Riverine Landscapes Research Articles

The macroinvertebrate fauna of maintained and abandoned beaver dams

Beavers and their dams, once common in small streams throughout Eurasia and North America, are returning to their original range. Beaver dams are special habitats in the aquatic-terrestrial interface, but their macroinvertebrate fauna is hardly known. This study aims to qualify and quantify the invertebrate fauna of beaver dams, taking into account the maintenance status of the dams. Nine different areas covering the top, middle and base zones of eight maintained and eight abandoned beaver dams were sampled using a specially designed suction device. The invertebrate community of beaver dams proved to be diverse and predominantly rheophilic. Community composition reflects higher flow velocities in streamside habitats; this gradient is more pronounced in maintained than in abandoned dams. Shredders are the most abundant feeding type, but they are less frequent in streamside habitats, in particular in those of maintained dams, where passive filter feeders prevail. Terrestrial/Semiaquatic taxa colonising hygropetric areas were found in streamside habitats especially of abandoned dams. Our results underline that beaver dams provide a wide variety of environmental conditions and habitat types, which enhance biodiversity in small streams and their floodplains. Beaver dams in riverine landscapes should therefore be much more valued in floodplain conservation and management.

The Heterogeneity of Ecosystem Services across the Riverine Landscape of the Koshi River Basin, Nepal

A foundational tenet of the ecosystem services concept is that they arise from biophysical processes. Riverine landscapes are process-response systems where river flow and geomorphology generate a heterogeneous physical template that influences ecological processes, suggesting that the supply of ecosystem services in riverine landscapes should be congruent with the character and heterogeneity of the physical template. In this study, we examine the congruency between the physical template (river functional process zones; FPZs) and the supply of river flow dependent ecosystem services from riverine landscapes of the Koshi River Basin, Nepal. The supply of ecosystem services was congruent with FPZs. Social factors were shown to mediate the use and value of ecosystem services between FPZs. Heterogeneity of the physical template interacts with place, social activity, and demography to influence the use and potential value of ecosystem services across the riverine landscape. These spatial patterns of greater use of some types of riverine ecosystem services in certain areas of the riverine landscape are indicative of a highly coupled agricultural or “green loop” social-ecological system (SES) and show that maintaining riverine template heterogeneity is an important element of this green loop SES that supports 40 million people in the Koshi River Basin.

Effect of Soil Agricultural Use on Particle-Size Distribution in Young Glacial Landscape Slopes

In the literature, mainly particle-size distribution (PSD) analyses in the soil catenas, of e.g., moraine and riverine landscapes were discussed. Analysis and comparison of PSD in moraine (ML) and ice-dammed lakes (ID-LL) landscapes were not studied. Since the landscape of ice-dammed lakes origin has diversified relief and is under intensive agricultural use, the aspects of erosion are of great importance. The changes in PSD were studied in 14 soil catenas (toposequences) of eroding soils at the upper slope (US) as well as colluvial soils at the middle (MS) and lower (LS) slopes and in the depressions (D). The PSD of the fine fractions (<2 mm) was analysed according to the hydrometer method. In order to describe the effect of agricultural use on the variability of PSD in soil surface horizons, sedimentological and granulometric indices were calculated. In the studied moraine landscape, the content of coarse silt fraction was increasing in the catenal sequence from 9.7% in the US to 17.7% in the D. Similar relationships were revealed for the fine silt content. Significant differences were found between the average contents of coarse and fine silt fractions at the US as well as the LS and the D. However, such a relation was not found in the soil catena in the ice-dammed lake landscape. Eroded and colluvial soil materials were very poorly sorted with a standard deviation index of 2.65–3.69. Humus horizons of analysed soils had very fine, fine skewed PSD, mesokurtic and platykurtic distribution (ML), symmetrical, fine skewed and platykurtic distribution (I-DLL). The cluster analysis enabled the separation of two groups of soils: one group in the moraine landscape and the other in the ice-dammed lakes landscape. The PSD in studied soils was similar only among the soils within one type of landscape.

