European Regional Centre for Ecohydrology

In this paper, we reflect on the implications for science, policy and practice of the recently introduced concept of Nature-Based Solutions (NBS), with a focus on the European context. First, we analyse NBS in relation to similar concepts, and reflect on its relationship to sustainability as an overarching framework. From this, we derive a set of questions to be addressed and propose a general framework for how these might be addressed in NBS projects by funders, researchers, policy-makers and practitioners. We conclude that: NBS need to be developed and discussed in relation to existing concepts to clarify their added value; When considering and implementing NBS, the ‘relabelling’ of related concepts and the misuse of the concept have to be prevented in order to avoid misunderstanding, duplication and unintended consequences; NBS as currently framed by the European Commission provides an opportunity for: a) transdisciplinary research into the design and implementation of solutions based on nature; and b) overcoming a bias towards development alternatives with narrow perspectives that focus on short-term economic gains and effectiveness; The strength of the NBS concept is its integrative, systemic approach which prevents it from becoming just another “green communication tool” that provides justification for a classical model of natural resource exploitation and management measures. To realise their full potential, NBS must be developed by including the experience of all relevant stakeholders such that ‘solutions’ contribute to achieving all dimensions of sustainability. As NBS are developed, we must also moderate the expectations placed on them since the precedent provided by other initiatives whose aim was to manage nature sustainably demonstrates that we should not expect NBS to be cheap and easy, at least not in the short-term.

The release of antibiotics to the environment, and the consequences of the presence of persistent antimicrobial residues in ecosystems, have been the subject of numerous studies in all parts of the world. The overuse and misuse of antibiotics is a common global phenomenon, which substantially increases the levels of antibiotics in the environment and the rates of their spread. Today, it can be said with certainty that the mass production and use of antibiotics for purposes other than medical treatment has an impact on both the environment and human health. This review aims to track the pathways of the environmental distribution of antimicrobials and identify the biological effects of their subinhibitory concentration in different environmental compartments; it also assesses the associated public health risk and government policy interventions needed to ensure the effectiveness of existing antimicrobials. The recent surge in interest in this issue has been driven by the dramatic increase in the number of infections caused by drug-resistant bacteria worldwide. Our study is in line with the global One Health approach.

Rivers support some of Earth’s richest biodiversity1 and provide essential ecosystem services to society2, but they are often fragmented by barriers to free flow3. In Europe, attempts to quantify river connectivity have been hampered by the absence of a harmonized barrier database. Here we show that there are at least 1.2 million instream barriers in 36 European countries (with a mean density of 0.74 barriers per kilometre), 68 per cent of which are structures less than two metres in height that are often overlooked. Standardized walkover surveys along 2,715 kilometres of stream length for 147 rivers indicate that existing records underestimate barrier numbers by about 61 per cent. The highest barrier densities occur in the heavily modified rivers of central Europe and the lowest barrier densities occur in the most remote, sparsely populated alpine areas. Across Europe, the main predictors of barrier density are agricultural pressure, density of river-road crossings, extent of surface water and elevation. Relatively unfragmented rivers are still found in the Balkans, the Baltic states and parts of Scandinavia and southern Europe, but these require urgent protection from proposed dam developments. Our findings could inform the implementation of the EU Biodiversity Strategy, which aims to reconnect 25,000 kilometres of Europe’s rivers by 2030, but achieving this will require a paradigm shift in river restoration that recognizes the widespread impacts caused by small barriers. Validated barrier inventories and modelling indicate that Europe’s rivers are fragmented by more than one million barriers, such as dams, weirs and fords, causing major impacts on biodiversity.

Insight into how environmental change determines the production and distribution of cyanobacterial toxins is necessary for risk assessment. Management guidelines currently focus on hepatotoxins (microcystins). Increasing attention is given to other classes, such as neurotoxins (e.g., anatoxin-a) and cytotoxins (e.g., cylindrospermopsin) due to their potency. Most studies examine the relationship between individual toxin variants and environmental factors, such as nutrients, temperature and light. In summer 2015, we collected samples across Europe to investigate the effect of nutrient and temperature gradients on the variability of toxin production at a continental scale. Direct and indirect effects of temperature were the main drivers of the spatial distribution in the toxins produced by the cyanobacterial community, the toxin concentrations and toxin quota. Generalized linear models showed that a Toxin Diversity Index (TDI) increased with latitude, while it decreased with water stability. Increases in TDI were explained through a significant increase in toxin variants such as MC-YR, anatoxin and cylindrospermopsin, accompanied by a decreasing presence of MC-LR. While global warming continues, the direct and indirect effects of increased lake temperatures will drive changes in the distribution of cyanobacterial toxins in Europe, potentially promoting selection of a few highly toxic species or strains.

