Open Access. Powered by Scholars. Published by Universities.®

Life Sciences Commons

Open Access. Powered by Scholars. Published by Universities.®

Articles 1 - 28 of 28

Full-Text Articles in Life Sciences

Livestock Producers' Perceptions Of The American Black Vulture Conflict In The Midwestern United States, Marian L. Wahl, Brooke Mcwherter, Patrick A. Zollner, Zhao Ma, Grant C. Burcham, Lee A. Humberg, Brian M. Kluever Jan 2023

Livestock Producers' Perceptions Of The American Black Vulture Conflict In The Midwestern United States, Marian L. Wahl, Brooke Mcwherter, Patrick A. Zollner, Zhao Ma, Grant C. Burcham, Lee A. Humberg, Brian M. Kluever

USDA Wildlife Services: Staff Publications

Human‐wildlife interactions are present wherever both humans and wildlife are found. Interactions can be positive or negative for humans and can include impacts that range from damage to property, agriculture, health and human safety, to emotional effects. Livestock‐wildlife interactions form a major component of human‐wildlife conflicts with foci often centered on the implications of livestock predation by wildlife. While most vulture species are obligate scavengers, several species, including the American black vulture (Coragyps atratus), may attack weak or newborn livestock. Black vulture populations and distributions are expanding in the Midwestern U.S., and attacks create a novel problem for …


Predator Telemetry Informs Temporal And Spatial Overlap With Stocked Salmonids In Lake Huron, David G. Fielder, Todd A. Hayden, Thomas R. Binder, Brian S. Dorr, Heidi A. Currier Jan 2023

Predator Telemetry Informs Temporal And Spatial Overlap With Stocked Salmonids In Lake Huron, David G. Fielder, Todd A. Hayden, Thomas R. Binder, Brian S. Dorr, Heidi A. Currier

USDA Wildlife Services: Staff Publications

Double-Crested Cormorants (Phalacrocorax auratus), Walleyes (Sander vitreus), and Lake Trout (Salvelinus namaycush) are migratory predators that undergo extensive movements in Lake Huron. Stocking of juvenile salmonid fish (Oncorhynchus and Salmo sp.) is an important component of fishery management in Lake Huron and assessing the spatial and temporal extent of predator movements is a useful consideration for determining when and where to stock juvenile fish to reduce predation and maximize survival. Previous investigation indicated that some Walleyes migrate to the main basin of Lake Huron in spring from Saginaw Bay. Similarly, telemetry studies of Lake Trout movement in Lake Huron have …


Science‐Driven Guidelines Needed To Better Manage And Conserve Black Vultures In North America, Scott A. Rush, Neil J. Buckley, Patrick A. Zollner, Bryan M. Kluever, Brooke Mcwherter, Grant C. Burcham, Zhao Ma, Marian L. Wahl, Adrián Naveda‐Rodríguez Jan 2023

Science‐Driven Guidelines Needed To Better Manage And Conserve Black Vultures In North America, Scott A. Rush, Neil J. Buckley, Patrick A. Zollner, Bryan M. Kluever, Brooke Mcwherter, Grant C. Burcham, Zhao Ma, Marian L. Wahl, Adrián Naveda‐Rodríguez

USDA Wildlife Services: Staff Publications

Black vultures (Coragyps atratus) provide invaluable ecological services through disposal of carrion and the mobilization of energy within the landscape. Human‐wildlife conflicts with these birds have increased as populations have grown and the species distribution has expanded. We identify critical science needed to understand conflict between black vultures and humans to inform effective management of this species in North America. It is imperative that diagnostic criteria supporting the identification of the impacts of black vulture on livestock be standardized and verified. Management guidelines that take these criteria into account will enable reduction in the potential for black‐vulture‐farmer conflict …


Stress And Predation Impacts On North American Quail Translocations, Curt A. Vandenberg, Sarah A. Currier, Jeffrey G. Whitt, Kelly S. Reyna Sep 2022

Stress And Predation Impacts On North American Quail Translocations, Curt A. Vandenberg, Sarah A. Currier, Jeffrey G. Whitt, Kelly S. Reyna