Reservoirs facilitate colonization of river catchments by a native invasive fish through provision of pelagic larval rearing habitat

Dams on rivers are known to facilitate the colonisation and spread of aquatic alien and native invasive species, but the actual mechanisms involved are poorly understood. Since the construction of the Solina Dam on the upper San River system in Poland, European perch (Perca fluviatilis) have expanded their distribution into the headwaters of this river system, becoming a native invader. In this study, we assessed the spread of perch in detail over time upstream of the Solina Reservoir, and used otolith trace element microchemistry to determine the spawning and larval rearing locations of perch in the catchment upstream of the dam. Extensive sampling over several years across the catchment upstream of the Solina Reservoir confirmed the widespread occurrence of perch into the headwaters of the tributary river systems, with smaller size classes dominating locations closer to the Solina Reservoir. Despite perch being widely distributed upstream of the Solina Reservoir, otolith microchemical analysis indicated the populations from various reservoir tributaries mostly shared the same spawning and larval rearing habitat, most likely the Solina Reservoir. Our results suggest that reservoirs can facilitate the colonisation of river systems by providing a critical habitat element that would be otherwise missing from riverine landscapes, i.e., an extensive and productive pelagic larval rearing environment. This research shows that the impacts of large dams can extend many kilometers upstream from the river reaches directly affected by the resulting impoundment.

Potential approaches to establishing harmonious river‐human relationships

AbstractThis paper responds to a call to address the development and building of river‐human relationships in the twenty‐first century. Many literatures have identified the historical instrumental exploitation of natural resources underpinning urbanisation and the economic development leading to wide‐spread degradation of environments including rivers. Clearly such relationships can no longer be considered as appropriate in the twenty‐first century. This paper intends to present a conceptual rethink to address the following question: Are there potential approaches by which humans can develop harmonious coexistent relationships with riverine landscapes and associated ecosystems? In answering this question, this paper draws on ideas from new materialism thinking. New materialism offers useful guidance in understanding human‐river relationships in which river landscapes are not static backgrounds to the performance of the social. River systems and environments are active participants influencing and shaping social performances through multiple and diverse interconnected and complex human‐nonhuman relationships and co‐productive partnerships. It is concluded that new materialist perspectives provide important guidance for developing harmonious river‐human relationships. De‐centring the human as the dominant actor in relations with river landscapes and acknowledging rivers as key actors within river‐human relationships may enhance the building of harmonious coexistent and mutually beneficial relationships in the twenty‐first century. It is further concluded the Nature Futures Framework (NFF) and Human‐River Encounter Sites (HRES) frameworks in their capacity to accommodate new materialist thinking provide an opportunity for further exploration and examination of the possibilities for building harmonious coexistent river‐human relationships.

Effect of Different Land Use Types on the Taxonomic and Functional Diversity of Macroinvertebrates in an Urban Area of Northern China

The urbanization of riverine landscapes is an increasing threat to river ecosystems. However, it is unclear which metrics can best assess the response of macroinvertebrates to the conversion of forested lands to urban and agricultural lands. The main goal of this study is to examine whether trait-based approaches are more sensitive than taxonomic approaches in distinguishing macroinvertebrate responses to different land use types in a highly urbanized area of northern China. Results based on 14 environmental variables showed a significant difference across a human-induced environmental gradient. The results showed that no significant differences were observed in terms of taxonomic diversity indices between the different land use types. Functional evenness (FEve) and Rao’s quadratic entropy decreased with the increase in urban area caused by the intensification of human activity, demonstrating that functional diversity is more sensitive than taxonomic diversity in discriminating between different land use types. In addition, the results based on RLQ (physical–chemical variables (R), macroinvertebrate taxa (L), and species traits (Q)) and fourth-corner analyses indicated that the trait states of bi- or multivoltine, high dispersal capacity, and not-streamlined body shape were much higher in the agricultural area and positively related to farmland percentage. Taxa with large body size were dominant in urban areas and were positively correlated with EC. Overall, the observed responses of traits to environmental variables suggest that trait-based approaches should be incorporated into land use management for river restoration.

