Danube Floodplain Research Articles

Multilayer networks in landscape ecology: a case study to assess changes in aquatic habitat connectivity for flying and non-flying benthic macroinvertebrates in a Danube floodplain

ContextIn efforts to mitigate anthropogenic impacts on floodplain biodiversity, restoration measures that enhance habitat connectivity have been applied. However, these approaches have either neglected the spatial position of water bodies or the dynamic nature of the floodplain ecosystem.ObjectivesThis study focuses on the novel application of the multilayer network framework to assess changes in the aquatic habitat connectivity in floodplains, showcasing its application in the context of aquatic passive dispersal (drift) of two indicator groups of benthic macroinvertebrates (Oligochaetes and Chironomids)MethodsOur case study is located in the Donau-Auen National Park in Austria and follows floodplain restoration measures (side-channel reconnection) applied in the mid-1990s. Multilayer networks were constructed to represent the conditions before, short-term, and long-term after restoration to quantify habitat connectivity across inundation frequencies. Our network analyses involved multilayer correlation, static and dynamic monolayer centralities (centrality profiles), and multilayer centrality assessments. We used a Partial Least Squares Regression analysis as a variable selection tool to identify which centrality measures better explained the variance in α\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\alpha$$\\end{document} diversity and Local Contributions to Beta Diversity (LCBD) of benthic macroinvertebrates.ResultsIn the short-term, our connectivity analysis indicated an increase in habitat connectivity. However, centrality profiles, multilayer correlation, and multilayer centrality techniques identified a long-term decrease in connectivity. Multilayer centralities had higher Variable Importance in the Projection scores (VIP) than their monolayer counterpart in explaining variations in α\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\alpha$$\\end{document} diversity and LCBD for strict aquatic dispersers. Meanwhile, for flying dispersers, monolayer centralities had the highest VIP scores for explaining α\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\alpha$$\\end{document} diversity.ConclusionsThis study underscores the relevance of integrating dynamic aspects of water-mediated transport beyond traditional pairwise distances. Although in this study we apply this tool by showcasing the aquatic passive dispersal mode, the application of this method can be extended to other dispersal modes and representative abilities for diverse groups of aquatic organisms. The expanding cross-disciplinary applications and open-source tool development for multilayer networks offer practical implications for planning and evaluating management measures.

Floodplains as a Suitable Habitat for Freshwater Fish: The Length–Weight Relationships and Condition Factors of Fish Inhabiting a Danube Floodplain in Croatia

When studying the well-being and fitness of ichthyofauna in a specific area, vital information comes from length–weight relationships (LWRs) and condition factor analyses and calculations. Data were collected from 2015 to 2019 in an area important for fish shelter, feeding, and spawning. Twenty four species belonging to 10 different families were identified from the total 16,895 of caught individuals, with the most abundant species being Blicca bjoerkna. The calculation of LWRs was possible for 19 species, (R2 = 0.7049–0.9998 (p < 0.05)), with the values of the mean coefficient b ranging from 2.6831 to 3.5747, indicating an overall positive allometric growth in the fish population. The results of Fulton’s and the relative condition factors showed that a total of eight species were in a relatively good condition, although the species in question varied between the two condition factors. Fulton’s condition factor showed the highest average value for Lepomis gibbosus (1.4956), while Cobitis elongatoides had the lowest (0.4739). Contrarily, the relative condition factor showed the highest average value for Silurus glanis (1.0524), and the lowest for Gymnocephalus cernua (1.0023). The lower values of calculated condition factors in some species could be attributed to sampling being conducted during the colder months of autumn and winter. Future studies should include seasonal sampling in order to achieve a better understanding how various abiotic factors impact the condition factors of these fish species. Nevertheless, this research provided valuable data on the status of the fish population in the floodplain and could be used as a guideline for designing future ichthyofauna studies in this area.

Maintenance of High Phytoplankton Diversity in the Danubian Floodplain Lake over the Past Half-Century.

