Ecological Status Of Streams Research Articles

Mine Wastewater Effect on the Aquatic Diversity and the Ecological Status of the Watercourses in Southern Poland

Coal mining activity contributes to energy security and employment occupation, but is associated with environmental deterioration. Coal combustion leads to GHG emissions, while coal mining results in the generation of saline effluents. These effluents are discharged in inland surface waters, applying significant pressure on their quality, with a negative impact on aquatic life and the economy of a region. This study includes water samples that were analyzed in order to investigate the organic compounds, heavy metals, and other physicochemical parameters. Biological monitoring was done according to the Water Framework Directive methodology. The results from an aquatic area in Southern Poland, which indirectly receives coal mine effluents, indicate elevated salinity with excessive chlorides, sulfates, and sodium ions. The water quality of another non-polluted aquatic area was also assessed to examine the impact of indirect coal mine wastewater discharge on this area. The high salinity levels hinder the use of river water for drinking, agricultural, or industrial purposes. The results obtained show high pressure on the ecological status of streams and rivers that receive mine effluents, and on the density and diversity of aquatic invertebrates. This pressure is clearly visible in the structure of benthic communities and in invertebrate diversity. It also contributes to the appearance of invasive species and increasing water salinity. Limiting discharges of mine water transporting large loads of saline substances would reduce the negative impact on the quality of river waters and biological life.

Rehabilitation of tropical urban streams improves their structure and functioning

Urban streams are affected by a complex combination of stressors, which modify physical habitat structure, flow regime, water quality, biological community composition, and ecosystem processes and services, thereby altering ecosystem structure and functioning. Rehabilitation projects have been undertaken in several countries to rehabilitate urban streams. However, stream rehabilitation is still rarely reported for neotropical regions. In addition, most studies focus on structural aspects, such as water quality, sediment control, and flood events, without considering ecosystem function indicators. Here, we evaluated the structure and functioning of three 15-y old rehabilitated urban stream sites in comparison with three stream sites in the best available ecological condition (reference), three sites with moderate habitat alteration, and three severely degraded sites. Compared to degraded streams, rehabilitated streams had higher habitat diversity, sensitive macroinvertebrate taxa richness, and biotic index scores, and lower biochemical oxygen demand, primary production, sediment deposition, and siltation. However, rehabilitated streams had higher primary production than moderate and reference streams, and lower canopy cover, habitat diversity, sensitive macroinvertebrate taxa richness, and biotic index scores than reference streams. These results indicate that rehabilitated streams have better structural and functional condition than degraded streams, but do not strongly differ from moderately altered streams, nor have they reached reference stream condition. Nonetheless, we conclude that rehabilitation is effective in removing streams from a degraded state by improving ecosystem structure and functioning. Furthermore, the combined use of functional and structural indicators facilitated an integrative assessment of stream ecological condition and distinguished stream conditions beyond those based on water quality indicators.

A diatom-based approach to refine nutrient concentrations compatible with the “good” status of Northern Italy rivers

The identification of ecologically sound thresholds represents an important step toward improving the ecological status of rivers through appropriate measures to contain nutrient loads. The aim of the present study was to estimate phosphorus and nitrogen concentrations compatible with the achievement of the “good” ecological status of rivers from data collected in the Po River District, the largest hydrographic system in Italy. For this purpose, relationships between the diatom index used in Italy for the national assessment of the stream ecological status, the ICMi (Intercalibration Common Metric index), and total phosphorus and nitrate concentrations were analyzed using monitoring data collected between 2009 and 2019. The Po River Basin encompasses five distinct river types, from Alpine to Mediterranean to Lowlands, characterized by different anthropogenic pressures and water quality. Through regression analysis between the ICMi and nutrient concentrations, we estimated ranges of the latter values corresponding to a “good” ecological status for each river type. The resulting thresholds are far more stringent than the limits set by the Italian legislation for water quality classification. This is particularly true for total phosphorus, whose threshold value should be roughly halved for all river types. For nitrates, the results are more differentiated according to river type: the estimated thresholds are much more stringent than those currently in use for siliceous Alpine and Mediterranean rivers. Moreover, the availability of such a large database allowed also to assess the influence of one nutrient over the other on the diatom community and to highlight some critical issues in the formulation of ICMi for Mediterranean rivers.