Arduino data loggers: A helping hand in physical geography

AbstractMicrocontrollers such as Arduino have been increasingly used by researchers to create and customise their own tools. In geography, microcontrollers are frequently used to design data loggers for monitoring purposes. We reviewed the use of Arduino in physical geography to unravel the opportunities and challenges of using off‐the‐shelf tools in research. We conducted a literature review, putting the retrieved information in perspective with our experimental work in mountainous and riverine landscapes in Chile and Peru. We show that the low cost and versatility of Do It Yourself (DIY) data loggers open research opportunities, extending the range of application of their expensive commercial counterparts. The possibility of connecting Arduino to a wide range of sensors, actuators, and wireless communication devices has helped to monitor rivers, glaciers, lakes, ice‐waves, caves, and landslides, improving the temporal and spatial resolution of data collected in critical environments. Low‐cost sensors have been extensively compared against expensive alternatives with good results, although they require thorough testing before field deployment due to the common existence of defective equipment. Building research equipment has several challenges. DIY data loggers might not be unconditionally accepted by environmental agencies, partially restricting their use to educational and research purposes. Failures in data loggers can be difficult to track, since they might be related to coding, electronic assemblage, or inadequate housing to withstand outdoor use. Yet, Arduino‐based data loggers have helped scientists around the world in different stages of their career, especially in scarcely funded research endeavours. Arduino has boosted creativity and resourcefulness, paving the way for innovative monitoring strategies in physical geography.

Enhancing the functionality of environmental flows through an understanding of biophysical processes in the riverine landscape

While water resource managers and river scientists recognize the inherent interconnections among hydrology, river structure, biophysical processes and ecological patterns, management of environmental flows still pays insufficient attention to the ecological and geomorphological functionality of particular aspects of the flow regime. Implementation of more natural flow regimes has improved habitat conditions for native species in many moderately impaired rivers but mimicking a natural flow regime in heavily modified riverine landscapes cannot be expected to yield successful ecological outcomes unless such flows trigger functional processes. For example, the restoration of peak flows may not regenerate habitats if the river is starved of sediment or if the river channel is highly confined. High biodiversity is supported when variable flow regimes interact with spatially variable (heterogeneous) river channel and floodplain forms. In contrast, as rivers become homogeneous, biodiversity decreases when these dynamic spatiotemporal interactions are limited by flow alterations, blocked by channel levees, or perturbed by sediment deficit or surplus. Thus, the design of a more natural environmental flow regime without consideration of the implications for sediment transport and implicit recognition of channel–floodplain geomorphology is likely to have limited success in river management and restoration. To enhance the functionality of environmental flows, considerations of physical, biogeochemical, and ecological processes and the inherent heterogeneity of the riverine landscape must be included. A Functional Flows approach enhances the benefits from limited environmental flow allocations by focusing on the ecological and geomorphological functionality of particular aspects of the flow regime, considering geomorphic context, and emphasizing spatiotemporal diversity at key locations in the riverscape, such as adjacent floodplains or tributary junctions. In this paper, we outline and illustrate the concept of Functional Flows using a flow-chain model and provide two case study examples from Australia and the United States, where improvements in channel habitat and reconnection with the floodplain help to achieve the desired functionality of environmental flows.