Abstract To determine the drivers of phytoplankton biomass, we collected standardized morphometric, physical, and biological data in 230 lakes across the Mediterranean, Continental, and Boreal climatic zones of the European continent. Multilinear regression models tested on this snapshot of mostly eutrophic lakes (median total phosphorus [TP] = 0.06 and total nitrogen [TN] = 0.7 mg L −1 ), and its subsets (2 depth types and 3 climatic zones), show that light climate and stratification strength were the most significant explanatory variables for chlorophyll a (Chl a ) variance. TN was a significant predictor for phytoplankton biomass for shallow and continental lakes, while TP never appeared as an explanatory variable, suggesting that under high TP, light, which partially controls stratification strength, becomes limiting for phytoplankton development. Mediterranean lakes were the warmest yet most weakly stratified and had significantly less Chl a than Boreal lakes, where the temperature anomaly from the long‐term average, during a summer heatwave was the highest (+4°C) and showed a significant, exponential relationship with stratification strength. This European survey represents a summer snapshot of phytoplankton biomass and its drivers, and lends support that light and stratification metrics, which are both affected by climate change, are better predictors for phytoplankton biomass in nutrient‐rich lakes than nutrient concentrations and surface temperature.

In the context of global environmental and social change, with increasing pollution and decline of biodiversity of terrestrial and aquatic ecosystems having its deep roots in drastic modifications to hydrological mesocycles, there is an urgent need for a new approach for sustainability. The two often contradicting approaches to water resources management, i.e., (1) hydrotechnical, and (2) ecological, can be reconciled within the context of ecohydrology (EH). It seeks for the understanding of the underlying water-biota interactions as well as providing a new tool for management of water resources. While the majority of changes are nonreversible in the framework of ecohydrology it is possible to regulate (dual regulation) the processes, especially in novel ecosystems, as an alternative to conservation and restoration measures, in order to increase their carrying capacity in the four dimensions, as follows: (1) water resources, (2) biodiversity, (3) ecosystem services, and (4) resilience. The proposed approach aims to initiate a discussion and joint efforts of hydrological engineers, hydrologists, and ecologists towards formulation of the comprehensive strategy and scientific background for harmonization of society needs with the enhanced ecosystem potential. It stipulates for a change in paradigm not only in the environmental sciences but also in the global economy, engineering, and education systems.

Although it is not possible to completely eliminate flooding in an era of climate change and intensification of extreme weather events, effective flood prevention and management in river floodplains may make a significant contribution. The land use characteristics of a catchment and river valley determine, to a great extent, the functioning of a river floodplain, as well as the quantity and size of the flood pulses in the river. The paper is focused on the role played by ecohydrology in flood risk management and water quality. From the ecohydrological perspective, river floodplains are extremely important and capacious ecosystems which, being periodically flooded, absorb flood and pollutant peaks and may minimise the danger of flooding. Increased natural water retention capacity in floodplain areas and the whole basin in the face of progressive climate change is possible through three routes: the modelling of the hydrological budget of the catchment towards the sustainable ecohydrological management of floodplains, the optimal use of existing hydrotechnical infrastructure and the implementation of ecohydrological biotechnologies. Furthermore, with such a holistic perspective, the role of river floodplains is one that also enhances the resilience of the river basin against climate and anthropogenic change, as well as increasing flood safety, improving water quality and increasing its ecosystem services for society.

Cyanobacterial blooms in drinking water reservoirs may cause a variety of water quality problems, including those of taste and odor, and can compromise the water supply destined for human consumption. In response to this problem an online monitoring tool for analyzing the cyanobacterial concentration in intake water is of practical value. This study demonstrated a positive correlation between phycocyanin fluorescence and cyanobacterial biomass during Microcystis aeruginosa blooms in a lowland drinking water reservoir, using online detection. The highest correlation coefficients were found for a cyanobacterial biomass concentration below 15 mg freshweight/L, indicating that this method can be an effective early warning system. Rapid changes in fluorescence were observed when wind drift moved higher cyanobacterial concentrations into the water intake, indicating that fluorescence could be employed as a quick warning for changed requirements for plant operations.

