Population Biology Commons^™

Variation In Angiostrongylus Cantonensis Infection In Definitive And Intermediate Hosts In Hawaii, A Global Hotspot Of Rat Lungworm Disease, Chris Niebuhr, Shane R. Siers, Israel Leinbach, Lisa M. Kaluna, Susan I. Jarvi

USDA Wildlife Services: Staff Publications

Angiostrongylus cantonensis (rat lungworm) is a tropical and subtropical parasitic nematode, with infections in humans causing angiostrongyliasis (rat lungworm disease), characterized by eosinophilic meningitis. Hawaii has been identified as a global hotspot of infection, with recent reports of high infection rates in humans, as well as rat definitive and snail intermediate hosts. This study investigated variation in A. cantonensis infection, both prevalence and intensity, in wild populations of two species of rats (Rattus exulans and R. rattus) and one species of snail (Parmarion martensi). An overall infection prevalence of 86.2% was observed in P. martensi and …

Understanding Tolerance For An Invasive Species: An Investigation Of Hunter Acceptance Capacity For Wild Pigs (Sus Scrofa) In Texas, Hailey E. Mclean, Tara L. Teel, Alan Bright, Lauren M. Jaebker, John M. Tomecek, Maureen G. Frank, Rachael L. Connally, Stephanie A. Shwiff, Keith M. Carlisle

USDA Wildlife Services: Staff Publications

Invasive species and their establishment in new areas have significant impacts on the ecological, economic, and social well-being of our planet. Wild pigs (Sus scrofa) are one of the world’s most formidable invasive species, particularly in the United States. They cause significant damage to agriculture and ecosystems, and can transmit diseases to livestock, wildlife, and people. There is an inherent social dimension to the issue of wild pigs due in part to the fact that people hunt them. Hunting contributes to both the control and spread of this species. The objectives of this study were to: 1) determine hunters’ overall …

A Framework To Evaluate Whether To Pool Or Separate Behaviors In A Multilayer Network, Annemarie Van Der Marel, Sanjay Prasher, Chelsea Carminito, Claire L. O'Connell, Alexa Phillips, Bryan M. Kluever, Elizabeth A. Hobson

USDA Wildlife Services: Staff Publications

A multilayer network approach combines different network layers, which are connected by interlayer edges, to create a single mathematical object. These networks can contain a variety of information types and represent different aspects of a system. However, the process for selecting which information to include is not always straightforward. Using data on 2 agonistic behaviors in a captive population of monk parakeets (Myiopsitta monachus), we developed a framework for investigating how pooling or splitting behaviors at the scale of dyadic relationships (between 2 individuals) affects individual- and group-level social properties. We designed 2 reference models to test whether randomizing the …

Improved Strategies For Handling Entire Sounders Of Wild Pigs, Michael Lavelle, Nathan P. Snow, Christine K. Ellis, Joe M. Halseth, Justin W. Fischer, Michael P. Glow, Eric H. Vannatta, Bethany A. Friesenhahn, Kurt C. Vercauteren

USDA Wildlife Services: Staff Publications

As wild pigs (Sus scrofa) expand throughout North America researchers are increasingly being tasked with trapping and marking entire sounders (family groups) to attach monitoring devices or other identifying markers to gather knowledge to inform management. Capture and marking procedures can be challenging, dangerous for both researchers and animals, and time consuming, particularly when handling sounders. We developed an integrated pig‐handling system to efficiently sort, weigh, chemically immobilize, and mark multiple wild pigs simultaneously in a controlled manner. To assess the functionality of the system, we evaluated 18 capture events in Texas, USA, from January 2018 to March …

Detection Of Two Dissimilar Chronic Wasting Disease Isolates In Two Captive Rocky Mountain Elk (Cervus Canadensis) Herds: Two Distinctive Chronic Wasting Disease Isolates Identified In Captive Elk, Tracy A. Nichols, Eric M. Nicholson, Yihui Liu, Wanyin Tao, Terry R. Spraker, Michael Lavelle, Justin W. Fischer, Qingzhong Kong, Kurt C. Vercauteren