Riverine floodplains are recognized as centers of biodiversity, but due to intense anthropogenic pressures, many active floodplains have disappeared during the last century. This research focuses on the long-term changes in phytoplankton diversity in the floodplain lake situated in the Kopački Rit (Croatia), one of the largest conserved floodplains in the Middle Danube. The recent dataset from 2003 to 2016 and historical data from the 1970s and 1980s indicate high phytoplankton diversity, summarising 680 taxa for nearly half a century. The variability of species richness is driven by specific in-lake variables, particularly water temperature, water depth, total nitrogen, pH, and transparency, determined by a redundancy analysis of the current data. The high phytoplankton diversity levels are sustained regardless of intense pressures on the lake environment, including exposure to strong anthropogenic pollution in the past and extreme hydrological events, both droughts and floods, which have increasingly affected this part of the Danube in the last decades. The conserved hydrological connection between various biotopes along the river-floodplain gradient seems crucial in maintaining high phytoplankton diversity. Accordingly, conserving natural flooding is mandatory to maintain high biodiversity in complex and dynamic river-floodplain systems.

Brighteness-dependent visual attractiveness of the human body for horse flies (Diptera: Tabanidae): a field experiment.

The landing patterns of blood-sucking females (Diptera: Tabanidae) are largely influenced by their visual perceptions. When attacking humans, the shape of different body parts and overall brightness of the body could be the factors determining the place of blood-sucking. The visual attractiveness of the human body for tabanids was investigated through a black and a white mannequin in the Danube floodplain, Slovakia. The mannequins were covered by glue once a week. On both of the mannequins, 332 horse flies were stuck. The trapped horse flies on the mannequins belong to the genera Tabanus Linnaeus, 1758, Hybomitra Enderlein, 1922, Chrysops Meigen, 1803, Haematopota Linnaeus, 1758 and Atylotus (Linnaeus, 1767). Based on the trapped tabanids, the black mannequin is 6.06 times more attractive than the white one. The most tabanid carcasses were found on the lower limbs (56.32%) and the least occurred on the head (2.1%), the difference in their occurrence between the lower limbs and head of both mannequins was significant (P < 0.001). A similar significant difference was observed on certain parts of both mannequins on the taxonomical level of the genera Tabanus, Hybomitra, and Atylotus, the carcasses of which aggregated mostly on the lower limbs, rather than on the upper limbs and head.

Control of invasive Ailanthus altissima in the Danube floodplain forests in Bratislava using chemical and biological agents

Ailanthus altissima is an Asian tree species that has become invasive on all continents except Antarctica. In Europe, it frequently invades native floodplain forest habitats. Three methods of control are known presently, namely mechanical, chemical, and biological. As each method has its advantages and disadvantages, we compared chemical control using glyphosate with biological control using the Verticillium nonalfalfae isolate Vert56 in the protected area of the Danube floodplain forests belonging to the municipality of Bratislava, Slovakia. Furthermore, we modelled the potential distribution of A. altissima in Bratislava and searched for factors that influenced its distribution. Our results showed that although chemical control is more effective in inducing mortality of inoculated individuals, biological control additionally allows the elimination of individuals growing in the vicinity of inoculated individuals. Results also suggest that, in the situation where the Verticillium wilt becomes chronic, microclimatic conditions may play a significant role in biological control, as individuals growing in dry, sunny sites showed a higher percentage of mortality compared to individuals growing in moist, shaded forest sites. According to the species distribution model, A. altissima is equally likely to exist in urban areas and floodplain forests, as evidenced by the same probability of species occurrence. A. altissima is spreading into Bratislava´s floodplain forests, primarily around roads and railway tracks, but it also benefits from increased light conditions on forest regeneration sites caused by deforestation.

Slow ecology: Local knowledge and natural restoration on the lower Danube

In the first half of the 2000s, one project to restore the former Danube floodplain was carried out in Belene, a marginal town on the Bulgarian Danube. The aim of this article is to record the practices that were already in place before the interventions on the Danube, as part of a heterogeneous local knowledge that had an alternative vision to the scientific knowledge of experts involved in the restoration project. The data comes from qualitative interviews with locals and experts implicated in this project, as well as ethnographic observations from the fieldwork I carried out in 2013–2014, 2020 and 2022. The conclusion is that without attempting to replace the scientific knowledge, the locals aim to impose, through their local knowledge, a sort of slow ecology that eases the pace of the restoration of the former Danube floodplains.

Diptera species recorded for the first time in Slovakia found along the Danube floodplain

Four species of Diptera are recorded as new for the fauna of Slovakia: Acrocera orbiculus (Fabricius, 1787) (Acroceridae), Conops insignis Loew, 1848 (Conopidae), Hermetia illucens (Linnaeus, 1758) (Stratiomyidae), and Tolmerus cowini (Hobby, 1946) (Asilidae). The specimens were collected by means of Malaise trap, yellow pan trap, and sweep nets, in the years 2019&amp;ndash;2022. Our findings highlight the value of the Danube floodplain from a conservation point of view. The appearance of H. illucens in Bratislava fits well with what is known about this synanthropic species.