Plastics have recently become an indispensable part of everyone's daily life due to their versatility, durability, light weight, and low production costs. The increasing production and use of plastics poses great environmental problems due to their incomplete utilization, a very long period of biodegradation, and a negative impact on living organisms. Decomposing plastics lead to the formation of microplastics, which accumulate in the environment and living organisms, becoming part of the food chain. The contamination of soils and water with poly(vinyl chloride) (PVC) seriously threatens ecosystems around the world. Their durability and low weight make microplastic particles easily transported through water or air, ending up in the soil. Thus, the problem of microplastic pollution affects the entire ecosystem. Since microplastics are commonly found in both drinking and bottled water, humans are also exposed to their harmful effects. Because of existing risks associated with the PVC microplastic contamination of the ecosystem, intensive research is underway to develop methods to clean and remove it from the environment. The pollution of the environment with plastic, and especially microplastic, results in the reduction of both water and soil resources used for agricultural and utility purposes. This review provides an overview of PVC's environmental impact and its disposal options.

The cyanobacterial cytotoxin cylindrospermopsin (CYN) has become increasingly common in fresh waters worldwide. It was originally isolated from Cylindrospermopsis raciborskii in Australia; however, in European waters, its occurrence is associated with other cyanobacterial species belonging to the genera Aphanizomenon and Anabaena. Moreover, cylindrospermopsin-producing strains of widely distributed C. raciborskii have not yet been observed in European waters. The aims of this work were to assess the occurrence of CYN in lakes of western Poland and to identify the CYN producers. The ELISA tests, high-performance liquid chromatography (HPLC)-DAD, and HPLC-mass spectrometry (MS)/MS were conducted to assess the occurrence of CYN in 36 lakes. The cyrJ, cyrA, and pks genes were amplified to identify toxigenic genotypes of cyanobacteria that are capable of producing CYN. The toxicity and toxigenicity of the C. raciborskii and Aphanizomenon gracile strains isolated from the studied lakes were examined. Overall, CYN was detected in 13 lakes using HPLC-MS/MS, and its concentrations varied from trace levels to 3.0 μg L(-1). CYN was widely observed in lakes of western Poland during the whole summer under different environmental conditions. Mineral forms of nutrients and temperature were related to CYN production. The molecular studies confirmed the presence of toxigenic cyanobacterial populations in all of the samples where CYN was detected. The toxicity and toxigenicity analyses of isolated cyanobacteria strains revealed that A. gracile was the major producer of CYN.

One of the greatest challenges facing global environmental science is the protection of aquatic from heavy metal contamination stemming from human activities. This article is intended as a response to the global dynamic evolution of industries, transportation, increased extraction of fossil fuels, ever-rising consumption patterns, and unregulated discharge of wastewater resulting in increasing of environmental pollution with heavy metals. The aim of the article extends beyond the mere identification of heavy metals in the environment; it encompasses a comprehensive analysis of their modes of transportation and fate, a thorough evaluation of their impacts on various trophic levels, and an in-depth exploration of their potential toxicity. Furthermore, this article looks toward a fresh era in environmental stewardship, characterized by a deep-seated commitment to improving the removal of such damaging pollutants from our environment. To continue to foster ecological and economic sustainability, as set out in the Sustainable Development Goals 2015, and develop global environmental policy, there is an increasing need for pioneering and comprehensive methods of environmental reclamation aimed at eradicating heavy metals from surface waters. Such comprehensive methods include ecohydrological biotechnologies and Nature-Based Solutions (NBS) based on knowledge of geochemical and molecular processes. Both are presented in this article under the global principle of 'One Health' - the health of the environment, people and animals. Due to its extensive effects on ecosystems, and the resulting need for international cooperation, it is crucial that the problem of heavy metal contamination is addressed on the global scale.

A large diversity of cyanobacteria is associated with the production of cyanotoxins. Appendix 2 reports an updated list of cyanobacterial species or genera: (i) producing toxin from isolated strains or (ii) suspected to produce toxins, based on data obtained from environmental samples (Table Appendix.1). The original species names assigned (or successively modified) by the indicated authors have been updated following the more recent changes in the taxonomic literature. A selected list of papers describing the presence of different cyanotoxins measured in samples containing cyanobacterial assemblages was also listed (Table Appendix.2).

