bluuebunny/crossref_metadata_2025_split huggingface dataset:
Development of habitat suitability criteria for trout in small streams
Authors: Lambert Thomas R. , Hanson David F. 
Published: February 2007

AbstractWe observed 2863 trout in the wild to determine habitat utilization in small streams of the Kings River basin in California's Sierra Nevada mountains. The habitat utilization data were used to develop habitat suitability functions that provide input variables to the instream flow incremental methodology (IFIM) habitat assessment model of the U.S. Fish and Wildlife Service.Observations of habitat utilization of rainbow trout (Salmo gairdneri), brown trout (Salmo trutta), and brook trout (Salvelinus fontinalis) were obtained during the summer months of 1983 and 1984. The observations were made in small streams with discharges ranging from 0.7 m3 s−1 to 0.03 m3 s−1. The streams are at elevations of 1250 to 2530 m. Equal effort was applied to observing undisturbed trout in all habitat types. Snorkeling proved to be the most effective method of observation.Individual trout of all species and life stages were most often observed in the lower half of the water column, utilizing low‐velocity currents of less than 3.0 cm s−1.From the depth and velocity utilization data, several forms of habitat suitability functions were developed and evaluated:

Univariate depth and velocity functions derived from frequency histogram analysis.
Univariate depth and univariate velocity exponential polynomial models.
Bivariate depth and velocity exponential polynomial models.
Univariate exponential polynomial models provided the best fit to the data for each species, based on visual comparisons of response surfaces and contour plots, and comparisons of computed sums of squared errors. Bivariate models fitted to the data resulted in greater sums of squared errors than multiplicative aggragation of univariate models, and frequently predicted utilization at zero depth.The habitat suitability functions derived from the univariate exponential polynomial models provided the best input to the IFIM habitat assessment models.
Influence of river regulation on nitrogen and phosphorus mass transport in a large south American river
Authors: Pedrozo F. , Bonetto C. 
Published: February 2007

AbstractThe Paraná upper reaches, above the confluence with the Paraguay River, drains a predominantly humid, tropical‐subtropical basin that has been extensively altered by anthropogenic activities. Deforestation followed by intense mechanized agriculture has progressively increased in the last decades. Many industrial settlements and hydroelectric impoundments have been developed. Suspended matter, total phosphorus, and inorganic nitrogen exportation rates were estimated at 14 t km−2 y−1, 28kg TP km−2 y−1 and 188kg N km −2 y−1 respectively. These rates are compartively low when compared to other areas of the world. It was estimated that riverine mass transport represented roughly 6 per cent of the phosphorus and 20 per cent of the nitrogen inputs in the basin. Mass transport of suspended matter and soluble reactive phosphorus are lower and inorganic nitrogen higher than in 1967–1969. Siltation in the man‐made lakes reduced both suspended matter and phosphorus transport. Inorganic nitrogen increase is thought to be related to increased fertilizer inputs.
River wildlife databases and their value for sensitive environmental management
Authors: Coles T. F. , Southey J. M. , Forbes I. , Clough T. 
Published: February 2007

AbstractA survey over a 3‐year period, which commenced in 1987, of the plant and bird communities along 1200 km of river in Lincolnshire and South Humberside, Eastern England, is described. Analysis of data from 247 km of river recorded a great diversity of wildlife, comprising 570 species of plant and 80 species of breeding birds. The management value of such surveys is discussed and these include the preparation of detailed maps of each 500m section of river, which illustrate the habitat structure, and plant and bird communities. A maintenance procedure for each 500 m section of river is then agreed between conservation and operations personnel, preventing areas of wildlife importance from being accidentally destroyed. An index which combines both the diversity and rarity of the plant and bird communities is proposed as a measure of conservation importance. This index allows sections of river to be graded according to their conservation value into one of five groups. The surveys also enable predictions to be made of the effects of management actions on the wildlife and provide information by which fundamental reviews of operational activities can be carried out.
Organic matter transport and retention in a blackwater stream recovering from flow augmentation and thermal discharge
Authors: Hauer F. Richard 
Published: February 2007

AbstractOrganic and inorganic seston, benthic organic matter and woody debris were studied in a blackwater stream/floodplain system recovering from flow augmentation and thermal discharges. The stream had received cooling waters from two nuclear reactors from the mid‐1950s to 1968, resulting in flows over 10x greater than normal and temperatures that exceeded 70°C. Channel morphology was markedly altered, woody debris was removed or buried, and floodplain vegetation was destroyed. Fifteen years after termination of cooling water discharges, the stream continued to exhibit many characteristics of a disturbed system. Compared to an undistributed reference stream, the recovering stream had substantially less benthic organic matter, fewer snags and debris dams, and transported more organic and inorganic seston of all size fractions examined. Because of the importance of these biophysical factors in the structural morphology of blackwater streams, it is hypothesized that complete recovery will not be realized until the floodplain forest has matured and large woody debris is contributed to the stream channel.
Environmental stability and communities of chironomidae (diptera) in a regulated river
Authors: Armitage P. D. , Blackburn J. H. 
Published: February 2007

