Scott E. Hygnstrom

Publications of Scott E. Hygnstrom

• Resource selection by elk in an agro-forested landscape of northwestern Nebraska.

  Authors: David M Baasch, Justin W Fischer, Scott E Hygnstrom, Kurt C VerCauteren, Andrew J Tyre, Joshua J Millspaugh, James W Merchant, Jerry D Volesky

  Environmental management. 11/2010; 46(5):725-37.

  In recent years, elk have begun recolonizing areas east of the Rocky Mountains that are largely agro-forested ecosystems composed of privately owned land where management of elk is an increasingIn recent years, elk have begun recolonizing areas east of the Rocky Mountains that are largely agro-forested ecosystems composed of privately owned land where management of elk is an increasing concern due to crop and forage depredation and interspecific disease transmission. We used a Geographic Information System, elk use locations (n = 5013), random locations (n = 25,065), discrete-choice models, and information-theoretic methods to test hypotheses about elk resource selection in an agro-forested landscape located in the Pine Ridge region of northwestern Nebraska, USA. Our objectives were to determine landscape characteristics selected by female elk and identify publicly owned land within the Pine Ridge for potential redistribution of elk. We found distance to edge of cover influenced selection of resources by female elk most and that in areas with light hunting pressure, such as ours, this selection was not driven by an avoidance of roads. Female elk selected resources positioned near ponderosa pine cover types during all seasons, exhibited a slight avoidance of roads during spring and fall, selected areas with increased slope during winter and spring, and selected north- and east-facing aspects over flat areas and areas with south-facing slopes during winter months. We used our models to identified a potential elk redistribution area that had a higher proportion of landcover with characteristics selected by elk in our study area than the current herd areas and more landcover that was publicly owned. With appropriate management plans, we believe elk within the Potential Elk Redistribution Area would predominantly occupy publicly owned land, which would help minimize crop and forage damage on privately owned lands.

• First record of pseudorabies in feral Swine in nebraska.

  Authors: Sam Wilson, Alan R Doster, Justin D Hoffman, Scott E Hygnstrom

  Journal of wildlife diseases. 08/2009; 45(3):874-6.

  In 2007, two new populations of feral swine were discovered in Nance and Valley counties, Nebraska, USA. Necropsies and serologic testing was done on two individuals from the Nance County herd.In 2007, two new populations of feral swine were discovered in Nance and Valley counties, Nebraska, USA. Necropsies and serologic testing was done on two individuals from the Nance County herd. Results indicated that a lactating sow had positive antibodies for pseudorabies virus (PRV). Investigations conducted by Nebraska Game and Parks Commission Law Enforcement division confirmed that the infected individual was transported illegally to Nebraska, USA, from Texas, USA. All domestic swine herds located within an 8 km radius of the infected individual tested negative for antibodies to PRV. Our results provide a clear example of how diseases can spread because of anthropogenic activities and highlight the need for disease surveillance and monitoring in the import of invasive species.

• Prevalence and serovars of Salmonella in the feces of free-ranging white-tailed deer (Odocoileus virginianus) in Nebraska.

  Authors: David G Renter, David P Gnad, Jan M Sargeant, Scott E Hygnstrom

  Journal of wildlife diseases. 08/2006; 42(3):699-703.

  To determine the prevalence and serovars of Salmonella in free-ranging deer, we cultured feces from white-tailed deer (Odocoileus virginianus) harvested by hunters during a regular firearm season inTo determine the prevalence and serovars of Salmonella in free-ranging deer, we cultured feces from white-tailed deer (Odocoileus virginianus) harvested by hunters during a regular firearm season in southeastern Nebraska (USA). We recovered Salmonella from 5 (1%; 95% confidence interval: 0.37-2.20%) of 500 samples and identified four different Salmonella enterica serovars [Litchfield (1), Dessau (1), Infantis (2), and Enteritidis (1)]. Although the prevalence of Salmonella in free-ranging deer appears to be low, the serovars recovered are known to be pathogenic to humans and animals.

• Efficacy of in-furrow zinc phosphide pellets for controlling rodent damage in no-till corn

  Authors: Scott E Hygnstrom, Kurt C VerCauteren, Ron A Hines, Charles W Mansfield

  International Biodeterioration & Biodegradation.