Biological invasions have attracted particular attention since they often result in serious consequences for natural ecosystems. One planktonic invasive species is Cylindrospermopsis raciborskii, a cyanobacterium originally reported to occur exclusively in the tropics. Over the last few decades its range has extended to temperate regions and it occupies shallow highly eutrophic lakes previously dominated by other cyanobacteria. The purpose of this study was to examine the ecology of C. raciborskii during Planktothrix agardhii blooms in two shallow lakes in western Poland and to determine whether these species have different environmental preferences. Multiple linear regression showed that the biomass of P. agardhii was significantly negatively related to Secchi depth in Lake Bnińskie. In Lake Bytyńskie, P. agardhii was significantly positively related to concentrations of , chlorophyll a and total phosphorus and negatively related to Secchi depth, , and total nitrogen. Cylindrospermopsis raciborskii was significantly positively related only to concentrations of . There was a negative correlation between the biomass of P. agardhii and C. raciborskii perhaps showing different responses to environmental variables. Moreover, the biomass of P. agardhii was negatively correlated with Shannon–Wiener diversity of the phytoplankton assemblages. Our results support the concept that these cyanobacterial species have different environmental preferences and their niches differ from each other. These results suggest that light is an important driver of phytoplankton community structure resulting in shifts from a community dominated by P. agardhii in very turbid waters to more diverse communities perhaps including the invasive C. raciborskii in clearer waters.

Abstract Nature‐based solutions for water‐resource challenges require advances in the science of ecohydrology. Current understanding is limited by a shortage of observations and theories that can further our capability to synthesize complex processes across scales ranging from submillimetres to tens of kilometres. Recent developments in environmental sensing, data, and modelling have the potential to drive rapid improvements in ecohydrological understanding. After briefly reviewing advances in sensor technologies, this paper highlights how improved measurements and modelling can be applied to enhance understanding of the following ecohydrological examples: interception and canopy processes, root uptake and critical zone processes, and up‐scaled effects of land use on streamflow. Novel and improved sensors will enable new questions and experiments, while machine learning and empirical methods provide additional opportunities to advance science. The synergy resulting from the convergence of these parallel developments will provide new insight into ecohydrological processes and thereby help identify nature‐based solutions to address water‐resource challenges in the 21st century.

Research into artificial reproduction of chub was studied during three subsequent reproductive seasons. Chub reproduction was conducted in two different variations. In the first experiment different hormonal agents were given to fish, such as CPE, hCG, or an analogue of GnRH with dopamine antagonist (ovopel). In the second one, the optimum moment of applying of artificial reproduction was sought and the fish were only obtained an analogue of GnRH in different periods. The results obtained in two first seasons indicated that ovopel is the most effective agent for the artificial reproduction of chub. Consequently, it was decided that the fish would obtain only this agent in the final year of research. In last year (experiment II), chub spawners were taken to the hatchery under controlled conditions every few weeks from February to the beginning of June. Periodically, the maturity of oocytes was checked. As soon as the oocytes had achieved stage 2–3 of maturity, fish were obtained ovopel. It was noted that there was no problem with collecting semen. Obtaining oocytes was much more difficult. Most frequently, they were not obtained at all or obtained in very small amounts. It was also observed that the administration of hormones caused a very quick maturation of gonads and their over-maturation.

Comment - No abstract available.

The multiple positive effects of an active school commute have convinced many cities to promote home-school walks among children and increase the awareness of designing healthy, child-friendly routes. One of the ways to ensure a child-friendly and healthy daily walk to school is to increase the greenery that children encounter on their way. This paper aims to evaluate welfare-related disparities among children in the visibility of greenery along their home-school routes and link them with distributive (in)justice regarding aesthetic appreciation. We hypothesise that children who belong to poor welfare-related status group have lower visibility of greenery along their routes to school than other children. Furthermore, we hypothesise that aesthetic appreciation provided by the greenery surrounding home-school routes is not equitably distributed to all children. For this purpose, we conducted a visibility analysis for primary school pupils in Lodz (Poland). In particular, we quantified the amount of greenery in the visibility areas of 5, 10, 30 and 50 m along the home-school routes of children. Our results show that the median visibility of greenery along the home-school routes is lower for shorter visibility distances (5 and 10 m) and street trees, dense tree and shrub canopies what could be further related to limited aesthetic experiences. We found that children who belong to poor welfare-related status group have less greenery along their home-school routes than others. This could indicate a distributive environmental injustice may occur not only in terms of the availability of green spaces for inhabitant’s homes but also reveal disparities in the visibility of greenery during daily commutes. Our findings contribute to the ongoing discussion on making cities greener. In particular, they may be used by urban planners to identify priority streets for implementing urban green initiatives.

