Article

Mapping habitat indices across river networks using spatial statistical modelling of River Habitat Survey data

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Abstract

Freshwater ecosystems are declining faster than their terrestrial and marine counterparts because of physical pressures on habitats. European legislation requires member states to achieve ecological targets through the effective management of freshwater habitats. Maps of habitats across river networks would help diagnose environmental problems and plan for the delivery of improvement work. Existing habitat mapping methods are generally time consuming, require experts and are expensive to implement. Surveys based on sampling are cheaper but provide patchy representations of habitat distribution. In this study, we present a method for mapping habitat indices across networks using semi-quantitative data and a geostatistical technique called regression kriging. The method consists of the derivation of habitat indices using multivariate statistical techniques that are regressed on map-based covariates such as altitude, slope and geology. Regression kriging combines the Generalised Least Squares (GLS) regression technique with a spatial analysis of model residuals. Predictions from the GLS model are ‘corrected’ using weighted averages of model residuals following an analysis of spatial correlation. The method was applied to channel substrate data from the River Habitat Survey in Great Britain. A Channel Substrate Index (CSI) was derived using Correspondence Analysis and predicted using regression kriging. The model explained 74% of the main sample variability and 64% in a test sample. The model was applied to the English and Welsh river network and a map of CSI was produced. The proposed approach demonstrates how existing national monitoring data and geostatistical techniques can be used to produce continuous maps of habitat indices at the national scale.

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... Characterisation of river types is a frequent occurrence within river studies, with over 100 river typologies developed over the past 125 years [14]. Both scientific and management-driven approaches for typology development have the same fundamental aim: to reduce the complexity of the river system to a practically useful set of types [3]. ...
... Previous attempts at top-down typologies have been criticized for using a small number of variables relating to only few aspects of catchment functioning; for example, the current typology employed by the WFD separates catchments based only on upstream area, elevation and geology [20] (Table 1). This causes overlap between river types because of external elements not included in the typology such as vegetation, climate and natural variability [14]. In particular, geomorphic characteristics of catchment morphometry that influence hydrological and sedimentological inputs to reaches [21] are often only accounted for via elevation (Table 1). ...
... Hard rock %  Rock permeability influences the flashiness of the hydrograph [51,52].  Rock type determines the sediment calibres available in the catchment [14]. ...
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Multiple catchment controls contribute to the geomorphic functioning of river systems at the reach-level, yet only a limited number are usually considered by river scientists and managers. This study uses multiple morphometric, geological, climatic and anthropogenic catchment characteristics to produce a single national typology of catchment controls in England and Wales. Self-organising maps, a machine learning technique, are used to reduce the complexity of the GIS-derived characteristics to classify 4485 Water Framework Directive waterbodies into seven types. The waterbody typology is mapped across England and Wales, primarily reflecting an upland to lowland gradient in catchment controls and secondarily reflecting the heterogeneity of the catchment landscape. The seven waterbody types are evaluated using reach-level physical habitat indices (including measures of sediment size, flow, channel modification and diversity) extracted from River Habitat Survey data. Significant differences are found between each of the waterbody types for most habitat indices suggesting that the GIS-derived typology has functional application for reach-level habitats. This waterbody typology derived from catchment controls is a valuable tool for understanding catchment influences on physical habitats. It should prove useful for rapid assessment of catchment controls for river management, especially where regulatory compliance is based on reach-level monitoring.
... Many of the lake and wetland sediments known to support AOM are probably impermeable silts and clays [20,21,23], where diffusion delivers the solutes that sustain microbial metabolism [36]. In contrast, the gravel and sandy sediments which dominate UK riverbeds [37] are more permeable [38,39], allowing greater advective flux of nutrients (inorganic nitrogen and phosphorus etc.,) and methane through the riverbed. Even though the bulk porewater of such riverbeds has appreciable oxygen, anaerobic metabolism (e.g., anammox and denitrification) can occur in anoxic microsites [39,40]. ...
... However, given that nitrate is typically more abundant than nitrite [65], it is more reasonable to use the AOM potentials measured with 13 CH 4 + NO 3 − to estimate the role of NO x − -dependent AOM in attenuating methane emissions from sandy riverbeds. Accordingly, for the sandy riverbeds that are common in the UK (~26% of 9459 sites [37]) and probably beyond, we estimate that microbial methane oxidation is about 35% anaerobic and 65% aerobic. In more permeable and widespread gravel beds (48% of UK sites; [37]), however, methane oxidation is carried out almost exclusively by aerobic methanotrophs [32,64,66]. ...
... Accordingly, for the sandy riverbeds that are common in the UK (~26% of 9459 sites [37]) and probably beyond, we estimate that microbial methane oxidation is about 35% anaerobic and 65% aerobic. In more permeable and widespread gravel beds (48% of UK sites; [37]), however, methane oxidation is carried out almost exclusively by aerobic methanotrophs [32,64,66]. In addition to NO 2 − and NO 3 − , SO 4 2− , and Fe 3+ also stimulated AOM in the most reduced sediment from the Hammer Stream (Table 1), suggesting that high methane concentrations support a greater diversity of AOM pathways; although the potential rates for SO 4 2− and Fe 3+dependent AOM were lower than NO x − -dependent AOM. ...
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... To reflect the magnitude of physical modifications to river channels we obtained the Channel Resectioning Index (CRI) dataset [13]. The CRI dataset contains a series of points quantifying the extent of channel resectioning at 500 m intervals along the 1:50,000 Digital River Network of Great Britain [14] modelled from the UK River Habitat Survey database [15]. ...
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Article
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Scientists and practitioners working on river restoration have made progress on understanding the recovery potential of rivers from geomorphological and engineering perspectives. We now need to build on this work to gain a better understanding of the biological processes involved in river restoration. Environmental policy agendas are focusing on nature recovery, reigniting debates about the use of “natural” reference conditions as benchmarks for ecosystem restoration. We argue that the search for natural or semi-natural analogues to guide restoration planning is inappropriate due to the absence of contemporary reference conditions. With a catchment-scale case study on the invertebrate communities of the Warwickshire Avon, a fifth-order river system in England, we demonstrate an alternative to the reference condition approach. Under our model, recovery potential is quantified based on the gap between observed biodiversity at a site and the biodiversity predicted to occur in that location under alternative management scenarios. We predict that commonly applied restoration measures such as reduced nutrient inputs and the removal of channel resectioning could be detrimental to invertebrate diversity, if applied indiscriminately and without other complementary measures. Instead, our results suggest considerable potential for increases in biodiversity when restoration measures are combined in a way that maximises biodiversity within each water body.
... This paper thus focuses on examples and case studies, illustrating how the original PSI index has been used in practice at both national and local scales. An assessment of the utility of the technique at the national scale was accomplished by using monitoring data from England and Wales, for the period 2010-2012, to examine how well PSI scores correlated with a channel substrate index (CSI) designed to describe a gradient between fine-sedimentand coarse-sediment-dominated sites (Naura et al., 2016a). ...
... For each site, CSI values were derived using predictive models for both the current condition and seminatural conditions. For full details of the approach, reference should be made to Naura et al. (2016a), but, in summary, the CSI is derived from River Habitat Survey spotcheck data (visual assessment of the dominant river substrate; see Raven, Fox, Everard, Holmes, & Dawson, 1997, for full details of the survey method) and describes a gradient between fine-sediment-and coarse-sediment-dominated sites (CSI at silt-dominated sites = −2.3, gravel-pebble = −0.6, ...
