David B Wester

Texas A&M University – Kingsville · Caesar Kleberg Wildlife Research Institute

Background: Complexity in landscape structure is often assessed using individual metrics related to ecological processes. However, this rarely incorporates important relationships among metrics and may miss landscape structure effects. Multivariate statistics provide techniques for assessing overall landscape structure effects. We assessed how mult...

Examination of Texas tortoise (Gopherus berlandieri) space use before and after prescribed fires in the summer and winter on a southern Texas cattle ranch.

Rangelands in the southwestern United States represent a current stronghold for northern bobwhite ( Colinus virginianus ); however, bobwhite populations in rangelands exhibit extreme inter‐annual variability in abundance in relation to fluctuating weather patterns. Recent declining bobwhite population trends within this region have led to the suppo...

Plant species richness is an important property of ecosystems that is altered by grazing. In a semiarid environment, we tested the hypotheses that (1) small‐scale herbaceous plant species richness declines linearly with increasing grazing intensity by large ungulates, (2) precipitation and percent sand interact with grazing intensity, and (3) respo...

Climate change is altering biodiversity of ecosystems worldwide by causing shifts in species’ home ranges, potential extinctions of species, and Extreme Climatic Events (ECEs), such as hurricanes and extreme temperatures. The purpose of this study was to examine effects of two extreme weather events on butterfly populations in the Gulf Prairies and...

Texas horned lizards (Phrynosoma cornutum; hereafter THL) were once abundant throughout Texas; however, their distribution and abundance have decreased, and currently they are listed as a threatened species in the state. Detection of THL can be difficult because of their cryptic nature and sporadic distribution. Using indirect signs such as fecal p...

Identification of buildings from remotely sensed imagery in urban and suburban areas is a challenging task. Light detection and Ranging (LiDAR) provides an opportunity to accurately identify buildings by identification of planar surfaces. Dense vegetation can limit the number of light particles that reach the ground, potentially creating false plan...

Gulf cordgrass (Spartina spartinae [Trin.] Merr. ex Hitchc.) and seacoast bluestem (Schizachyrium scoparium [Michx.] Nash var. littorale [Nash] Gould) are dominant native warm season grasses in the Texas Coastal Prairies and Marshes ecoregion. Mature Gulf cordgrass nutritive value is considered poor for grazing animals, while seacoast bluestem nutr...

Ecological light pollution is now recognized as a significant source of ecosystem alteration. We documented that holiday lights are a seasonal source of light pollution that constitute an ecological trap for eastern fox squirrels (Sciurus niger). Texas A&M University-Kingsville (TAMUK) wildlife students surveyed a 2-km walking transect 5 times per...

Southern Texas contains some of the last relatively unfragmented habitat for northern bobwhite (Colinus virginianus; hereafter, bobwhite) and scaled quail (Callipepla squamata) in the United States. Development of the Eagle Ford Shale hydrocarbon formation in this region could negatively impact quail and their habitat. Our objective was to examine...

Usable space for northern bobwhite (Colinus virginianus) has been reduced across South Texas rangelands because of the spread of non-native, invasive grasses. A native grass, tanglehead (Heteropogon contortus), has also rapidly expanded its dominance in South Texas within the past 25 yr. It has formed high-density monocultures, similar to non-nativ...

Wildlife-vehicle collisions can have a substantial influence on the mortality rates of many wildlife populations. Crossing structures are designed to mitigate the impact of road mortality by allowing safe passage of wildlife above or below roads, and connect to suitable areas on both sides of the road. Ocelots (Leopardus pardalis) are a federally e...

Formative patterns of vegetation responses to cattle grazing can be difficult to detect because of innate heterogeneity of vegetation communities and grazing patterns, especially in semiarid environments. Nonetheless, some of this heterogeneity can be accounted for using appropriate experimental designs and statistical analyses. Bork and Werner (19...

Rainfall is a strong driver of quail populations on southwestern rangelands and can account for a large portion (~70–95%) of the variability in regional quail production and abundance. Landowners have attempted to moderate these boom‐and‐bust fluctuations via management; however, presently it is unknown whether management can increase or stabilize...