Under ongoing climate change and increasing anthropogenic activity, which continuously challenge ecosystem resilience, an in-depth understanding of ecological processes is urgently needed. Lakes, as providers of numerous ecosystem services, face multiple stressors that threaten their functioning. Harmful cyanobacterial blooms are a persistent problem resulting from nutrient pollution and climate-change induced stressors, like poor transparency, increased water temperature and enhanced stratification. Consistency in data collection and analysis methods is necessary to achieve fully comparable datasets and for statistical validity, avoiding issues linked to disparate data sources. The European Multi Lake Survey (EMLS) in summer 2015 was an initiative among scientists from 27 countries to collect and analyse lake physical, chemical and biological variables in a fully standardized manner. This database includes in-situ lake variables along with nutrient, pigment and cyanotoxin data of 369 lakes in Europe, which were centrally analysed in dedicated laboratories. Publishing the EMLS methods and dataset might inspire similar initiatives to study across large geographic areas that will contribute to better understanding lake responses in a changing environment.

In mid-July and August 2003 and 2004, 18 reservoirs in the Czech Republic were sampled for phytoplankton species composition and concentration of intracellular microcystins (MCs). As a consequence of high nutrient loading, most of the reservoirs experienced cyanobacterial blooms of various intensities, with the prevalence of cyanobacteria increasing markedly in August, along with a conspicuous shift in species composition toward dominance of Microcystis spp. Microcystins were detected in 90% of the samples, and their amount also increased considerably in August, reflecting the cyanobacterial biomass. In Microcystis-dominated samples, a significantly higher amount of MCs (p < 0.001) occurred than in samples in which other taxa prevailed. Microcystins were positively correlated with chlorophyll a and cyanobacterial biovolume (p < 0.05, R2 = 0.61 and 0.66, respectively), with the strongest correlation found for Microcystis spp. biovolume (p < 0.001, R2 = 0.87). This taxon was the most important producer of MCs in Czech reservoirs. The main structural variants of MCs were MC-LR, MC-RR, and MC-YR. This study's data also indicate that the relative share of MC variants (MC-LR and MC-RR) varies considerably with time, most likely as a consequence of different species and strain compositions during the summer. This study clearly demonstrates a high prevalence of MC-producing cyanobacteria in Czech reservoirs. Therefore, regular monitoring of these reservoirs is highly desirable in an effort to minimize potential health risks to the human population.

The aim of this study was early genetic identification of microcystin-producing cyanobacteria and monitoring their toxigenicity by determining toxin concentrations in three Polish lakes throughout the summer of 2004. The assessment of cyanobacterial blooms was carried out in shallow, eutrophic water bodies: Lake Jeziorak, Lake Bninskie, and Sulejow Reservoir. Samples for DNA, phycological, and toxin analyses were collected from July till October. Molecular analysis of the 16S rRNA region was used to detect cyanobacteria in water samples. The microscopic analysis was performed to investigate seasonal variation of phytoplankton. Cyanobacteria, with domination by Microcystis, Planktothrix, and Planktolyngbya were detected during the whole monitoring period in Sulejow Reservoir, Lake Bninskie, and Lake Jeziorak, respectively. The presence and identification of toxic strains in water bodies was studied by PCR amplification of mcy genes in the microcystis synthesis pathway. The presence of the mcyA, mcyB, mcyD, and mcyE genes in water samples indicated the genetic potential to produce microcystins. Toxicity of water samples and microcystin concentrations were established by PPIA and HPLC, respectively. The maximum concentration of microcystins was 11.13 microg/L and 4.67 microg/L in samples dominated by P. agardhii and M. aeruginosa, respectively. Molecular analysis showed that toxigenic strains of cyanobacteria occurred in the three lakes throughout the summer season.