Physical Sciences and Mathematics Commons^™

Sustainable Irrigation Based On Co-Regulation Of Soil Water Supply And Atmospheric Evaporative Demand, Jingwen Zhang, Kaiyu Guan, Bin Peng, Ming Pan, Wang Zhou, Chongya Jiang, Hyungsuk Kimm, Trenton E. Franz, Robert F. Grant, Yi Yang, Daran R. Rudnick, Derek M. Heeren, Andrew E. Suyker, William L. Bauerle, Grace L. Miner

School of Natural Resources: Faculty Publications

Irrigation is an important adaptation to reduce crop yield loss due to water stress from both soil water deficit (low soil moisture) and atmospheric aridity (high vapor pressure deficit, VPD). Traditionally, irrigation has primarily focused on soil water deficit. Observational evidence demonstrates that stomatal conductance is co-regulated by soil moisture and VPD from water supply and demand aspects. Here we use a validated hydraulically-driven ecosystem model to reproduce the co-regulation pattern. Specifically, we propose a plant-centric irrigation scheme considering water supply-demand dynamics (SDD), and compare it with soil-moisture-based irrigation scheme (management allowable depletion, MAD) for continuous maize cropping systems in …

Magnitude And Uncertainty Of Nitrous Oxide Emissions From North America Based On Bottom-Up And Top-Down Approaches: Informing Future Research And National Inventories, R. Xu, Hanqin Tian, N. Pan, R. L. Thompson, J. G. Canadell, E. A. Davidson, C. Nevison, W. Winiwarter, H. Shi, S. Pan, J. Chang, P. Ciais, Shree Dangal, A. Ito, R. B. Jackson, F. Joos, R. Lauerwald, S. Lienert, T. Maavara, D. B. Millet, P. A. Raymond, P. Regnier, F. N. Tubiello, N. Vuichard, K. C. Wells, C. Wilson, J. Yang, Y. Yao, S. Zaehle, F. Zhou

School of Natural Resources: Faculty Publications

We synthesized N₂O emissions over North America using 17 bottom-up (BU) estimates from 1980– 2016 and five top-down (TD) estimates from 1998 to 2016. The BU-based total emission shows a slight increase owing to U.S. agriculture, while no consistent trend is shown in TD estimates. During 2007–2016, North American N₂O emissions are estimated at 1.7 (1.0–3.0) Tg N yr⁻¹ (BU) and 1.3 (0.9–1.5) Tg N yr⁻¹ (TD). Anthropogenic emissions were twice as large as natural fluxes from soil and water. Direct agricultural and industrial activities accounted for 68% of total anthropogenic emissions, 71% of …

Ten Simple Rules For Creating A Scientific Web Application, Jessica L. Burnett, Renee Dale, Chung-Yi Hou, Gabriela Palomo-Muoz, Kaitlin Stack Whitney, Steve Aulenbach, Robert Sky Bristol, Denis Valle, Tristan P. Wellman

School of Natural Resources: Faculty Publications

The use of scientific web applications (SWApps) across biological and environmental sciences has grown exponentially over the past decades or so. Although quantitative evidence for such increased use in practice is scant, collectively, we have observed that these tools become more commonplace in teaching, outreach, and in science coproduction (e.g., as decision support tools). Despite the increased popularity of SWApps, researchers often receive little or no training in creating such tools. Although rolling out SWApps can be a relatively simple and quick process using modern, popular platforms like R shiny apps or Tableau dashboards, making them useful, usable, and sustainable …

Soil Microbial Community Dynamics In Response To Prescribed Extreme Fires Following Juniperus Virginiana Invasion In The Loess Canyons Of Nebraska, Julie A. Fowler

