Lowland Streams Research Articles

Do investments in water quality and habitat restoration programs pay off? An analysis of the chemical and biological water quality of a lowland stream in the Zwalm River basin (Belgium)

Early nineties of previous century aquatic biodiversity was low in many West-European countries as a consequence of pollution, hydromorphological degradation and a lack of sound environmental legislation. Since the early 2000s and the implementation of the European Water Framework Directive a big step forward has been made to achieve a good ecological status of surface waters in Europe. However, to date little is known about the response of biological life in small lowland streams on improving conditions for both water quality and habitat diversity. In this study, we assessed possible relationships between chemical water quality and aquatic biodiversity of the Zwalm River basin (Belgium) using a dataset of long-term measurements of the chemical and biological water quality. Specifically, we wanted to know 1) the evolution in chemical and biological water quality over the last three decades and 2) if an improvement in chemical water quality was reflected in the macroinvertebrate and fish diversity. We found that there was indeed a significant improvement in the chemical water quality thanks to the installation of wastewater treatment plants and river basin management plans. Shortly after this improvement in chemical water quality, an increase in the number and abundance of pollution sensitive macroinvertebrate taxa was observed, which was consequently also seen in the biotic index score, based on macroinvertebrates. Despite a limited change in community composition observed for fish, no significant increase in diversity, or in the biotic index score of fish could be found. Currently, a stagnation of the improving water quality is observed. Hydromorphological restoration and free fish migration remain important key factors to improve diversity of macroinvertebrates and fish species. Based on the results of this study, we provide guidelines (for example restoration of spawning beds, decrease diffuse pollution from agriculture) to optimize the investments made in river restoration and to achieve the good ecological status by 2027 as defined by the European Water Framework Directive.

Drought effects on invertebrate metapopulation dynamics and quasi-extinction risk in an intermittent river network.

Ecological communities can remain stable in the face of disturbance if their constituent species have different resistance and resilience strategies. In turn, local stability scales up regionally if heterogeneous landscapes maintain spatial asynchrony across discrete populations-but not if large-scale stressors synchronize environmental conditions and biological responses. Here, we hypothesized that droughts could drastically decrease the stability of invertebrate metapopulations both by filtering out poorly adapted species locally, and by synchronizing their dynamics across a river network. We tested this hypothesis via multivariate autoregressive state-space (MARSS) models on spatially replicated, long-term data describing aquatic invertebrate communities and hydrological conditions in a set of temperate, lowland streams subject to seasonal and supraseasonal drying events. This quantitative approach allowed us to assess the influence of local (flow magnitude) and network-scale (hydrological connectivity) drivers on invertebrate long-term trajectories, and to simulate near-future responses to a range of drought scenarios. We found that fluctuations in species abundances were heterogeneous across communities and driven by a combination of hydrological and stochastic drivers. Among metapopulations, increasing extent of dry reaches reduced the abundance of functional groups with low resistance or resilience capacities (i.e. low ability to persist in situ or recolonize from elsewhere, respectively). Our simulations revealed that metapopulation quasi-extinction risk for taxa vulnerable to drought increased exponentially as flowing habitats contracted within the river network, whereas the risk for taxa with resistance and resilience traits remained stable. Our results suggest that drought can be a synchronizing agent in riverscapes, potentially leading to regional quasi-extinction of species with lower resistance and resilience abilities. Better recognition of drought-driven synchronization may increase realism in species extinction forecasts as hydroclimatic extremes continue to intensify worldwide.

Through the dam into troubled waters: Combined effects of stream fragmentation, habitat deterioration, and poor water quality on lowland stream fish distribution

AbstractThis study aimed to distinguish the contribution of stream fragmentation and poor habitat and water quality to the decline in riverine fish species. The species presence was related to the number of barriers between a specific lowland stream section and the main river and to the length of the stream section remaining between two barriers. To investigate the relationship between the absence of fish species and poor ecological water quality, the EQR and stream velocity indices were compared between accessible sites where the fish was either present or absent. 79% of the 1039 km lowland stream length was disconnected from the river Meuse by one or more barriers and 34% by more than 5 barriers, while 28% of all stream sections were shorter than 2.5 km. Only 2% of sites scored a very good water quality, while all study sites were characterized by (very) slow flowing waters (<0.15 m/s). As many fish passages are built to improve connectivity, fish passages do not improve habitat quality. Gudgeon and stone loach were hardly affected by stream fragmentation, and only slightly by too short stream sections. Ide was moderately affected, while the migratory species chub and dace were severely affected by stream fragmentation. Chub and dace were also sensitive to poor habitat and water quality. Distinguishing the effects of stream fragmentation, habitat deterioration, and poor water quality on lowland stream fish distribution increased the understanding of the reasons for the presence and absence of species and may aid effective management and restoration efforts.