National Quail Symposium Proceedings

Translocations have been used in attempts to bolster or restore native quail populations for >150 years, often with little success. However, with some northeastern United States quail populations undetectable or extirpated, and others across the United States on the extreme decline, translocation as a tool for quail population restoration is becoming increasingly popular. Two factors contributing to translocation failure are physiological stress and predation. Chronic stress associated with translocations can result in weight loss, reduced immune system function, suppressed reproduction, and an altered fight-or-flight response. These stress-induced responses increase vulnerability to predation, the primary cause of quail mortality. Here, we …


Diurnal Occurrence Of Great-Horned Owls On Northern Bobwhite Hunting Properties In Southwest Georgia, Justin A. Rectenwald, Philip M. Coppola, Theron M. Terhune Ii, D. Clay Sisson, James A. Martin Sep 2022

Diurnal Occurrence Of Great-Horned Owls On Northern Bobwhite Hunting Properties In Southwest Georgia, Justin A. Rectenwald, Philip M. Coppola, Theron M. Terhune Ii, D. Clay Sisson, James A. Martin

National Quail Symposium Proceedings

Understanding interactions between prey species and their predators is essential to discerning the ecology and management fundamentals of a species. Great-horned owls (Bubo virginianus) have long been considered an opportunistic predator of northern bobwhite (Colinus virginianus; hereafter, bobwhite) and recent studies have demonstrated that bobwhite survival is reduced at higher great-horned owl densities (Rectenwald et al. 2021). Managers on quail properties often mechanically remove live oak (Quercus virginiana) hammocks as part of larger predation management plans to reduce the amount of suitable predator habitat. While scattered live oaks are typically left for aesthetic purposes, …


Factors Influencing Survival Rates Of Pronghorn Fawns In Idaho, Brett R. Panting, Eric M. Gese, Mary M. Conner, Scott Bergen Jan 2021

Factors Influencing Survival Rates Of Pronghorn Fawns In Idaho, Brett R. Panting, Eric M. Gese, Mary M. Conner, Scott Bergen

USDA Wildlife Services: Staff Publications

Pronghorn (Antilocapra americana) occur throughout western North America. In Idaho, USA, following intensive hunting to reduce crop depredations in the late 1980s, pronghorn populations have not rebounded to desired levels. Because neonatal survival in ungulates is one factor limiting population growth, we evaluated cause‐specific mortality and the influence of intrinsic and extrinsic factors on survival rates of 217 radio‐collared pronghorn fawns across 3 study areas in Idaho during 2015–2016. For intrinsic variables, we determined the sex and body mass index (BMI) for each fawn. For extrinsic variables, we determined the abundance of predators and alternate prey, estimated the …


Economic Effects Of Predation By Scaup On Baitfish And Sportfish Farms, Carole R. Engle, Stephen Clements, Brian S. Dorr, J. Brian Davis, Luke A. Roy, Anita M. Kelly Jan 2021

Economic Effects Of Predation By Scaup On Baitfish And Sportfish Farms, Carole R. Engle, Stephen Clements, Brian S. Dorr, J. Brian Davis, Luke A. Roy, Anita M. Kelly

USDA Wildlife Services: Staff Publications

Fish-eating birds have been found to consume baitfish and sportfish raised on farms in the United States. Understanding the on-farm economic effects of such wildlife conflicts is essential for wildlife management agencies to make informed decisions. Lesser scaup, while not widely considered a fisheating bird, will consume farmed fish. Baitfish and sportfish farms in Arkansas (the major baitfish and sportfish producingstate in the U.S.) were surveyed to gather data on the cost of protecting farm crops from scaup. The values of lost sales revenue from the various species of baitfish and sportfish consumed by scaup were estimated based on a …


Conflict, Coexistence, Or Both? Cougar Habitat Selection, Prey Composition, And Mortality In A Multiple-Use Landscape, David C. Stoner, Mark A. Ditmer, Dustin L. Mitchell, Julie K. Young, Michael L. Wolfe Jan 2021

