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Unidentified Photographer - One of the best experts on this subject based on the ideXlab platform.
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Leggett headgate, Denver diversion, Gravel Pits, Barker Dam. 3
Colorado State University. Libraries, 2021Co-Authors: Unidentified PhotographerAbstract:From group of images of water structures; image 1 caption reads, "Denver Diversion," image 3, "Gravel? Pit above Barker Dam," image 4, "Barker Dam," image 8 "Barker," image 26, "Leggett headgates, 12 July '56," image 27, "Leggett headgates So. Boulder Cr., 12 July '56," image 28, "Diversion for Denver w.s. above."3 of 28 35 mm slides.Caption: Gravel? Pit above Barker Dam
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Leggett headgate, Denver diversion, Gravel Pits, Barker Dam. 11
Colorado State University. Libraries, 2021Co-Authors: Unidentified PhotographerAbstract:From group of images of water structures; image 1 caption reads, "Denver Diversion," image 3, "Gravel? Pit above Barker Dam," image 4, "Barker Dam," image 8 "Barker," image 26, "Leggett headgates, 12 July '56," image 27, "Leggett headgates So. Boulder Cr., 12 July '56," image 28, "Diversion for Denver w.s. above."11 of 28 35 mm slides
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Leggett headgate, Denver diversion, Gravel Pits, Barker Dam. 28
Colorado State University. Libraries, 2021Co-Authors: Unidentified PhotographerAbstract:From group of images of water structures; image 1 caption reads, "Denver Diversion," image 3, "Gravel? Pit above Barker Dam," image 4, "Barker Dam," image 8 "Barker," image 26, "Leggett headgates, 12 July '56," image 27, "Leggett headgates So. Boulder Cr., 12 July '56," image 28, "Diversion for Denver w.s. above."28 of 28 35 mm slides.Caption: Diversion for Denver w.s. above
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Leggett headgate, Denver diversion, Gravel Pits, Barker Dam. 26
Colorado State University. Libraries, 2021Co-Authors: Unidentified PhotographerAbstract:From group of images of water structures; image 1 caption reads, "Denver Diversion," image 3, "Gravel? Pit above Barker Dam," image 4, "Barker Dam," image 8 "Barker," image 26, "Leggett headgates, 12 July '56," image 27, "Leggett headgates So. Boulder Cr., 12 July '56," image 28, "Diversion for Denver w.s. above."26 of 28 35 mm slides.Caption: Leggett headgates, 12 July '56
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Leggett headgate, Denver diversion, Gravel Pits, Barker Dam. 25
Colorado State University. Libraries, 2021Co-Authors: Unidentified PhotographerAbstract:From group of images of water structures; image 1 caption reads, "Denver Diversion," image 3, "Gravel? Pit above Barker Dam," image 4, "Barker Dam," image 8 "Barker," image 26, "Leggett headgates, 12 July '56," image 27, "Leggett headgates So. Boulder Cr., 12 July '56," image 28, "Diversion for Denver w.s. above."25 of 28 35 mm slides
Jost Borcherding - One of the best experts on this subject based on the ideXlab platform.