Sediment and Nutrient Retention in Ponds on an Agricultural Stream: Evaluating Effectiveness for Diffuse Pollution Mitigation

The creation of ponds and wetlands has the potential to alleviate stream water quality impairment in catchments affected by diffuse agricultural pollution. Understanding the hydrological and biogeochemical functioning of these features is important in determining their effectiveness at mitigating pollution. This study investigated sediment and nutrient retention in three connected (on-line) ponds on a lowland headwater stream by sampling inflowing and outflowing concentrations during base and storm flows. Sediment trapping devices were used to quantify sediment and phosphorus accumulations within ponds over approximately monthly periods. The organic matter content and particle size composition of accumulated sediment were also measured. The ponds retained dissolved nitrate, soluble reactive phosphorus and suspended solids during baseflows. During small to moderate storm events, some ponds were able to reduce peak concentrations and loads of suspended solids and phosphorus; however, during large magnitude events, resuspension of deposited sediment resulted in net loss. Ponds filtered out larger particles most effectively. Between August 2019 and March 2020, the ponds accumulated 0.306 t ha−1 sediment from the 30 ha contributing area. During this period, total sediment accumulations in ponds were estimated to equal 7.6% of the suspended flux leaving the 340 ha catchment downstream. This study demonstrates the complexity of pollutant retention dynamics in on-line ponds and highlights how their effectiveness can be influenced by the timing and magnitude of events.

Incidence of Watershed Land Use on the Consumption of Meso and Microplastics by Fish Communities in Uruguayan Lowland Streams

Physical-chemical and biologicaldiversity of streams are influenced by the land use in their watersheds. Plastics currently make up the most important waste asset, representing an important part of the transported and accumulated material in water courses. This work analyzes the consumption of plastics debris by the fish communities in streams with two contrasting types of land use. We worked with threestreams impacted by urbanization and threeby extensive ranching. The stomach and intestinal contents of 309 individuals of 29 species were analyzed, by a modified alkaline digestion, and observed under a stereo microscope with polarized light. A total of 373 plastic itemswere found, of which the majority corresponded to fibers (318). A significant difference was found between the percentage of individuals that consumed plastic debrisbetween both systems (51.6% in ranchers and 76.6% in urban, p = 0.014 Mood’s Median), but no difference was found in the average ingested per individual. This study establishes the first baseline on plastic debris consumption by fish in Uruguayan streams, showing the extent of the plastic and microplastic pollution problem. Although there are differences between the analyzed sites, we also observed significant contamination in streams far from urbanization.

Pesticides are the dominant stressors for vulnerable insects in lowland streams

Despite elaborate regulation of agricultural pesticides, their occurrence in non-target areas has been linked to adverse ecological effects on insects in several field investigations. Their quantitative role in contributing to the biodiversity crisis is, however, still not known. In a large-scale study across 101 sites of small lowland streams in Central Europe, Germany we revealed that 83% of agricultural streams did not meet the pesticide-related ecological targets. For the first time we identified that agricultural nonpoint-source pesticide pollution was the major driver in reducing vulnerable insect populations in aquatic invertebrate communities, exceeding the relevance of other anthropogenic stressors such as poor hydro-morphological structure and nutrients. We identified that the current authorisation of pesticides, which aims to prevent unacceptable adverse effects, underestimates the actual ecological risk as (i) measured pesticide concentrations exceeded current regulatory acceptable concentrations in 81% of the agricultural streams investigated, (ii) for several pesticides the inertia of the authorisation process impedes the incorporation of new scientific knowledge and (iii) existing thresholds of invertebrate toxicity drivers are not protective by a factor of 5.3 to 40. To provide adequate environmental quality objectives, the authorisation process needs to include monitoring-derived information on pesticide effects at the ecosystem level. Here, we derive such thresholds that ensure a protection of the invertebrate stream community.

