Trans-Pecos Region Of Texas Research Articles

Comparing Survival and Cause-Specific Mortality of Different Translocation Release Methods for Desert Bighorn Sheep

Historically, desert bighorn sheep (Ovis canadensis mexicana) were prevalent throughout the Trans-Pecos region of Texas. However, they were extirpated by the 1960s due to unregulated hunting, habitat loss, predation, and disease transmission from livestock. Restoration efforts have been successfully conducted by the Texas Parks and Wildlife Department to increase population numbers of resident (i.e., animals that currently populate a region of interest) desert bighorn sheep at Black Gap Wildlife Management Area (BGWMA) through the use of translocations. Because there is a lack of knowledge on alternative release methods for large mammal translocations, our goals were to monitor cause-specific mortality and postrelease survival of desert bighorn sheep translocated during 2017. Survival estimates of desert bighorn sheep were compared amongst resident, hard-released, and soft-released individuals throughout the study. In winter 2017–2018, we radio-collared and released 30 resident (8 M, 22 F) and 70 within-state-translocated (36 M, 34 F) desert bighorn to BGWMA. Of the 70 translocated individuals, 28 (12 M, 16 F) were hard released (i.e., released immediately onto the landscape) and 42 (24 M, 18 F) were soft released (i.e., released into an enclosure before onto the landscape). Resident desert bighorn had the highest probability of survival over time (Ŝ = 0.83), followed by hard-released (Ŝ = 0.67) and then soft-released (Ŝ = 0.54) individuals. To date, 26 mortalities (13 M, 13 F) were recorded. Of those mortalities, 4 were residents (15%), 6 were hard released (23%), and 16 were soft released (62%). The soft release is thought to be a better strategy for translocating large mammals; however, in this study, it did not improve survival. Survival is potentially influenced by acclimation time and individual exit strategy from the soft-release pen, which should be managed for future restoration efforts. Incorporating a flushing-method exit strategy would aid in removing soft-released individuals from the high-fenced pen simultaneously and may increase survival estimates. This could potentially allow individuals to form larger groups when exiting the enclosure and entering the new habitat. The soft-release method is also more costly to implement, which could be challenging for wildlife managers.

Movement ecology and space-use by mountain lions in West Texas

Local knowledge regarding the movements and space-use of large carnivores can inform species’ management, conservation planning, and strategies for reducing human-wildlife conflict. However, because issues regarding large carnivores can be controversial, obtaining such information may be difficult and therefore lacking in many places. Such is the case for mountain lions ( Puma concolor ) in West Texas, where most of the land is privately owned. Therefore, we sought to better understand movements and home ranges of mountain lions in the Trans-Pecos region of Texas. We GPS collared 24 mountain lions (15 females, 9 males) between 2011 and 2017. We inspected variograms to distinguish dispersers from residents then we estimated movement metrics and home ranges using continuous-time movement models and autocorrelated kernel density estimation. Using generalized linear mixed models, we tested for seasonal differences in all movement and home range metrics. Of three subadults that dispersed, one had data appropriate for speed estimation; she exhibited faster speeds while dispersing than while exhibiting philopatric movements. Compared to adult resident males, adult resident females moved with slower average speeds (females: 11.82 ± 0.43 km/day; males: 20.36 ± 2.86 km/day), exhibited similar directional persistence in movement (females: 0.95 ± 0.14 h; males: 1.12 ± 0.21 h), crossed their home ranges in similar times (females: 5.76 ± 0.98 days; males: 7.07 ± 1.34 days), and used smaller home ranges than males (females: 283.83 ± 37.50 km 2 : males: 1077.95 ± 219.30 km 2 ). Adults moved with slowest speeds in the cold-dry season; there were no seasonal effects on other estimates. Each individual’s successive seasonal home ranges were highly overlapped (0.95 ± 0.01). The mountain lions did not expand, contract, or shift their home ranges seasonally, which may be due to ample prey-availability and limited seasonal-shifts in prey distribution. Mountain lions used areas larger than most local ranches and tended to move across the landscape quickly. Together, our results indicate that mountain lions do not typically stay on one property for long which may have implications for conservation planning and species management.

