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 role of benthic microhabitats in determining the effects of hydromorphological river restoration on macroinvertebrates (Verdonschot et al. 2015)

Despite the large number of river restoration projects carried out worldwide, evidence for strong and long-term positive ecological effects of hydromorphological restoration on macroinvertebrates is scarce. To improve the understanding of the success and failure of restoration measures, a standardized field study was carried out in nineteen paired restored and degraded river sections in mid-sized lowland and mountain rivers throughout Europe. We investigated if there were effects of restoration on macroinvertebrate biodiversity, and if these effects could be related to changes in microhabitat composition, diversity and patchiness. 

Bundles of stream restoration measures and their effects on fish communities (Simaika et al. 2015)

At the global scale, substantial numbers of stream restoration projects have been carried out in the last decades, utilizing significant investment. Yet comparative studies on the effectiveness of stream restorations are rare, and the few existing studies show inconsistent results. A common flaw in these studies is that the restoration projects investigated often include widely varying sets of restoration measures, which may lead to contradictory findings on restoration outcomes. To overcome this flaw we propose an approach to identify, bundles of restoration measures based on cluster analysis. We applied our approach to a comprehensive dataset of 61 Central European stream restoration projects and compare the restoration effects of these different bundles of restoration measures on fish communities. 

Fuzzy cognitive mapping for predicting hydromorphological responses to multiple pressures in rivers (Lorenz et al. 2015)

Different pressures often co-occur in rivers and act simultaneously on important processes and variables. This complicates the diagnosis of hydromorphological alterations and hampers the design of effective restoration measures. Here, we present a conceptual meta-analysis that aims at identifying the most relevant hydromorphological processes and variables controlling ecological degradation and restoration. For that purpose, we used fuzzy cognitive mapping based on conceptual schemes that were created according to 675 scientific peer-reviewed river hydromorphology studies.

Constructing, evaluating and visualizing value and utility functions for decision support (Reichert et al. 2013)

Formal methods of decision analysis can help to structure a decision making process and to communicate reasons for decisions transparently. Objectives hierarchies and associated value and utility functions are useful instruments for supporting such decision making processes by structuring and quantifying the preferences of decision makers or stakeholders. Common multi-attribute decision analysis software products support such decision making processes but they can often not represent complex preference structures and visualize uncertainty induced by uncertain predictions of the consequences of decision alternatives. To stimulate strengthening these aspects in decision support processes, we propose a set of visualization tools and provide a software package for constructing, evaluating and visualizing value and utility functions. 

Classification of river morphology and hydrology to support management and restoration (Rinaldi et al 2016)

As part of an hierarchical, multi-scale, hydromorphological framework for European rivers that has been developed within the REFORM project, a procedure for classifying rivers has been devised. The procedure includes components that categorise river channel morphology, floodplain morphology, flow regime, and groundwater—surface water interactions, and is designed for operational use in the context of river management. 

On the estimation of the sediment transport and sediment budget in a long reach: application on the Middle Loire River, France (Camenen et al. 2016)

Sediment load and budgets are a fundamental component of the process-based hydromorphological framework developed by the REFORM project, and are needed to accurately assess the current condition of a river, its sensitivity to change, and its likely future evolutionary trajectory. This paper presents an evaluation of three different methods for estimating both bedload sediment transport and bed-material budget within river channels, using the Middle Loire River as a case study. 

Automatic procedures for river reach delineation: Univariate and multivariate approaches in a fluvial context (Martínez-Fernández et al. 2016)

Segmenting the continuum of rivers into homogeneous reaches is an important issue in river research and management. Automatic procedures provide significance, objectivity, and repeatability. Although univariate techniques are frequently used to identify river reaches, multivariate approaches offer a more integrative context. Three nonparametric methods (multi-response permutation procedures (MRPP) with an advance in the significance level estimation, the Pettitt and Mann–Kendall tests) are applied for segmenting the river based on three geomorphic variables (valley width, active channel width, and channel slope) systematically measured in a GIS environment. 

Diagnosing problems induced by past gravel mining and other disturbances in Southern European rivers: the Magra River, Italy (Belletti et al 2016)

The multi-scale hierarchical framework developed within the REFORM project, for the study of the functioning of river reaches and their catchments, was applied to the Magra River catchment (Northern Tuscany, Italy). The Magra River is a quite dynamic gravel-bed river that has undergone severe channel adjustments over the last century (i.e. incision and narrowing). The REFORM framework was then applied in order to (1) explore the locations and causes of these adjustments, and (2) assess how different river reaches responded to specific human activities (i.e. land use changes, dams, gravel mining). 

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.