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population ecology vertical migration and feeding of the ponto caspian invader hemimysis anomala in a Gravel Pit lake connected to the river rhine
Freshwater Biology, 2006Co-Authors: Jost Borcherding, Simone Murawski, Hartmut ArndtAbstract:Summary 1. The Ponto-Caspian invader, Hemimysis anomala, was recently found in large numbers in a Gravel-Pit lake connected to the Lower Rhine. Mysids were sampled with Perspex traps between September 2002 and April 2003 to study the population dynamics, vertical migration and feeding. 2. The abundance (as catch per unit effort, CPUE) of H. anomala declined from 270 individuals (ind.) trap−1 (4 h)−1 in December to below 4 ind. trap−1 (4 h)−1 in April. Average lengths ranged from 4.9 mm in autumn to 9.9 mm in March. The length–weight relationship of virgin females changed throughout the sampling period, from a size-corrected wet weight of 5.1 mg in September to 16.6 mg in April for a female of 7.8 mm. 3. Successive monthly samples taken over 24 h revealed that H. anomala preferred the surface at twilight and night. During dawn the mysids migrated to the middle and bottom layers and were hardly found during day. Diel vertical migration clearly depends on the proximate factor light. 4. Stomach analyses revealed that larger H. anomala preferred zooplankton, whereas small individuals fed more on phytoplankton. The seasonal comparison showed an increasing percentage of zooplankton with increasing length. The proportion of zooplankton in the stomachs of large H. anomala individuals was highest during night and lowest during day. 5. The results suggest that H. anomala may become an important link between primary/secondary production and higher trophic levels in the food web of its new environments at the Lower Rhine.
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0+ perch predation on 0+ bream: a case study in a eutrophic Gravel Pit lake
Freshwater Biology, 2002Co-Authors: Peter Beeck, Sandra Tauber, Stephanie Kiel, Jost BorcherdingAbstract:1. We studied the population dynamics of 0+ fish in a eutrophic Gravel Pit lake in which predation of 0+ Eurasian perch on other 0+ fish was suspected to influence perch growth and the structure of the fish community, with effects on the lake food web. 2. The adult fish community was dominated by piscivorous species, especially perch, and the 0+ fish community was dominated by perch and bream. Bream grew to a total length of 80 mm between May and the end of August, gradually decreased in numbers during the summer, and completely disappeared in autumn. Stomach analysis revealed that 0+ perch ≥28 mm fed on 0+ bream. 3. The initially unimodal cohort of 0+ perch gradually broadened and became bimodal by the end of July. Fish of the larger, piscivorous cohort grew faster (1.4 mm day -1 ) than the smaller, zooplankton-consuming fish (0.6 mm day -1 ). Although individuals of both cohorts later consumed zooplankton and grew at similar rates (0.5 mm day -1 ), only perch of the large cohort (mean TL 125 mm) were found by mid-October. Intraspecific competition for food or cannibalism of older perch may have contributed to the disappearance of the smaller perch. 4. Early piscivory of the fast-growing 0+ perch apparently resulted in the disappearance of 0+ bream by the end of the growing season and precocious maturation of male perch. In contrast to findings in other studies, these large 0+ perch thus avoided the juvenile bottleneck by switching to piscivory early during their ontogenetic development. 5. The observations of this study suggest that early piscivory of 0+ perch can have a long-lasting impact on fish communities in eutrophic lakes, particularly if prey fish are abundant and the structural complexity of the lake is low. Furthermore, early piscivory of 0+ perch may help prevent the expected increase in 0+ cyprinids following reduction of adult cyprinids, which is considered important to ensure the long-term success of biomanipulation experiments.
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the seasonal succession of macroinvertebrates in particular the zebra mussel dreissena polymorpha in the river rhine and two neighbouring Gravel Pit lakes monitored using artificial substrates
International Review of Hydrobiology, 2002Co-Authors: Jost Borcherding, Wolfgang SturmAbstract:Artificial substrate samplers were used to study the seasonal succession of macroinvertebrates in the River Rhine and two neighbouring Gravel-Pit lakes. In two experimental series nearly all epilithic macroinvertebrates normally found at each site settled on the artificial substrates. The analysis of the results showed that the use of artificial substrates is an adequate tool for studying (1) different aspects of the life cycles of species which frequently settle on the plates (e.g. Bryozoa, Corophium curvispinum), (2) seasonal successions of macroinvertebrate communities, and (3) aspects of competition and support within a macroinvertebrate community. The total biomass of macroinvertebrates, in particular the growth of juvenile Dreissena polymorpha, accurately reflected the productivity of the different waters, with highest values for the lake connected to the river, somewhat lower ones for the Rhine, and very low production values for the isolated lake. In other words, a few easily-made measurements of the productivity of primary consumers may be very useful for biological monitoring studies of the floodplains of rivers.