Article
Sedimentation of river beds is a key pressure impacting riverine ecological communities. Research has identified the need for new approaches to help demonstrate and quantify the impacts of excessive fine-sediment deposition on benthic macroinvertebrate populations. To help meet this requirement, the Proportion of Sediment-sensitive Invertebrates (PSI) methodology was developed and has been in operational use in the United Kingdom for several years. This paper presents a number of case studies, at both national and local scales, showing how the method can be used to identify point and nonpoint fine-sediment pollution, as well as demonstrating the analysis of a national dataset to describe the relationship between PSI and a channel substrate index. A novel approach to displaying PSI data alongside local ecological and hydrological information is also presented and interpreted, to illustrate how improved understanding of biotic and abiotic relationships and interactions can be readily accomplished. Excessive fine-sediment accumulation on river beds results in impaired ecosystem health globally. The case studies and examples presented here will provide confidence that the PSI method can form the basis for evidence gathering and analysis, both within and beyond the United Kingdom. The paper concludes with an overview of the use of PSI in catchment research and management, a consideration of the relationship of the metric with other macroinvertebrate indices, and a summary of refinements recently applied to the index.
... In Greece, it has been used for research purposes in large projects, such as the STAR project [22], and in local or regional studies [23,24]. The method is WFD-compliant and is based on a detailed assessment of different hydromorphological components and features with the implementation of two indices: (a) the Habitat Modification Score (HMS), which accounts for the overall hydromorphological changes in the reach, and (b) the Habitat Quality Assessment (HQA), which assesses the physical characteristics and processes [25]. The HQA requires the establishment of a relatively large database including enough records of reference sites with no or minimal anthropogenic disturbance in order to adjust the index for suitability of assessment of the Greek streams and rivers. ...
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The ecological assessment of all surface water bodies in Europe according to the Water Framework Directive involves the monitoring of biological, physicochemical and hydromorphological quality elements. For the hydromorphological assessment in particular, there are numerous methods that have been developed and adopted by EU member countries. With this study, we compared three different methods (River Habitat Survey, Morphological Quality Index and River Hydromorphology Assessment Technique) applied in 122 river reaches that are part of the National Monitoring Network of Greece. The main objectives were (a) to identify whether different assessment systems provide similar classifications of hydromorphological status and (b) to distinguish strengths and weaknesses associated with the implementation of each method. Our results show that the River Hydromorphology Assessment Technique (RHAT) and the Morphological Quality Index (MQI) resulted in the same classification for 58% of the studied reaches, while 34% of the remaining cases differed by only one quality class. Correlations between the two indices per river type (ICT) showed that the two indices were strongly correlated for water courses located at low altitudes. Concerning the HMS index of the River Habitat Survey (RHS), which is an index that reflects the overall hydromorphological pressure, it showed larger differences with the other two indices, mainly because it classified more sites as “Poor” and “Bad” quality classes. Based on our results, we recommend that the two indices, RHAT and MQI, can be implemented complementary to the RHS for providing a rather easy and quick assessment of the overall hydromorphological status, at least until a national hydromorphological database is compiled that will allow for the proper adaptation of the Habitat Quality Assessment (HQA) index.
... In further analysis, the first principal components, which together explain 99% of the variance, were used.Spatial prediction of IEW risk was carried out by RK(Hengl, Heuvelink, & Rossiter, 2007). This geostatistical method has been used successfully in previous environmental modelling studies, like biomass mapping(Bouwmeester, Heuvelink, & Stoorvogel, 2016;Fayad et al., 2016;Hernández-Stefanoni, Alberto Gallardo-Cruz, Meave, & Dupuy, 2011), forest research(Illés, Kovács, & Heil, 2011), habitat mapping(Hengl, Sierdsema, Radović, & Dilo, 2009;Naura et al., 2016), snow and ice load estimation(Nygaard, Seierstad, & Veal, 2014;Perčec Tadić, Zaninović, & Sokol Jurković, 2015), and natural hazard mapping(Cathcart, Aherne, Jeffries, & Scott, 2016;Pásztor, Szabó, Szatmári, Laborczi, & Horváth, 2016). RK is a spatial predicting method combining the advantages of MLR and interpolation methods.By RK, at first, the target variable is modelled by MLR of the environmental covariables, then the spatial extension of the residuals (the difference between the original and the modelled values) is carried out by ordinary kriging. ...
Article
Inland excess water (IEW) is a form of surplus surface water, often regarded as a specific flood type. However, it occurs most frequently in local depressions of large flat areas, irrespective of river floods and the surface water networks. IEW is considered to be a typical Carpathian Basin problem, as it can cause major land degradation problems in the agricultural areas of Hungary mainly located on the Great Hungarian Plain (GHP). An innovative method for mapping the probability of IEW inundation is proposed in this study. This method is based on the geostatistical modelling of the relationship between the natural and human driving factors and the occurrence of IEW inundations. The results show that significant part of the GHP (about 500,000 hectares) is moderately or highly affected by IEW inundations where the combination of multiple influencing factors simultaneously occur. The resulted IEW inundation probability map can be used to meet future challenges in agricultural management and the adaptations to climate change effects.
... As reported by Hering et al. (2010), there is still a lack of homogeneity across or even within state boundaries regarding the monitoring in the scope of the WFD. As a consequence, the variety of assessment methods hampers data comparability-a key prerequisite to efficiently plan conservation or management measures (Pardo et al. 2012;Naura et al. 2016). Broadscale monitoring and restoration programmes across political boundaries are significantly weakened if ground data do not provide a homogenous basis necessary to reliably analyse the hydromorphological status of water bodies. ...
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Hydromorphological assessment methods as the on-site assessment of the German Working Group on water issues (LAWA-OS method) provide valuable information for a wide range of water management issues like water body assessment, deficit analysis and planning or monitoring of restoration projects. Considering these demands, the question about the assessment variability of such methods arises. Depending on varying aims, scales and approaches different methods may show contradictory assessment results. The objectives of this work are to quantify assessment deviations between different versions of the LAWA-OS method and to identify the causes of these deviations. The hypothesis is that procedural differences between versions act as deviation factors and lead to scoring discrepancies. A pairwise comparison between assessment results of two representative versions show that the LAWA-OS method is very robust against deviation factors on the overall score level. With increasing differentiation of hydromorphological characteristics on the main parameter and single parameter level, the assessment robustness decreases considerably. Particularly, differing numbers of parameters, differing reference scores and differing score aggregation procedures act as factors for substantial assessment deviations between versions. The work in hand provides scientifically based outputs in relation to the reliability, comparability and applicability of the LAWA-OS assessment results for river ecology issues. In this regard, the work in hand contributes to the quality control of the LAWA-OS method and provides valuable insights for practitioners and policy makers.
... The variogram describes the measure of dissimilarity (semivariance) against the distance and di-rection of separation (lag vector; Webster & Oliver 2007). Spatially uncorrelated data display no observable change in semivariance with increasing lag distance (flat variogram, or more irregular but not increasing), while spatially correlated data are represented by a monotonically increasing semivariance as the lag distance between sites increases (Naura et al. 2016). In cases where spatial autocorrelation occurred, we developed a new full GLS model in which we added a spatial autocorrelation structure (correlation = corSpatial) with latitude and longitude to the model framework. ...
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The implementation of agri-environment schemes (AES) in Poland began in 2004, yet the effects of their implementation were not systematically monitored until 2010. Using monitoring data collected in 2011 from two regions of Poland, the foothills and the lowlands, we examined the impact of environmental variables and the AES on 1) the number of species , 2) the number of territories of all breeding species, 3) the number of territories of target species for bird-oriented AES, and 4) the numbers of territories of the eight most frequent farmland species. More species and a larger number of territories were recorded in the lowland study plots than in the foothill ones. The proportion of land covered by AES on the study plots had no impact on the number of species or the numbers of territories of all species in either region. Furthermore, the relationship between the number of territories of target species and the proportion of land covered by AES in the lowland region was negative. Environmental variables significantly affected the numbers of territories of two numerous farmland species in the foothill region and three species in the lowlands. The implication of these results is that the AES dedicated to bird conservation need further assessment. To be more effective, the AES have to allow for regional variation; they definitely require further, detailed study.