Anthropogenic land uses influence stream dissolved organic matter quality more than decomposition rates and macroinvertebrate diversity

In the era of the Anthropocene, streams and rivers are among the most heavily impacted ecosystems due to the influence of catchment land use on stream water quality and ecological condition. In practice, structural and functional indicators collected by biomonitoring programs are underused and thus limited in their ability to offer practical insight into functional-based restoration approaches. Here we applied a novel combination of indicators—cotton strip decomposition, benthic invertebrate sampling together with dissolved organic matter (DOM) composition — to determine if streams highly impacted by urbanized and agricultural land use across Windsor-Essex (southwestern Ontario, Canada) were consistent across season, anthropogenic land use or some combination of both. Overall, our results suggest that urbanized and agricultural streams are indeed degraded at a similar level, with high decomposition rates and low levels of macroinvertebrate diversity. Moreover, DOM quality proved to be the most predictable indicator spatially and seasonally, integrating insights from both decomposition and macroinvertebrate indices. Microbial humic-like DOM correlated positively with decomposition rates, and negatively with invertebrate species richness. Our findings show that functional changes in stream ecological condition can be effectively tracked by structural indicators, namely DOM composition. DOM offers a cost-effective approach to assessing ecosystem health and should be explored as a reliable indicator in monitoring programs and to inform functional-based indicators in ecosystem restoration.

The Roles of Microbes in Stream Restorations.

The goods and services provided by riverine systems are critical to humanity, and our reliance increases with our growing population and demands. As our activities expand, these systems continue to degrade throughout the world even as we try to restore them, and many efforts have not met expectations. One way to increase restoration effectiveness could be to explicitly design restorations to promote microbial communities, which are responsible for much of the organic matter breakdown, nutrient removal or transformation, pollutant removal, and biomass production in river ecosystems. In this paper, we discuss several design concepts that purposefully create conditions for these various microbial goods and services, and allow microbes to act as ecological restoration engineers. Focusing on microbial diversity and function could improve restoration effectiveness and overall ecosystem resilience to the stressors that caused the need for the restoration. Advances in next-generation sequencing now allow the use of microbial 'omics techniques (e.g., metagenomics, metatranscriptomics) to assess stream ecological conditions in similar fashion to fish and benthic macroinvertebrates. Using representative microbial communities from stream sediments, biofilms, and the water column may greatly advance assessment capabilities. Microbes can assess restorations and ecosystem function where animals may not currently be present, and thus may serve as diagnostics for the suitability of animal reintroductions. Emerging applications such as ecological metatranscriptomics may further advance our understanding of the roles of specific restoration designs towards ecological services as well as assess restoration effectiveness.

Why wastewater treatment fails to protect stream ecosystems in Europe

There is significant debate about why less than half of European rivers and streams are in good ecological status, despite decades of intense regulatory efforts. Of the multiple stressors that are recognized as potential contributors to stream degradation, we focus on discharge from 26,500 European wastewater treatment plants (WWTPs). We tested the hypothesis that stream ecological status degradation across Europe is related to the local intensity of wastewater discharge, with an expected stream-order (ω) dependence based on the scaling laws that govern receiving stream networks. We found that ecological status in streams (ω≤3) declined consistently with increasing urban wastewater discharge fraction of stream flow (UDF) across river types and basins. In contrast, ecological status in larger rivers (ω≥4) was not related to UDF. From a continental-scale logistic regression model (accuracy 86%) we identified an ecologically critical threshold UDF = 6.5% ± 0.5. This is exceeded by more than one third of WWTPs in Europe, mostly discharging into smaller streams. Our results suggest that new receiving water-specific strategies for wastewater management are needed to achieve good ecological status in smaller streams.

Small stream catchments in a developing city context: The importance of land cover changes on the ecological status of streams and the possibilities for providing ecosystem services