Conflict, Coexistence, Or Both? Cougar Habitat Selection, Prey Composition, And Mortality In A Multiple-Use Landscape, David C. Stoner, Mark A. Ditmer, Dustin L. Mitchell, Julie K. Young, Michael L. Wolfe

USDA Wildlife Services: Staff Publications

Western North America is experiencing remarkable human population growth and land-use change. Irrigation and associated cultivation have led to colonization of urban-wildland interface (UWI) environments by mule deer (Odocoileus hemionus), and consequently, cougars (Puma concolor). In the wake of these changes, human-wildlife conflicts have increased in tandem with questions about long-term species conservation. To address these concerns, we fit 79 cougars with radio-telemetry collars in the Oquirrh Mountains near Salt Lake City, Utah (2002–2010). Our goal was to evaluate variation in cougar habitat selection, diet, and cause-specific mortality in a landscape dominated by urban, military, and industrial activities. We used …


Effects Of Freshwater Crayfish On Influenza A Virus Persistence In Water, J. Jeffrey Root, Jeremy W. Ellis, Susan A. Shriner Jul 2020

Effects Of Freshwater Crayfish On Influenza A Virus Persistence In Water, J. Jeffrey Root, Jeremy W. Ellis, Susan A. Shriner

USDA Wildlife Services: Staff Publications

Several investigations have recently assessed the ability of some aquatic invertebrates to act as tools for avian influenza A virus (IAV) surveillance as well as their potential role(s) in IAV ecology. Because of this, as well as the high IAV seroprevalence rates noted in select mesocarnivores that commonly inhabit aquatic and semi-aquatic habitats, we evaluated the effects that freshwater crayfish have on IAV in water at three dose levels and monitored for the presence of IAV in crayfish tissues (gill and green gland) and haemolymph at multiple time points. At relatively high, medium 432 and low (approximately 10 , 10 …


Estimates Of Calf Survival And Factors Influencing Roosevelt Elk Mortality In Northwestern California, Erin Nigon Jan 2020

Estimates Of Calf Survival And Factors Influencing Roosevelt Elk Mortality In Northwestern California, Erin Nigon

Cal Poly Humboldt theses and projects

Survival of juvenile ungulates is known to be highly variable, yet it is fundamental to understanding the dynamics and trends of wildlife populations. Factors influencing calf survival are poorly understood in northwestern California where Roosevelt elk (Cervus canadensis roosevelti) are known to exist. The objectives of this study were 1) to estimate summer and annual survival rates and determine recruitment rates for Roosevelt elk calves in the area, 2) to evaluate differences in calf survival by examining the effects of individual and population level covariates on summer and annual calf survival, 3) to identify factors influencing the timing …


Changes In Hatchery Subsidies Of Chinook Salmon In The Salish Sea: Implications For Predators, Fisheries, And Conservation, Benjamin Nelson, Eric John Ward, Ole Shelton, Joseph H. Anderson Apr 2018

Changes In Hatchery Subsidies Of Chinook Salmon In The Salish Sea: Implications For Predators, Fisheries, And Conservation, Benjamin Nelson, Eric John Ward, Ole Shelton, Joseph H. Anderson

Salish Sea Ecosystem Conference

Historically, salmon hatcheries were designed to increase fishery production and to recover depleted native populations. As demands of human protein consumption increase and wild populations continue to decline due to anthropogenic impacts like climate change and habitat loss, hatcheries and stocking programs will be called on to provide food security and to supplement threatened populations. Since 1950 over 3.7 billion Chinook salmon have been released into the Salish Sea and its tributaries in Washington State and southern British Columbia. However, relatively little research has been conducted that considers the impact of hatchery subsidies on estuarine and nearshore marine ecosystems in …


Interannual Variation In Early Marine Survival Patterns Of Puget Sound Steelhead Smolts Indicates Shifting Predation Pressures, Barry A. Berejikian, Megan Moore, Steve Jeffries Apr 2018

