Brownification or increasing water colour is a common problem in aquatic ecosystems. It affects both physico-chemical properties and biotic communities of the impacted waters. A common view is that ...lakes having low background water colour are most sensitive to brownification. In this article, we show that although low-colour and high-colour lakes respond differently to brownification, the effects on biotic communities can be strong irrespective of water colour. For phytoplankton production, the effect of brownification can be positive at low colour and negative at high colour, the relative effect being strongest at high colour. For fish foraging, the disturbance per increasing unit of colour may also be highest at high-colour conditions. Additionally, the presently used classification systems mostly describe the effects of eutrophication and do not account for the effects of brownification. Studies on the whole colour range of lakes are needed and indicators used in the ecological status assessment of lakes must be developed to reveal the effects of brownification. Indicators distinguishing the effects of brownification from those of eutrophication are especially needed.
Agriculture has been implicated in the loss of pristine conditions and ecology at river sites classified as at ‘high ecological status’ across Europe. Although the exact causes remain unclear, ...diffuse phosphorus (P) transfer warrants consideration because of its wider importance for the ecological quality of rivers. This study assessed the risk of P loss at field scale from farms under contrasting soil conditions within three case-study catchments upstream of near-pristine river sites. Data from 39 farms showed P surpluses were common on extensive farm enterprises despite a lower P requirement and level of intensity. At field scale, data from 520 fields showed that Histic topsoils with elevated organic matter contents had low P reserves due to poor sorption capacities, and received applications of P in excess of recommended rates. On this soil type 67% of fields recorded a field P surplus of between 1 and 31kgha−1, accounting for 46% of fields surveyed across 10 farms in a pressured high status catchment. A P risk assessment combined nutrient management, soil biogeochemical and hydrological data at field scale, across 3 catchments and the relative risks of P transfer were highest when fertilizer quantities that exceeded current recommendations on soils with a high risk of mobilization and high risk of transport as indicated by topographic wetness index values. This situation occurred on 21% of fields surveyed in the least intensively managed catchment with no on-farm nutrient management planning and soil testing. In contrast, the two intensively managed catchments presented a risk of P transfer in only 3% and 1% of fields surveyed across 29 farms. Future agri-environmental measures should be administered at field scale, not farm scale, and based on soil analysis that is inclusive of OM values on a field-by-field basis.
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•Farm and field phosphorus management was assessed in near-pristine river catchments.•Field P surpluses found mostly on soils with >20% organic matter and low P sorption•High risk areas were identified on farms with no nutrient management planning.•Extensive farmers should have greater access to nutrient management planning.•Nutrient management planning must incorporate soil conditions.
Environmental water quality monitoring aims to provide the data required for safeguarding the environment against adverse biological effects from multiple chemical contamination arising from ...anthropogenic diffuse emissions and point sources. Here, we integrate the experience of the international EU-funded project SOLUTIONS to shift the focus of water monitoring from a few legacy chemicals to complex chemical mixtures, and to identify relevant drivers of toxic effects. Monitoring serves a range of purposes, from control of chemical and ecological status compliance to safeguarding specific water uses, such as drinking water abstraction. Various water sampling techniques, chemical target, suspect and non-target analyses as well as an array of in vitro, in vivo and in situ bioanalytical methods were advanced to improve monitoring of water contamination. Major improvements for broader applicability include tailored sampling techniques, screening and identification techniques for a broader and more diverse set of chemicals, higher detection sensitivity, standardized protocols for chemical, toxicological, and ecological assessments combined with systematic evidence evaluation techniques. No single method or combination of methods is able to meet all divergent monitoring purposes. Current monitoring approaches tend to emphasize either targeted exposure or effect detection. Here, we argue that, irrespective of the specific purpose, assessment of monitoring results would benefit substantially from obtaining and linking information on the occurrence of both chemicals and potentially adverse biological effects. In this paper, we specify the information required to: (1) identify relevant contaminants, (2) assess the impact of contamination in aquatic ecosystems, or (3) quantify cause–effect relationships between contaminants and adverse effects. Specific strategies to link chemical and bioanalytical information are outlined for each of these distinct goals. These strategies have been developed and explored using case studies in the Danube and Rhine river basins as well as for rivers of the Iberian Peninsula. Current water quality assessment suffers from biases resulting from differences in approaches and associated uncertainty analyses. While exposure approaches tend to ignore data gaps (i.e., missing contaminants), effect-based approaches penalize data gaps with increased uncertainty factors. This integrated work suggests systematic ways to deal with mixture exposures and combined effects in a more balanced way, and thus provides guidance for future tailored environmental monitoring.