First Record and Diet of the Tri-Colored Bat (Perimyotis subflavus) from Guadalupe Mountains National Park and Culberson County, Texas

The tri-colored bat (Perimyotis subflavus) occurs throughout the eastern United States, from Canada to south Florida and westward to eastern New Mexico, central Colorado, and western Texas. In this study, we document the first record of P. subflavus for both Guadalupe Mountains National Park and Culberson County, Texas. Our record extends the range of P. subflavus into the Trans-Pecos region of Texas. We also examined the diet of this individual and observed that it consisted of Lepidoptera, Coleoptera, and Hemiptera. Our observations of the diet of P. subflavus correspond with results of previous studies from more eastern portions of the species' range.

Low Trypanosoma cruzi transmission risk to humans in the Trans-Pecos region of Texas

In the Trans-Pecos region of Texas, reports of domestic triatomine bites were common (67%), with 36% of residentially collected triatomines positive for Trypanosoma cruzi. Despite the transmission potential, no human infections were detected. Collected Triatoma rubida species were themselves frequently parasitized with mites.

Rickettsia parkeri (Rickettsiales: Rickettsiaceae) in the Sky Islands of West Texas.

Rickettsia parkeri, a tick-borne pathogen distributed throughout several countries of the Americas, causes a mild to moderately severe, eschar-associated spotted fever rickettsiosis. Although most U.S. cases of R. parkeri rickettsiosis are reported from southeastern states, some have been reported recently from remote regions of southern Arizona. These cases are linked to R. parkeri-infected ticks of the Amblyomma maculatum (Acari: Ixodidae) group found in several isolated mountain ranges of southern Arizona and New Mexico, referred to as 'sky islands'. Archival records also document ticks of the A. maculatum group collected from domestic and wild animals in West Texas. We surveyed sites in two sky island chains of Jeff Davis and Brewster counties to document the off-host occurrence of these ticks and identify the presence of R. parkeri in the Trans-Pecos region of Texas. During August 2019, 43 adult A. maculatum group ticks were flagged from vegetation or removed from a road-killed, female mule deer. Of 39 samples evaluated by PCR, eight contained a partial sca0 sequence with complete identity to R. parkeri and two with complete identity to 'Candidatus Rickettsia andeanae', a species of undetermined pathogenicity. Four isolates of R. parkeri were obtained using cell culture. Persons at risk for R. parkeri rickettsiosis include those who work or recreate in these mountains, such as hikers, backpackers, research scientists, foresters, and border enforcement personnel. Additional investigations are needed to define the distribution of these medically important arthropods in other parts of the southwestern United States and northern Mexico.

A new petrophilous tiger beetle from the Trans-Pecos region of Texas and revised key to the genus Amblycheila (Coleoptera, Carabidae, Cicindelinae).

A new rock-dwelling (petrophilous) tiger beetle, Amblycheila katzi Duran & Roman, sp. nov. is described from calcareous canyons and steep hillsides in the Trans-Pecos region of western Texas. It is distinguished from all other Amblycheila based on multiple morphological characters, biogeography, and ecology. A revised key to the genus Amblycheila is provided.

A new petrophilous tiger beetle from the Trans-Pecos region of Texas and revised key to the genus Amblycheila (Coleoptera, Carabidae, Cicindelinae)

A new rock-dwelling (petrophilous) tiger beetle, Amblycheila katzi Duran & Roman, sp. nov. is described from calcareous canyons and steep hillsides in the Trans-Pecos region of western Texas. It is distinguished from all other Amblycheila based on multiple morphological characters, biogeography, and ecology. A revised key to the genus Amblycheila is provided.

SELECTION OF ECOLOGICAL SITES BY PRONGHORN IN TRANS-PECOS REGION OF TEXAS

Rangeland managers use the ecological site concept to segment rangelands into discrete areas capable of supporting a particular suite of vegetation. Ecological site data are easily accessible and standardized in the Soil Survey Geographic Database published by the Natural Resources Conservation Service. While widely used in range management, wildlife managers have only recently explored the usefulness of ecological site data in delineating wildlife habitat. We undertook this study to assess pronghorn selection of ecological sites across two seasons (warm-dry and warm-wet) following translocation to the Trans-Pecos region of Texas in 2013. We observed seasonal shifts in selection with selection of draws and limestone hills in the warm-wet season and selection of clay flats in both seasons. Pronghorn avoided other sites or used them in proportion to their availability. Our results suggest that ecological sites provide a valid means of segmenting wildlife habitats and identifying important sites for management of pronghorn.

