Scientific Publications

This section gives the overview of scientific publications. Publications are listed in reversed chronological order, i.e. new ones appear on top.
For each publication you will find title, abstract, full reference and DOI.
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Information for this can be found through the DOI.

Plant traits relevant to fluvial geomorphology and hydrological interactions (O'Hare et al. 2015)

Plants can slow water and trap sediment with their canopies and stabilise sediment with their roots. These influences are mediated by the characteristics or traits of the vegetation. Here, we review and investigate the flexibility, size, root form, clonal growth, perennation and Ellenberg F values of 459 European riverine species, considering their role in physical and ecological processes.

Vegetation–hydrogeomorphology interactions in a low-energy, human-impacted river (Gurnell & Grabowski 2015)

The geomorphological dynamics of rivers have been traditionally explained largely by the physical processes of water flow, and sediment erosion and deposition, but the significant role of a third element, vegetation, in driving geomorphological changes has been increasingly highlighted recently. However, few studies have documented how both aquatic and woody riparian plants interact with fluvial processes to induce landform development and initiate channel adjustment. This paper presents analyses of historical maps, recent aerial images and field observations from the River Frome (Dorset, UK), which, as a result of human pressures, has been subject to an increased supply of sand and finer sediment, particularly over the last 50–60 years.

A conceptual model of vegetation–hydrogeomorphology interactions within river corridors (Gurnell et al. 2015)

We propose a conceptual model of vegetation–hydrogeomorphology interactions and feedbacks within river corridors (i.e. river channels and their floodplains) that builds on previous similar hydrogeomorphologically centred models. The model is illustrated using three example reaches from rivers within different biogeographical zones of Europe, and its potential application in the context of river management and restoration/rehabilitation is discussed. 

Diagnosing problems produced by flow regulation and other disturbances in Southern European Rivers: the Porma and Curuenõ Rivers (Duero Basin, NW Spain) (González del Tánago et al. 2016)

This research presents an analysis of river responses to flow regulation and other disturbances over time. The study was conducted in the Porma and Curuenõ rivers, using the hierarchical multi-scale process-based framework developed within the European REFORM Project. The characterisation of the rivers at the landscape unit, segment and reach scales under current and past conditions by different hydro-morphological indicators has provided a useful approach to (1) identify where and how main channel adjustments have occurred, (2) establish causal relationships at different scales and (3) discuss potential future scenarios and restoration strategies. 

Reconstructing temporal changes and prediction of channel evolution in a large Alpine river: the Tagliamento river, Italy (Ziliani & Surian 2016)

This paper focuses on the temporal elements of the REFORM hydromorphological framework, illustrating these elements with an analysis of information from the lower Tagliamento river, Italy. It presents an analysis of historical channel adjustments at segment and reach scales over the last two centuries, reflecting human pressures that are summarised but not fully developed in this paper, and an analysis of data from aerial photographs, topographic surveys, and river flow records. 

Diagnosing problems of fine sediment delivery and transfer in a lowland catchment (Grabowski & Gurnell 2016)

Fine sediment (here defined as fine sand, silt and clay) is a serious management problem in lowland rivers because of alterations to river channels, floodplains and the wider landscape. The multi-scale, complex and stochastic nature of sediment production, delivery and transport processes complicates the diagnosis of fine sediment sources, pathways and impacts. The hydromorphological assessment framework developed by the REFORM project offers a flexible approach to investigate fine sediment pressures. In this study, the framework was applied to a lowland river impacted by excess fine sediment (River Frome, Dorset, UK) to investigate likely sources and timing of sediment production, the segment-scale capacity of the river to transport sediment, and the reach-scale geomorphological response of the river. 

Assessing the societal benefits of river restoration using the ecosystem services approach (Vermaat et al. 2015)

The success of river restoration was estimated using the ecosystem services approach. In eight pairs of restored–unrestored reaches and floodplains across Europe, we quantified provisioning (agricultural products, wood, reed for thatching, infiltrated drinking water), regulating (flooding and drainage, nutrient retention, carbon sequestration) and cultural (recreational hunting and fishing, kayaking, biodiversity conservation, appreciation of scenic landscapes) services for separate habitats within each reach, and summed these to annual economic value normalized per reach area. 

Plant trait characteristics vary with size and eutrophication in European lowland streams (Baattrup-Pedersen et al. 2015)

Previous studies investigating community-level relationships between plant functional trait characteristics and stream environmental characteristics remain scarce. Here, we used community-weighted means to identify how plant traits link to lowland stream typology and how agricultural intensity in the catchment affects trait composition.