Marco Antonellini - One of the best experts on this subject based on the ideXlab platform.
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the effect of artificial recharge on hydrochemistry a comparison of two fluvial Gravel Pit lakes with different post excavation uses in the netherlands
Water, 2016Co-Authors: Pauline Nella Mollema, Marco Antonellini, Alwin Hubeek, Peter Van DiepenbeekAbstract:Gravel Pit lakes form when Gravel deposits are excavated below the water table. We studied two fluvial Gravel Pit lakes called De Lange Vlieter (DLV Lake) and the Boschmolen Plas (BP Lake), in the Meuse River valley (The Netherlands). Water from the Meuse River is pumped only into the DLV Lake that is used for drinking water production. The mean values, the linear trends and seasonal patterns of time series data (2003–2014), of temperature, pH, nitrate, phosphate and sulphate were compared using one-way tests of variance and tests of differences. The effects of river water infiltration on DLV Lake are (1) a change in lake water temperature; (2) an increase in nitrate concentration (3) an increase in phosphate concentration and (4) a decrease in sulphate concentration. The effects of the air blowers in DLV Lake are (1) mixing of lake water; (2) decreasing pH in spring and summer (3) water oxygenation. Linear regression analysis shows an initially increasing nitrate concentration in DLV Lake that can be explained by the input of nitrate rich Meuse river water. Instead decreasing nitrate and phosphate concentrations in BP Lake and Meuse River reflect a diminished use of fertilizers. The Gravel Pit lake water temperature does not reflect climatic changes but the use of DLV Lake for artificial recharge has an impact on the seasonal and long-term trends in hydrochemistry. This poses a challenge to lake managers to find the right balance between reduction of eutrophication and accumulation of nutrients and sulphate.
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water and bio chemical cycling in Gravel Pit lakes a review and outlook
Earth-Science Reviews, 2016Co-Authors: Pauline Nella Mollema, Marco AntonelliniAbstract:Abstract The world produces 1.7 × 10 8 metric tons of Gravel and sand per year (USGS, 2015) creating many Gravel Pit lakes that change the morphology and drainage pattern of catchments. Gravel Pit lakes abruptly intersect the geologic layering creating an environment where surface and groundwater will interact and where elaborate food webs can develop. Here we preview previous work on Gravel Pit lakes and compiled a comprehensive hydrochemical database to compare the chemistry of Gravel Pit lake water with other types of surface and groundwater. Water budget calculations confirm that Gravel Pit lakes cause freshwater loss in temperate and Mediterranean climates where surface water evaporation is larger than the actual evapotranspiration of vegetated land that was replaced by the Gravel Pit lakes. Groundwater fed Gravel Pit lakes where evaporated water is replaced by groundwater are especially sensitive to climate change. The Gravel Pit lakes included in this review have a relatively low acidity and high alkalinity most likely caused by weathering and leaching of carbonates in the catchment. The inflow of groundwater is a key process in Gravel Pit lakes with important consequences. The creation or presence of the Gravel Pit lakes may induce fluctuation of the up-stream water table which enhances groundwater flow and redox reactions in the soil. Groundwater rich in dissolved elements typically meets more alkaline water in Gravel Pit lakes enhancing the preciPitation of metal oxides, calcite and other composite minerals including phosphorus (P), calcium (Ca) and carbon (C). Gravel Pit lakes provide many different ecological habitats