Urban expansion and the transformation of rural areas into suburban areas along with increasing human pressure can cause major changes in the environment. Typical effects of urbanization include degradation of aquatic ecosystems. However, urban expansion is often accompanied by an effort to provide residents with some contact with nature in the city. Natural waterbodies are the elements of the environment predestined to ensure appropriate conditions for recreation and other ecosystem services key to human well-being. In this study, the changes in the forms of development of a submontane stream catchment area (Carpathians, Poland) against the background of the gradual extension of city boundaries were analysed. In addition, the impact of urbanization on the ecological conditions of the urban stream, and therefore the potential ecosystem to provide ecosystem services, was assessed. Although the extension of the city entailed the development of settlements, it was accompanied by the expansion of the municipal sewage infrastructure, thus improving sewage management. The disappearance of arable lands from the stream catchment due to the decline in agricultural activities initiated the spontaneous process of buffer restoration along the stream. All the biotic indices such as Shannon diversity index, Margalef species richness index and BMWP-PL index, based on macroinvertebrate communities increased, and the fish were more numerous in the late stage of city development compared with the early (rural) stage. Surprisingly, the system has rehabilitated well with no revitalisation actions. It is necessary, however, to improve morphological in-stream conditions, and to make further efforts to improve water quality for the system to develop a semi-natural state. Only reaching full ecological potential can lead to an increase in the ecosystem capacity to provide ecosystem services. The studied ecosystem may provide many different services simultaneously, but their availability depends on the protection of the ecosystem's functioning as a whole.

Evaluating the impact of watershed development and climate change on stream ecosystems: A Bayesian network modeling approach

A continuous-variable Bayesian network (cBN) model is used to link watershed development and climate change to stream ecosystem indicators. A graphical model, reflecting our understanding of the connections between climate change, weather condition, loss of natural land cover, stream flow characteristics, and stream ecosystem indicators is used as the basis for selecting flow metrics for predicting macroinvertebrate-based indicators. Selected flow metrics were then linked to variables representing watershed development and climate change. We fit the model to data from two river basins in southeast US and the resulting model was used to simulate future stream ecological conditions using projected future climate and development scenarios. The three climate models predicted varying ecological condition trajectories, but similar worst-case ecological conditions. The established modeling approach couples mechanistic understanding with field data to develop predictions of management-relevant variables across a heterogeneous landscape. We discussed the transferability of the modeling approach.

Morphological vs. DNA metabarcoding approaches for the evaluation of stream ecological status with benthic invertebrates: Testing different combinations of markers and strategies of data filtering.

Macroinvertebrate assemblages are the most common bioindicators used for stream biomonitoring, yet the standard approach exhibits several time-consuming steps, including the sorting and identification of organisms based on morphological criteria. In this study, we examined if DNA metabarcoding could be used as an efficient molecular-based alternative to the morphology-based monitoring of streams using macroinvertebrates. We compared results achieved with the standard morphological identification of organisms sampled in 18 sites located on 15 French wadeable streams to results obtained with the DNA metabarcoding identification of sorted bulk material of the same macroinvertebrate samples, using read numbers (expressed as relative frequencies) as a proxy for abundances. In particular, we evaluated how combining and filtering metabarcoding data obtained from three different markers (COI: BF1-BR2, 18S: Euka02 and 16S: Inse01) could improve the efficiency of bioassessment. In total, 140 taxa were identified based on morphological criteria, and 127 were identified based on DNA metabarcoding using the three markers, with an overlap of 99 taxa. The threshold values used for sequence filtering based on the "best identity" criterion and the number of reads had an effect on the assessment efficiency of data obtained with each marker. Compared to single marker results, combining data from different markers allowed us to improve the match between biotic index values obtained with the bulk DNA versus morphology-based approaches. Both approaches assigned the same ecological quality class to a majority (86%) of the site sampling events, highlighting both the efficiency of metabarcoding as a biomonitoring tool but also the need for further research to improve this efficiency.

Benthic Diatom Communities in Urban Streams and the Role of Riparian Buffers

Urbanization impacts stream ecosystems globally through degraded water quality, altered hydrology, and landscape disturbances at the catchment and riparian scales, causing biodiversity losses and altered system functioning. Addressing the “urban stream syndrome” requires multiple mitigation tools, and rehabilitation of riparian vegetation may help improve stream ecological status and provide key ecosystem services. However, the extent to which forested riparian buffers can help support stream biodiversity in the face of numerous environmental contingencies remains uncertain. We assessed how a key indicator of stream ecological status, benthic diatoms, respond to riparian habitat conditions using 10 urban site pairs (each comprising of one unbuffered and one buffered reach), and additional urban downstream and forest reference upstream sites in the Oslo Fjord basin. Diatom communities were structured by multiple drivers including spatial location, land use, water quality, and instream habitat. Among these, riparian habitat condition independently explained 16% of variation in community composition among site pairs. Changes in community structure and indicator taxa, along with a reduction in pollution-tolerant diatoms, suggested tangible benefits of forested riparian buffers for stream biodiversity in urban environments. Managing urban impacts requires multiple solutions, with forested riparian zones providing a potential tool to help improve biodiversity and ecosystem services.

