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.

The use of remote sensing to characterise hydromorphological properties of European rivers (Bizzi et al. 2016)

Remote sensing (RS) technology offers unparalleled opportunities to explore river systems using RADAR, multispectral, hyper spectral, and LiDAR data. The accuracy reached by these technologies recently has started to satisfy the spatial and spectral resolutions required to properly analyse the hydromorphological character of river systems at multiple scales. Using the River Hierarchical Framework (RHF) as a reference we describe the state-of-the-art RS technologies that can be implemented to quantify hydromorphological characteristics at each of the spatial scales incorporated in the RHF (i.e. catchment, landscape unit, river segment, river reach, sub-reach—geomorphic and hydraulic units). 

Fish community responses and the temporal dynamics of recovery following river habitat restorations in Europe (Thomas et al. 2015)

Considerable uncertainty exists regarding the ability of reach-scale habitat restorations to promote ecological integrity and affect community composition in degraded streams and rivers and the time scales at which these effects take place. Restoration of habitats on the reach scale (hundreds of meters to a few kilometers) is expected to support threatened species because many of them are habitat specialists. In contrast, generalist species are predicted to be replaced in restored reaches. We used a large data set for 62 reach-scale restoration projects in 51 stream systems in Germany, Switzerland, and Liechtenstein and analyzed the changes in fish community composition induced by the restorations in terms of species richness, species turnover, Brillouin diversity index, total fish abundance, and proportion of alien and endangered species. 

The geomorphological context and impact of the linear emergent macrophyte, Sparganium erectum L.: a statistical analysis of observations from British rivers (Gurnell et al. 2013)

This paper explores the geomorphological context and impact of the widely-occurring, linear emergent macrophyte, Sparganium erectum. Forty-seven sites across Britain were selected for field investigation, spanning the range of environmental conditions within whichSparganium erectum had been found to be present in previous analyses of national data sets. A combination of descriptive graphs and statistics, principal components analysis, and Kruskal–Wallis tests were used to explore the large multivariate data set collected at the 47 sites.

Species sorting drives variation of boreal lake and river macrophyte communities (Alahuhta et al. 2015)

Metacommunity paradigms are increasingly studied to explain how environmental control and spatial patterns determine variation in community composition. However, the relative importance of these patterns on biological assemblages among different habitats is not well known. We investigated the relative roles of local, catchment and spatial variables based on overland and watercourse distances in explaining the variation of community structure of lake and river macrophytes in two large river basins at two spatial extents (within and across river basins). 

Response of fish assemblages to hydromorphological restoration in central and northern European rivers (Schmutz et al. 2015)

European rivers are highly degraded and restoration efforts are becoming more frequent. However, only few restoration projects have been rigorously evaluated so far. We investigated the response of fish assemblages to hydromorphological restoration measures including river widening, creation of instream structures, flow enhancement, remeandering and side-channel reconnection. We sampled 15 rivers with pairs of degraded and restored sites and calculated the effect sizes (i.e., restored–degraded) for species richness, species diversity, fish density and habitat traits. 

A multi-scale hierarchical framework for developing understanding of river behaviour to support river management (Gurnell et al. 2016)

This paper introduces this special issue of Aquatic Sciences. It outlines a multi-scale, hierarchical framework for developing process-based understanding of catchment to reach hydromorphology that can aid design and delivery of sustainable river management solutions. The framework was developed within the REFORM (REstoring rivers FOR effective catchment Management) project, funded by the European Union’s FP7 Programme. Specific aspects of this ‘REFORM framework’ and some applications are presented in other papers in this special issue.

Environmental controls of plant species richness in riparian wetlands: implications for restoration (Audet et al. 2015)

Wetland restoration projects often focus on mitigating losses of nutrients (nitrogen and phosphorus) toward downstream aquatic recipients and, so far, there is no clear guidance on how to restore environmental conditions to improve biodiversity values in the restored areas. However, to provide such guidance, it is necessary to obtain a better understanding of the factors driving biodiversity in natural wetlands. For this purpose, we investigated plant community characteristics in 35 plots located at 10 Danish riparian wetlands to identify critical factors required to sustain species diversity.