School of Natural Resources: Dissertations, Theses, and Student Research

In Nebraska and other regions of the Great Plains, the conifer Juniperus virginiana (eastern redcedar) is converting grasslands to dense woodlands. This is driven by the interacting drivers of fire suppression, altered grazing regimes, climate change and other anthropogenic factors, impacting the provisioning of ecosystem services. This vegetation state transition modifies water resource regulation and biogeochemical cycles leading to altered edaphic properties including soil microbial community composition. To restore these grasslands and control J. virginiana spread, prescribed extreme burns are implemented as a management tool through local prescribed burn associations. We hypothesized that the alternative state transition to dense J. …

Constraints To Waterfowl Hunting By Hunters And Anglers In The Central United States, Matthew P. Hinrichs, Matthew P. Gruntorad, Julia A. Nawrocki, Mark P. Vrtiska, Mark A. Pegg, Christopher J. Chizinski

School of Natural Resources: Faculty Publications

Waterfowl hunting participation has been on the decline since the mid‐1980s. We used a web‐based survey to better understand waterfowl hunting constraints (i.e., factors that limit or prohibit participation and enjoyment in leisure activities) among hunters and anglers that hunted or did not hunt waterfowl in the central United States. Forty‐eight constraint items were condensed into 10 constraint factors: Rules and Regulations, Waterfowl Identification, Cost, Waterfowl Hunting Skills, Land Access and Permissions, Interference by Other Hunters, Travel, Social, Waterfowl Populations, and Views of Others. We observed significant effects of both state of residence and activity type (i.e., frequent waterfowl hunters, …

A Physiological Signal Derived From Sun-Induced Chlorophyll Fluorescence Quantifies Crop Physiological Response To Environmental Stresses In The U.S. Corn Belt, Hyungsuk Kimm, Kaiyu Guan, Chongya Jiang, Guofang Miao, Genghong Wu, Andrew Suyker, Elizabeth A. Ainsworth, Carl J. Bernacchi, Christopher M. Montes, Joseph A. Berry, Xi Yang, Christian Frankenberg, Min Chen, Philipp Köhler

School of Natural Resources: Faculty Publications

Sun-induced chlorophyll fluorescence (SIF) measurements have shown unique potential for quantifying plant physiological stress. However, recent investigations found canopy structure and radiation largely control SIF, and physiological relevance of SIF remains yet to be fully understood. This study aims to evaluate whether the SIF-derived physiological signal improves quantification of crop responses to environmental stresses, by analyzing data at three different spatial scales within the U.S. Corn Belt, i.e. experiment plot, field, and regional scales, where ground-based portable, stationary and space-borne hyperspectral sensing systems are used, respectively. We found that, when controlling for variations in incoming radiation and canopy structure, crop …

Landscape Transformations Produce Favorable Roosting Conditions For Turkey Vultures And Black Vultures, Jacob E. Hill, Kenneth F. Kellner, Bryan M. Kluever, Michael L. Avery, John S. Humphrey, Eric A. Tillman, Travis L. Devault, Jerrold L. Belant

USDA Wildlife Services: Staff Publications

Recent increases in turkey vulture (Cathartes aura) and black vulture (Coragyps atratus) populations in North America have been attributed in part to their success adapting to human-modified landscapes. However, the capacity for such landscapes to generate favorable roosting conditions for these species has not been thoroughly investigated. We assessed the role of anthropogenic and natural landscape elements on roosting habitat selection of 11 black and 7 turkey vultures in coastal South Carolina, USA using a GPS satellite transmitter dataset derived from previous research. Our dataset spanned 2006–2012 and contained data from 7916 nights of roosting. Landscape …

Towards A More Comprehensive Understanding Of Wild Pig (Sus Scrofa) Impacts On Agricultural Producers: Insights From A Texas Case Study, Keith M. Carlisle, Nicole Didero, Sophie Mckee, Julie Elser, Stephanie A. Shwiff

