Diets,Movements, and Consequences of Providing Wildlife Food Plots for White-Tailed Deer in Central North Dakota

ABSTRACT White-tailed deer (Odocoileus virginianus) in North Dakota, USA, have greatly increased over the past 100 years due to conversion of prairie to agriculture, planting of tree rows, regulated hunting, and extirpation of large predators. In support of management to maintain harvestable big game while minimizing depredation damage to agriculture, the North Dakota Game and Fish Department manages wildlife management areas (WMAs) where planted trees and food plots provide habitat and public hunting. These WMAs are typically surrounded by agricultural fields, and management that concentrates deer in these areas may expose surrounding agricultural producers to increased depredation. We investigated diets, habitat use, and movements of white-tailed deer at a large WMA in central North Dakota (Lonetree WMA) to understand how the animals are responding to management designed to enhance wildlife populations. We also evaluated survival of white-tailed deer for an improved understanding of the recent trend for population growth. Diets of deer varied seasonally, including a relatively high proportion of crops from food plots in winter and mostly herbaceous forbs and browse during spring and summer. Data from radiocollared animals and biweekly spotlight surveys revealed that deer are being drawn from a relatively large area to Lonetree WMA during fall and winter. Hunting was the most important cause of mortality, but annual survival of adult and fawn females exceeded 80%. The original purpose of food plots at Lonetree WMA was to alleviate depredation on adjacent private lands. Depredation has been limited, but the multiyear trend of increased deer numbers is a new concern. A possible consequence of provisioning white-tailed deer with food plots during winter when some starvation would normally occur could be for the population to exceed a threshold above which regulated hunting will be unable to prevent irruptive growth. Research on how food plots influence winter survival is needed to inform management and prevent possible rapid increase in white-tailed deer populations across the prairie-coteau region of central North Dakota.     

Indirect Effects of a Keystone Herbivore Elevate Local Animal Diversity

Abstract: We quantified indirect effects of white-tailed deer (Odocoileus virginianus) on ground-dwelling herpetofauna and invertebrates in Cuyahoga Valley National Park, Ohio, USA. We placed cover boards at 12 sites, each consisting of a 10 × 10-m fenced (exclosure) plot and an unfenced (control) plot. Periodically, during May-December 2004 and May-September 2005, we counted salamanders, snakes, and a variety of invertebrate taxa. Salamander, snake, and gastropod abundance as well as invertebrate richness (no. of species or higher level taxa) were higher in control than exclosure plots. Our findings suggest that management actions taken to regulate deer densities could have the unintended effect of reducing local animal diversity.     

Adjacent Habitat Influence on Stink Bug (Hemiptera: Pentatomidae) Densities and the Associated Damage at Field Corn and Soybean Edges

The local dispersal of polyphagous, mobile insects within agricultural systems impacts pest management. In the mid-Atlantic region of the United States, stink bugs, especially the invasive Halyomorpha halys (Stål 1855), contribute to economic losses across a range of cropping systems. Here, we characterized the density of stink bugs along the field edges of field corn and soybean at different study sites. Specifically, we examined the influence of adjacent managed and natural habitats on the density of stink bugs in corn and soybean fields at different distances along transects from the field edge. We also quantified damage to corn grain, and to soybean pods and seeds, and measured yield in relation to the observed stink bug densities at different distances from field edge. Highest density of stink bugs was limited to the edge of both corn and soybean fields. Fields adjacent to wooded, crop and building habitats harbored higher densities of stink bugs than those adjacent to open habitats. Damage to corn kernels and to soybean pods and seeds increased with stink bug density in plots and was highest at the field edges. Stink bug density was also negatively associated with yield per plant in soybean. The spatial pattern of stink bugs in both corn and soybeans, with significant edge effects, suggests the use of pest management strategies for crop placement in the landscape, as well as spatially targeted pest suppression within fields.     