... (WQI) and water pollution index (WPI) are among the leading parameters to assess the quality of water (Lermontov et al., 2009;Wang et al., 2015;Naura et al., 2016). Number of water quantity and water quality issues are related to the infrastructure of water flowing bodies which leads to different types of chemicals and wastes addition into drinking water and turn the green aqua environment into a hazardous body. ...
Chapter
Water pollution presents a significant menace to the environment and life itself. One-third of the living population lacks access to clean drinking water. A large portion of the world's population suffers from waterborne diseases because of drinking contaminated water. Water pollution is caused by both natural and anthropogenic sources. The Industrial Revolution has produced amounts of industrial wastes in marine and fresh water, creating serious health complications for the biota. Increased human population has also brought more waste products, including toxic chemicals, cosmetic products, organic debris, and biological pollutants in fresh water. Some of these chemicals are highly toxic in nature; therefore it is necessary to detect their presence. Conventional methods have difficulties in sensing and quantification of many water pollutants. The equipment used for detection is expensive and has limited portability with high maintenance cost. Modern strategies for the detection of water pollutants have been investigated to make the equipment smaller and more robust, cost-effective, and highly selective. Among these strategies, nanostructured devices are effective because of their high efficiency, accuracy, and low energy demand. Water monitoring is one of the major applications of nanosensors, which detect pollutants created through different natural and anthropogenic sources. Water quality can be improved by rapid monitoring of major water contaminants. These sensing devices detect water pollutants in the real-world environment. This chapter focuses on detection of heavy metals, pesticides, chemical oxygen demand, biological oxygen demand, industrial waste, biological pollutants, and emerging pollutants through modern nanosensors.
... Hydromorphological features and modifications of the sites of the sampling network are recorded once for the duration of the monitoring period according to the River Habitat Survey (RHS) method. The RHS is a commonly used system for assessing the habitat quality and the hydromorphological modification of rivers [5,16]. The method involves filling a detailed field protocol during a survey of a 500m length of river channel. ...
Article
Full-text available
The Water Framework Directive (WFD) requires from member states to monitor hydromorphological features of rivers in order to assess their ecological quality. Thus, numerous hydromorphological assessment methods have been developed with most of them focusing on the dynamics of hydrology, geomorphology and riparian zone extent. Within the scope of this study, we assessed the hydromorphological features of 106 river reaches distributed among thirteen WFD River Basin Districts (RBDs) to identify the main drivers of hydromorphological perturbation at a national scale. The studied reaches reflect a wide range of natural variability as they include various types of watercourses extending from lowlands to mid-altitude and mountainous systems. We employed the River Habitat Survey (RHS), and we recorded hydromorphological features and modifications in both banks and the channel bed along 500 m for each reach. Then, the Habitat Modification Score (HMS) and the individual sub-scores that indicate the extent of specific modifications (e.g., bridges, fords, weirs, bank reprofiling, bank reinforcement, etc.) were calculated in order to a) assess the severity of the total artificial modification and b) to highlight the most common and severe causes of overall alteration. The results showed that alterations such as reprofiling and reinforcement of banks contributed the most to the total HMS followed by the presence of fords and bridges. Particularly, the bank alterations indicate a serious deterioration of the longitudinal profile of the reaches, while the occurrence of many fords and bridges is the main cause for perturbations that affect locally the stream cross-sectional profile. Overall, these results compile a first nationwide assessment of the hydromorphological status of Greek rivers in line with the WFD and set the basis for further research that will focus on the diversity of stream habitat features as a measure for the overall ecological quality.
... The small-scale contrast experiment methods are at a finer scale than other methods, although it is not applicable to large-scale areas because of the lack of data. The numerical simulation based on the interaction between water ecological and physical mechanisms is mainly represented by hydrodynamic models and habitat models which can identify the dynamic relationship among flow, water level, and critical habitat sections in rivers (Ramón et al., 2015;Naura et al., 2016;Schneider et al., 2017;Chen-Lin et al., 2018;Meert et al., 2018;Stamou et al., 2018). As a typical hydrodynamic model, the MIKE serial models have been frequently used, whereas the Physical Habitat Simulation Model (PHASIM) models are often used for the habitat area simulation (Panda et al., 2010;Li et al., 2013;Yi et al., 2017;Boavida et al., 2018). ...
Article
Analyzing the instream environmental flow demand by coupling the hydrological cycle and the hydrodynamic process with aquatic ecological processes at watershed scale remains one of the most important yet most difficult issues. One or two of the above processes have been the focus in the evaluation of intra-annual ecological water demand in recent studies. In this study, a hydrology-hydrodynamic-habitat model was developed and applied to the Huangshui River basin. A new classification method for instream ecological water demand (IEWD), which considered sensitive species was proposed. The suitable level of IEWD and crucial values with different flow frequencies were analysed, including runoff, water level, water surface width and weighted usable areas (WUA). The results of the study indicated that monthly IEWD had an increasing trend during the flood season and a decreasing trend during the non-flood season in three sections at different suitable levels. With the increase of suitable levels, the range of IEWD in three sections also increased. The IEWD and crucial values were the lowest in March with the smallest range and were the highest from July to October because the amount of precipitation during that period accounted for nearly 84.3% of that of the entire year. Furthermore, the lower the flow frequency in three sections, the higher the suitable levels of IEWD, as well as water level and water surface width every month. When the flow frequency of 90% decreased to 75%, the value of IEWD increased by at least 55% during the wet season and doubled during the dry season. The WUA with the lowest or highest flow frequencies were relatively poor, especially reproduction period. The IEWD and crucial values at different suitable levels agreed with the actual situations. Thus, this study provided a new method for implementing river ecosystem restoration and aquatic ecosystem management.
... Therefore, a multitude of RHS variables may be used to characterize different groups of river physical features. In this context, predicting and mapping RHS characteristics with ecological relevance (Naura et al., 2016;Vaughan, Merrix-Jones, & Constantine, 2013) may constitute a useful tool for river research and management. ...
Article
The physical characteristics of river habitats constitute the setting in which fluvial biota dwell and thrive. Determining the spatial and temporal patterns of physical habitat characteristics and the main factors that control them is extremely important to increase the efficiency of river management, conservation, and restoration. This study determined spatial patterns of physical habitat characteristics for Atlantic and Mediterranean rivers in northern Spain and developed a river classification based on hydromorphological characteristics. Data gathered from almost 600 sites following a modified version of the River Habitat Survey methodology were used. In addition to the usual River Habitat Survey variables, the sequence of hydromorphologic units (i.e., areas exhibiting similar hydraulic characteristics, in terms of water velocity and depth), water depths, and widths were recorded. Unmodified reaches were selected computing the Habitat Modification Score. Multiple Linear Regression models were employed to test relationships between Principal Component Analyses that summarized physical river habitat characteristics with ecological relevance and environmental variables (i.e., climate, topography, land cover, and geology) at different spatial scales and used to predict physical habitat attributes for all river reaches. The density of hydromorphologic units, flow turbulence, substrate size, and channel dimensions were able to discriminate river classes within the river network, with topography being the main environmental driver of habitat characteristics (although climate, geology, and land cover were also relevant). This classification scheme could constitute a useful tool to restore physical habitat conditions in modified river reaches.