USDA Wildlife Services: Staff Publications

This research investigates the impacts of invasive wild pigs (Sus scrofa Linneaus) on agricultural producers in Texas, with the aim of identifying and describing all categories of wild pig impacts and quantifying the extent of producers’ over- or underestimation of their total wild pig-related costs in 2018, as compared to calculations based upon data subsequently provided by the producers about individual wild pig-related costs and losses. Based on interviews with 23 producers in 16 Texas counties, we identified more than 20 discrete categories of negative impacts and negligible positive impacts associated with wild pigs. Among them were categories that have …

Sex And Nest Type Influence Avian Blood Parasite Prevalence In A High-Elevation Bird Community, Marina D. Rodriguez, Paul F. Doherty, Antoinette J. Piaggio, Kathryn P. Huyvaert

USDA Wildlife Services: Staff Publications

Background: The prevalence of avian haemosporidian parasites and the factors influencing infection in the Colorado Rocky Mountains are largely unknown. With climate change expected to promote the expansion of vector and avian blood parasite distributions, baseline knowledge and continued monitoring of the prevalence and diversity of these parasites is needed.

Methods: Using an occupancy modeling framework, we conducted a survey of haemosporidian parasite species infecting an avian community in the Colorado Rocky Mountains in order to estimate the prevalence and diversity of blood parasites and to investigate species-level and individual-level characteristics that may influence infection.

Results: We estimated the prevalence …

Reproductive Success Of Captive-Reared Allegheny Woodrats (Neotoma Magister) Released Into Genetically Depauperate Populations, Miracle M. Davis, Timothy J. Smyser, Scott A. Johnson, Joseph Duchamp, Jeffery L. Larkin, Robert K. Swihart, Jacqueline M. Doyle

USDA Wildlife Services: Staff Publications

Habitat fragmentation and degradation have led to a proliferation of small and isolated populations that are vulnerable to genetic erosion. Reduction in habitat and concomitant declines in population connectivity can expediate the collapse of species that exist as natural metapopulations. In recent years, Allegheny woodrats (Neotoma magister) have experienced local extirpations and declines in genetic diversity across their range due to disease-related mortality, reduced food availability, and disruption of connectivity among subpopulations. In response, we developed a captive-breeding program to facilitate genetic management of isolated woodrat populations in Indiana. Between 2010 and 2012, 27 captive-reared individuals were released to four …

Economic Estimates Of Wild Hog (Sus Scrofa) Damage And Control Among Young Forest Plantations In Alabama, Micah Fern, Rebecca Barlow, Chris Slootmaker, John Kush, Stephanie Shwiff, Larry Teeter, Jim Armstrong

USDA Wildlife Services: Staff Publications

Operating as ecological engineers, the increased distribution and abundance of wild hogs (Sus scrofa) has caused considerable socio-economic impacts. The international scope of economic research providing wild hog damage estimates are often confined to agricultural crops, while damage estimates among forest plantations are lacking. In Alabama, private landowners hold the majority of timberland acreage and are less equipped to absorb financial losses from wild hog damage than their industrial counterparts. A survey was conducted to estimate the economic impact of wild hogs, namely costs of damage and control, to privately owned forestlands. The survey was distributed in the …

Responses Of Turkey Vultures To Unmanned Aircraft Systems Vary By Platform, Morgan B. Pfeiffer, Bradley F. Blackwell, Thomas W. Seamans, Bruce N. Buckingham, Joshua L. Hoblet, Patrice E. Baumhardt

USDA Wildlife Services: Staff Publications

A challenge that conservation practitioners face is manipulating behavior of nuisance species. The turkey vulture (Cathartes aura) can cause substantial damage to aircraft if struck. The goal of this study was to assess vulture responses to unmanned aircraft systems (UAS) for use as a possible dispersal tool. Our treatments included three platforms (fixed-wing, multirotor, and a predator-like ornithopter [powered by flapping flight]) and two approach types (30 m overhead or targeted towards a vulture) in an operational context. We evaluated perceived risk as probability of reaction, reaction time, flight-initiation distance (FID), vulture remaining index, and latency to return. …

