Riverine Landscapes Research Articles

Characterization of River Networks: A GIS Approach and Its Applications.

Fluvial geomorphology provides the basis for characterizing complex river networks and evaluating biophysical processes within watersheds. Understanding the spatial organization of morphological features, their influencing processes, and resultant geomorphic diversity in stream networks are important for efficient restoration, river health assessment, and improving our knowledge of the resilience of riverine landscapes. River characterization is a means to determine the biophysical character of river networks but many methods are fraught with pitfalls, such as the use of incorrect variables and limited acknowledgment of the hierarchical organization of rivers. In this paper, a top-down geographic information system-based approach for determining the physical typology of river networks is outlined. A suite of multivariate analyses are used to develop a nomenclature for functional process zones (FPZs) - large tracts of the river network with similar hydro-geomorphological character. Applied to the Little Miami River, Ohio, six distinct FPZs emerged, which had a nonuniform distribution along the river network. Some FPZs repeated downstream; others were rare in terms of total length and number of FPZ segments. The physical structure of the Little Miami River network was analyzed using a series of community metrics. Application of this approach for river monitoring, establishing reference conditions, as well as management of threatened and endangered species and asset trading is highlighted.

Impacts of urban stream pollution: A comparative spatial hedonic study of high‐rise residential buildings in Guangzhou, south China

Urban streams are scarce natural elements in compact cities, and suffer from pollution in the course of city expansion and densification, especially in developing nations like China. They may offer the amenity of a riverscape view, but also the dis‐amenity associated with water pollution. Yet whether and how polluted urban streams affect high‐rise residential property values remain under‐investigated. Based on a total of 315 transaction records of apartment sales in two residential precincts located near two typical urban streams in Guangzhou, south China, this study attempts to assess the impacts of urban river pollution, in terms of view and proximity, at a neighbourhood level. A novel “cube contiguity”, consisting of a three‐dimensional spatial weighting matrix, is developed to incorporate the effect of property height in hedonic price models. Comparison of the spatial hedonic analysis of the two selected residential precincts reveals that views of heavily polluted urban streams fail to command a premium, and the impacts of proximity to urban streams vary considerably in high‐rise, compact urban contexts, when micro‐level landscape variations are carefully represented in hedonic modelling. This could be associated with the hydro‐morphological features and riverine landscape, as well as with homebuyers’ subjective perception of river pollution. Assessing the impacts of urban stream pollution could provide a basis for understanding the negative externalities of urban river pollution, establishing priorities for restoring polluted urban streams, and planning the provision of multi‐functional green‐blue spaces with respect to homebuyers’ demand for environmental amenities in mid‐ and high‐rise housing markets in both developed and developing nations.

New tools, new human niches: The significance of the Dalton adze and the origin of heavy-duty woodworking in the Middle Mississippi Valley of North America

Innovations in tool technology during the early Holocene in the North American midcontinent are related to construction of a new human niche focusing on woodlands, water travel, and improved aquatic and terrestrial resources. Production and use of early Holocene Dalton adzes and other tools from sites and caches exemplify these adaptations. Subsistence remains are not abundant, but microwear and technological analyses of flaked stone tools can be used to infer production of dugout canoes and document trends that reflect new sustainable and resilient lifeways and complex social networks. The functions of tools from Dalton sites and tool caches in Illinois and Arkansas are contrasted with typical Clovis tools. Technological and microwear analyses reveals that the Dalton adze was made and used for heavy-duty woodworking—felling trees and likely for manufacturing dugout canoes. Dalton toolkits are highly formalized, consisting of adzes, scrapers, awls, and points used both as projectiles and knives.Large distinctive Sloan points were exchanged within emerging Dalton social networks. Dalton toolkits, often considered late PaleoIndian, are part of an Early Archaic horizon. New tools helped Dalton groups to create new niches as they settled into new woodland and riverine landscapes and laid the foundation for later Archaic and Woodland socio-economic systems.