... In particular, it is challenging to obtain information on (i) channel shifting and braided planform changes; (ii) interactions between groundwater and surface runoff (potentially very important for understanding habitat patterns in the braided river system) (Belletti et al., 2013;Malard et al., 2006), and (iii) vegetation recruitment, growth and scouring, which is largely unknown in such high-altitude environment. These difficulties are because the existing methods for examining the characteristics of river vegetation or the abovementioned interactions largely rely on second-hand survey data and higher resolution optical images, such as airborne LiDAR, aerial, or multispectral images and Unmanned Aerial Vehicle (UAV) photos (Hugue et al., 2016;Lallias-Tacon et al., 2017;Naura et al., 2016;Sanhueza et al., 2019;Solari et al., 2015). These data are not available for braided rivers in the ULR and other remote regions. ...
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Functional characteristics of braided rivers with very high elevations (>3400 m) located in the Qinghai-Tibet Plateau, China provide unique insight into fully understanding global braided river functioning, but have not yet been explored because of their remote locations and harsh physiographic conditions. In this study, we unveiled these characteristics at the reach spatial scale over three decades in one of these braided rivers, the Upper Lancang River (ULR). Using Google Earth Engine resources and a specific selection of Landsat images obtained between 1989 and 2018 during the dry season (November to early May when water levels were low and comparable over years), we analyzed water area, extracted flowing and non-flowing channels, active channel widths (unvegetated bars and water channels), and calculated lateral shifting rates of the main channel for 13 sub-periods. We also developed an empirical method for estimating vegetated areas in the selected years. We found that (1) this braided system is partly controlled by peak flows and flood durations and the braiding activity evolved through time according to braided planform characteristics, (2) braiding intensity is high during low discharges, suggesting that the ULR is a very well-connected braided system with groundwater, but we observed higher braiding activity in spring than in fall, suggesting other factors than groundwater recharge also control non-flowing channel occurrence, and (3) the ULR supports a vegetation mosaic that is dynamic at a multi-year scale with period of declines that can be caused by scouring and rapid growth in an optimal recruitment window. These findings lead to our interpretation of vegetation behavior and surficial water – groundwater interactions, which needs future field validation.
... Whilst the physical habitat indicators developed in this project are considered to be fit for purpose, it is known that similar indicators have been generated by others with a view to informing future UK WFD assessments and local investigations (Naura et al. 2016). There may be scope for collaborative working to agree a common set of indicators that addresses both needs, to facilitate information sharing and reduce the costs of data processing. ...
Technical Report
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This report summarises work undertaken by Natural England and the Centre for Ecology and Hydrology, in collaboration with the Environment Agency, to develop proposals for a framework to monitor and assess the status of priority freshwater habitats in England. It forms part of a series of actions arising from Biodiversity 2020 to refine the strategy for conserving priority freshwater habitats. The work takes as its foundation the concept of natural ecosystem function (described in detail in the 'freshwater and wetland habitat narrative', Mainstone et al. 2016), which underpins the health of all freshwater habitats whether they are specially protected sites, priority freshwater habitats, waterbodies designated under the EU Water Framework Directive, or any combination of these. The report seeks to provide a framework for assessing key aspects of natural ecosystem function, harmonising with recent work to map priority freshwater habitats and bring greater clarity to the conservation strategy for the freshwater SSSI series. Freshwater habitats have benefited from an extensive monitoring and assessment programme under the Water Framework Directive. Further relevant data are provided by Countryside Survey and other programmes. The project has developed a framework for making best use of available data, only proposing additional elements of data collection and processing where needed to provide a coherent picture of the naturalness of ecosystem function across the freshwater habitat resource. The work covers rivers and streams, lakes and ponds and proposes a series of attributes for each. These attributes seek to characterise the main elements of natural ecosystem function, including hydrological, physical, chemical and biological integrity. A holistic approach is proposed involving the whole of the habitat resource, not just those sites on the priority habitat maps produced for England. This is because sites that will not meet the criteria for inclusion on freshwater priority habitat maps in the future can still contribute to the achievement of priority habitat objectives through various degrees of restoration of natural habitat function. The proposed sampling design is mixed, reflecting existing monitoring programmes on which the framework is based. Elements relating to small waterbodies necessarily use representative sampling, and this has important consequences for how the data can be used in biodiversity reporting. Data are categorised according to a five-class classification, allowing improvements in habitat condition to be followed through time, building on the ecological status classification used for the Water Framework Directive. A more detailed technical summary is available at: http://publications.naturalengland.org.uk/publication/4635950369472512?category=2433118
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Attempts to obtain information from geospatial data in freshwater ecology is a highly challenging task requiring the development of new concepts and adequate tools. Conventionally, river networks are represented as collections of vectors, but they can also be thought of as a succession of raster cells corresponding to the digital elevation model of the landscape they traverse. Based on the principle that each cell in the river raster collects environmental influences from its upstream drainage basin, we defined a remote measure of the potential of pollution named RWQ (Remote Water Quality). We used the CORINE Land Cover categories found in the catchment area of each cell in the river network grouped by ecological relevance and weighted by their respective areas in the catchment. To refine the index to account for the proximity of potential pollution sources, we tested successive buffers of 1 km up to the full catchment of each investigated point, concluding that the RWQ calculated for the full catchment is the most suitable index. For implementation, we developed RIVERenhancer, a free Python-based ArcGIS tool making possible the enhancement of raster river networks with data extracted from various files. The reliability of RWQ was tested with the aid of in situ measurements of chemical and biological water quality obtained from several sources in Danube basin (Romania and Hungary). The strong correlation with field data shows that this index can be considered a surrogate to depict the quality of freshwater habitats and to analyse network heterogeneity. The strength of this concept comes from taking advantage of the dendritic nature of river networks, opening new directions of operations for large scale approaches concerning important issues in global ecology, biogeography and conservation.
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The spatial arrangement of the river network is a fundamental characteristic of the catchment, acting as a conduit between catchment-level effects and in-channel morphology and ecology. Yet river network structure is often simplified to reflect an up-to-downstream gradient of in-channel features, commonly represented by stream order. The aim of this study is to quantify network topological structure using new metrics – distance network density and elevation network density – that better account for the multi-dimensional nature of the catchment and which are functionally applicable across geomorphological, hydrological and ecological attributes of the catchment. The functional utility of the metrics in explaining patterns of physical habitat diversity is assessed in comparison to stream order. The metrics are calculated for four low-energy, anthropogenically modified catchments in the UK and compared to a physical habitat diversity score derived from England's River Habitat Survey. The results indicate that the new metrics offer a richer, and functionally more-relevant description of network topology than stream order, highlighting differences in the density and spatial arrangement of each catchment's internal network structure. Correlations between the new metrics and physical habitat diversity score show that distance network density is positively related to maximum habitat diversity in three of the four catchments. There is also evidence that increased distance network density may reduce minimum habitat diversity in catchments with greater anthropogenic modification. When all catchments are combined, distance network density is positively correlated with maximum, mean and minimum habitat diversity. There are no significant correlations between elevation network density and habitat diversity. In all but the largest streams, there is no significant relation between habitat diversity and stream order highlighting the limitations of stream order in accounting for network topology. Overall, the results suggest that distance network density is a more powerful metric which conceptually provides an improved method of accounting for the impacts of network topology on the fluvial system exhibiting strong relationships with habitat diversity, particularly maximum habitat diversity.