Interspecific interactions among mesocarnivores can influence community dynamics and resource partitioning. Insights into these interactions can enhance understanding of local ecological processes that have impacts on pathogen transmission, such as the rabies lyssavirus. Host species ecology can provide an important baseline for disease management...

Reducing grass standing crop by grazing may increase forbs and benefit wildlife that depend on forbs. However, precipitation and soil texture also strongly influence forb standing crop. We determined if standing crop of forbs selected by white-tailed deer (Odocoileus virginianus Zimm.) is more strongly influenced by grazing or precipitation. Ungula...

Invasive grasses are in most cases introduced species able to outcompete native species. Buffelgrass (Cenchrus ciliaris), Guineagrass (Urochloa minima), and Old World bluestems (Dichanthium spp.) are typical examples of invasive species in southeastern United States. However, native grasses such as tanglehead (Heteropogon contortus) can become inva...

Montezuma quail (Cyrtonyx montezumae) inhabit oak (Quercus spp.)‐juniper (Juniperus spp.) woodlands throughout Mexico and the southwestern United States. In Texas, USA, Montezuma quail occur in the Edwards Plateau and Trans‐Pecos Mountains and Basins (Trans‐Pecos), 2 ecoregions with contrasting juniper patterns. Ashe juniper (Juniperus ashei) domin...

Caregivers of captive wildlife are at risk of zoonotic diseases because they have prolonged contact with and potential exposure to many species of wildlife, their bodily fluids, and feces. One such zoonosis is Baylisascaris procyonis, an intestinal parasite of raccoons (Procyon lotor). Larvae of B. procyonis can cause blindness, paralysis, and deat...

Populations of northern bobwhites ( Colinus virginianus ; hereafter bobwhite) have been declining across their geographic range in North America, prompting consideration of the role parasites may play. We conducted this study to learn about the helminth fauna in South Texas, a region that supports a sustainable bobwhite population. Helminths were e...

Context Road networks can negatively impact wildlife populations through habitat fragmentation, decreased landscape connectivity, and wildlife-vehicle collisions, thereby influencing the spatial ecology and population dynamics of imperiled species. The ocelot (Leopardus pardalis) is a federally endangered wild felid in South Texas, with a high mort...

The northern bobwhite (Colinus virginianus; bobwhite) exists at the edge of its thermal tolerance in southern Texas, USA, a region characterized by extreme heat and periodic drought. Extreme heat and drought events are predicted to increase in frequency and intensity in semi‐arid regions, leading biologists to emphasize management of thermal cover....

Baylisascaris procyonis is a zoonotic parasite that can cause serious health issues in their intermediate hosts. Eggs of the parasite are shed in the feces of raccoons ( Procyon lotor), the definitive host, and can remain viable in the environment for years. Temperatures at 49 C are the LD50 for B. procyonis eggs. Our objective was to determine the...

The application of unmanned aerial vehicles (UAVs) in the monitoring and management of rangelands has exponentially increased in recent years due to the miniaturization of sensors, ability to capture imagery with high spatial resolution, lower altitude platforms, and the ease of flying UAVs in remote environments. The aim of this research was to de...

White-tailed deer ( Odocoileus virginianus) serve as a host for cattle fever ticks ( Rhipicephalus [ Boophilus] microplus and R. [ B.] annulatus; CFTs); therefore, deer are a concern for CFT control programs in southern Texas. Systemic (oral delivery of ivermectin) and topical (permethrin on pelage) treatment devices have been developed for white-t...

The Midcontinent population of sandhill cranes (Antigone canadensis) has historically been classified into 3 putative subspecies, but genetic analyses have identified only 2 genetically distinct subspecies. Previous studies have successfully used morphometrics in combination with an individual's sex to differentiate subspecies of sandhill cranes th...

The Jamaican Boa Chilabothrus subflavus (Boidae) is a Jamaican-protected species whose numbers and distribution have declined during the last century. In order to protect Jamaican Boas, translocation has been recommended as a conservation strategy. From December 2010 to November 2012 a short-distance translocation (SDT) of seven resident female Jam...