increasing the biodiversity in typically an agricultural or urban setting. Plant and animal species observed in Gravel Pit lakes consists of phytoplankton, zooplankton, micro plankton, macrophytes, fish and birds similar to natural lakes but the fact that Gravel Pit lakes may be only groundwater fed, or instead in open contact with rivers causes large variations between the ecosystem of different lakes. Plants and animal species take part in the chemical cycling of Gravel Pit lakes by, among others, uptake of atmospheric carbon dioxide (CO 2 ) and nitrogen (N 2 ), of dissolved compounds including bicarbonate (HCO 3 ), iron (Fe) and manganese (Mn); of elements including phosphate (P) and Fe from lake sediments, and carbon mineralization and burial. Gravel Pit lakes may contribute to denitrification of groundwater as N is consumed by plankton, but they may also enhance the mobilization of soil-bound compounds like potentially toxic (trace) metals released from aquifer sediments. The creation of Gravel Pit lakes provides more available sites for carbon burial but once deposited on the lake bottom, metals and other elements may be released again due to redox cycling, influenced by climatic or land use change. Gravel Pit lakes are water bodies of recent formation and so far only a few different settings have been studied in detail compared to other types of natural- and man-made lakes. From this review it is evident that Gravel Pit lakes are hydrochemically most similar to so called ‘marl lakes’ or ‘nutrient rich’ lakes. Key areas for further research include the study of Gravel Pit lakes in other settings to better separate the similarities and differences between natural and Gravel Pit lakes. Also the feedback mechanisms between change in land use and climate, ground- and lake water chemistry ecological functioning and use of the Gravel Pit lakes need to be addressed.
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the influence of flow through saline Gravel Pit lakes on the hydrologic budget and hydrochemistry of a mediterranean drainage basin
Limnology and Oceanography, 2015Co-Authors: Pauline N Mollema, Marco Antonellini, Enrico Dinelli, Nicolas Greggio, Pieter Jan StuyfzandAbstract:Flow-through brackish Gravel Pit lakes near the Adriatic Coast of Emilia Romagna (Italy) in the Mediterranean have a large influence on the hydrologic budget of the watershed. Strong evaporation in combination with intense drainage of the low lying basins enhances groundwater inflow into the lake. PreciPitation falling on the lakes is mixed with brackish/saline lake water causing the loss of freshwater. The Gravel Pit lakes are characterized by a high salinity (TDS = 4.6–12.3 g L−1) and high pH (8.5). Stable isotope data show that Gravel Pit lake water is fed by groundwater which is a mix of Apennine River water and (Holocene) Adriatic Seawater, subsequently enriched by evaporation. The slope of the local evaporation line is 5.4. Conservative tracer and water budget modeling shows that the final Cl concentration depends strongly on the ratio of evaporation to total inflow. Increasing drainage to compensate for sea level rise, subsidence or intense preciPitation would enhance ground water flow into the lake and decrease Cl concentration while increasing evaporation would increase Cl concentration. Groundwater rich in dissolved trace elements flows into the Gravel Pit lakes that contains water with a higher pH and dissolved oxygen. Pit lake water remains enriched in some elements (e.g., Ba, Mo, Sb) and depleted in others (e.g., Fe, Ca, Zn, SO4) with respect to groundwater composition. The Gravel Pit lakes show limited eutrophication but the water quality should be monitored for trace elements (e.g., As) if they are to be used for recreational purposes.