Habitat Quality Following Mid-Rotation Treatment in Conservation Reserve Program Pines

ABSTRACT Evaluation of habitat management practices at mid-rotation is needed for pine (Pinus spp.) plantations enrolled in cost-share programs. Plantations established in abandoned agricultural fields may have different understory plant communities than those with a long history of forest cover. Mid-rotation pine plantations often have a hardwood midstory that limits development of early succession habitat components important to white-tailed deer (Odocoileus virginianus; deer) and northern bobwhite (Colinus virginianus; bobwhite). We treated with imazapyr herbicide and prescribed burning (HB) 11 thinned, 13–22-year-old pine plantations in the Upper East Gulf Coastal Plain of Mississippi, USA, enrolled in cost-share programs, and we sampled plant community response during the summers of 2003 and 2004, years 1 and 2 posttreatment. The HB treatment created a more open structure with greater coverage of debris and herbaceous plants than in controls. Increased forb coverage in HB plots yielded a more seasonally diverse foraging base for deer. Horizontal screening cover developed slowly in HB plots and was more abundant in control plots. Autumn and winter food-plant coverage for bobwhite was provided by either treatment, but accessibility was improved in HB plots relative to controls. Bobwhite nesting cover was improved by HB relative to controls but was still of marginal quality. Brood-rearing habitat was precluded in both treatments due to lack of bare ground. Our results indicate that imazapyr followed by prescribed fire is a beneficial tool for creating early succession habitat for deer and bobwhite in mid-rotation pine plantations with a history of agricultural use. Continued management with periodic prescribed fire and overstory thinning should be instituted to maintain and perhaps improve these conditions.     

Effects of crop field characteristics on nocturnal winter use by American woodcock

Since the late 1960s, American woodcock (Scolopax minor) have undergone population declines because of habitat loss. Previous research suggested ridge and furrow topography in conventionally tilled soybean fields provided critical nocturnal cover as birds foraged on earthworms. However, the use of no-till technology has increased and many fields now lack ridge and furrow topography. We assessed woodcock winter nocturnal foraging habitat use given recent changes in agricultural technology, and investigated how field treatment, earthworm abundance, and environmental variables affect the selection of nocturnal foraging sites. We counted woodcock along transects in 5 field treatments twice in each of 67 fields during December–March 2008–2009 and 72 fields during December–March 2009–2010. During both seasons, we collected earthworm and soil samples from a subset of fields of each field treatment. Woodcock densities were at least twice as high in no-till soybean fields planted after corn and in undisked corn fields with mowed stalks than in other field treatments. No-till soybean planted after corn and undisked corn fields contained ridge and furrow topography, whereas other crops did not, and earthworms were at least 1.5 times more abundant in no-till soybean fields than other field treatments. Ridges and furrows in no-till soybean fields planted after corn and undisked corn fields may provide wintering woodcock with thermal protection and concealment from predators. No-till soybean fields planted after corn offered the additional benefit of relatively high food availability. The presence of ridge and furrow topography can be used to predict woodcock field use on the wintering grounds in agricultural areas. Farmers can provide nocturnal winter foraging sites for woodcock by delaying field disking and leaving ridge and furrow topography in crop fields. © 2011 The Wildlife Society.     

Genetic assessment of environmental features that influence deer dispersal: implications for prion-infected populations

The landscape can influence host dispersal and density, which in turn, affect infectious disease transmission, spread, and persistence. Understanding how the landscape influences wildlife dispersal and pathogen epidemiology can enhance the efficacy of disease management in natural populations. We applied landscape genetics to examine relationships among landscape variables, dispersal of white-tailed deer hosts and transmission/spread of chronic wasting disease (CWD), a fatal prion encephalopathy. Our focus was on quantifying movements and population structure of host deer in infected areas as a means of predicting the spread of this pathology and promoting its adaptive management. We analyzed microsatellite genotypes of CWD-infected and uninfected deer from two disease foci (Southern Wisconsin, Northern Illinois). We quantified gene flow and population structure using F _ST, assignment tests, and spatial autocorrelation analyses. Gene flow estimates were then contrasted against a suite of landscape variables that potentially mediate deer dispersal. Forest fragmentation and grassland connectivity promoted deer movements while rivers, agricultural fields and large urbanized areas impeded movement. Landscape variables, deer dispersal, and disease transmission covaried significantly and positively in our analyses. Habitats with elevated host gene flow supported the concept of dispersal-mediated CWD transmission by reflecting a concomitant, rapid CWD expansion. Large, interrelated social groups isolated by movement barriers overlapped disease foci, suggesting that philopatry exacerbated CWD transmission. Our results promote adaptive management of CWD by predicting patterns of its spread and identifying habitats at risk for invasion. Further, our landscape genetics approach underscores the significance of topography and host behavior in wildlife disease transmission.     