A river classification scheme to assess macroinvertebrate sensitivity to water abstraction pressures

AbstractThe concept of environmental flows has been developed to manage human alteration of river flow regimes, as effective management requires an understanding of the ecological consequences of flow alteration. This study explores the concept of macroinvertebrate sensitivity to river flow alteration to establish robust quantitative relationships between biological indicators and hydrological pressures. Existing environmental flow classifications used by the environmental regulator for English rivers were tested using multilevel regression modelling. Results showed a weak relationship between the current abstraction sensitivity classification and macroinvertebrate response to flow pressure. An alternative approach, based on physically derived river types, was a better predictor of macroinvertebrate response. Intermediate sized lowland streams displayed the best model fit, while upland rivers exhibited poor model performance. A better understanding of the ecological response to flow variation in different river types could help water resource managers develop improved ecologically appropriate flow regimes, which support the integrity of river ecosystems.

Riparian forests buffer the negative effects of cropland on macroinvertebrate diversity in lowland Amazonian streams

Riparian forests regulate stream ecosystems and biodiversity. Therefore, changes to riparian structure may threaten stream ecosystem function by triggering taxonomic and functional changes to aquatic communities. Because macroinvertebrate assemblages are sensitive to environmental changes, they can be effective indicators of stream integrity in disturbed landscapes. To assess the role of riparian forests in maintaining tropical stream communities in areas experiencing large-scale watershed disturbance, we quantified the taxonomic and functional response of stream macroinvertebrate communities to forest clearing in the southeastern Amazon’s agricultural frontier, a region experiencing widespread deforestation. Our results show that watershed deforestation can lead to significant changes in macroinvertebrate richness and community composition. We found a predominance of shredders in forested watersheds; scrapers in cropland watersheds with riparian forests; and collector-filterers in cropland watersheds without riparian forest buffers. Taxonomic composition was controlled by available organic material in forested watersheds and by periphyton in cropland sites regardless of whether they had a riparian buffer. Our results show that the clearing of riparian forests alters food sources supporting aquatic food webs, leading to ecosystem-level shifts through changes in light and temperature dynamics that affect aquatic communities in areas with intense land-use change such as the southeastern Amazon.

Self-dynamics as a driver for restoration success in a lowland stream reach

Multiple stressors like alterations of water quality, hydrology and hydromorphology impact riverine ecosystems. To counteract its consequences, restoration measures are required, e.g. demanded by the EU Water Framework Directive. However, small-scale hydromorphological restoration measures often show little success. Besides overriding stressors, recolonization potential and insufficient time for development are often discussed as reasons for this lack of success. Over a period of 17 years a hydromorphological restoration measure in a German lowland stream reach was evaluated, excluding most of these confounding factors. The restoration measure was left to its self-dynamic development, i.e. there was no further intervention by water management, apart from some large wood installations after 8 years. In the accompanying studies, changes in hydromorphology and the organism groups macroinvertebrates (including both structural and functional diversities), fish and macrophytes were investigated.We proved a rapid and stable enhancement of ecological functions as indicated by a diverse and resilient macroinvertebrate biocoenosis. Both taxonomic and functional richness of macroinvertebrates significantly increased, but varied over time. Since the restoration measure allowed self-dynamic development, a taxonomic and functional endpoint was not achieved even after 17 years, even though near-reference conditions were attained after only 4 years. Deficits in fish communities were most probably due to their low recolonization potential.Our results underscore that small scale hydromorphological restoration can be successful if overriding stressors are absent. Furthermore, we proved the importance of self-dynamics in restoration measures, allowing hydromorphological and biological development.

Strategies of shredders when feeding on low‐quality leaf‐litter: Local population adaptations or fixed species traits?

AbstractThe linkage between leaf‐litter and macroinvertebrate shredders is pivotal for stream food webs. Global change is predicted to decrease the nutritional quality of litter inputs to streams. However, little is known about shredder's ability to develop local interpopulation adaptations to face nutrient‐depleted leaf‐litter. We hypothesized that this adaptation could be present in populations receiving low‐quality leaf‐litter. We performed feeding tests on three abundant shredders species from lowland (a snail) and mountain (two insects) streams. Two populations of each species were derived from two subregions contrasting in average quality of litter inputs. Individuals were fed on four diets of contrasting quality: two leaf‐litter species with two qualities each, and their feeding rates, survivorship, growth, and energetic storage were evaluated. Results suggest that local population adaptation to low‐quality litters is not common, being essentially a fixed species trait that varies across species, in particular among snails and insects. The ability of the snail to cope with low‐quality litters suggests that ecosystem processes in lowland streams may resist reductions in litter quality. Conversely, potential alterations of riparian vegetation linked to global changes might disrupt mountain stream ecosystem functioning.