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metal accumulation in an artificially recharged Gravel Pit lake used for drinking water supply
Journal of Geochemical Exploration, 2015Co-Authors: Pauline Nella Mollema, P J Stuyfzand, M H A Juhaszholterman, P M J A Van Diepenbeek, Marco AntonelliniAbstract:Abstract Gravel Pit lakes offer a variety of uses after excavation has ceased. One of those uses is the storage, infiltration, aquifer passage, and production of drinking water. We have investigated such a Gravel Pit lake in The Netherlands that is a state of the art drinking water production facility. The Gravel Pit lake is a flow-through lake, fed naturally by groundwater (~ 17%) and rainwater (~ 6%), and artificially with Meuse River water (~ 77%). The average concentrations of Cd, Cr, Cu, Ni, Pb and Zn in the lake's bottom sediments have increased over a 10 year period. Acidifying redox reactions caused by lowering of the water table and farmland fertilization upstream from the lake explain the mobilization of metals in the soil and subsequent transport with groundwater towards the lake. Dissolved metals (Al, Cd, Cr, Cu, Fe Mn, Ni and Zn) and PO 4 3 − flow with the groundwater towards the lake, where they interact with oxygen-rich and alkaline water to (co)preciPitate as Fe, Mn and Al oxides. The chemistry of the Gravel Pit lake water is determined by a complex interplay between the input of NO 3 − and PO 4 3 − , soil composition up stream, biochemical processes in the lake that supply organic material, mixing processes (artificial and natural) that determine the amount of stratification and oxygen, and redox cycling processes in the bottom sediments that influence the concentration of metals and P in the lake water. Gravel Pit lakes are young compared to natural lakes and the long term influence of these lakes is still largely unknown. This study confirms that they can form a sink for metals and thus influence the metal budget of a watershed. Compared to other artificial recharge methods, infiltration in a Gravel Pit lake along a river has certain advantages in that the lake already exists, the transport distance for the water to be infiltrated is short, the pretreatment of the infiltrated water is simple, and the long residence time of the water in the lake and the lake bank filtration attenuates quality variations of the infiltrated river water. For drinking water production or other usage of Gravel Pit lakes, an integrated monitoring and management of land use, ground- and surface water as well as lake bottom sediments are needed.
Pauline Nella Mollema - One of the best experts on this subject based on the ideXlab platform.
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the effect of artificial recharge on hydrochemistry a comparison of two fluvial Gravel Pit lakes with different post excavation uses in the netherlands
Water, 2016Co-Authors: Pauline Nella Mollema, Marco Antonellini, Alwin Hubeek, Peter Van DiepenbeekAbstract:Gravel Pit lakes form when Gravel deposits are excavated below the water table. We studied two fluvial Gravel Pit lakes called De Lange Vlieter (DLV Lake) and the Boschmolen Plas (BP Lake), in the Meuse River valley (The Netherlands). Water from the Meuse River is pumped only into the DLV Lake that is used for drinking water production. The mean values, the linear trends and seasonal patterns of time series data (2003–2014), of temperature, pH, nitrate, phosphate and sulphate were compared using one-way tests of variance and tests of differences. The effects of river water infiltration on DLV Lake are (1) a change in lake water temperature; (2) an increase in nitrate concentration (3) an increase in phosphate concentration and (4) a decrease in sulphate concentration. The effects of the air blowers in DLV Lake are (1) mixing of lake water; (2) decreasing pH in spring and summer (3) water oxygenation. Linear regression analysis shows an initially increasing nitrate concentration in DLV Lake that can be explained by the input of nitrate rich Meuse river water. Instead decreasing nitrate and phosphate concentrations in BP Lake and Meuse River reflect a diminished use of fertilizers. The Gravel Pit lake water temperature does not reflect climatic changes but the use of DLV Lake for artificial recharge has an impact on the seasonal and long-term trends in hydrochemistry. This poses a challenge to lake managers to find the right balance between reduction of eutrophication and accumulation of nutrients and sulphate.