Effects of riverine landscape changes on pollination services: A case study on the River Minho, Portugal

Riverine landscapes provide numerous ecosystem services, of which pollination is essential to increase the yield, quality, and stability of crops and the biodiversity of wild flora. Pollinators’ behaviour and their community dynamics are often affected by the spatial distribution of floral and nesting resources at the landscape scale, and are thus sensitive to land-use land-cover (LULC) changes and management practices.The main objective of this study is to understand how changes in riparian vegetation and LULC at River Minho affect pollination services. For this, an approach based on the temporal analysis of historical cartography (1898) and current satellite imagery (2016) was used. We developed a novel Pollination Suitability Index for Riverine Landscapes (PSIRL) using LULC data as a proxy of habitat suitability for insect pollinators. PSIRL scores were derived from expert judgment of the local habitat conditions, floral diversity and field surveys. The PSIRL values obtained for both periods were compared using pairwise T-tests.We detected an overall reduction of the pollination services in the riverine landscape of River Minho from 1898 to 2016. However, at local level we observed gains and losses of pollination suitability as a result of distinct LULC changes. There was a marked decrease in the PSIRL in the most downstream and upstream riverine sections due to generalized conversion of scrublands, broadleaved-forests and heterogeneous agricultural areas to artificial surfaces and managed forests dominated by maritime pine and eucalyptus. However, in the middle section of the river, the area occupied by scrublands, riparian and broadleaved forests increased, resulting in an increase of the foraging resources for insects, and a consequent increase of the PSIRL.This index can be used to monitor and capture changes in the pollination suitability of complex riverine landscapes and support further land and river management decisions. The historical cartography proved to be a valuable source of information to characterize LULC change and hence to assess the evolutionary trajectory of pollination ecosystem services, at global and local level.

Assessing the aesthetic quality of landscapes in Germany

A high landscape aesthetic quality (LAQ) arguably is an important ecosystem service that positively affects humans’ health and well-being. It is strongly appreciated by citizens and provides the backdrop and precondition for many outdoor activities. The objective of this paper is to map and assess the LAQ of landscapes across Germany. We developed and tested a method for a spatially explicit national assessment of LAQ. The method uses landscape diversity, naturalness and uniqueness as established indicators for landscape attractiveness, and applies several landscape metrics as proxies to spatially evaluate and map each of them. The results demonstrate that the LAQ varies substantially across Germany. Areas of high LAQ are located in the German high and many low mountain ranges, in riverine landscapes, and at the German coast and islands, whereas particularly low LAQ scores are found in urban agglomerations and intensively used open agrarian landscapes. The proportional distribution of values shows that most area is covered with mediocre scores, and that areas of extremely high or low scores are rare. The results respond to the EU biodiversity strategy’s request to member states to map and assess ecosystem services, and can usefully inform national and sub-national policy-, plan-, and decision-making.

Morphodynamic effects of riparian vegetation growth after stream restoration

AbstractThe prediction of the morphological evolution of renaturalized streams is important for the success of restoration projects. Riparian vegetation is a key component of the riverine landscape and is therefore essential for the natural rehabilitation of rivers. This complicates the design of morphological interventions, since riparian vegetation is influenced by and influences the river dynamics. Morphodynamic models, useful tools for project planning, should therefore include the interaction between vegetation, water flow and sediment processes. Most restoration projects are carried out in USA and Europe, where rivers are highly intervened and where the climate is temperate and vegetation shows a clear seasonal cycle. Taking into account seasonal variations might therefore be relevant for the prediction of the river morphological adaptation. This study investigates the morphodynamic effects of riparian vegetation on a re‐meandered lowland stream in the Netherlands, the Lunterse Beek. The work includes the analysis of field data covering 5 years and numerical modelling. The results allow assessment of the performance of a modelling tool in predicting the morphological evolution of the stream and the relevance of including the seasonal variations of vegetation in the computations. After the establishment of herbaceous plants on its banks, the Lunterse Beek did not show any further changes in channel alignment. This is here attributed to the stabilizing effects of plant roots together with the small size of the stream. It is expected that the morphological restoration of similarly small streams may result in important initial morphological adaptation followed by negligible changes after full vegetation establishment. Copyright © 2018 John Wiley & Sons, Ltd.