Interannual Variation In Early Marine Survival Patterns Of Puget Sound Steelhead Smolts Indicates Shifting Predation Pressures, Barry A. Berejikian, Megan Moore, Steve Jeffries

Salish Sea Ecosystem Conference

Marine survival of steelhead smolts during their two week migration from river mouths to the Strait of Juan de Fuca has been estimated at 20% or less for several populations originating in Puget Sound. Low survival rates likely reduce overall smolt-to-adult return rates and limit recovery of Puget Sound steelhead populations. Harbor seals are generalist predators known to eat juvenile salmon in the Salish Sea. Harbor seals were captured in 2014 (12 seals) and 2016 (16 seals) and outfitted with acoustic telemetry receivers and GPS tags to quantify likely predation events and estimate foraging area overlap with acoustically tagged steelhead …


Foraging Opportunity: A Method Of Monitoring Shorebird Migration And Overwintering Sites In A Changing Environment, James Rourke, Wendell Challenger, Ron Ydenberg Apr 2018

Foraging Opportunity: A Method Of Monitoring Shorebird Migration And Overwintering Sites In A Changing Environment, James Rourke, Wendell Challenger, Ron Ydenberg

Salish Sea Ecosystem Conference

Roberts Bank within the Fraser River estuary, BC contains important migratory stopover and overwintering habitat for shorebirds such as the western sandpiper (Calidris mauri) and the Pacific dunlin (Calidris alpina pacifica). Shorebirds are especially abundant during northward migration, with single-day counts numbering into the hundreds of thousands of birds. Previous research and ecological theory have demonstrated that site usage by shorebirds is influenced by numerous factors, including prey availability and predation risk. We developed a concept termed “foraging opportunity” that quantifies shorebird food availability (biofilm, meiofauna, and macrofauna) in relation to predation danger from hunting falcons. Foraging opportunity was determined …


Mink Predation Of Brown Trout In A Black Hills Stream, Jake Davis, Jerry W. Wilhite, Steven R. Chipps Jun 2016

Mink Predation Of Brown Trout In A Black Hills Stream, Jake Davis, Jerry W. Wilhite, Steven R. Chipps

The Prairie Naturalist

In the early 2000’s, declines in the brown trout (Salmo trutta) fishery in Rapid Creek, South Dakota, caused concern for anglers and fisheries managers. We conducted a radio telemetry study in 2010 and 2011 to identify predation mortality associated with mink, using hatchery-reared (2010) or wild (2011) brown trout. Estimated predation rates by mink (Mustela vison) on radio-tagged brown trout were 30% for hatchery fish and 32% for wild fish. Size frequency analysis revealed that the size distribution of brown trout lost to predation was similar to that of other, radio-tagged brown trout. In both years, a higher proportion of …


Potential For Biocontrol Of Environmental Vibrio Spp. By Predatory Bacteria Bacteriovorax, Patrick Tennis Apr 2015

Potential For Biocontrol Of Environmental Vibrio Spp. By Predatory Bacteria Bacteriovorax, Patrick Tennis

OES Theses and Dissertations

The scale of predator-prey interactions varies from the iconic (e.g., lions and gazelles) to the microscopic (e.g., protists and bacteria). Bdellovibrio-and-like-organisms (BALOs) are bacteria that prey upon other Gram-negative bacteria, including pathogens. In particular, the halophilic genus Vibrio, many species of which are disease agents, has been shown to be susceptible to attack by BALOs. One motivation of the present research is to assess the potential for biocontrol of Vibrio by Bacteriovorax. This investigation is the first to test the susceptibility of Vibrio strains (n = 26) originating from a variety of geographic locations to predation by …


Nest Success And Habitat Choice Of Wilson's Plovers In Tom Yawkey Wildlife Center Heritage Preserve, South Carolina, Elizabeth Zinsser May 2013

Nest Success And Habitat Choice Of Wilson's Plovers In Tom Yawkey Wildlife Center Heritage Preserve, South Carolina, Elizabeth Zinsser