Phosphorus Transport in a Lowland Stream Derived from a Tracer Test with 32P

Small streams in urbanized rural areas receive loads of P from various, often episodic, sources. This paper addresses, through a tracer test with 32P, retention and transport of a pulse input of phosphorus in a 2.6 km long stretch of a channelized second-order lowland stream. Tritiated water was introduced alongside the 32P-labelled ortophosphate in order to isolate the influence of the hydrodynamic factors on P behavior. Tracer concentrations in unfiltered water samples were measured by liquid scintillation counting. Four in-stream and five hyporheic breakthrough curves were collected at four points along the stream, two of which encompass a beaver dam impoundment. The overall retention efficiency of 32P along the studied reach was 46%. The transient storage transport model OTIS-P provided reasonable fits for in-stream breakthrough curves (BTCs) but failed at reproducing the hyporheic BTCs. The overall small effect of transient storage on solute transport was higher in the stretch with a more pronounced surface storage. Transient storage and phosphorus retention were not enhanced in the beaver dam impoundment.

Effects of experimental flow manipulations on water quality, hypoxia, and growth of Threatened Salish sucker (Catostomus sp. cf. catostomus) and juvenile coho salmon (Oncorhynchus kisutch)1

The Salish sucker (Catostomus sp. cf. catostomus) is a federally Threatened species in Canada, inhabiting small lowland streams along with juvenile coho salmon (Oncorhynchus kisutch) in southwestern British Columbia and adjacent Washington State. Experiments were conducted in two ponds to determine the effects of reduced flow on dissolved oxygen, growth of stocked Salish sucker and juvenile coho salmon (Oncorhynchus kisutch), and fish movement using passive integrated transponder (PIT) tags. Sequential flow reduction in the first experiment resulted in a significant decrease in dissolved oxygen (9.1 to 3.1 mg·L−1) and Salish sucker growth (23% decline), although lower dissolved oxygen and growth were confounded with decreased temperature. Flow reduction in a second split-pond experiment including coho salmon resulted in significantly lower dissolved oxygen (6.9 to 2.9 mg·L−1), a 51% reduction in growth of coho salmon, but no detectable change in Salish sucker growth. PIT tag detections demonstrated increased use by both species of a well-oxygenated refuge in the flow reduction treatment, indicating sublethal effects of hypoxia on fish behaviour and habitat use. These experiments demonstrate the induction of severe hypoxia by reduced flows under eutrophy, with the potential for negative impacts on Salish sucker and juvenile coho salmon growth and habitat use.

Surprising Pseudogobius: Molecular systematics of benthic gobies reveals new insights into estuarine biodiversity (Teleostei: Gobiiformes)

Snubnose gobies (genus Pseudogobius: Gobionellinae) are ubiquitous to, and important components of, estuarine ecosystems of the Indo-west Pacific. These small benthic fishes occur in freshwater, brackish and marine habitats such as mangroves, sheltered tide pools and lowland streams, and represent a model group for understanding the biodiversity and biogeography of estuarine fauna. To develop the species-level framework required for a concurrent morphological taxonomic appraisal, we undertook thorough sampling around the extensive Australian coastline, referenced to international locations, as part of a molecular systematic review using both nuclear and mitochondrial markers. The results indicate that while there are currently eight recognised species, the true diversity is close to double this, with a hotspot of endemism located in Australia. Complicated patterns were observed in southern Australia owing to two differing zones of introgression/admixture. Key drivers of diversity in the group appear to include plate tectonics, latitude, and historic barriers under glacial maxima, where an interplay between ready dispersal and habitat specialisation has led to regional panmixia but frequent geographic compartmentalisation within past and present landscapes. The findings have significant implications for biodiversity conservation, coastal and estuarine development, the basic foundations of field ecology, and for applied use such as in biomonitoring.