Quantifying biomass production for assessing ecosystem services of riverine landscapes

Society is increasingly in need of renewable resources to replace fossil fuels and to prevent resource depletion. River-floodplain systems are known to provide important societal functions and ecosystem services to mankind, such as production of vegetative biomass. In order to determine the potential of harvesting vegetative riparian biomass, the capacity of river systems to produce such biomass needs to be determined. We developed a method for quantifying the spatiotemporal development of annual biomass production in river floodplains. Vegetation specific growth rates were linked to a landscape classification system (i.e., the Ecotope System for National Waterways). Biomass production was calculated for floodplains along the three Rhine River distributaries (i.e., the rivers Waal, Nederrijn-Lek and IJssel) over a 15year period (1997–2012). During this period several large scale river management measures were undertaken to reduce flood risks and improve the spatial quality of the Rhine River as part of the Room for the River program. Biomass production decreased by 12%–16% from 1997 to 2012 along the three distributaries, which may be a side effect of flood mitigation. Almost 90% of the biomass produced was non-woody (e.g., grass/hay, reed, crops), which decreased along all three river distributaries due to the abandonment of production grasslands and the physical reconstruction of floodplains (e.g., creation of side channels). Woody vegetation, however, showed a slight increase during the 15year period likely owing to vegetation succession from shrubs to softwood forest.

Beyond the Edge: Linking Agricultural Landscapes, Stream Networks, and Best Management Practices.

Despite much research and investment into understanding and managing nutrients across agricultural landscapes, nutrient runoff to freshwater ecosystems is still a major concern. We argue there is currently a disconnect between the management of watershed surfaces (agricultural landscape) and river networks (riverine landscape). These landscapes are commonly managed separately, but there is limited cohesiveness between agricultural landscape-focused research and river science, despite similar end goals. Interdisciplinary research into stream networks that drain agricultural landscapes is expanding but is fraught with problems. Conceptual frameworks are useful tools to order phenomena, reveal patterns and processes, and in interdisciplinary river science, enable the joining of multiple areas of understanding into a single conceptual-empirical structure. We present a framework for the interdisciplinary study and management of agricultural and riverine landscapes. The framework includes components of an ecosystems approach to the study of catchment-stream networks, resilience thinking, and strategic adaptive management. Application of the framework is illustrated through a study of the Fox Basin in Wisconsin, USA. To fully realize the goal of nutrient reduction in the basin, we suggest that greater emphasis is needed on where best management practices (BMPs) are used within the spatial context of the combined watershed-stream network system, including BMPs within the river channel. Targeted placement of BMPs throughout the riverine landscape would increase the overall buffering capacity of the system to nutrient runoff and thus its resilience to current and future disturbances.

The influence of land use in a highly modified catchment: Investigating the importance of scale in riverine health assessment

