Contract Research Findings: Mammals

Title:Limitations of thermal infrared imaging for locating neonatal deer in semiarid shrub communities
Journal/Year:Wildlife Society Bulletin/2006
View:Visit Wiley Online Library Wildlife Society Bulletin Volume34, Issue5 December 2006- Limitations of thermal infrared imaging for locating neonatal deer in semiarid shrub communities
Author(s):David A. Butler|Warren B. Ballard|Shawn P. Haskell|Mark C. Wallace
Keywords:capture|deer|detection|fawn|infrared|neonates|Odocoileus spp.|Texas|thermal imaging
Abstract:Neonate capture can be an important part of ungulate research. Systematic grid searching has been the most common method, but it is time consuming and usually requires a large number of people. A variety of methods have been used by wildlife professionals to capture ungulate neonates. We used a Raytheon PalmIR 250 Digital (Raytheon Commercial Infrared, Dallas, Texas) thermal infrared camera during the coolest time of night to search for deer (Odocoileus spp.) neonates in west-central Texas, USA. Using 2 methods (stationary observation and mobile searching), we detected one fawn and captured none. Efficacy of this technology at our study site may have been limited by the lack of a forest canopy and density of shrubs and herbaceous cover on our study site. Ground cover can obscure a bedded fawn, and direct sunlight on bed site habitat can result in false signals. We suggest wildlife professionals consider vegetation parameters, ungulate density, and road quality before purchasing expensive thermal imaging equipment.
Management Implications:The variety of problems encountered during the study make the notion of using thermal infrared imagery to locate and capture neonates impractical in such terrain. It seems, for infrared imagery to be effective, ideal conditions must exist. The study by Ditchkoff et al. (2005) in South Carolina may have benefited from high deer densities in an ideal setting with a forest canopy minimizing false-positives and -negatives and enough tracts of recently burned forest so that the understory vegetation did not significantly affect detection rates. Given the proper conditions, infrared thermal imagery may be an excellent technique for finding and capturing neonates, but, in conditions other than these, it can be a costly mistake. Thermal infrared imaging equipment is expensive, with prices ranging from US$6,000 to upwards of $40,000 (Ditchkoff et al. 2005). We recommend wildlife professionals assess the conditions under which thermal imaging may be used before purchasing a thermal infrared imaging camera.
Citation:Butler, D. A., W. B. Ballard, S. P. Haskell, and M. C. Wallace. 2006. Limitations of thermal infrared imaging for locating neonatal deer in semiarid shrub communities. Wildlife Society Bulletin 34:1458-1462.

Title:Texas tortoise (Gopherus berlandieri) consumed by a mountain lion (Puma concolor) in southern Texas
Journal/Year:The Southwestern Naturalist/2006
View:Download Adams_etal_2006_TortoiseMountainLion.pdf
Author(s):R. Bill Adams|James C. Pitman|Louis A. Harveson
Abstract:Mountain lions (Puma concolor), throughout their distribution, eat a variety of prey, but primarily consume large prey (e.g., cervids). While monitoring radio-collared mountain lions, we saw a mountain lion kitten consuming a Texas tortoise (Gopherus berlandieri). Small prey might increase survival of young mountain lions developing predation skills required for solitary survival as adults.
Management Implications:Texas tortoises are listed as threatened by the State of Texas, but Hellgren et al. (2000) reported a density of 0.26 tortoises/ha in southern Texas. Hellgren et al. (2000) suggested that the Texas tortoise population could withstand predation by coyotes (Canis latrans), raccoons (Procyon lotor), crested caracaras (Polyborus plancus), and other predators. Logan and Sweaner (2001:305-306) reported turtle remains in 1 of 832 scats examined in southern New Mexico. Additionally, Harveson et al. (2000) found no tortoise remains from 25 mountain lion scats, so there is no indication that mountain lions negatively impact the tortoise population in southern Texas. Small prey items, such as the Texas tortoise, are relatively abundant and might increase survival of juvenile mountain lions still developing predation skills required for solitary survival as an adult.
Citation:Adams, R. B., J. Pitman, and L. A. Harveson. 2006. Texas tortoise (Gopherus berlandieri) consumed by a mountain lion (Puma concolor) in southern Texas. The Southwestern Naturalist 51:586-587.

Title:Ecology of sympatric deer species in west-central Texas: methodology, reproductive biology, and mortality and antipredator strageties of adult females and fawns
View:Download Haskell_2007_SympatricDeer.pdf
Author(s):Shawn Patrick Haskell
Citation:Haskell, S. P. 2007. Ecology of sympatric deer species in west-central Texas: methodology, reproductive biology, and mortality and antipredator strategies of adult females and fawns. Dissertation, Texas Tech University, Lubbock, USA.

Title:Food habits of the American badger (Taxidea taxus) in southern Texas: an observation
Journal/Year:The Texas Journal of Agriculture and Natural Resource/2007
View:Download Collins_etal_2007_BadgerFoodHabits.pdf
Author(s):Daniel P. Collins|Louis A. Harveson|Donald C. Ruthven
Keywords:American badger|Taxidea taxus|southern Texas|food habits
Abstract:Limited information exists on American badgers (Taxidea taxus) within their southern distribution. Our goal was to gather information on diet of badgers in southern Texas. We collected 6 badgers from private ranches and road sides in 2 counties (Dimmitt and Duval). Percent content of food items was calculated for each sample. Prickly pear (Opuntia spp.), mesquite (Prosopis glandulosa) bean pods, and rodent remains were found in 4 of the 6 samples collected. Although sample size was small we feel this information provides a good foundation for future research done on this cryptic mammal.
Citation:Collins, D. P., L. A. Harveson, and D. C. Ruthven. 2007. Food habits of the American badger (Taxidea taxus) in southern Texas: an observation. The Texas Journal of Agriculture and Natural Resource 20:28-31.

Title:Observations on capturing and aging deer fawns
Journal/Year:Journal of Mammalogy/2007
View:Visit BioOne - Observations on capturing and aging deer fawns
Author(s):Shawn P. Haskell|Warren B. Ballard|David A. Butler|Nicole M. Tatman|Mark C. Wallace|Christopher O. Kochanny|Ole J. Alcumbrac
Keywords:aging|birth sites|capture|fawns|mule deer|new hoof growth|Odocoileus|Texas|vaginal-implant transmitters|white-tailed deer
Abstract:During a study of fawn mortality of sympatric white-tailed (Odocoileus virginianus) and mule deer (O. hemionus eremicus) in west-central Texas from 2004 to 2006, we made observations that should help deer researchers increase their efficiency of capture of fawns, obtain better estimates of ages of fawns, and obtain more reliable estimates of fawn survival. We experimented with vaginal-implant transmitter designs and found that larger holding wings and antennas protruding < 1 cm past the vulva resulted in more successful drops at birth sites. White-tailed fawns moved farther from birth sites than mule deer fawns of similar ages (P = 0.027). Our model predicted that white-tailed and mule deer fawns moved an average of 100 m away from birth sites after 12.5 and 17.5 h postpartum, respectively; outliers may be expected. Compared to previously published models estimating ages of captive fawns from new hoof growth, our model predicted that free-ranging fawns were generally 1.5 weeks older. As others have suggested, abandonment induced by marking was rare, and we suggest methods for monitoring does and fawns that could minimize such occurrences. Behavioral and morphological models that we describe may be species-, site-, and time-specific, and biologists should use caution when extrapolating inferences from captive animal-derived models to free-ranging populations.
Management Implications:These observations on capturing and aging deer fawns should help researchers contemplating or engaged in studies of fawn survival to execute successful operations and obtain sufficient reliable data. If applied properly, technological advances have potential to further our understanding of reproductive biology and juvenile mortality patterns and recruitment in wild ungulates. We caution against general use of models derived from captive deer to extrapolate inferences to free-ranging populations.
Citation:Haskell, S. P., W. B. Ballard, D. A. Butler, N. M. Tatman, M. C. Wallace, C. O. Kochanny, and O. J. Alcumbrac. 2007. Observations on capturing and aging deer fawns. Journal of Mammalogy 88:1482-1487.

Title:Factors affecting birth dates of sympatric deer in west-central Texas
Journal/Year:Journal of Mammalogy/2008
View:Visit BioOne - Factors affecting birth dates of sympatric deer in west-central Texas
Author(s):Shawn P. Haskell|Warren B. Ballard|David A. Butler|Mark C. Wallace|Thomas R. Stephenson|Ole J. Alcumbrac|Mary H. Humphrey
Keywords:accelerated failure-time|birthing|individuals|Odocoileus|overgrazing|population|proximate factors|rain|sympatry|Texas
Abstract:During a study of fawn mortality, we investigated proximate factors affecting birth dates of sympatric desert mule deer (Odocoileus hemionus eremicus) and white-tailed deer (O. virginianus texanus) in west-central Texas from 2004 to 2006. We treated this aspect of the study as time-to-event survival (i.e., pregnancy to birth) and modeled the process with accelerated failure-time regression. Our best model included effects from 3 hierarchal levels: within-year variation among individuals within species, because older and heavier females gave birth earlier; among-year variation at the population level, because greater rain during the previous prerut and rut periods resulted in earlier birth dates; and a chronic-cohort effect also at the population level, because even after previous effects were accounted for in regression models, deer gave birth later on more intensely grazed ranches. After accounting for mass, age of females as a significant predictor may have indicated a behavioral phenomenon associated with social dominance. We did not find meaningful relationships between birth dates and either offspring sex or rain during gestation. Overall, Kaplan-Meier product-limit estimates indicated that birthing by white-tailed deer peaked on 20 June (90% range = 31 days) and birthing by mule deer peaked on 21 July (90% range = 45 days). We suggest that the 1-month separation between peak birth dates and breeding periods of these sympatric species of deer was partly due to phylogenetic constraint from parent populations and not localized adaptation with selection against hybridization. Prevention of genetic introgression may be a result by coincidence.
Management Implications:Land-use practices that alter behavior and patterns of resource use by wildlife may or may not affect population parameters (Cronin et al. 1998; Mallord et al. 2007). On average, deer on the northern ranches gave birth earlier than those on the southern ranches (Fig. 3; Tables 1 and 2). After accounting for individual- and population-level variability within and among years (Table 2), this remaining effect may be related to more intensive grazing on the southern ranches. Digestibility of forage plants used by white-tailed deer was lower on grazed plots compared to ungrazed plots except in summer (Thill et al. 1987), and intergenerational or cohort effects are known (Gaillard et al. 2000, 2003; Garroway and Broders 2005; Guilhelm et al. 2002; Hewison et al. 2005; Mech et al. 1991). Also, contiguous deer populations have previously demonstrated different demographics due to localized relationships to vegetative carrying capacities (Dapson et al. 1979). Others have suggested that reduced deer and livestock densities can shift peak breeding to an earlier date (Demarais et al. 2000). With different land-use practices (i.e., grazing pressure) on neighboring properties that are substantially larger than the home ranges of deer, it is plausible that demographics could differ across a fence-line (Fig. 1D). It is not known if vital rates such as production and survival of fawns were also altered by these land-use differences (e.g., Hailey et al. 1966; McMahan 1964; McMahan and Ramsey 1965; Taylor and Hahn 1947), or if by adjusting breeding and birthing dates, the deer have adequately compensated for chronic poorer nutrition in this mild-winter environment; we will investigate this further in the future.
Citation:Haskell, S. P., W. B. Ballard, D. A. Butler, M. C. Wallace, T. R. Stephenson, O. J. Alcumbrac, and M. H. Humphrey. 2008. Factors affecting birth rates of sympatric deer in west-central Texas. Journal of Mammalogy 89:448-458.