AbstractChanges in the faunal composition and density of communities of chironomid larvae were studied over a four year period in a newly regulated stream and compared with those in an adjacent unregulated stream, with a view to examining “stability” in contrasting environments. A total of 68 chironomid taxa were recorded from all sites. Faunal diversity was lowest closest to the dam and highest in the unregulated site. Within the study period values of H were highest in the fourth year of study (five years after dam closure). Species increments were tending to level out at the three totally regulated sites whereas at the partially regulated and unregulated sites new taxa continued to be recorded in samples.Clustering techniques and similarity indices clearly separated the study sites based on the composition of the chironomid fauna and there were indications that the unregulated sites were more variable in faunal composition between years than the regulated sites. The data are used to develop a conceptual model of fluctuations in faunal parameters under steady or reduced flow regimes. It is suggested that environmental stability brought about by regulation has structured the composition of the chironomid community and further that the changes occur very rapidly after impoundment. The model identifies key areas of faunal change and the question of environmental stability is discussed in relation to the scale of observation.
The legal framework for river use in the United States
Authors: Cox William E. 
Published: February 2007

AbstractUse and development of rivers takes place within a complex legal framework that guides the actions of interested parties holding conflicting values. One of the major components of this legal framework is state water allocation law. This law takes several forms among the states, but its basic function is to establish rules for water use by assigning property rights in water. Another component of the legal framework for river use addresses the public access issue. The primary focus here is establishment of the boundary between the exclusive rights of landowners and the rights of the general public to use the surface and underlying beds of waterways. A third component consists of governmental controls over water use and development. These controls restrict the exercise of private property rights in the resource. From an initial focus of protecting the public right of navigation, this law has expanded to include protection of water quality and a variety of other environmental values. The current legal framework provides a relatively sound basis for balancing competing values and interests, but problems exist. For example, the division of water management responsibilities between the federal and state levels of government sometimes results in conflict, and existing procedures for managing conflict related to proposals for water transfer do not appear to be adequate. Therefore, the current framework will not remain static; it must continue to evolve in order to operate more effectively and to incorporate future increases in knowledge and the associated changes in values and management needs.
Juvenile fishes as functional describers of fluvial ecosystem dynamics: Applications on the river rhǒne, France
Authors: Copp G. H. , Oliver J. M. , Peňáz M. , Roux A. L. 
Published: February 2007

AbstractBiological indicators may signal changes in freshwater quality but offer little information on long‐term trends in ecosystem succession. As an improvement over biological indicators in river management we propose the use of ‘functional describers’, abiotic and biotic elements that reflect alterations in ecosystem function and succession through changes in their concentration or abundance, including the appearance and/or extinction of organisms or groups of organisms. Juvenile (0 +) fishes have been found to be useful functional describers in many fluvial situations encountered in Europe, not least because the ontogeny of European fishes is strongly reflected in the type of habitat chosen for reproduction. Using the regulated River Rhǒne, France, as an example, the absence or presence of 0 + juveniles is shown to provide a direct reflection of a biotope's potential as a spawning area, particularly if recent hydrological conditions have not facilitated 0 + fish displacement and the lone presence of a predator species has not suggested the elimination of other fish species. Identification of the ecological function and successional state of a fluvial ecosystem is aided by consideration of species reproductive styles and tolerances. When time, labour, and/or funding is limited, the function and succession of numerous biotopes within a catchment or large fluvial system can be monitored cost effectively by analysing the 0 + fishes assemblages via the functional describer approach.
Depth distribution and mobility of a harpacticoid copepod within the bed sediment of an alpine brook
Authors: Verena Kowarc A. 
Published: February 2007

