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

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 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 radio-collared 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.

Evaluation of a New Strategy for Control of Bovine Tuberculosis in Michigan White-Tailed Deer: Year 1 Progress Report

The State of Michigan is striving to eliminate bovine tuberculosis (Tb) infection among free-ranging white-tailed deer in the northeastern Lower Peninsula of the state. Aggressive reduction in the overall deer population abundance may help to further reduce TB prevalence, but this course of action is unacceptable to many hunters and landowners. Targeted culling of sick deer would likely be far more acceptable to these stakeholders, so in the winter of 2003 the Michigan Department of Natural Resources pilot-trialed a new strategy based on live-trapping and Tb-testing of wild deer. The field study was conducted in a township with relatively high TB prevalence within Deer Management Unit 452 in the northeastern Lower Peninsula. Over a 2-month trapping period, 119 individual deer were live-trapped, blood sampled, fitted with a radio-collar, and released. A total of 31 of these deer were subsequently classified as Tb-suspect by at least one of five blood tests employed (however there was a low level of agreement among tests). A delay in testing meant that only six of these suspect deer were culled by sharpshooters before pre-programmed release of their radio-collars, after which they could no longer be located. Mycobacterium bovis was cultured from one of these six suspect deer; the other five were negative on culture. All target deer were located to within shooting range with 1 – 2 days of effort, and all the radio-collars on the apparently-healthy deer dropped off after the intended 90-day interval, and were thereafter recovered for re-use. There was considerable support for this pilot project among hunters, farmers, state and federal agriculture agencies, the media and the general public, and so we recommend that further field trials be undertaken using this technique. The initial focus of these trials should be on improving the efficacy and reliability of the blood testing procedure.

Effectiveness of a White-Tailed Deer Exclusion Fence Based on Traction Limitations of the Hoof: The Slippery Fence

We hypothesized that an exclusion fence could be devised to capitalize on traction limitations of the hooves of white-tailed deer (Odocoileus virginianus). Hexagonal plots (9.8 m wide) enclosed by a 2.4 m field fence with two openings (4.9 m) were established. Data were collected daily on consumption of corn provided (2.27 kg) and events recorded by infrared monitors (IR) for treatment and control sites. Five-day treatment periods consisted of test panels (4.9 m x 2.4 m) placed in plot openings at 0°, 5° and 10° slopes, and lubricant applied at the 10° slope. Deer consumed all corn provided at control sites. At the 10° slope, daily corn consumption decreased (1.50 kg ± 0.26, p < .01), and IR events were lower (p < .01) at treatment sites (23.6 ± 3.2) compared to controls (50.3 ± 9.6). With the addition of a lubricant, corn consumption decreased further (p < .001) to 0.17 kg ± 0.03, and IR recorded events were lower (p < .001) at treatment sites (6.58 ± 0.89) compared to controls (44.8 ± 3.1). Results of this study indicate that traction limitation of the hoof can be exploited.

An Analysis of Anchitherine Equids Across the Eocene–Oligocene Boundary in the White River Group of the Western Great Plains

Anchitherine horses are a subfamily of equids that are abundantly represented in the late Eocene and early Oligocene of North America. This group has been heavily studied in the past, but important questions still remain. Some studies have focused on the Eocene-Oligocene boundary and have used these equids along with other taxa to study mammalian diet and climate change through this interval. I reexamine two anchitherine genera, Mesohippus and Miohippus, from stratigraphic sequences of the White River Group in western Nebraska and southwestern South Dakota. These sequences span the Chadronian (late Eocene), Orellan (early Oligocene), and Whitneyan (early Oligocene) North American land-mammal ages. The most recent revision of these genera was done by Prothero and Shubin (1989). I review the characters used for taxonomic identification. This includes characters such as the hypostyle, the articular facet on the third metatarsal, and dental dimensions. To avoid possible biases caused by combining specimens from different stratigraphic levels, specimens were separated by location and stratigraphic level. The length and width of cheek teeth, and tooth rows were measured on 488 specimens. First molar area serves as a proxy for body mass in horses and other mammals, and can be useful for distinguishing among species. Results indicate that the characters used by Prothero and Shubin were highly variable in anchitherine horses and are not useful for distinguishing between these genera. The development of the articular facet on the third metatarsal may be a function of body size and therefore may be of no more utility than first molar area. Variability in first molar area suggests the presence of three species in the medial and late Chadronian, two species in the Orellan, and at least two species in the Whitneyan. Due to a lack of objective criteria separating Mesohippus from Miohippus, I recommend synonymy of these genera, making Mesohippus a junior subjective synonym.