Microbial communities can predict the ecological condition of headwater streams.

Humanity's reliance on clean water and the ecosystem services provided makes identifying efficient and effective ways to assess the ecological condition of streams ever more important. We used high throughput sequencing of the 16S rRNA region to explore relationships between stream microbial communities, environmental attributes, and assessments of stream ecological condition. Bacteria and archaea in microbial community samples collected from the water column and from stream sediments during spring and summer were used to replicate standard assessments of ecological condition performed with benthic macroinvertebrate collections via the Benthic Index of Biotic Integrity (BIBI). Microbe-based condition assessments were generated at different levels of taxonomic resolution from phylum to OTU (Operational Taxonomic Units) in order to understand appropriate levels of taxonomic aggregation. Stream sediment microbial communities from both spring and summer were much better than the water column at replicating BIBI condition assessment results. Accuracies were as high as 100% on training data used to build the models and up to 80% on validation data used to assess predictions. Assessments using all OTUs usually had the highest accuracy on training data, but were lower on validation data due to overfitting. In contrast, assessments at the order-level had similar performance accuracy for validation data, and a reduced subset of orders also performed well, suggesting the method could be generalized to other watersheds. Subsets of the important orders responded similarly to environmental gradients compared to the entire community, where strong shifts in community structure occurred for known aquatic stressors such as pH, dissolved organic carbon, and nitrate nitrogen. The results suggest the stream microbes may be useful for assessing the ecological condition of streams and especially useful for stream restorations where many eukaryotic taxa have been eliminated due to prior degradation and are unable to recolonize.

Stream assessment goes local—identifying regional drivers of water quality to inform management for local watershed groups.

Two non-profit organizations in southwestern Pennsylvania requested water quality data for several local watersheds in need of conservation attention. We conducted a study to identify the primary drivers of stream ecological condition in each watershed to inform future management decisions. Our study consisted of land cover analysis, routine water chemistry monitoring and macroinvertebrate assessment of 20 stream sites within the Upper Ohio-Wheeling subbasin in southwestern Pennsylvania and the Northern Panhandle of West Virginia. We ranked land cover classes and water chemistry parameters for their predictive strength of macroinvertebrate diversity and biomass. We also matched prevailing macroinvertebrate life history traits with multiple time series of water chemistry data to further deduce the environmental conditions characterizing the biotic communities of each site. Our study aims to help each non-profit group prioritize conservation actions within their watersheds. Furthermore, we hope to provide a template for localized conservation assessment in an understudied region under mounting threat of degradation from hydraulic fracturing.

Assessing the Benefits of Forested Riparian Zones: A Qualitative Index of Riparian Integrity Is Positively Associated with Ecological Status in European Streams

Developing a general, predictive understanding of ecological systems requires knowing how much structural and functional relationships can cross scales and contexts. Here, we introduce the CROSSLINK project that investigates the role of forested riparian buffers in modified European landscapes by measuring a wide range of ecosystem attributes in stream-riparian networks. CROSSLINK involves replicated field measurements in four case-study basins with varying levels of human development: Norway (Oslo Fjord), Sweden (Lake Mälaren), Belgium (Zwalm River), and Romania (Argeş River). Nested within these case-study basins include multiple, independent stream-site pairs with a forested riparian buffer and unbuffered section located upstream, as well as headwater and downstream sites to show cumulative land-use impacts. CROSSLINK applies existing and bespoke methods to describe habitat conditions, biodiversity, and ecosystem functioning in aquatic and terrestrial habitats. Here, we summarize the approaches used, detail protocols in supplementary materials, and explain how data is applied in an optimization framework to better manage tradeoffs in multifunctional landscapes. We then present results demonstrating the range of riparian conditions present in our case-study basins and how these environmental states influence stream ecological integrity with the commonly used macroinvertebrate Average Score Per Taxon (ASPT) index. We demonstrate that a qualitative index of riparian integrity can be positively associated with stream ecological status. This introduction to the CROSSLINK project shows the potential for our replicated study with its panoply of ecosystem attributes to help guide management decisions regarding the use of forested riparian buffers in human-impacted landscapes. This knowledge is highly relevant in a time of rapid environmental change where freshwater biodiversity is increasingly under pressure from a range of human impacts that include habitat loss, pollution, and climate change.