  Plagues of rodents in field crops have been a problem of human societies for centuries. These problems diminished with the onset of effective herbicides and clean farming practices in the 1960s, butPlagues of rodents in field crops have been a problem of human societies for centuries. These problems diminished with the onset of effective herbicides and clean farming practices in the 1960s, but there has been a resurgence of rodent irruptions in cropfields since the advent of conservation tillage systems. We examined the efficacy of in-furrow applications of 2% zinc phosphide (Zn3P2) pellets (27.5 kg ha−1 [5 lb acre−1]) at planting for the control of rodent damage in no-till corn. Three independent field studies were conducted in northeastern NE, southern IL, and southern IN. Vole populations in the most severely damaged fields (IL) ranged from 104 to 138 active colonies ha−1. Zn3P2 reduced yield loss in the three study areas by 7–34%. Projected economic returns ranged from US$1044 to US$5360, based on representative 64-ha fields and a net profit of US$250 ha−1. Benefit:cost ratios ranged from 1.1 to 5.6:1 and were directly related to vole population levels. To prevent rodent damage in no-till cornfields, we recommend an integrated pest management approach that incorporates the use of a combination of the following techniques: rodent population monitoring, economic thresholds, mowing, early pre-plant herbicides, broadcast whole-kernel corn, and in-furrow applications of Zn3P2 pellets.

• Crop, Native Vegetation, and Biofuels: Response of White-Tailed Deer to Changing Management Priorities.

  Authors: W. David Walter, Kurt C. VerCauteren, Jason M. Gilsdorf, Scott E. Hygnstrom

  The expansion of the cellulosic biofuels industry throughout the United States has broad-scale implications for wildlife management on public and private lands. Knowledge is limited on the effects ofThe expansion of the cellulosic biofuels industry throughout the United States has broad-scale implications for wildlife management on public and private lands. Knowledge is limited on the effects of reverting agriculture to native grass, and vice versa, on size of home range and habitat use of white-tailed deer (Odocoileus virginianus). We followed 68 radiocollared female deer from 1991 through 2004 that were residents of DeSoto National Wildlife Refuge (DNWR) in eastern Nebraska, USA. The refuge was undergoing conversion of vegetation out of row-crop agriculture and into native grass, forest, and emergent aquatic vegetation. Habitat in DNWR consisted of 30% crop in 1991 but removing crops to establish native grass and wetland habitat at DNWR resulted in a 44% reduction in crops by 2004. A decrease in the amount of crops on DNWR contributed to a decline in mean size of annual home range from 400 ha in 1991 to 200 ha in 2005 but percentage of crops in home ranges increased from 21% to 29%. Mean overlap for individuals was 77% between consecutive annual home ranges across 8 years, regardless of crop availability. Conversion of crop to native habitat will not likely result in home range abandonment but may impact disease transmission by increasing rates of contact between deer social groups that occupy adjacent areas. Future research on condition indices or changes in population parameters (e.g., recruitment) could be incorporated into the study design to assess impacts of habitat conversion for biofuel production.

• Propane exploders and electronic guards were ineffective at reducing deer damage in cornfields.

  Authors: Jason M. Gilsdorf, Scott E. Hygnstrom, Kurt C. VerCauteren, Erin E. Blankenship, Richard M. Engeman

  White-tailed deer (Odocoileus virginianus) cause millions of dollars of damage to agricultural crops annually. We tested the effectiveness of propane exploders and Electronic Guards (Pocatello SupplyWhite-tailed deer (Odocoileus virginianus) cause millions of dollars of damage to agricultural crops annually. We tested the effectiveness of propane exploders and Electronic Guards (Pocatello Supply Depot, Pocatello, Id.) for reducing deer damage in cornfields during the silking-tasseling stage of growth. Track-count indices (F2,7=0.70, P=0.532), corn yields (F2,6=0.14, P=0.873), and estimated damage levels (F2,12=1.45 P=0.272) did not differ between experimental and control fields. The size (F2,11=0.08, P=0.924), location (F2,9 =0.30, P =0.750), and percent overlap (F2,9 =0.46, P =0.644) of use-areas of radiomarked female deer in the vicinity of experimental fields did not differ among before, during, and after 18-day treatment periods. In a related study, we placed propane exploders in cornfields within use-areas of 12 radiomarked female deer. The deer did not react appreciably to the devices: the size (F2,17=0.08, P=0.921), location (F2,22=1.37, P = 0.275), and percent overlap (F2,10 = 0.47, P = 0.636) of deer use-areas did not differ among before, during, and after 14-day treatment periods. We conclude that propane exploders and Electronic Guards have limited potential for reducing deer damage to corn at the silking-tasseling stage.