Riverine landscapes are studied at varying scales, investigating the complex cause-effect pathways between rivers and their physical, chemical and biological attributes. Policy development, management and planning are often formulated and applied at the regional or catchment scale, however the ecological evidence required to inform at this scale is typically collected from the much smaller scale. This research was aimed at determining if patterns in diatom and macroinvertebrate community composition can be attributed to a specific/single land use in a catchment with multiple land uses. The impacts of forest, macadamia, grazing, sugar cane and urban land uses in the Richmond River Catchment of Northern NSW, Australia were investigated at 20 micro-catchment scale sites. A total of 124 diatom species from 43 genera, along with 92 families and three sub-families of macroinvertebrates, were collected and used to calculate the Richmond River Diatom Index (RRDI), AUSRIVAS and SIGNAL2 scores. Statistical analyses showed distinct groupings of land use categories providing evidence of cause-effect pathways attributed to individual land uses. The RRDI, AUSRIVAS and SIGNAL2 scores all showed distinctions between land use categories, though they were clearer in the RRDI. The RRDI indicated that the grazing sites had the poorest health of the land use categories, followed by sugar cane and urban while the macadamia and forest sites were relatively healthy. Signal 2 scores showed similar trends to the RRDI, while the AURIVAS scores did not present clear trends, particularly in the edge habitat of macadamia land use sites. The results indicated that riparian vegetation and instream habitat play an important role in attenuating inputs and that rehabilitation efforts could potentially improve water quality at a micro-catchment scale and subsequently, result in river health improvement at the catchment scale. The research collected at this micro-catchment scale presents new evidence that further informs and affects decisions made at the catchment scale, where policy and planning is developed and implemented.

Associations between riverine landscape patches and internal and external environmental determinants are scale dependent: evidence from the Scioto River, USA

Associations between riverine landscape patches and internal and external environmental determinants are scale dependent: evidence from the Scioto River, USA

Mapping the temporary and perennial character of whole river networks

AbstractKnowledge of the spatial distribution of temporary and perennial river channels in a whole catchment is important for effective integrated basin management and river biodiversity conservation. However, this information is usually not available or is incomplete. In this study, we present a statistically based methodology to classify river segments from a whole river network (Deva‐Cares catchment, Northern Spain) as temporary or perennial. This method is based on an a priori classification of a subset of river segments as temporary or perennial, using field surveys and aerial images, and then running Random Forest models to predict classification membership for the rest of the river network. The independent variables and the river network were derived following a computer‐based geospatial simulation of riverine landscapes. The model results show high values of overall accuracy, sensitivity, and specificity for the evaluation of the fitted model to the training and testing data set (≥0.9). The most important independent variables were catchment area, area occupied by broadleaf forest, minimum monthly precipitation in August, and average catchment elevation. The final map shows 7525 temporary river segments (1012.5 km) and 3731 perennial river segments (662.5 km). A subsequent validation of the mapping results using River Habitat Survey data and expert knowledge supported the validity of the proposed maps. We conclude that the proposed methodology is a valid method for mapping the limits of flow permanence that could substantially increase our understanding of the spatial links between terrestrial and aquatic interfaces, improving the research, management, and conservation of river biodiversity and functioning.

A Dendrogeomorphological Study of the Local Effect of Climate Change

The climatic and environmental conditions of Patagonia changed substantially after 1850 and after the mid-1970s decade. The impact of these changes is being observed in the new configuration of rivers and their riverine vegetation. The objective of this work is to integrate dendrogeomorphological techniques to the mapping and modeling of the recent distribution of vegetation of the riverine landscape, as an indicator of the local effect of climate change.The hydrological regime and the evolution of riparian vegetation at the confluence of the Cuyin Manzano and Traful Rivers were synchronized using the data obtained from 34 samples of plots of 6x6 meters. The plots were adjusted to the pixel resolution of two SPOT 7 satellite images (flood and dryness), concentric to an area of 18x18 meters, in order to validate a supervised classification of vegetation, belonging to different fluvial geoforms. In the plots with woody vegetation two trees corresponding to one or two age classes characteristic of the stands were drilled. The results indicate that, in agreement with global and Patagonia climate change estimates, there is a slight tendency of change in the flood and drought regime, with decreases in mean annual minimum flows and a period of drought in the last six years. The most outstanding result of our study indicates that the change of the hydrological regime implies a slight reduction of the average minimum flows, without this entailing a modification of the regime of flood pulses that in some cases are very extreme. This situation has a marked incidence in the fact that the woody vegetation colonizes new substrates and emerged landforms, while it is affected by frequent and intense flood events, with a change of the compositions and distribution of the vegetation.