Scaled Quail Reproduction in the Trans-Pecos Region of Texas

Scaled quail (Callipepla squamata) populations have declined markedly throughout their range. We monitored hatch rates and nest placement of radio-marked female scaled quail (n 1⁄4 210) in Pecos County, Texas relative to the availability and location of ‘spreader dams’ (i.e., shallow water catchments) through the nesting seasons of 1999 and 2000. Hatch rates were high both years (i.e., 67 and 84% for 1999 and 2000, respectively). The predominant nesting microhabitat was tobosa (Pleuraphis mutica), which accounted for 85% of the nests located. We failed to document any direct impacts of spreader dams on nesting ecology of scaled quail.

Species Delimitation and Morphological Divergence in the Scorpion Centruroides vittatus (Say, 1821): Insights from Phylogeography

Scorpion systematics and taxonomy have recently shown a need for revision, partially due to insights from molecular techniques. Scorpion taxonomy has been difficult with morphological characters as disagreement exists among researchers with character choice for adequate species delimitation in taxonomic studies. Within the family Buthidae, species identification and delimitation is particularly difficult due to the morphological similarity among species and extensive intraspecific morphological diversity. The genus Centruroides in the western hemisphere is a prime example of the difficulty in untangling the taxonomic complexity within buthid scorpions. In this paper, we present phylogeographic, Ecological Niche Modeling, and morphometric analyses to further understand how population diversification may have produced morphological diversity in Centruroides vittatus (Say, 1821). We show that C. vittatus populations in the Big Bend and Trans-Pecos region of Texas, USA are phylogeographically distinct and may predate the Last Glacial Maximum (LGM). In addition, we suggest the extended isolation of Big Bend region populations may have created the C. vittatus variant once known as C. pantheriensis.

Abundance, Distribution, and Habitat of the Threatened MinnowsCampostoma ornatumandNotropis chihuahuain the Trans-Pecos Region of Texas

Abstract The Rio Grande and its tributaries in the Trans-Pecos region of Texas have been impacted by a variety of anthropogenic activities such as dewatering and the introduction of nonnative species. These environmental manipulations have negatively affected the native fishes leading to extirpations and declining populations throughout the region. Campostoma ornatum and Notropis chihuahua inhabit tributary streams of the Rio Grande in the Trans-Pecos region and are considered as state-listed threatened species. Little is known about their status and ecological requirements in the region. We hypothesized that the distribution and abundance of these threatened minnows in these spring-fed habitats can be modeled by two primary factors: local environmental conditions that are maintained by spring flow and the abundance of introduced species such as the plains killifish, Fundulus zebrinus. We used classification and regression trees to analyze variation in abundance and incidence of the target species from Al...

Habitat Characteristics of Winter Roost Sites of Wild Turkeys in Trans-Pecos, Texas

Abstract Wild turkeys (Meleagris gallopavo) occur intermittently throughout Trans-Pecos, Texas. In the lower desert of the Trans-Pecos, turkeys are associated strongly with the limited riparian habitat where roosting habitat is found. We initiated a study to document microhabitat characteristics of roost sites in the Trans-Pecos region of Texas. We measured microhabitat characteristics (canopy cover, density of stand, visual obstruction, understory herbaceous cover, height of tree, diameter at breast height (dbh), height-to-lowest live branch, slope, and aspect) at 15 winter roosts and 15 random sites in three habitats in the Trans-Pecos region: ponderosa pine (Pinus ponderosa), live oak (Quercus virginiana), and sugar hackberry (Celtis laevigata). All roost sites were <1 km from riparian corridors and located in riparian regions. Among the three habitats, large diameters and height of trees were a prerequisite for roost trees in live oak and sugar hackberry habitat, where live oaks used as roost trees we...

Predicting Private Landowner Support toward Recolonizing Black Bears in the Trans-Pecos Region of Texas

Black bears (Ursus americanus) began recolonizing the Trans-Pecos region of Texas from Mexico in the late 1980s after a 30-year absence. This region is predominately a ranching community and knowledge of landowner attitudes is essential to development of management plans for this population. We surveyed 1,100 landowners in the region to measure their response toward the natural recolonization of black bear in the Trans-Pecos. More positive scores toward black bear recolonization came from younger, more educated landowners who had owned land for less than three generations. Of the landowners against recolonization most (52%) believed that livestock losses would be excessive. Managers would benefit by focusing their efforts on increasing awareness of methods for preventing black bear damage to landowners with negative attitudes and those owning large parcels (>4,048 ha) of land possibly containing potential bear habitat. It is important that managers consider and incorporate landowners when managing this increasing black bear population.