Element transport in the Taz River, western Siberia

The riverine export fluxes of dissolved carbon, nutrient and metals from the land to the Arctic Ocean are fairly well quantified for five large Arctic rivers but remain virtually unknown for mid-sized Eurasian rivers, notably those draining through the permafrost zone. Because such rivers can most rapidly respond to on-going climate warming and permafrost thaw in the Arctic, their current hydrochemical composition and elemental yields are badly needed for judging the level of changes in the very near future. Towards quantifying the annual export fluxes and assessing the mechanisms of seasonal variability of river solutes, we monitored the pristine subarctic Taz River (Swatershed = 150,000 km2), which drains through boreal forest and peatlands in the discontinuous and continuous permafrost zone, on a weekly to monthly basis over a 3 year period.Based on seasonal pattern of riverine solutes (< 0.45 μm) and their dependence on discharge, 3 groups of elements were distinguished. These groups of solutes were consistent with several main sources of elements in the main stem of the Taz River such as deep groundwater, riparian zone and floodplain lake sediments, plant litter, mineral soil water, and peatwater from the peatlands. The 1st group was represented by dissolved inorganic carbon (DIC), specific conductivity, and some nutrients (NO3, NH4, Ntot and Si) and soluble elements that originated from groundwater and deep soil mineral horizons (Cl, SO4, Li, B, Na, Mg, Ca, Si, K, Rb, Mn, Co, Sr, Mo, Cs, Ba and W) and showed maximal concentration at the end of winter, before the spring ice-off. This group showed negative correlation to discharge. The 2nd group included dissolved organic carbon (DOC), low-mobile hydrolysates and organically-complexed trace metals (Al, Be, V, Ni, Y, Se, Zr, Nb, REEs, Hf, Pb and Th) which demonstrated maximal concentrations during the spring flood and autumn high flow and minimal values during winter. The concentration of these elements generally increased with water discharge, presumably due to their mobilization in the form of organic and organo-mineral colloids by surface flow through forest litter and via suprapermafrost flow from peatlands. And lastly, the 3rd group of solutes included macronutrients (P, N), Fe, Ti, Cr, Ga, Ge, As, Pb, and U which exhibited features of first two groups and originated from both surface and underground sources. This group showed the strong impact of autochthonous biotic processes in the river channel and soils of the watershed (nutrients, Si).Similar to other Arctic rivers, the spring flood (May and June) provided 30–40% of annual export for DOC, macronutrients and most major and minor solutes. The exceptions are DIC, Si, Ca, Mg and Fe which exhibited essential (30–40%) export during winter baseflow, whereas >70% of annual Mn flux occurred in winter. A number of elements present in the snowpack exhibited sizable (> 45%) export during spring flood (Zn, Cu, Pb, Cd, Sb and Cs). The 3 years mean export fluxes (yields) of dissolved components were comparable to or 30–50% lower than those of other large and medium sized Arctic rivers. This was due mostly to a lack of fresh unaltered rocks and a dominance of peatlands within the Taz River watershed. Elevated concentrations of redox-sensitive micro-nutrients (such as Fe and Mn) occurring during winter baseflow can be linked to disproportionally large floodplain zone of this river which can act, especially in the river's lower reaches, as a stratified lake thereby releasing high amounts of redox-sensitive elements from the sediments. The role of suboxic zones in the Arctic boreal riverine landscape may be more important than previously thought, and may allow explaining anomalously high concentrations of some metals (i.e., Mn) reported in Arctic Ocean surface waters. It is anticipated that climate warming in the region may increase the contribution of winter flow and enhance the export of soluble elements and some nutrients (such as Si, Mn and Co).

Fisheries as ecosystem services: A case study of the Cauvery river basin, India

Habitat alterations and fragmentation caused by anthropogenic modifications of the riverine landscape have affected fish biodiversity by reducing the number of fish species. Fish are a major element of the aquatic environment, and they play an important role in maintaining ecosystem resilience. However, an incomplete understanding of links between river ecosystem functions and processes with fisheries is one of the major reasons for the alarming rate of decline of fish species. Recognizing the ecosystem services generated by fish populations is essential and is one step toward comprehensive, ecosystem-based management of riverine fisheries. Therefore, this paper is motivated by the need to explore the dimensions of fisheries as an ecosystem service. The data was collected from primary field observations and checklist-based key informant interviews at the seventeen fishing sites selected across an 800 km river stretch of the river. In addition, two focused group discussions with fishers at two sampling sites were held to provide first-hand knowledge of ecosystem services generated by fisheries. At first, the role of fisheries in generating ecosystem services for riverine ecosystem functioning and human demands is outlined using the Millennium Ecosystem Assessment approach. Then, the findings of a survey carried out from the headwaters to the delta of the Cauvery river are presented detailing the fisheries provisioning services, livelihoods, and other ecosystem services. The findings showed that the provisioning and cultural services are highly represented among the four categories of ecosystem services identified by the Millennium Ecosystem Assessment. However, in the literature reviewed, supporting, and regulating services are not well-represented. Based on these findings, the applicability of the ecosystem service concept can be elaborated to inform researchers and policymakers to enhance conservation efforts for fisheries.

Habitat and river riparian assessment in the Hyrcanian Forest Ecoregion in Iran: providing basic information for the river management andrehabilitation.

The Hyrcanian Forest holds broad leaf forest remnants dating back to the early Cenozoic Era, which once covered a vast area of the North Temperate Zone. Today, many rivers within this region have been altered by human activities and urgently need rehabilitation. In this regard, 35 wadeable rivers including 14 reference and impacted sites were investigated to determine how different human pressures altered riverine landscapes and habitats. Hence, five common human pressures (agriculture, urbanization, aquaculture, dams, aggregate mining) were identified, then the riverine landscape and habitat condition of each site were assessed. At each site, 17 aquatic, riparian, and terrestrial features, including abiotic and biotic substrate types, were investigated. The number and ratio of pressure-influenced channel features and substrate types differed from those in reference sites. Reference sites were dominated by microlithal, mesolithal, and macrolithal abiotic substrates and large wood, algae, and coarse particulate organic matter biotic substrates. Urbanized sites were most altered and dominated by single channels, steep unvegetated riprap banks, and algae substrate. The results provide valuable information for managers and decision-makers to restore riverine ecosystems considering the impaired parameters resulting from human pressures.