Biodiversity assessment of the Danube region as a tool for the development of protected areas in the region

The paper uses the method of geospatial biodiversity assessment in the Danube region based on an expert evaluation of the distribution of species richness of fish, amphibians, reptiles, birds and mammals. The 10-point grading scale was used to evaluate the number of species in 200 sample plots of the study region. Points from 1 to 10 were separately calculated for the species in each taxonomic group. The analysis showed a close relationship between the Lower Danube floodplain and the small steppe river basins, which together make up a single natural region. A practical testing of the geospatial assessment of the species richness was done for the first time in the Danube region. An important applied result of the research is the opportunity to assess missing elements in the environmental network of the region. This approach will justify the need to designate various types of protected areas, both at the national level (natural reserves) and at the international level (the Emerald network sites and wetlands). The areas could further be used to develop a unified ecological framework, thus contributing to the protection of rare and endangered species of the region.

Microscopic food webs under vanishing winters

Climate warming is affecting winter conditions in temperate regions, causing rapid changes in the formation and maintenance of snow and ice cover. However, little is known about planktonic and epixylon communities in dynamic river-floodplain systems in winter, as previous research has focused on the spring and summer „growing seasons“. Therefore, changes in the diversity, abundance, and functional groups of phytoplankton, zooplankton, and epixylon in the Danube floodplain (Kopački Rit Nature Park) were studied. In winter (January - March), water surfaces were covered only by a thin and patchy ice cover. Plankton and epixylon were diverse and abundant, and the changes in functional groups described the conditions prevailing in the studied waters well. The relatively stable conditions at the beginning of the study favoured the development of phytoplankton (diatoms, cryptophytes, ochrophytes), and epixylic taxa (diatoms, cyanobacteria) both belong to functional groups characteristic of shallow, turbid waters. Intense flooding and high grazing pressure reduced phytoplankton and epixylon abundance. The zooplankton community changed mainly due to the flood regime, subsequent nutrient loading, and food sources. Microfilter-feeding rotifers depended on phytoplankton, whereas microphytes that developed on epixylon were more important to the community for larger rotifers. The results suggest that further studies of floodplain winter communities are needed to understand better and predict floodplain ecology in future years.

Assessing Visitors’ Understanding of River National Park Functions and Landscapes

The assessment of visitor understanding and perceptions of natural landscapes and attitudes towards functions of a river national park is important for the acceptance and success of park management. The study asked 426 visitors to the Donau-Auen (Danube Floodplains) National Park in Eastern Austria about their affinity to the national park brand, their understanding of the river landscapes and attitudes towards the functions of a national park, and to what extent the visitors perceive the Danube Floodplains as a national park at all. The results show that a large proportion of respondents have some understanding of river national parks and their functions. Many respondents have a sense of being in a national park. However, for 60% of the respondents, the national park brand played almost no role in a visit to the national park. Visitors who have a higher affinity for the national park showed a stronger agreement with the functions of a national park. Those images from the Danube Floodplains National Park that depicted natural landscapes were judged by the majority of respondents to be typical of a river national park, but also meadows. Differences regarding the national park landscapes were not found among visitor affinity segments. Implications for environmental communication are presented.

A new insight into genetic structure of Danube and Italian foci of fascioloidosis

Human induced translocation and introduction of species have reshaped parasite fauna on a global scale. The introduction of the large American liver fluke Fascioloides magna from North America to Europe is an example of an invasive alien parasite causing significant ecological and economic damage. Recent genetic studies have shown that F. magna was introduced to Europe on multiple occasions forming three permanent foci of infection. This study primarily focuses on the poorly researched genetic structuring of F. magna flukes originating from Croatia and Serbia. Additional samples from USA and Italy are also included, thereby providing novel insights into F. magna’s biogeography. Partial cox1 and nad1 genes were amplified from 216 F. magna flukes extracted from red deer, roe deer, fallow deer, white-tailed deer and wild boar. Seven cox1 and nine nad1 haplotypes were identified, of which two cox1 and four nad1 haplotypes have not been not previously found. Our analysis has expanded the knowledge about possible sources of F. magna introduction to Europe, by identifying a cox1 haplotype shared by flukes from the north-eastern parts of the USA and Italy and another cox1 haplotype shared by flukes also from north eastern parts of the USA and the Danube floodplains.

