The removal of dams is frequently promoted as a cost-effective tool for some forms of river rehabilitation, even though the scientific evidence supporting this approach is relatively rare. Our fifteen-month study assessed initial effects... more
The removal of dams is frequently promoted as a cost-effective tool for some forms of river rehabilitation, even though the scientific evidence supporting this approach is relatively rare. Our fifteen-month study assessed initial effects of removal of the Edwards Dam at three sites in the Kennebec River, Maine (USA) on zoobenthos, a critical component of a river's food web. Overall changes in both abundance and generic diversity were analysed in relation to feeding strategy. We also evaluated changes in trophic food webs by analysing stable isotope signatures of carbon and nitrogen for major functional feeding groups. The overall density of zoobenthos increased most dramatically (190 %) at the site closest to the former dam, but measures of taxonomic diversity showed variable responses. Neither generic richness nor evenness were significantly altered by removal of the dam. However, the composition of the community changed, with the addition of eight genera including caddisflies ...
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Ohio River zooplankton were collected monthly or quarterly for 1 yr from littoral and pelagic (main channel) areas in three navigation pools (constricted and floodplain) with four intrapool locations (lower pool and above, below, and... more
Ohio River zooplankton were collected monthly or quarterly for 1 yr from littoral and pelagic (main channel) areas in three navigation pools (constricted and floodplain) with four intrapool locations (lower pool and above, below, and within major tributaries). Total densities were minimal (1.64/L) when discharge and turbidities peaked (December-April) but were relatively high otherwise (21.63/L). Seasonal rises in rotifer density preceded increases in cladocerans and cspepods; rotifers were nearly twice as abundant as cladocesans and copepods. Diversity (species richness) was not correlated with temperature, velocity, or turbidity. Density was positively linked with temperature and negatively correlated with river velocity and turbidity. Diversities in littoral and pelagic areas were not different, but densities were higher nearshore (mostly copepods and cladocerans); rotifers were usually more common in the main channel. Neither proximity to low-head navigation dams nor channel mor...
Freshwater biodiversity is declining dramatically, and the current biodiversity crisis requires defining bold goals and mobilizing substantial resources to meet the challenges. While the reasons are varied, both research and conservation... more
Freshwater biodiversity is declining dramatically, and the current biodiversity crisis requires defining bold goals and mobilizing substantial resources to meet the challenges. While the reasons are varied, both research and conservation of freshwater biodiversity lag far behind efforts in the terrestrial and marine realms. We identify fifteen pressing global needs to support informed global freshwater biodiversity stewardship. The proposed agenda aims to advance freshwater biodiversity research globally as a critical step in improving coordinated action towards its sustainable management and conservation.
Research Interests: Business, Geography, Biology, Ecology, Freshwater Ecology, and 13 moreEnvironmental Planning, Biodiversity, Social Ecology, Medicine, Biodiversity Conservation, Crisis, Environmental Resource Management, Monitoring, Aquaculture and fisheries, Data Infrastructure, Research Priorities, Ecological Applications, and Freshwaters
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1994. Predicting the success of riverine populations of zebra mussels (Dreissena polymorpha) a se history of early colonization and microhabitat distribution in the Ohio River.