Potential Use For Serosurveillance Of Feral Swine To Map Risk For Anthrax Exposure, Texas, Usa, Rachel M. Maison, Courtney F. Pierce, Izabela K. Ragan, Vienna R. Brown, Michael J. Bodenchuk, Richard A. Bowen, Angela M. Bosco-Lauth

USDA Wildlife Services: Staff Publications

Anthrax is a disease of concern in many mammals, including humans. Management primarily consists of prevention through vaccination and tracking clinical-level observations because environmental isolation is laborious and bacterial distribution across large geographic areas diffi cult to confi rm. Feral swine (Sus scrofa) are an invasive species with an extensive range in the southern United States that rarely succumbs to anthrax. We present evidence that feral swine might serve as biosentinels based on comparative seroprevalence in swine from historically defi ned anthrax-endemic and non–anthraxendemic regions of Texas. Overall seropositivity was 43.7% (n = 478), and logistic regression revealed county endemicity …

Deterring Non-Target Birds From Toxic Bait Sites For Wild Pigs, Nathan P. Snow, Joseph M. Halseth, Justin A. Foster, Michael J. Lavelle, Justin W. Fischer, Michael P. Glow, Ingrid A. Messer, Seth M. Cook, Kurt C. Vercauteren

USDA Wildlife Services: Staff Publications

Toxic baiting of wild pigs (Sus scrofa) is a potential new tool for population control and damage reduction in the US. Field trials testing a prototype toxic bait (HOGGONE 2 containing 5% sodium nitrite [SN]), though, revealed that wild pigs spilled small particles of toxic bait outside of bait stations which subsequently created hazards for non-target species that consumed those particles, primarily passerine birds. To deter non-target birds from consuming particles of spilled bait, we tested four deterrents at mock bait sites (i.e., baited with bird seed) in north-central Colorado, USA during April–May 2020. We found a programable, inflatable deterrent …

American Burying Beetle, Plant Richness, And Soil Property Responses To Collapse Of Juniperus Virginiana Woodlands With Fire, Alison Ludwig

Department of Agronomy and Horticulture: Dissertations, Theses, and Student Research

Grasslands are declining in the Great Plains due to land use changes, woody plant encroachment, and loss of historic fire cycles. Prescribed burn associations have utilized prescribed fire to collapse invading woodlands and allow the restoration of grasslands. This fire is considered “extreme” because it is capable of changing the structure and function of an ecosystem. Our study site is the Loess Canyons Experimental Landscape, a long-term, ecoregion-scale experiment to apply prescribed fire across the region to restore grasslands. The Nebraska Natural Legacy Project established the Loess Canyons ecoregion as a Biologically-Unique Landscape in 2005 with the state’s wildlife action …

How Do Genetic Relatedness And Spatial Proximity Shape African Swine Fever Infections In Wild Boar?, Tomasz Podgórski, Kim M. Pepin, Anna Radko, Angelika Podbielska, Magdalena Łyjak, Grzegorz Woźniakowski, Tomasz Borowik

USDA Wildlife Services: Staff Publications

The importance of social and spatial structuring of wildlife populations for disease spread, though widely recognized, is still poorly understood in many host-pathogen systems. In particular, system-specific kin relationships among hosts can create contact heterogeneities and differential disease transmission rates. Here, we investigate how distance-dependent infection risk is influenced by genetic relatedness in a novel host-pathogen system: wild boar (Sus scrofa) and African swine fever (ASF).We hypothesized that infection risk would correlate positively with proximity and relatedness to ASF-infected individuals but expected those relationships to weaken with the distance between individuals due to decay in contact rates and …

Feasibility Discussion Of Potential Carbon Offsetting Options For Nebraska, Andrew Mwape