USDA Wildlife Services: Staff Publications

Chronic wasting disease (CWD) continues to spread in both wild and captive cervid herds in North America and has now been identified in wild reindeer and moose in Norway, Finland and Sweden. There is limited knowledge about the variety and characteristics of isolates or strains of CWD that exist in the landscape and their implications on wild and captive cervid herds. In this study, we evaluated brain samples from two captive elk herds that had differing prevalence, history and timelines of CWD incidence. Site 1 had a 16-year history of CWD with a consistently low prevalence between 5% and 10%. …

Increased Abundance Of The Common Raven Within The Ranges Of Greater And Gunnison Sage-Grouse: Influence Of Anthropogenic Subsidies And Fire, Jonathan B. Dinkins, Lindsey R. Perry, Jeffrey L. Beck, Jimmy D. Taylor

USDA Wildlife Services: Staff Publications

The common raven (Corvus corax; raven) is native to North America and has increased in abundance, especially throughout western North America, during the last century. Human subsidies have facilitated raven dispersal into less suitable habitats and enabled these populations to maintain higher annual survival and reproduction. Concomitantly, overabundant raven populations are impacting other native at-risk species such as the greater sage-grouse (Centrocercus urophasianus) and potentially the Gunnison sage-grouse (C. minimus). Using Breeding Bird Survey data from 1995–2014, we evaluated raven count data to quantitatively describe changes in abundance and expansion into sagebrush ( …

Inefficiency Of Anthraquinone-Based Avian Repellents When Applied To Sunflower: The Importance Of Crop Vegetative And Floral Characteristics In Field Applications, Brandon Kaiser, Burton L. Johnson, Mike Ostlie, Scott J. Werner, Page E. Klug

USDA Wildlife Services: Staff Publications

BACKGROUND: Blackbirds (Icteridae) cause significant damage to sunflower (Helianthus annuus L.) prompting the need for effective management tools. Anthraquinone-based repellents can reduce feeding by > 80% in laboratory settings, but require birds to learn the negative association through repellent ingestion. We evaluated an anthraquinone-based repellent applied directly to mature sunflower plants for its ability to reduce bird damage. We used captive male red-winged blackbirds (Agelaius phoeniceus) to evaluate efficacy of two anthraquinone-based formulations in varying concentrations and applied in a manner attainable by sunflower producers. We also assessed field application methods for repellent coverage and anthraquinone residues when …

Distribution And Abundance Of Scaup Using Baitfish And Sportfish Farms In Eastern Arkansas, Stephen A. Clements, Brian S. Dorr, Brian Davis, Luke A. Roy, Carole R. Engle, Katie C. Hanson-Dorr, Anita M. Kelly

USDA Wildlife Services: Staff Publications

Arkansas' bait- and sportfish facilities are commonly used by various piscivorous bird species, including lesser scaup (Aythya affinis) and greater scaup (A. marila) that consume substantial quantities of fish. To mediate this predation, farmers implement extensive bird harassment programs that create additional costs to fish loss, thus research investigating the distribution and abundance of scaup is needed to help farmers allocate their bird harassment efforts more efficiently. In winters 2016–2017 and 2017–2018 we conducted 1,368 pond surveys to investigate pond use by scaup on farms during birds' regular wintering period (i.e., November–March). We used intrinsic and …

Surgical Sterilization Impacts On Behavior Of Coyote Pairs, Tyler Leary, Jeffrey T. Schultz, Julie K. Young

USDA Wildlife Services: Staff Publications

Coyotes (Canis latrans) involved in depredation of livestock, an act frequently resulting in human-wildlife conflict, often do so out of necessity for provisioning pups. Surgical sterilization methods such as vasectomy that preserve gonadal hormones have been successful in reducing depredation by free-ranging coyotes while allowing individuals to maintain territoriality and mate fidelity. However, use of these methods remain costly and ineffective for wide-scale use. Given the alternative proposal of using chemical sterilization techniques, we investigated whether the use of hormone-altering sterilization methods impacted behavior of captive coyote pairs (i.e., male-female pair bonds). Our objective was to evaluate behavior …

Population Genomic Transformations Induced By Isolation Of Wild Bird Avian Influenza Viruses (Orthomyxoviridae) In Embryonated Chicken Eggs, Matthew W. Hopken, Antoinette J. Piaggio, K. L. Pabilonia, James Pierce, Theodore Anderson, Courtney Pierce, Zaid Abdo