• Probabilistic movement model with emigration simulates movements of deer in Nebraska, 1990-2006.

  Authors: Charles J. Frost, Scott E. Hygnstrom, Andrew J. Tyre, Kent M. Eskridge, David M. Baasch, Justin R. Boner, Gregory M. Clements, Jason M. Gilsdorf, Travis C. Kinsell, Kurt C. VerCauteren

  Movements of deer can affect population dynamics, spatial redistribution, and transmission and spread of diseases. Our goal was to model the movement of deer in Nebraska in an attempt to predict theMovements of deer can affect population dynamics, spatial redistribution, and transmission and spread of diseases. Our goal was to model the movement of deer in Nebraska in an attempt to predict the potential for spread of chronic wasting disease (CWD) into eastern Nebraska. We collared and radio-tracked >600 white-tailed deer (Odocoileus virginianus) and mule deer (Odocoileus hemionus) in Nebraska during 1990-2006. We observed large displacements (>10 km) for both species and sexes of deer, including migrations up to 100 km and dispersals up to 50 km. Average distance traveled between successive daily locations was 166 m for male and 173 for female deer in eastern Nebraska, and 427 m for male and 459 for female deer in western Nebraska. Average daily displacement from initial capture point was 10 m for male and 14 m for female deer in eastern Nebraska, and 27 m for male and 28 m for female deer in western Nebraska. We used these data on naturally occurring movements to create and test 6 individual-based models of movement for white-tailed deer and mule deer in Nebraska, including models that incorporated sampling from empirical distributions of movement lengths and turn angles (DIST), correlated random walks (CRW), home point fidelity (FOCUS), shifting home point (SHIFT), probabilistic movement acceptance (MOVE), and probabilistic movement with emigration (MOVEwEMI). We created models in sequence in an attempt to account for the shortcomings of the previous model(s). We used the Kolmogrov-Smirnov goodness-of-fit test to verify improvement of simulated annual displacement distributions to empirical displacement distributions. The best-fit model (D = 0.07 and 0.08 for eastern and western Nebraska, respectively) included a probabilistic movement chance with emigration (MOVEwEMI) and resulted in an optimal daily movement length of 350 m (maximum daily movement length of 2800 m for emigrators) for eastern Nebraska and 370 m (maximum of 2960 m) for western Nebraska. The proportion of deer that moved as emigrators was 0.10 and 0.13 for eastern and western Nebraska, respectively. We propose that the observed spread of CWD may be driven by large movements of a small proportion of deer that help to establish a low prevalence of the disease in areas east of the current endemic area. Our movement models will be used in a larger individual-based simulation of movement, survival, and transmission of CWD to help determine future surveillance and management actions.

• An evaluation of three statistical methods used to model resource selection.

  Authors: David M. Baasch, Andrew J. Tyre, Joshua J. Millspaugh, Scott E. Hygnstrom, Kurt C. VerCauteren

