Special sessions

SP 01: River rehabilitation and floodplain restoration: methods and measures for sustainable success

Convenors: Bernd Cyffka (CU Eichstaett-Ingolstadt/Floodplain Institute Neuburg, Germany), Ian Fuller (Massey University, New Zealand)

Worldwide, rivers and floodplains have been changed to suit human society. Often rivers were regarded as conduits for water, and managers ignored river morphology, sediment transport and other aspects of this complex ecosystem. Today we try to rehabilitate rivers and restore floodplains. But to what? And are we restoring resilient ecosystems? What methods and measures are necessary to turn back time, and is that even possible? There are only a few promising examples of genuine restoration in the world, but many unresolved cases and problems. In some major rivers like the Danube in Europe, the EU has tried to regulate issues by the Water Framework Directive, but other parts of the world (e.g. New Zealand) lack such targeted legislation. The session aims at presenting modern examples of river and floodplain restoration, and invites contributions representing both successes and failures, from which we will identify the key requirements for sustainable success.

SP 02: Fish Ecology in Rivers: ecosystem functions and impacts

Convenors: Hubert Keckeis (Univ. Vienna, Austria), Paul Humphries (Charles Sturt University, Australia)

Fish assemblages are strongly affected by human alterations and water extraction from rivers. In this session the underlying mechanisms associated with anthropogenic alteration to river ecosystems and how they affect assemblage structure and biodiversity of riverine fish communities will be considered. Topics can include bottom-up and top-down control, food web analyses and trophic relationships, productivity and production, resource partitioning, abiotic conditions and biotic interactions. We would like to explore our knowledge of which ecosystem functions and processes drive the occurrence, abundance and spatio-temporal distribution patterns of riverine fishes.

SP 03: Freshwater biodiversity: networks, monitoring, data compilation and publishing

Convenors: Astrid Schmidt-Kloiber (Boku Vienna, Austria), Sonja Jähnig (IGB Berlin, Germany), Aaike De Wever (INBO, Belgium), Koen Martens (RBINS, Belgium), Daniel Hering (UDE, Germany)

Global pressures on freshwater ecosystems are high and rising. Viewed primarily as a resource for humans, current land use and water management practice have led to catastrophic declines in freshwater species and the degradation of freshwater ecosystems, including rivers and floodplains. It is essential to close existing knowledge gaps like the distribution and status of freshwater biodiversity at all spatial and temporal scales as well as the question which data are needed to balance human needs while sustaining biodiversity. Recently formed multidisciplinary freshwater networks as the Alliance for Freshwater Life or Freshwater BON are intended to mobilize knowledge and data, to harmonise monitoring and to foster outreach and funding. We welcome contributions from all freshwater research networks as well as individually working scientists in the field of freshwater biodiversity, monitoring, data mobilisation, compilation and publishing.

SP04: The environmental flow and water management nexus: implementation challenges, strategies, and outcomes of environmental flow programs

Convenors: Sarah Yarnell (University of California Davis, USA), Robert Lusardi (University of California Davis, USA)

Integrating environmental flows in water management decision-making is critical to sustaining at-risk freshwater ecosystems. New modeling tools and frameworks for managing environmental water are emerging to address this need within distinct scientific, legal, social, and management contexts. The success of environmental flow programs depends on our understanding of ecosystem processes, how such understanding is expressed in modeling tools, and how environmental water needs are integrated in existing management frameworks. This session will highlight successes and challenges associated with the implementation of environmental flow programs from around the world. Talks will include: technical approaches that advance scientific understanding of river functioning; the development, implementation, and transferability of decision-support tools to guide management; examples of interdisciplinary collaboration and stakeholder engagement; and approaches for monitoring program effectiveness.