Kuenzler's hedgehog cactus (Echinocereus fendleri var. kuenzleri [Castetter, P. Pierce & K.H. Schwer.] L.D. Benson) is a federally listed threatened species found in pinyon-juniper habitats in south-central New Mexico, USA. Little is known about effects of prescribed fire on this species. First- and second-year responses of plants burned in the fie...

Identifying impacts of invasive grasses on seed banks is critical in developing restoration strategies. Tanglehead (Heteropogon contortus) and Lehmann lovegrass (Eragrostis Lehmanniana) have increased throughout the Texas Coastal Sand Plain. We examined effects of tanglehead or lovegrass abundance (as reflected in cover) on seed banks in sites domi...

Helminths were examined from 145 scaled quail ( Callipepla squamata ) collected during the 2012–2013, 2013–2014 and 2014–2015 hunting seasons from a semi-arid region of Texas that spans four ecoregions. Helminth infracommunities were species poor, averaging 1.7 (range 1–4) species. Six species occurred within the component community of which one (...

Non‐native grasses are frequently sown in the southwestern United States for livestock forage and erosion control. These grasses often spread from areas where they are planted and replace native grasses and forbs. We tested the hypothesis that chestnut‐bellied scaled quail (Callipepla squamata castanogastris) avoid locations dominated by non‐native...

Density‐dependent behavior underpins white‐tailed deer ( Odocoileus virginianus ) theory and management application in North America, but strength or frequency of the phenomenon has varied across the geographic range of the species. The modifying effect of stochastic environments and poor‐quality habitats on density‐dependent behavior has been reco...

Animals use physiological and behavioral adaptations to maintain constant body temperatures when environmental temperatures are outside of their thermoneutral zone. We define the temperature suitability bounds as the range of temperatures above and below which animals avoid locations because of unfavorable thermal conditions. Temperatures outside t...

Invasive plants are a serious concern throughout many rangelands in North America because of their detrimental effects on vegetation community composition, diversity and wildlife habitat. Growing evidence shows that invasive plants affect ecosystem processes such as energy and nutrient cycling and soil microbial associations. Tanglehead (Heteropogo...

The wildlife ranching industry relies on providing supplemental grain to game animals to enhance wildlife viewing and hunting opportunities. Unfortunately, environmental climate and storage conditions can create the production of aflatoxins, a toxic fungal metabolite. Our objective was to determine temporal differences in aflatoxin concentrations o...

The American Alligator (Alligator mississippiensis) is a crocodilian species that was once listed as endangered in the United States, but is now harvested both recreationally and commercially throughout its range in the southeastern United States. Harvest of alligators typically includes egg collecting and hunting. However, review of scientific lit...

Restoration is difficult when topsoil and subsoil become mixed during pipeline construction. We studied soil properties, seedling emergence and establishment after pipeline construction in the Rio Grande Plains, Texas following physical (with or without erosion control blanket, ECB), chemical (humic substances, HS), and/or biological (native specie...

Topsoils often are removed from energy production sites and stock-piled for use later in restoration activities. Effects of this practice on soil seed banks are unknown. We examined seed bank size, species richness, and species composition of stock-piled topsoils as affected by sampling depth and sampling date at two study sites in the western Rio...

Understanding thermal ecology of endotherms is becoming increasingly important with predicted increases in temperature associated with climate change. Patterns of resource selection may depend in part on temperature thresholds outside which animals avoid warmer or cooler temperatures. During summer, northern bobwhites (Colinus virginianus; hereafte...

Previous studies have explored spatial ecology and habitat use of alligators and other crocodilian species. However, few studies have explored these characteristics in urban environments. We studied an alligator population that occurred in an urban-influenced ecosystem, a habitat that has received little scientific attention. Our objectives were to...

One hundred and sixty-one northern bobwhites ( Colinus virginianus ; hereafter ‘bobwhite’) were examined from the Rolling Plains ecoregion of Texas and western Oklahoma from 2011 to 2013. Complete necropsies yielded 13 species, of which two are new host ( Gongylonema phasianella ) and region ( Eucoleus contortus ) records and three ( Dispharynx nas...