  The performance of statistical methods for modeling resource selection by animals is difficult to evaluate with field data because true selection patterns are unknown. Simulated data based on a knownThe performance of statistical methods for modeling resource selection by animals is difficult to evaluate with field data because true selection patterns are unknown. Simulated data based on a known probability distribution, though, can be used to evaluate statistical methods. Models should estimate true selection patterns if they are to be useful in analyzing and interpreting field data. We used simulation techniques to evaluate the effectiveness of three statistical methods used in modeling resource selection. We generated 25 use locations per animal and included 10, 20, 40, or 80 animals in samples of use locations. To simulate species of different mobility, we generated use locations at four levels according to a known probability distribution across DeSoto National Wildlife Refuge (DNWR) in eastern Nebraska and western Iowa, USA. We either generated 5 random locations per use location or 10,000 random locations (total) within 4 predetermined areas around use locations to determine how the definition of availability and the number of random locations affected results. We analyzed simulated data using discrete choice, logistic-regression, and a maximum entropy method (Maxent). We used a simple linear regression of estimated and known probability distributions and area under receiver operating characteristic curves (AUC) to evaluate the performance of each method. Each statistical method was affected differently by number of animals and random locations used in analyses, level at which selection of resources occurred, and area considered available. Discrete-choice modeling resulted in precise and accurate estimates of the true probability distribution when the area in which use locations were generated was > or = the area defined to be available. Logistic-regression models were unbiased and precise when the area in which use locations were generated and the area defined to be available were the same size; the fit of these models improved with increased numbers of random locations. Maxent resulted in unbiased and precise estimates of the known probability distribution when the area in which use locations were generated was small (home-range level) and the area defined to be available was large (study area). Based on AUC analyses, all models estimated the selection distribution better than random chance. Results from AUC analyses, however, often contradicted results of the linear regression method used to evaluate model performance. Discrete-choice modeling was best able to estimate the known selection distribution in our study area regardless of sample size or number of random locations used in the analyses, but we recommend further studies using simulated data over different landscapes and different resource metrics to confirm our results. Our study offers an approach and guidance for others interested in assessing the utility of techniques for modeling resource selection in their study area.

• Evaluation of a deer-activated bioacoustic frightening device for reducing deer damage in cornfields.

  Authors: Jason M. Gilsdorf, Scott E. Hygnstrom, Kurt C. VerCauteren, Greg M. Clements, Erin E. Blankenship, Richard M. Engeman

  Deer (Odocoileus spp.) can cause substantial damage to agricultural crops, resulting in economic losses for producers. We developed a deer-activated bio-acoustic frightening device to reduceDeer (Odocoileus spp.) can cause substantial damage to agricultural crops, resulting in economic losses for producers. We developed a deer-activated bio-acoustic frightening device to reduce white-tailed deer (O. virginianus) damage in agricultural fields. The device consisted of an infrared detection system that activated an audio component which broadcast recorded distress and alarm calls of deer. We tested the device against unprotected controls in cornfields during the silking-tasseling stage of growth in July 2001. The device was not effective in reducing damage: track-count indices (F1,4=0.02, P=0.892), corn yield (F1,9=1.27, P=0.289), and estimated damage levels (F1,10=0.87, P=0.374) did not differ between experimental and control fields. The size (F2,26=1.00, P=0.380), location (F2,25 =0.39, P =0.684), and percent overlap (F2,25 =0.20, P =0.818) of use-areas of radiomarked female deer did not differ between during- and after-treatment periods. We concluded that the deer-activated bio-acoustic device was not effective in protecting cornfields in this study; however, the device may be more effective in small areas such as gardens or for high-value crops that do not grow tall enough to offer protective cover.

• An Integrated Vehicle-Mounted Telemetry System for VHF Telemetry Applications.

  Authors: Jason M. Gilsdorf, Kurt C. VerCauteren, Scott E. Hygnstrom, W. David Walter, Justin R. Boner, Greg M. Clements

• White-tailed Deer Browsing and Rubbing Preferences for Trees and Shrubs That Produce Nontimber Forest Products.

  Authors: Scott E. Hygnstrom, Peter D. Skelton, Scott J. Josiah, Jason M. Gilsdorf, Dallas R. Virchow, James A. Brandle, Anil K. Jayaprakash, Kent M. Eskridge, Kurt C. VerCauteren