According to the Water Framework Directive (WFD), biological quality elements constitute the basis for assessing ecological status of surface
waters. Biological communities are good indicators of ...water quality because they reflect environmental conditions over time and do not require frequent sampling. The main aims were to assess trophic and ecological status of the Lake Visovac (Krka River hydrosystem, South Croatia) using phytoplankton together with supportive physico-chemical parameters, eutrophication status and impact indicators. We also tested the viability of Chlorophyll-a (Chl-a) and Hungarian Lake Phytoplankton Index (HLPI) as proposed metrics in the standard regulatory monitoring procedure. The phytoplankton samples, Chl-a and physical- chemical parameters were taken on a monthly basis from April to September in 2016
and 2019. In 2016, the most dominant species was Pantocsekiella ocellata (Pantocsek) K.T.Kiss & Ács, while in 2019 it was accompanied by Ceratium hirundinella (O.F.Müller) Dujardin. According to
Chl-a, Lake Visovac was within the limits of oligo- to mesotrophic status. Based on the HLPI index, the Lake ecological status was assessed
as Good. Chl-a showed a statistically significant positive correlation with temperature, while HLPI was positively correlated with oxygen and Secchi depth. We propose the use of Chl-a for rapid bioassessment on a weekly basis, whilst more complex HLPI index should be applied monthly. Further improving the confidence level of the metrics used to assess the
ecological status and a comprehensive revision of boundaries for included indicators is of fundamental importance.
• We review the methods for setting reference conditions and targets. • Some indices showing inability to detect human pressures are due to the use of inappropriate methods for setting reference ...conditions.
Assessing benthic quality status of marine and transitional water habitats requires to set up both: (i) tools (i.e. indices) to assess the relative quality of the considered habitat, and (ii) reference conditions for which such indices can be computed and used to infer the absolute ecological status (ES) of the considered habitat. The development of indices, their comparison and the assessment of the causes of their discrepancies have been largely discussed but less attention has been paid to the methods used for the setting of adequate reference conditions, although this step is clearly crucial for the sound assessment of ES. This contribution reviews the approaches available in setting both reference conditions (pristine areas, hindcasting, modelling and best professional judgment) and targets (baseline set in the past, current baseline and directional/trends). We scored the use of pristine or minimally impacted conditions as the best single method; however, the other methods were judged as adequate then combined with best professional judgment. The case of multivariate AMBI (AZTI's Marine Biotic Index) is used to highlight the importance of setting correct reference conditions. Hence, data from 29 references, including 14 countries from Europe and North America, and both coastal (15 cases) and transitional (17 cases) waters, have been used to study the response of multivariate AMBI to human pressures. Results show that the inability of this index to detect human pressure is in most cases linked with the use of inappropriate methods for setting reference conditions.
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•The WFD bioassessment scheme is highly valuable, but effectiveness can be improved.•Environmental Risk Assessment can inspire the improvement of WFD bioassessment.•Complementary ...approaches that provide added-value to bioassessment are identified.•A possible course of action towards improving the WFD bioassessment is proposed.•The proposal entails a tiered approach, includes ecotoxicology and expert judgement.