Title:Stakeholders' attitudes concerning black bears in north east Texas: a comprehensive management implication study
Journal/Year:TPWD Report/2008
View:Download Keul_etal_2008_BlackBearAttitudes.pdf
Author(s):Adam Keul|Pat Stephens Williams|Ray Darville|Chris Comer|Mike Legg
Management Implications:Upon total analysis of the data, several recommendations can be made with respect to the future of the black bear in Northeast Texas. The survey data reveals that although the people of the region are generally in favor of having black bears, they do not believe that proactive steps should be taken to bring them to the area. Since the bear will and has naturally re-migrated to the area, efforts should be focused on education and awareness, especially to children and those who spend a significant amount of time outdoors either as an occupation or hobby. It is likely that education and awareness about the myths and realities of living with bears will ease the inevitable transition of Northeast Texas into "bear country". The research can be extended or intensified in a variety of directions. First, it may be necessary to fill the gaps in the data along the lines of under-represented groups. Women, minorities and younger adults were statistically under-represented, and could be polled using a similar targeted survey or methodology. Also, it would be pertinent to compare the results from this survey to other wildlife surveys in East Texas, or from other parts of Texas. An urban survey of bear-opinions might show a rift between the two socio-geographic realms. In addition, using similar surveys of Northeast and Southeast Texas for reference could help define these regions, or even determine if they are significantly different. To further investigate the impact of opinions on this project, more public meetings, or small discussion panels could meet in those regions affected to elicit detailed information. It seems that a gathering of minds and speaking one-on-one with the stakeholders could give researchers a better representation of local opinions. Moreover, determining the cause of the low response rate would also be a worthwhile endeavor. At this point, it is not known whether non-response was a showing of disapproval for black bears, or a lack of interest in returning unsolicited mail. Although the handwritten comments (including letters) seemed to indicate disdain towards surveys and non-response based on lack of knowledge, a more scientific study of non-response is necessary. To determine this, a random selection of non-respondents should be polled for their reasons for non-response. In addition, it is recommended that future research studies be conducted to look at stakeholders in the adjacent states who have a history of existing bear populations to determine the perceptions concerning living with bears, desired information and education needs, and where they obtain their information, in order to prepare Texans for living with bears; to interview those stakeholders in Texas that have reported bear sightings to determine the differences in attitudes from those who have not had bear encounters; and to do in-depth I and E in those areas identified by this study as "hot" spots of potential fear and non-acceptance.
Citation:Keul, A., P. Stephens Williams, R. Darville, C. Comer, and M. Legg. 2008. Stakeholders' attitudes concerning black bears in northeast Texas: a comprehensive management implication study. Texas Parks and Wildlife Department Technical Report, Austin, USA.

Title:Association of black-tailed prairie dogs (Cynomys ludovicianus) with playa lakes and a new approach to estimating size of populations
Journal/Year:The Southwestern Naturalist/2009
View:Download Pruett_etal_2009_PrairieDogPlayas.pdf
Author(s):Alison L. Pruett|Clint W. Boal|Mark C. Wallace|Heather A. Whitlaw|James D. Ray
Abstract:We studied 403 colonies of black-tailed prairie dogs (Cynomys ludovicianus) in a 28,927-km2, 12-county area of the southern High Plains, and we examined the distribution, area of colonies, size of populations, and association of these colonies with playa lakes. We used visual counts and estimated size of populations based on modeling of the proportion of a population of prairie dogs above ground at the times of surveys. Colonies in the southern High Plains were small (median = 8.8 ha), with generally small populations (median = 68), and average densities of 14 ± 22 prairie dogs/ha. Colonies were closer to playa lakes than would be expected by chance (P < 0.001), with 40% of colonies built in the basin, slopes, or both, of playa lakes compared to only 3% of 1,000 random points. The association of prairie dogs with playa lakes in the heavily cultivated area of the southern High Plains suggests that playas are a major portion of the habitat of black-tailed prairie dogs in the region.
Management Implications:Individual visual counts cannot be used to estimate size of population in a colony with reliability. Trials consisting of 1-2 counts lacked accuracy, whereas trials with 3-5 counts did not differ statistically. Our estimates of size of population derived from this modeling approach are likely biased low, but we believe our method provides a more accurate, and logistically and financially feasible, approach to estimation of size of population than others that are used currently. However, we have tested our method in our study area only. While this approach should be applicable elsewhere, models likely will need to be refined to local conditions, such as latitudinal differences in length of day and range of temperature. Land-use practices and efforts to reduce populations of prairie dogs appear to be the most relevant factors in current location of colonies in the southern High Plains. Prairie dogs here are closely associated with playa lakes because they are the few areas that have not undergone substantive alteration to crop or livestock production. This presents an excellent opportunity for conservation efforts through landowner-incentive programs; many landowners already are disinclined to alter playa lakes due to periodic flooding. Although playa lakes already are important for conservation of prairie dogs in the southern High Plains of Texas, if land conversion to agriculture continues throughout the region, playas may become the only areas available to prairie dogs regardless of management decisions.
Citation:Pruett, A. L., C. W. Boal, M. C. Wallace, H. A. Whitlaw, and J. D. Ray. 2009. Association of black-tailed prairie dogs (Cynomys ludovicianus) with playa lakes and a new approach to estimating size of populations. The Southwestern Naturalist 54:19-23.

Title:Determining observer reliability in counts of river otter tracks
Journal/Year:Journal of Wildlife Management/2009
View:Visit Wiley Online Library - Determining observer reliability in counts of river otter tracks
Author(s):Jonah W. Evans|Ciel A. Evans|Jane M. Packard|Gary Calkins|Mark Elbroch
Keywords:behavior|indirect signs|Lontra canadensis|Lutra|observer reliability|river otter|Texas|tracks
Abstract:In many research projects, reliability of collected data is dependent on reliability of field observers. However, it is uncommon for observer reliability to be either measured or reported in wildlife research. We tested whether observer skill affected outcomes of a northern river otter (Lontra Canadensis) track survey conducted by the Texas Parks and Wildlife Department. Observers recorded presence of tracks at bridge sites (n = 250) throughout a 27-county region in east Texas, USA. Logistic regression indicated that observers were significantly associated with frequency of reported otter tracks. Because observers were not assigned to bridges at random, we tested and found associations between the bridges surveyed by each observer (SURVEY ROUTE) and habitat variables (WATERSHED, VEGETATION-TYPE, WATER-TYPE, BRIDGE-AREA) that may have influenced otter presence and probability of detection. A standardized tracker evaluation procedure indicated that experienced observers (n=7) misidentified 37% of otter tracks. Additionally, 26% of tracks from species determined to be "otter-like" were misidentified as otter tracks. We recommend that observer skill in identification of animal tracks and other indirect signs be measured to detect and reduce observer errors in wildlife monitoring.
Management Implications:Many wildlife studies would benefit greatly from adopting standardized methods of evaluating skills of field biologists and data collectors. Methods such as the track and sign evaluation we used could be applied to a variety of research fields, both for testing validity of preexisting data and for quantitatively evaluating skills of field observers.
Citation:Evans, J. W., C. A. Evans, J. M. Packard, G. Calkins, and M. Elbroch. 2009. Determining observer reliability in counts of river otter tracks. Journal of Wildlife Management 73:426-432.

Title:Differences in timing of parturition, birthing sites, and bedding sites of fawns in sympatric populations of deer
Journal/Year:The Southwestern Naturalist/2009
View:Download Butler_etal_2009_FawnBirthSites.pdf
Author(s):David A. Butler|Shawn P. Haskell|Warren B. Ballard|Mark C. Wallace|Carlton M. Britton|Mary H. Humphreys
Abstract:Mule deer (Odocoileus hemionus) have been declining throughout the western United States and white-tailed deer (O. virginianus) have remained stable or increased. In areas of sympatry, it is important to understand dynamics between the two species. Crockett County, Texas, provided an area where the two species occurred sympatrically at relatively high densities. In summers 2004-2005, we captured adult deer and fitted them with radiocollars and vaginal-implant transmitters. We monitored vaginal-implant transmitters to record date of parturition, to locate birth sites, and to aid in capture of neonates. We captured 101 neonates (68 mule deer and 33 white-tailed deer). We observed 45 parturition sites and 249 day-time bedding sites of fawns. Parturition in mule deer began ca. 1 month after white-tailed deer. Birth sites of mule deer were at higher elevations and on steeper slopes than those of white-tailed deer. Mule deer gave birth under junipers (Juniperus) more often than did white-tailed deer. Our best model used elevation, height of horizontal hiding cover, type of vegetation, canopy shrub, and an interaction between vegetation type and canopy shrub to differentiate between bedding sites of fawns of mule deer and white-tailed deer. Fawns of mule deer bedded at higher elevations in shorter hiding cover and commonly under junipers, whereas fawns of white-tailed deer commonly bedded under honey mesquite (Prosopis glandulosa) or in herbaceous vegetation. Our data show that fawns partition habitat in a manner similar to adults in this area.
Management Implications:Fawns of mule deer and white-tailed deer used habitat differently. Fawns appear to partition habitat in the same manner as adults. Our data for parturition sites of adults show similar differences between adult females as do our bedding sites for fawns. Both fawns and adult mule deer used higher elevations, canopy of junipers, and open vegetation (e.g., mixed junipers and yuccas). Previous studies on our study site also determined that adults partitioned habitat on the basis of elevation, slope, type of vegetation, and cover of shrubs (Avey, 2001; Avey et al., 2003; Brunjes, 2004). Avey (2001) reported that adult mule deer used steeper slopes, less shrub cover, and greater forb cover than white-tailed deer. Brunjes (2004) focused on a broader scale to reveal that mule deer used vegetation associated with junipers, steeper slopes, and higher elevations. White-tailed deer used vegetation that had mesquites and were denser than those used by adult mule deer. Our study demonstrates that junipers and mesquites (often considered undesirable shrubs) are important to habitat of mule deer and white-tailed deer. Land managers should consider this during range management. Although our study does not provide an answer to the proper amount of shrubs needed (there are upper and lower bounds), it is clear that complete removal of junipers and mesquites would not benefit populations of deer.
Citation:Butler, D. A., S. P. Haskell, W. B. Ballard, M. C. Wallace, C. M. Britton, and M. H. Humphreys. 2009. Differences in timing of parturition, birthing sites, and bedding sites of fawns in sympatric populations of deer. The Southwestern Naturalist 54:261-271.

Title:Effects of summer and winter burning on vegetation and wildlife in a sand sagebrush/honey mesquite savanna
View:Download Poole_etal_2009_BurningVegetation.pdf
Author(s):Matthew W. Poole
Abstract:There is substantial information on the generalized effects of fire in some grassland ecosystems. However, studies addressing seasonality of fire are less common. The Rolling Plains have high climatic variability with periodic droughts; however, little information is available on the potential role of burning in these communities under these conditions. Therefore, I initiated a project to explore the effects of seasonality of fire on a sand prairie ecosystem. We established 5 blocks of 3 18-ha plots at Matador Wildlife Management Area (WMA) in Cottle County, Texas. Each plot, within a block, was randomly assigned to a summer burn (August), winter burn (February), or a control (no fire) treatment. Herbaceous vegetation cover and frequency were measured twice annually (May-June and August-September) using 0.1 m² quadrats, while woody cover was measured during late summer using the line-intercept method. Invertebrates, herpetofauna, and small mammals were sampled utilizing drift fence arrays during the spring and summer. Invertebrates were also sampled in late summer using sweep nets and small mammals were also sampled twice annually using Sherman live traps. Summer burning appeared to benefit forbs, species richness, evenness and diversity. In general, forbs were not affected by winter burning, but forbs were similar to grasses, in that individual species' responses to winter burning were variable. My results indicated that prescribed summer burning appears to be effective at reducing, but not eliminating sand sagebrush, honey mesquite, prickly pear, yucca, and total woody canopy cover. Summer burning was the most effective treatment at reducing honey mesquite and sand sagebrush, which may have promoted the observed increases in herbaceous vegetation by making resources, such as light and water, available to grasses and forbs. However, many of the wildlife species examined did not respond to the application of summer and winter burning, but responded to onset of drought conditions. Therefore, a combination of both summer and winter burning treatments are recommended for suppressing woody plant cover and increasing overall plant diversity by promoting desirable herbaceous species for a wide variety of wildlife and livestock. Longer term research on the effects of summer and winter burning on herbaceous and woody vegetation, especially in drought years, is needed to fully evaluate the effects of burning in the Rolling Plains of Texas.
Citation:Poole, M. W. 2009. Effects of summer and winter burning on vegetation and wildlife in a sand sagebrush/honey mesquite savanna. Thesis, West Texas A&M University, Canyon, USA.