School of Natural Resources: Faculty Publications

Conclusion

Highlighting the advantages and disadvantages of carbon offsetting options in the context of the state of Nebraska, this discussion shows that the choice and decisions about which option is better than the other depends on the interests at play and expected outcomes of the participation in carbon markets. However, irrespective of the motive to engage in emission reduction projects for carbon marketing, factors such as cost, and project efficiency can never be overlooked. Given the options discussed in this report, Nebraska has a lot of potential for carbon offsetting or emission reduction projects that would not only reduce and …

Correlated Evolution Of Distinct Signals Associated With Increased Social Selection In Female White-Shouldered Fairywrens, John Anthony Jones, Karan J. Odom, Ian R. Hoppe, Doka Nason, Serena Ketaloya, Jordan Karubian

School of Natural Resources: Faculty Publications

Conspicuous female signals have recently received substantial scientific attention, but it remains unclear if their evolution is the result of selection acting on females independently of males or if mutual selection facilitates female change. Species that express female, but not male, phenotypic variation among populations represents a useful opportunity to address this knowledge gap. White-shouldered fairywrens (Malurus alboscapulatus) are tropical songbirds with a well-resolved phylogeny where female, but not male, coloration varies allopatrically across subspecies. We explored how four distinct signaling modalities, each putatively associated with increased social selection, are expressed in two populations that vary in competitive pressure on …

Salient Experiences In Student Development: Impact Of An Undergraduate Stem Teacher Preparation Program, Amie S. Sommers, Kelly Gomez Johnson, Paula Jakopovic, Julio Rivera, Neal Grandgenett, John A. Conrad, William E. Tapprich, Christine E. Cutucache

School of Natural Resources: Faculty Publications

The need for a comprehensive, high-quality pipeline for the development of undergraduate pre-service teachers, especially those that represent a diverse student body, within STEM disciplines is acute. Here, we studied the NoyceSCIENCE program to determine the most impactful experiences offered to undergraduates through the lens of student development theory. We used qualitative coding to analyze data collected from journals (n = 29) written by students of varying backgrounds, and at varying levels within the program (i.e., the Scholar and Intern level) over a 3-year program running period. We observed that faculty mentorship, the ability of undergraduates to mentor others, volunteer …

Monitoring Agroecosystem Productivity And Phenology At A National Scale: A Metric Assessment Framework, Dawn M. Browning, Eric S. Russell, Guillermo E. Ponce-Campos, Nicole Kaplan, Andrew D. Richardson, Bijan Seyednasrollah, Sheri Spiegal, Nicanor Saliendra, Joseph G. Alfieri, John Baker, Carl Bernacchi, Brandon T. Bestelmeyer, David Bosch, Elizabeth H. Boughton, Raoul K. Boughton, Pat Clark, Gerald Flerchinger, Nuria Gomez-Casanovas, Sarah Goslee, Nick M. Haddad, David Hoover, Abdullah Jaradat, Marguerite Mauritz, Gregory W. Mccarty, Gretchen R. Miller, John Sadler, Amartya Saha, Russell L. Scott, Andrew Suyker, Craig Tweedie, Jeffrey D. Wood, Xukai Zhang, Shawn D. Taylor

School of Natural Resources: Faculty Publications

Effective measurement of seasonal variations in the timing and amount of production is critical to managing spatially heterogeneous agroecosystems in a changing climate. Although numerous technologies for such measurements are available, their relationships to one another at a continental extent are unknown. Using data collected from across the Long-Term Agroecosystem Research (LTAR) network and other networks, we investigated correlations among key metrics representing primary production, phenology, and carbon fluxes in croplands, grazing lands, and crop-grazing integrated systems across the continental U.S. Metrics we examined included gross primary productivity (GPP) estimated from eddy covariance (EC) towers and modelled from the Landsat …

Wildlife Responses To Livestock Guard Dogs And Domestic Sheep On Open Range, Daniel Kinka, Jeffrey T. Schultz, Julie K. Young