From Works of the Cartographic Heritage to the Digital 3D Model and Presentation of the Riverine Landscape

From Works of the Cartographic Heritage to the Digital 3D Model and Presentation of the Riverine Landscape

A novel knowledge base method in Riparian Buffer Zone (RBZ) delineation with remote sensing imagery

The importance of Riparian Buffer Zones (RBZs) on riverine landscapes has recently received growing attention, which has led to studying, mapping, and monitoring RBZs areas. Additionally, several studies have examined their influence on water quality, vegetation cover, wild life, sediment, and pollution sources. The Riparian Buffer Zones, which are terrestrial areas located between fluvial water bodies and land, provide several ecosystem services and have a rich biodiversity. The present study aimed to identify and monitor the Riparian Buffer Zones in the Gorganroud basin which is located in the north of Iran and south eastern side of the Caspian Sea. This region is one of the largest basins and one of the most precious regions in Iran due to its humid climate and famous forests. RBZs were monitored in four corners of the basin within three selected sub-basins. Land-use map of the Riparian Buffer Zones was extracted in each part within dense vegetation, low-density vegetation, and water, and the area and percentage of each Buffer class were derived for each sub-basin. Two indexes of NDVI and NDWI were calculated and applied for identifying water and green cover pixels of the region and their dispersion. These two indicators helped extract an accurate map of the buffer zones. The results showed that the water buffer area in the north part was significant in comparison with the southern and eastern parts, which could be due to due to more rice fields. Furthermore, low-density vegetation was higher in the south since it is a mountainous area. Further, dense vegetation was high in the center of the watershed due to forests, which was confirmed by the NDVI index.

Geomorphic response of outburst floods: Insight from numerical simulations and observations––The 2018 Baige outburst flood in the upper Yangtze River

Outburst floods related to glacial or landslide damming are a major agent of geomorphic change in mountain rivers. Although the evidence between outburst flooding and riverine landscapes has been gradually recognized, the lack of hydraulics to the extent that there has still not been quantified on the relationship of how the amount and spatial distribution of these changes relate quantitatively to the hydraulic conditions and durations of these catastrophic events. This study combined remote and field observations of the 2018 Baige outburst flood with two-dimensional numerical simulation using the diffusive wave equation. By feeding the measured dam-breach hydrograph and comparing three different Manning coefficients in numerical experiments, the simulation results show that when n = 0.055, the time of peak flow was only 0.5 h different from that indicated by measured data in Yebatan, 54 km downstream of the Baige landslide dam. Under high shear stress over several hours at sustained ~20 m water depth, lateral erosion caused by these outburst floods contributed to the adjacent landslide, which was activated in association with intermittent water velocity waves of approximately 17 m/s. Sustained high stream power (>50 kW m2) from the outburst flood eroded slope toes and accelerated slippage of six slopes. Combining simulation and observations, we also developed a physical model related to hillslope instability caused by high hydrodynamic erosion of riverbanks generated by flow waves lasting several hours, which explained the hydrodynamic response of the outburst flood to the canyon geomorphology. Furthermore, we suggest that the pattern of channel widening erosion and deposition is governed by the variation in shear stress and Froude number as the high-energy flood flows from a wide channel into a narrow river valley. Our findings highlight that the hydraulics of high-magnitude outburst floods and sediment transport play crucial roles in reshaping canyon geomorphology.