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The spatial arrangement of the river network is a fundamental characteristic of the catchment, acting as a conduit between catchment-level effects and reach morphology and ecology. Yet river network structure is often simplified to reflect an upstream-to-downstream gradient of river characteristics, commonly represented by stream order. The aim of this study is to quantify network topological structure using two network density metrics – one that represents network density over distance and the other over elevation – that can easily be extracted from digital elevation models and so may be applied to any catchment across the globe. These metrics should better account for the multi-dimensional nature of the catchment than stream order and be functionally applicable across geomorphological, hydrological and ecological attributes of the catchment. The functional utility of the metrics is assessed by appropriating monitoring data collected for regulatory compliance to explore patterns of river characteristics in relation to network topology. This method is applied to four comparatively low-energy, anthropogenically modified catchments in the UK using river characteristics derived from England's River Habitat Survey database. The patterns in river characteristics explained by network density metrics are compared to stream order as a standard measure of topology. The results indicate that the network density metrics offer a richer and functionally more relevant description of network topology than stream order, highlighting differences in the density and spatial arrangement of each catchment's internal network structure. Correlations between the network density metrics and river characteristics show that habitat quality score consistently increases with network density in all catchments as hypothesized. For other measures of river character – modification score, flow-type speed and sediment size – there are varying responses in different catchments to the two network density metrics. There are few significant correlations between stream order and the river characteristics, highlighting the limitations of stream order in accounting for network topology. Overall, the results suggest that network density metrics are more powerful measures which conceptually and functionally provide an improved method of accounting for the impacts of network topology on the fluvial system.
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Summary Five different methods for hydromorphological characterization and classification of rivers were applied to selected reaches of the rivers Surna (35 km) and Gudbrandsdalslågen (15 km) to test their suitability for the development of a Norwegian method for hydromorphological classification complying with the requirements of the European Water Framework Directive (WFD). Three of the methods (River Habitat Survey, Morphological Quality Index and Swedish River Classification) have been used or developed in connection with the WFD. The Environmental Design Method and the system Nature in Norway 2.0 are Norwegian methods designed for other purposes. All methods are based on information from Geographical Information Systems (GIS), albeit to varying degrees. The river classification for Lågen reflected large variations in slope and was similar across the the different methods. However it was not in agreement with the WFD-related water body delineation. The classification for Surna revealed larger distinctions across methods, as a result of methodological differences in the handling of the effects of regulation and human disturbances. The results cannot be generalized as such and further testing of the methods is needed in additional rivers of different characters. The use of high-resolution data from remote sending is recommended, as is the development of automatized routines for hydromorphological classification. Sammendrag Fem ulike metoder for hydromorfologisk karakterisering og klassifisering av elver ble testet ut for utvalgte vannforekomster i Surna (35 km) og Gudbrandsdalslågen (15 km), for å teste hvorvidt de er egnet for utvikling av en norsk metode for hydromorfologisk klassifisering i henhold til vannforskriften. Tre metoder (River Habitat Survey, Morphological Quality Index og Swedish River Classification) har blitt brukt eller utviklet med hensyn til EU vanndirektivet. Miljødesignmetoden og systemet Natur i Norge 2.0 er norske metoder som ble utviklet for andre formål. Alle metoder baserer seg i ulik grad på informasjon fra Geografiske Informasjonssystemer (GIS).Inndelingen i avsnitt for Lågen gjenspeilet store variasjoner i helning og var nesten sammenfallende for de ulike metodene, men ikke med inndelingen som er gjort etter vannforskriften. Avsnittsinndelingen for Surna viste større forskjeller, som gjenspeiler ulik håndtering av reguleringseffekter og menneskelige inngrep i metodene. Resultatene kan ikke generaliseres og metodene må testes i flere vassdrag av ulik karakter. Det anbefales å ta i bruk høytoppløste data fra fjernmåling og utvikle automatiserte rutiner for hydromorfologisk klassifisering.
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Gregory’s pioneering work on progressive river channel change, driven in England by both natural and anthropogenic forces, helped to guide major concepts and roles for fluvial geomorphology. It opened the door to a steep rise of applied fluvial geomorphology and a bigger role in public policy and river basin management. The channel change paradigm spans the millennia; by the late 20th Century, the extent of Anthropocene harm to rivers justified both a radical label as ‘damage’ and a professional focus to prescribe remedies. Imitating engineering, then dominant in river management, Gregory favoured the term ‘design’. The damage principally impacted river habitat and increasing collaboration with freshwater ecologists in the restitution of damage became part of the international move to ‘river science’. European legislation strengthened the legal status of physical habitat in overall river quality. In the 21st Century fluvial geomorphology has both strengthened and diversified further within ‘river science’, but also gaining social, behavioural, even political, insights through ‘citizen science’ and the ‘co-design’ of river corridor projects with communities. The professional challenges of the climate and biodiversity emergencies return us to Gregory’s question, ‘how applied should we become?’ The increasingly public profiles of, for example, flood risk policy require river scientists to participate in recommending and co-designing options such as rehabilitation, restoration and rewilding. The separate and joint contributions of these options are discussed through the geomorphological prism. Progressive and episodic channel changes will increase as the drivers and remedies interact; we must play a role in scenario setting and adaptive management, promoting workable collaboration between natural and social sciences, especially in the contested field of design.
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Scenarios of changes in biodiversity for the year 2100 can now be developed based on scenarios of changes in atmospheric carbon dioxide, climate, vegetation, and land use and the known sensitivity of biodiversity to these changes. This study identified a ranking of the importance of drivers of change, a ranking of the biomes with respect to expected changes, and the major sources of uncertainties. For terrestrial ecosystems, land-use change probably will have the largest effect, followed by climate change, nitrogen deposition, biotic exchange, and elevated carbon dioxide concentration. For freshwater ecosystems, biotic exchange is much more important. Mediterranean climate and grassland ecosystems likely will experience the greatest proportional change in biodiversity because of the substantial influence of all drivers of biodiversity change. Northern temperate ecosystems are estimated to experience the least biodiversity change because major land-use change has already occurred. Plausible changes in biodiversity in other biomes depend on interactions among the causes of biodiversity change. These interactions represent one of the largest uncertainties in projections of future biodiversity change.
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Human activities have severely affected the condition of freshwater ecosystems worldwide. Physical alteration, habitat loss, water withdrawal, pollution, overexploitation and the introduction of non-native species all contribute to the decline in freshwater species. Today, freshwater species are, in general, at higher risk of extinction than those in forests, grasslands and coastal ecosystems. For North America alone, the projected extinction rate for freshwater fauna is five times greater than that for terrestrial fauna—a rate comparable to the species loss in tropical rainforest. Because many of these extinctions go unseen, the level of assessment and knowledge of the status and trends of freshwater species are still very poor, with species going extinct before they are even taxonomically classified. Increasing human population growth and achieving the sustainable development targets set forth in 2002 will place even higher demands on the already stressed freshwater ecosystems, unless an integrated approach to managing water for people and ecosystems is implemented by a broad constituency. To inform and implement policies that support an integrated approach to water management, as well as to measure progress in halting the rapid decline in freshwater species, basin-level indicators describing the condition and threats to freshwater ecosystems and species are required. This paper discusses the extent and quality of data available on the number and size of populations of freshwater species, as well as the change in the extent and condition of natural freshwater habitats. The paper presents indicators that can be applied at multiple scales, highlighting the usefulness of using remote sensing and geographical information systems technologies to fill some of the existing information gaps. Finally, the paper includes an analysis of major data gaps and information needs with respect to freshwater species to measure progress towards the 2010 biodiversity targets.
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How do we ensure that scientific tools, techniques and outputs (e.g. models, software, analytical techniques) are used in the ‘applied world’ of industry and government? Many expensive software, models and research outputs are not used, or fail at the implementation stage. In this book, we investigate the factors affecting the uptake of a group of software called Decision Support Systems (DSS) in organisations. We particularly concentrate on the study of DSS interactions with organisational culture, and the ‘frictions’ that assumptions taken in their design may generate with existing work practice and organisational beliefs, potentially leading to their rejection by users. We further propose a methodology for developing DSS that accounts for organisational and cultural factors, with the aim of increasing user acceptance and uptake. We demonstrate the application of the proposed methodology in a case study with a major environmental organisation in the United Kingdom.
