the frequency of cannibalism was low. 3. Trout survival in enclosures was positively related to water velocity but was unaffected by crayfish. 4. Total invertebrate biomass and taxon richness were lower in crayfish treatments. The biomass of all predatory invertebrate taxa was reduced but only three of six non‐predatory taxa were reduced in the crayfish treatments. 5. Epiphytic algal biomass (measured as chlorophyll a, on plastic strips) was not related to crayfish density, whereas the biomass of epilithic algae (measured as chlorophyll a) was enhanced by high water velocity and high crayfish density. The latter was possibly mediated via improved light and nutrient conditions, as active crayfish re‐suspend and/or remove detritus and senescent algal cells during periods of low water velocity. 6. We conclude that the introduced signal crayfish may affect stream communities directly and indirectly. Invaded communities will have reduced macroinvertebrate taxon richness and the signal crayfish will replace vulnerable invertebrate predators such as leeches. In streams that transport large amounts of sediment or organic matter, a high density of crayfish is likely to enhance benthic algal production through physical activity rather than via trophic effects.     

Population genetics and antibiotic susceptibility of invasive Haemophilus influenzae in Manitoba, Canada, from 2000 to 2006

One hundred and twenty-two isolates of Haemophilus influenzae causing invasive disease were collected in Manitoba, Canada, from 2000 to 2006 and examined for serotype, biotype, sequence type (ST) by multilocus sequence typing and antibiotic susceptibility. Nonserotypeable (NST) isolates accounted for over half of the isolates collected (69 isolates, 56.6%). There were 36 serotype a, five serotype b, two serotype c, one serotype d, four serotype e and five serotype f isolates collected. The 69 NST isolates were found to be very diverse, with isolates representing six biotypes and 45 STs. The serotypeable isolates were more clonal, with each of the serotypes showing little diversity in their biotypes and STs. Of the 122 isolates, 17% were resistant to ampicillin due to beta-lactamase production, 10.7% were resistant to trimethoprim-sulfamethoxazole, 1.6% were resistant to clarithromycin, 2.5% were resistant to amoxicillin-clavulanic acid and none was resistant to ciprofloxacin or moxifloxacin. Antibiotic resistance was more common in the NST strains, with 37.7% showing resistance to at least one antibiotic compared to 15% in the serotypeable strains. The results of this study suggest a shift in the epidemiology of invasive H. influenzae infections in the post-Hib vaccine era, and surveillance should include all serotypeable and NST isolates.     

Individual and combined effects of fish predation and bed disturbance on stream benthic communities: a streamside channel experiment

1. The composition and spatiotemporal dynamics of biological communities are influenced by biotic processes, such as predation and competition, but also by physical disturbances, such as floods in running waters. However, the interplay of disturbance with predation is still poorly understood, especially in frequently disturbed streams. Further, different predator species can affect prey communities in different ways depending on their feeding mode and efficiency. 2. We investigated the individual and combined effects of flood‐induced bed disturbance and fish predation on the benthos for 4 weeks in 18 streamside channels fed by a flood‐prone New Zealand river. Bed movements caused by floods were simulated by tumbling the substratum in half the channels. Six channels each were stocked with introduced brown trout (Salmo trutta) or native upland bully (Gobiomorphus breviceps) or had fish excluded. We studied algal biomass and both invertebrate density and daytime activity on surface stones on several dates after the disturbance, invertebrate community composition in the substrata of the entire channels on day 28 and leaf decomposition rates over the 28‐day period. 3. Disturbance affected algal biomass and density, richness and activity of surface stone invertebrates, and overall density and richness of channel invertebrates. Presence or absence of fish, by contrast, did not influence overall invertebrate standing stocks when subsurface substrata were included but did affect invertebrate densities on surface stones in 45% of all analysed cases and invertebrate activity on surface stones in all cases. Leaf decomposition rates were not influenced at all by the experimental manipulations. 4. Native upland bullies featured more often than exotic brown trout in causing invertebrate density changes and equally often in causing changes to grazer behaviour. Overall, our results imply that fish predation can have strong effects on the benthic invertebrate community in frequently disturbed streams, especially via behavioural changes.     

Metabarcoding of freshwater invertebrates to detect the effects of a pesticide spill

Biomonitoring underpins the environmental assessment of freshwater ecosystems and guides management and conservation. Current methodology for surveys of (macro)invertebrates uses coarse taxonomic identification where species‐level resolution is difficult to obtain. Next‐generation sequencing of entire assemblages (metabarcoding) provides a new approach for species detection, but requires further validation. We used metabarcoding of invertebrate assemblages with two fragments of the cox1 “barcode” and partial nuclear ribosomal (SSU) genes, to assess the effects of a pesticide spill in the River Kennet (southern England). Operational taxonomic unit (OTU) recovery was tested under 72 parameters (read denoising, filtering, pair merging and clustering). Similar taxonomic profiles were obtained under a broad range of parameters. The SSU marker recovered Platyhelminthes and Nematoda, missed by cox1, while Rotifera were only amplified with cox1. A reference set was created from all available barcode entries for Arthropoda in the BOLD database and clustered into OTUs. The River Kennet metabarcoding produced matches to 207 of these reference OTUs, five times the number of species recognized with morphological monitoring. The increase was due to the following: greater taxonomic resolution (e.g., splitting a single morphotaxon “Chironomidae” into 55 named OTUs); splitting of Linnaean binomials into multiple molecular OTUs; and the use of a filtration‐flotation protocol for extraction of minute specimens (meiofauna). Community analyses revealed strong differences between “impacted” vs. “control” samples, detectable with each gene marker, for each major taxonomic group, and for meio‐ and macrofaunal samples separately. Thus, highly resolved taxonomic data can be extracted at a fraction of the time and cost of traditional nonmolecular methods, opening new avenues for freshwater invertebrate biodiversity monitoring and molecular ecology.