DISPERSAL BY YEARLING MALE WHITE-TAILED DEER AND IMPLICATIONS FOR MANAGEMENT

Abstract: The scale at which populations use the landscape influences ecological processes and management decisions. Dispersal and home-range size define the scale of landscape use for many large-mammal species. We measured dispersal and home-range size of yearling male white-tailed deer (Odocoileus virginianus) in southern Texas, and compared our results to values from the literature to understand the implications of dispersal in management of deer populations. We used radiotelemetry to monitor 22 yearling deer on 1 study site from October 1998 to October 1999, and 27 yearling deer on a second study site from October 1999 to October 2000. On the 2 study sites, 68% and 44% of yearling deer established new areas of use 4.4 ± 1.0 km and 8.2 ± 4.3 km, respectively, from the center of their autumn home range. Yearling males with spike antlers (2 points) were less likely to disperse than yearlings with fork antlers (>2 points) on 1 study site. Computer simulation showed that the scale at which deer use the landscape is large compared to property sizes in southern Texas and probably in other areas of the white-tailed deer's range. Differences in scale between land ownership patterns and landscape use by deer may result in a failure to meet management objectives and conflict among managers. High harvest rates for male deer occur in part because deer movements are large relative to property size, creating a “tragedy of the commons.” Cooperative management groups are beneficial if all landowners in an area agree on management objectives. Otherwise, deer-proof fences often are erected to reduce conflicts among property owners.     

Occurrence patterns of crop‐foraging sika deer distribution in an agriculture–forest landscape revealed by nitrogen stable isotopes

Conflicts arising from the consumption of anthropogenic foods by wildlife are increasing worldwide. Conventional tools for evaluating the spatial distribution pattern of large terrestrial mammals that consume anthropogenic foods have various limitations, despite their importance in management to mitigate conflicts. In this study, we examined the spatial distribution pattern of crop‐foraging sika deer by performing nitrogen stable isotope analyses of bone collagen. We evaluated whether crop‐foraging deer lived closer to agricultural crop fields during the winter and spring, when crop production decreases. We found that female deer in proximity to agricultural crop fields during the winter and spring were more likely to be crop‐foraging individuals. Furthermore, the likelihood of crop consumption by females decreased by half as the distance to agricultural crop fields increased to 5–10 km. We did not detect a significant trend in the spatial distribution of crop‐foraging male deer. The findings of spatial distribution patterns of crop‐foraging female deer will be useful for the establishment of management areas, such as zonation, for efficient removal of them.     

Landscape-scale habitat characteristics and neonatal white-tailed deer survival

Landscape-level habitat characteristics affect neonatal white-tailed deer (Odocoileus virginianus) survival. Little is known, however, about how changes in maternal habitat use after parturition affect neonate survival. We quantified survival rates and determined if neonate survival to 8 weeks was affected by weekly maternal habitat use in the agricultural Glaciated Plains (GP) and forest-grassland Ozark (OZ) eco-regions of Missouri, USA. We captured 127 pregnant female deer during 2015–2017, and fitted each with a global positioning system (GPS) radio-collar and vaginal implant transmitter (VIT). We captured 226 neonatal deer during 2015–2017, fitted each with an expandable radio-collar, and monitored survival status daily. We estimated weekly maternal home ranges and calculated habitat metrics within these home ranges. We used the Kaplan-Meier estimator to calculate 8-week survival estimates and Cox proportional hazards models to investigate the influence of habitat metrics on neonate survival. The 8-week survival estimates were 0.43 (95% CI = 0.35–0.54) and 0.47 (95% CI = 0.38–0.57) in the GP and OZ, respectively. Both of these survival estimates were lower than expected but particularly so in the GP because it is dominated by agricultural fields, a land cover type typically associated with high survival. Neonate survival in the GP was negatively correlated with the amount of edge and forest patch size within maternal home ranges. In the OZ, female neonate survival was positively correlated with birth mass, male neonate survival was not affected by birth mass, and survival of both sexes was negatively correlated with grassland patch density. We suspect these habitat metrics were related to predator searching efficiency and abundance. In the highly fragmented GP, predators might be able to easily search the largest cover habitat patches, whereas in the more contiguous OZ landscape, where cover habitat patch sizes were > 10 times the size of patches in the GP, large patches might be difficult for predators to search efficiently. Therefore, we recommend managers consider the larger landscape context when making habitat management decisions to increase white-tailed deer population productivity. © 2019 The Wildlife Society.     