Title:Evaluating hunter support for black bear restoration in east Texas
Journal/Year:Human Dimensions of Wildlife/2009
View:This is an electronic version of an article published in Human Dimensions of Wildlife© 2009 Copyright Taylor and Francis; This article is available online at Taylor & Francis Online - Evaluating hunter support for black bear restoration in east Texas
Author(s):Anita T. Morzillo|Angela G. Mertig|Nathan Garner|Jianguo Liu
Keywords:attitudes|black bear|hunting|restoration|Texas
Abstract:Hunters are an influential interest group in wildlife management. Little is known, however, about variation in attitudes toward species restoration among hunters in regard to either specific hunting interests or restoration of black bear. We surveyed 1,006 East Texas residents to assess hunter support for restoration of black bear populations in East Texas and hunter interest in hunting black bears. Because we defined hunters broadly, our study included hunters who were demographically dissimilar to those in other studies. Sixty-one percent of hunters supported black bear restoration. Among hunters, restoration support was twice as great among those interested versus not interested in hunting black bears. Our results highlight the importance of measurement differences in determining the boundaries of particular stakeholder groups and reinforce the importance of hunting specialization in influencing management attitudes.
Citation:Morzillo, A. T., A. G. Mertig, N. Garner, and J. Liu. 2009. Evaluating hunter support for black bear restoration in east Texas. Human Dimensions of Wildlife 14:407-418.

Title:Activity patterns of two sympatric species of skunks (Mephitis mephitis and Spilogale gracilis) in Texas
Journal/Year:The Southwestern Naturalist/2010
View:Download Neiswenter_etal_2010_SkunkActivity.pdf
Author(s):Sean A. Neiswenter|Robert C. Dowler|John H. Young
Abstract:We used radiotelemetry to document and compare activity and movement between the western spotted skunk Spilogale gracilis, and the striped skunk Mephitis mephitis in Texas. Mephitis mephitis had a higher rate of movement than S. gracilis. Both species had highest rates of movement during autumn, coinciding with dispersal of young. With the exception of summer, M. mephitis was significantly more active than S. gracilis and generally took shorter breaks during nightly activity. We documented statistical differences in activity between species for all seasons. Highest activity of one species occurred during lowest activity of the other species, which may indicate avoidance of the larger more-dominant species, M. mephitis, by S. gracilis.
Management Implications:These data add to the growing literature on behavior and natural history of skunks. Understanding movements and activity patterns is an important step toward developing a proper management plan for these species. These data may also be useful in understanding temporal cycles of disease transmission, specifically rabies, in skunks. For example, in autumn, skunks generally are more active and move farther each night, which may make them more prone to transmission of disease through direct contact. In turn, increased activity may increase the likelihood of humans and domestic animals being exposed to diseased skunks. Finally, we hypothesize that subtle changes in temporal activity in conjunction with different microhabitats allow these two similar species to co-exist. In westcentral Texas, there are three species of skunks, as well as several other mesocarnivores, including raccoons (Procyon lotor), ringtails (Bassariscus astutus), and Virginia opossums (Didelphis virginiana), that occur sympatrically. This area offers future opportunities to examine how patterns of temporal activity and use of space differ among organisms with different feeding ecologies and different levels of phylogenetic relatedness.
Citation:Neiswenter, S. A., R. C. Dowler, and J. H. Young. 2010. Activity patterns of two sympatric species of skunks (Mephitis mephitis and Spilogale gracilis) in Texas. The Southwestern Naturalist 55:16-21.

Title:Assessment of current status of black bear populations in east Texas using hair snares and genetic mark-recapture analysis
Journal/Year:TPWD Final Report/2010
View:Download Comer_Siegmund_2010_BlackBearPop.pdf
Author(s):Christopher E. Comer|Timothy M. Siegmund
Citation:Comer, C. E., and T. M. Siegmund. 2010. Assessment of current status of black bear populations in east Texas using hair snares and genetic mark-recapture analysis. Texas Parks and Wildlife Department Final Report, Austin, USA.

Title:Genetic variation of pronghorn populations in Texas
View:Download Keleher_2010_Pronghorn.pdf
Author(s):Renee C. Keleher
Abstract:Texas Parks and Wildlife Department (TPWD) established approximately 100 pronghorn herd units in the 1970s using large land holdings, historic habitat conditions, survey data, and suggested movement barriers. Today, these same herd units are the basis of Texas' pronghorn survey and harvest management program. An updated assessment of pronghorn population structure is needed. I sampled 351 pronghorn throughout their distribution in Texas during the 2007-2008 harvest seasons and genotyped 344 pronghorn at 8 microsatellite loci. My goals were to assess geographic patterns of genetic similarity and to investigate the spatial scale of population structure in Texas. I detected moderate levels of genetic diversity within sampled pronghorn populations, and a small but significant level of genetic structure among populations (FST = 0.034). Bayesian analyses of population structure revealed that sampled populations could be clustered into 2 groups and a weak correlation (r2 = 0.024) between genetic distance and geographic distance among populations. I concluded that population structure in Texas is not strongly differentiated. This may suggest that either gene flow is occurring among and within populations, historical genetic structure is still being detected, or previous pronghorn translocations has affected the genetic structure of pronghorn populations in Texas. Future research should involve more molecular markers, and increased sample sizes from the Panhandle and Rocker b populations. Overall, information from this project can aid TPWD in delineating pronghorn metaherd units and may assist in future trap, transport, and translocation projects in Texas.
Management Implications:My analyses indicate that natural movements are occurring between some populations in the Trans-Pecos and Panhandle regions. The analyses also support successful population restocking efforts. There is no firm evidence for isolated populations; but Herd Unit 40, Marathon Basin, and the Rocker b ranch are peripheral in pronghorn distribution in their regions and should be monitored with survey data for isolation trends in the future. Further, the effects of movement barriers on population structure may not be detectable for several generations. A follow up analyses of pronghorn population structure in Texas is warranted. Pronghorn management should continue to be aimed at preserving natural movements among sites. Fence modifications, construction of wildlife highway crossings, and limiting urban development in key travel corridors are recommended to facilitate pronghorn movements. Attention should be given to the supporting evidence of gene flow occurring between populations north and south of Highway 90. If pronghorn are crossing highways (e.g. direct observations and road kills), cooperation between the Department of Transportation and the Texas Parks and Wildlife Department should identify and protect major crossing zones through road signs and fence structures. Brush encroachment, urbanization, heavy livestock stocking rates, drought, predation, and agriculture could influence or restrict pronghorn movements, and may be detrimental for the recolonization of favorable habitat. A pronghorn habitat management priority should be one that that promotes healthy grasslands. It does not appear that future translocations within Hudspeth and Culberson counties or within the Panhandle will disrupt unique genetic signatures of populations. Translocations between some of the Panhandle populations and some of the Trans-Pecos populations could also be an option for future population restorations, if necessary. Consideration should be given to mixing individuals from different clusters within the Trans-Pecos region (e.g. Hudspeth/Culberson counties and North/South HWY 90) in order to protect genetic characteristics unique to those populations.
Citation:Keleher, R. C. 2010. Genetic variation of pronghorn populations in Texas. Thesis, Sul Ross State University, Alpine, TX, USA.

Title:Postpartum group cohesion of sympatric deer in Texas
Journal/Year:Journal of Wildlife Management/2010
View:Visit Wiley Online Library - Postpartum group cohesion of sympatric deer in Texas
Author(s):Shawn P. Haskell|Warren B. Ballard|Mark C. Wallace|Mary H. Humphrey|David A. Butler
Keywords:behavior|bobcat|fawns|mule deer|Odocoileus hemionus eremicus|O. virginianus|postpartum|predation|Texas|white-tailed deer
Abstract:Postpartum behavior of maternal deer may be specific to species of deer and predators. We captured sympatric white-tailed deer (Odocoileus virginianus) and mule deer (O. hemionus eremicus) fawns from radiocollared adult females in 2004-2006 on rangelands of west central Texas, USA, where predators larger than bobcats (Lynx rufus) were absent. Our objective was to determine whether differences in postpartum antipredator behavior existed between deer species, and if so, examine efficacy of those strategies. We collected postpartum group cohesion data in 2004 and 2005 by using radiotelemetry and examined dead fawns for cause of mortality. During fawns' hider phase, < 3 weeks postpartum, mule deer females kept fawns closer to themselves (95% CI = 39-66 m) and twins closer to each other (95% CI = 25-49 m) than did white-tailed deer females (95% CIs = 152-234 m and 163-255 m, respectively). After 30 days postpartum, familial group cohesion was similarly tight for both species. During hider phases from 2004 to 2006, predated carcasses of white-tailed deer fawns (11 of 11) were dismembered or consumed more than mule deer fawns (7 of 13, P = 0.016), which was one line of evidence for maternal defense by mule deer adults. During hider phases in 2004 and 2005, predation rate of mule deer fawns was lower than that for white-tailed deer fawns. In 2006, predation rate increased for mule deer but was similar for white-tailed deer fawns compared with previous years. The tight cohesion strategy of mule deer exhibited in 2004 and 2005 seemed successful at thwarting small predators. Without large predators, the loose cohesion strategy of white-tailed deer females was maladaptive. When meso-predators are abundant due to extermination of larger predators, predation on fawns could increase if a deer species has relatively fixed postpartum maternal antipredator behavior.
Management Implications:It may be important to understand ramifications of maternal antipredator behavior if reduction of larger predators releases populations of smaller meso-predators as was demonstrated in western Texas (Henke and Bryant 1999). The loose cohesion strategy of white-tailed deer was maladaptive without large predators; this behavior may be the result of a relatively long evolutionary history with many large predators. If objectives are to increase fawn survival, then drastic reduction of large predators may have undesirable results if populations of meso-predators are numerically released and the deer species exhibits innately fixed loose-cohesion maternal-antipredator behavior, such as in white-tailed deer and roe deer.
Citation:Haskell, S. P., W. B. Ballard, M. C. Wallace, M. H. Humphrey, and D. A. Butler. 20010. Postpartum group cohesion of sympatric deer in west-central Texas. Journal of Wildlife Management 74:1686-1692.

