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.

Time is no healer: increasing restoration age does not lead to improved benthic invertebrate communities in restored river reaches (Leps et al. 2016)

Evidence for successful restoration of riverine communities is scarce, particularly for benthic invertebrates. Among the multitude of reasons discussed so far for the lack of observed effects is too short of a time span between implementation and monitoring. Yet, studies that explicitly focus on the importance of restoration age are rare.

We present a comprehensive study based on 44 river restoration projects in Germany, focusing on standardized benthic invertebrate sampling. A broad gradient ranging from 1 to 25 years in restoration age was available. In contrast to clear improvements in habitat heterogeneity, benthic community responses to restoration were inconsistent when compared to control sections. 

The Hydromorphological Evaluation Tool (HYMET) (Klösch & Habersack 2016)

River engineering structures, such as bank protection or bed sills, act as constraints on the hydromorphology of rivers and limit morphodynamic processes. Accordingly, the deviations of a river's morphology from a natural reference condition have been attributed to the degree of artificiality in the observed river section and river restoration works mainly aimed at reducing artificial constraints within the river reach.

Long-term response of salmonid populations to habitat restoration in a boreal forest stream (Van Zyll de Jong & Cowx 2016)

Assessing the sustainability of restoration measures for salmonid populations and their habitat is limited due to a lack of long-term evaluations. In this paper we report on a study to assess the effect of boulder clusters, V-dams and half-log covers on stream habitat and population abundance of Atlantic salmon and brook trout two decades after installation. Structures were installed in Joe Farrell’s Brook, Newfoundland Canada in 1993 and fish population and habitat parameters were initially measured annually from 1993 to 1995. All stream sites were re-sampled in 2014. 

Quantifying the relative importance of natural variables, human disturbance and spatial processes in ecological status indicators of boreal lakes (Alahuhta & Aroviita 2016)

Spatial processes are increasingly associated with species distributions in freshwaters. However, these processes are usually neglected in bioassessment techniques, which may introduce uncontrolled variation in ecological indicators used to express human disturbance. We used partial linear regression to quantify the relative importance of natural variables, human disturbance and spatial variables in structuring variation in boreal lake status indicators based on six biological indicator groups (phytoplankton, macrophytes, diatoms, littoral and profundal macroinvertebrates and fish). 

Macrophytes in boreal streams: Characterizing and predicting native occurrence and abundance to assess human impact (Rääpysjärvi et al. 2016)

Macrophytes are a structurally and functionally essential element of stream ecosystems and therefore indispensable in assessment, protection and restoration of streams. Modelling based on continuous environmental gradients offers a potential approach to predict natural variability of communities and thereby improve detection of anthropogenic community change. Using data from minimally disturbed streams, we described natural macrophyte assemblages in pool and riffle habitats separately and in combination, and explored their variation across large scale environmental gradients. 

Meander reconnection method determines restoration success for macroinvertebrate communities in a German lowland river (Lorenz et al. 2016)

Re-meandering of degraded rivers is a frequently implemented measure in river restoration. A simple solution is reconnection of old meanders; however, its success likely depends on the reconnection method. We conducted a field study to analyze the benefits of a fully reconnected (fully opened meander, blocked main channel) and a partially reconnected meander (opened downstream, pipe bypass from main channel upstream, still open main channel) for macroinvertebrate communities in a German lowland river. 

Disentangling the responses of boreal stream assemblages to low stressor levels of diffuse pollution and altered channel morphology (Turunen et al. 2016)

Non-point diffuse pollution from land use and alteration of hydromorphology are among the most detrimental stressors to stream ecosystems. We explored the independent and interactive effects of morphological channel alteration (channelization for water transport of timber) and diffuse pollution on species richness and community structure of four organism groups in boreal streams: diatoms, macrophytes, macroinvertebrates, and fish. Furthermore, the effect of these stressors on stream condition was evaluated by Ecological Quality Ratios (EQR) from the national Water Framework Directive (WFD) assessment system.

Incorporating catchment to reach scale processes into hydromorphological assessment in the UK (England & Gurnell 2016)

Hydromorphological pressures and the measures undertaken to address them are an important element of the delivery of the WFD within the United Kingdom. While assessment procedures currently employed gather useful morphological information for river reaches and their immediate margins and some process information, crucial information on key processes is missing and information gathered on the riparian zone and floodplain is limited. This article presents a newly developed framework that enables existing data to be placed within a multiscale, process-based context. 