Comparison of mitochondrial cox1 gene in Fascioloides magna from different host species

Large American liver fluke (Fascioloides magna) was introduced to Europe at least twice, via invaded North American deer species. These imports resulted in formation of three permanent foci of fascioloidosis - Italian, Czech and Danube floodplain forests. Molecular analysis revealed that flukes in Italian foci represent separate genetic group, and that flukes from Czech and Danube foci are genetically identical. Since previous studies of genetic structure of F. magna from Croatia were based on samples collected from red deer in one limited area (Baranja), the aim of this study was to analyse genetic diversity of 111 fluke samples collected from various hosts (red, roe and fallow deer, wild boar) and geographic locations in Croatia. On 355 base pair long cytochrome oxidase subunit 1 sequence, three haplotypes were identified - previously published CO1-Ha3 and CO1-Ha4, and one new haplotype named CO1-Ha36. Results obtained in our study confirmed as expected, that F. magna in Croatia has a Danube origin and that haplotypes are shared among different final host species.

Florix, an index to assess plant species in floodplains for nature conservation – Developed and tested along the river Danube

Natural floodplains are ecosystems with a diverse mosaic of habitats and site conditions, but also highly threatened due to anthropogenic pressures. Plant species occur in all habitat types and can indicate their value for nature conservation. To improve sustainable management of rivers and floodplains, several indices such as the River Ecosystem Service Index (RESI) have been developed. However, there are so far no assessment schemes for the entire range of floodplain plants. The common assessment approaches like biological integrity, achievement rates or threatened species (Red list), applying to other species groups or other ecosystems, are not appropriate in floodplains. Legal obligations and the need to restore floodplains clearly call for an index assessing the ecological value in a reference area which can be combined with a 5-scale assessment in accordance to established assessments like RESI or the Water Framework Directive.Five typical characteristics describing vascular plants’ adaptation to floodplain habitats were identified. These can be derived from published data sets available for all species in Germany. We checked these indicators for multicollinearity and selected three of them: species number, hydrodynamic indicators, nature conservation indicators. Species number highly correlate with habitat indicators and geographic occurrence. For the selected three indicators we determined thresholds to group habitats and their indicator rate to five classes (very low to very high value for nature conservation). These thresholds are valid for the river Danube and for the habitat types scrutinized in this study.The Florix approach was sensitive in data sets testing active against former floodplains and protected against unprotected areas: For the entire reference region ‘Danube floodplain’, Florix values were higher in the active floodplain and in the protected areas. Only the habitat type ‘water bodies’ showed better scores for habitats in the former floodplain, for ‘softwood forests’ the status of being part of a protected area had no effect. Florix results were validated in two case studies differing in land use intensity. The region with dominant agricultural use showed significantly lower values than that with a higher portion of forests and grasslands.Florix can be used for a floristic conservation status assessment at single habitat level or for the entity of a study region in comparison to a reference region. It allows to identify main pressures and to complement a habitat-type based evaluation. To achieve higher comparability, we should strive for a generalized monitoring in Europe like it is common in aquatic ecosystem monitoring.

How Can We Identify Active, Former, and Potential Floodplains? Methods and Lessons Learned from the Danube River

Floodplains are a fundamental source of multiple functions and services. Despite their various benefits, a dramatic reduction in floodplain areas has occurred in most large river systems over the last few centuries, and is still ongoing. Human modifications (such as river regulation, dam construction, and land use changes) due to economic growth, increasing population size, etc., were and still are drivers of major floodplain losses. Therefore, studies offering solutions for floodplain preservation and restoration are of great importance for sustainable floodplain management. This paper presents methods to identify active, former, and potential floodplains, and their application to the Danube River. We used hydraulic data, historical sources, and recent geospatial data to delineate the three floodplain types. Fifty hydraulically active floodplains larger than 500 ha were identified. According to our results, the extent of Danube floodplains has been reduced by around 79%. With the support of different representatives from the Danube countries, we identified 24 potential floodplains. However, the share of active and potential floodplains in relation to former floodplains ranges between 5% and 49%, demonstrating the huge potential for additional restoration sites. This analysis contributes to an understanding of the current and the past floodplain situation, increases awareness of the dramatic floodplain loss along the Danube, and serves as a basis for future floodplain management.

