bluuebunny/crossref_metadata_2025_split huggingface dataset:
Physicochemical factors affecting larval fish densities in mississippi river floodplain ponds, Louisiana (U.S.A.)
Authors: Sabo Matthew J. , Kelso William E. , Bryan C. Frederick , Rutherford D. Allen 
Published: February 2007

AbstractWe collected water‐quality data from 15 artificial floodplain ponds along the Mississippi River during May 1988 and quantified shoreline length, shoreline sinuousity, volume, and depth variation. Ponds regarded as high‐quality nurseries (based upon larval fish densities) contained higher dissolved oxygen concentrations and lower total organic carbon concentrations than ponds of lower nursery quality (p < 0.02). High‐quality nurseries also maintained higher conductivity and turbidity than low‐quality nurseries (p < 0.05). Results indicated that dissolved oxygen and pH probably fluctuated less in high quality nurseries and therefore provided better conditions for survival and growth of larval fishes. Total organic carbon and conductivity were directly related to pond morphometry (p < 0.004) and affected dissolved oxygen and pH in ponds. Large, high‐volume ponds with sinuous shorelines and variable depths tended to contain both high conductivities and low total organic carbon concentrations. Pond morphometry may have affected water quality and subsequently determined the nursery value of artificial floodplain ponds.
Typology of aquatic habitats in the great ouse, a small regulated lowland river
Authors: Copp Gordon H. 
Published: February 2007

AbstractA study of aquatic habitat types was undertaken in August 1989 on the River Great Ouse. Habitat character at 44 sites was evaluated via twelve qualitative and quantitative environmental variables. Discriminant Analysis of the environmental data revealed a weak discrimination of sites corresponding with longitudinal changes in channel width. Distinction between the habitat types in the analysis was relatively weak. Compared with unregulated European lowland rivers of similar geomorphological origin, the Great Ouse possesses little transversal habitat diversity (abandoned channels, oxbows, etc.) and the ponding effect of water retention structures in downstream sections appears to have created a slight longitudinal gradient in channel width and depth. This comparatively low habitat heterogeneity corroborates a previous report of limited recruitment in the Great Ouse by 0 + fishes of both limnophilous and rheophilous reproductive guilds, with a predominance of generalist spawners.
Macroinvertebrate assemblages in floodplain habitats of the lower river murray, South Australia
Authors: Boulton A. J. , Lloyd L. N. 
Published: February 2007

AbstractMacroinvertebrates were sampled in seven microhabitats (submerged woody debris, reeds, sedges, inundated grass, floating aquatic vegetation, lignum, and the unvegetated littoral) at thirteen sites representing six macrohabitats (single temporary and permanent ox‐bow lakes (billabongs), fast and slow‐flowing anabranches, backwaters, and the main channel) of the River Murray, and Australian lowland river. Sites were sampled in spring 1988, shortly after floodwaters had receded.Most of the 95 taxa collected were aquatic insects. Detritivores were most abundant in all macrohabitats except the temporary billabong where predators predominated. Scrapers were only abundant in the permanent billabong. The temporary billabong harboured the most species and individuals whereas slowly‐flowing anabranches contained the fewest species and individuals. At the microhabitat level, most taxa and individuals occurred in stands of aquatic vegetation. The unvegetated littoral zone was the most depauperate microhabitat.Multivariate analyses illustrated the distinctiveness of the faunal assemblage found in the temporary billabong. Subsequent analyses of the permanently inundated macrohabitats indicated gradients related to current velocity and the extent to which the sites were continuous with the main river. Current velocity apparently determined assemblage composition at the macrohabitat scale whereas the structural complexity of submerged vegetation operated at the microhabitat scale.The relatively large number of taxa collected from this area emphasizes the importance of a range of macrohabitats and microhabitats to faunal diversity in a floodplain ecosystem. Although there was little faunal overlap between billabongs and the main river, billabongs probably serve as refuges for many lentic taxa that rely upon regular inundation to survive. Surveys of floodplain rivers for management purposes must include samples from aquatic habitats adjacent to the main channel because the fauna of the floodplain is potentially most threatened by regulation and alteration of the flooding regime.
Grasshoppers (Orthoptera, Saltatoria) on alpine and dealpine riverbanks and their use as indicators for natural floodplain dynamics
Authors: Reich Michael 
Published: February 2007