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Predictions of river channel form under current conditions or in response to environmental or management changes and the rapid comparison of different channel reaches are important tasks in river management. River classification is a common and valuable framework to address these aims but may suffer from the necessity to force a continuum of channel morphology into discrete groups. More generally, the scope to test the ability of predictive tools has been limited because of a shortage of field data. In this study, we used principal component analysis (PCA) to identify the main sources of variation among river reaches in England and Wales based on a set of 20 variables expected to correlate with channel morphology. The PCA scores were then used to predict the distributions of a wide range of hydromorphic features based on > 4000 reaches surveyed in the River Habitat Survey baseline. For comparison, the predictive ability of three pairs of variables (channel slope–discharge, slope–catchment area, and specific power–catchment area) was also tested. The PCA identified specific stream power, channel size and groundwater input as the main sources of variation among reaches. Regression models using PCA scores or paired variables were effective predictors of a range of channel characteristics, including predominant substrate, flow biotopes, and channel vegetation. Channel cross sections and anthropogenic modifications were less predictable. All of the approaches permitted simple plots of river reaches and quantitative comparisons of the (dis)similarity among individual reaches, whilst the paired variables also minimised the data requirements. Our work reiterates the value of simple, paired variables as a basis for rapidly comparing river reaches and, for the first time, quantifies the predictive ability of these approaches across a wide range of channel characteristics at a national scale. Principal component analysis provides a valuable exploratory tool for identifying the main sources of variation in complex, multivariate data from which a simplified version (e.g., specific power and area) could be adopted.
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1. The extensive data collected from more than 5000 separate sites in England, Wales, Scotland and Northern Ireland now provide representative samples of the current state of river habitats in the UK. 2. While analysis and interpretation of these data will necessarily continue for some time, some preliminary conclusions and results have already emerged from the examination and interpretation of the complex and dynamic relationships between the many variables and attributes recorded in the course of the national survey. 3. In particular, it has been possible to provide an ordination of the survey sites based on four map-derived variables that facilitates prediction of at least some of the major habitat features. 4. This ordination and the resulting prediction of habitat features are described in this paper, together with a brief discussion of the implications of the analysis for river habitat management.
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Discusses different types of river classification including objective classification by multivariate analyses. Describes incremental analysis of the stream environment, and develops a geomorphological classification of New Zealand rivers. From questionnaire survey it was discovered that channel characteristics were unimportant in the assessment of valley scenery. -K.Clayton
Article
1. This paper sets out the background to river channel classification using geomorphological features; these are highly relevant to the description and understanding of physical habitat.2. The River Habitat Survey (RHS) database contains much geomorphological information which has been statistically analysed for those semi-natural sites surveyed in 1994. Additional geomorphological data have been gathered in an attempt to make the resulting typology ‘dynamic’, i.e. capable of predicting channel stability, an important component of the information needed for sustainable river management.3. The outcome of TWINSPAN and redundancy analyses is disappointing in statistical terms and does not, therefore, constitute an objective taxonomy. However, the river types selected by the analyses are intuitively realistic, and show promise that, with a broader database (both spatially and in terms of independent variables) the development of a predictive, dynamic typology will be possible. © 1998 John Wiley & Sons, Ltd.
Article
Land Cover Map 2000 (LCM2000) is a thematic classification of satellite image data covering the entire United Kingdom. The map updates and substantially upgrades the Land Cover Map of Great Britain (LCMGB), made in 1990–92. This paper outlines the character of the map through a description of its specification, production and outputs. The paper is aimed at users of LCM2000 and derived data who need to understand more of the map and its characteristics. The paper also outlines plans for making data available to researchers and applied users.The most important development in LCM2000 was the spectral segmentation of images to generate vector land parcels. Land cover was then identified by the spectral classification of the image data in these parcels. Classification used specially developed procedures which exploited known spatial, spectral and contextual characteristics of land cover. The resultant GIS incorporates, within its vector structure, detailed attribute data which record parcel-based land cover, plus information on class probabilities, data on within-parcel heterogeneity, information on landscape structure and context, cover information from LCMGB, together with a record of each parcel's processing history.
Article
River surveys are undertaken for a variety of purposes including (i) to establish inventories of particular features and their changes, (ii) to collect data to underpin the classification of river types or to assess resources according to particular criteria, and (iii) to identify sites that have particular qualities or may require particular types of management. In this paper we describe a new reach-scale survey technique, a range of synthetic indices, and a series of classifications specifically developed for application to urban rivers.
Article
A new set of field data facilitates a detailed analysis of variations in bed material grain size within two confluent gravel-bed rivers in northeastern British Columbia, Canada. A preliminary assessment of grain-size variability establishes a basis for examination of the spatial pattern of grain-size change. Standard ANOVA techniques are inappropriate because individual samples have unequal variances and are not normally distributed. Alternative tests for homoscedasticity and comparison of means are therefore utilized. Within-site, between-sample variability is not significant. The grain-size distributions that were obtained at individual sites are therefore representative of the depositional environments that were sampled. In both rivers mean grain size does vary significantly between sites and there is therefore a basis for examining the data for spatial patterns such as downstream fining.Textural variations along the two rivers studied here are complex and show negligible overall fining (in over 100 km). This is the consequence of a large number of tributary inputs and non-alluvial sediment sources which are the legacy of Late Pleistocene glaciation. The identification of lateral sources like these is fundamental for understanding textural changes within rivers. The sedimentary link (a channel reach between significant lateral sediment inputs) provides a means of isolating fluvial maturation processes (abrasion and sorting) from contingent lateral inputs. Strong fining trends are apparent in most links and classification of grain-size measurements according to their location within particular links greatly improves the statistical explanation of textural variation. Identification of sedimentary links provides a means of applying models of fluvial fining processes, so isolation of link networks will aid the development of basin-scale models of textural variation. © 1998 John Wiley & Sons, Ltd.
Article
Conservation biology can benefit greatly from models that relate species' distributions to their en-vironments. The foundation of successful modeling is a high-quality set of field data, and distribution models have specialized data requirements. The role of a distribution model may be primarily predictive or, alter-natively, may emphasize relationships between an organism and its habitat. For the latter application, the environmental variables recorded should have direct, biological relationships with the organism. Interacting species may be valuable predictors and can improve understanding of distribution patterns. Sampling should cover the full range of environmental conditions within the study region, with samples stratified across ma-jor environmental gradients to ensure thorough coverage. Failure to sample correctly can lead to erroneous organism-environment relationships, affecting predictive ability and interpretation. Sampling ideally should examine a series of spatial scales, increasing the understanding of organism-environment relationships, identi-fying the most effective scales for predictive modeling and complementing the spatial hierarchies often used in conservation planning. Consideration of statistical issues could benefit most studies. The ratio of sample sites to environmental variables considered should ideally exceed a ratio of 10:1 to improve the analytical power and reliability of subsequent modeling. Presence and/or absence models may suffer bias if training data detect the study organism at an atypical proportion of sites. We considered different strategies for spatial autocorrelation and recommend it be included wherever possible for the benefits in biological realism, predictive accuracy, and model versatility. Finally, we stress the importance of collecting independent evaluation data and suggest that, as with the training data, a systematic approach be used to ensure broad environmental coverage, rather than relying on a random selection of test sites.