SP05: Role of aquatic plants in river biogeochemistry from source to mouth

Convenors: Jonas Schoelynck (University of Antwerp, Belgium), Stefan Preiner (BOKU Vienna, Austria)

Output of organic matter and inorganic nutrients from rivers have impacted the trophic state of the estuarine and coastal sea ecosystems globally. The quality and quantity of the nutrient loading is determined by upstream processes in the river basin. Not only because here a substantial part of the input takes place, but also because geomorphological, hydraulic, geochemical and ecological processes lead to retention, transformation or removal of materials. In-stream macrophytes are playing an important role in organic matter production and nutrient cycling though they have obtained less attention in literature. This session focusses on plant scale, patch scale, and reach scale effects of macrophytes on carbon and nutrient cycling. Research on direct impacts like metabolism and nutrient uptake studies, as well as on indirect effects considering macrophytes as ecosystem engineers, which controls flow and sedimentation are included.

SP06: Riverine landscapes under pressure - how much complexity is needed to perform integrative research?

Convenors: Bernhard Pucher (BOKU Vienna, Austria), Lena Simperler (BOKU Vienna, Austria), Matthias Pucher (BOKU Vienna, Austria), Peter Flödl (BOKU Vienna, Austria), Thomas Hein (BOKU Vienna, Austria)

Riverine landscapes are complex systems providing a variety of ecosystem services. Among others, pressures from land use change, energy procurement and urbanisation lead to heavily modified systems. To address drivers of change within socio-ecological systems at different spatial and/or temporal scales integrative approaches are necessary. This can open up methodological “black boxes” between different disciplines and thereby lead to a deeper understanding of the tight, but complex interactions between society and environment. Integrating more disciplines however leads to higher complexity (e.g. concepts, methods), raising the question of the optimal degree of complexity. In this interactive session, the approaches to integrative research and its implications on society and environment, policies and management options of riverine landscapes shall be discussed by oral and poster presentations.

SP07: Ecosystem services along rivers and floodplains – an integrative tool to assess and optimize river and floodplain management

Convenors: Barbara Stammel (KU Eichstaett-Ingolstadt, Floodplain Institute Neuburg, Germany), Mathias Scholz (UFZ, Germany), Christine Fischer (UFZ, Germany)

In the last centuries, most rivers and floodplains have been severely modified to optimize for human use, resulting in a decrease in the ecological status and relating ecosystems services. Management plans today have to be integrative regarding many aspects from different disciplines. The assessment of multiple ecosystem services (ES) across ecosystems (from aquatic to terrestrial) combines methods from different scientific disciplines (e.g. hydrology, biology, agriculture and land use, landscape planning). Here, the concept of ES offers a new approach to solve this complex decision-making process by enabling a comparison of management options across disciplines. In the session, we want to give a platform to different methods of ES evaluation and their joint analysis. Presentation can deal with ES assessments in rivers and floodplains, with the analysis of synergies and trade-offs of ES, or ES as communication tool in decision-making processes.

SP08: Towards the integration of interdisciplinary research networks in restoration projects for riverine landscapes

Convenors: Christiane Schulz-Zunkel (UFZ, Germany), Mario Brauns (UFZ, Germany), Carolin Seele (Uni. Leipzig, Germany)

Near-natural rivers and their floodplains are biodiversity hotspots and provide numerous ecosystem services. However, riverine landscapes are faced with multiple pressures that dramatically change its functioning. Restoration creates more natural flooding areas and protects and improves the condition of riverine landscapes. It is important to accompany restoration projects with an interdisciplinary research network (IRN) in order to interpret and reflect on its effects in a scientifically sound way. This session aims at exchange on methods, results and applications in order to the successful integration and interpretation of field and laboratory data gathered from various restoration projects in riverine landscapes. It should also address the challenges and lessons to be learnt. Thus it gives the possibility to present work relevant for restoration in riverine landscapes across different countries related to biodiversity and ecosystem services.