AbstractGravel banks with sparse vegetation are typical habitats of braided alpine and dealpine floodplains. They are not only habitats for semiaquatic or hygrophilous organisms, but include also xerophilous elements: 17 species of grasshoppers were recorded in the floodplain of the Upper Isar (Bavaria, FRG). In the alpine region, two species (Bryodema tuberculata, Chorthippus pullus) occur only in floodplains, colonizing young gravel banks with sparse vegetation. Population dynamics and habitat selection of Bryodema tuberculata, studied on the Upper Isar for several years, are characterized by small scale movements of marked individuals between neighbouring gravel banks and fluctuations of the abundance on different sections of the gravel banks. Furthermore, the periodic desiccation of small watercourses is important for the dispersal of the females by walking. Historically widespread, today its distribution corresponds to the few remaining inundation areas. The main causes of decrease and extinction in most localities are man‐made changes in floodplain dynamics. The building of retention reservoirs and the diverting of streams for hydropower influenced succession in the downstream floodplains. Most of the gravel banks with sparse vegetation changed into willow thickets or pine forests. All remaining inundation areas should be protected. Bryodema tuberculata is a good indicator for the balance between progressing succession and the reorganization of gravel banks by floods.
A floodplain forest mosquito community after man‐made moisture changes (Culicidae, Diptera)
Authors: Vaňhara Jaromír 
Published: February 2007

AbstractThis paper summarizes data on the response of mosquitoes to changed water regime following extensive water management alterations on the southern Moravian Dyje and Morava rivers. Maximum groundwater level dropped by an average of 90 cm, previous regular floods were prevented, and the area covered by floodplain forests was significantly decreased due to the construction of three reservoirs.The original mosquito community of temporary water bodies (Aedes) is in retreat both quantitatively and, in places, qualitatively. Of the initial number of six species causing plagues, only Ae. vexans has remained (63.3 per cent), the rest occurring at percentages of only 0.1–4.1 per cent. After flood regulation, the breeding grounds of the species developing in temporary water bodies has filled only during periods of sufficiently high groundwater levels and sufficient saturation of soil with rainfall.A prospective group in this area includes mosquito species developing in permanent water bodies (Culex, Anopheles, Culiseta, etc.). This group is increasing in numbers and species richness. After the completion of three reservoirs, Anopheles spp. spread throughout the study area. They develop in the waters accompanying the reservoirs, especially in channels rich in vegetation, in which they attain densities of up to 39.9 larvae per 100 cm2 water surface. The drier environment, and drier and warmer climate prevailing in recent years have probably influenced the occurrence of southern species in the area, notably Culex martinii and Uranotaenia unguiculata.Long‐term quantitative collections of mosquitoes enable first note to be made on the possible fluctuation mechanisms, previously obscured by the essential influence of floods on community development.
Variations of the hyporheic zone through a riffle in the r. morava, Czechoslovakia
Authors: Štěrba Otakar , Uvíra Vladimír , Mathur Praveen , Rulík Martin 
Published: February 2007

AbstractWe observed the dynamic changes in the hyporheic zone, both in the vertical (0‐80 cm) and horizontal directions. Two stations with different hydrological conditions were compared, and subsequently related to two basic processes: infiltration of surface water into the sediments of the river bottom and repeated entry back to the surface stream. By comparing these two locations we attempted to show the existence of a continuous exchange of water between the surface of the river and the hyporheic zone in a process which we call ‘small bottom circulation’. At the same time, we also attempted to demonstrate that this process involves the self‐purification of the infiltrated water. We presume that self‐purification is realized both by means of physical processes (filtration, sedimentation and deposition) and by the biological decomposition of organic matter. Self‐purification of the infiltrated water between the stations which were compared are proved, above all, by the values of O2, BOD, COD, FPOM + CPOM, pH and conductivity. There are also remarkable differences in the qualitative composition in the macroinvertebrate community.
Vertical distribution of fauna in the bed sediment of three running water sites: Influence of physical and trophic factors
Authors: Maridet Laurence , Wasson Jean‐Gabriel , Philippe Michel 
Published: February 2007

AbstractRelationships between invertebrates, substrate characteristics and trophic factors were investigated, with special emphasis on the hyporheic habitat, in order to characterize the functioning of different running waters ecosystems.Three contrasting study sites were chosen in catchments exhibiting different features: (1) a meandering reach of the Loire River in its alluvial floodplain, upstream of the ‘Bec d'Allier’; (2) a reach of the Galaure with a fairly developed riparian corridor, a small sinuous foothill river; and (3) a braided reach of the Drac, an alpine torrential stream.Each site was sampled once using the freezing‐core technique with previous electro‐positioning of the invertebrates. In each site, four 60 cm cores were extracted, each one from different morphodynamic units.In the Loire and Galaure rivers, most invertebrates are found in the first 15 cm of the sediment, with the exception of some particular taxa or morphodynamic units (riffle head). Conversely, in the Drac lotic units, maximum density of invertebrates occurs between 15 and 30 cm and more than 75 per cent of all organisms are found at a depth > 15 cm. The vertical distribution of organisms does not follow a uniform pattern in different streams.In the substrate, the vertical distribution of macroinvertebrates is very closely related to porosity in contrast with trophic parameters that always decrease with depth. The porosity is negatively correlated with the percentage of sand in the sediment and seems to be important in determining the vertical distribution of fauna, and should be integrated in a functional typology of running waters.The trophic parameters and the structure of invertebrate community with its dominant feeding groups allow discrimination of the different sites.
Spatial distribution of interstitial assemblages in the floodplain of the rhǒne river
Authors: Marmonier P. , Dole‐Olivier M. J. , Creuz Chǎtelliers M. É Des 
Published: February 2007