All Theses

Little is known about the reproductive ecology of Wilson's Plover (Charadrius wilsonia). I conducted a study of nest site selection and nest success at a critical breeding area in South Carolina, USA. Data from other coastal nesting birds in the region suggest that a suite of environmental factors including flooding and predation may limit nest success in this region. To assess nest success rates of Wilson's Plovers in an area with limited human disturbance I monitored 72 nests during 2012 and 2013 on South Island and Sand Island located in Tom Yawkey Wildlife Center and Heritage Preserve. I measured environmental …


Cougar Predation Behavior In North-Central Utah, Dustin L. Mitchell May 2013

Cougar Predation Behavior In North-Central Utah, Dustin L. Mitchell

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Today’s ability to apply global positioning systems (GPS) collars to wild animals and track their movements, without inadvertently disrupting their daily routine, is a major benefit to wildlife research. Cougars are carnivorous predators that have been identified as being one of several possible causes for recent mule deer population declines throughout the Western United States. Past cougar predation studies have relied on snow tracking, radio-collar tracking, and modeling techniques to estimate cougar prey use and predation rates. These methods rely heavily on weather conditions, logistical availabilities, and broad assumptions, which have led to a wide range of predation rate estimates. …


Review Of The Negative Influences Of Non-Native Salmonids On Native Fish Species, Kelly C. Turek, Mark A. Pegg, Kevin L. Pope Apr 2013

Review Of The Negative Influences Of Non-Native Salmonids On Native Fish Species, Kelly C. Turek, Mark A. Pegg, Kevin L. Pope

Nebraska Cooperative Fish and Wildlife Research Unit: Staff Publications

Non-native salmonids are often introduced into areas containing species of concern, yet a comprehensive overview of the short- and long-term consequences of these introductions is lacking in the Great Plains. Several authors have suggested that non-native salmonids negatively influence species of concern. The objective of this paper is to review known interactions between non-native salmonids and native fishes, with a focus on native species of concern. After an extensive search of the literature, it appears that in many cases non-native salmonids do negatively influence species of concern (e.g., reduce abundance and alter behavior) via different mechanisms (e.g., predation and competition). …


Impacts Of The Spotted Spiny Lobster (Panulirus Guttatus) On The Long-Spined Sea Urchin (Diadema Antillarum) And Patch Reef Communities In The Florida Keys, Meredith D. Kintzing Jan 2010

Impacts Of The Spotted Spiny Lobster (Panulirus Guttatus) On The Long-Spined Sea Urchin (Diadema Antillarum) And Patch Reef Communities In The Florida Keys, Meredith D. Kintzing

Biological Sciences Theses & Dissertations

Caribbean coral reefs have undergone a phase shift from a system dominated by corals to one where algae are pervasive. This shift was precipitated by the loss of herbivores, including the mass mortality of the long spined sea urchin (Diadema antillarum), coupled with disease and the recruitment failure of hermatypic corals. Diadema populations have recovered in some areas of the Caribbean, but are still below historical levels in the Florida Keys, likely due to low larval supply coupled with predation on juveniles. Lobsters are sea urchin predators in other systems and the spotted spiny lobster (Panulirus guttatus …


Absence Of Predation Eliminates Coexistence: Experience From The Fish-Zooplankton Interface, Z. M. Gilwicz, Wayne A. Wurtsbaugh, E. Szymansk Jan 2010

Absence Of Predation Eliminates Coexistence: Experience From The Fish-Zooplankton Interface, Z. M. Gilwicz, Wayne A. Wurtsbaugh, E. Szymansk

Watershed Sciences Faculty Publications

Examples from fishless aquatic habitats show that competition among zooplankton for resources instigates rapid exclusion of competitively inferior species in the absence of fish predation, and leads to resource monopolization by the superior competitor. This may be a single species or a few clones with large body size: a cladoceran such as Daphnia pulicaria, or a branchiopod such as Artemia franciscana, each building its population to a density far higher than those found in habitats with fish. The example of zooplankton from two different fish-free habitats demonstrates the overpowering force of fish predation by highlighting the consequences of its absence. …


Patterns Of Bison Hair Use In Nests Of Tallgrass Prairie Birds, Bryan R. Coppedge Dec 2009