USDA Wildlife Services: Staff Publications

Domestic sheep (Ovis aries) are an attractant to carnivores; however, sheep are often accompanied by humans and livestock guardian dogs (LGDs; Canis familiaris), which defend sheep from depredation. Sheep also compete directly with wildlife for grazing resources. Although practiced for millennia in much of the world outside North America, the effect that transhumance has on wildlife is poorly understood. To test the effect of sheep bands (sheep, humans, and LGDs) on wildlife, we modeled the detection probability of wild mammals relative to the presence of sheep bands in the Northwestern United States. Sheep band presence was associated …

Mongooses (Urva Auropunctata) As Reservoir Hosts Of Leptospira Species In The United States Virgin Islands, 2019–2020, Hannah M. Cranford, A. Springer Browne, Karen Lecount, Tammy Anderson, Camila Hamond, Linda Schlater, Tod Stuber, Valicia J. Burke-France, Marissa Taylor, Cosme J. Harrison, Katia Y. Matias, Alexandra Medley, John Rossow, Nicholas Wiese, Leanne Jankelunas, Leah De Wilde, Michelle Mehalick, Gerard L. Blanchard, Keith R. Garcia, Alan S. Mckinley, Claudia D. Lombard, Nicole F. Angeli, David Horner, Thomas Kelley, David J. Worthington, Jennifer Valiulis, Bethany Bradford, Are Berentsen, Johanna S. Salzer, Renee Galloway, Ilana J. Schafer, Kristine Bisgard, Joseph Roth, Brett R. Ellis, Esther M. Ellis, Jarlath E. Nally

USDA Wildlife Services: Staff Publications

During 2019–2020, the Virgin Islands Department of Health investigated potential animal reservoirs of Leptospira spp., the bacteria that cause leptospirosis. In this cross-sectional study, we investigated Leptospira spp. exposure and carriage in the small Indian mongoose (Urva auropunctata, syn: Herpestes auropunctatus), an invasive animal species. This study was conducted across the three main islands of the U.S. Virgin Islands (USVI), which are St. Croix, St. Thomas, and St. John. We used the microscopic agglutination test (MAT), fluorescent antibody test (FAT), real-time polymerase chain reaction (lipl32 rt-PCR), and bacterial culture to evaluate serum and kidney specimens and compared the …

Rooting Out Genetic Structure Of Invasive Wild Pigs In Texas, Anna M. Mangan, Antoinette J. Piaggio, Michael J. Bodenchuk, Courtney F. Pierce, Timothy J. Smyser

USDA Wildlife Services: Staff Publications

Invasive wild pigs (Sus scrofa), also called feral swine or wild hogs, are recognized as among the most destructive invasive species in the world. Throughout the United States, invasive wild pigs have expanded rapidly over the past 40 years with populations now established in 38 states. Of the estimated 6.9 million wild pigs distributed throughout the United States, Texas supports approximately 40% of the population and similarly bears disproportionate ecological and economic costs. Genetic analyses are an effective tool for understanding invasion pathways and tracking dispersal of invasive species such as wild pigs and have been used recently …

Relationships Among Toilet Sharing, Water Source Locations, And Handwashing Places Without Observed Soap: A Cross-Sectional Study Of The Richest Households In Bangladesh, Mazbahul G. Ahamad, Mark Burbach, Fahian Tanin

School of Natural Resources: Faculty Publications

Background: A high percentage of the richest households in Bangladesh lack soap at their handwashing places, a problem that is typically considered to be one of the poor. Objective: We investigated toilet sharing practices, locations of water sources, and relevant sociodemographic factors associated with the observed handwashing places that lack soap in the richest (ninth wealth decile) households in Bangladesh. Methods: We used data from the 2017-18 Bangladesh Demographic and Health (BDHS) Survey. Logistic regression technique was used to investigate how toilet sharing practices, water source locations, and different sociodemographic factors were associated with observed handwashing places without soap. Results: …