AbstractInterstitial invertebrate assemblages of the Rhǒne River were studied at the scale of the entire alluvial plain. Ten stations, located in five former channels, were sampled with a Bou‐Rouch pump at 50 and 100 cm depth. The chemical characteristics of the interstitial water allowed the differentiation of stations without hydrological connections with the subterranean habitats, stations fed by surface water coming through the bank sediments and stations fed by true groundwater. The faunal assemblages reflect the difference between connected and isolated stations but did not demonstrate any differences related to the origin of the water. In fact the interstitial assemblages are distributed along a gradient from the margin of the floodplain (stations with a high physical stability associated with the absence of flood periods) to the area close to the main channel regularly influenced by floods. These results demonstrate that both groundwater characteristics and the position of the station in the floodplain influence the spatial distribution of interstitial fauna in the alluvial valley of the Rhǒne River.
Spring ecotone and gradient study of interstitial fauna along two floodplain tributaries of the river rhǒne, France
Authors: Chafiq Mohamed , Gibert Janine , Marmonier Pierre , Dole‐Olivier Marie‐José , Juget Jacques 
Published: February 2007

AbstractThe hyporheic zone of two small tributaries of the upper Rhǒne River where they cross the floodplain (approximately 2 km wide) was studied. The streams originate in karstic areas which directly border the floodplain. The surveys were conducted at 11 sites along the course of the two tributaries at a depth of 50 cm in bed sediments. Ten litre samples were collected six times a year with a Bou‐Rouch sampler. The paper examines the distribution of interstitial communities along two transverse (floodplain) profiles, defines the spring ecotone, analyses the heterogeneity, and underlines the importance of the tributaries in the functioning of the floodplain.A comparison between the spatial distributions of fauna and organic matter content along the two profiles underlines the important relationships between the groundwater and surface environment, and makes it possible to differentiate parts of the floodplain where the exchanges are most intense (interstitial spring, karst/floodplain interface). Along the longitudinal course of these streams, we observe the influence of groundwater circulation on community structure/i.e. the interactions between stream channel, alluvial aquifer and adjacent karstic aquifer.
Colonization of periodically inundated interstitial habitats of an alluvial pond by invertebrates
Authors: Tabacchi Eric 
Published: February 2007

AbstractThe interstitial fauna of an alluvial pond on the floodplain of the Adour River, South‐west France was sampled over a period of 13 months. The pond was connected to the adjacent river through phreatic flow and its water level varied in an annual cycle related to the level of the river. Monthly samples were taken from fixed points along five transects across the pond. The littoral zone was sampled between +20 and −80 cm from the substrate surface. From the seasonal variations in the distribution and abundance of invertebrates, the dynamics of their colonization and decolonization cycles could be elucidated and related to the variations in the groundwater level. Eight different colonization/decolonization cycles were determined, each one being characterized by a ‘typical’ common species. These included both passive and active movements in response to the changes in water level. Many taxa were shown to have behavioural strategies which altered according to the stages of their life cycles. Most aquatic invertebrates were adapted to move into the most stable conditions at a given time of the year. Certain terrestial species were also shown to tolerate short periods of immersion.
The effect of discharge and predation on habitat use by wild and hatchery brown trout (Salmo Trutta)
Authors: Greenberg Larry A. 
Published: February 2007

AbstractThe effects of trout stock, discharge and predation risk on habitat use by brown trout, Salmo trutta, were studied in four artificial streams. Trout stock had no effect on habitat use as both wild and hatchery fish used similar habitats. The presence of pike (Esox lucius) caused trout to decrease their use of pools, the habitat in which pike occurred, and increase their use of other habitats. Decreasing discharge reduced available area of the stream and resulted in fewer fish in the shallow margins. Both decreased flow and increased predation risk caused more overlap in habitat use, and thus increased the potential for intraspecific competition, predation and the use of poorer habitats. The results illustrate the danger of applying habitat use relationships obtained from one stream to all other streams where habitat availability and biotic interactions may differ.
Model study of the negara river basin to assess the regulating role of its wetlands
Authors: Klepper Olivier 
Published: February 2007