Integrating and extending ecological river assessment: concept and test with two restoration projects (Paillex et al. 2017)

While the number of river restoration projects is increasing, studies on their success or failure relative to expectations are still rare. Only a few decision support methodologies and integrative methods for evaluating the ecological status of rivers are used in river restoration projects, thereby limiting informed management decisions in restoration planning as well as success control. Moreover, studies quantifying river restoration effects are often based on the assessment of a single organism group, and the effects on terrestrial communities are often neglected. In addition, potential effects of water quality or hydrological degradation are often not considered for the evaluation of restoration projects.

We used multi-attribute value theory to re-formulate an existing river assessment protocol and extend it to a more comprehensive, integrated ecological assessment program. We considered habitat conditions, water quality regarding nutrients, micropollutants and heavy metals, and five instream and terrestrial organism groups (fish, benthic invertebrates, aquatic vegetation, ground beetles and riparian vegetation). The physical, chemical and biological states of the rivers were assessed separately and combined to value the overall ecological state.

Fluvial Corridor Changes Over Time in Regulated and Non‐Regulated Rivers (Upper Esla River, NW Spain) (Martínez‐Fernández et al. 2016)

Over the last decades, rivers and fluvial corridors have been noticeably modified from their natural conditions. In general, damming and other in-channel human interventions have been traditionally considered as the main drivers of change. However, recent studies highlight the influence of climate, hillslope and floodplain cover changes over fluvial corridor dynamics. The present study illustrates the channel morphology and riparian vegetation responses observed in three gravel bed rivers located in the Upper Esla River, north-west of Spain. 

The effect of weirs on nutrient concentrations (Cisowska & Hutchins 2016)

The removal of a weir in 1999 from the River Nidd in Yorkshire, UK, was assessed in terms of its impact on in-stream nitrate removal along a 15.8 km long stretch of river. Models of channel hydraulics and denitrification quantified the impact on an annual basis, using, as inputs, river flow, water temperature, water quality data and cross-section geometry collected both before and after the weir was removed. 

Functional trait composition of aquatic plants can serve to disentangle multiple interacting stressors in lowland streams (Baattrup-Pedersen et al. 2016)

Historically, close attention has been paid to negative impacts associated with nutrient loads to streams and rivers, but today hydromorphological alterations are considered increasingly implicated when lowland streams do not achieve good ecological status. Here, we explore if trait-abundance patterns of aquatic plants change along gradients in hydromorphological degradation and eutrophication in lowland stream sites located in Denmark. 

Distinct patterns of interaction between vegetation and morphodynamics (van Oorschot et al. 2016)

Dynamic interaction between river morphodynamics and vegetation affects river channel patterns and populations of riparian species. A range of numerical models exists to investigate the interaction between vegetation and morphodynamics. However, many of these models oversimplify either the morphodynamics or the vegetation dynamics, which hampers the development of predictive models for river management.

River restoration and the trophic structure of benthic invertebrate communities across 16 European restoration projects (Kupilas et al 2015)

River restoration enhances not only habitat diversity in the stream channel and riparian zone, but also retention of organic matter, which together are expected to enhance aquatic-terrestrial linkages, and the range of autochthonous and allochthonous resources. Consequently, alterations of food-web structure and trophic relationships can be expected. We applied stable isotope analysis (δ13C, δ15N) to characterize changes in the trophic structure of benthic invertebrate communities between paired restored and unrestored river reaches across 16 European catchments.

Assessing restoration effects on hydromorphology in European mid-sized rivers by key hydromorphological parameters (Poppe et al. 2015)

The effects of river restoration on hydromorphological conditions and variability are often documented immediately following the restoration, but rarely properly monitored in the long term. This study assesses outcomes of 20 restoration projects undertaken across central and northern Europe for a comprehensive set of hydromorphological parameters, quantified at both larger and smaller spatial scales. For each project, we compared a restored river section to an upstream degraded section. Ten pairs of large projects were contrasted to ten similar but less extensive projects, to address the importance of restoration extent for the success of each project. 

Effects of river restoration on riparian ground beetles (Coleoptera: Carabidae) in Europe (Januschke & Verdonschot 2015)

Studies addressing the effects of river and floodplain restoration on riparian ground beetles mainly focus on single river sections or regions. We conducted a large-scale study of twenty paired restored and degraded river sections throughout Europe. It was tested (i) if restoration had an overall positive effect on total species richness, Shannon–Wiener diversity and richness of riparian, wetland and floodplain forest specialists, and (ii) if the effects depended on river and project characteristics as well as habitat differences caused by restoration. 

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).