Latitudinal and Altitudinal Gradients of Riverine Landscapes in Andean Rivers

Exact knowledge of the physical structures of different river sections that govern their ecological structure and function is essential for the efficient conservation and management of riverine ecosystems. Eleven Andean river basins (Maipo, Rapel, Mataquito, Maule, Itata, Biobío, Toltén, Valdivia, Bueno and Puelo) comprise large scale latitudinal and altitudinal gradients and accommodate 71% of the Chilean population that strongly depend on their ecosystem services. Here, based on 16 hydrogeomorphic variables (on basin, valley and channel scales), we assessed the riverine landscapes (Functional Process Zones; FPZs) of these river basins using a top-down multivariate statistical approach. Two steep valley and downstream slope FPZs, three sinuous FPZs and two braided FPZs emerged in 8906 river sections. The proportion of the occurrence of FPZs was characterised by a clear latitudinal pattern which is strongly related to the proportions of each river basin within the large morphostructural units of Chile. As such, the proportion of each river basin within the Andes Cordillera, Central Valley and Coastal Cordillera is a strong driver of the fluvial geomorphology and, thus, of the FPZs’ arrangement in each river network. FPZ classification captured geomorphic diversity that coincided with the latitudinal and altitudinal gradients of Chilean Andean river basins strongly related to the hydrological characteristics of the assessed river basins and large scale spatial distribution of fish fauna endemism. As such, the identified large geomorphic units (FPZs) that are strongly tied up with hydrology and ecology hierarchies of riverine landscape provide robust operational tools that can be instrumental for river ecosystem monitoring and management at a basin scale.

Urbanizing the Eternal City: How did the ancient Romans transform and adapt to Rome’s riverine landscape?

This case study considers the trajectory of Ancient Rome’s urban development in its riverine environment. Recent geoarchaeological investigations in Rome’s river valley have shed light on the pre-urban setting and landscape changes that occurred alongside urbanization. With these new discoveries and a rich corpus of archaeological and historical evidence, Rome offers one of the longest records available for exploring how rivers impact cities and cities impact rivers.In order to build in their flood-prone lowlands in the mid-1st millennium BCE, the inhabitants of Rome engaged in large-scale landscape modification projects and flood mitigation measures. Urbanization at Rome, however, triggered fresh ecological challenges, including rapid sedimentation and escalating floods. The inhabitants of Rome responded to their volatile river with a range of adaptive strategies. Over the centuries, they continued to mitigate the effects of overbank flooding through the use of strategic urban planning, land reclamation, flood-resistant architecture, and bureaucratic oversight of the riverine landscape. It is noteworthy that, despite having the capabilities, the ancient Romans chose not to enact large-scale engineering projects to prevent floods altogether. The so-called Eternal City, therefore, should be seen as a resilient city—one that persevered in the face of dynamic ecological conditions and recurrent inundations.This article emphasizes the value of historical applications for modern sustainability studies: the past offers both empirical evidence and a vibrant perspective for conceptualizing the complexities of human-environment interactions over many centuries. The story of Rome’s relationship with its river ultimately underscores the eternal co-evolution of society and the environment.

Temporal and spatial patterns in the shifting of otter diet to invasive prey after river damming

AbstractRiver damming promotes profound changes in aquatic biodiversity, including the facilitation of biological invasions, with subsequent impacts on native communities. The Eurasian otter (Lutra lutra) is a generalist aquatic predator that often incorporates new prey types when they become available. We studied the short‐ and long‐term effects of river damming on the trophic ecology of the otter across a riverine landscape gradient, from the flooded area to upstream tributaries, focusing on the largest artificial lake of Western Europe. Through the analysis of otter feces (spraints), we describe otter diet composition in 14 sites at different distances from the impounded area in three periods: (i) the pre‐filling phase (i.e., lotic conditions); (ii) the immediate filling phase; and (iii) 16 years after the dam closure. The diet of the otter drastically shifted in the short term, from being dominated by native cyprinids to being mainly composed of invasive species of fish and crayfish. In the long term, the number of invasive species consumed by the otter continued to increase while native fish completely disappeared as prey near the reservoir. Presumably, the construction of the dam generated clear spatial gradients of abundances of native and invasive fish species. These patterns arose in the short term but became accentuated in the long term and were mirrored in otter diet composition. Our results demonstrate the potential of otter diet analyses as a surrogate for the impacts of human alterations on aquatic ecosystems, including those of river damming and the associated facilitation of biological invasions.

Are springs hotspots of benthic invertebrate diversity? Biodiversity and conservation priority of rheocrene springs in the karst landscape