Patterns Of Bison Hair Use In Nests Of Tallgrass Prairie Birds, Bryan R. Coppedge

The Prairie Naturalist

I examined patterns of bison (Bison bison L.) hair use by passerine birds nesting in the Tallgrass Prairie Preserve, Osage County, Oklahoma, 2002-2004. I collected and dissected 103 nests of 15 species into their constituent components. Nests were predominately composed of herbaceous material such as grass stems and leaves. Woody material and mud were rarely used. Bison hair was the most prominent zoological material used in nests, with lesser amounts and occurrence of arthropod silk, snake skin, feathers, jack rabbit (Lepus californicus Oray) fur, and man-made materials such as cellophane and string. At least one nest of 13 …


Low Reproductive Success Of Mallards In A Grassland-Dominated Landscape In The Sandhills Of Nebraska, Johann A. Walker, Zach J. Cunningham, Mark P. Vrtiska, Scott E. Stephens, Larkin Powell Mar 2008

Low Reproductive Success Of Mallards In A Grassland-Dominated Landscape In The Sandhills Of Nebraska, Johann A. Walker, Zach J. Cunningham, Mark P. Vrtiska, Scott E. Stephens, Larkin Powell

The Prairie Naturalist

The Sandhills of Nebraska comprise approximately 5,000,000 ha of native grassland interspersed with numerous groundwater-fed wetlands. A substantial population of the mallard (Anas platyrhynchos) nests in this region. Previous investigations of nest survival probability of ducks in the Sandhills have estimated surprisingly low rates of nest survival for a grassland-dominated landscape. These investigations were conducted on public lands and most nest searching took place near wetlands where activity of nest predators might be highest. We predicted that mallards would nest at varying distances from wetlands and that survival probability of a representative sample of duck nests would increase …


Trampling, Peeling And Nibbling Mussels: An Experimental Assessment Of Mechanical And Predatory Damage To Shells Of Mytilus Trossulus (Mollusca: Mytilidae), Carlos E. Cintra-Buenrostro Jan 2007

Trampling, Peeling And Nibbling Mussels: An Experimental Assessment Of Mechanical And Predatory Damage To Shells Of Mytilus Trossulus (Mollusca: Mytilidae), Carlos E. Cintra-Buenrostro

School of Earth, Environmental, and Marine Sciences Faculty Publications and Presentations

Shell damage, if properly recognized, can provide information about biotic interactions between molluscs and their predators. However, it can be difficult to distinguish predatory damage from mechanical breakage, thus making interpretation of damaged modern and fossil shells problematic. To establish a clear-cut distinction between antemortem predatory crab damage and ante- and postmortem mechanical damage in Mytilus trossulus shells, a combined field and experimental approach was used. Mussels were exposed to predation by crabs, tumbled-live, tumbled-dead, and trampled. After 100 h of tumbling, live-collected mussel shells were abraded and disarticulated but not otherwise damaged. Eight percent of the dead-collected shells were …


An Examination Of Predatory Pressures On Piping Plovers Nesting At Breezy Point, New York, Brook Lauro, John Tanacredi Ph.D. Dec 2002

An Examination Of Predatory Pressures On Piping Plovers Nesting At Breezy Point, New York, Brook Lauro, John Tanacredi Ph.D.

Faculty Works: CERCOM

This study examines predatory threats to Piping Plovers (Charadrius melodus) nesting at Breezy Point, Gateway National Recreation Area, New York. Several methods used include: 1) an evaluation of reproductive success data with documentation of predation to eggs and chicks, 2) predator surveys, and 3) an artificial nest study. The range of breeding pairs nesting from 1988-1996 was 11-19, with an average of 15.8 (SE ± 0.79) pairs/season. The average number of eggs hatched and chicks fledged per year for pairs was 2.2 ± 0.23 and 0.8 ± 0.16 respectively. Reasons for egg losses often went undetected (68%) but …