Scraping Behavior in Male White-tailed Deer as a Potential Means of Transmitting Chronic Wasting Disease

Chronic wasting disease (CWD) has become a concern for wildlife managers and hunters across the United States. High prevalence of chronic wasting disease (CWD) in older male white-tailed deer (Odocoileus virginianus) suggests that sex-specific social behavior may contribute to the spread of the disease among males. Scraping is a marking behavior performed by male white-tailed deer during the rut in which a pawed depression and associated over-hanging branch are marked with saliva, glandular secretions, urine, and feces. We placed 71 and 35 motion-activated cameras on scrapes in DeSoto National Wildlife Refuge in western Nebraska and eastern Iowa from Oct. – Nov. 2005 and Sept. – Nov. 2006, respectively. We recorded 5009 encounters and 1830 direct interactions. We developed an ethogram of behaviors of interest at scrapes. We found that males interacted with scrapes more frequently than females (P < 0.001). Male interactions were more complex, with 69% consisting of ≥2 observed behaviors versus 25% and 13% for females and fawns. We identified individual male deer ≥2.5 years old and determined the minimum number of different scrapes individuals visited and the number of individuals that visit a single scrape. Individuals that appeared on camera ≥5 times visited a mean of 3.9 scrapes (range = 1-15) and traveled a mean minimum distance of 978 m between consecutive scrapes. A mean of 5.1 individuals visited a single scrape, and up to 43% of individuals returned to a scrape previously visited at least once. We modeled Risk Values based on frequency of occurrence, duration, and Threat Values of each behavior, for contacting and transmitting CWD prions at scrapes. Adult males had the highest total Risk Values for contacting CWD prions (114.1) and shedding prions (59.4). The “grasp-lick branch” behavior had the highest Risk Value for adult males for both contacting and transmitting prions. Our study reveals a sex specific social behavior in male white-tailed deer that has the potential to spread chronic wasting disease between adult males in the population.

A Land-Use and Water-Quality History of White Rock Lake Reservoir, Dallas, Texas, Based on Paleolimnological Analyses

White Rock Lake reservoir in Dallas, Texas contains a 150-cm sediment record of silty clay that documents land-use changes since its construction in 1912. Pollen analysis corroborates historical evidence that between 1912 and 1950 the watershed was primarily agricultural. Land disturbance by plowing coupled with strong and variable spring precipitation caused large amounts of sediment to enter the lake during this period. Diatoms were not preserved at this time probably because of low productivity compared to diatom dissolution by warm, alkaline water prior to burial in the sediments. After 1956, the watershed became progressively urbanized. Erosion decreased, land stabilized, and pollen of riparian trees increased as the lake water became somewhat less turbid. By 1986 the sediment record indicates that diatom productivity had increased beyond rates of diatom destruction. Neither increased nutrients nor reduced pesticides can account for increased diatom productivity, but grain size studies imply that before 1986 diatoms were light limited by high levels of turbidity. This study documents how reservoirs may relate to land-use practices and how watershed management could extend reservoir life and improve water quality.

The Unique Challenges and Experiences of African¬-American Women Academicians at Predominantly White Institutions

This session addresses the unique challenges of African-American women academicians at predominantly white institutions. After assessing scholarly literature in this area, most research has and continues, to ignore the interrelationship between race, class and gender. This paper builds on existing literature by offering a discourse that addresses various challenges facing these women.

The Change from Red to White Meat: The Role of Technology

Since 1950, the composition of the U.S. meat diet has shifted markedly from red meats to poultry. For example, from 1970 to 1984, on a percapita basis, beef consumption has declined by 6.4 percent, while chicken and turkey consumptions have increased by 37.9, and 42.5 percent respectively (U.S. Department of Agriculture, 1985). The numerous studies of this phenomenon from the demand side (Chavas, 1983; Braschler, 1983; Nyankori and Miller, 1982; Moschini and Meilke, 1984; Wohlgenant, 1985, Thurman, 1987; Chalfant and Alston, 1988) have failed to achieve a consensus as to whether a change in taste contributed to this shift. One reason for the lack of consensus is that the very large price and quantity changes make it difficult to establish whether consumers are on a new indifference map. But there have been no comparable studies of the nature and causes of the technological change that has made these large consumption and price changes possible. A decrease in the relative price of poultry with respect to red meat is in any case a major explanation of recent shifts in meat consumption patterns. The main reason for such a decrease appears to be a higher rate of technical progress in the poultry industry than in the red meat industry. Substantial productivity gains in both the production and marketing of poultry over the last two decades appears to have been translated into lower retail prices for poultry. Although some productivity gains have taken place in the red meat industry, they have not matched the cost reductions in the poultry industry (Chavas, 1987). Thus, a consumption shift from beef to poultry could possibly be interpreted as a response to changing relative prices, the structural change having occurred in the meat industry. This would imply that, if the beef industry desires to maintain or expand its market, it should seek a decrease in the production and marketing costs of beef.