Abstract Springs are perceived by human society as essential sources of drinking water, but on the other hand they represent peculiar and vulnerable ecosystems. They differ from other watercourses in the relatively high stability of their physicochemical conditions. As a result, springs represent ecosystems with an insular character, usually inhabited by specific aquatic communities. Although springs are generally considered species‐rich habitats across the world, they have been outside scientific and conservation interest in the karst mountains of the Western Carpathians. This study, therefore, examined the diversity of spring benthic macroinvertebrates and compared it with that of other watercourses of the Western Carpathian riverine landscape. The results of the study showed that, in contrast to rhithral streams, individual karst springs often had low species richness, and therefore they cannot be considered biodiversity hotspots. However, their metacommunity diversity is characterized by high taxonomic turnover, resulting in high gamma diversity. This means that the individual springs often harbour unique macroinvertebrate communities, so they are worthy of protection. However, the present level of spring habitat protection is insufficient as even springs located in protected areas are often captured as sources of drinking water and hydromorphologically or otherwise disturbed. A simple method to evaluate the spring conservation priority (CP) was developed to find a better trade‐off between their use and protection. It uses the number of Red List, endemic and crenal taxa, as well as the total species richness at each site. Based on this classification method, 16% of the springs studied reached very high CP, 39% high CP, 33% moderate CP and 12% low CP. The proposed management recommendations based on findings of conservation priority of the Western Carpathian karst springs can significantly contribute to their more effective protection and the creation of a legislative framework relating to spring habitat protection in general.

Effective restoration measures in river‐floodplain ecosystems: Lessons learned from the ‘Wilde Mulde’ project

AbstractOver the last 40 years, a growing number of restoration projects have been implemented to improve the ecological conditions of highly degraded rivers and their floodplains. Despite considerable investment in these projects, information is still limited about the effectiveness and the success of such river restoration measures, mainly due to a lack of standardised and interdisciplinary assessment approaches. During the project ‘Wilde Mulde—Restoration of a dynamic riverine landscape in Central Germany’, we implemented hydromorphological restoration measures (installation of large wood, removal of rip‐rap, reconnection of a former river side‐arm) along a lowland river in Central Germany. We carried out intensive scientific monitoring of biodiversity, hydromorphology, ecosystem functions and services, as well as socio‐economic aspects. A Before/After‐Control/Impact (BACI) design was used to identify the spatial and temporal effects of the restoration measures and to distinguish them from changes caused by background variation. For this, we used a comprehensive set of indicators, including abiotic (flow velocity, diversity of riverbed topography, and flow resistance), biological (ecosystem respiration, macroinvertebrates, fish, carabids, vegetation, and birds) and socio‐economic (acceptance and public awareness) indicators as well as the ecosystem service indicator aesthetic quality of the landscape. To meet the inherent challenges of such a large‐scale field experiment, like unpredictable environmental conditions, we used an experimental approach that allowed us to demonstrate a measurable success of the implemented restoration measures. The majority of the abiotic and some of the biological and socio‐economic indicators at the restored sites approached values of a natural reference site while already deviating from values of a nonnatural reference site two years after restoration. In addition to the applied interdisciplinary approach, multiple scales of field investigations and data analyses are essential as key components for evaluating successful river and floodplain restoration projects.

Initial biological development of a newly established side channel at the Lower Rhine

AbstractWithin the EU LIFE‐Nature project ‘River and floodplain revitalisation Emmericher Ward’, three small temporary waters and a former gravel pit were connected by a side channel running parallel to the river Rhine through former groyne fields. The initial status of macrozoobenthos, fish, avifauna, flora, vegetation, and habitats before and their development after implementation of the project's measures were recorded and compared. The monitoring years 2018 and 2019 were exceptionally dry and accompanied by an extremely low runoff in the Rhine and the side channel. These conditions likely affected the development of habitats and species populations in the new side channel. The new side channel showed intensive morphodynamic development and differentiation of its structures. While the more complex vegetation and habitat types appeared as mostly species‐poor initial stages, short‐lived species‐rich pioneer habitats such as annual mud banks in the water exchange area were already established. Two years after the implementation, the benthic invertebrate fauna was still predominantly species‐poor and dominated by neozoans. Occasionally, representatives of the more sensitive EPT fauna (Ephemeroptera, Plecoptera, Trichoptera) were already detected but were, in general, strongly underrepresented in the main stream. Low colonisation potential, nonpermanent flow, and lack of river wood limit the development of the macrozoobenthos community. The relative abundance of rheophilic fish species increased in the project area and high juvenile fish densities proved the function as a nursery habitat. As pioneer species of riverine landscapes, sand martins and little ringed plovers colonised the new structures already in the first year. The initial state of the side channel represented a typical dynamic pioneer habitat pattern of a sandy lowland river, which was almost absent in the Lower Rhine area. The new habitats were quickly colonised by pioneer flora and fauna, but the potential for more demanding and complex communities was restricted by the poor structural and biological states of the Lower Rhine.