Cotton Response to Phosphorus Fertigation Using Subsurface Drip Irrigation

Subsurface drip irrigation (SDI) has expanded dramatically in cotton producing areas of the southwest United States, especially where furrow irrigation was practiced. There is ancillary evidence that cotton may experience shortages of phosphorus (P) and other nutrients more readily under SDI compared with furrow irrigation. This may be related to the smaller wetted volume of soil and hence smaller root volume under SDI. Some cotton producers using SDI in the Trans Pecos region of Texas have observed large increases in cotton lint yield by the addition of small amounts of P; however, cotton response to different P rates under SDI has not been documented in this region. This article presents results of a field experiment repeated during the 2003, 2004, and 2005 growing seasons where cotton lint yield, quality characteristics, and lint gross return were evaluated for different P application rates. The experiment was completely randomized with four treatments and three replications. Treatments were: 1) no phosphorus applications; 2) injection of 4.6 kg ha-1 y-1 P contained in Miller Solugro (12-48-8); 3) injection of 32.9 kg ha-1 y-1 P contained in phosphoric acid; 4) injection of 65.7 kg ha-1 y-1 P contained in phosphoric acid. The cost of P treatments ranged from $21.10 to $42.20 ha-1 y-1, but marginal gross returns for lint were $520 to $1,252 ha-1 y-1 more from phosphoric acid and $233 to $872 ha-1 y-1 more from Miller Solugro. In 2003 and 2004, lint yields and gross returns were greatest for the 65.7-kg ha-1 y-1 P rate, which was similar to recommended rates based on a 2004 soil fertility analysis. In 2005, lint yields and gross returns were greatest for the 32.9-kg ha-1 y-1 P rate, which was slightly below recommended rates based on pre-plant 2005 soil fertility analysis. These results support injecting P at rates based on soil fertility analyses. Both phosphoric acid and Miller Solugro were suitable for injecting P into SDI systems. The P2O5 application rates increased the productivity per unit of water applied during the three years of the study. Plant petiole analysis in 2004 correlated with P application rates, suggesting a qualitative method to detect P deficiencies during the growing season.

Partial ecological life table of immature Helicoverpa zea (Lepidoptera: Noctuidae) in an irrigated cotton cropping system in the Trans-Pecos region of Texas, USA

During the summers of 1996 and 1997 cotton bollworm, Helicoverpa zea (Boddie), life stages were sampled in insecticide-free, irrigated cotton, Gossypium hirsutum L., in the Trans-Pecos region of Texas. Partial ecological life tables were constructed for one generation of H. zea in each of the two growing seasons. Partial generation mortality (egg to fifth-instar) surpassed 97% in both years. The egg stage exhibited the greatest amount of real (r x ) and apparent (q x ) mortality followed by the third-instar. One hundred percent of the collected life stages consisted of H. zea. Egg parasitism ranged from 4.1 to 6% and egg predation by Orius tristicolor (White) was 4.1% in 1996 and 13.2% in 1997. Unexplained factors made the greatest contribution to H. zea mortality regardless of the life stage sampled. Each cotton bollworm generation monitored in 1996 and 1997 exhibited a Type III survivorship curve. As a result of the extensive early life stage mortality, rescue management tactics associated with contemporary H. zea control in the region appears to be generally unnecessary for cotton grown under irrigation in the Trans-Pecos region.

Extension of Laramide magmatism in southwestern North America into Trans-Pecos Texas

The Red Hills intrusion hosts the easternmost porphyry copper-molybdenum system in southwestern North America and consists of quartz-sulfide stockwork veins in sericitized porphyritic quartz monzonite. Zircon U-Pb and molybdenite Re-Os analyses yield ages of 64.2 ′ 0.2 Ma and 60.2 ′ 0.3 Ma, respectively, indicating that the Red Hills intrusion and mineralization are distinctly older than all other Tertiary magmatism (48-17 Ma) in the Trans-Pecos region of Texas, including the nearby 32 Ma Chinati Mountains caldera. The Red Hills intrusive system is contemporaneous with and genetically related to other Laramide magmatic systems (75-54 Ma) that host porphyry copper deposits in Arizona, southwestern New Mexico, and northern Mexico. These results significantly extend the Laramide magmatic province eastward and suggest that Laramide subduction-related magmatism and deformation are coextensive over a broad area of southwestern North America.

Bat ectoparasites from the Trans-Pecos region of Texas, including notes from Big Bend National Park.