We analysed plant trait characteristics in 772 European lowland streams to test the following two hypotheses: (i) trait characteristics differ between plant communities in small and medium-sized streams, reflecting adaptations to different habitat characteristics, and (ii) trait characteristics vary with the intensity of agricultural land use in the stream catchment, mediated either directly by an increase in productive species or indirectly by an increase in species that efficiently intercept and utilize light.

Biogeomorphic responses to flow regulation and fine sediment supply in Mediterranean streams (the Guadalete River, southern Spain) (González del Tánago et al. 2015)

Geomorphic responses to damming are primarily determined by the magnitude of sediment transport and sediment supply alteration and by the resulting change in the balance between the two. The former change is caused by alterations in the flow regime that are caused by reservoir operations. Flow regime changes also affect the distribution and amount of riparian vegetation that, in turn, also may enhance geomorphic responses. The latter change is caused by sediment trapping in reservoirs and by the magnitude of sediment supply from watersheds that are downstream from the dam. We examined the bio-geomorphic responses to flow regulation along a Mediterranean stream located in an agricultural area of southern Spain where there is significant fine sediment erosion from adjacent hillsides. 

The effect of river restoration on fish, macroinvertebrates and aquatic macrophytes: a meta-analysis (Kail et al. 2015)

An increasing number of rivers have been restored over the past decades and several studies investigated the effect on biota. The published monitoring results have already been summarized in narrative reviews
but there are few quantitative reviews and a comprehensive meta-analysis on different organism groups and factors influencing restoration effect is missing. We compiled monitoring results and information on
catchment, river and project characteristics from peer-reviewed literature and unpublished databases to (i) quantify the effect of restoration measures on fish, macroinvertebrates and macrophytes, and (ii) identify predictors which influence restoration effect. 

Alternate bars in a sandy gravel bed river: generation, migration and interactions with superimposed dunes (Rodrigues et al. 2015)

A field study was carried out to investigate the development of alternate bars in a secondary channel of the Loire River (France) as a function of discharge variations. We combined frequent bathymetric surveys, scour chains and stratigraphical analysis of deposits with measurements and modelling of flow dynamics. The channel exhibited migrating bars, non-migrating bars and superimposed dunes. Possible mechanisms of bar initiation were found to be chutes associated with changes of bank direction and instability resulting from interactions between existing bars during the fall in water level after floods. 

The effects of increased flow and fine sediment on hyporheic invertebrates and nutrients in stream mesocosms (Jones et al. 2015)

1. River regulation and altered land use are two common anthropogenic disturbances in rivers worldwide. Alteration of the stream bed, through processes such as siltation, or of hydrology through river regulation, are likely to modify hyporheic processes or clog interstitial space and thereby affect both hyporheic invertebrates and nutrient dynamics.

2. We tested the separate and combined effects of increased flow and increased fine sediment on hyporheic water quality and invertebrates in flume mesocosms. 

The conceptual foundation of environmental decision support (Reichert et al 2015)

Environmental decision support intends to use the best available scientific knowledge to help decision makers find and evaluate management alternatives. The goal of this process is to achieve the best fulfillment of societal objectives. This requires a careful analysis of (i) how scientific knowledge can be represented and quantified, (ii) how societal preferences can be described and elicited, and (iii) how these concepts can best be used to support communication with authorities, politicians, and the public in environmental management. The goal of this paper is to discuss key requirements for a conceptual framework to address these issues and to suggest how these can best be met. 

Did You Say Reference Conditions? Ecological and Socio-economic Perspectives on the European Water Framework Directive (Bouleau & Pont 2014)

Reference conditions are a key concept in the European Water Framework Directive (WFD). The WFD stipulates that the ecological status of a given water body shall be assessed by quantifying the deviation from a set of reference conditions that represent the stable state of an ecosystem in the absence of significant human disturbance. This concept is subject to criticism from several authors, particularly because underlying ecological concepts are weak and the distinction between natural variability and the effects of anthropogenic activities on ecosystem function will become increasingly artificial.

A Method for Characterizing the Stream Flow Regime in Europe (Bussettini et al 2014)

Starting from a literature review and an analysis of eco-hydrological classification methods widely used nowadays, this work aims to propose a stream classification based on the flow regime with characteristics of representativeness within the European continent. The proposed approach classifies streams based on the combination of different criteria: intermittency, river-aquifer interaction and prevailing flow sources. 