USDA Wildlife Services: Staff Publications

Isolation and cultivation of wild-type viruses in model organism cells or tissues is standard practice in virology. Oftentimes, the virus host species is distantly related to the species from which the culture system was developed. Thus, virus culture in these tissues and cells basically constitutes a host jump, which can lead to genomic changes through genetic drift and/or adaptation to the culture system. We directly sequenced 70 avian influenza virus (Orthomyxoviridae) genomes from oropharyngeal/cloacal swabs collected from wild bird species and paired virus isolates propagated from the same samples following isolation in specific-pathogen-free embryonated chicken eggs. The data were analyzed …

Temporal And Spatial Blood Feeding Patterns Of Urban Mosquitoes In The San Juan Metropolitan Area, Puerto Rico, Matthew W. Hopken, Limarie J. Reyes-Torres, Nicole Scavo, Antoinette J. Piaggio, Zaid Abdo, Daniel Taylor, James Pierce, Donald A. Yee

USDA Wildlife Services: Staff Publications

Simple Summary: Understanding the biodiversity of urban ecosystems is critical for management of invasive and pest species, conserving native species, and disease control. Mosquitoes (Culicidae) are ubiquitous and abundant in urban ecosystems, and rely on blood meals taken from vertebrates. We used DNA from freshly blood-fed mosquitoes to characterize the diversity of vertebrate host species in the San Juan Metropolitan Area, Puerto Rico. We collected two mosquito species that fed on a variety of vertebrates. Culex quinquefasciatus fed on 17 avian taxa (81.2% of blood meals), seven mammalian taxa (17.9%), and one reptilian taxon (0.85%). Aedes aegypti blood meals were …

Evaluating The Effects Of Mountain Beaver (Aplodontia Rufa) Management On Conifer Stocking In Western Oregon, Jimmy D. Taylor, Vanessa M. Petro

USDA Wildlife Services: Staff Publications

Mountain beaver (Aplodontia rufa) is the most primitive rodent species in North America and is endemic to the Pacific Northwest, USA. Within their range, mountain beaver cause more conflict with conifer forest regeneration than any other vertebrate species. Most damage occurs as a result of clipping and browsing new seedlings, which reduces stocking density and delays stand development. An integrated approach using trapping and a registered toxicant (baiting) has been suggested as the most efficacious means to reduce seedling loss during stand initiation. We evaluated this management strategy in intensively managed conifer stands across two mountain ranges in …

Modeling Mongoose Rabies In The Caribbean: A Model-Guided Fieldwork Approach To Identify Research Priorities, Caroline C. Sauvé, Erin E. Rees, Amy T. Gilbert, Are R. Berentsen, Agathe Allibert, Patrick A. Leighton

USDA Wildlife Services: Staff Publications

We applied the model-guided fieldwork framework to the Caribbean mongoose rabies system by parametrizing a spatially-explicit, individual-based model, and by performing an uncertainty analysis designed to identify parameters for which additional empirical data are most needed. Our analysis revealed important variation in output variables characterizing rabies dynamics, namely rabies persistence, exposure level, spatiotemporal distribution, and prevalence. Among epidemiological parameters, rabies transmission rate was the most influential, followed by rabies mortality and location, and size of the initial infection. The most influential landscape parameters included habitat-specific carrying capacities, landscape heterogeneity, and the level of resistance to dispersal associated with topography. Movement …

Avian Influenza A Viruses Reassort And Diversify Differently In Mallards And Mammals, Ketaki Ganti, Anish Bagga, Juliana Dasilva, Samuel S. Shepard, John R. Barnes, Susan A. Shriner, Katia Koelle, Anice C. Lowen

USDA Wildlife Services: Staff Publications

Reassortment among co-infecting influenza A viruses (IAVs) is an important source of viral diversity and can facilitate expansion into novel host species. Indeed, reassortment played a key role in the evolution of the last three pandemic IAVs. Observed patterns of reassortment within a coinfected host are likely to be shaped by several factors, including viral load, the extent of viral mixing within the host and the stringency of selection. These factors in turn are expected to vary among the diverse host species that IAV infects. To investigate host differences in IAV reassortment, here we examined reassortment of two distinct avian …