SP09: eDNA, an emerging tool for river assessment, biodiversity research and conservation

Convenors: Point Didier (BOKU Vienna, Austria)

Since its first application to macroorganisms, environmental DNA (eDNA) has increasingly appeared to be a promising non-invasive method for improving aquatic biodiversity monitoring. With the emergence of next-generation sequencing platforms and the use of universal PCR primers (eDNA metabarcoding), large collections of taxa can be identified via a single analysis. This not only offers the possibility to detect rare or evasive species but also allows the rapid biodiversity assessment of large aquatic communities. In the case of water samples collected in rivers, eDNA contains both intra-organism DNA (e.g., small planktonic organisms) and extra-organism DNA (e.g., from fish) which can be cellular or extracellular and degraded. For macroinvertebrates, eDNA is mainly extracted from bulk samples. The use of this technic is now the subject of many works demonstrating its great interest but also the problems raised by its application in river system (e.g. eDNA detection distance).

SP10: Thermal links to hydromorphology and freshwater ecology

Convenors: Davide Vanzo (EAWAG, Switzerland), Roser Casas-Mulet (TU Munich, Germany), Stephen Dugdale (University of Nottingham, UK), Kate Mathers (EAWAG, Switzerland)

Ongoing pervasive anthropogenic pressures result in alterations in hydrological, thermal and sediment river regimes. Such alterations will potentially be exacerbated by the forecast of prolonged durations of warmer periods driven by climate change. Such unprecedented global changes in aquatic systems call for immediate actions to develop effective climate adaptation strategies. Understanding the interactive links and the feedbacks between temperature, hydromorphology and freshwater ecology, is therefore a key task for both scientists and river managers. In this context, we solicit contributions on river temperature research and its links to river hydromorphology and/or ecology. Potential topics of interest are, but not limited to, sediment and thermal effects on river biota, hydro-morphological drivers of thermal heterogeneity and temperature integration in river habitat modelling.

SP11: Rivers in the industrial era

Convenors: Gertrud Haidvogl (Boku Vienna, Austria), Goncalo Duarte (University of Lisbon, Portugal)

During the late 19. and 20th century, societal imprint on rivers increased at an unprecedented pace and intensity. The industrialization of rivers weakened the century long relationship between societies and their local and regional rivers. For example, power grids supported the transfer of electricity to consumers far away from production. Heavy machinery driven by fossil fuels enabled systematic river channelization for shipping and flood protection. Fish often lost its importance as local food resource because supply shifted to resources imported by steam ships or railways. On a global scale, freshwater biodiversity changed and rivers became ecologically degraded. These general trends exhibited local and regional differences, depending on diverse and intertwined environmental and societal processes. Investigating such trajectories can help to better understand different developments of river systems and their present status.

SP12: Saving Large Rivers as Ecological Corridors - Management and Restoration

Convenors: Thomas Hein (Boku Vienna, Austria), Paul Meulenbroek (Boku Vienna, Austria), Daniel Trauner (Boku Vienna, Austria)

Large river systems are lifelines connecting a multitude of countries and bioregions, characterizing landscapes, providing resources, and habitat for flora and fauna. They represent a historic, economic and natural heritage of human society. One of their natural characteristic is to act as a migration route and thus, as ecological corridor for biota along their watercourses and the adjacent wetlands. Especially fish are excellent bio-indicators for the functionality of ecological corridors. Their populations have suffered substantially from overfishing, pollution, habitat destruction and disruption of their migration routes. To counteract the destruction of these corridors concerted transnational investigations, management plans and actions for their restoration as well as supportive conservation measures are highly needed.

SP13: Emerging challenges for wild fish populations and their implications in the context of fisheries management

Convenors: Günther Unfer (Boku Vienna, Austria), Florian Borgwardt (Boku Vienna, Austria), Kurt Pinter (Boku Vienna, Austria)

Human activities that negatively affect habitat quality of fish through a variety of pressures such as hydro-morphological alterations resemble the major problem for wild fish populations. Next to these, unsustainable fisheries use, the reestablishment of (formerly) endangered piscivorous predators (e.g., cormorants, otters), and the spreading of invasive fish species represent threats to wild fish populations challenging their management. Emerging issues such as chemical and parasitological problems associated with climate change impacts raise additional challenges and cause substantial problems for natural fish stocks. This session will focus on the emerging issues and will provide a dialogue platform for researchers working on these heterogeneous topics, conjointly dealing with the ecology and future management of wild fish populations.