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water and bio chemical cycling in Gravel Pit lakes a review and outlook
Earth-Science Reviews, 2016Co-Authors: Pauline Nella Mollema, Marco AntonelliniAbstract:Abstract The world produces 1.7 × 10 8 metric tons of Gravel and sand per year (USGS, 2015) creating many Gravel Pit lakes that change the morphology and drainage pattern of catchments. Gravel Pit lakes abruptly intersect the geologic layering creating an environment where surface and groundwater will interact and where elaborate food webs can develop. Here we preview previous work on Gravel Pit lakes and compiled a comprehensive hydrochemical database to compare the chemistry of Gravel Pit lake water with other types of surface and groundwater. Water budget calculations confirm that Gravel Pit lakes cause freshwater loss in temperate and Mediterranean climates where surface water evaporation is larger than the actual evapotranspiration of vegetated land that was replaced by the Gravel Pit lakes. Groundwater fed Gravel Pit lakes where evaporated water is replaced by groundwater are especially sensitive to climate change. The Gravel Pit lakes included in this review have a relatively low acidity and high alkalinity most likely caused by weathering and leaching of carbonates in the catchment. The inflow of groundwater is a key process in Gravel Pit lakes with important consequences. The creation or presence of the Gravel Pit lakes may induce fluctuation of the up-stream water table which enhances groundwater flow and redox reactions in the soil. Groundwater rich in dissolved elements typically meets more alkaline water in Gravel Pit lakes enhancing the preciPitation of metal oxides, calcite and other composite minerals including phosphorus (P), calcium (Ca) and carbon (C). Gravel Pit lakes provide many different ecological habitats increasing the biodiversity in typically an agricultural or urban setting. Plant and animal species observed in Gravel Pit lakes consists of phytoplankton, zooplankton, micro plankton, macrophytes, fish and birds similar to natural lakes but the fact that Gravel Pit lakes may be only groundwater fed, or instead in open contact with rivers causes large variations between the ecosystem of different lakes. Plants and animal species take part in the chemical cycling of Gravel Pit lakes by, among others, uptake of atmospheric carbon dioxide (CO 2 ) and nitrogen (N 2 ), of dissolved compounds including bicarbonate (HCO 3 ), iron (Fe) and manganese (Mn); of elements including phosphate (P) and Fe from lake sediments, and carbon mineralization and burial. Gravel Pit lakes may contribute to denitrification of groundwater as N is consumed by plankton, but they may also enhance the mobilization of soil-bound compounds like potentially toxic (trace) metals released from aquifer sediments. The creation of Gravel Pit lakes provides more available sites for carbon burial but once deposited on the lake bottom, metals and other elements may be released again due to redox cycling, influenced by climatic or land use change. Gravel Pit lakes are water bodies of recent formation and so far only a few different settings have been studied in detail compared to other types of natural- and man-made lakes. From this review it is evident that Gravel Pit lakes are hydrochemically most similar to so called ‘marl lakes’ or ‘nutrient rich’ lakes. Key areas for further research include the study of Gravel Pit lakes in other settings to better separate the similarities and differences between natural and Gravel Pit lakes. Also the feedback mechanisms between change in land use and climate, ground- and lake water chemistry ecological functioning and use of the Gravel Pit lakes need to be addressed.
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metal accumulation in an artificially recharged Gravel Pit lake used for drinking water supply
Journal of Geochemical Exploration, 2015Co-Authors: Pauline Nella Mollema, P J Stuyfzand, M H A Juhaszholterman, P M J A Van Diepenbeek, Marco AntonelliniAbstract:Abstract Gravel Pit lakes offer a variety of uses after excavation has ceased. One of those uses is the storage, infiltration, aquifer passage, and production of drinking water. We have investigated such a Gravel Pit lake in The Netherlands that is a state of the art drinking water production facility. The Gravel Pit lake is a flow-through lake, fed naturally by groundwater (~ 17%) and rainwater (~ 6%), and artificially with Meuse River water (~ 77%). The average concentrations of Cd, Cr, Cu, Ni, Pb and Zn in the lake's bottom sediments have increased over a 10 year period. Acidifying redox reactions caused by lowering of the water table and farmland fertilization upstream from the lake explain the mobilization of metals in the soil and subsequent transport with groundwater towards the lake. Dissolved metals (Al, Cd, Cr, Cu, Fe Mn, Ni and Zn) and PO 4 3 − flow with the groundwater towards the lake, where they interact with oxygen-rich and alkaline water to (co)preciPitate as Fe, Mn and Al oxides. The chemistry of the Gravel Pit lake water is determined by a complex interplay between the input of NO 3 − and PO 4 3 − , soil composition up stream, biochemical processes in the lake that supply organic material, mixing processes (artificial and natural) that determine the amount of stratification and oxygen, and redox cycling processes in the bottom sediments that influence the concentration of metals and P in the lake water. Gravel Pit lakes are young compared to natural lakes and the long term influence of these lakes is still largely unknown. This study confirms that they can form a sink for metals and thus influence the metal budget of a watershed. Compared to other artificial recharge methods, infiltration in a Gravel Pit lake along a river has certain advantages in that the lake already exists, the transport distance for the water to be infiltrated is short, the pretreatment of the infiltrated water is simple, and the long residence time of the water in the lake and the lake bank filtration attenuates quality variations of the infiltrated river water. For drinking water production or other usage of Gravel Pit lakes, an integrated monitoring and management of land use, ground- and surface water as well as lake bottom sediments are needed.