Holistic Approach for Estimating Water Quality Ecosystem Services of Danube Floodplains: Field Measures, Remote Sensing, and Machine Learning

Human pressure has caused river ecosystems to be severely damaged. To improve river ecosystems, “working with nature”, i.e., nature-based Solutions (NbS), should be supported. The purpose of this paper is to evaluate the effects of a specific NbS, i.e., floodplain restoration, which provides, among others, the ecosystem service of nutrient retention. For these, an in-depth time series analysis of different nutrients’ concentrations and water physiochemical parameters was performed to obtain Water Quality Indices (WQI), which were calculated along the river. To estimate water quality from remote sensing data and to generate water quality maps along the river, Sentinel-2 water products were validated against in situ data, and linear regression (LR), random forest (RF), and support vector regression (SVR) were trained with atmospherically corrected data for chlorophyll-a and TSM. The results show different outcomes in diverse floodplains in terms of improvement of the water quality downstream of the floodplains. RF demonstrated higher performance to model Chl-a, and LR demonstrated higher performance to model TSM. Based on this, we provide an insightful discussion about the benefits of NbS. These methodologies contribute to the evaluation of already existing NbS on the Danube River based on a quantitative analysis of the effects of floodplain ecosystems to water quality.

Diversity of Periphytic Chironomidae on Different Substrate Types in a Floodplain Aquatic Ecosystem

Different types of water bodies in lowland river floodplains represent vital biodiversity havens and encompass diverse microhabitats, which are essential for structuring different macroinvertebrate communities. Chironomidae larvae (Diptera) are an inseparable part of these communities, with their high richness and abundance. In three water body types within the Danube floodplain Kopački Rit in Croatia, over the course of four sampling campaigns, we recorded 51 chironomid taxa in periphyton on macrophytes, twigs, and glass slides. The most diverse were chironomid communities on macrophytes, whilst month-old periphyton on twigs supported the least taxa. Cricotopus gr. sylvestris, Dicrotendipes lobiger, Dicrotendipes spp., Endochironomus albipennis, Glyptotendipes pallens agg., Polypedilum sordens and Polypedilum spp. were present in all studied microhabitats. The type of substrate is a very important factor influencing Chironomidae diversity and abundance, which was evident in the presence and dominance of Corynoneura gr. scutellata and Monopelopia tenuicalcar in the dense macrophyte canopy epiphyton. Finding pristine floodplains such as Kopački Rit can be very challenging, as such areas are increasingly altered by human activities. Studies of resident species and the extent to which changes in the parent river influence floodplain communities are important for the protection and restoration of the floodplains.

Periphytic Ciliate Communities in Lake Ecosystem of Temperate Riverine Floodplain: Variability in Taxonomic and Functional Composition and Diversity with Seasons and Hydrological Changes

Periphytic ciliate communities of riverine floodplains have hardly been studied, although they play an important role in aquatic food webs and contribute to the overall ecosystem functioning. In this study we analyzed the taxonomic and functional composition and diversity of these communities across all seasons and hydrological phases. The study was conducted in a floodplain lake, a part of the large natural Danube floodplain, from February 2015 to September 2016. We found that higher temperature and hydrologically stable conditions during the lake isolation phase, when a high amount of suspended food is available, result in the highest ciliate abundances and dominance of relatively large suspension-feeding ciliates, mainly peritrichs, which could serve as good bioindicators for detecting disturbances in river-floodplain ecosystems. During the flow pulse phase, associated with lower temperatures, and during the phase of extreme floods, when the availability of suspended food was largely reduced, small surface-feeding ciliates prevailed in the periphyton. Further, while the total ciliate abundance was the lowest, the highest taxonomic and functional diversity was found, especially during an intermediate level of hydrological connectivity (flow pulse). Our results confirm the importance of different levels of hydrological connectivity for maintaining biodiversity in riverine floodplains and add to a growing awareness of the need to preserve the natural hydrological regimes of large rivers.