Potential interaction between transport and stream networks over the lowland rivers in Eastern India

Extension of transport networks supports good accessibility and associated with the development of a region. However, transport lines have fragmented the regional landscape and disturbed the natural interplay between rivers and their floodplains. Spatial analysis using multiple buffers provides information about the potential interaction between road and stream networks and their impact on channel morphology of a small watershed in the Lower Gangetic Plain. Present study is tried to understand the lateral and longitudinal disconnection in headwater stream by rural roads with the integration of geoinformatics and field survey. Significant (p < 0.001) growth of total road length and number of road-stream crossing in the last five decades (1970s–2010s) contribute to making longitudinal and lateral disconnection in the fluvial system of Kunur River Basin. Channel geometry from ten road-stream crossings shows significant (p = 0.01) differences between upstream and downstream of crossing structure and created problems like downstream scouring, increased drop height at outlet, formation of stable bars, severe bank erosion, and make barriers for river biota. The hydro-geomorphic processes are also adversely affected due to lateral disconnection and input of fine to coarse sediments from the river side growth of unpaved road (1922%). Limited streamside development, delineation of stream corridor, regular monitoring and engineering efficiency for the construction of road and road-stream crossing might be effective in managing river geomorphology and riverine landscape.

Physical heterogeneity and aquatic community function in river networks: A case study from the Kanawha River Basin, USA

The geomorphological character of a river network provides the template upon which evolution acts to create unique biological communities. Deciphering commonly observed patterns and processes within riverine landscapes resulting from the interplay between physical and biological components is a central tenet for the interdisciplinary field of river science. Relationships between the physical heterogeneity and food web character of functional process zones (FPZs) – large tracts of river with a similar geomorphic character –in the Kanawha River (West Virginia, USA) are examined in this study. Food web character was measured as food chain length (FCL), which reflects ecological community structure and ecosystem function. Our results show that the same basal resources were present throughout the Kanawha River but that their assimilation into the aquatic food web by primary consumers differed between FPZs. Differences in the trophic position of higher consumers (fish) were also recorded between FPZs. Overall, the morphological heterogeneity and heterogeneity of the river bed sediment of FPZs were significantly correlated with FCL. Specifically, FCL increases with greater FPZ physical heterogeneity. The result of this study does not support the current paradigm that ecosystem size is the primary determinant of food web character in river ecosystems.

Crack willow changing riverine landscapes in Patagonia

AbstractIn Patagonia (Argentina) in recent decades, the exotic species and hybrids of Salix alba–Salix fragilis complex has spread over wide areas along watercourses, taking advantage of it is sexually and vegetatively propagation. It outcompetes with native vegetation, facilitated by stochastic events related to large floods of long‐lasting duration higher than the average maximum of 186 m3/s for more than a day. We analysed the exotic willow's increase along the braiding Azul River, and the hydrological regime between 1966 and 2012. We evaluated the links between regime and tree density over time using dendrochronological data. Results showed an increase of the forest's cover from 2.1% to 70.8% over the last 46 years. The densities of exotic willows grew exponentially between 1966 and 1973, during a period which was free of higher floods. The initial native populations declined as willow's population increased. Up to 1973, there was an increase in the native populations too. Then from 1974 on, the willow showed a gradual growth coupled with a decline in the native trees. Up to 1977, the willow expansion could be linked to an extreme flood that reached 392 m3/s (210.75%) greater than the average of the maximum flows). We concluded that plant succession in the Azul River follows a “Red Queen” effect whereby the exotic willow and native trees repeatedly reorganized the system after pulses and periods of extreme flooding events.