Landscape Features Fail to Explain Spatial Genetic Structure in White-Tailed Deer Across Ohio,USA

Landscape features influence wildlife movements across spatial scales and have the potential to influence the spread of disease. Chronic wasting disease (CWD) is a fatal prion disease affecting members of the family Cervidae, particularly white-tailed deer (Odocoileus virginianus), and the first positive CWD case in a wild deer in Ohio, USA, was recorded in 2020. Landscape genetics approaches are increasingly used to better understand potential pathways for CWD spread in white-tailed deer, but little is known about genetic structure of white-tailed deer in Ohio. The objectives of our study were to evaluate spatial genetic structure in white-tailed deer across Ohio and compare the support for isolation by distance (IBD) and isolation by landscape resistance (IBR) models in explaining this structure. We collected genetic data from 619 individual deer from 24 counties across Ohio during 2007–2009. We used microsatellite genotypes from 619 individuals genotyped at 11 loci and haplotypes from a 547-base pair fragment of the mitochondrial DNA control region. We used spatial and non-spatial genetic clustering tests to evaluate genetic structure in both types of genetic data and empirically optimized landscape resistance surfaces to compare IBD and IBR using microsatellite data. Non-spatial genetic clustering tests failed to detect spatial genetic structure, whereas spatial genetic clustering tests indicated subtle spatial genetic structure. The IBD model consistently outperformed IBR models that included land cover, traffic volume, and streams. Our results indicated widespread genetic connectivity of white-tailed deer across Ohio and negligible effects of landscape features. These patterns likely reflect some combination of minimal resistive effects of landscape features on white-tail deer movement in Ohio and the effects of regional recolonization or translocation. We encourage continued CWD surveillance in Ohio, particularly in the proximity of confirmed cases. © 2021 The Wildlife Society. This article has been contributed to by US Government employees and their work is in the public domain in the USA.     

The regeneration of pioneer tree species under browsing pressure of Sika deer in an evergreen oak forest

The effects of Sika deer (Cervus nippon) browsing on the regeneration of pioneer species were studied in relation to canopy gaps in a warm temperate evergreen oak forest in Kasugayama, Nara City. Four study sites, three in canopy gaps and one under a closed canopy, were selected and each divided into fenced and unfenced plots. Under the closed canopy, seedlings of all the pioneer species died irrespective of browsing pressure. However, in the canopy gap sites, seedlings of the pioneer species could establish and grow well. The seedling survival ratio in the fenced plots in the canopy gaps was >60% 1 year after germination. However, in the unfenced plots, only <20% of the seedlings survived 1 year, with all dying within 3 years after germination. Thus, the regeneration of pioneer trees in this forest was strongly inhibited by deer browsing. Successful regeneration of a pioneer,Zanthoxylum ailanthoides, occurred for several years even after two major wind disturbances during the past 90 years. This may be due to less browsing pressure from the deer.     

White-Tailed Deer Movements in a Chronic Wasting Disease Area in South-Central Wisconsin

Abstract: To focus white-tailed deer (Odocoileus virginianus) management within a chronic wasting disease-infected area in south-central Wisconsin, USA, we assessed deer movements and related dispersal to variation in landscape pattern, deer density, and harvest intensity. We radiocollared and monitored 165 deer between 2003 and 2005. Yearling males that dispersed (45%) had greater forest edge (i.e., fragmentation) within natal home ranges. Exploratory movements were rare for adult females. Transient and migratory movements were rare among all deer (<5%). Although yearling males have low chronic wasting disease prevalence rates, they may be infected before dispersal due to variable incubation times. Managers should increase yearling male harvest and consider removing young males in areas of higher forest edge.     