Robert Arlinghaus - One of the best experts on this subject based on the ideXlab platform.
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environmental determinants of perch perca fluviatilis growth in Gravel Pit lakes and the relative performance of simple versus complex ecological predictors
Ecology of Freshwater Fish, 2020Co-Authors: Leander Hohne, Sven Matern, Robert Nikolaus, Robert Arlinghaus, Miquel Palmer, Christopher T Monk, Ashley TrudeauAbstract:Growth of fish is an important contributor to individual fitness as well as fish production. Explaining and predicting growth variation across populations is thus important from fundamental and applied perspectives, which requires knowledge about the ecological factors involved in shaping growth. To that end, we estimated environment‐dependent von Bertalanffy growth models for 13 Gravel Pit lake populations of Eurasian perch (Perca fluviatilis) from north‐western Germany. To identify the main drivers of perch growth, we evaluated the performance of 16 different biotic or abiotic lake variables in explaining growth variation among lakes. In addition, we compared growth predictions from the best‐performing model incorporating “complex” variables that require intensive sampling effort, with a model using only “simple”, easily measurable lake variables (e.g. shoreline development factor). The derivation of a simple model aimed at future applications in typically data‐poor inland fisheries, predicting expected growth potential from easily measurable lake variables. A model combining metabolic biomass of predators, maximum depth and shoreline development factor performed best in predicting perch growth variation across Gravel Pits. All three parameters in this model were positively related to perch growth. The best‐performing simple model consisted only of the shoreline development factor. Length‐at‐age predictions from both models were largely identical, highlighting the utility of shoreline development factor in approximating growth potential of perch in Gravel Pits similar to our study lakes. Our results can be used to inform fisheries management and restoration efforts at existing or newly excavated Gravel Pit lakes.
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effect of recreational fisheries management on fish biodiversity in Gravel Pit lakes with contrasts to unmanaged lakes
Journal of Fish Biology, 2019Co-Authors: Sven Matern, Matthias Emmrich, Thomas Klefoth, Christian Wolter, Robert Nikolaus, Nicola Wegener, Robert ArlinghausAbstract:Gravel Pit lakes are novel ecosystems that can be colonized by fish through natural or anthropogenic pathways. In central Europe, many of them are managed by recreational anglers and thus experience regular fish stocking. However, also unmanaged Gravel Pits may be affected by stocking, either through illegal fish introductions or, occasionally, by immigration from connected water bodies. We sampled 23 small (< 20 ha) Gravel Pit lakes (16 managed and 7 unmanaged) in north-western Germany using littoral electrofishing and multimesh gillnets. Our objective was to compare the fish biodiversity in Gravel Pit lakes in the presence or absence of recreational fisheries. Given the size of the sampled lakes, we expected species poor communities and elevated fish diversity in the managed systems due to regular stocking of game fish species. Our study lakes were primarily mesotrophic and did not differ in key abiotic and biotic environmental characteristics. Lakes of both management types hosted similar fish abundances and biomasses, but were substantially different in terms of fish community structure and species richness. Fish were present in all lakes, with a minimum of three species. Higher α-diversity and lower β-diversity was discovered in managed Gravel Pit lakes compared to unmanaged lakes. Consequently, recreational-fisheries management fostered homogenization of fish communities, by stocking a similar set of fish species desired by anglers such as piscivorous fish and large bodied cyprinids. However, unmanaged Gravel Pit lakes were also affected by human-mediated colonization, presumably by illegal fish releases. Hardly any non-native species were detected, suggesting that recreational-fisheries management did not foster the spread of exotic species in our study region.