Strong influence of climatic extremes on diversity of benthic algae and cyanobacteria in a lowland intermittent stream

AbstractFreshwater ecosystems are threatened by the global change‐induced extreme climatic events worldwide. The unpredictable changes in water supply create strongly disturbed environments and ultimately result in diversity changes. Here, we studied the formation of benthic algal and cyanobacterial assemblages under intermediately disturbed (IDC) and highly disturbed conditions (HDC) in a small lowland intermittent stream. We addressed our hypotheses to the Intermediate Disturbance Theory supposing that intermediate frequencies or intensities of disturbances maximise diversity independently of its level. We expected a larger influence of extremes in water supply on functional than on taxonomic and phylogenetic diversity. Our results only partially proved our first hypothesis highlighting the (i) importance of short‐time but intense disturbing effect on biofilm formation and trait composition under IDC period and (ii) the instability within the assemblages caused by large and opposing influences during HDC. Although extreme weather events caused trait extremes (supporting second hypothesis), they did not result in a decrease in functional richness (rejecting the second hypothesis). These findings in accordance with the insurance hypothesis clearly stress that a system with high functional redundancy can keep its functionality even under drastic hydrological conditions and the accompanying loss of species.

Influence of plant habitats on denitrification in lowland agricultural streams

The aim of this study was to assess potential differences in denitrification in contrasting stream habitats in agricultural lowland streams located in Denmark. The study focused on three types of habitats i) vegetated habitats with emergent plants, ii) vegetated habitats with submerged plants, iii) bare sediments. Denitrification rates were measured in situ using denitrification chambers and nitrogen isotope pairing technique three times during a growing season. Denitrification rates across all habitats and samplings were 73 ± 116 μmol N m−2 h−1 (mean ± sd) with greater denitrification rates in vegetated habitats compared to bare sediments. Habitats with emergent plants had significantly higher denitrification rates than habitats with submerged plants. The habitats exhibited differences in oxygen and carbon availability probably connected to differences in flow velocity and physical effect of the vegetation (if present) which likely acted as a trap for finer organic-rich particles. Placing these results in the context of stream and river restoration highlights the potential of in-stream vegetation to mitigate nitrogen pollution, especially by restoring plant habitats in degraded and channelized streams to sustain vegetation promoting higher denitrification rates.

A Bayesian network to simulate macroinvertebrate responses to multiple stressors in lowland streams

Aquatic ecosystems are affected by multiple environmental stressors across spatial and temporal scales. Yet the nature of stressor interactions and stressor-response relationships is still poorly understood. This hampers the selection of appropriate restoration measures. Hence, there is a need to understand how ecosystems respond to multiple stressors and to unravel the combined effects of the individual stressors on the ecological status of waterbodies. Models may be used to relate responses of ecosystems to environmental changes as well as to restoration measures and thus provide valuable tools for water management. Therefore, we aimed to develop and test a Bayesian Network (BN) for simulating the responses of stream macroinvertebrates to multiple stressors. Although the predictive performance may be further improved, the developed model was shown to be suitable for scenario analyses. For the selected lowland streams, an increase in macroinvertebrate-based ecological quality (EQR) was predicted for scenarios where the streams were relieved from single and multiple stressors. Especially a combination of measures increasing flow velocity and enhancing the cover of coarse particulate organic matter showed a significant increase in EQR compared to current conditions. The use of BNs was shown to be a promising avenue for scenario analyses in stream restoration management. BNs have the capacity for clear visual communication of model dependencies and the uncertainty associated with input data and results and allow the combination of multiple types of knowledge about stressor-effect relations. Still, to make predictions more robust, a deeper understanding of stressor interactions is required to parametrize model relations. Also, sufficient training data should be available for the water type of interest. Yet, the application of BNs may now already help to unravel the contribution of individual stressors to the combined effect on the ecological quality of water bodies, which in turn may aid the selection of appropriate restoration measures that lead to the desired improvements in macroinvertebrate-based ecological quality.

Size‐dependent sensitivity of stream amphipods indicates population‐level responses to chemical pollution