The Sandhill Crane State: A Naturalist’S Guide To Nebraska, Paul Johnsgard

Zea E-Books Collection

This book includes the locations, descriptions, and points of biological, historical, geological, or paleontological interest of nearly 350 sites in Nebraska, most of which are free to access. Its 53,000 words include accounts of 9 state historical parks, 8 state parks, 2 national forests, 2 national monuments, and 7 national wildlife refuges as well as 181 wildlife management areas, 56 waterfowl production areas, and 54 state recreation areas. It also includes 48 state and county maps, 18 drawings, 33 photographs, and nearly 200 literature citations.

doi: 10.32873/unl.dc.zea.1305

Water Current, Volume 53, No. 2, Fall 2021

Water Current Newsletter

Fall Harvest: Research, News and More from the Nebraska Water Center

Greenhouse Gas Emissions And Drought Projections For Nebraska, Adam Liska

Adam Liska Papers

This lecture will focus on three issues. The first is a presentation of data from the first greenhouse gas emissions inventory for the State of Nebraska, which will be published in the coming weeks. In 2016, emissions from beef cattle made up 23% of net state emissions, and coal for electricity made up 23.7% of net state emissions. The second issue to be addressed are the impacts of the 2012 drought on agriculture in Nebraska and the region. The drought of 2012 indicates that future droughts in the 21^st century in the region can be a dominant influence on …

Adaptation Of An Artificial Bait To An Automated Aerial Delivery System For Landscape-Scale Brown Treesnake Suppression, Rafael A. Garcia, Thomas W. Mcauliffe, Lorelie P. Bumanlag, Shane R. Siers, Bruce A. Kimball

USDA Wildlife Services: Staff Publications

Dead neonatal mice are currently used as bait for delivery of toxin to invasive brown treesnakes (Boiga irregularis) on Guam; once deployed in the field the mice are highly attractive to the snakes but only for about four days. An artificial bait containing a mixture of fats mimicking those in skin of the mice is also highly attractive to the snakes and remains attractive 2–3 times longer. The artificial bait, however, costs more than the mice, and is more difficult to attach to the capsules of a novel aerial bait delivery system. This paper describes a reformulation of the bait …

Threading The Needle: How Humans Influence Predator–Prey Spatiotemporal Interactions In A Multiple-Predator System, Asia Murphy, Duane R. Diefenbach, Mark Ternent, Matt Lovallo, David Miller

USDA Wildlife Services: Staff Publications

Perceived predation risk and the resulting antipredator behaviour varies across space, time and predator identity. Communities with multiple predators that interact and differ in their use of space, time of activity and hunting mode create a complex landscape for prey to avoid predation. Anthropogenic presence and disturbance have the potential to shift interactions among predators and prey and the where and when encounters occur. We examined how white-tailed deer Odocoileus virginianus fawn spatiotemporal antipredator behaviour differed along an anthropogenic disturbance gradient that had black bears Ursus americanus, coyotes Canis latrans, bobcats Lynx rufus and humans present. We quantified (a) spatial …

Variations, Validations, Degradations, And Noninvasive Determination Of Pregnancy Using Fecal Steroid Metabolites In Free-Ranging Pronghorn, Cole A. Bleke, Eric M. Gese, Susannah S. French

USDA Wildlife Services: Staff Publications

Pregnancy status is a key parameter used to assess reproductive performance of a species as it represents a starting point for measuring vital rates. Vital rates allow managers to determine trends in populations such as neonate survival and recruitment; two important factors in ungulate population growth rates. Techniques to determine pregnancy have generally involved capture and restraint of the animal to obtain blood samples for determining serum hormone levels. Non-invasive pregnancy assessment, via feces, eliminates any hazards between handler and animal, as well as removes handling-induced physiological biases. Using noninvasive fecal sampling, we conducted hormone validations, investigated pregnancy rates, and …