Fertilization has negligible effects on nutrient export and stream biota in two North Florida forested watersheds

Managed pine forests cover nearly 130,000 km2 of the Southeastern U.S. and are important to the economic and ecological sustainability of the region. These stands are typically fertilized twice – at establishment and mid-rotation – to enhance timber production during a 25-year rotation. In Florida, Best Management Practices (BMPs) limit fertilizer application rates and require special management zones (SMZs) to reduce nutrient pollution. Recent adoption of numeric nutrient criteria (NNC) for streams and lakes in Florida has raised concerns that forest fertilization, even in compliance with BMPs, may result in excess nutrient loads and degrade stream ecological condition, particularly directly following fertilizer applications. We examined nutrient export dynamics and stream biota in two medium size watersheds (21 and 34 km2, respectively) dominated by loblolly pine (Pinus taeda) plantations in north Florida following fertilization. Over 54 months, we monitored stream discharge, nitrogen (TN, TKN, NO3-N, NH4-N), and phosphorus (TP, orthoP), as well as stream biota (benthic macroinvertebrates, phytoplankton chlorophyll a, periphyton and vascular plants) prior to and following watershed-scale fertilization. We condensed four years of scheduled fertilization into a single year, resulting in nutrient inputs substantially larger than typical. Because flow variation strongly controlled nutrient concentrations, we assessed pre- and post-fertilization concentration-discharge (C-Q) relationships, which remained unchanged. Annual mass export of N and P also remained unchanged, suggesting landscape retention of additional loads. Likewise, we observed no systematic change in biological indicators. These results suggest forest fertilization at BMP rates is unlikely to increase stream nutrient export, supporting the contention that fertilized pine forests in the southeastern coastal plain are protective of statewide goals for water quality and stream biotic integrity.

Invertebrate responses to land use in tropical streams: discrimination of impacts enhanced by analysis of discrete areas

We identified influences of land-use disturbances on invertebrate assemblages in streams draining eight areas of the Great Barrier Reef catchment in tropical Australia (~15.7–22°S), a region of high biodiversity. We used distance-based linear modelling (DistLM) to analyse assemblage data (103 taxa), richness and the SIGNAL2 taxon sensitivity index. DistLM of assemblages explained ~40% of variation across all samples and 7–54% of variation in individual areas. DistLM of richness and SIGNAL2 explained respectively 19–81 and 26–95% of variation. Explanatory variables were land use (especially cropping and grazing v. forest), riparian width, instream habitat, climate (drier south) and water quality (conductivity greater in south). Local impacts of activities such as mining were evident in models of individual areas. A detailed comparison of streams with contrasting riparian management demonstrated a 25% loss of richness, but no change in SIGNAL2 score. Accounting for local environmental gradients and using measures appropriate to the type of disturbance improved identification of impacts, and could form a framework for future regional monitoring of stream ecological condition. The impacts identified may be mitigated by remediation such as riparian rehabilitation, although management at catchment scales is required to be effective.

DNA metabarcoding from sample fixative as a quick and voucher-preserving biodiversity assessment method 1.

Metabarcoding is a powerful, increasingly popular tool for biodiversity assessment, but it still suffers from some drawbacks (specimen destruction, separation, and size sorting). In the present study, we tested a non-destructive protocol that excludes any sample sorting, where the ethanol used for sample preserving is filtered and DNA is extracted from the filter for subsequent DNA metabarcoding. When tested on macroinvertebrate mock communities, the method was widely successful but was unable to reliably detect mollusc taxa. Three different protocols (no treatment, shaking, and freezing) were successfully applied to increase DNA release to the fixative. The protocols resulted in similar success in taxa detection (6.8-7 taxa) but differences in read numbers assigned to taxa of interest (33.8%-93.7%). In comparison to conventional bulk sample metabarcoding of environmental samples, taxa with pronounced exoskeleton and small-bodied taxa were especially underrepresented in ethanol samples. For EPT (Ephemeroptera, Plecoptera, Trichoptera) taxa, which are important for determining stream ecological status, the methods detected 46 OTUs in common, with only 4 unique to the ethanol samples and 10 to the bulk samples. These results indicate that fixative-based metabarcoding is a non-destructive, time-saving alternative for biodiversity assessments focussing on taxa used for ecological status determination. However, for a comprehensive assessment on total invertebrate biodiversity, the method may not be sufficient, and conventional bulk sample metabarcoding should be applied.