Abstract Global change assessments have typically ignored synthetic chemical pollution, despite the rapid increase of pharmaceuticals, pesticides, and industrial chemicals in the environment. The paucity of research on the ecological effects of these micropollutants undermines our efforts to address the freshwater biodiversity crisis. Understanding the responses of individual organisms to chemical pollution should help address this knowledge gap because individual‐level effects can cascade across populations, communities, and ecosystems with devastating consequences. Inputs of treated municipal wastewater are a major source of micropollutants in receiving environments. Here, we assessed population and individual‐level influences of treated wastewater on freshwater gammarid amphipods (Gammarus spp.) in Swiss lowland streams in situ and tested effects of a micropollutant mixture on individual Gammarus fossarum using a common garden laboratory experiment. We hypothesised that population‐level effects of wastewater are mediated through asymmetric sensitivities of juvenile and adult gammarids to chemical pollutants. We expected that life‐stage specific sensitivities would reflect allometric theory relating body size to a wide range of organismal characteristics, including metabolism, growth, and mortality. At the population level (i.e. field survey), we observed greatly reduced abundances of juvenile gammarids downstream of the wastewater discharge in three of the six sites surveyed, indicating the potential for demographic effects of pollution. At the individual level in a field transplant experiment, we found that the presence of wastewater led to a steeper positive relationship between gammarid body size and leaf consumption. In the laboratory experiment, we found that micropollutants had negative effects on consumption and growth rates, but a positive effect on survival. Differences in the relationship between gammarid body size and performance were subtle across treatments, although flatter slopes in growth appear to be a consistent response to chemical pollution. Faster growth rates appeared to be connected with reduced survival, placing individuals in control treatments and/or with smaller body size at greatest risk of mortality. Notably, juvenile gammarids had faster growth rates and lower survival than adults when exposed to micropollutants. Our results demonstrate the potential for negative impacts of micropollutants in freshwater ecosystems. However, the results also show that organismal responses to chemical pollutants can be complex, whereby impacts at the individual level may act counter‐intuitively to population‐level dynamics. This highlights the need for more realistic experiments to better assess how organismal responses depend on life stage and body size, and how individual‐level effects propagate to higher levels of biological organisation. Our study shows how allometric theory can be used to examine the effects of stressors on underlying organismal biology, population demographics, and link with broader macroecological patterns.

Transplanting macrophytes as a rehabilitation technique for lowland streams and their influence on macroinvertebrate assemblages.

Lowland streams are usually affected by river engineering works that produce the loss of habitat heterogeneity. Our aim was to assess the transplantation of macrophytes with different complexity into a lowland stream which was dredged and widened. Stuckenia pectinata and Hydrocleys nymphoides were collected at an extraction site and installed at a transplant site. The growth and coverage of macrophytes beds were quantified. Taxonomic richness, Shannon-Wiener diversity, abundance, composition and proportion of functional feeding groups of the macroinvertebrate assemblage presented in macrophyte beds were assessed between sites and species. The growth of both macrophytes did not differ significantly between sites and the coverage of transplanted beds increased, therefore they established at the transplant site within a short period. Regarding to macroinvertebrate assemblage, only the functional feeding groups did not show differences between sites. Moreover, the proportion of predators presented differences between macrophytes at the same site, with H. nymphoides having a higher proportion. Our study showed that this technique is suitable for reintroducing these species and is applicable in rehabilitation projects that promote the restoration of habitat heterogeneity deteriorated by river engineering works. Also, we highlight the importance of incorporate macroinvertebrate functional traits to assess the ecological status after rehabilitation.

Alkalinity and Diatom Assemblages in Lowland Streams: How to Separate Alkalinity from Inorganic Phosphorus in Ecological Assessments?

Alkalinity and Diatom Assemblages in Lowland Streams: How to Separate Alkalinity from Inorganic Phosphorus in Ecological Assessments?

Effects of different weed cutting methods on physical and hydromorphological conditions in lowland streams

Climate change has increased the frequency and intensity of stream flooding events. In response, managing authorities may increase frequency and intensity of aquatic plant removal (weed cutting) to lower the water level in rivers possibly impairing physical and hydromorphological stream conditions. We studied 32 Danish lowland streams subjected to three different weed cutting practices, representing a gradient in weed cutting intensity, and uncut controls to compare physical and hydromorphological habitat quality parameters among stream groups. Moreover, we measured short-term changes in dissolved oxygen (DO) concentrations and suspended sediment (SS) transport in two streams before, during, and just after weed cutting for the least and most pervasive weed cutting method, respectively. Our results indicated a lower habitat quality affiliated with increasing intensity of weed cutting practice, notably an association with silt cover at the expense of hard substrate. DO concentrations were relatively unaltered but an abrupt increase in SS transport comparable to storm events was observed during cutting with the most pervasive method. Our results indicate that ecological and hydromorphological effects of high intensity weed cutting should be carefully studied and considered before large scale implementation.