Leukoencephalomalacia in a white-tailed deer from North Carolina

Leukoencephalomalacia similar to equine leukoencephalomalacia occurred in a white-tailed deer (Odocoileus virginianus) from North Carolina. The deer was recumbent and stuporous when presented for examination. It was believed that the disease resulted from ingestion of moldy field corn, infected with Fusarium moniliforme.     

Influence of Landscape Composition and Structure on Antler Size of White-Tailed Deer

Abstract: Cause for spatial variation in phenotypic quality of white-tailed deer (Odocoileus virginianus) populations is of great interest to wildlife managers. Relating phenotypic variation of populations to large-scale land-use patterns may provide insight into why populations exhibit spatial variation and elucidate how management can influence population phenotype. We used an information-theoretic approach to relate average antler size of 203 deer populations to composition and structure of the habitat occupied by those populations. We used interspersion, edge, and diversity indices to represent habitat structure and percentage of area in vegetation types to represent habitat composition. Landscape composition was a better predictor of deer population antler size than was landscape structure. Percentages of the management unit in agriculture, pasture, and pine forest were variables commonly found in the region-specific set of best models. Model-averaged estimates of agriculture and pasture parameters were always positive and estimates of pine forest parameters were always negative, which suggests that land-use types that promote growth of early successional herbaceous plants will positively influence antler size and, most likely, body growth and reproduction of white-tailed deer populations. Conversely, our findings suggest landscapes dominated by pine forests did not provide optimal amounts of quality forages for white-tailed deer. Pine forest effects should be mitigated using a combination of increased harvest to lower deer density and silvicultural practices like thinning, prescribed burning, and selective herbicide applications that stimulate growth of high-quality forages beneath the forest canopy to improve deer phenotypic quality.     

Survival,cause-specific mortality,and population growth of white-tailed deer in western Virginia

Understanding the role of recruitment in population dynamics of white-tailed deer (Odocoileus virginianus) is important for management. In the central Appalachian Mountains, deer are part of a largely forested ecosystem that supports 3 carnivore species thought to be capable of influencing white-tailed deer recruitment: black bears (Urus americanus), coyotes (Canis latrans), and bobcats (Lynx rufus). Yet little is known about predation, how other environmental factors influence recruitment, or the importance of neonate survival to white-tailed deer population performance in the region. Our objectives were to identify causes of mortality for neonates, analyze effects of landscape attributes on survival of neonates, estimate survival rates for neonates and adult female white-tailed deer, and to model population growth trends based on current vital rates and hypothetical harvest and neonate survival scenarios. During 2019–2020, we captured 57 neonate deer in Bath County, Virginia, USA, by monitoring 38 pregnant females equipped with global positioning system collars and vaginal implant transmitters and by conducting transect searches for recently born neonates. We observed 37 neonate mortalities and identified cause of death using field and genetic evidence. Mortalities included 28 predation events and 9 deaths from other causes (e.g., abandonment, malnutrition, disease). Black bears accounted for 48.6% of neonate mortalities, and 64.2% of predation events (n = 18), followed by bobcats (n = 5) and coyotes (n = 3). Annual survival for adult female deer was 0.871 and neonate survival to 12 weeks old was 0.310. Elevation was a significant predictor of neonate survival; mortality risk increased 20% for every 100-m increase in elevation. Models of annual population growth using observed vital rates predicted an increasing population (λ = 1.10). A 10% increase in female harvest would still result in a potential population increase of 2% (λ = 1.02), but a 20% increase in harvest rate would result in a potential 7% decline (λ = 0.93). Neonate survival was higher near fertile valley bottoms and lower along forested ridges characterized by shallow, infertile soils and limited edge or early successional forests. While predation, largely influenced by black bears, was the leading cause of neonate mortality and contributed to low neonate survival, we observed little evidence of population decline, and suggest there is opportunity for a modest increase in harvest of female deer.     