Analysing stakeholders\u2019 perceptions of wolf, lynx and fox in a Dutch riverine area

In the last decades, populations of large carnivores have been making a spectacular return, especially in the USA and Western Europe. These population recoveries result partially from protective legislation and reintroduction programs, but possibly also from land use changes and from large carnivores adapting to human environments. Although public support for large carnivore protection seems to be growing, some stakeholders still have a negative perception of large carnivores because of their alleged negative impacts on livestock and humans. Perceptions of large carnivores are partly determined by underlying visions of nature which differ between stakeholder groups. We therefore examined the relationship between different stakeholder groups’ perceptions of nature and the presence of the fox (Vulpes vulpes), and the possible establishment of the wolf (Canis lupus) and lynx (Lynx lynx) in a Dutch riverine landscape. Stakeholder groups comprised the general public, farmers, scientists and nature conservationists. Although perceptions of large carnivores differed significantly across the stakeholder groups, public support for large carnivores was generally higher than expected. Farmers show the most negative perception, especially regarding the wolf and lynx. This is related to their vision of nature, which is more strongly aligned with mastery over nature compared to other stakeholder groups. Scientists, prominent adherers of stewardship of nature, appear to have the most positive perception of large carnivores. Despite these differences in visions of nature, respondents generally adhere to the stewardship of nature relationship. This could be a good starting point to find common ground when disputes arise over large carnivores.

Do Alluvial Sand Dunes Create Energetic Refugia for Benthic Fishes? An Experimental Test with the Endangered Pallid Sturgeon

AbstractRiver modifications have altered critical habitats for fishes at a variety of spatial scales and caused global declines of many fluvial species. At small spatial scales (&lt;1 m2), alluvial sand dunes, a ubiquitous habitat in highly modified rivers, are thought to provide energetic relief for benthic fishes in energetically costly riverine landscapes created by water flow. However, use of alluvial dune habitat is not well understood, and it is unclear whether dunes provide refuge that effectively reduces energetic costs. We designed a scale‐relevant experiment to examine the energetic responses associated with sand dune habitat in rivers. We tested whether the US federally endangered pallid sturgeon (Scaphirhynchus albus), a benthic fish commonly associated with sand dunes, experienced reduced energetic costs with different configurations of simulated sand dune habitat. We quantified mass specific oxygen consumption (MO2; mg O2 kg−1 h−1) using intermittent flow‐through respirometry for age‐0 sturgeon (140–170 mm) in front of a sand dune, behind a sand dune and in the absence of a sand dune at two velocities (25 and 50 cm s−1) commonly observed in field studies of sturgeon habitat use. Sturgeon displayed distinct station holding behaviours for each habitat configuration. Dune location did not affect energy expenditure, but sturgeon MO2 was on average 16–20% higher in the absence of a sand dune depending on dune configuration. MO2 was on average 14% higher at 50 cm s−1 compared with 25 cm s−1. Our results provide a potential mechanism for over two decades of research on why sturgeon and other benthic fishes exhibit selection for sand dune habitat in large rivers. Fishes that select main channel habitats may depend on energetic relief provided by sand dunes, especially when other forms of structure are not available. For this reason, alluvial sand dune habitat may be important to the persistence of benthic fishes in high flow environments. Copyright © 2017 John Wiley &amp; Sons, Ltd.

Determination of the Geogenic Metal Background in Surface Water: Benchmarking Methodology for the Rivers of Saxony-Anhalt, Germany

Geogenic concentrations are defined as those concentrations that represent the natural background without any anthropogenic influence. The paper describes a statistical method for determining geogenic metal concentrations in rivers based on the concept of “aggregated riverine landscapes” (ARLs), which applies to all rivers in the Federal State of Saxony-Anhalt (Germany). The methodology includes the pre-selection of existing data by eliminating all sampling locations from the database which have anthropogenic influence, the GIS-based allocation of the sampling locations with respect to the respective ARL being the evaluation units, and the assessment of the geogenic background by statistical calculation of the 90th percentile. After validation of the methodology, the existing database was complemented by additional measurements for regions with data gaps. About 85,000 records of water samples, 1400 records of sediment samples, and 920 records of suspended particulate samples were used for the determination of the geogenic metal concentrations in the rivers of Saxony-Anhalt. The investigation included the parameters Al, Ag, As, B, Ba, Be, Cd, Co, Cr, Cu, Fe, Mn, Mo, Ni, Pb, Se, Ti, U, V, and Zn. The investigation results offer the determination of regions with increased background levels for certain metals or metalloids in Saxony-Anhalt.