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impact of recreational fisheries management on fish biodiversity in Gravel Pit lakes with contrasts to unmanaged lakes
bioRxiv, 2018Co-Authors: Sven Matern, Matthias Emmrich, Thomas Klefoth, Christian Wolter, Nicola Wegener, Robert ArlinghausAbstract:Gravel Pit lakes constitute novel ecosystems that can be colonized by fishes through natural or anthropogenic pathways. Many of these man-made lakes are used by recreational anglers and experience regular fish stocking. Recreationally unmanaged Gravel Pits may also be affected by fish introductions, e.g., through illegal fish releases, thereby contributing to the formation of site-specific communities. Our objective was to compare the fish biodiversity in Gravel Pit lakes with and without the recent influence of recreational fisheries management. We sampled 23 small (< 20 ha) Gravel Pit lakes (16 managed and 7 unmanaged) in north-western Germany and compared fish community and diversity metrics obtained using littoral electrofishing and multimesh gillnet catch per unit effort data. Given the size of the lakes we sampled we expected species poor communities and elevated fish diversity in the managed systems due to stocking. The two lake types were primarily mesotrophic and did not differ in key abiotic and biotic environmental characteristics. Both lakes types hosted similar fish abundance and biomass, but were substantially different in terms of the fish community structure and species richness. Fish were present in all lakes with at least three species. We discovered a higher -diversity and a lower {beta}-diversity in managed Gravel Pit lakes compared to unmanaged lakes. Thus, recreational fisheries management appeared to foster homogenization of fish communities, likely because fisheries managers stock these lakes with desired fish species (e.g., piscivorous fishes and large bodied cyprinids). However, we also detected anthropogenic pathways in the colonization of unmanaged Gravel Pit lakes, presumably from illegal releases by private people. Importantly, hardly any non-native species were detected in the Gravel Pits we studied, suggesting that recreational fisheries management not necessarily promotes the spread of exotic species.
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no differences between littoral fish community structure of small natural and Gravel Pit lakes in the northern german lowlands
Limnologica, 2014Co-Authors: Matthias Emmrich, Robert Arlinghaus, Svenja Schalicke, Daniel Huhn, Christian LewinAbstract:Habitat loss has been identified as a major contributor to declining freshwater biodiversity, resulting in a high threat level among European fishes. Non-natural ecosystems such as Pit lakes may compensate habitat loss by providing new habitat for aquatic organisms. We compared the structure of the littoral fish communities of 18 natural and 19 Gravel Pit lakes located in the northern German lowlands to evaluate whether artificial lakes managed by angling clubs host similar communities as typically observed in natural lakes. The fish community structure was analyzed between the lake types and along gradients of lake morphometry, productivity and littoral complexity. Although the Gravel Pit lakes differed in morphology (characterized by steeper littoral slopes and less structured littoral habitat), differences in fish community structure between the natural and Gravel Pit lakes were weak and mainly related to differences in the abundance of the dominant species perch, roach and rudd. Both lake types had similar species richness, community diversity and hosted several small-bodied and endangered species. To conclude, fish communities characteristic of small natural lakes may serve as reference for the development of Gravel Pit lakes. Moreover, our study reveals that recreational-fisheries management of Gravel Pit lakes does not result in artificial communities that deviate strongly from the communities present in natural lakes. Therefore, nature conservation and fisheries management goals can be reconciled in relation to fish in small artificial lakes managed by angling clubs.