Article
Summary1. Physical habitat is the living space of instream biota; it is a spatially and temporally dynamic entity determined by the interaction of the structural features of the channel and the hydrological regime.2. This paper reviews the need for physical habitat assessment and the range of physical habitat assessment methods that have been developed in recent years. These methods are needed for assessing improvements made by fishery enhancement and river restoration procedures, and as an intrinsic element of setting environmental flows using instream flow methods. Consequently, the assessment methods must be able to evaluate physical habitat over a range of scales varying from the broad river segment scale (up to hundreds of kilometres) down to the microhabitat level (a few centimetres).3. Rapid assessment methods involve reconnaissance level surveys (such as the habitat mapping approach) identifying, mapping and measuring key habitat features over long stretches of river in a relatively short space of time. More complex appraisals, such as the Physical Habitat Simulation System (PHABSIM), require more detailed information on microhabitat variations with flow.4. Key research issues relating to physical habitat evaluation lie in deciding which levels of detail are appropriate for worthwhile yet cost-effective assessment, and in determining those features that are biologically important and hence can be considered habitat features rather than simple geomorphic features.5. The development of new technologies particularly relating to survey methods should help improve the speed and level of detail attainable by physical habitat assessments. These methods will provide the necessary information required for the development of the two-and three-dimensional physical and hydraulic habitat models.6. A better understanding of the ways in which the spatial and temporal dynamics of physical habitat determine stream health, and how these elements can be incorporated into assessment methods, remains a key research goal.
Article
1.This paper reports on an extension to the use of Fluvial Audit survey to include a subjective and adaptive multi-criteria assessment (MCA) process that integrates scientific literature and observational data to develop three reach-scale indices of: (a) channel modification; (b) channel function (sediment store or source); and (c) naturalness. These indices are nested within an overall conceptual model of channel evolution and used to underpin catchment scale river restoration.2.The approach is described and applied to a small groundwater dominated river in the UK. The results show that over 48% of the total main river was in a degraded state relative to a conceptual model of a natural reference state. Only 23% of the river was in a near-natural state.3.MCA classifications were translated into a set of management actions necessary to return each reach to a near-natural condition. These are described.4.The method offers a transparent decision support for stakeholders that can incorporate differing scientific evidence. The use of MCA enables flexibility in terms of the relative importance of scores and weights placed upon factors in the final classification. This makes the approach amenable to stakeholder and public consultation. Copyright © 2009 John Wiley & Sons, Ltd.
Article
1. In the UK, Phase 1 survey is a standard method of habitat mapping that has been used widely for environmental assessment and management planning. In this paper we make the first rigorous test of the precision with which environmental consultants apply the technique. 2. Six ecologists surveyed independently the same upland site in northern England. In pairwise comparisons between maps, spatial agreement was found to average 25·6% (with a range of 17·3–38·8%) of the area of the study site. The numbers of land cover types that were identified ranged from 13 to 21. Four or more surveyors agreed on the classification of 19% of the study site, while the area of land upon which all six agreed was only 7·9% of the study site. Spatial errors in the positioning of habitat boundaries occurred, but were a relatively minor source of the differences between maps. The majority of differences between maps were due to classification errors. Land cover types with similar species compositions were most frequently confused. 3. Spatially referenced field ‘target notes’ giving additional information on the vegetation mapped in each survey varied in number between 18 and 56. The contents of target notes were inadequate to allow a retrospective assessment of mapping decisions. The total numbers of species listed in target notes varied between surveys from 25 to 145. Sorenson's similarity for species lists derived from pairs of surveys ranged from 18·8% to 63·7%, and was not related to spatial agreement between surveys. 4. Time spent at the field site was not a correlate of any aspect of the results or cost of the survey. Three surveys conducted by members of a professional institute for ecologists were the most expensive, and also recorded larger numbers of target notes and species than the other surveys. However, their maps were no more similar than other pairs of maps. 5. Analysis of the survey results and comparisons with other methods of vegetation mapping suggest that mapping precision could be increased by (i) placing a greater emphasis on use of aerial photographs and other extant map data prior to (and during) field work; (ii) making greater provision for mapping of mosaics and increasing the level of floristic information in habitat definitions; (iii) recording a greater number of more detailed target notes in the field; and (iv) providing office-based support to assist in the interpretation of aerial photographs, and the cross-checking of field surveyors’ preliminary classifications against the contents of target notes and habitat definitions. The current application of the Phase 1 approach by environmental consultants places too great a reliance on decision-making by the (frequently) unsupported lone surveyor whilst in the field.
Article
1.The River Styles® framework is a geomorphic approach to the classification of river types, assessment of the physical condition of rivers, and planning of physical rehabilitation. However, the linkages between River Styles and aquatic biodiversity conservation are still only weakly developed.2.In this study, 41 sites in the Bega River basin in New South Wales, Australia, were classified according to River Style and geomorphic condition, and surveyed for four biological assemblages: diatoms, aquatic and semi-aquatic macrophytes, aquatic macroinvertebrates and fish.3.Each assemblage differed significantly among River Styles. However, in the case of diatoms and fish, these differences could be accounted for by geographic clustering of sites in the same River Style, and a tendency for River Styles to occupy particular altitudinal zones and sizes of streams. This result was attributed to the overriding influences of water quality on diatoms and of altitude-related variation in water temperature and distance from the ocean on fish. For macrophytes and macroinvertebrates, geomorphic river type appeared to exert a direct influence, probably via variation in physical habitat characteristics.4.Geomorphic condition, judged as good, moderate or poor by reference to the inferred natural condition of each River Style, was also significantly associated with differences in biological assemblages other than fish. Twice as many taxa appeared to favour sites in good geomorphic condition as favoured sites in poor condition. Many of the taxa associated with sites in poor condition are alien taxa introduced to Australia since European settlement.5.These findings imply that protection of reaches that are in good geomorphic condition is likely to be critical for the maintenance of indigenous biodiversity, and that rehabilitation of geomorphic condition can assist in the rehabilitation of native riverine biota. Copyright © 2006 John Wiley & Sons, Ltd.
Article
  Although the term ``pebble count'' is in widespread use, there is no standardized methodology used for the field application of this procedure. Each pebble count analysis is the product of several methodological choices, any of which are capable of influencing the final result. Because there are virtually countless variations on pebble count protocols, the question of how their results differ when applied to the same study reach is becoming increasingly important. This study compared three pebble count protocols: the reach-averaged Environmental Monitoring and Assessment Program (EMAP) protocol named after the EMAP developed by the Environmental Protection Agency, the habitat-unit specific U.S. Forest Service’s PACFISH/INFISH Biological Opinion (PIBO) Effectiveness Monitoring Program protocol, and a data-intensive method developed by the authors named Sampling Frame and Template (SFT). When applied to the same study reaches, particle-size distributions varied among the three pebble count protocols because of differences in sample locations within a stream reach and along a transect, in particle selection, and particle-size determination. The EMAP protocol yielded considerably finer, and the PIBO protocol considerably coarser distributions than the SFT protocol in the pool-riffle study streams, suggesting that the data cannot be used interchangeably. Approximately half of the difference was due to sampling at different areas within the study reach (i.e., wetted width, riffles, and bankfull width) and at different locations within a transect. The other half was attributed to using different methods for particle selection from the bed, particle-size determination, and the use of wide, nonstandard size classes. Most of the differences in sampling outcomes could be eliminated by using simple field tools, by collecting a larger sample size, and by systematically sampling the entire bankfull channel and all geomorphic units within the reach.
A classification of channel-reach morphology in mountain drainage basins synthesizes stream morphologies into seven distinct reach types: colluvial, bedrock, and five alluvial channel types (cascade, step pool, plane bed, pool riffle, and dune ripple), Coupling reach-level channel processes with the spatial arrangement of reach morphologies, their links to hillslope processes, and external forcing by confinement, riparian vegetation, and woody debris defines a process-based framework within which to assess channel condition and response potential in mountain drainage basins, Field investigations demonstrate characteristic slope, grain size, shear stress, and roughness ranges for different reach types, observations consistent with our hypothesis that alluvial channel morphologies reflect specific roughness configurations adjusted to the relative magnitudes of sediment supply and transport capacity, Steep alluvial channels (cascade and step pool) have high ratios of transport capacity to sediment supply and are resilient to changes in discharge and sediment supply, whereas low-gradient alluvial channels (pool riffle and dune ripple) have lower transport capacity to supply ratios and thus exhibit significant and prolonged response to changes in sediment supply and discharge, General differences in the ratio of transport capacity to supply between channel types allow aggregation of reaches into source, transport, and response segments, the spatial distribution of which provides a watershed-level conceptual model linking reach morphology and channel processes, These two scales of channel network classification define a framework within which to investigate spatial and temporal patterns of channel response in mountain drainage basins.