Evaluating riverine hydrokinetic turbine operations relative to the spatial ecology of wild fishes

ABSTRACTHydrokinetic turbines (HTs) are being proposed for placement in riverine landscapes around the globe. Here, we implanted 40 adult lake sturgeon and 40 adult walleye with acoustic telemetry transmitters to monitor their lateral and vertical space use at the Canadian Hydrokinetic Turbine Testing Centre (CHTTC) located in the Seven Sisters Generating station (GS) tailrace on the Winnipeg River, Manitoba. Specifically, we tested whether fish behaviour was influenced by the operation of HTs relative to control periods, and estimate the threat of HTs towards lake sturgeon and walleye across seasons. The behaviour and habitat use of both species was not influenced by HT operations. Greater numbers of walleye were present when the discharge rate was ≥ 950 m3s–1, which is ≥ 77 m3s–1 greater than the average discharge rate (873 m3s–1) measured during the study period. Given the patterns of seasonal residency, movement, and depth use, lake sturgeon appeared more prone to interacting with HTs during spring and early summer months (i.e. May and June), whereas risk to walleye would be highest throughout the summer and autumn months. In the vicinity of the acoustic receivers, available habitat (areas with large boulders, and transitions between swift flow in the channel and slacker water near the shoreline) was used significantly more often by walleye than lake sturgeon. Lake sturgeon utilized similar depths where HTs would be installed (i.e. ≥ 6.5 m), while walleye commonly occupied shallower depths at the HT testing centre making the former more susceptible to interactions with substrate-HT's. Collectively, these are some of the first field-based results on fish behaviour and ecology while a riverine-HT is in operation. The findings present useful information to help guide best practices for commercial scale HT operations within river systems where lake sturgeon and walleye reside.

Productivity and Connectivity in Tropical Riverscapes of Northern Australia: Ecological Insights for Management

Flow regimes are fundamental to sustaining ecological characteristics of rivers worldwide, including their associated floodplains. Recent advances in understanding tropical river–floodplain ecosystems suggest that a small set of basic ecological concepts underpins their biophysical characteristics, especially the high levels of productivity, biodiversity and natural resilience. The concepts relate to (1) river-specific flow patterns, (2) processes ‘fuelled’ by a complex of locally generated carbon and nutrients seasonally mixed with carbon and nutrients from floodplains and catchments, (3) seasonal movements of biota facilitated by flood regimes, (4) food webs and overall productivity sustained by hydrological connectivity, (5) fires in the wet/dry tropical floodplains and riparian zones being major consumers of carbon and a key factor in the subsequent redistribution of nutrients, and (6) river–floodplains having inherent resilience to natural variability but only limited resilience to artificial modifications. Understanding these concepts is particularly timely in anticipating the effects of impending development that may affect tropical river–floodplains at the global scale. Australia, a region encompassing some of the last relatively undisturbed tropical riverine landscapes in the world, provides a valuable case study for understanding the productivity, diversity and resilience of tropical river–floodplain systems. However, significant knowledge gaps remain. Despite substantial recent advances in understanding, present knowledge of these highly complex tropical rivers is insufficient to predict many ecological responses to either human-generated or climate-related changes. The major research challenges identified herein (for example, those related to food web structure, nutrient transfers, productivity, connectivity and resilience), if accomplished in the next decade, will offer substantial insights toward assessing and managing ecological changes associated with human alterations to rivers and their catchments.