Title:Small mammals associated with colonies of black-tailed prairie dogs (Cynomys ludovicianus) in the southern High Plains
Journal/Year:The Southwestern Naturalist/2010
View:Download Pruett_etal_2010_SmallMammalsPrairieDogColonies.pdf
Author(s):Alison L. Pruett|Clint W. Boal|Mark C. Wallace|Heather A. Whitlaw|James D. Ray
Abstract:We compared diversity and abundance of small mammals at colonies of black-tailed prairie dogs (Cynomys ludovicianus) and paired non-colony sites. Of colonies of black-tailed prairie dogs in our study area, >80% were on slopes of playa lakes; thus, we used sites of colonies and non-colonies that were on slopes of playa lakes. We trapped small mammals on 29 pairs of sites. Overall abundance did not differ between types of sites, but some taxa exhibited associations with colonies (Onychomys leucogaster) or non-colonies (Chaetodipus hispidus, Reithrodontomys, Sigmodon hispidus). Diversity and evenness of small mammals did not differ between colonies and non-colonies in 2002, but were higher on non-colonies in 2003. Although we may not have detected some rare or infrequently occurring species, our data reveal differences in diversity and evenness of more common species among the types of sites. Prairie dogs are touted as a keystone species with their colonies associated with a greater faunal diversity than adjacent lands. Our findings contradict several studies reporting greater diversity and abundance of small mammals at colonies of prairie dogs. We suggest that additional research across a wider landscape and incorporating landscape variables beyond the immediate trapping plot may further elucidate interspecific associations between black-tailed prairie dogs and species of small rodents.
Management Implications:Black-tailed prairie dogs frequently are cited as a keystone species in grasslands and prairies (Kotliar et al., 1999; Miller et al., 2000), but there have been contradictory views (e.g., Stapp, 1998). Our report is not an entry into that debate, but presentation of data on associations and dissociations between black-tailed prairie dogs and small rodents at the ecologically rich areas of playa lakes (Haukos and Smith, 1992; Smith, 2003). The only positive association we detected between prairie dogs and small rodents was with O. leucogaster. We determined that prairie dogs may have a negative influence on some small mammals such as C. hispidus, Reithrodontomys, and S. hispidus. Our data are not consistent with several other studies suggesting diversity and abundance of small mammals is greater in colonies of prairie dogs. We suggest that additional research across a wider landscape and incorporating landscape variables beyond the immediate trapping plot may further elucidate interspecific associations between black-tailed prairie dogs and small rodents. However, we reiterate that our study focused on a relatively narrow range of associations between prairie dogs and small rodents, not prairie dogs and the range of flora and fauna that they may influence.
Citation:Pruett, A. L., C. W. Boal, M. C. Wallace, H. A. Whitlaw, and J. D. Ray. 2010. Small mammals associated with colonies of black-tailed prairie dogs (Cynomys ludovicianus) in the southern High Plains. The Southwestern Naturalist 55:50-56.

Title:Socioeconomic factors affecting local support for black bear recovery strategies
Journal/Year:Environmental Management/2010
View:Visit Springer Link - Socioeconomic factors affecting local support for black bear recovery strategies
Author(s):Anita T. Morzillo|Angela G. Mertig|Jeffrey W. Hollister|Nathan Garner|Jianguo Liu
Keywords:American black bear|attitudes|conditional probability analysis|human-bear conflict|human dimensions|population recovery|Ursus americanus|wildlife management
Abstract:There is global interest in recovering locally extirpated carnivore species. Successful efforts to recover Louisiana black bear in Louisiana have prompted interest in recovery throughout the species' historical range. We evaluated support for three potential black bear recovery strategies prior to public release of a black bear conservation and management plan for eastern Texas, United States. Data were collected from 1,006 residents living in proximity to potential recovery locations, particularly Big Thicket National Preserve. In addition to traditional logistic regression analysis, we used conditional probability analysis to statistically and visually evaluate probabilities of public support for potential black bear recovery strategies based on socioeconomic factors. Allowing black bears to repopulate the region on their own (i.e., without active reintroduction) was the recovery strategy with the greatest probability of acceptance. Recovery strategy acceptance was influenced by many socioeconomic factors. Although impact was limited, older and long-time local residents were most likely to want to exclude black bears from the area. Concern about the problems that black bears may cause was the only variable significantly related to support or non-support across all strategies. Lack of personal knowledge about black bears was the most frequent reason for uncertainty about preferred strategy. In order to reduce local uncertainty about possible recovery strategies, we suggest that wildlife managers focus outreach efforts on providing local residents with information pertinent to minimizing the potential for black bear-human conflict.
Management Implications:Our results provide managers with baseline information about recovery support, concerns, and uncertainty that may be used for further public outreach efforts. Complementing logistic analysis with visually friendly CPA may be more useful than statistical output alone, particularly when presenting results to the general public. For instance, outreach emphasis on providing even a small amount of information about black bears may be effective at helping residents make informed decisions about management actions and future black bear recovery policy (McFarlane and other 2006). However, there is no guarantee that outreach and related information will results in either increased local knowledge about black bears (Bowman and other 2001) or greater support for recovery (Bright and Manfredo 1995; Lohr and others 1996; see also Morzillo and others 2007a). Some residents never will support recovery, but learning more about and conditions that determine locals' reasons for opposition or uncertainty may prove valuable for conservation planning.
Citation:Morzillo, A. T., A. G. Mertig, J. W. Hollister, N. Garner, and J. Liu. 2010. Socioeconomic factors affecting local support for black bear recovery strategies. Environmental Management 45:1299-1311.

Title:A sightability model for aerial surveys of mule deer in Western Texas
View:Download Zabransky_2011_MuleDeer.pdf
Author(s):Cody James Zabransky
Abstract:Aerial surveys are used to assess mule deer (Odocoileus hemionus) populations, but are biased because not all deer are counted. My objectives were to quantify factors affecting visibility of mule deer during helicopter surveys, and develop a sightability model to reduce bias in deer population estimates. I collared 215 deer with GPS collars on 6 sites covering distinct habitats of mule deer range in Texas. I obtained data on group size, vegetation, activity, light, terrain, and distance from transect for deer seen during surveys and deer not seen. I used logistic regression to derive two sightability models, one in which all measured variables were included and one which excluded group size because of difficulty measuring group size of unseen groups. Population size estimated using sightability models averaged 93.1% of the estimates derived using mark-resight techniques. Implementing sightability models will improve data available for mule deer management in Texas. Statistically defensible data concerning population size and composition are necessary for proper management, especially for species such as the mule deer, which has experienced decreases in population size across its range. Raw count and trend data may not be sufficient for management of these species because not all animals are counted and precision is low. The objective of this research is to develop a sightability model for estimating mule deer population size and composition across the mule deer range in Texas. Two hundred fifteen mule deer were collared over 3 years to obtain location information during helicopter surveys and to quantify factors (e.g., percentage of woody cover, vegetation type, deer activity, terrain, light conditions, and distance between deer and path of helicopter) affecting visibility of mule deer during helicopter surveys. Four study areas were in the Trans-Pecos region and 2 were in the Panhandle. These study sites were chosen because they represented large areas of mule deer habitat in Texas and included a broad range of terrain, percentage of woody cover, and vegetation types, which will improve model applicability across the state. Initial analysis suggests that, on average, 48% of mule deer are seen from helicopters, but the percentage of deer seen on any individual survey ranges from 23 to 86%. Therefore, a single correction multiplier is not a reliable method for estimating mule deer populations annually. These data also suggest that uncorrected survey data currently in use are not producing accurate estimates of mule deer populations in Texas.
Management Implications:While sightability models can improve the estimate of a mule deer population, logic and planning are necessary for valid surveys. It is imperative for observers to maintain focus on the survey or biased results are likely. Distractions should be minimized during survey time and those individuals that lack experience flying should take an antiemetic a sufficient time before flying to reduce the chance of air sickness. Those lacking experience should also be placed in the right-rear position in the helicopter. This position requires the observer to scan less area than the left-front position allowing the observer more attention to the survey area. Observers are encouraged to wear light-weight clothing and bring layers for comfort. Dark-colored clothing and sunglasses should also be worn to reduce the impact of light reflection on windows which can impede vision on sunny days. Laser rangefinders should be used by each observer in the helicopter to calibrate distance estimates. While the currently used Bell Jet Ranger has smaller windows with more visual obstruction than the Robinson R44, its ability to climb and travel safely at slow speed make it a desirable aircraft in the mountains of the Trans-Pecos region. Maneuverability and a marked increase in visibility associated with the Robinson R44 Raven II make it desirable in gently rolling terrain. Lower hourly costs make Robinson helicopters appealing for private landowners. The presence of a third passenger to record observations or the use of an audio recording system with GPS technology along with familiarity of observers with codes for data collection increases the time observers can spend looking for animals, and will more closely match conditions under which sightability models were developed. I added the fourth person because extensive data collection during model development could have compromised research objectives by distracting primary observers had they been responsible for data recording. While scheduling pilots may be out of the wildlife department's control, experienced pilots comfortable with low speed, low altitude flying are essential. High altitudes and high speeds may overextend observers' capabilities to search for deer, thus adding bias to counts.
Citation:Zabransky, C. J. 2011. A sightability model for aerial surveys of mule deer in western Texas. Thesis, Texas A&M University-Kingsville, USA.

Title:Assessment of the population status and evaluation of suitable habitats for the Louisiana black bear (Ursus americanus luteolus) in east Texas
View:Download Kaminski_2011_BlackBearThesis.pdf
Author(s):Dan J. Kaminski
Abstract:The Louisiana black bear (Ursus americanus luteolus) historically ranged throughout southeastern Texas, although it was considered extirpated from Texas by the 1940s. In 1987, the black bear was classified as a threatened species in Texas and in 1992, the U.S. Fish and Wildlife Service similarly classified the Louisiana black bear subspecies under the Endangered Species Act. The current distribution of the Louisiana black bear is restricted to portions of eastern Louisiana and western Mississippi, although recent data indicate that these populations are expanding. East Texas contains some of the largest contiguous blocks of forested habitat available to, but currently unoccupied by, black bears in the southeastern U.S. Despite expanding populations in adjacent states, reliable black bear sightings in east Texas, and the presence of potentially suitable black bear habitat throughout the region, quantitative estimates of occupancy and habitat suitability do not exist for east and southeast Texas. We used non-invasive genetic sampling to survey areas of east Texas identified as having the highest likelihood of supporting black bears in the region. We utilized a 2-strand barbed-wire hair trap at 5 study areas totaling 463 km2. We collected 451 hair samples from 181 hair traps from 2009-2011. We eliminated non-bear samples using microscopic sorting techniques and selected 51 samples for genetic analysis. Genetic analysis indicated that no black bears were detected during this study. Considering the effectiveness of the hair trap method in areas of North America with established black bear populations, we concluded that no established population of black bears exist in the south black bear recovery zone; although it is likely that a transient or dispersing bear present in our study areas could remain undetected during our sampling. This study satisfies the research objectives outlined by state and federal Louisiana black bear recovery plans. Baseline occupancy data in east Texas was necessary for directing future recovery efforts and the development of sound restoration and conservation plans. We present the first rigorous assessment of region-wide habitat suitability within the historic distribution of the Louisiana black bear in east and southeast Texas. Because of the large spatial requirements for black bears and the lack of regional habitat information, we developed a landscape-scale habitat suitability index (HSI) model in a geographic information system for evaluating the year-round habitat requirements of black bears. Our model was developed at 10 m resolution and encompassed the 43,553 km2 south black bear recovery zone. We measured hard and soft mast production, understory vegetation density, and tree den availability at 516 survey points in 38 habitat classes (82% of the total land cover) in the region. We developed GIS-based models for summer food productivity, fall food availability, productivity, and diversity, protection cover, tree den availability, distance to roads, and human development. We combined index models and calculated overall HSI scores per pixel in a continuous dataset. Habitat suitability index scores ranged from 0.00-0.76 throughout the region. Our model indicated that highly (< 1%) and moderately (16%) suitable habitat existed in the south recovery zone although the majority of the area (84%) was classified as marginal or unsuitable habitat. We identified 4 recovery units capable of sustaining viable populations of black bears using our model. Recovery units ranged in size from 31,583 to 74,285 ha and from 0.58 to 0.60 in HSI scores. Estimated HSI scores for each recovery unit were comparable to those previously reported for occupied range in the southeastern U.S. and acreage of suitable habitat for all recovery units exceeded those estimated to support existing Louisiana black bear populations. Our model may be used to highlight habitat quality deficiencies related to the year-round habitat requirements for black bears in the south recovery zone of east Texas. Region-wide habitat suitability data was necessary to direct future habitat conservation and improvement programs towards achieving the goals outlined by state and federal Louisiana black bear recovery plans.
Citation:Kaminski, D. J. 2011. Assessment of the population status and evaluation of suitable habitats for the Louisiana black bear (Ursus americanus luteolus) in east Texas. Stephen F. Austin State University, Nacogdoches, TX, USA.