AbstractThe harpacticoid copepod Limnocamptus echinatus (Mrazek) shows a very distinct large‐scale vertical distribution within the bed sediments of Oberer Seebach, a second‐order gravel stream. The population peak appears in a sediment layer between 15 and 35 cm over long periods on average. Abundances are significantly lower in the topmost sediments and sediment layers below 50 cm depth. The large‐scale vertical distribution is mainly influenced by the changes and pattern of temperature and discharge, which influences the current velocity of the surface and interstitial water. Effects appear quite different, when permanent flooded areas and areas that periodically fall dry on the surface are compared. Limnocamptus echinatus is forced deeper into the sediments of the gravel bar during low water temperatures and/or high discharge situations. On permanent flooded areas the vertical distribution is more stable over long periods, but higher fluctuations occur during short periods. The Limnocamptus echinatus population shows higher mobility in deeper sediment layers (40 to 60 cm sediment depth). Comparing longer periods, water flow and the transport of fine material differ in deeper sediment layers. The water current is much slower, producing a tendency for fine material sedimentation. This might be the main reason for the higher mobility in deeper sediment layers and the restriction of 90 per cent of the Limnocamptus echinatus population to a sediment depth of 50 cm. High mobility in vertical and horizontal directions within the bed sediments is interpreted as normal reactions and adaptations to the dynamic behaviour of the system, mainly forced by physical parameters. Biological parameters appear as subdominant for large‐scale vertical distributions.
Oligochaete worms as biological describers of the interactions between surface and groundwaters: A first synthesis
Authors: Lafont M. , Durbec A. , Ille C. 
Published: February 2007

AbstractThe paper focuses on the definition of the vulnerability of phreatic waters to surface water pollution. The amplification of water exchanges between surface and underground waters, because of human activities, is considered as a risk of contamination of aquifers. The aim of this paper is to present a first synthesis of oligochaetes as biological describers of these exchanges.Field investigations have shown that several rare and/or stygophilous taxa are found in surface (coarse) sediments of rivers upstream and/or downstream of dams or gravel operations. These observations relate to species such as Propappus volki, Pristina spp., Chaetogaster parvus, Rhyacodrilus carsticus, R. falciformis, Phallodrilus spp. The data suggest that these species invade surface waters from phreatic or interstitial waters when water flows are amplified between the two. Flow amplification is considered as a consequence of dams' and gravel operations' hydraulic impact. But the lack of hydraulic validation of the presumed active exchanges describer's (AED) ecological status given to those species remains a problem, giving the opportunity to examine the link between hydraulics and biology.Preliminary results on two gravel pits of La Wantzenau (Rhine alluvial valley, France) have shown relations between the distribution of oligochaetes, especially Lumbriculidae, and soil filtration properties. Two other studies were planned along an industrially polluted tract of the River Rhǒne (Grand Gravier Island). Horizontal and vertical zonation of the river banks were performed by studying simultaneously hydraulics and oligochaetes. Preliminary results have shown that the absolute and relative abundances of taxa such as Phallodrilus sp. and S. velutinus increase in relation to the permeability of superficial coarse substrate in the horizontal plane, and to the current velocity in underground porous media in the vertical plane. The increasing percentages of P. barbatus and the decreasing percentages of Tubificidae reveal active exchange zones where superficial waters are renewed by groundwaters. Some other species such as P. vejdovskyi seem to be potential describers of water exchanges.
Spatial and temporal variations of niphargus populations in interstitial aquatic habitat at the karst/floodplain interface
Authors: Essafi Khadija , Mathieu Jacques , Beffy Jean‐Luc 
Published: February 2007

AbstractArtificial substrates buried in stream sediments at the karst/floodplain interface were used to examine the spatial and temporal variations of Niphargus populations. The study was carried out at two stations in two different areas of the French Jura. One was mainly supplied by karst water (Verna station), the other by both karst and surface waters (Pissoir station). The occupation of interstitial habitat was found to depend on several interacting factors:
The waterflow and its changes at the outlet. The correlation between abundance of individuals and discharge was strongest with the discharges two to four days before sampling. The structure and restoration of populations after a spate related to geological characteristics. In particular, restoration was slower and more difficult in the sediments located at the base‐level of a massif (Verna) than at an overflow level (Pissoir).
The location of the sediments. At the Pissoir station, the number of individuals was higher at the main outflow, but also for both stations, on the banks opposite the outlet. Animals drifting from the karst system found refuge in the sediment of the opposite bank. Almost no Niphargus were found upstream from the outlets. At the Verna station, Niphargus were only found inside the cave.
The variability of the number of animals at different depths in the sediment was more difficult to explain. At the station mainly supplied by karst water, which presented a relatively constant flow during the study, the distribution seemed to be random. At the other station, where discharge varied considerably, the vertical distribution globally presented a gradient in abundance with more individuals in the upper sediment level. This gradient varied according to the samples. Discharge changes partly explained these results.
A floodplain spring: An ecotone between surface water and groundwater
Authors: Plenet S. , Gibert J. , Vervier P. 
Published: February 2007