Gulf cordgrass is a perennial bunchgrass native to North and South America. In the United States and Mexico, it is found in coastal prairies and marshes along the coast of the Gulf of Mexico, and occasionally further inland in low–lying areas. In South America, it is found along the Caribbean coast and inland in Argentina and Paraguay. Gulf cordgra...

Usable space for northern bobwhites (Colinus virginianus) has declined significantly over the past 3 decades in Texas because non-native grasses have replaced native vegetation. We hypothesized that burning patches in pastures dominated by buffelgrass (Pennisetum ciliare) and Old World bluestems (Bothriochloa spp. and Dichanthium spp.) followed by...

On the Ground • Tanglehead is a native bunchgrass with a pan-tropical distribution. Historically, tanglehead was common but not abundant in southern Texas and was considered a decreaser whose presence indicated good range condition. • Beginning in the late 1990s, the Texas Coastal Sand Plain ecoregion witnessed dramatic increases in the abundance...

Northern bobwhites (Colinus virginianus) are sensitive to extreme thermal conditions, particularly along the southern and western peripheries of their range. In south Texas, bobwhites are exposed to temperatures that frequently exceed 39°C. As mean and maximum temperatures during summer are expected to increase, thermal fragmentation of suitable mi...

Sorghum [Sorghum bicolor (L.) Moench.] and sorghum-sudangrass (S. bicolor × S. bicolor drummondii) silage utilization in cattle diets has increased in recent years. The objectives of this study were to compare the forage mass and nutritive value of photoperiod-sensitive (PS) sorghum and hybrid sister lines with or without the BMR trait, and determi...

Abstract Introduction Deforestation significantly impacts large carnivores that depend on large tracts of interconnected forest habitat and that are sensitive to human activities. Understanding the relationship between habitat use and spatial distribution of such species across human modified landscapes is critical when planning effective conservat...

Slender rush-pea (Hoffmannseggia tenella) is an endangered herbaceous legume endemic to southern Texas. Agricultural expansion and invasive nonnative grasses have caused reductions in its range, threatening existing populations. We compared three management techniques that control competition to no management (control) to determine effects on slend...

Agricultural drainage ditches function as first-order streams and affect nutrient management. Soil mesocosms from a ditch featuring a vertical (increasing upward) gradient in iron (Fe) and phosphorus (P) were subjected to hydraulic and soil treatments. These manipulations mimicked aspects of dredging and controlled drainage and inspected the soil r...

Cattle fever ticks (CFT), vectors of bovine babesiosis and anaplasmosis, were eradicated from the United States by 1943, but are frequently reintroduced from neighboring border states of Mexico via stray cattle and wildlife hosts including white-tailed deer (Odocoileus virginianus) (WTD) and nilgai antelope (Boselaphus tragocamelus). Nilgai antelop...

Exposure to smoke can influence the germination of seeds in many fire-prone ecosystems, but this effect is not well studied in grasslands. Smoke treatments such as smoke water could be useful as management and restoration tools if the response of target species in natural settings is well understood. We tested eight species native to the southern H...

Northern bobwhite (Colinus virginianus) populations have been declining in Texas during the last 2 decades. This decline also is occurring in areas with apparently ample habitat such as the Rolling Plains of Texas, USA. The goal of our study was to examine the efficacy of translocating wild-trapped bobwhites into recently depopulated areas in the e...

Baylisascaris procyonis is a large ascarid of raccoons (Procyon lotor) and is a zoonotic threat. We documented the potential rate a raccoon population can contaminate their environment with B. procyonis eggs. We estimated the population size of raccoons using a 9 × 7 trapping grid of Havahart traps, identified locations of raccoon scats through sys...

Baylisascaris procyonis is a nematode whose definitive host is the raccoon (Procyon lotor). Adult parasites are not particularly pathogenic to raccoons; however, larvae in intermediate hosts can cause visceral, ocular, and neural larva migrans. Humans serve as dead-end hosts and pathological responses are similar as those found in infected intermed...