Ectoparasites of 13 species of molossid, mormoopid, and vespertilionid bats from the Trans-Pecos region of Texas were studied, as follows: Antrozous pallidus (LeConte), Corynorhinus townsendii (Cooper), Eptesicus fuscus (Palisot de Beauvois), Lasiurus cinereus (Palisot de Beauvois), Mormoops megalophylla (Peters), Myotis thysanodes G. S. Miller, Myotis velifer (J. A. Allen), Myotis volans (H. Allen), Myotis yumanensis (H. Allen), Nyctinomops femorosaccus (Merriam), Nyctinomops macrotis (Gray), Pipistrellus hesperus (H. Allen), and Tadarida brasiliensis (I. Geof. St.-Hilaire). The bats were netted, examined for ectoparasites and released. Ectoparasites recovered included three species of flea, three species of streblid, three species of nycteribiid, two species of cimicid, two species of tick, and 17 species of mite. New ectoparasite records are given for hosts in seven instances and for the Trans-Pecos region of Texas in three instances.

Bed-Site Characteristics of Pronghorn Fawns

We examined microhabitat factors associated with bedding sites of pronghorn fawns in the Trans-Pecos Region of Texas. We marked 101 fawns during 3 consecutive fawning seasons, April-June 1990-92. We measured and compared 11 microhabitat characteristics of 127 and 489 bed sites from surviving (n = 11) and non-surviving (n = 89) fawns and compared these characteristics to 225 sites we selected randomly. Differences occurred between fawn-selected bed sites and random sites for shrub cover (P = 0.04), shrub density (P = 0.01), grass cover (P = 0.03), nearest concealing cover (NCC; P = 0.0001), rock cover (P = 0.008), and bed slope (P = 0.0001). Shrub cover, shrub density, and grass cover at bed sites of surviving fawns were more similar to that found at random sites than to bed sites of non-surviving fawns. Bed sites of survivors and non-survivors differed in rock cover (P = 0.03), slope (P = 0.008), and bed slope (P = 0.001) characteristics. Fawn age class appeared to influence preference for particular microhabitat characteristics; shrub density was greater (P = 0.027) and grass cover less (P = 0.0001) in young-age fawn bed sites. Environmental features that provided adequate concealment, but that also provided increased long-range visibility of the area surrounding the bed site, appeared to be favored for bedding. Overall, important microhabitat variables were shrub cover, shrub density, grass cover, NCC, and bed slope, and to a lesser extent rock cover, terrain slope, overstory height, and understory height. Management that encourages increased grass and forb production will provide necessary hiding cover for fawns.

Painting on Bones and Other Unusual Media in the Lower and Trans-Pecos Region of Texas and Coahuila

Poorly provenienced painted deer scapulae from three or four rock shelters in the mountainous region south and north of the Big Bend of the Rio Grande bear a strong resemblance to ethnographically documented musical instruments. Ethnohistoric and modern analogs suggest that these specimens combine four sacred qualities--bone, deer, paint, and music. Shamans who experience symbolic death during their trance states are reborn from their bones, the most durable element of the body. This belief is manifested in modern and ancient Native American art as well as in European and Asian folk myths. The reverence accorded to deer is evidenced in the folk stories, rock art, burial customs, and performances of the modern Native American population of northern Mexico. Paint, esp cially red ocher, is clearly associated with ritual in funerary contexts, in ceremonia rock art, and as body paint or tattoo. Finally, scapulae are still used in rituals as percussion instruments, either paired with rasps or strung togetheras rattles. These four sacred elements conjoin to grant ritual importance to archaeological objects that would otherwise be considered utilitarian or dietary refuse.

Parasites and selected diseases of collared peccaries (Tayassu tajacu) in the trans-pecos region of Texas.

Fifty-five collared peccaries (Tayassu tajacu) were collected from October 1988 through April 1991 from five counties within the Trans-Pecos region of Texas (USA) to monitor for diseases and parasites. No endoparasites were recovered on gross examination. Antibody to Borrelia burgdorferi was documented in one (2%) of 55 specimens. Three (6%) of 54 collared peccaries were positive for Yersinia pestis antibodies. All collared peccaries were negative for antibodies against Brucella spp., Francisella tularensis, Rickettsia rickettsii, and Rickettsia typhi. This is the first report of Borrelia sp. and Yersinia sp. pathogens in collared peccaries from this region of Texas.