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Full-Text Articles in Physical Sciences and Mathematics

Rodents In Agriculture: A Broad Perspective, Gary Witmer Jan 2022

Rodents In Agriculture: A Broad Perspective, Gary Witmer

USDA Wildlife Services: Staff Publications

The largest taxonomic group of mammals is rodents, with over 2200 species known around the world [1]. More recently, it was stated that over 2500 species exist [2]. Many species exist on all continents, with the exception of Antarctica. Rodents have adapted to all ecosystems of the world, including tundra, alpine, temperate forests, grasslands, arid regions, and aquatic systems. They provide many ecosystem functions, including soil aeration and mixing, seed and spore dispersal, vegetation succession, and being an important food source for predatory animals. Some species of rodents are even consumed by people in some parts of the world. Most …


Evaluating The Effects Of Mountain Beaver (Aplodontia Rufa) Management On Conifer Stocking In Western Oregon, Jimmy D. Taylor, Vanessa M. Petro Jan 2021

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 …


Population Increases Of Large Birds In North America Pose Challenges For Aviation Safety, Richard A. Dolbeer Jan 2020

Population Increases Of Large Birds In North America Pose Challenges For Aviation Safety, Richard A. Dolbeer

USDA Wildlife Services: Staff Publications

There is a strong correlation between bird mass and the likelihood of aircraft damage during a bird–aircraft collision. Thus, the U.S. Federal Aviation Administration (FAA) has established airworthiness standards related to bird mass for engines, airframes, and windshields. Most standards use large (1.8 kg) and medium (1.1 kg) birds as benchmarks (the empennage and certain large turbofan engines use a 3.6-kg bird). There are 20 large (≥1.8 kg) and 16 medium (1.1–1.7 kg) bird species in North America with ≥20 strikes reported for civil aircraft (FAA National Wildlife Strike Database), 1990 to 2018. I analyzed the population changes of these …


The Changing Role Of Rodenticides And Their Alternatives In The Management Of Commensal Rodents, Gary Witmer Oct 2019

The Changing Role Of Rodenticides And Their Alternatives In The Management Of Commensal Rodents, Gary Witmer

USDA Wildlife Services: Staff Publications

Rodents cause substantial damage and losses of foodstuffs around the world. They also transmit many diseases to humans and livestock. While various methods are used to reduce damage caused by rodents, rodenticides remain an important tool in the toolbox. However, like all tools, rodenticides have advantages and disadvantages. Several considerations are shaping the future of rodenticide use, including manufacturing and registration costs, concern about toxicity levels and nontarget animal hazards, potential hazards to children, reduced effectiveness of some formulations, and humaneness to the targeted rodents. Many of these disadvantages apply to anticoagulant rodenticides, and their use is being more restricted …


Ecology And Management Of Rodents In No-Till Agriculture In Washington, Usa, Gary W. Witmer, Rodney Sayler, David Huggins, Jason Capelli Oct 2007

Ecology And Management Of Rodents In No-Till Agriculture In Washington, Usa, Gary W. Witmer, Rodney Sayler, David Huggins, Jason Capelli

USDA Wildlife Services: Staff Publications

No-till farming is an important approach to sustainable agriculture because it can conserve soil and water resources. Unfortunately, rodent populations can thrive under no-till conditions because burrow systems are not disrupted by annual plowing and plant residues build-up on the surface, providing cover and insulation. This can result in substantial crop damage. We assessed rodent populations, habitat use, food habits, and crop damage in a no-till cropping system in Washington, USA. We also conducted preliminary trials of methods to reduce rodent populations and crop damage. In the fall, many more rodents were captured in fields with unharvested crops than in …


Crop Diversification Leads To Diverse Bird Problems In Hawaiian Agriculture, Marni E. Koopman, William C. Pitt Sep 2007

Crop Diversification Leads To Diverse Bird Problems In Hawaiian Agriculture, Marni E. Koopman, William C. Pitt

USDA Wildlife Services: Staff Publications

Over the last 20 years, Hawaii’s agriculture has shifted from a focus on sugar cane (Saccharum officinarum) and pineapples (Ananas comosus) produced on large farms to a diverse array of products produced on a multitude of smaller farms. This dramatic shift in production, in addition to the introduction of many new avian species, has resulted in a concomitant change in the problems faced by agriculture. We surveyed farmers to determine the extent of bird damage to crops, the species responsible, the crops most vulnerable, and control methods employed. Bird problems varied by island, but cardinals ( …


Rodenticide Use In Rodent Management In The United States: An Overview, Gary W. Witmer, John D. Eisemann Jan 2007

Rodenticide Use In Rodent Management In The United States: An Overview, Gary W. Witmer, John D. Eisemann

USDA Wildlife Services: Staff Publications

Rodents occur worldwide and have adapted to most types of ecosystems. Rodents provide many important ecosystem functions and while most rodent species do not cause serious damage problems, a small number of species do. Rodent-caused damage includes crop and stored food consumption and contamination, forestry and nursery damage, rangeland damage, ornamental plant damage, property damage, cable and irrigation pipe damage, disease transmission, and, when introduced to islands, damage and even extinction of native flora and fauna. Many tools are used to reduce rodent populations and damage. Rodenticides are an especially important tool in rodent management. Many types of active ingredients …


A Simulation Model For Determining Cost-Effectiveness Of Fences For Reducing Deer Damage, Kurt C. Vercauteren, Michael J. Lavelle, Scott E. Hygnstrom Aug 2006