Title:Breeding behavior and secondary sex characteristics of male white-tailed deer in southern Texas
View:Download Foley_2011_MaleWTDDissertation.pdf
Author(s):Aaron M. Foley
Abstract:Environmental variation can influence forage quality and quantity which in turn can affect body condition. Body condition can affect many aspects of white-tailed deer biology, including reproduction and secondary sex characteristics. I studied male mating strategies, female reproductive success, and antler growth in southern Texas, a semi-arid environment with variable rainfall. I captured 106 male white-tailed deer during 2006-2009, and fitted each male with a GPS radio-collar programmed to acquire locations during the rut (November to January). During peak rut, males increased movement rates, remained within home ranges except for brief excursions, and most did not conform to Levy movements. Relative to other rut phases, focal points were re-visited more often, but residency time was shortest. This behavior suggests that males may rely on spatial memory by returning to profitable areas to briefly assess female receptiveness. During drought years, such behavior was less prominent, as males were 67% more likely to remain in close proximity to a single focal point. This may be a strategy to reduce cost associated with poor body conditions during drought years. I used 6 enclosures with supplemental nutrition and 6 without to determine influence on reproductive success. Young fed males (≤ 2.5 year old) sired 13% offspring while no unfed young males sired offspring. All adult females had high pregnancy rates however; mature females recruited most offspring in fed (76%) and unfed (83%) enclosures. Compared to unfed mature females, fed mature females raised more fawns (49% vs. 23%), raised more twins (31% vs. 9%), and had higher fetal counts (1.85 vs. 1.50). Supplemental nutrition allowed females to increase reproduction but did not substitute for maternal experience. I captured 30 to 150 males annually at 7 southern Texas sites to determine repeatability of antler traits. Repeatability is the intra-class correlation between repeated measures of the same trait. Repeatability was moderate to high (0.42-0.82) for all traits. Repeatability of several traits from variable rainfall sites was lower than consistent rainfall sites. Sites with variable rainfall had 13-18% higher repeatability when feed was available. The association between repeatability and variable environmental conditions supports the role of antlers as an honest advertisement of individual condition and illustrates the magnitude of environmental influence on antler traits. Collectively, my data improve the understanding of how the environment influences deer biology and ecology in semi-arid rangelands. The extent of environmental influences on deer was quantifiable as the availability of supplemental nutrition resulted in more consistent antler expressions and higher reproductive rates in both males and females. Lastly, the movement data improves our understanding how males search for females in an environment that can influence body condition.
Citation:Foley, A. M. 2011. Breeding behavior and secondary sex characteristics of male white-tailed deer in southern Texas. Dissertation, Texas A&M University-Kingsville, USA.

Title:Comparative analysis of population estimators in a known population of white-tailed deer
Journal/Year:TPWD Report/2011
View:Download Reitz_etal_2011_DeerPopulationEstimators.pdf
Author(s):Ryan L. Reitz|Justin A. Foster|Floyd W. Weckerly
Keywords:abundance|herd composition|known population|Odocoileus virginianus|population estimators|sex ratio|Texas
Abstract:The number of small geographically closed populations of white-tailed deer (Odocoileus virginianus) is increasing, and there is little information on the reliability of population estimators at small spatial scales. We compared informal (spotlight, mobile, Hahn, blind, and helicopter) and formal (infrared-triggered camera, distance sampling) population estimators on a known population of white-tailed deer within a 214 ha game fenced enclosure. Estimated sex ratios and abundance were compared to known values. Precision (% coefficient of variation) and accuracy (% relative bias) of all methods were highly variable within and across years. Precision ranged from 4% (blind survey in the afternoon) to 70% (Hahn) and 11% to 26% for informal and distance sampling estimates respectively. Relative bias ranged from -67% (helicopter) to 42% (spotlight) and -49% (camera) to -11% (camera) for informal and formal estimators respectively. All sex ratio estimates demonstrated bias towards does in August and estimates varied greatly across years in September. It is important that biologists and managers consider the variability inherent with deer abundance and sex ratio estimators in small geographically closed populations. Meeting assumptions in survey design and implementation is critical. Comparing estimates to known values in environmental settings that estimators will be applied is essential.
Management Implications:Many methods are applied in Texas over a variety of environmental settings. The methods we reviewed are used because they are considered practical to implement. Our objective was to determine if any traditionally employed methods provide accurate and precise estimates of population size and sex ratios in a small, closed population of deer. Our findings provide little evidence that practical results will derive from a method that are considered practical to implement. All methods were determined to be biased and imprecise among years; however some methods demonstrated useful attributes. Methods with useful attributes were related to a high cost of many survey hours. Improved precision and accuracy may be attainable using camera data to identify branched-antlered deer and AM blind count data to determine herd composition. The 2 methods combined appear to provide the most reliable population size and herd composition information; however, resource managers should not expect perfection. Stresses in time and resources should also be considered when determining what method(s) to apply. Additionally, harvest data and habitat evaluations should always be integrated into any deer management practice. Lastly, Meeting assumptions in survey design and implementation is critical. Methods that deal explicitly with sighting heterogeneity should provide more reliable estimates. Our strongest recommendation is to compare methods to known values in the environmental conditions that the methods will be used.
Citation:Reitz, R. L. J. A. Foster, and F. W. Weckerly. 2011. Comparative analysis of population estimators in a known population of white-tailed deer. Texas Parks and Wildlife Department Unpublished Manuscript, Austin, USA.

Title:Distribution and habitat requirements of bats in the Pineywoods ecoregion of east Texas, with emphasis on Rafinesque's big-eared bat and southeastern myotis
Journal/Year:TPWD Final Report/2011
View:Download Comer_Steumke_2011_BatsPineywoods.pdf
Author(s):Christopher E. Comer|Leigh A. Steumke
Management Implications:Our results emphasize the importance of quantifying detection probability for surveys of any rare or cryptic species like bats. For a species like Rafinesque's big-eared bat, multiple surveys over time are necessary to determine that a site is unoccupied with any degree of confidence. Surveys of known roost sites (TPWD, unpublished data) or other easily identifiable structures (e.g., bridges, Bennett et al. 2008) result in higher rates of detection, but interpretation of these results for landscape-scale occupancy or distribution is often difficult. Further study or development of survey methods may be necessary to estimate occupancy of Rafinesque's big-eared bat at large spatial scales with reasonable confidence. It appears that our target species occur widely and commonly throughout the study areas that we selected. This is especially true for the southeastern myotis. From a management perspective, our general characterization of appropriate habitat for the target species was apparently accurate. Both species appear to be widespread throughout eastern Texas in areas of appropriate habitat. Based on coarse number of echolocation calls, both species are less abundant than other species such as Seminole (Lasiurus seminolus) and evening bats (Nycticeius humeralis). In particular, Rafinesque's big-eared bats were rarely recorded compared to other species, suggesting that they occurred at low abundance. Abundance of forest bats is notoriously difficult to estimate (Weller 2007), but even coarse abundance estimates would be very useful in defining optimal habitat for this species. Alternatively, expanding study areas to include locations with less apparently suitable habitat and/or no history of occupancy for the target species might provide better insight into the characteristics that determine occupancy. Long term management goals for Rafinesque's big-eared bat and Southeastern Myotis should include preservation of known roosts and areas of mature-overmature bottomland cypress-tupelo swamp. Additionally, preserving younger stands and allowing them to reach these older age classes will potentially improve habitat conditions for these bats. Anthropogenic roost structures (including artificial towers constructed specifically for Rafinesque's Big-eared bats) apparently are playing an important role as maternity roost sites in the region (Mirowsky et al. 2004), but the implications for long term population health are unknown. Particularly in areas with few large tupelo trees, structures known to support maternity colonies should be preserved.
Citation:Comer, C. E., and L. A. Steumke. 2011. Distribution and habitat requirements of bats in the Pineywoods ecoregion of east Texas, with emphasis on Rafinesque's big-eared bat and southeastern myotis. Texas Parks and Wildlife Department Final Report, Austin, USA.

Title:Effects of fire and precipitation on small mammal populations and communities
View:Download Witecha_2011_SmallMammalWildfireThesis.pdf
Author(s):Mark J. Witecha
Abstract:Fire and precipitation drive vegetation structure and composition; changes in vegetation will in turn influence distribution and abundance of small mammals. Precipitation also can interact with fire, aiding in recovery, whereas drought may amplify immediate fire effects and prolong recovery. I examined existing literature to reveal patterns on how both precipitation and fire can influence small mammal populations and communities. I also examined the effects of a wildfire that occurred in March 2008 at the Chaparral Wildlife Management Area in South Texas; precipitation varied greatly before and after fire. To examine individual and interactive effects of fire and precipitation, I established 15 1-ha plots that burned at varying intensities and sampled vegetation and small mammals in March-April and October-November, 2009-2010. Fire affected presence and abundance of small mammals based on habitat and dietary requirements, and precipitation altered fire effects for certain species. Examining interactive effects of disturbances provides a more comprehensive understanding for land managers; compounded effects are likely to become increasingly common with invasion of nonnative species and changes in climate and land-use.
Citation:Witecha, M. J. 2011. Effects of fire and precipitation on small mammal populations and communities. Thesis, Texas A&M University-Kingsville, USA.

Title:Effects of sodium nitrite on feral swine and non-targets
Journal/Year:TPWD Final Report/2011
View:Download Foster_2011_SodiumNitrateSwine.pdf
Author(s):Justin Foster
Abstract:Toxicants have been shown to be an effective control measure for feral pigs. One such toxicant, sodium nitrite, was labeled the "Achilles Heel" of feral pigs because of their unique sensitivity to the substance relative to Australian mammals. In the United States, where no toxicants are labeled for use and where pig populations continue to expand their range and abundance, further research is needed for developing more cost effective control tools. Given the qualities of sodium nitrite (i.e. readily available, inexpensive, existing data regarding effects on mammals, etc.) and a recent application for registry with the United States Environmental Protection Agency, it was prudent to conduct further investigations into the qualities of the toxicant. The objective of this study was to determine relative sensitivities of feral pigs, raccoons, and white-tailed deer. We conducted oral gavage trials at the Kerr Wildlife Management Area, Hunt, Texas. Absorbance coefficients for hemoglobin derivatives were estimated at four wavelengths (535, 585, 594, and 626 nanometers). Median lethal doses were estimated with Up-And-Down procedures and were further assessed with fixed dose trials at 113 mg/kg. Control specimens survived anesthesia and water gavage. Raccoons were more sensitive than pigs or deer with MLD and LD50 values estimated at 50 mg/kg and 58 mg/kg respectively. Raccoons expired more rapidly than pigs or deer with a mean time to death of 42.0 ± 7.2 minutes. Our data indicate that raccoons are more sensitive to sodium nitrite than feral pigs. Conversely, deer were less sensitive than feral pigs. Although pigs are not uniquely sensitive, their sensitivity coupled with a target specific delivery system puts them at low risk of intoxication. We recommend that sodium nitrite continue to be evaluated as a candidate toxicant with emphasis on non-target risk and target specific delivery systems.
Management Implications:In conclusion, our data demonstrate that SN shows promise of reducing the cost of feral swine control in Texas. It is lethal, fast acting (< 180 minutes) and can be delivered solely to pigs. We recommend that research supporting the requirements of the application process for registry as a pig toxicant with USEPA be supported by stakeholders. Because SN is patented for use in pig baits, this effort should be in collaboration with the patent holder and all of their American collaborators (Texas Parks and Wildlife, USDA-Aphis-Wildlife Services, USDA-Aphis-National Wildlife Research Center). This would include small (< 10 acres) and large (>10 acres) scale studies. Research topics and literature reviews should include target specificity of feeders; bait preference by pigs and non-targets; stabilization of active ingredients in bait; environmental effects; secondary consumer (i.e. bioaccumulation); efficacy; and novel control devices and solutions.
Citation:Foster, J. 2011. Effects of sodium nitrite on feral swine and non-targets. Texas Parks and Wildlife Department Final Report, Austin, USA.