The EU Water Framework Directive (WFD) assessment scheme has been putting in force the evaluation of freshwater ecosystems in Europe, including a new paradigm of ecological status. After almost 20 years since the WFD implementation, it is imperative to evaluate the efficiency of its standard assessment scheme and to explore the possibility of learning how to improve its effectiveness. That is the spirit of this review, aiming (i) to explore the existing literature on the WFD bioassessment scheme for assessing freshwater ecosystem health, particularly in lotic ecosystems (where the WFD scheme is most consolidated); (ii) to document which paths are suggested by the scientific community to improve the efficiency of the bioassessment in tackling current challenges. In the specific arena of bioassessment, we first identify the major constraints to the WFD full implementation in rivers. Second, we analyse retrospective Ecological Risk Assessment (ERA) as an evaluation approach supporting management actions that could inspire improvements in the WFD bioassessment scheme. Third, we review the advances and debate on complementary metrics to improve WFD evaluation protocols and/or the feasibility of the evaluation outcome. Fourth, a conceptual scheme for an improved evaluation strategy is presented. Our proposal essentially merges the WFD bioassessment scheme with the ERA philosophy, proposing a tiered approach of increasing complexity and spatial resolution, where expert judgement is included surgically at all decision stages. This scheme requires true integration of chemical, ecological and ecotoxicological LoE for a quantitative estimation of risks, and provides a comprehensive framework that accommodates tools and perspectives already suggested by other authors. Besides providing a literature review on the strengths and weaknesses of the current WFD bioassessment scheme, we wish to open way for the scientific discussion towards an improved conceptual scheme for the evaluation of ecosystem health.
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•We harmonised nine macrophyte-based approaches for assessing lake ecological status.•We established relationships between the common view and nutrient concentrations.•Submerged ...vegetation decrease and free-floating plants increase along the status gradient.•We describe indicator taxa for ‘good’ and ‘less than good’ ecological status.•We establish a ‘guiding image’ of the macrophyte community at ‘good’ ecological status.
The European Water Framework Directive has been adopted by Member States to assess and manage the ecological integrity of surface waters. Specific challenges include harmonizing diverse assessment systems across Europe, linking ecological assessment to restoration measures and reaching a common view on ‘good’ ecological status.
In this study, nine national macrophyte-based approaches for assessing ecological status were compared and harmonized, using a large dataset of 539 European lakes. A macrophyte common metric, representing the average standardized view of each lake by all countries, was used to compare national methods. This was also shown to reflect the total phosphorus (r2 = 0.32), total nitrogen (r2 = 0.22) as well as chlorophyll-a (r2 = 0.35–0.38) gradients, providing a link between ecological data, stressors and management decisions. Despite differing assessment approaches and initial differences in classification, a consensus was reached on how type-specific macrophyte assemblages change across the ecological status gradient and where ecological status boundaries should lie.
A marked decline in submerged vegetation, especially Charophyta (characterizing ‘good’ status), and an increase in abundance of free-floating plants (characterizing ‘less than good’ status) were the most significant changes along the ecological status gradient. Macrophyte communities of ‘good’ status lakes were diverse with many charophytes and several Potamogeton species. A large number of taxa occurred across the entire gradient, but only a minority dominated at ‘less than good’ status, including filamentous algae, lemnids, nymphaeids, and several elodeids (e.g., Zannichellia palustris and Elodea nuttallii). Our findings establish a ‘guiding image’ of the macrophyte community at ‘good’ ecological status in hard-water lakes of the Central-Baltic region of Europe.
The overall vitality and quality of the coastline can be improved through ecological transformation; ecological status assessment can scientifically guide this modification by putting forward a ...transformation plan for the coastline. This study took the Shenzhen Bay area between Hong Kong and Shenzhen as the study area to build an index system and combined it with quantitative and qualitative methods by designing the code of data processing, calculation, and analysis through the MATLAB platform, with the goal being to put forward the directions and suggestions for coastline transformation based on the analysis of results. The results and conclusions are as follows: (1) The key aspects of the ecological transformation of the Shenzhen Bay Coastline are water quality, coastal wetland restoration, landscape diversity, beach stability, and infrastructure improvement. (2) Actions to promote these aspects include overall shoreline control of water pollution, cultural landscape implantations, the improvement of existing infrastructure, and the restoration of selected beach sand regions, mangrove wetlands, and eroded shorelines. Suggestion includes the critical support which comes from the public needs for information acquisition and science education, in addition with the policy and management, all should be formulated into the transformation plan. The index system can be applied to other regions at home and abroad, and the results and conclusions based on the index system could also provide criteria for planning the ecological transformation process.
•An index system about eco-status assessment was constructed.•Integrated design the code of data processing, calculation, and analysis.•Comprehensive analysis about orientations and suggestions on ecological transformation.