AbstractThe Sungai Negara basin covers about 4000 km2 of the Barito river floodplain in south‐east Borneo (Kalimantan). In view of plans to regulate the swamps in this area by impoldering or drainage a model study was initiated to describe the present state of the system and to assess potential impacts of these developments. In this paper a summary of the climatological, hydrological and topographical database is given, and model equations formulated. A comparison between calculated and observed river levels shows good agreement. The model is then used to estimate the increase in peak flows in the hypothetical absence of wetlands in the system. The results show that impoldering large areas of the wetlands would considerably increase the risk of flooding in the area. In another application, the model is used to calculate residence times in the lakes and swamps. This makes it possible to indicate the areas most sensitive for pollution. The results are also useful to assist in a soil mapping study, as only areas with very long residence times (only rain fed) coincide with peat areas.
Water quality changes and effects on fish populations in the hanjiang river, china, following hydroelectric dam construction
Authors: Liu J. K. , Yu Z. T. 
Published: February 2007

AbstractSince its completion in 1973 the Danjiangkou Dam has markedly changed downstream flows, water levels, temperatures, sediment loads and other water quality characteristics in downstream reaches of the Hanjiang River. There have been changes in the growth, spawning behaviour and overwintering condition of local fish populations, in the composition and abundance of food organisms and in the composition of the commercial fish catch. Despite the changed environment and the absence of a fish pass, fish populations are still able to grow and spawn under the new regime. Where conditions are like those of the Hanjiang River, dams may not necessarily have calamitous consequences for fishery production.
Quantification of daily peak hydropower effects on aquatic fauna and management to minimize environmental impacts
Authors: Moog Otto 
Published: February 2007

AbstractThe effects of intermittent power generation on the fish fauna and benthic invertebrates of several Austrian rivers have been investigated quantitatively. In contrast to the more or less local adverse effects of impoundments or stream channelization, artificial flow fluctuations generally disturb a long section of a given river. Within all the river sections investigated, a breakdown of the benthic invertebrate biomass of between 75 and 95% was observed within the first few kilometres of river length. A reduction of between 40 and 60% of biomass compared with undisturbed areas could be detected within the following 20–40 km. The reduction of the fish fauna is within the same order of magnitude and correlates well with the amplitude of the flow fluctuations. Several reasons for the breakdown are summarized and proposals for the minimization of these detrimental effects of artificial short‐term fluctuations are given.
Conceptual model for quantifying pre‐smolt production from flow‐dependent physical habitat and water temperature
Authors: Williamson S. C. , Bartholow J. M. , Stalnaker C. B. 
Published: February 2007

AbstractA conceptual model has been developed to test river regulation concepts by linking physical habitat and water temperature with salmonid population and production in cold water streams. Work is in progress to examine numerous questions as part of flow evaluation and habitat restoration programmes in the Trinity River of California and elsewhere. For instance, how much change in pre‐smolt chinook salmon (Oncorhynchus tshawytscha) production in the Trinity River would result from a different annual instream allocation (i.e. up or down from 271 × 106 m3 released in the late 1980s) and how much change in pre‐smolt production would result from a different release pattern (i.e. different from the 8.5 m3 s−1 year‐round release). The conceptual model is being used to: design, integrate and improve young‐of‐year population data collection efforts; test hypotheses that physical habitat significantly influences movement, growth and mortality of salmonid fishes; and analyse the relative severity of limiting factors during each life stage. The conceptual model, in conjunction with previously developed tools in the Instream Flow Incremental Methodology, should provide the means to more effectively manage a fishery resource below a regulated reservoir and to provide positive feedback to planning of annual reservoir operations.
Juvenile competitive bottleneck in the production of brown trout in hydroelectric reservoirs due to intraspecific habitat segregation
Authors: Hegge Ola , Hesthagen Trygve , Skurdal Jostein 
Published: February 2007

AbstractResource utilization and growth of brown trout were studied in four deep (mean depths 16.2–37.5 m) Norwegian hydroelectric reservoirs by benthic and pelagic gillnet sampling. In all the reservoirs supplementary stockings are carried out. The brown trout were spatially segregated according to size as the habitat use of small individuals (< 180–220 mm) was completely restricted to benthic habitats, whereas larger individuals mainly utilized the upper strata of pelagic waters. It is argued that the pelagic habitat is the more rewarding, and that small‐sized brown trout are forced into the less favourable benthic habitat through social interactions with larger specimens. This is supported by an increase in growth of brown trout from their third to fifth year of life, which seems to be related to the shift from benthic to pelagic behaviour. It is also argued that the conditions for small‐sized brown trout may be a bottleneck in the capacity to produce brown trout in hydroelectric reservoirs with limited benthic feeding conditions, despite ample access to food in pelagic habitats.When evaluating the possibility of increasing the yield of brown trout through supplementary stockings, it is therefore important to consider food and growth conditions for all age and size groups of brown trout. In reservoirs with poor benthic feeding conditions it may be necessary to stock with brown trout of sizes that are large enough to utilize pelagic habitat, to avoid the limiting benthic living stage.