  Nontimber forest products (food, herbal medicinals, and woody floral and handicraft products) produced in forest, agroforestry, and horticultural systems can be important sources of income toNontimber forest products (food, herbal medicinals, and woody floral and handicraft products) produced in forest, agroforestry, and horticultural systems can be important sources of income to landowners. White-tailed deer (Odocoileus virginianus) can reduce the quality, quantity, and profitability of forest products by browsing twigs and rubbing stems, resulting in direct and indirect losses to production enterprises. We evaluated deer damage (frequency and intensity of browsing and rubbing) sustained by 26 species of trees and shrubs, the relationships among morphological features of trees and shrubs to damage levels, and the economic impacts of deer damage on the production of nontimber forest products. Levels of browsing were high (frequency >93% and intensity >50%) in most species of trees and shrubs, with the highest intensity (>60%) occurring in chinese chestnut (Castanea mollisima) and dogwood (Cornus spp.), and the lowest (<20%) in ginkgo (Ginkgo biloba), curly willow (Salix matsudana), 'Scarlet Curls' curly willow, smooth sumac (Rhus glabra), and pussy willow (Salix caprea). Species of trees or shrubs with one or a few stout stems unprotected by dense branching [e.g., american elderberry (Sambucus canadensis), smooth sumac, and curly willow] sustained the most damage by rubbing. Trees and shrubs with many small diameter stems or with dense tangled branching [e.g. redozier dogwood (Cornus sericea), forsythia (Forsythia suspensa), 'Flame' willow (Salix alba), and 'Streamco' basket willow (Salix purpurea)] were damaged the least by rubbing. Annual economic costs of deer damage to producers of nontimber forest products can range from $26/acre for pussy willow to $1595/acre for curly willow.

• Regional assessment on influence of landscape configuration and connectivity on range size of white-tailed deer.

  Authors: W. David Walter, Kurt C. VerCauteren, Henry III Campa, William R. Clark, Justin W. Fischer, Scott E. Hygnstrom, Nancy E. Mathews, Clayton K. Nielsen, Eric M. Schauber, Timothy R. Van Deelen, Scott R. Winterstein

  Variation in the size of home range of white-tailed deer (Odocoileus virginianus) has broad implications for managing populations, agricultural damage, and disease spread and transmission. Size ofVariation in the size of home range of white-tailed deer (Odocoileus virginianus) has broad implications for managing populations, agricultural damage, and disease spread and transmission. Size of home range of deer also varies seasonally because plant phenology dictates the vegetation types that are used as foraging or resting sites. Knowledge of the landscape configuration and connectivity that contributes to variation in size of home range of deer for the region is needed to fully understand differences and similarities of deer ecology throughout the Midwest. We developed a research team from four Midwestern states to investigate how size of home range of deer in agro-forested landscapes is influenced by variations in landscape characteristics that provide essential habitat components. We found that for resident female deer, annual size of home range in Illinois (mean = 0.99 km²), Michigan (mean = 1.34 km²), Nebraska (mean = 1.20 km²), and Wisconsin (mean = 1.47 km²) did not differ across the region (F ₃,₁₇₅ = 0.42, P = 0.737), but differences between agricultural growing and nongrowing periods were apparent. Variables influencing size of home range included: distance to forests, roads, and urban development from the centroid of deer home range, and percent of crop as well as four landscape pattern indices (contrast-weighted edge density, mean nearest neighbor, area-weighted mean shape index, and patch size coefficient of variation). We also identified differences in model selection for four landscapes created hierarchically to reflect levels of landscape connectivity determined from perceived ability of deer to traverse the landscape. Connectivity of selected forested regions within agro-forested ecosystems across the Midwest plays a greater role in understanding the size of home ranges than traditional definitions of deer habitat conditions and landscape configuration.

• Response of Deer to Containment by a Poly-Mesh Fence for Mitigating Disease Outbreaks.

  Authors: Michael J. Lavelle, Justin W. Fischer, Scott E. Hygnstrom, Joshua J. White, Aaron M. Hildreth, Gregory E. Phillips, Kurt C. VerCauteren

  Rapidly deployable and effective methods are needed to contain free-ranging deer (Odocoileus spp.) during acute disease outbreaks. We evaluated efficacy of a 2.1-m-tall polypropylene mesh (poly-mesh)Rapidly deployable and effective methods are needed to contain free-ranging deer (Odocoileus spp.) during acute disease outbreaks. We evaluated efficacy of a 2.1-m-tall polypropylene mesh (poly-mesh) fence for containing >or=15 free-ranging white-tailed deer (O. virginianus) within a 42-ha area in eastern Nebraska, USA. We observed a 99% decrease in deer leaving the enclosure area after we installed fencing (1 deer jumped; 0.02 deer/hr) compared with prefence rates (5.26 deer/hr). However, 8 deer (53% of censused population) escaped the enclosure during a census drive after our study. Poly-mesh fencing may be effective in temporarily containing free-ranging deer during minimally disruptive deer removal actions such as trapping or sharpshooting.