Direct and indirect effects of multiple stressors on stream invertebrates across watershed, reach and site scales: A structural equation modelling better informing on hydromorphological impacts

The purpose of our approach was to take into account the nested spatial scales driving stream functioning in the description of pressures/ecological status links by analysing the results of a hierarchical model. The development of this model has allowed us to answer the following questions: Does the consideration of the indirect links between anthropogenic pressures and stream ecological status modify the hierarchy of pressure types impacting benthic invertebrates? Do the different nested scales play different roles in the anthropogenic pressures/ecological status relationship? Does this model lead to better understanding of the specific role of hydromorphology in the evaluation of stream ecological status?To achieve that goal, we used the Partial Least Square (PLS) path modelling method to develop a structural model linking variables describing (i) land use and hydromorphological alterations at the watershed scale, (ii) hydromorphological alterations at the reach scale, (iii) nutrients-organic matter contamination levels at the site scale, and (iv) substrate characteristics at the sampling site scale, to explain variation in values of a macroinvertebrate-based multimetric index: the French I2M2.We have highlighted the importance of land use effects exerted on both hydromorphological and chemical characteristics of streams observed at finer scales and their subsequent indirect impact on stream ecological status. Hydromorphological alterations have an effect on the substrate mosaic structure and on the concentrations of nutrients and organic matter at site scale. This result implies that stream hydromorphology can have a major indirect effect on macroinvertebrate assemblages and that the hierarchy of impacts of anthropogenic pressures on stream ecological status generally described in the literature - often determining strategic restoration priorities - has to be re-examined. Finally, the effects of nutrients and organic matter on macroinvertebrate assemblages are lower than expected when all the indirect effects of land use and hydromorphological alterations are taken into account.

Effects of conservation wetlands on stream habitat, water quality and fish communities in agricultural watersheds of the lower Mississippi River Basin

Wetland conservation programs (e.g., Wetland Reserve Program and Conservation Reserve Program) have been implemented throughout the Mississippi River Basin to reduce environmental impacts from agricultural activities. However, there is limited information on the overall effectiveness of these programs on improving stream ecological conditions. To address this issue, replicate streams from southeastern Arkansas draining watersheds containing predominately croplands (n=4, termed “cropland”) and created wetlands (n=4, termed “wetland”) were monitored monthly from August 2012 through July 2013. Although repeated-measures analyses of variance (ANOVA) detected many significant time×stream type interactions, several habitat parameters and total habitat scores exhibited a general improvement in wetland streams. Some water quality conditions were better in wetland streams (e.g., lower turbidity, total suspended solids, and nutrient) compared to cropland streams. The time (season) effect was significant (p<0.05) for 13 of the 14 water quality parameters measured, meaning that water quality varied seasonally. Among the water quality parameters measured, three (water temperature, pH, and turbidity) exhibited significant (p<0.05) time×stream type interaction, meaning that the stream type effect was not consistent through time (seasons). Fish community sampling collected 6543 specimens from 12 species during the study period; 4410 and 2133 fish specimens were collected from cropland and wetland streams, respectively. Fish community metrics such as species diversity, species evenness, and species richness index were not significantly (p>0.05) greater in wetland streams. Overall, the conservation wetlands in the Lower Mississippi River Basin appear to have significantly improved stream habitat and moderately improved water quality, though no significant fish community effect was detected.

Community-based monitoring of New Zealand stream macroinvertebrates: agreement between volunteer and professional assessments and performance of volunteer indices

ABSTRACTCommunity-based monitoring of freshwaters (a form of citizen science) is an area of growing interest globally. It could be used to augment professional monitoring in New Zealand, as is done in other countries, if the agreement between volunteer and professional assessments is close enough. We compared volunteer benthic macroinvertebrate data with professional data from parallel monitoring over 18 months at 8 sites across New Zealand. We found strong correlations (r=0.77–0.85) and little bias between volunteer data using volunteer indices and professional data using a professional index. Volunteer classifications in stream ‘quality classes' agreed with professional classifications in 70–85% of cases. Two volunteer-level biotic indices showed slightly different correlation and bias with respect to the professional biotic index. A modified volunteer index could blend the strengths of each. Presence-absence indices correlated as well as, or better than, their quantitative versions. We conclude that, given suitable training and support, volunteer assessments of stream ecological condition agree well with, and are only slightly more variable than, professional assessments.

Ecological status of streams in the area of the Vostochnyi Cosmodrome.

Ecological status of streams in the area of the Vostochnyi Cosmodrome.