Geological and geomorphological conditions of Archar-Orsoya lowland as a factor for the formation of groundwater chemical composition and in risk of its contamination

The Archar-Orsoya lowland is situated in the Danube floodplain west of the town of Lom, NW Bulgaria. It is aligned in a west-east direction along the Danube River and to the south it is bounded by a high landslide slope, built of Pliocene clays and sands. Parallel to the shore, sand dunes are formed with lowered sections between them, in which there are conditions for swamping. The lowland is made up of the alluvial sediments of the Danube, represented by a lower gravelly-sandy layer and an upper sandy-clayey layer. In the gravelly-sandy layer unconfined groundwater is accumulated, with shallow water table – from 0.5 to 7 m beneath the surface. Groundwater is recharged by infiltration of precipitation, surface water and groundwater, which laterally flows into the alluvium from adjacent aquifers. At high waters, the Danube River suppresses the formed groundwater flow and temporarily feeds it. Due to the described formation conditions in the lowland, the chemical composition of groundwater is formed under the influence of intense dynamics and has a low TDS (total dissolved solids). The shallow groundwater table and the corresponding thin unsaturated zone are a prerequisite for easy groundwater contamination with components entering from the surface. Therefore, a map of depth to groundwater table is drawn to identify the most vulnerable areas.

Long-term deposition of fine sediments in Vienna's Danube floodplain before and after channelization

Investigations on the deposition processes in current alluvial landscapes are commonly affected by multiple forms of human interventions such as local hydraulic measures and reduced sediment transport caused by upstream reservoirs. The present study focuses on the sedimentation rates and floodplain accretion over 500 yr prior to major river engineering measures. A comprehensive borehole database and research on long-term fluvial dynamics in Vienna's Danube floodplain enabled us to correlate the thickness of fine sediment layers (silt and fine sand) with the morphological age of individual sites before the great regulation program 1870–1875. Five years after the onset of the sedimentation process on top of a gravel bar, the median deposition rate amounted to 18.60 cm yr−1. In the following decades the rate significantly decreased and leveled off after 300 yr with median annual rates between 0.15 and 0.10 cm. Five hundred years after the deposition process had started, the fine sediment layer reached a thickness of 2.64 m, of which half already had been deposited within the first 10 yr.Stabilization of riverbanks in 1870–1875 significantly boosted the long-term annual sedimentation rates by at least 23–41% (depending on the calculation method), although the volume of the suspended load decreased by 18–45% since around 1880. Assuming equal loads today would hypothetically yield a greater increase of the rates. As opposed to the historical situation featuring intensive lateral erosion, natural levee formation along the protected riverbanks has become a common phenomenon today. The thickness of fine sediment deposition and therefore the long-term “climax level” of the floodplain depends on numerous controlling factors including hydrological regime, sediment volume/size, stream power and riparian vegetation. Human interventions, i.e., bank stabilization, also alter the basic conditions for floodplain accretion, leading to greater sedimentation rates and higher floodplain levels.

Transformation of Danube Recreational Sites

The purpose of the research was to verify models of sustainable urbanization of the Danube riverside landscape in the suburban surroundings of Bratislava. The research focused on landscape-ecological forms of suburban urbanization in the contact of the river Danube, in the context of meanders of the Danube branches with the formation of recreational localities. The implementation of ecological principles was based on the concept of regional structures with a vision of the renewal of the ancient branches of the Danube for the creation of the climatic envelope of Bratislava from the southwestern side. The completion of the Petržalka, Slnečnice, Južné Mesto, and rural structures near Jarovce, Rusovce, and Čuňovo, conditioned by ecological urbanization, will acquire more landscape elements and a system of blue and green infrastructure. The hierarchical transition of the city to the suburban localities is solved by creating zones of recreation and sports on the Danube. Variant case studies of the "Danubia Park" near the village of Čuňovo are located on the southwestern bank of the Hrušov Reservoir of the Danube, with access to the Wild Water sports zone and the Danubiana Gallery complex. The research followed up on the verification of the recreational function in the landscape and focused on the level of low occupancy, the integration of sports and recreational functions, accessibility by all modes of transport, the penetration of recreation into the open landscape. For the identity of the original landscape, freely modeled connections to the riparian zone, work with water flow in the area, port, pedestrian and cycling connections to the EuroVelo route, outdoor museums of the Danube meadows, lakes and wetland communities, workouts, and multifunctional playgrounds, forms of wellness, sauna world and natural swimming. Ecological recreation concepts in the landscape of the Danube floodplains on the banks of the Danube used the modeling of banks, watercourse lines, meandering of recreational areas, green axes, play areas, elements, and zones. They used lighthouses and lookout towers for accent and orientation. The hierarchy of the release of small urban structures and loose forms of sensitive urbanization with functional flexibility and attractiveness proved the justification and location in the landscape of the Danube meadows, in the contact zones of the protected landscape and the watercourse. In this way, the importance of the suburban landscape structure is beneficial for the city not only in terms of functional attractiveness but also in terms of landscape protection and the climatic influence of the city's hinterland on its compact structures.