Resource partitioning between sympatric columbian white-tailed and black-tailed deer in western Oregon

We studied resource partitioning between sympatric populations of Columbian white-tailed (CWTD; Odocoileus virginianus leucurus) and black-tailed (BWTD) deer (O. odocoileus hemionus columbianus) in western Oregon to understand potential mechanisms of coexistence. We used horseback transects to describe spatial distributions, population overlap, and habitat use for both species, and we studied diets with microhistological analysis of fecal samples. Distribution patterns indicated that white-tailed and black-tailed deer maintained spatial separation during most seasons with spatial overlap ranging from 5%–40% seasonally. Coefficients of species association were negative, suggesting a pattern of mutual avoidance. White-tailed deer were more concentrated in the southern portions of the study area, which was characterized by lower elevations, more gradual slopes, and close proximity to streams. Black-tailed deer were more wide ranging and tended to occur in the northern portions of the study area, which had higher elevations and greater topographical variation. Habitat use of different vegetative assemblages was similar between white-tailed and black-tailed deer with overlap ranging from 89%–96% seasonally. White-tailed deer used nearly all habitats available on the study area except those associated with conifers. White-tailed deer used oak-hardwood savanna shrub, open grassland, oak-hardwood savanna, and riparian habitats the most. Black-tailed deer exhibited high use for open grassland and oak-hardwood savanna shrub habitats and lower use of all others. The 2 subspecies also exhibited strong seasonal similarities in diets with overlap ranging from 89% to 95%. White-tailed deer diets were dominated by forbs, shrubs, grasses, and other food sources (e.g., nuts and lichens). Columbian black-tailed deer diets were dominated mostly by forbs and other food sources. Seasonal diet diversity followed similar patterns for both species with the most diverse diets occurring in fall and the least diverse diets in spring. High overlap in habitat use and diets resulted in high trophic overlap (81–85%) between white-tailed and black-tailed deer; however, the low spatial overlap reduced the potential for exploitative competition but may have been indicative of inference competition between the species. Diverse habitat and forage opportunities were available on the study area due to heterogeneous landscape characteristics, which allowed ecological separation between white-tailed and black-tailed deer despite similarities in diets and habitat use. We make several recommendations for management of CWTD, a previously threatened species, based on the results of our study. © 2011 The Wildlife Society.     

Evaluating the Mechanisms of Landscape Change on White-Tailed Deer Populations

Understanding how landscape change influences the distribution and densities of species, and the consequences of these changes, is a central question in modern ecology. The distribution of white-tailed deer (Odocoileus virginianus) is expanding across North America, and in some areas, this pattern has led to an increase in predators and consequently higher predation rates on woodland caribou (Rangifer tarandus caribou)—an alternate prey species that is declining across western Canada. Understanding the factors influencing deer distribution has therefore become important for effective conservation of caribou in Canada. Changing climate and anthropogenic landscape alteration are hypothesized to facilitate white-tailed deer expansion. Yet, climate and habitat alteration are spatiotemporally correlated, making these factors difficult to isolate. Our study evaluates the relative effects of snow conditions and human-modified habitat (habitat alteration) across space on white-tailed deer presence and relative density. We modeled deer response to snow depth and anthropogenic habitat alteration across a large latitudinal gradient (49° to 60°) in Alberta, Canada, using motion-sensitive camera data collected in winter and spring from 2015 to 2019. Deer distribution in winter and spring were best explained by models including both snow depth and habitat alteration. Sites with shallower snow had higher deer presence regardless of latitude. Increased habitat alteration increased deer presence in the northern portion of the study area only. Winter deer density was best explained by snow depth only, whereas spring density was best explained by both habitat alteration and the previous winter's snow depth. Our results suggest that limiting future habitat alteration or restoring habitat can alter deer distribution, thereby potentially slowing or reversing expansion, but that climate plays a significant role beyond what managers can influence. © 2020 The Wildlife Society.     