Article
1. Rivers are subject to thresholds of several types that define significant changes in processes and morphology and delimit distinctive riverine landscapes and habitats. Thresholds are set by the conditions that govern river channel process and form, amongst which the most important are the flow regime, the quantity and calibre of sediment delivered to the channel, and the topographic setting (which determines the gradient of the channel). These factors determine the sediment transport regime and the character of alluvial deposits along the channel. 2. Changes occur systematically along the drainage system as flow, gradient and sediment character change, so a characteristic sequence of morphological and habitat types - hence of riverine landscapes - can be described from uplands to distal channels. The sequence is closely associated with stream competence to move sediment and with bank stability. 3. The paper proposes a first order classification of river channel and landscape types based on these factors. The riverine landscape is affected seasonally by flow thresholds, and further seasonal thresholds in northern rivers are conditioned by the ice regime. 4. It is important to understand geomorphic thresholds in rivers not only for the way they determine morphology and habitat, but because human activity can precipitate threshold crossings which change these features significantly, through either planned or inadvertent actions. Hence, human actions frequently dictate the character of the riverine landscape.
Article
A classification system for natural rivers is presented in which a morphological arrangement of stream characteristics is organized into relatively homogeneous stream types. This paper describes morphologically similar stream reaches that are divided into 7 major stream type categories that differ in entrenchment, gradient, width/depth ratio, and sinuosity in various landforms. Within each major category are six additional types delineated by dominate channel materials from bedrock to silt/clay along a continuum of gradient ranges. Recent stream type data used to further define classification interrelationships were derived from 450 rivers throughout the U.S, Canada, and New Zealand. Data used in the development of this classification involved a great diversity of hydro-physiographic/geomorphic provinces from small to large rivers and in catchments from headwater streams in the mountains to the coastal plains. A stream hierarchical inventory system is presented which utilizes the stream classification system. Examples for use of this stream classification system for engineering, fish habitat enhancement, restoration and water resource management applications are presented. Specific examples of these applications include hydraulic geometry relations, sediment supply/availability, fish habitat structure evaluation, flow resistance, critical shear stress estimates, shear stress/velocity relations, streambank erodibility potential, management interpretations, sequences of morphological evolution, and river restoration principles.
Book
Applied Spatial Data Analysis with R, second edition, is divided into two basic parts, the first presenting R packages, functions, classes and methods for handling spatial data. This part is of interest to users who need to access and visualise spatial data. Data import and export for many file formats for spatial data are covered in detail, as is the interface between R and the open source GRASS GIS and the handling of spatio-temporal data. The second part showcases more specialised kinds of spatial data analysis, including spatial point pattern analysis, interpolation and geostatistics, areal data analysis and disease mapping. The coverage of methods of spatial data analysis ranges from standard techniques to new developments, and the examples used are largely taken from the spatial statistics literature. All the examples can be run using R contributed packages available from the CRAN website, with code and additional data sets from the book's own website. Compared to the first edition, the second edition covers the more systematic approach towards handling spatial data in R, as well as a number of important and widely used CRAN packages that have appeared since the first edition. This book will be of interest to researchers who intend to use R to handle, visualise, and analyse spatial data. It will also be of interest to spatial data analysts who do not use R, but who are interested in practical aspects of implementing software for spatial data analysis. It is a suitable companion book for introductory spatial statistics courses and for applied methods courses in a wide range of subjects using spatial data, including human and physical geography, geographical information science and geoinformatics, the environmental sciences, ecology, public health and disease control, economics, public administration and political science. The book has a website where complete code examples, data sets, and other support material may be found: http://www.asdar-book.org. The authors have taken part in writing and maintaining software for spatial data handling and analysis with R in concert since 2003.
Article
The particle size of the bed sediments in or on many natural streams, alluvial fans, laboratory flumes, irrigation canals and mine waste deltas varies exponentially with distance along the stream. A plot of the available worldwide exponential bed particle size diminution coefficient data against stream length is presented which shows that all the data lie within a single narrow band extending over virtually the whole range of stream lengths and bed sediment particle sizes found on Earth. This correlation applies to both natural and artificial flows with both sand and gravel beds, irrespective of either the solids concentration or whether normal or reverse sorting occurs. This strongly suggests that there are common mechanisms underlying the exponential diminution of bed particles in subaerial aqueous flows of all kinds. Thus existing models of sorting and abrasion applicable to some such flows may be applicable to others. A comparison of exponential laboratory abrasion and field diminution coefficients suggests that abrasion is unlikely to be significant in gravel and sand bed streams shorter than about 10 km to 100 km, and about 500 km, respectively. Copyright (C) 1999 John Wiley & Sons, Ltd.
Article
Geostatistics is essential for environmental scientists. Weather and climate vary from place to place, soil varies at every scale at which it is examined, and even man-made attributes - such as the distribution of pollution - vary. The techniques used in geostatistics are ideally suited to the needs of environmental scientists, who use them to make the best of sparse data for prediction, and top plan future surveys when resources are limited. Geostatistical technology has advanced much in the last few years and many of these developments are being incorporated into the practitioner's repertoire. This second edition describes these techniques for environmental scientists. Topics such as stochastic simulation, sampling, data screening, spatial covariances, the variogram and its modeling, and spatial prediction by kriging are described in rich detail. At each stage the underlying theory is fully explained, and the rationale behind the choices given, allowing the reader to appreciate the assumptions and constraints involved.
European waters -assessment of status and pressures
European Environment Agency, 2012. European waters -assessment of status and pressures, p. 100.
A guidance standard for assessing the hydromorphological features of rivers
CEN, 2004. A guidance standard for assessing the hydromorphological features of rivers., in: Comité Européen de Normalisation (Ed.).
Extending the evidence base on the ecological impacts of fine sediment and developing a framework for targeting mitigation of agricultural sediment losses
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Collins, A.L., Jones, J.I., Sear, D.A., Naden, P.S., Skirvin, D., Zhang, Y.S., Gooday, R., Murphy, J., Lee, D., Pattison, I., Foster, I.D.L., Williams, L.J., Arnold, A., Blackburn, J.H., Duerdoth, C.P., Hawczak, A., Pretty, J.L., Hulin, A., Marius, M.S.T., Smallman, D., Stringfellow, A., Kemp, P., Hornby, D., Hill, C.T., Naura, M., Brassington, J., 2014. Extending the evidence base on the ecological impacts of fine sediment and developing a framework for targeting mitigation of agricultural sediment losses. Defra report WQ128, Defra ed. Defra.
Applied fluvial geomorphology for river engineering and management
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Thorne, C.R., 1997. Channel types and morphological classification. Applied fluvial geomorphology for river engineering and management, 175-222.
National Risk Assessments for Morphology: Broad-Scale Evaluation
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Downstream fining in a gravel bed river in Southern Poland: Lithological controls and the role of abrasion
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Werritty, A., 1992. Downstream fining in a gravel bed river in Southern Poland: Lithological controls and the role of abrasion, in: P., B., R.D., H., C.R., T., P., T. (Eds.), Dynamics of Gravel Bed Rivers. Wiley: Chichester, pp. 333-346.
Living Planet Report 2014. Species and spaces, people and places
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