AbstractEcotones may be viewed as boundaries separating adjacent resource patches. They are dynamic components of the aquatic landscape and in the alluvial floodplain they occur as both diffuse and concentrated zones between surface and groundwater environments. This study is focused on a floodplain spring whose water supplies a backwater of the upper Rh6ne River alluvial floodplain (Iles Nouvelles). This paper analyses the community structure on both sides of the physical boundary separating the two ecosystems in relation to hydrological characteristics. The contact between two different environments (surface water and water‐saturated sediment) creates a physical discontinuity which is of great importance for the distribution of aquatic fauna. Two types of organization are described: (1) within the sediment body there are mixed communities (epigean and hypogean) which can move with hydrological variations (biological ecotone) and (2) within the surface‐water body there is a typical epigean fauna which displays a ‘border effect’. The ecological implications of the various patterns of biological responses are discussed as well as the regulatory aspect of the ecotone which minimizes the washout of hypogean fauna towards the surface ecosystem.
An approach to the synthesis of qualitative ecological information from aquatic coleoptera communities
Authors: Bournaud Michel , Richoux Philippe , Usseglio‐Polatera Philippe 
Published: February 2007

AbstractA list of 196 Coleoptera taxa, larvae and adults, covering 113 species, was obtained from several surveys of a flood plain of the Rhô river. From published reports and personal experience, each taxon is linked with the modalities of nine environmental and three biological variables. The resulting 12 ecological profiles for 196 taxa are analysed by correspondence analysis. The simultaneous ordination of the taxa and variables allows presentation of the more synthetic correspondence between the Coleoptera and their ecological and biological characteristics. The niche dimensions of the 12 variables tested here are organized along a current‐substrate gradient, from stones in rapid flow to mud in still water, which is associated with the other ecological conditions. This ordination reflects environmental conditions in a transverse direction, particularly from the central channel to the furthest annexes of the river. The Coleoptera are shown to be describers of the connectivity with the main channel. The 196 studied taxa are positioned along the gradient. They are subdivided into seven faunal groups based on their habitat range or niche width. The larger species are confined to the stagnant side of the gradient. Other variables, such as feeding and vertical distribution, clearly separate carnivores from herbivores and also larvae from adults. The next step of this study will be to extend these investigations to other functional variables and to all the species of Coleoptera in France. The information given by the Coleoptera will then be compared with actual field measurements.
Distribution, abundance and development of trichoptera larvae in the river north tyne following the commencement of hydroelectric power generation
Authors: Boon P. J. 
Published: February 2007

AbstractFollowing turbine installation at the Kielder dam, the River North Tyne downstream is now characterized by large daily fluctuations in flow. A survey of trichopteran populations (Hydropsychidae, Rhyacophilidae and Polycentropodidae) was carried out to assess the impact of hydroelectric power generation (Phase III), and to compare the results with similar pre‐impoundment (Phase I) and post‐impoundment (Phase II) surveys. Benthic samples were collected quarterly upstream from the reservoir and at four stations downstream. Although the same three species (Hydropsyche siltalai, Hydropsyche pellucidula and Rhyacophila dorsalis) continue to dominate, there were some notable differences found between sampling sites. Species diversity was drastically reduced at the station nearest the dam, where 99% of all larvae collected were R. dorsalis. At the next station 5 km downstream, where previously H. siltalai had been dominant, R. dorsalis now constitutes 65% of collections. At the two stations farthest away from the dam the former prevalence of H. siltalai was re‐established. It is suggested that the unstable, high flows at the reservoir outlet are likely to favour the predatory R. dorsalis rather than the filter feeding hydropsychids whose nets may be susceptible to damage. Upstream from Kielder Water, R. dorsalis was prominent in benthic samples, whereas numbers of H. siltalai were 10 times lower than in Phase II and 60 times lower than in Phase I. The extent to which such upstream changes may be related to altered patterns of community structure below the dam is not known, but these observations may warrant a more cautious approach when considering upstream areas as unaffected ‘reference sites’. Instar analyses suggested that winter‐warm, summer‐cool discharges were continuing to modify larval growth rates, as noted in Phase II. The results of this study are discussed in relation to present trends in water resource development in Britain, especially with regard to future needs in monitoring and research.
Instream flow models for mixed deciduous riparian vegetation within a semiarid region
Authors: Stromberg J. C. 
Published: February 2007

AbstractEmpirical evidence from a semiarid watershed of the southwestern United States (Verde River basin, Arizona) indicated that abundance and species richness of mixed deciduous riparian forests varied in a curvilinear and quantifiable fashion as a function of stream flow parameters. Three indicators of riparian abundance—foliage area, stem basal area and stand width—increased most significantly with growing season flow volume, a surrogate indicator of riparian water availability. Tree species richness varied in a bell curve fashion with flood size, with the greatest richness occurring at streams with intermediate flood magnitudes. These instream flow models have management implications for riparian habitats. They suggest that flow volume (and the related attributes of water‐table recharge and floodplain soil wetting) is the primary factor regulating riparian vegetation abundance in the Verde River watershed, and provide a first approximation of the extent of riparian loss expected from flow diversion or other types of flow reduction.