Title:Exploring mountain lion ecology in Texas using genetic techniques
View:Download Holbrook_2011_MountainLionThesis.pdf
Author(s):Joseph Dale Holbrook
Abstract:Large, territorial, and highly mobile carnivores such as mountain lions (Puma concolor) are difficult to study. I used genetic tools to address recent population characteristics and temporal changes in Texas mountain lions. My recent sample consisted of 245 individuals sampled from New Mexico, western Texas, and southern Texas during 1985-2010. My historical sample consisted of 69 museum specimens collected from western Texas during 1935-1989, and 34 specimens from southern Texas collected during 1934-1942. My contemporary results indicated that mountain lions in New Mexico (HE = 0.61) and western Texas (HE = 0.58) displayed moderate levels of genetic diversity, whereas estimates for southern Texas were lower (HE = 0.47). These regions also exhibited moderate–high levels of genetic differentiation (New Mexico-western Texas FST = 0.06, New Mexico-southern Texas FST = 0.15, western Texas-southern Texas FST = 0.10). However, I identified long-distance movement across my sampling area. These findings indicate a metapopulation structure, and suggest western and southern Texas represent 2 management units. Populations in New Mexico and western Texas may be important for mountain lion recolonization in the southern U.S. Comparisons including historical samples revealed a ≈ 10-20% decline in genetic diversity for southern Texas over time, while diversity in western Texas has remained stable. Genetic differentiation between western and southern Texas has increased 2.5 times, which is likely due to the temporal changes that have occurred within southern Texas (temporal FST = 0.13) rather than western Texas (temporal FST = 0.02). Effective size estimates indicated a lower historical population size in southern Texas relative to western Texas, and that southern Texas has declined > 50% over time. Effective size in western Texas has remained large and stable. My findings show substantial temporal declines and changes have occurred in southern Texas. Future research exploring reproduction and survival in southern Texas is essential. Management actions such as monitoring and harvest reduction may be needed to ensure the persistence of mountain lions in Texas. Overall, this study emphasizes the importance and utility of applying genetic tools to assist wildlife management and conservation.
Management Implications:My results demonstrate the utility of applying a retrospective genetic approach (Schwartz, Luikart & Waples 2006) to evaluate the demographic history of an elusive carnivore. Although exposed to unlimited hunting and a history of land-use change and persecution mountain lions in western Texas appear to have remained at high and stable levels. The current level of harvest may not have a large negative effect on the population. However, my analyses offer no insight on the consequences of increasing harvest in western Texas, which could easily be realized under current regulations. Additionally, it is possible that genetic connectivity to adjacent populations is assisting the stability I observed in western Texas. Connectivity to proximate populations should be considered when applying habitat or population prescriptions. Future research examining mountain lion survival and movements in western Texas would inform questions regarding harvest mortality and interpopulation connectivity. Given the current information, implementing a monitoring program using indices such as harvest reports (Anderson & Lindzey 2005) with genetic sampling would be prudent for future mountain lion management and conservation in western Texas. Declines have occurred in genetic connectivity, genetic diversity and effective population size for mountain lions in southern Texas. In fact the temporal decline in diversity and current effective size are outside of the ranges suggested for long-term population persistence (Soule et al. 1986). Furthermore, the decline in diversity within southern Texas was 10-20% of the overall decline observed in Florida panthers (Culver et al. 2000); a population that has displayed physical symptoms of inbreeding depression (Roelke, Martenson & O'Brien 1993). Additional loss of diversity may occur through genetic drift if the high mortality and low productivity previously documented (Harveson 1997) are sustained. Management actions may be needed if mountain lions are to be maintained in southern Texas. First, the current population size or trend in southern Texas is unknown. Population monitoring efforts are needed to estimate reproductive rates, survival and population viability without management intervention. Reporting mountain lion harvests in southern Texas would assist monitoring efforts. If current harvest is unsustainable, regulation of harvest may be needed (Young 2009). A harvest management plan would allow managers to focus harvest on areas of potential mountain lion-human conflict, while maintaining survival rates of residents and dispersers at sustainable levels. Unlike the Florida panther, southern Texas exchanges migrants with neighboring populations in western Texas, New Mexico (Chapter II) and perhaps Mexico. Successful reproduction by dispersers would increase genetic connectivity, genetic diversity and effective size; all of which are characteristic of healthy populations (e.g., Spong, Johansson & Björklund 2000). Overall, it is apparent that conservation programs are likely necessary to ensure the persistence of mountain lions in Texas. This work illustrates the utility of using museum collections and current genetic samples to examine population histories of wildlife that are data deficient and difficult to survey.
Citation:Holbrook, J. D. 2011. Exploring mountain lion ecology in Texas using genetic techniques. Thesis, Texas A&M University-Kingsville, USA.

Title:Noninvasive monitoring for ocelots in the Tamaulipan biotic province
Journal/Year:TPWD Final Report/2011
View:Download Tewes_2011_OcelotsTamaulipan.pdf
Author(s):Michael Tewes
Abstract:This survey produced 1,145 photos of about 53 different ocelots on private ranches in Texas and northeastern Mexico. We obtained access to several ranches that required confidentiality and that normally did not allow this type of monitoring. Most of these ocelots had not been previously identified, and this information provided a major improvement in our efforts to monitor population status and abundance. In addition, we created an Ocelot-Ranch Coalition of 19 strategically located properties that received information about our ocelot monitoring and management. A subset of this coalition allowed active monitoring for ocelots and these results were collectively called the "Willacy Ocelot Population Pool". This Willacy Ocelot Population Pool included the different ocelots identified on ranches requiring anonymity, and did not include the 8 ocelots identified on the Yturria Ranch. In addition, this monitoring found few sensitive carnivores in Texas. However, a greater number were found in Mexico with 225 photos of white-nosed coati; 48 photos of hog-nose skunk; 1 photo of long-tailed weasel; 177 photos of mountain lion; 1 photo of badger; 10 photos of eastern spotted skunk; and 128 photos of jaguarundi. This monitoring will continue past the ending dates of the contract period and this report period.
Citation:Tewes, M. 2011. Noninvasive monitoring for ocelots in the Tamaulipan biotic province. Texas Parks and Wildlife Department Final Report, Austin, USA.

Title:Female white-tailed deer body condition and diet after a large spring wildfire
Journal/Year:Rangeland Ecology and Management/2012
View:Visit BioOne - Female white-tailed deer body condition and diet after a large spring wildfire
Author(s):John S. Lewis|Robert D. Kaiser, III|David G. Hewitt|David R. Synatzske
Keywords:fetal growth|food habits|mesquite rangeland|Odocoileus virginianus|pregnancy|South Texas
Abstract:Frequency of large rangeland wildfires may increase in the southwestern United States and northeastern Mexico as a result of exotic grass invasion and reduced emphasis on livestock production, but effects of such fires on white-tailed deer (Odocoileus virginianus) are poorly documented. A large wildfire burned >90% of the 6 151-ha Chaparral Wildlife Management Area in southern Texas during March 2008, creating an opportunity to study short-term effects of wildfire on white-tailed deer food habits, body condition, and pregnancy. We harvested 26 female deer between 7 April and 20 June 2008 and recorded dressed body weight, body condition, number of corpora lutea, and number and size of fetuses. We used rumen contents to quantify forage classes consumed. Deer ate prickly pear (Opuntia engelmannii) pads and emergent grasses during April and shifted to forbs and browse as vegetation communities recovered. Deer consumed mesquite (Prosopis glandulosa) beans and prickly pear fruit during mid-June. Body condition measures did not vary during the collection period, suggesting deer were able to acquire sufficient nutrients to meet requirements. Fetal development rate appeared normal. Precipitation (11.4 cm) during late April and May probably allowed vegetation to recover from the wildfire. White-tailed deer are resilient opportunists and were able to maintain body condition and pregnancy after a large-scale wildfire.
Management Implications:Our findings suggest large spring wildfires are not necessarily detrimental to female white-tailed deer living in Tamaulipan thornscrub, and thus dramatic remedial actions, such as lowering deer density or supplemental feeding, are unnecessary. However, an adaptive management approach is suggested because differences in deer density, property size, and post-fire precipitation patterns could cause different outcomes.
Citation:Lewis, J. S., R. D. Kaiser, III, D. G. Hewitt, and D. R. Synatzske. 2012. Female white-tailed deer body condition and diet after a large spring wildfire. Rangeland Ecology and Management 65:309-312.