The intertidal wetland ecosystem is vulnerable to environmental and anthropogenic stressors. Understanding how the ecological statuses of intertidal wetlands respond to influencing factors is crucial ...for the management and protection of intertidal wetland ecosystems. In this study, the community characteristics of bacteria, archaea and microeukaryote from Jiangsu coast areas (JCA), the longest muddy intertidal wetlands in the world, were detected to develop a composite microbial index of biotic integrity (CM-IBI) and to explore the influence mechanisms of stresses on the intertidal wetland ecological status. A total of 12 bacterial, archaea and microeukaryotic metrics were determined by range, responsiveness and redundancy tests for the development of ba-IBI, ar-IBI and eu-IBI. The CM-IBI was further developed via three sub-IBIs with weight coefficients 0.40, 0.33 and 0.27, respectively. The CM-IBI (R2 = 0.58) exhibited the highest goodness of fit with the CEI, followed by ba-IBI (R2 = 0.36), ar-IBI (R2 = 0.25) and eu-IBI (R2 = 0.21). Redundancy and random forest analyses revealed inorganic nitrogen (inorgN), total phosphorus (TP) and total organic carbon (TOC) to be key environmental variables influencing community compositions. A conditional reasoning tree model indicated the close associating between the ecological status and eutrophication conditions. The majority of sites with water inorgN<0.67 mg/L exhibited good statuses, while the poor ecological status was observed for inorgN>0.67 mg/L and TP > 0.11 mg/L. Microbial networks demonstrated the interactions of microbial taxonomic units among three kingdoms decreases with the ecological degradation, suggesting a reduced reliability and stability of microbial communities. Multi-level path analysis revealed fishery aquaculture and industrial development as the dominant anthropogenic activities effecting the eutrophication and ecological degradation of the JCA tidal wetlands. This study developed an efficient ecological assessment method of tidal wetlands based on microbial communities, and determined the influence of human activities and eutrophication on ecological status, providing guidance for management standards and coastal development.
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•A composite microbial index of biotic integrity is developed in Jiangsu coast wetland.•The novel index is constructed from three different kingdoms of microbes.•Human activities and eutrophication are the reasons for ecological status decline.•A decision classification tree model is used to predict CM-IBI.•Eutrophication weakens interaction and stability of microbial communities.
Current approaches to measure ecosystem services (ES) within natural capital (NC) and nature-based solutions (NbS) assessments are generally coarse, often using a single figure for ecosystem services ...(e.g., nutrient remediation or blue carbon sequestration) applied to the local or national habitat stock, which fails to take account of local ecosystem conditions and regional variability. As such, there is a need for improved understanding of the link between habitat condition and ES provision, using comparable indicators in order to take more informed management decisions. Here the UK, Solent Marine Sites (SEMS) is used as a case study system to demonstrate how Water Framework Directive (WFD) ‘ecological status’ and other indicators of ecosystem condition (state or quality) can be coupled with habitat extent information to deliver a more precise locally-tailored NC approach for active coastal and marine habitat restoration. Habitat extent and condition data are collected for seven NbS relevant coastal habitats (littoral sediment, mat-forming green macroalgae, subtidal sediment, saltmarsh, seagrass, reedbeds and native oyster beds). The workflow includes: 1) biophysical assessment of regulatory ES; 2) monetary valuation; and 3) compilation of future scenarios of habitat restoration and creation. The results indicate that incorporating classifications by condition indices into local NC extent accounts improved ES benefits by 11–67%. This suggests that omitting condition from NC assessments could lead to undervaluation of ES benefits. Future scenarios of restoration in the SEMS also show that the additional regulatory benefits of reaching ‘Good’ ecological status are £376 million annually, but could be as much as £1.218 billion if ‘High‘status and all habitat creation targets were met. This evidence of the potential value of restoration and importance of including condition indices in assessments is highly relevant to consider when investing in water ecosystems conservation and restoration as called for by the UN Decade on Ecosystem Restoration (2021−2030), and more generally in global nutrient neutrality and blue carbon policy strategies.
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•Natural capital (NC) condition accounts are assessed using nature-based solution (NbS) scenarios.•Links between habitat condition (ecological status) and ecosystem services supply are explored.•Integrating habitat condition indices improved ecosystem service (ES) benefits by 11–67%.•Not including condition in NC or NbS assessments could lead to undervaluation of ES benefits.•Restoring existing and creating new NbS habitats in Solent could yield £1.218 billion per year.
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