Effectiveness of Wildlife Underpasses and Fencing to Reduce Wildlife-Vehicle Collisions

ABSTRACT Transportation planners are increasingly incorporating roadway design features to mitigate impacts of highways on wildlife and to increase driver safety. We used camera and track surveys to evaluate wildlife use before and after construction of 3 wildlife underpasses and associated fencing on a new section of United States Highway 64 in Washington County, North Carolina, USA. We recorded 242 occasions of white-tailed deer (Odocoileus virginianus) use of underpass areas before highway construction began. Following completion of the highway, we collected 2,433 photographs of 9 species with deer representing 93% of all crossings. Adjusting for differences in number of monitoring days, white-tailed deer use of underpass areas averaged 6.7 times greater after the new highway and underpasses were completed. We recorded 3,614 wildlife crossings of ≥20 species based on track counts, representing most medium and large mammals known to occur in the area and several reptiles and birds. After completion of the highway, we documented wildlife mortality due to vehicle collisions during a 13-month period and recorded 128 incidences representing ≥24 species. Within fenced highway segments, mortalities were lowest near underpasses and increased with distance from the underpasses. However, we also documented more mortalities in fenced areas compared with unfenced areas. With greater distance from an underpass, animals with smaller home ranges seemed less likely to reach the underpass and instead attempted to climb over or crawl under fencing. Based on collision reports from adjacent highway sections, the new section of United States Highway 64 experienced approximately 58% fewer wildlife mortalities (primarily white-tailed deer), suggesting underpasses and fencing reduced the number of deer-vehicle collisions. Continuous fencing between underpasses may further reduce the number of vehicle collisions for deer but additional design features (e.g., buried fencing) should be considered for other wildlife species.     

Effect of domestic cattle on the condition of female white-tailed deer in southern pine-bluestem forests,USA

Effect of domestic cattle stocking on the nutritional condition of white-tailed deerOdocoileus virginianus (Zimmermann, 1780) was assessed using physiological indices of collected specimens. Three study areas were delineated in McCurtain County, Oklahoma (heavy cattle stocking), and Howard (moderate to light cattle stocking) and Pike (no cattle stocking) counties, Arkansas that were similar with respect to soils and vegetation but differed with respect to cattle stocking rate. Female white-tailed deer were collected from study areas in February and August 1987–1988 to assess nutritional condition. Deer collected from study areas exposed to cattle grazing in February had lower carcass weights, fat attributes (femur marrow and kidney fat), and reproductive rates (fetuses/doe) than deer that were not exposed to cattle grazing. In August, deer collected from the moderate cattle area had heavier eviscerated carcass weights, serum glucose, albumin, and albumin/globulin ratios than deer collected from the heavy cattle area. Results suggest that if cattle are removed from managed forests in winter, nutritional condition of deer would be improved because of reduced competition for food.     

Trap cropping to manage green vegetable bug Nezara viridula (L.) (Heteroptera: Pentatomidae) in sweet corn in New Zealand

Abstract

• 1 The use of trap crops to reduce green vegetable bug (GVB) Nezara viridula (L.) (Heteroptera: Pentatomidae) damage to process sweet corn Zea mays (L.) was investigated in three field experiments.
• 2 In the first season, small plots (2.7 m by 10 m) of white mustard Sinapis alba (L.) with pea Pisum sativum (L.) were sown along a crop border and compared with sweet corn alone.
• 3 In the second season, black mustard Brassica nigra (L.) was sown at two sowing dates (14 days apart) and compared with a sweet corn control, to examine how the maturity of the trap crop affected numbers of GVB trapped.
• 4 A field scale experiment was also conducted to determine the effectiveness of black mustard as a trap crop to protect larger areas of sweet corn from GVB.
• 5 In all three experiments, GVB populations were much higher on the trap crops compared with the sweet corn.
• 6 In both small plot experiments, GVB were contained largely within the trap crop for 2 weeks until the sweet corn was harvested.
• 7 The field scale experiment demonstrated the efficacy of the trap cropping technique to protect larger areas of crop from GVB.
• 8 Percentages of damaged sweet corn cobs in the outside row of fields protected by a trap crop were 0% and 1%, respectively, compared with 11% and 22% in control fields.
• 9 Trap cropping is recommended as an effective strategy to manage this insect. Options for cultivating or spraying the trap crops to reduce bug survival are discussed.