A Simulation Model For Determining Cost-Effectiveness Of Fences For Reducing Deer Damage, Kurt C. Vercauteren, Michael J. Lavelle, Scott E. Hygnstrom

USDA Wildlife Services: Staff Publications

The installation of fences to protect agricultural products, natural resources, or other areas from deer (Odocoileus spp.) can be expensive and potential benefits of fencing are difficult to quantify. A rational method is needed to help evaluate whether fencing can be cost-effective and which fence designs will be optimal for particular applications. We describe an interactive, dynamic simulation model that conducts economic analyses and predicts economic benefit associated with fences for crops relative to area and perimeter of protected plot, value of crop, percentage of crop damaged by deer annually prior to fencing, efficacy of fence, and costs of fence …


Height Distribution Of Birds Recorded By Collisions With Civil Aircraft, Richard A. Dolbeer Feb 2006

Height Distribution Of Birds Recorded By Collisions With Civil Aircraft, Richard A. Dolbeer

USDA Wildlife Services: Staff Publications

The National Wildlife Strike Database for Civil Aviation in the United States contained 38,961 reports of aircraft collisions with birds (bird strikes) from 1990–2004 in which the report indicated the height above ground level (AGL). I analyzed these strike reports to determine the distribution of all strikes and those strikes causing substantial damage to aircraft by height. For the 26% of strikes above 500 feet (152 m) AGL (n=10,143), a simple negative exponential model, with height as the independent variable, explained 99% of the variation in number of bird strikes per 1,000-foot (305-m) interval. Strikes declined consistently by 32% every …


The Effects Of Lactation On Seedling Damage By Mountain Beaver, Wendy M. Arjo, Dale L. Nolte, Julie L. Harper, Bruce A. Kimball Jun 2004

The Effects Of Lactation On Seedling Damage By Mountain Beaver, Wendy M. Arjo, Dale L. Nolte, Julie L. Harper, Bruce A. Kimball

USDA Wildlife Services: Staff Publications

The mountain beaver is a semi-fossorial rodent of the Pacific Northwest and is among a variety of herbivores that retard plant growth and cause tree seedling deformities and mortality. Douglas-61 seedlings are planted in the Pacific Northwest from February through March, a period coinciding with mountain beaver parturition. Previous research suggested that in spring, lactating females depend more on conifers than do non-lactating females and males. We conducted experiments to determine if female reproductive condition influenced seedling damage, and if physiological stage of the seedling affected damage. Dormant and flushing trees were offered to 6 pregnant and 6 non-pregnant females …


Nontarget Bird Use Of Drc-1339 Bait Sites During Operational Baiting Programs In Louisiana And Texas, Patricia A. Pipas, John L. Cummings, John D. Eisemann, Richard M. Engeman Nov 2003

Nontarget Bird Use Of Drc-1339 Bait Sites During Operational Baiting Programs In Louisiana And Texas, Patricia A. Pipas, John L. Cummings, John D. Eisemann, Richard M. Engeman

USDA Wildlife Services: Staff Publications

Nontarget bird use of DRC-1339 bait sites was assessed during operational baiting programs from 2000-2002 in Louisiana and from 2001-2002 in Texas. DRC-1339 is an avicide registered with the U.S. Environmental Protection Agency to manage blackbirds causing damage to agriculture. It was used in Louisiana between 15 February to 15 March and in Texas from January though March to protect newly planted rice. In Louisiana, there were 55 bait sites observed during 316 observation periods (158 observation hours) and 312 flush-counts conducted from 2000-2002. In Texas, there were 26 bait sites observed during 182 observation periods (91 observation hours) and …


Development Of A Synthetic Materials Mimic For Vulture Olfaction Research, Richard E. Mauldin, Bruce A. Kimball, John J. Johnston, Jerome C. Hurley, Michael L. Avery Jan 2003

Development Of A Synthetic Materials Mimic For Vulture Olfaction Research, Richard E. Mauldin, Bruce A. Kimball, John J. Johnston, Jerome C. Hurley, Michael L. Avery

USDA Wildlife Services: Staff Publications

Since the early 1990's, an increase in damage associated with the activities of black (Coragyps atratus) and turkey (Cathartes aura) vultures has been observed. These activities include extensive damage to real and personal property. Vultures display an affinity for objects made of synthetic materials such as vinyl or plastic, and frequently damage items such as seat cushions, roof shingles, and caulking sealant. To explore whether this behavior in vultures is olfactorily driven, volatile compounds emitted by 21 vulture-damaged objects were collected and analyzed using purge-and-trap gas chromatography/mass spectrometry. Results from these analyses were tabulated and the …


Dealing With Nuisance And Depredating Black Bears, Gary W. Witmer, Donald G. Whittaker Feb 2001

Dealing With Nuisance And Depredating Black Bears, Gary W. Witmer, Donald G. Whittaker

USDA Wildlife Services: Staff Publications

Black bears (Ursus americanus) are a valued resource in North America but pose many challenges to resource managers. They may be managed in 1 or more ways, including sustained yield harvests, nuisance animal control, or conservation management. Many black bear populations are stable or increasing, and combine with expanding human populations, increased development, and recreational activities, are leading to an increase in human-bear conflicts. Historically, methods such as relocation, general hunting seasons, or special hunts have been used in an effort to reduce bear density and damage, or to target individual offending animals. Many resource managers now operate …