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Abdominally implanted transmitters with percutaneous antennas affect the dive performance of Common Eiders
Implanted transmitters have become an important tool for studying the ecology of sea ducks, but their effects remain largely undocumented. To address this, we assessed how abdominally implanted transmitters with percutaneous antennas affect the vertical dive speeds, stroke frequencies, bottom time, and dive duration of captive Common Eiders (...
Powell, Abby N.; Latty, Christopher J.; Hollmén, Tuula E.; Petersen, Margaret R.; Andrews, Russel D.Comparative morphology among northern populations of breeding Cooper's Hawks
Few studies at a broad geographical scale have characterized intraspecific variation in morphology of woodland hawks in the genus Accipiter. From 1999 to 2007 we investigated morphological variation in large samples of live Cooper's Hawks (A. cooperii) nesting in four study areas: coniferous woodland around Victoria, British Columbia, Canada...
Rosenfield, Robert N.; Rosenfield, Laura J.; Bielefeldt, John; Murphy, Robert K.; Stewart, Andrew C.; Stout, William E.; Driscoll, Timothy G.; Bozek, Michael A.Unintended effects of electrofishing on nongame fishes
Most studies of injury associated with electrofishing have focused on game fishes, but few have given attention to cohabiting small nongame species. Under controlled laboratory conditions, we subjected small nongame cyprinids, ictalurids, and percids to a wide range of voltages and waveforms to examine potential harmful effects. Fish were treated...
Miranda, Leandro E.; Kidwell, R. H.Effects of riparian timber harvesting on instream habitat and fish assemblages in northern Minnesota streams
Relatively few evaluations of aquatic macroinvertebrate and fish communities have been published in peer-reviewed literature detailing the effect of varying residual basal area (RBA) after timber harvesting in riparian buffers. Our analysis investigated the effects of partial harvesting within riparian buffers on aquatic macroinvertebrate and fish...
Chizinski, Christopher J.; Vondracek, Bruce C.; Blinn, Charles R.; Newman, Raymond M.; Atuke, Dickson M.; Fredricks, Keith; Hemstad, Nathaniel A.; Merten, Eric; Schlesser, NicholasScale-dependent mechanisms of habitat selection for a migratory passerine: an experimental approach
Habitat selection theory predicts that individuals choose breeding habitats that maximize fitness returns on the basis of indirect environmental cues at multiple spatial scales. We performed a 3-year field experiment to evaluate five alternative hypotheses regarding whether individuals choose breeding territories in heterogeneous landscapes on the...
Donovan, Therese M.; Cornell, Kerri L.Effects of cadmium, estradiol-17beta and their interaction on gonadal condition and metamorphosis of male and female African clawed frog, Xenopus laevis
To assess interaction effects between cadmium (Cd, a putative xenoestrogen) and estradiol-17beta (E(2)) on sex differentiation and metamorphosis, Xenopus laevis were exposed to solvent-control (0.005% ethanol), Cd (10microgL(-1)), E(2) (1microgL(-1)), or Cd and E(2) (Cd+E(2)) in FETAX medium from fertilization to 75d postfertilization. Each...
Sharma, Bibek; Patino, ReynaldoFish habitat degradation in U.S. reservoirs
As the median age of the thousands of large reservoirs (> 200 ha) in the United States tops 50, many are showing various signs of fish habitat degradation. Our goal was to identify major factors degrading fish habitat in reservoirs across the country, and to explore regional degradation patterns. An online survey including 14 metrics was scored...
Miranda, Leandro E.; Spickard, M.; Dunn, T.; Webb, K.M.; Aycock, J.N.; Hunt, K.Habitat selection and abundance of young-of-year smallmouth bass in north temperate lakes
Habitat use during early life history plays an important role in the ecology of smallmouth bass Micropterus dolomieu in north temperate lakes. The highest levels of mortality occur during the first year of life, and the habitat selected probably affects mortality. We used resource selection functions and abundance data from two northern...
Brown, Peter James; Bozek, Michael A.Assessing effects of water abstraction on fish assemblages in Mediterranean streams
1. Water abstraction strongly affects streams in arid and semiarid ecosystems, particularly where there is a Mediterranean climate. Excessive abstraction reduces the availability of water for human uses downstream and impairs the capacity of streams to support native biota. 2. We investigated the flow regime and related variables in six river...
Benejam, Lluis; Angermeier, Paul L.; Munne, Antoni; García-Berthou, EmiliEvidence of panmixia between sympatric life history forms of coastal cutthroat trout in two lower Columbia River tributaries
Coastal cutthroat trout Oncorhynchus clarkii clarkii exhibit resident and migratory life history strategies that often occur sympatrically, but the relationship between these forms within a population is poorly characterized. Through use of passive integrated transponder technology, migratory and resident coastal cutthroat trout were...
Johnson, Jeffrey R.; Baumsteiger, Jason; Zydlewski, Joseph D.; Hudson, J. Michael; Ardren, William R.Ecoregion and land-use influence invertebrate and detritus transport from headwater streams
Summary 1. Habitats are often connected by fluxes of energy and nutrients across their boundaries. For example, headwater streams are linked to surrounding riparian vegetation through invertebrate and leaf litter inputs, and there is evidence that consumers in downstream habitats are subsidised by resources flowing from headwater systems. However...
Binckley, Christopher A.; Wipfli, Mark S.; Medhurst, R. Bruce; Polivka, Karl; Hessburg, Paul F.; Salter, R. Brion; Kill, Joshua Y.Effects of an exotic prey species on a native specialist: example of the snail kite
Despite acknowledging that exotic species can exhibit tremendous influence over native populations, few case studies have clearly demonstrated the effects of exotic prey species on native predators. We examined the effects of the recently introduced island apple snail (Pomacea insularum) on the foraging behavior and energetics of the endangered...
Cattau, Christopher E.; Martin, J.; Kitchens, Wiley M.