SP14: Mitigating ecological impacts in a flow-altered world

Convenors: Daniel Hayes (University of Lisbon, Portugal), Miguel Moreira (University of Lisbon, Portugal), Alban Kuriqi (University of Lisbon, Portugal), Lisa Schülting (Boku Vienna, Austria), Stefan Auer (Boku Vienna, Austria), Franz Greimel (Boku Vienna, Austria)

The growing demand for water resources has disrupted the natural flow regime and associated hydro-morphological processes, resulting in heavily regulated river systems. Diverse riverine organism groups serve as valuable indicators for diagnosing aquatic ecosystem health, as they respond well to hydrological alterations occurring from inter-annual (e.g., environmental flow) to sub-daily (e.g., hydropeaking) time scales. Thus, biota can be used for the assessment of flow alteration impacts as well as defining ecological rehabilitation or restoration measures. Although a significant amount of research has studied hydro-ecological relationships, many knowledge gaps remain, especially regarding the efficiency of mitigation measures which also incorporate the trade-offs between ecology, economy and other stakeholders. This session aims to advance the assessment of environmental impacts of water resources infrastructure, develop creative mitigation measures, and restore riverine ecosystems.

SP15: Natural small water retention measures: can we assess impacts on a catchment scale?

Convenors: Tomasz Okruszko (Warsaw university of Life Science, Poland), Primoz Banovec (University of Ljubljana, Slovenia), Mateja Skrejanec (University of Ljubljana, Slovenia), Eva Feldbacher (WCL, Austria), Damiano Baldan (WCL, Austria)

Natural Small Water Retention Measures (NSWRMs) can retain water in the landscape and release it gradually, thus affecting key riverine-provided ecosystem services. Those provisions may improve river ecological status and decrease risk of droughts and floods. However, a discrepancy exist between the local, single measure functioning and the interactions between multiple sets of measures at catchment scale. Therefore, River Basin Management Plans and other relevant policy document are hardly considering NSWRMs as valuable options in the planning process. GIS-based technology and distributed hydrological models can be the useful tools to bridge this knowledge gap, providing the policy makers valuable supporting information on effectiveness at the catchment scale. During this session we will exchange so far achieved results and share important questions for incorporation of NSWRM into the river basin planning practice.

SP16: Rivers: from Source to Sea

Convenors: Chris Bradley (University of Birmingham, UK)

This session aims to span the River - Sea continuum bringing together interdisciplinary studies that span the physical, chemical, and biological sciences linking river catchments and transitional zones to the coastal sea. These dynamic environments are changing rapidly and experiencing multiple pressures: through climate change, rising sea level, river regulation, and changing catchment land use and management. In responding to these pressures, more research is required to understand how these systems are evolving. For example, what are the impacts of catchment dynamics on marine and transitional systems downstream (and vice versa)? The session aims to provide a platform for exchange of findings from research that provides a perspective on the wider River - Sea continuum and hence advance our understanding of system functioning from a transboundary perspective to provide the science that can underpin better-informed and holistically engaged environmental protection.

SP17: S.M.A.R.T.: Science for the Management of Rivers and their Tidal systems. Outcomes from a 9-years international doctoral programme in interdisciplinary river science

Convenors: Guido Zolezzi (University of Trento, Italy), Geraldene Wharton (Queen Mary University of London, UK), Franz Hölker (IGB Berlin, Germany), Gregorio Alejandro López Moreira Mazacotte (University of Trento, Italy), Alyssa Jennifer Serlet (University of Trento, Italy)