Research Interests: Environmental Engineering, Community Ecology, Experimental Ecology, Biology, Invasive species ecology, and 15 moreEcology, Invasive Species, Freshwater Ecology, Benthic Ecology, Biological invasions, Fish Ecology, Benthic macroinvertebrates, Biotic interactions, Food web, Large River Ecology, Freshwater Mussels, Freshwater Biology and Limnology, Cladocera, ENVIRONMENTAL SCIENCE AND MANAGEMENT, and Bosmina
Research Interests: Environmental Engineering, Stochastic Process, Environmental Science, Ecology, Fluvial Geomorphology, and 15 moreRiver, Protein Structure and Function, Product Model, Large River Ecology, Conceptual Model, Species Distribution, Spatial Scale, Floodplains, Ecosystem, Fluvial, Patch Dynamics, ENVIRONMENTAL SCIENCE AND MANAGEMENT, Metastable state, river continuum concept, and Ecosystem processes
Research Interests: Aquatic Ecology, Biology, Ecology, Benthic Ecology, Fish Ecology, and 15 moreBenthic macroinvertebrates, Food web ecology, Food webs, Aquatic Insects, Ecology of Submerged Macrophyte, Food web, Aquatic Macrophytes, Floodplain, Dissolved organic matter, Floodplains, Detritus, Bioassessment, Energy Source, Food Web structure, and ecosystem model
Research Interests: Aquatic Ecology, Macroecology, Water resources, Fisheries, Stream ecology, and 10 moreBiology, Natural Resource Management, Ecology, Global Environmental Change, Environmental Sustainability, River Ecology, Global Change Biology, Multidisciplinary, Ecology and Evolutionary Biology, and Drainage basin
Research Interests: Parasitology, Aquatic Ecology, Conservation, Freshwater Biology, Biology, and 12 moreInvasive species ecology, Ecology, Invasive Species, Freshwater Ecology, Plankton ecology, Biological Sciences, Environmental Sciences, Field Experiment, Zooplankton, Freshwater Mussels, Freshwater Biology and Limnology, and Predator Prey
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Research Interests: Geography, Physical Geography, Environmental Science, Geomorphology, Rehabilitation, and 15 moreEcosystem Services, Restoration Ecology, Biodiversity and Ecosystem Function, Stream ecology, Fluvial Geomorphology, River Ecology, Hydrology and Ecohydrology, Bioscience, Biological Sciences, Environmental Sciences, Hydrogeomorphology, Ecosystem, Ecosystem service, River Management, and Environmental benefit
... Snags are an important habitat for benthic macroinvertebrates (Claflin, 1968; McLachlan, 1970; Benke et al., 1984; Thorp et al., 1985; O'Connor, 1991) and provide forage and refuge for fish (Benke et al., 1979).... more
... Snags are an important habitat for benthic macroinvertebrates (Claflin, 1968; McLachlan, 1970; Benke et al., 1984; Thorp et al., 1985; O'Connor, 1991) and provide forage and refuge for fish (Benke et al., 1979). ... period of colonization (Thorp et al., 1985; O'Connor, 1991). ...
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Research Interests: Aquatic Ecology, Community Ecology, Experimental Ecology, Freshwater Biology, Biology, and 15 moreInvasive species ecology, Ecology, Invasive Species, Freshwater Ecology, Benthic Ecology, River Ecology, Fish Ecology, Food web ecology, Biological Sciences, Environmental Sciences, Relative Abundance, Cyprinus Carpio, Benthic Invertebrate Ecology, Dreissena, and Channel catfish
Research Interests: Environmental Engineering, Stream ecology, Biology, Ecology, River Ecology, and 15 morePlankton ecology, Habitat, Circadian Rhythm, Large River Ecology, Plankton, Animal migration, Littoral, Stream, Spatial Distribution, Diel Vertical Migration, Copepod, Female To Male, ENVIRONMENTAL SCIENCE AND MANAGEMENT, pelagic zone, and Bosmina
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We analyzed the gut contents of two species of Centrarchidae (the redbreast sunfish, Lepomis auritus and the pumpkinseed sunfish, L. gibbosus) and compared the diets of nesting and nonnesting individuals (position effect) at dawn and dusk... more
We analyzed the gut contents of two species of Centrarchidae (the redbreast sunfish, Lepomis auritus and the pumpkinseed sunfish, L. gibbosus) and compared the diets of nesting and nonnesting individuals (position effect) at dawn and dusk (time effect). Although redbreast and pumpkinseed sunfish differ somewhat in anatomy and ecology, they had similar diets and foraging patterns in Calder Lake. Nesting behavior caused a slight to major reduction in the quantity and diversity of prey eaten. Sunfish, which ate prey from both the benthos and water surface, consumed a higher percentage of benthic prey at dawn in comparison to the proportion taken at dusk. Position influenced the percentage of benthic prey eaten at both times. We explore the possibility that a male nonnesting genotype ("cuckold'' sunfish) might be retained in a population of mostly-nesting sunfish (parentals) because of the former's greater foraging success.