Impacts of habitat degradation and stream spatial location on biodiversity in a disturbed riverine landscape (Göthe et al. 2015)

The ongoing degradation of freshwater habitat quality and subsequent losses of biodiversity is alarming. One key to successful freshwater management is to understand how different scale-dependent diversity components (i.e. γ-, α- and β-diversity) change along present-day anthropogenic impact gradients. We used macrophyte, fish and macroinvertebrate data from Danish lowland streams to investigate whether (1) high connectivity in reaches situated in lower parts of the stream network (downstream sites) generates high α-diversity, while dispersal limitation and high habitat heterogeneity across the more isolated upper reaches (headwater sites) generate high β-diversity, (2) γ-, α- and β- diversity decrease with increasing hydromorphological impact and (3) high connectivity in downstream reaches buffers against impacts on biodiversity.

Climate change effects on lowland stream flood regimes and riparian rich fen vegetation communities in Denmark (Thodsen et al. 2014)

There is growing awareness that an intensification of the hydrological cycle associated with climate change in many parts of the world will have profound implications for river ecosystem structure and functions. In the present study we link an ensemble of regional climate model projections to a hydrological model with the aim to predict climate driven changes in flooding regimes in lowland riparian areas.

Structural and functional responses of floodplain vegetation to stream ecosystem restoration (Göthe et al 2015)

 Most river restoration projects have applied relatively small-scale measures focused on improving specific instream conditions, with only limited outcomes for biodiversity in rivers and their adjacent riparian habitats. Here, we investigate the effects of both small- and large-scale restoration projects on floodplain vegetation across 20 European catchments. We focused on the roles of different restoration parameters (i.e., the number, spatial extent and type of restoration measure applied and restoration age) and specific environmental characteristics in regulating changes in plant diversity and trait composition following restoration.

Indicators of river system hydromorphological character and dynamics: understanding current conditions and guiding sustainable river management (González del Tánago et al 2016)

A set of multi-scale, process-based hydromorphological indicators of river character and dynamics has been developed to support river management and restoration activities. Indicators are selected to represent key hydromorphological processes at each spatial scale, i.e., catchment, landscape unit, river segment, river reach. Their evaluation allows identification of the cascade of these processes through the spatial units and the historical changes in their propagation as a consequence of natural or human induced hydromorphological changes.

Contrasting the roles of section length and instream habitat enhancement for river restoration success: a field study of 20 European restoration projects (Hering et al. 2015)

Restoration of river hydromorphology often has limited detected effects on river biota. One frequently discussed reason is that the restored river length is insufficient to allow populations to develop and give the room for geomorphological processes to occur.

We investigated ten pairs of restored river sections of which one was a large project involving a long, intensively restored river section and one represented a smaller restoration effort. The restoration effect was quantified by comparing each restored river section to an upstream nonrestored section. We sampled the following response variables: habitat composition in the river and its floodplain, three aquatic organism groups (aquatic macrophytes, benthic invertebrates and fish), two floodplain-inhabiting organism groups (floodplain vegetation, ground beetles), as well as food web composition and land–water interactions reflected by stable isotopes.

Advances on modelling riparian vegetation—hydromorphology interactions (Solari et al. 2015)

Riparian vegetation actively interacts with fluvial systems affecting river hydrodynamics, morphodynamics and groundwater. These interactions can be coupled because both vegetation and hydromorphology (i.e. the combined scientific study of hydrology and fluvial geomorphology) involve dynamic processes with similar temporal and spatial scales. To predict and assess the consequences of restoration measures, maintenance operations or human pressures in rivers, managers and planners may wish to model these interactions considering the different and interdisciplinary implications in the fields of ecology, geomorphology and hydrology. In this paper, we review models that are currently available and that incorporate the processes that relate riparian vegetation to hydromorphology.

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.