SMART (, a multidisciplinary, 9-years joint doctoral programme, has trained and awarded joint Ph.D. degrees to 38 candidates, supervised by an interdisciplinary team of nearly 30 supervisors, encompassing engineering, fluid mechanics, hydrology, geomorphology, ecology, physiology to biogeochemistry. It aimed to move the field of river science forward by developing research through three main cross-cutting areas: (A) Ecosystem resilience to stressors; (B) Natural functioning; (C) Rehabilitation of function. The aims of the session are (1) to present and share with a broader community key research outcomes from SMART, (2) to share lessons learned in training young interdisciplinary researchers, and (3) to reinforce the worldwide network initiated within SMART, encouraging involvement of interested researchers. Contributions are primarily welcomed from SMART Alumni, but they are also open to other researchers proposing contributions fully within the spirit of the session

SP18: Ecological and social landscape-scale drivers of freshwater biodiversity: Novel findings and future challenges

Convenors: Rafaela Schinegger (Boku Vienna, Austria), Dana M. Infante (Michigan State University, USA)

Understanding of landscape influences on freshwaters and their inhabiting organisms has advanced substantially due to greater availability of large-scale ecological datasets, innovations in analytics, new data management technologies, and many important studies that have tested and applied the landscape approach in different systems globally. Additionally, research is beginning to occur that couples ecological knowledge with knowledge of socioeconomic factors also important to freshwater biodiversity. This session showcases advances to this understanding by offering insights into multi-scale landscape drivers influencing aquatic biodiversity within single river basins, through entire regions, and by cross-continental comparisons, along with novel analytical techniques for addressing hierarchical relationships among influences. Results represent state-of-the-knowledge on (multiple) landscape drivers on freshwater biodiversity, offer new strategies for protection and restoration of habitats, and point to critical management gaps and data needs, including critical information on a diverse array of social processes that could aid in efforts to conserve freshwater biodiversity.

SP19: Characterising riparian vegetation status and pressures

Convenors: Marta Gonzalez del Tanago (Universidad Politécnica de Madrid, Spain), Tenna Riis (Aarhus University, Denmark), Tomasz Okruszko (Warsaw University of Life Sciences, Poland)

Riparian vegetation is a critical component of riverine landscape and thus its structure and change provide useful information on the underlying changes in the fluvial system. Throughout history, riparian areas have been heavily managed and have consequently experienced widespread degradation. Recognizing the importance of riparian vegetation has resulted in much research and their structure and change provide useful information on the underlying changes in the fluvial system. This session invites studies on riparian vegetation, notably on the tools to assess status (i.e. structure, function and of related ecosystem services), pressures and changes, across all spatial and temporal scales using different methodological approaches (field, modelling, remote sensing, etc.) in a variety of geographic settings.

SP20: Riparian ecosystems management and restoration

Convenors: Ragnhildur Sigurdardottir (Reykjavik Academy, Iceland), Roland Jansson (Umeå University, Sweden)

Riparian ecosystems comprise the physical environment and biological communities that lay at the interface of freshwater and terrestrial systems. They are recognised as ecosystems that are highly diverse and contain specialist ecological communities, as well as providers of multiple ecosystem services. Riparian ecosystems have been heavily managed and have consequently experienced widespread modification over the last centuries. Recognizing of the importance of riparian ecosystems in providing ecosystem service has resulted in many efforts to develop a wide variety of management practices. This session invites presentations on riparian ecosystem management through different issues: current management, legislation, restoration measures, genetic conservation, applied tools and indicators, public and stakeholders’ inclusion, development of innovative management plan and financial instruments, etc.

SP21: Educated future: teaching about rivers and its implications for sustainable river management

Convenors: Joanna Zawiejska (Pedagogical University of Cracow, Poland), Lorenzo Picco (University of Padova, Italy)

As implementing river restoration projects and sustainable river management require public acceptance and stakeholder participation it has become evident that social perceptions of rivers and river processes are an important element in the success of such efforts. With many perception studies focused on adult members of the public, it is interesting to explore how perceptions and attitudes towards rivers are shaped and influenced by the formal education systems in different countries. From pre-school to university levels, all students are instructed directly and indirectly about rivers, their dynamics as well as their role and significance to society. The content, consistency and contexts of the messages that are delivered through curricula and syllabi across subjects and disciplines to a large proportion of the public are likely to effectively shape young people’s knowledge and attitude towards rivers, and influence their future behaviours. This session invites contributions on how river science is taught (including examples of both successes and failures), river perceptions by students and teachers, and the implications of the current formal education about rivers for the river environment and the society in the future.