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... and tribu-taries. Rather than challenging the fundamental precepts of earlier theories, we suggest that the applicability of the RPM and previous hypotheses will vary withriver size and geomorphology. The revised RCC seems ...
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A 12-month study was conducted to measure the concentrations ofdissolved organic matter (DOC, TDN, TDP) in four sites within a119 km long reach of the Ohio River, near Louisville, KY. In thisstudy we test whether specific geomorphological... more
A 12-month study was conducted to measure the concentrations ofdissolved organic matter (DOC, TDN, TDP) in four sites within a119 km long reach of the Ohio River, near Louisville, KY. In thisstudy we test whether specific geomorphological and biologicalfactors influenced variations in dissolved organic matter.Concentrations of DOC in the river averaged ˜1200µmol/L, and varied by nearly two orders of magnitudeseasonally
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ABSTRACT
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Page 1. Page 2. 983 22 ST. LAWRENCE RIVER BASIN system can travel at least 3260 km from western Lake Superior to the Cabot Strait in the estuarine Gulf of St. Lawrence. Along this lenticloticestuarine pathway to the sea ...
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A field experiment was designed to test a frequent assumption in the literature that vertebrate predators (in this case, fish and turtles) are capable of regulating the seasonal abundance and diversity of benthic communities in the... more
A field experiment was designed to test a frequent assumption in the literature that vertebrate predators (in this case, fish and turtles) are capable of regulating the seasonal abundance and diversity of benthic communities in the littoral zone of lentic environments. Effects of thermal effluents from a nuclear reactor on predator-prey relationships were also examined. Benthic samples were removed after each of three, 3-month test periods from 36 predator exclusion cages (4m(2)) and 36 control plots located along a thermal gradient in Par Pond, an 1,100 ha freshwater reservoir in the southeastern United States.Results of our field experiments provide little evidence to suggest that either a single "keystone" species or vertebrate predators as a group were capable of regulating the abundance, diversity or productivity of chironomids in Par Pond. The relationship between predator treatment and community response (changes in density and species richness) was generally unaffected by either plot location or temperature fluctuations. When data from caged and control plots were pooled, however, both location and water temperature individually had significant impacts on the chironomid community. Alternative hypotheses are proposed to explain the lack of regulatory control of the benthic community by individual species or guilds of predators.
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I examined the relationship between temperature and agonistic behavior in the crayfish Cambarus latimanus LeConte a species which is reproductively active in winter. Crayfish were acclimated for 2 wks at 9.5, 14, 22 and 30°C in summer and... more
I examined the relationship between temperature and agonistic behavior in the crayfish Cambarus latimanus LeConte a species which is reproductively active in winter. Crayfish were acclimated for 2 wks at 9.5, 14, 22 and 30°C in summer and at 9.5 and 22°C in winter. Agonistic behavior of pairs of the same sex was recorded for 1 h following acclimation. The entire acclimation, testing, and temperature-readjustment procedure was repeated until all crayfish pairs had been tested at each acclimation temperature.Published information on lobsters and catfish indicate that agonistic behavior is directly related to temperature. In contrast, for C. latimanus in the present study, duration of total agonistic behavior, maximum duration of a single agonistic interaction, and average length of a agonistic encounter were all inversely related to acclimation temperature. I hypothesized that for ectothermic species whose agonistic behavior is closely associated with reproductive processes (including competition for mates) the level of agonism will vary either directly or inversely depending upon whether the reproductive period is cued by increasing or decreasing seasonal temperatures, respectively.
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ABSTRACT