40 research outputs found

    White-tailed deer habitats in the central Black Hills

    No full text
    White-tailed deer (Odocoileus virginianus dacotensis Zimm.) numbers in the central Black Hills have declined since the middle 1970s. Population status has been documented by a decline in hunter success, deer reproductive success, and fawn survival. Most management agencies believe habitat deterioration is the primary cause of population decline in the Black Hills. We evaluated habitat selection for a white-tailed deer herd in the central Black Hills of South Dakota and Wyoming. From July 1993-July 1996, 73 adult and yearling doe and 12 adult and yearling buck white-tailed deer were radiocollared and visually monitored. Habitat Information was collected at 4,662 white-tailed deer locations and 1,087 random locations. During winter, white-tailed deer selected ponderosa pine- (Pinus ponderosa P. C. Lawson) deciduous and burned pine cover types. Overstory-understory habitats selected included pine/grass-forb, pine/bear-berry (Arctostaphylos uva-ursi (L.) Spreng.), pine/snowberry (Symphoricarpos albus L.), burned pine/grass-forb, and pine/shrub habitats. Structural stages selected included sapling-pole pine stands with 70% canopy cover, burned pine sapling-pole and saw-timber stands with 40% canopy cover. During summer, white-tailed deer selected pine-deciduous, aspen (Populus tremuloides Michx.), aspen-coniferous, spruce (Picea glauca (Moench) Voss), and spruce-deciduous cover types. Overstory-understory habitats selected included pine/juniper Juniperus communis L.), aspen/shrubs, spruce/juniper, and spruce/shrub habitats. Structural stages selected included pine, aspen, and spruce sapling pole stands with all levels (0-40%, 41-70%,71-100%) of canopy cover. Results supported low habitat quality as a factor involved with the decline of the deer population. We recommend that habitat management techniques, such as aspen regeneration and prescribed burns, be used to Improve the habitat base in the central Black Hills.The Journal of Range Management archives are made available by the Society for Range Management and the University of Arizona Libraries. Contact [email protected] for further information.Migrated from OJS platform August 202

    A study of risk factors for acquisition of Epstein‐Barr virus and its subtypes

    Get PDF
    Background. Risk factors for primary infection with Epstein-Barr virus (EBV) and its subtypes have not been fully investigated. <br/> Methods. Questionnaires and serum samples from a total of 2006 students who entered Edinburgh University in 1999–2000 were analyzed to examine risk factors for EBV seropositivity, both overall and by EBV type. <br/> Results. The prevalence of EBV seropositivity was significantly increased among females, older students, those who had lived in tropical countries, those with siblings, and those who were sexually active, particularly if they had had numerous sex partners. Risk was lower (1) among students who always used a condom than among those who had sexual intercourse without one and (2) among female oral-contraceptive users than among sexually active nonusers. Risk factors for type 1 EBV infection were similar to those for EBV overall. No associations were found between nonsexual risk factors and type 2 infection. Sexual activity increased the risk of type 2 infection, but the increase in risk with number of sex partners was less consistent than for type 1 infections. Dual infection was uncommon, but the patterns of risk appeared to be similar to those of type 1 infection. <br/> Conclusion. This study provides further evidence that EBV may be sexually transmitted and some suggestion that the risk factors for type 1 and type 2 infection differ

    The role of puberty on physical and brain development: A longitudinal study in male Rhesus Macaques

    No full text
    This study examined the role of male pubertal maturation on physical growth and development of neurocircuits that regulate stress, emotional and cognitive control using a translational nonhuman primate model. We collected longitudinal data from male macaques between pre- and peri-puberty, including measures of physical growth, pubertal maturation (testicular volume, blood testosterone -T- concentrations) and brain structural and resting-state functional MRI scans to examine developmental changes in amygdala (AMY), hippocampus (HIPPO), prefrontal cortex (PFC), as well as functional connectivity (FC) between those regions.Physical growth and pubertal measures increased from pre- to peri-puberty. The indexes of pubertal maturation -testicular size and T- were correlated at peri-puberty, but not at pre-puberty (23 months). Our findings also showed ICV, AMY, HIPPO and total PFC volumetric growth, but with region-specific changes in PFC. Surprisingly, FC in these neural circuits only showed developmental changes from pre- to peri-puberty for HIPPO-orbitofrontal FC. Finally, testicular size was a better predictor of brain structural maturation than T levels -suggesting gonadal hormones-independent mechanisms-, whereas T was a strong predictor of functional connectivity development. We expect that these neural circuits will show more drastic pubertal-dependent maturation, including stronger associations with pubertal measures later, during and after male puberty

    Improving the Cost-Effectiveness of Ecosystem Management: An Application to Waterfowl Production

    No full text
    Species conservation is an important global policy issue. The design of cost-effective species conservation programs requires resource managers to choose from a suite of conservation activities and sites. This article determines cost-effective conservation strategies for waterfowl using a bioeconomic modeling framework, which is developed using a biological simulation model for waterfowl and regression analysis. The model accounts for (a) a broad range of land-use and direct wildlife conservation activities, (b) the effect of landscape heterogeneity, and (c) interactions between conservation activities. Results indicate that accounting for the three factors listed above can improve the cost-effectiveness of waterfowl conservation on agricultural land. Copyright 2007, Oxford University Press.
    corecore