Impacts Of A Large Invasive Mammal On Water Quality In Riparian Ecosystems, Sara Bolds, B. Graeme Lockaby, Stephen S. Ditchkoff, Mark D. Smith, Kurt C. Vercauteren

USDA Wildlife Services: Staff Publications

Wild pigs (Sus scrofa) are a highly invasive species in many regions of the world and can act as ecosystem engineers in areas where they are established. In riparian ecosystems, wild pigs may affect water quality parameters and introduce fecal bacteria, although previous studies have reported conflicting results. We propose four conditions that we believe are needed for an accurate assessment of wild pig impacts on water quality and address each one in our study. Water samples were collected between May 2018 and June 2019 in riparian watersheds on a privately owned property in Alabama that was densely populated by …

Modelling The Factors Affecting The Probability For Local Rabies Elimination By Strategic Control, Johann L. Kotzé, John Duncan Grewar, Aaron M. Anderson

USDA Wildlife Services: Staff Publications

Dog rabies has been recognized from ancient times and remains widespread across the developing world with an estimated 59,000 people dying annually from the disease. In 2011 a tri-partite alliance consisting of the OIE, the WHO and the FAO committed to globally eliminating dog-mediated human rabies by 2030. Regardless of global support, the responsibility remains with local program managers to implement successful elimination programs. It is well known that vaccination programs have a high probability of successful elimination if they achieve a population-coverage of 70%. It is often quoted that reducing population turnover (typically through sterilizations) raises the probability for …

Best Management Practices For Trapping Furbearers In The United States, H. Bryant White, Gordon R. Batcheller, Edward K. Boggess, Clifford L. Brown, Joseph W. Butfiloski, Thomas A. Decker, John D. Erb, Michael W. Fall, David A. Hamilton, Tim L. Hiller, George F. Hubert Jr., Matthew J. Lovallo, John F. Olson, Nathan M. Roberts

USDA Wildlife Services: Staff Publications

Humans have used wild furbearers for various purposes for thousands of years. Today, furbearers are sustainably used by the public for their pelts, leather, bones, glands, meat, or other purposes. In North America, contemporary harvest of furbearers has evolved along with trap technologies and societal concerns, and is now highly regulated and more closely coupled with harvest analysis and population monitoring. Traps and regulated trapping programs provide personal or cultural rewards that can also support conservation, and can assist with advancing ecological knowledge through research, protecting endangered species, restoring populations or habitats, protecting personal property, and enhancing public health and …

A Sonic Net Reduces Damage To Sunflower By Blackbirds (Icteridae): Implications For Broad-Scale Agriculture And Crop Establishment, Amanda K. Werrell, Page E. Klug, Romuald N. Lipcius, John P. Swaddle

USDA Wildlife Services: Staff Publications

Blackbirds, such as red-winged blackbirds (Agelaius phoeniceus), are notorious agricultural pests and damage crops at multiple stages of growth. Our aim was to test a novel deterrent, the use of sound designed to mask communication among birds (termed a “Sonic Net”), to deter blackbirds (Icteridae) from target areas of maturing sunflower crops. The Sonic Net masks communication of a target species by delivering “pink noise” that overlaps with the frequencies that the species uses for acoustic communication. If birds cannot hear predators or conspecific warning calls their perceived predation risk increases, and they relocate to an area with …

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 …

Evaluation Of A Warfarin Bait For Controlling Invasive Wild Pigs (Sus Scrofa), James C. Beasley, Lindsay M. Clontz, Allison Rakowski, Nathan P. Snow, Kurt C. Vercauteren

USDA Wildlife Services: Staff Publications

BACKGROUND: Wild pigs (Sus scrofa) cause widespread environmental and economic damage, and as a result are subjected to extensive control. Current management strategies have proven insufficient, and there is growing interest in use of toxicants to control invasive populations of this species. In 2017 a low-dose warfarin bait was federally approved for use in controlling wild pigs in the United States. However, no states have allowed use of this bait due to unanswered questions regarding welfare concerns, field efficacy, and non-target impacts.

RESULTS: All captive wild pigs fed 0.005% warfarin baits in no choice feeding trials succumbed in an average …