Development and Application of a Multi-scale Process-based Framework for the Hydromorphological Assessment of European Rivers (Gurnell et al. 2014)

Many current river assessment methods emphasise the river ‘reach’ scale (a fixed length of river of the order of a few hundred meters) and provide a wealth of useful information that characterises the river corridor at the time of survey. However, they also have several limitations when they are used for understanding physical processes and causes of river alteration. A multi-scale, process-based framework is needed, which incorporates reach scale information into a larger spatial and temporal assessment of the controls on reach dynamics, and a process-based interpretation of the contemporary status of reaches, their historical dynamics and their likely future trajectories of adjustment. 

Impacts and indicators of change in lotic ecosystems (Friberg 2014)

Fresh waters have seen the largest decline in biodiversity of any ecosystem, with lotic ecosystems particularly impacted by human activities. The main drivers of environmental change relate primarily to agriculture, urbanization, and industrial production that have resulted in severe habitat degradation in streams and rivers worldwide. The increasing impact of climate change and invasive species has put further pressure on these systems.

Assessing channel response of a long river influenced by human disturbance (Latapie et al 2014)

This paper describes an approach to assess channel changes of a long anthropogenised river (the Middle Loire River) over decadal timescales. Channel changes are evaluated along geomorphically homogeneous river reaches. The classic geomorphic parameters (active channel width, bed slope, grain size) are complemented with parameters extracted from a 1D hydraulic model: width–depth ratio, effective bed shear stress and specific stream power calculated for the biennial discharge assimilated to bankfull flow conditions. 

A review of assessment methods for river hydromorphology (Belletti et al 2014)

Numerous hydromorphological assessment methods have been developed in different countries during recent decades, with notable differences in their aims, scales, and approaches. Although these methods are increasingly applied to support river management, the strengths and limitations have been insufficiently investigated. This review of 121 methods analyses hydromorphological assessment methods dating from 1983 to 2013, identifying their main strengths, limitations, gaps, the potential to integrate different approaches, and the need for further improvements. 

Mountain river restoration measures and their success(ion): effects on river morphology, local species pool, and functional composition of three organism groups (Januschke et al 2014)

We investigated temporal effects of restoration on river morphology, on species and functional com-position of benthic invertebrates, floodplain vegetation and carabid beetles at three study sites in themountain river Lahn (Germany). We sampled restored and nearby non-restored sections 3–5 years and7–9 years after restoration. In the restored sections, instream microhabitat heterogeneity was higherdue to the increased presence of finer substrates, while cobbles and coarse gravel were still domi-nant. Instream habitat composition did not change between the two sampling events.

Do adult and YOY fish benefit from river restoration measures? (Lorenz et al 2013)

 We analyzed the effects of 36 river restoration projects on fish assemblages. We expected increased reproduction in restored river reaches leading to a sustainable increase in the total amount of fishes. The restored reaches are situated in small to medium-sized rivers in lowlands and lower mountainous areas in Germany. Restoration measures considerably changed river morphology and created more natural conditions by improving habitat diversity. For each restored reach, we sampled an upstream unrestored counterpart that resembled the restored reach before the restoration measures were implemented. 

Groundwater impact on environmental flow needs of streams in sandy catchments in the Netherlands (Hendriks et al 2014)

During recent years, water managers and water users in the Netherlands experienced water shortages in numerous streams. Besides low rainfall amounts and high temperatures, anthropogenic alterations to the groundwater system are also responsible for the reduced baseflow in streams. These alterations may reduce resilience and increase a risk to streams as more droughts are expected in the Netherlands due to climate change. We propose a methodology to assess the impact of groundwater-related alterations and climate change on baseflow and environmental flow needs (EFN).

Challenges to barbel population resilience due to hydrological alteration (Gallo et al 2014)

This study aims to evaluate how the habitat of the Iberian barbel (Luciobarbus bocagei) has changed over the last nine decades in a reach of the River Duero in Toro (Zamora). The available physical habitat through different streamflows was quantified as the wetted area potentially usable by adult barbel with maximum preference (weighted usable area [WUA]). Historical time series of streamflows were used to generate a time series of habitat. Flow data were studied from 1912 to 2008, period being divided into three sub-periods.

Field experiment on alternate bar development in a straight sand-bed stream (Eekhout et al 2013)

Alternate bars in rivers and streams develop as a result of differences in length scales involved in the adjustment of flow and sediment transport to irregularities of the bed. The amount of field evidence supporting theoretical insights is highly limited. Here, we present results from a large-scale field experiment in a 600 m long straight reach. Over a period of almost 3 years, the channel was allowed to evolve autogenously from initially flat bed conditions, subject to discharge variation. Alternate bars developed within 8 months from the start of the experiment.