Neurological Effects On Startle Response And Escape From Predation By Medaka Exposed To Organic Chemicals, Steven P. Bradbury, Richard W. Carlson, Robert A. Drummond, Dean E. Hammermeister Sep 1998

Neurological Effects On Startle Response And Escape From Predation By Medaka Exposed To Organic Chemicals, Steven P. Bradbury, Richard W. Carlson, Robert A. Drummond, Dean E. Hammermeister

Steven P. Bradbury

Simultaneous electrophysiological and behavioral studies were performed on 21–32 day old juvenile medaka (Oryzias latipes) exposed at sublethal concentrations to organic chemicals representing various modes of action. Non-invasive recordings were made of the electrical impulses generated within giant neuronal Mauthner cells, associated interneurons and motoneurons, and axial musculature, all of which initiate the startle or ‘escape’ response in fish. Timing in ms between these electrical sequelae was measured for each fish before and after 24 and 48 h exposure to a chemical. Carbaryl and phenol affected Mauthner cell to motoneuron transmission while chlorpyrifos, carbaryl, phenol and 2,4-dinitrophenol (DNP) showed neuromuscular …


Prey Depletion By Odonate Larvae: Combining Evidence From Multiple Field Experiments, Clay L. Pierce, Dan M. Johnson, Thomas H. Martin, Charles N. Watson, Robert E. Bohanan, Philip H. Crowley Oct 1987

Prey Depletion By Odonate Larvae: Combining Evidence From Multiple Field Experiments, Clay L. Pierce, Dan M. Johnson, Thomas H. Martin, Charles N. Watson, Robert E. Bohanan, Philip H. Crowley

Clay L. Pierce

In this paper we re-analyze previously published data regarding the response of several prey populations to manipulation of predaceous larval dragonfly (Insecta: Odonata) densities in four separate field enclosure experiments. Using a computer-intensive "rerandomization" approach to testing hypotheses, we show that the individual experiments were not sufficiently powerful to consistently reject false null hypotheses. Combining the data from three comparable experiments, we can enhance the power associated with such tests. Three prey categories (Trichoptera, Oligochaeta, and large Cladocera), constituting less than one-third of the typical odonate diet, were found to be consistently depleted in enclosures with odonate larvae; but the …


Importance Of Predation By Adult Trout On Mortality Rates Of Fingerling Rainbow Trout Stocked In East Canyon Reservoir, Utah, Wayne A. Wurtsbaugh Jan 1987

Importance Of Predation By Adult Trout On Mortality Rates Of Fingerling Rainbow Trout Stocked In East Canyon Reservoir, Utah, Wayne A. Wurtsbaugh

Watershed Sciences Faculty Publications

Personnel from Utah State University, working in cooperation with the Utah Division of Wildlife Resources and the Utah Cooperative Fish and Wildlife Research Unit, are attempting to determine various sources of mortality of fingerling rainbow trout (Salmo gairdneri) stocked into mid-elevation reservoirs in the State. Returns of planted fish are often much below desired levels. Angler surveys indicate that in East Canyon Reservoir, fishermen harvest only about 30% of the fingerling trout stocked, and this is a much higher return than in many other waters.


Behavior And Ecological Interactions Of Larval Odonata, Clay L. Pierce, Philip H. Crowley, Dan M. Johnson Oct 1985

Behavior And Ecological Interactions Of Larval Odonata, Clay L. Pierce, Philip H. Crowley, Dan M. Johnson

Clay L. Pierce

Enallagma aspersum and E. traviatum (Odonata: Coenagrionidae) are the most abundant larval odonates in Bays Mountain Park (Sullivan County, Tennessee, USA), although their spatial distributions are essentially nonoverlapping. E. traviatum coexists with insectivorous fish in a small lake, whereas E. aspersum is restricted to a small fishless pond nearby. Behavioral observations revealed that E. aspersum larvae were more active than E. traviatum, and tended to occupy more conspicuous positions. E. aspersum also engaged in more confrontations than E. traviatum, especially at higher density. In laboratorye xperimentsw ith juvenile bluegills( Lepomism acrochirusa) s predators,E . aspersum larvae were more vulnerable to …