Title:Genetic diversity, population structure, and movements of mountain lions (Puma concolor) in Texas
Journal/Year:Journal of Mammalogy/2012
View:Visit BioOne - Genetic diversity, population structure, and movements of mountain lions (Puma concolor) in Texas
Author(s):Joseph D. Holbrook|Randy W. DeYoung|Jan E. Janecka|Michael E. Tewes|Rodney L. Honeycutt|John H. Young
Keywords:Bayesian clustering|genetic diversity|genetic structure|long-distance movement|mountain lion|Puma concolor|Texas
Abstract:Knowledge of population boundaries and long-distance movements is important for wildlife conservation. We used genetic tools to investigate genetic diversity, population structure, and movements of mountain lions (Puma concolor) in Texas. We amplified 11 microsatellite loci for 245 individuals collected during 1985-2010 from Texas and New Mexico. Bayesian clustering and values of FST suggested a partitioning of mountain lions into 3 genetically differentiated groups, New Mexico, western Texas, and southern Texas. New Mexico and western Texas exhibited moderate levels of genetic diversity (expected heterozygosity [HE]=0.61 and 0.58, respectively), whereas diversity in southern Texas was lower (HE = 0.47). Southern Texas displayed elevated genetic structure when compared to western Texas and New Mexico (FST = 0.102-0.148), whereas the comparison between New Mexico and western Texas revealed less subdivision (FST = 0.056). We documented long-distance movement among regions, and New Mexico and western Texas were sources for putative dispersers we sampled outside known populations. Differences in genetic structure and diversity between southern and western Texas support the designation of separate management units. Southern Texas appears isolated and further investigation is needed to determine the current population status. Mountain lion populations in New Mexico and western Texas may be important for future recolonization into portions of the southern United States.
Management Implications:We have shown that mountain lions in Texas and New Mexico represent 3 genetic groups at the regional level with differing levels of connectivity and genetic diversity. Further, populations in New Mexico, western Texas, and perhaps other unsampled populations are facilitating mountain lion movements into presumably unoccupied areas. These finding have clear implications for management and conservation. First, genetic diversity in New Mexico and western Texas is at seemingly high levels compared to that of other mountain lion populations (Culver et al. 2000), and probably will be maintained if effective population size remains large (Allendorf and Luikart 2007). Conservation strategies should aim at maintaining large effective sizes in these regions to perpetuate diversity and maintain large peripheral populations in the United States. Southern Texas, however, displayed lower levels of genetic diversity along with high levels of differentiation comparable to fragmented or isolated populations in California (Ernest et al. 2003). We did detect natural movements into southern Texas, but reproduction may be negated due to high mortality, as suggested by Harveson (1997). Natural dispersal into southern Texas is promising because it has the potential to increase diversity and reduce differentiation if reproduction occurs. Strategies should be implemented to increase survival of these immigrants during movement and after establishment if mountain lion persistence is desired. For instance, lowering harvest pressure in potential movement corridors into southern Texas from western Texas or Mexico could be 1 alternative. Estimates of population productivity and survival in southern Texas also would inform the status and future persistence of mountain lions in the region. Second, our findings suggest that mountain lions in the southwestern United States are not continuous (Logan and Sweanor 2001; Sweanor et al. 2000). Levels of differentiation between southern and western Texas are high, and similar to previous work despite our larger sample size and sampling area. Therefore, we support the suggestion by Walker et al. (2000) that western and southern Texas be treated as 2 management units. This information should be considered when implementing management prescriptions that impact regional mountain lion fitness. In addition, our results indicate that New Mexico and western Texas are separate units connected through moderate levels of genetic exchange. Maintaining connectivity among mountain lions in New Mexico, Texas, and perhaps Mexico will likely have a positive influence on regional persistence by sustaining large effective sizes. Finally, mountain lions from New Mexico and western Texas are emigrating into portions of their historical range, suggesting that these 2 regions may serve as sources for future recolonization in the southern United States. Further identification and maintenance of potential source populations and corridors for dispersal would help prioritize conservation efforts as well as help minimize mountain lion–human conflict, both of which are imperative for the future of mountain lion conservation (Hornocker 2010).
Citation:Holbrook, J. D., R. W. DeYoung, J. E. Janecka, M. E. Tewes, R. L. Honeycutt, and J. H. Young. 2012. Genetic diversity, population structure, and movements of mountain lions (Puma concolor) in Texas. Journal of Mammalogy 93:989-1000.

Title:Understanding functional connectivity in shortgrass and mixedgrass prairies using the swift fox as a model organism
View:Download Schwalm_2012_PrairiesSwiftFoxDissertation.pdf
Author(s):Donelle L. Schwalm
Abstract:Habitat fragmentation and loss are the greatest sources of biodiversity loss today. The negative relationship between these phenomena and myriad ecological processes are well-documented. Chief amongst these impacts is the disruption of dispersal regimes, resulting in isolated or semi-isolated groups. Reduced dispersal in turn negatively influences gene flow between groups of individuals, resulting in reduced genetic diversity, increasing risk of inbreeding depression and, ultimately, heightened extinction risk. Thus, maintaining functional connectivity in ecosystems is high on the list of conservation priorities. The Great Plains is a vast ecosystem characterized by habitat fragmentation natural and anthropogenic in origin. Remnant shortgrass and mixedgrass prairies, in which this study occurs, have been reduced to < 50% of their previous extensive geographic area, largely due to agricultural development. Anthropogenic impacts on connectivity are predicted to increase, resulting in loss of up to 50% of remnant native grasslands. Thus, understanding these factors' influence on grassland connectivity is critical for conservation and management in both contemporary and future time scales. Here, I employed a landscape genetics approach to address a series of objectives, which include assessing current and historic genetic diversity and structure in swift fox populations, relating gene flow and genetic structure patterns to landscape influences, and providing insight into conservation needs for the species. In addition, I used the swift fox as a model species to elucidate connectivity patterns across two focal areas in the shortgrass and mixedgrass prairies, ultimately presenting functional connectivity maps for these regions. Finally, I developed a new method for studying connectivity networks in fragmented populations with empirically derived cost metrics, and demonstrated its utility for identifying movement corridors using leastcost path modeling; this analysis was conducted in a fragmented swift fox population wherein genetic diversity appears to be linked to inter-population movement; thus identification of movement corridors is a critical conservation need locally.
Management Implications:Movement between subgroups in the regional population appears to be a critical process for maintaining genetic diversity in fragmented habitats. Thus, swift fox management should emphasize connectivity conservation at a multi-state level. This will require identifying and conserving extant corridors, which may be few in number and narrow in width in this impacted region. Sohl et al. (2012) predict as much as 50% of remnant grassland will be lost within the region in the next ~90 years; preemptive grassland conservation is therefore critical for connectivity conservation. Although patches of grassland are conserved as part of the Forest Service National Grassland system (e.g., the Rita Blanca and Kiowa National Grasslands), the vast majority of shortgrass and mixedgrass prairie in the study area is privately owned and vulnerable to further development. Thus, managing for connectivity will require coordination between private landowners and state and federal agencies for success. In the study area, swift fox management varies by state. In all four states the swift fox is listed as a furbearer; however, in Colorado and Oklahoma the season is closed, whereas in New Mexico and Texas, swift fox can be harvested during regulated seasons. These results imply that genetic diversity in the eastern group, which exists primarily in Texas, is maintained by high immigration from the central group; furthermore, population numbers in the Texas population appear to benefit from immigration, with nearly 30% of resident foxes originating from other sources. At minimum, I encourage managers to afford the swift fox in Texas greater protection. Reliance on support from other populations is a tenuous option, given anticipated future connectivity reductions in the face of grassland conversion. Given the aforementioned limitations of the sample distribution in New Mexico, I am hesitant to extend recommendations for this region, but urge caution in management decisions, given the limited indication of gene flow my results imply.
Citation:Schwalm, D. L. 2012. Understanding functional connectivity in shortgrass and mixedgrass prairies using the swift fox as a model organism. Dissertation, Texas Tech University, Lubbock, USA.

Title:Continued surveillance and monitoring for white-nose syndrome in Texas bats
Journal/Year:TPWD Final Report/2013
View:Download BCI_2013_WhiteNoseSyndrome.pdf
Author(s):Bat Conservation International/2013
Citation:Bat Conservation International. 2013. Continued surveillance and monitoring for white-nose syndrome in Texas bats. Texas Parks and Wildlife Final Report, Austin, USA.

Title:Ecology of Catarina virus (family Arenaviridae) in southern Texas, 2001-2004
Journal/Year:Vector-borne and Zoonotic Diseases/2013
View:Visit Mary Ann Liebert, Inc. Publishers - Ecology of Catarina virus (family Arenaviridae) in southern Texas, 2001-2004
Author(s):Mary L. Milazzo|Brian R. Amman|Maria N. B. Cajimat|Francisca M. Mendez-Harclerode|John R. Suchecki|J. Delton Hanson|Michelle L. Haynie|B. Dnate' Baxter|Ciro Milazzo, Jr.|Serena A. Carroll|Darin S. Carroll|Donald C. Ruthven, III|Robert D. Bradley|Charles F. Fulhorst
Keywords:arenavirus|Arenaviridae|Catarina virus|Neotoma micropus|Southern plains woodrat|Tacaribe serocomplex
Abstract:A total of 3941 rodents were captured during a 46-month prospective (mark-recapture) study on the ecology of Catarina virus in southern Texas. Antibody reactive against Catarina virus was found in 73 (11.9%) of 611 southern plains woodrats (Neotoma micropus) and none of 3330 other rodents; strains of Catarina virus were isolated from 6 antibody-negative and 9 antibody-positive southern plains woodrats; and the infections in at least 3 southern plains woodrats were chronic. These results affirm the notion that the southern plains woodrat is the principal host of Catarina virus and suggest that Catarina virus infection is highly specific to N. micropus.
Management Implications:The results of a previous study (Milazzo et al. 2011) suggested that arenaviruses naturally associated with woodrats (Neotoma spp.) are etiological agents of acute central nervous system disease or undifferentiated febrile illnesses in humans in the United States. It is generally accepted that humans usually become infected with arenaviruses by inhalation of virus in aerosolized droplets of saliva, respiratory secretions, urine, or blood from infected rodents. The isolation of CTNV from samples of OPsec or urine from woodrats in this study suggests that secretions and excretions from naturally infected southern plains woodrats may be infectious to humans. Neotoma micropus in Texas is principally associated with habitats dominated by cactus or thorny desert shrubs (Braun and Mares 1989). As such, persons who work, live, or enjoy outdoor activities in rural areas in southern Texas may be at risk of CTNV infection.
Citation:Milazzo, M. L., B. R. Amman, M. N. B. Cajimat, F. M. Mendez-Harclerode, J. R. Suchecki, J. D. Hanson, M. L. Haynie, B. D. Baxter, C. Milazzo, Jr., S. A. Carroll, D. S. Carroll. D. C. Ruthven, III, R. D. Bradley, and C. F. Fulhorst. 2013. Ecology of Catarina virus (family Arenaviridae) in southern Texas, 2001-2004. Vector-borne and Zoonotic Diseases 13:50-59.

Title:Investigation of diseases occurring in pronghorn
Journal/Year:TPWD Final Report/2013
View:Download Gray_2013_PronghornDiseases.pdf
Author(s):Shawn S. Gray
Abstract:Hunter-harvested pronghorn from the Trans-Pecos ecoregion were collected during October 2009-2011, to evaluate parasite loads, titers to blue tongue (BT) and epizootic hemorrhagic disease (EHD), and copper and selenium levels. A total of 102, 95, and 49 pronghorn samples were obtained in 2009, 2010, and 2011, respectively. Prevalence of barber pole worms (Haemonchus spp.) was 94% (201 of 215 samples) for pronghorn that were analyzed. In 2009, the average number of barber pole worms per pronghorn was 510 and ranged from 0-4,080. The mean in 2010 was 286 worms, which was 44% less than 2009, but parasite loads still ranged from 0-3,145. In 2011, worm loads increased to 381 worms per pronghorn. In June/July of 2011, fecal samples were collected from 64 individuals throughout the Trans-Pecos the fecal egg counts averaged 1,271 eggs/gram. In July of 2012, fecal samples were collected from 27 individuals and fecal egg counts averaged 173 eggs/gram. The McMaster's fecal flotation technique was significantly correlated to abomasal worm counts; therefore, was used to increase sample size and compare worm loads temporally. The occurrence of BT and EHD titers were similar for each year. Copper levels in blood serum were highest in 2011 (0.84 ppm), while liver samples contained the highest copper concentrations in 2010 (8.56 ppm). Selenium levels from whole blood varied from 133.88 ppb in 2009 to 212.10 ppb in 2011. Samples were also taken from Panhandle pronghorn in 2010, 2011, and 2013. In 2010, samples were collected from 20 harvested pronghorn during January. Average Haemonchus spp. load was 90.1 worms per abomasum. Copper levels from liver tissues averaged 10.41 ppm, and copper levels from blood samples averaged 0.40 ppm. The mean selenium level from whole blood samples was 164.4 ppb. In July 2011, fecal samples were obtained from 20 individuals with the average fecal egg count of 608 eggs/gram. In February 2011 and January/February 2013, samples were collected from approximately 200 and 130 translocated pronghorn, respectively. Average fecal egg count for both years was very low. Average copper levels were 0.74 ppm with mean selenium levels being 208.43 ppb in 2011. Average copper, selenium, and iron levels for 2013 were 0.63 ppm, 283 ppb, and 2.1 ppm, respectively. The prevalence of titers for BT was 87% and 50.5% for EHD in 2011 with increasing prevalence in 2013. A total of 198 samples were tested for brucellosis in 2011 with none having the disease. In 2013, a commercial dewormer was given to 93 translocated pronghorn. Parasite monitoring, post-release, was done by fecal sample collection. Fecal samples were collected from treated, untreated, and local animals with no difference between fecal egg counts between groups. Fawns were captured from 4 disease sampling units throughout the Trans-Pecos in 2010 and 2011. A total of 60 fawns were captured and collared during May-June each year. Average fawn weight was 5.1 lbs in 2010 and 8.4 lbs in 2011. Mean fawn age at time of capture was about 11 days old. A total of 52 mortalities and 8 surviving fawns were recorded. Predation accounted for 92.3% (48/52) of the mortality for collared fawns. Coyote predation was 25.0% (13/52), whereas bobcat predation averaged 30.8% (16/52).
Citation:Gray, S. S. 2013. Investigation of diseases occurring in pronghorn. Texas Parks and Wildlife Department Final Report, Austin, USA.