SP22: River resilience and the Anthropocene

Convenors: David Gilvear (University of Plymouth, UK), Andy Large (Newcastle University, UK), Martin Thoms (University of New England, Australia)

This session will explore the concept or river resilience and the usefulness of the concept for managing rivers in the Anthropocene. It will explore river resilience in terms of hydro-geomorphological, ecological and social systems. Issues to be discussed will include resilience of what river system components and to what disturbances and whether resilience offers a new paradigm or is just a reframing of existing concepts. The following papers will be presented:

SP23: “Future visions” for large rivers

Convenors: Clifford A Ochs (Oxford University, Mississippi); Mike Delong (Winona State University), Andrea Funk (Boku Vienna)

To “future vision” is to imagine possibilities. In this session, we seek to imagine what is possible in a future world under alternative trajectories or scenarios for the state of large river systems. What realistic visions of future large river system conditions should we consider, and then aim to avoid or try to produce? How should these visions inform research directions, planning, and management? In a social-ecological context, how can and should alternative stakeholder or community perspectives be included in the visioning process? For this session, we invite contributed talks that explore alternative visions for future states of large river systems, under different premises and weighing different potentialities.

SP24: Efficient sets of hydromorphological measures in the WFD - Lessons learned from monitoring programs in the alpine region

Convenors: Walter Reckendorfer (VERBUND Hydro Power GmbH)

Since the implementation of the water framework directive in 2000, member states expended considerable time and resources to improve the ecological status of water bodies. In the alpine region the focus was on hydromorphological measures as the chemical status of most waterbodies was already good. Alone in Austria more than 250 million Euro have been invested in such measures in order to reach the good ecological status. The aim of this session is to review current implementation efforts. Within the first management period of the EU-WFD (2009-2015), "restoring the longitudinal connectivity" was strongly prioritised in the alpine region, but hydrological measures such as providing sufficient e-flow as well as morphological measures in order to restore type-specific habitats have also been undertaken. We appreciate examples from the alpine region or comparable water bodies gathered in research projects or monitoring programs. Individual case studies are welcomed, but comprehensive data sets allowing a comparable approach will be given priority.

SP25 (combined with world cafe): Nature-based solutions at different scales in urban and rural river basins

Convenors: Jochen Hack (TU Darmstadt, Germany), Barbara Schröter (Leibniz Centre for Agricultural Landscape Research, Germany)

Nature-based solutions are actions to protect, sustainably manage, and restore natural or modified ecosystems. They often address societal challenges more effectively and adaptively than merely technical solutions, while simultaneously providing human well-being and biodiversity benefits. Nature-based solutions (NBS) to socio-ecological problems in urban and rural riverscapes are presented and discussed. 3-4 introductory talks by international experts are followed by a world cafe in order to interactively discuss and gain key insights from inter- and transdisciplinary research and practice. NBS from the local to the regional scale are addressed with regard to (ex. questions): How differs the design of NBS at different scales? Are there synergies of actions at different scales? How can integration be achieved? How to engage actors in problem definition and solution development? What are dominant ecological processes at different scales? It is aimed for a common publication as a product.

General sessions

GS.1 Climate change impacts

GS.2 Land use impacts

GS.3 Urban streams and rivers

GS.4 Invasive species in rivers

GS.5 Contaminants in riverine systems

GS.6 Interactive effects of stressors

GS.7 Hydrological and morphological impacts

GS.8 Monitoring and Assessment

GS.9 Aquatic Ecosystem Restoration

GS.10 Conservation and management

GS.11 Ecosystem Services

GS.12 Citizen Science and public participation

GS.13 Environment - biota interactions

GS.14 Dynamics of communities and populations and their interactions

GS.15 Socio-ecological interactions

GS.16 New methodological approaches

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