Title:Morphological characteristics and effects of Telazol on American badgers in south Texas
Journal/Year:The Texas Journal of Agriculture and Natural Resource/2013
View:Download Collins_etal_2013_BadgerTelazol.pdf
Author(s):Daniel P. Collins|Louis A. Harveson|Donald C. Ruthven
Keywords:badger|Taxidea taxus|morphological characteristics|Telazol|south Texas
Abstract:Five North American badgers were trapped on the Chaparral Wildlife Management Area located in Texas counties Dimmit and LaSalle Texas in 2002. Mean male badger weight was 6.29 ± 0.76 kg and weight for a female badger was 5.44 ± 0.00 kg. Weights resulted in a mean dosage of 0.75 ± 0.24 cc of Telazol® with a workable time of 7.25 minutes. We concluded that badgers can be safely immobilized under field conditions using Telazol.
Management Implications:Studies involving badgers conclude that restraint is the number one issue when handling badgers for injection. Fitzgerald (1973) reported the defensive postures assumed by badgers made it difficult to handle and estimate weight. He suggested forcing captured individuals into a restraining cone once a neck noose was around the individual, but found it to be unsuccessful. Bailey (1971) suggested using a pole mounted syringe; however, it is easy to miss muscle mass with the injection being subcutaneous, prolonging immobilization. The badgers we captured were caught with both hind feet in a trap allowing us to place the pole noose around their head and to stretch the individual out flat, making it difficult for the badger to assume any defensive posture. We would approach the badger from the back side, minimizing movement to reduce additional stress on the badger. While capture by both hind legs was more than likely an anomaly, we would suggest being prepared with both a pole-mounted syringe and a pole noose (Ketch-all®, San Luis Obispo, California) to allow for flexibility in handling the captured animal. A pole-mounted syringe would allow for injection if the captured individual was in an awkward space or position, making approach to the animal difficult. However, this situation would increase the risk of injury to the animal as Bailey (1971) suggested. A pole noose allows for approach to captured animals no matter which leg is contained within the leg hold trap, giving the researcher the opportunity to immobilize the animal and provide an unobstructed view for injection of the selected immobilizing agent. Injection was always done in the hind quarter with a 16-gauge syringe containing the estimated dosage of Telezol. Individuals were completely anesthetized before being approached for data collection. In conclusion, badgers in this study exhibited variation in morphology that has been previously reported in past studies across their range and were anesthetized successfully using a single intramuscular injection which provided an adequate field immobilization time for all data collection and handling procedures.
Citation:Collins, D. P., L. A. Harveson, and D. C. Ruthven. 2013. Morphological characteristics and effects of Telazol on American badgers in south Texas. The Texas Journal of Agriculture and Natural Resources 26:25-31.

Title:Plant and small vertebrate composition and diversity 36-39 years after root plowing
Journal/Year:Rangeland Ecology and Management/2013
View:Visit BioOne - Plant and small vertebrate composition and diversity 36-39 years after root plowing
Author(s):Timothy E. Fulbright | E. Alejandro Lozano-Cavazos | Donald C. Ruthven, III | Andrea R. Litt
Keywords:amphibians | brush management | Prosopis glandulosa | reptiles | rodents | woody plants
Abstract:Root plowing is a common management practice to reduce woody vegetation and increase herbaceous forage for livestock on rangelands. Our objective was to test the hypotheses that four decades after sites are root plowed they have 1) lower plant species diversity, less heterogeneity, greater percent canopy cover of exotic grasses; and 2) lower abundance and diversity of amphibians, reptiles, and small mammals, compared to sites that were not disturbed by root plowing. Pairs of 4-ha sites were selected for sampling: in each pair of sites, one was root plowed in 1965 and another was not disturbed by root plowing (untreated). We estimated canopy cover of woody and herbaceous vegetation during summer 2003 and canopy cover of herbaceous vegetation during spring 2004. We trapped small mammals and herpetofauna in pitfall traps during late spring and summer 2001-2004. Species diversity and richness of woody plants were less on root-plowed than on untreated sites; however, herbaceous plant and animal species did not differ greatly between treatments. Evenness of woody vegetation was less on root-plowed sites, in part because woody legumes were more abundant. Abundance of small mammals and herpetofauna varied with annual rainfall more than it varied with root plowing. Although structural differences existed between vegetation communities, secondary succession of vegetation reestablishing after root plowing appears to be leading to convergence in plant and small animal species composition with untreated sites.
Management Implications:A concern regarding use of root plowing to manage woody plants is that it can cause permanent changes in vegetation structure and composition that are undesirable for wildlife. Based on our long-term (>three decades) data, root plowing should be avoided if land managers wish to maintain woody plant species richness and diversity. Effects of root plowing, however, do not appear to be a conservation concern for small vertebrate communities on the Chaparral Wildlife Management Area in Texas.
Citation:Fulbright, T. E., E. A. Lozano-Cavazos, D. C. Ruthven, III, and A. R. Litt. 2013. Plant and small vertebrate composition and diversity 36-39 years after root plowing. Rangeland Ecology and Management 66:19-25.

Title:The role of parasites, diseases, mineral levels, and low fawn survival in a declining pronghorn population in the Trans-Pecos region of Texas
View:Download Weaver_2013_PronghornThesis.pdf
Author(s):James H. Weaver
Abstract:Since the late 1980s, pronghorn populations of west Texas have been in a steady decline. Texas Parks and Wildlife Department's (TPWD) 2012 surveys showed that the population was estimated at 2,751 animals, a 75-year low for the region. In 2009, a study was initiated to determine some of the leading causes for the recent decline in this region, including prevalence of diseases, mineral concentrations, parasites, and fawn survival. I found an average prevalence of titers for blue tongue virus (BTV) to be 97% and 92% for epizootic hemorrhagic disease (EHD) in 2010 and 2011, respectively. Because trace mineral levels (e.g., copper and selenium) have also been tied to productivity in pronghorn, I compared mineral levels between the Trans-Pecos and Panhandle. Copper serum levels were the same between regions (P = 0.199), but copper liver levels (P = 0.002), and selenium levels were different (P < 0.001). I also investigated the roles of parasites and predation as a limiting factor for pronghorn production in the Trans-Pecos. I found a difference when comparing Haemonchus worm counts (P = 0.041) and fecal egg counts (P < 0.001) between regions (Trans-Pecos, Panhandle). In 2011, surveys showed some areas to have fawn crops as low as 0% (0 fawns: 100 does), with a Trans-Pecos average at 10%. In 2012, TPWD surveys indicated that the fawn crops averaged about 16% Trans-Pecos wide. I conducted a pronghorn fawn survival study to determine major causes of mortality. Predation was the major cause of mortality in both 2011 and 2012. Bobcat (Lynx rufus) predation accounted for 32%, unknown predation accounted for 28%, and coyote (Canis latrans) predation accounted for 24% of all mortalities. Marginal mineral levels, high Haemonchus loads, and high predation on pronghorn fawns appear to be having a negative impact on pronghorn populations in the Trans-Pecos.
Citation:Weaver, J. H. 2013. The role of parasites, diseases, mineral levels, and low fawn survival in a declining pronghorn population in the Trans-Pecos region of Texas. Thesis, Sul Ross State University, Alpine, TX, USA.

Title:Using GIS-based, regional extent habitat suitability modeling to identify conservation priority areas: a case study of the Louisiana black bear in east Texas
Journal/Year:Journal of Wildlife Management/2013
View:Visit Wiley Online Library - Using GIS-based, regional extent habitat suitability modeling to identify conservation priority areas: a case study of the Louisiana black bear in east Texas
Author(s):Dan J. Kaminski|Christopher E. Comer|Nathan P. Garner|I-Kuai Hung|Gary E. Calkins|
Keywords:conservation|east Texas|geographic information systems (GIS)|geospatial modeling|habitat suitability index (HSI)|Louisiana black bear|priority areas|Ursus americanus luteolus
Abstract:State and federal recovery plans mandate that priority areas for future population expansion be identified within the historical range of the Louisiana black bear (Ursus americanus luteolus). Despite the presence of potentially suitable habitat in east Texas and expanding populations in adjacent states, quantitative estimates of regional habitat suitability do not exist. We developed a regional extent habitat suitability index (HSI) model in a geographic information system (GIS) to evaluate year-round habitat requirements for black bears in the 43,530-km2 south black bear recovery zone in southeastern Texas. We measured hard and soft mast production, understory vegetation density, and tree den availability at 516 survey points in 38 habitat classes (82% of the total area in the south recovery zone). We developed geospatial models for summer food availability; fall food availability, diversity, and productivity; protection cover, tree den availability, distance to roads, and human development zones and calculated HSI scores per pixel in a continuous dataset. Habitat suitability scores ranged from 0.00 to 0.76 throughout southeastern Texas. Highly (< 1%) and moderately (16%) suitable habitat existed in the region, although most area (84%) was classified as marginal or unsuitable habitat. We identified 4 recovery units comprising >20,700 ha (mean HSI=0.5) capable of sustaining viable black bear populations. These units ranged from 62,844 ha to 124,808 ha in size and suitable habitat pixels within units ranged from 0.58 to 0.60 in mean HSI scores. Recovery unit scores were comparable to those previously reported for occupied bear range in the southeastern United States and acreages of suitable habitat exceeded those estimated to support existing Louisiana black bear populations.
Management Implications:Our results indicate that areas of large, contiguous forested habitat capable of meeting the year-round habitat requirements of Louisiana black bears and sustaining viable populations exist within the historical range of the subspecies in east Texas. The identification of recovery units based on the ecological requirements of black bears provides areas in which future management, research, public outreach, or reintroduction efforts may be targeted. The recovery units we presented are each comprised of >80% private landownership, which emphasizes the need to incorporate public outreach and education with management actions, and to develop incentive programs for private landowners to conserve high-quality habitats for the long-term. Collaboration with private landowners to implement uneven-aged and/or longer rotation forest management could boost fall food variables in critical bottomland hardwood habitats and improve overall HSI estimates. However, because forest management practices and recovery-unit HSI estimates in east Texas are similar to those in areas with established black bear populations in the southeastern United States, we suggest that habitat fragmentation and the conversion of forestlands to less renewable resources poses a greater risk to the sustainability of recovery units. Thus management actions should focus on preserving large contiguous forested habitats free of human disturbance in and around recovery units.
Citation:Kaminski, D. J., C. E. Comer, N. P. Garner, I. Hung, and G. E. Calkins. 2013. Using GIS-based, regional extent habitat suitability modeling to identify conservation priority areas: a case study of the Louisiana black bear in east Texas. Journal of Wildlife Management 77:1639-1649.